MAINTAINERS | 3 +- arch/s390/include/asm/nospec-insn.h | 2 +- arch/s390/kernel/vmlinux.lds.S | 2 +- arch/x86/Kconfig | 1 + arch/x86/include/asm/alternative.h | 4 + arch/x86/include/asm/asm.h | 5 + arch/x86/include/asm/bug.h | 1 + arch/x86/include/asm/cpufeature.h | 1 + arch/x86/include/asm/jump_label.h | 1 + arch/x86/kernel/alternative.c | 51 +- arch/x86/kernel/kprobes/opt.c | 4 - arch/x86/kernel/module.c | 15 +- include/asm-generic/vmlinux.lds.h | 40 +- include/linux/annotate.h | 134 ++ include/linux/compiler.h | 8 +- include/linux/elfnote.h | 13 +- include/linux/init.h | 3 +- include/linux/interval_tree.h | 4 + include/linux/interval_tree_generic.h | 2 +- include/linux/livepatch.h | 25 +- include/linux/livepatch_external.h | 76 + include/linux/livepatch_helpers.h | 77 + include/linux/mm.h | 2 + include/linux/objtool.h | 96 +- include/linux/objtool_types.h | 2 + kernel/livepatch/Kconfig | 12 + kernel/livepatch/core.c | 8 +- scripts/Makefile.lib | 7 +- scripts/Makefile.vmlinux_o | 2 +- scripts/link-vmlinux.sh | 3 +- scripts/livepatch/fix-patch-lines | 79 + scripts/livepatch/init.c | 108 ++ scripts/livepatch/klp-build | 827 ++++++++ scripts/mod/modpost.c | 5 + scripts/module.lds.S | 22 +- tools/include/linux/interval_tree_generic.h | 10 +- tools/include/linux/livepatch_external.h | 76 + tools/include/linux/objtool_types.h | 2 + tools/include/linux/string.h | 14 + tools/objtool/Build | 4 +- tools/objtool/Makefile | 48 +- tools/objtool/arch/loongarch/decode.c | 6 +- tools/objtool/arch/loongarch/orc.c | 1 - tools/objtool/arch/powerpc/decode.c | 7 +- tools/objtool/arch/x86/decode.c | 63 +- tools/objtool/arch/x86/orc.c | 1 - tools/objtool/arch/x86/special.c | 2 +- tools/objtool/builtin-check.c | 96 +- tools/objtool/builtin-klp.c | 53 + tools/objtool/check.c | 875 +++++---- tools/objtool/elf.c | 781 ++++++-- tools/objtool/include/objtool/arch.h | 5 +- tools/objtool/include/objtool/builtin.h | 11 +- tools/objtool/include/objtool/check.h | 6 +- tools/objtool/include/objtool/checksum.h | 43 + .../objtool/include/objtool/checksum_types.h | 25 + tools/objtool/include/objtool/elf.h | 196 +- tools/objtool/include/objtool/endianness.h | 9 +- tools/objtool/include/objtool/klp.h | 35 + tools/objtool/include/objtool/objtool.h | 4 +- tools/objtool/include/objtool/util.h | 19 + tools/objtool/include/objtool/warn.h | 40 + tools/objtool/klp-diff.c | 1723 +++++++++++++++++ tools/objtool/klp-post-link.c | 168 ++ tools/objtool/objtool.c | 42 +- tools/objtool/orc_dump.c | 1 - tools/objtool/orc_gen.c | 9 +- tools/objtool/special.c | 14 +- tools/objtool/sync-check.sh | 2 + tools/objtool/weak.c | 7 + 70 files changed, 5152 insertions(+), 891 deletions(-) create mode 100644 include/linux/annotate.h create mode 100644 include/linux/livepatch_external.h create mode 100644 include/linux/livepatch_helpers.h create mode 100755 scripts/livepatch/fix-patch-lines create mode 100644 scripts/livepatch/init.c create mode 100755 scripts/livepatch/klp-build create mode 100644 tools/include/linux/livepatch_external.h create mode 100644 tools/objtool/builtin-klp.c create mode 100644 tools/objtool/include/objtool/checksum.h create mode 100644 tools/objtool/include/objtool/checksum_types.h create mode 100644 tools/objtool/include/objtool/klp.h create mode 100644 tools/objtool/include/objtool/util.h create mode 100644 tools/objtool/klp-diff.c create mode 100644 tools/objtool/klp-post-link.c
Changes since v3 (https://lore.kernel.org/cover.1750980516.git.jpoimboe@kernel.org):
- Get rid of the SHF_MERGE+SHF_WRITE toolchain shenanigans in favor of
simple .discard.annotate_data annotations
- Fix potential double free in elf_create_reloc()
- Sync interval_tree_generic.h (Peter)
- Refactor prefix symbol creation error handling
- Rebase on tip/master and fix new issue (--checksum getting added with --noabs)
(v3..v4 diff below)
----
This series introduces new objtool features and a klp-build script to
generate livepatch modules using a source .patch as input.
This builds on concepts from the longstanding out-of-tree kpatch [1]
project which began in 2012 and has been used for many years to generate
livepatch modules for production kernels. However, this is a complete
rewrite which incorporates hard-earned lessons from 12+ years of
maintaining kpatch.
Key improvements compared to kpatch-build:
- Integrated with objtool: Leverages objtool's existing control-flow
graph analysis to help detect changed functions.
- Works on vmlinux.o: Supports late-linked objects, making it
compatible with LTO, IBT, and similar.
- Simplified code base: ~3k fewer lines of code.
- Upstream: No more out-of-tree #ifdef hacks, far less cruft.
- Cleaner internals: Vastly simplified logic for symbol/section/reloc
inclusion and special section extraction.
- Robust __LINE__ macro handling: Avoids false positive binary diffs
caused by the __LINE__ macro by introducing a fix-patch-lines script
which injects #line directives into the source .patch to preserve
the original line numbers at compile time.
The primary user interface is the klp-build script which does the
following:
- Builds an original kernel with -function-sections and
-fdata-sections, plus objtool function checksumming.
- Applies the .patch file and rebuilds the kernel using the same
options.
- Runs 'objtool klp diff' to detect changed functions and generate
intermediate binary diff objects.
- Builds a kernel module which links the diff objects with some
livepatch module init code (scripts/livepatch/init.c).
- Finalizes the livepatch module (aka work around linker wreckage)
using 'objtool klp post-link'.
I've tested with a variety of patches on defconfig and Fedora-config
kernels with both GCC and Clang.
These patches can also be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git klp-build-v3
Please test!
[1] https://github.com/dynup/kpatch
Josh Poimboeuf (63):
s390/vmlinux.lds.S: Prevent thunk functions from getting placed with
normal text
vmlinux.lds: Unify TEXT_MAIN, DATA_MAIN, and related macros
x86/module: Improve relocation error messages
x86/kprobes: Remove STACK_FRAME_NON_STANDARD annotation
compiler: Tweak __UNIQUE_ID() naming
compiler.h: Make addressable symbols less of an eyesore
elfnote: Change ELFNOTE() to use __UNIQUE_ID()
kbuild: Remove 'kmod_' prefix from __KBUILD_MODNAME
modpost: Ignore unresolved section bounds symbols
x86/alternative: Refactor INT3 call emulation selftest
interval_tree: Sync interval_tree_generic.h with tools
interval_tree: Fix ITSTATIC usage for *_subtree_search()
objtool: Make find_symbol_containing() less arbitrary
objtool: Fix broken error handling in read_symbols()
objtool: Propagate elf_truncate_section() error in elf_write()
objtool: Remove error handling boilerplate
objtool: Add empty symbols to the symbol tree again
objtool: Fix interval tree insertion for zero-length symbols
objtool: Fix weak symbol detection
objtool: Fix x86 addend calculation
objtool: Fix __pa_symbol() relocation handling
objtool: Fix "unexpected end of section" warning for alternatives
objtool: Check for missing annotation entries in read_annotate()
objtool: Const string cleanup
objtool: Clean up compiler flag usage
objtool: Remove .parainstructions reference
objtool: Convert elf iterator macros to use 'struct elf'
objtool: Add section/symbol type helpers
objtool: Mark .cold subfunctions
objtool: Fix weak symbol hole detection for .cold functions
objtool: Mark prefix functions
objtool: Simplify reloc offset calculation in unwind_read_hints()
objtool: Avoid emptying lists for duplicate sections
objtool: Rename --Werror to --werror
objtool: Resurrect --backup option
objtool: Reindent check_options[]
objtool: Refactor add_jump_destinations()
objtool: Simplify special symbol handling in elf_update_symbol()
objtool: Generalize elf_create_symbol()
objtool: Generalize elf_create_section()
objtool: Add elf_create_data()
objtool: Add elf_create_reloc() and elf_init_reloc()
objtool: Add elf_create_file()
objtool: Add annotype() helper
objtool: Move ANNOTATE* macros to annotate.h
objtool: Add ANNOTATE_DATA_SPECIAL
x86/asm: Annotate special section entries
objtool: Unify STACK_FRAME_NON_STANDARD entry sizes
objtool/klp: Add --checksum option to generate per-function checksums
objtool/klp: Add --debug-checksum=<funcs> to show per-instruction
checksums
objtool/klp: Introduce klp diff subcommand for diffing object files
objtool/klp: Add --debug option to show cloning decisions
objtool/klp: Add post-link subcommand to finalize livepatch modules
objtool: Refactor prefix symbol creation code
objtool: Add base objtool support for livepatch modules
livepatch: Add CONFIG_KLP_BUILD
kbuild,objtool: Defer objtool validation step for CONFIG_KLP_BUILD
livepatch/klp-build: Introduce fix-patch-lines script to avoid
__LINE__ diff noise
livepatch/klp-build: Add stub init code for livepatch modules
livepatch/klp-build: Introduce klp-build script for generating
livepatch modules
livepatch/klp-build: Add --debug option to show cloning decisions
livepatch/klp-build: Add --show-first-changed option to show function
divergence
livepatch: Introduce source code helpers for livepatch modules
MAINTAINERS | 3 +-
arch/s390/include/asm/nospec-insn.h | 2 +-
arch/s390/kernel/vmlinux.lds.S | 2 +-
arch/x86/Kconfig | 1 +
arch/x86/include/asm/alternative.h | 4 +
arch/x86/include/asm/asm.h | 5 +
arch/x86/include/asm/bug.h | 1 +
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/include/asm/jump_label.h | 1 +
arch/x86/kernel/alternative.c | 51 +-
arch/x86/kernel/kprobes/opt.c | 4 -
arch/x86/kernel/module.c | 15 +-
include/asm-generic/vmlinux.lds.h | 40 +-
include/linux/annotate.h | 134 ++
include/linux/compiler.h | 8 +-
include/linux/elfnote.h | 13 +-
include/linux/init.h | 3 +-
include/linux/interval_tree.h | 4 +
include/linux/interval_tree_generic.h | 2 +-
include/linux/livepatch.h | 25 +-
include/linux/livepatch_external.h | 76 +
include/linux/livepatch_helpers.h | 77 +
include/linux/mm.h | 2 +
include/linux/objtool.h | 96 +-
include/linux/objtool_types.h | 2 +
kernel/livepatch/Kconfig | 12 +
kernel/livepatch/core.c | 8 +-
scripts/Makefile.lib | 7 +-
scripts/Makefile.vmlinux_o | 2 +-
scripts/link-vmlinux.sh | 3 +-
scripts/livepatch/fix-patch-lines | 79 +
scripts/livepatch/init.c | 108 ++
scripts/livepatch/klp-build | 827 ++++++++
scripts/mod/modpost.c | 5 +
scripts/module.lds.S | 22 +-
tools/include/linux/interval_tree_generic.h | 10 +-
tools/include/linux/livepatch_external.h | 76 +
tools/include/linux/objtool_types.h | 2 +
tools/include/linux/string.h | 14 +
tools/objtool/Build | 4 +-
tools/objtool/Makefile | 48 +-
tools/objtool/arch/loongarch/decode.c | 6 +-
tools/objtool/arch/loongarch/orc.c | 1 -
tools/objtool/arch/powerpc/decode.c | 7 +-
tools/objtool/arch/x86/decode.c | 63 +-
tools/objtool/arch/x86/orc.c | 1 -
tools/objtool/arch/x86/special.c | 2 +-
tools/objtool/builtin-check.c | 96 +-
tools/objtool/builtin-klp.c | 53 +
tools/objtool/check.c | 875 +++++----
tools/objtool/elf.c | 781 ++++++--
tools/objtool/include/objtool/arch.h | 5 +-
tools/objtool/include/objtool/builtin.h | 11 +-
tools/objtool/include/objtool/check.h | 6 +-
tools/objtool/include/objtool/checksum.h | 43 +
.../objtool/include/objtool/checksum_types.h | 25 +
tools/objtool/include/objtool/elf.h | 196 +-
tools/objtool/include/objtool/endianness.h | 9 +-
tools/objtool/include/objtool/klp.h | 35 +
tools/objtool/include/objtool/objtool.h | 4 +-
tools/objtool/include/objtool/util.h | 19 +
tools/objtool/include/objtool/warn.h | 40 +
tools/objtool/klp-diff.c | 1723 +++++++++++++++++
tools/objtool/klp-post-link.c | 168 ++
tools/objtool/objtool.c | 42 +-
tools/objtool/orc_dump.c | 1 -
tools/objtool/orc_gen.c | 9 +-
tools/objtool/special.c | 14 +-
tools/objtool/sync-check.sh | 2 +
tools/objtool/weak.c | 7 +
70 files changed, 5152 insertions(+), 891 deletions(-)
create mode 100644 include/linux/annotate.h
create mode 100644 include/linux/livepatch_external.h
create mode 100644 include/linux/livepatch_helpers.h
create mode 100755 scripts/livepatch/fix-patch-lines
create mode 100644 scripts/livepatch/init.c
create mode 100755 scripts/livepatch/klp-build
create mode 100644 tools/include/linux/livepatch_external.h
create mode 100644 tools/objtool/builtin-klp.c
create mode 100644 tools/objtool/include/objtool/checksum.h
create mode 100644 tools/objtool/include/objtool/checksum_types.h
create mode 100644 tools/objtool/include/objtool/klp.h
create mode 100644 tools/objtool/include/objtool/util.h
create mode 100644 tools/objtool/klp-diff.c
create mode 100644 tools/objtool/klp-post-link.c
--
2.50.0
diff --git a/arch/Kconfig b/arch/Kconfig
index 4fb74eade61af..b13e86ad23e2f 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1368,9 +1368,6 @@ config HAVE_NOINSTR_HACK
config HAVE_NOINSTR_VALIDATION
bool
-config NEED_MODULE_PERMISSIONS_FIX
- bool
-
config HAVE_UACCESS_VALIDATION
bool
select OBJTOOL
diff --git a/arch/um/include/asm/Kbuild b/arch/um/include/asm/Kbuild
index 1b9b82bbe3220..b6810db24ca4d 100644
--- a/arch/um/include/asm/Kbuild
+++ b/arch/um/include/asm/Kbuild
@@ -5,6 +5,7 @@ generic-y += device.h
generic-y += dma-mapping.h
generic-y += emergency-restart.h
generic-y += exec.h
+generic-y += extable.h
generic-y += ftrace.h
generic-y += hw_irq.h
generic-y += irq_regs.h
diff --git a/arch/um/include/shared/common-offsets.h b/arch/um/include/shared/common-offsets.h
index a6f77cb6aa7e1..8ca66a1918c3a 100644
--- a/arch/um/include/shared/common-offsets.h
+++ b/arch/um/include/shared/common-offsets.h
@@ -18,6 +18,3 @@ DEFINE(UM_NSEC_PER_USEC, NSEC_PER_USEC);
DEFINE(UM_KERN_GDT_ENTRY_TLS_ENTRIES, GDT_ENTRY_TLS_ENTRIES);
DEFINE(UM_SECCOMP_ARCH_NATIVE, SECCOMP_ARCH_NATIVE);
-
-DEFINE(ALT_INSTR_SIZE, sizeof(struct alt_instr));
-DEFINE(EXTABLE_SIZE, sizeof(struct exception_table_entry));
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 073274e35da5e..986d31587e999 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -305,7 +305,6 @@ config X86
select HOTPLUG_SPLIT_STARTUP if SMP && X86_32
select IRQ_FORCED_THREADING
select LOCK_MM_AND_FIND_VMA
- select NEED_MODULE_PERMISSIONS_FIX
select NEED_PER_CPU_EMBED_FIRST_CHUNK
select NEED_PER_CPU_PAGE_FIRST_CHUNK
select NEED_SG_DMA_LENGTH
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index eb24d9ba30d7f..b14c045679e16 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -197,8 +197,8 @@ static inline int alternatives_text_reserved(void *start, void *end)
"773:\n"
#define ALTINSTR_ENTRY(ft_flags) \
- ".pushsection .altinstructions, \"aM\", @progbits, " \
- __stringify(ALT_INSTR_SIZE) "\n" \
+ ".pushsection .altinstructions,\"a\"\n" \
+ ANNOTATE_DATA_SPECIAL \
" .long 771b - .\n" /* label */ \
" .long 774f - .\n" /* new instruction */ \
" .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
@@ -208,6 +208,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
".pushsection .altinstr_replacement, \"ax\"\n" \
+ ANNOTATE_DATA_SPECIAL \
"# ALT: replacement\n" \
"774:\n\t" newinstr "\n775:\n" \
".popsection\n"
@@ -338,6 +339,7 @@ void nop_func(void);
* instruction. See apply_alternatives().
*/
.macro altinstr_entry orig alt ft_flags orig_len alt_len
+ ANNOTATE_DATA_SPECIAL
.long \orig - .
.long \alt - .
.4byte \ft_flags
@@ -361,11 +363,12 @@ void nop_func(void);
741: \
.skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;\
742: \
- .pushsection .altinstructions, "aM", @progbits, ALT_INSTR_SIZE ;\
+ .pushsection .altinstructions,"a" ; \
altinstr_entry 740b,743f,flag,742b-740b,744f-743f ; \
.popsection ; \
.pushsection .altinstr_replacement,"ax" ; \
743: \
+ ANNOTATE_DATA_SPECIAL ; \
newinst ; \
744: \
.popsection ;
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index ecb28d2bc6730..bd62bd87a841e 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -2,6 +2,8 @@
#ifndef _ASM_X86_ASM_H
#define _ASM_X86_ASM_H
+#include <linux/annotate.h>
+
#ifdef __ASSEMBLER__
# define __ASM_FORM(x, ...) x,## __VA_ARGS__
# define __ASM_FORM_RAW(x, ...) x,## __VA_ARGS__
@@ -124,21 +126,18 @@ static __always_inline __pure void *rip_rel_ptr(void *p)
#ifdef __KERNEL__
-#ifndef COMPILE_OFFSETS
-#include <asm/asm-offsets.h>
-#endif
-
# include <asm/extable_fixup_types.h>
/* Exception table entry */
#ifdef __ASSEMBLER__
-# define _ASM_EXTABLE_TYPE(from, to, type) \
- .pushsection "__ex_table", "aM", @progbits, EXTABLE_SIZE; \
- .balign 4 ; \
- .long (from) - . ; \
- .long (to) - . ; \
- .long type ; \
+# define _ASM_EXTABLE_TYPE(from, to, type) \
+ .pushsection "__ex_table","a" ; \
+ .balign 4 ; \
+ ANNOTATE_DATA_SPECIAL ; \
+ .long (from) - . ; \
+ .long (to) - . ; \
+ .long type ; \
.popsection
# ifdef CONFIG_KPROBES
@@ -181,18 +180,18 @@ static __always_inline __pure void *rip_rel_ptr(void *p)
".purgem extable_type_reg\n"
# define _ASM_EXTABLE_TYPE(from, to, type) \
- " .pushsection __ex_table, \"aM\", @progbits, " \
- __stringify(EXTABLE_SIZE) "\n" \
+ " .pushsection \"__ex_table\",\"a\"\n" \
" .balign 4\n" \
+ ANNOTATE_DATA_SPECIAL \
" .long (" #from ") - .\n" \
" .long (" #to ") - .\n" \
" .long " __stringify(type) " \n" \
" .popsection\n"
# define _ASM_EXTABLE_TYPE_REG(from, to, type, reg) \
- " .pushsection __ex_table, \"aM\", @progbits, " \
- __stringify(EXTABLE_SIZE) "\n" \
+ " .pushsection \"__ex_table\",\"a\"\n" \
" .balign 4\n" \
+ ANNOTATE_DATA_SPECIAL \
" .long (" #from ") - .\n" \
" .long (" #to ") - .\n" \
DEFINE_EXTABLE_TYPE_REG \
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index db1522fdbd108..3910db28e2f5b 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -56,7 +56,8 @@
#define _BUG_FLAGS_ASM(ins, file, line, flags, size, extra) \
"1:\t" ins "\n" \
- ".pushsection __bug_table, \"aM\", @progbits, " size "\n" \
+ ".pushsection __bug_table,\"aw\"\n" \
+ ANNOTATE_DATA_SPECIAL \
__BUG_ENTRY(file, line, flags) \
"\t.org 2b + " size "\n" \
".popsection\n" \
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 893cbca37fe99..fc5f32d4da6e1 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -101,6 +101,7 @@ static __always_inline bool _static_cpu_has(u16 bit)
asm goto(ALTERNATIVE_TERNARY("jmp 6f", %c[feature], "", "jmp %l[t_no]")
".pushsection .altinstr_aux,\"ax\"\n"
"6:\n"
+ ANNOTATE_DATA_SPECIAL
" testb %[bitnum], %a[cap_byte]\n"
" jnz %l[t_yes]\n"
" jmp %l[t_no]\n"
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 7a6b0e5d85c19..e0a6930a4029a 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -12,17 +12,13 @@
#include <linux/stringify.h>
#include <linux/types.h>
-#ifndef COMPILE_OFFSETS
-#include <generated/bounds.h>
-#endif
-
-#define JUMP_TABLE_ENTRY(key, label) \
- ".pushsection __jump_table, \"aM\", @progbits, " \
- __stringify(JUMP_ENTRY_SIZE) "\n\t" \
- _ASM_ALIGN "\n\t" \
- ".long 1b - . \n\t" \
- ".long " label " - . \n\t" \
- _ASM_PTR " " key " - . \n\t" \
+#define JUMP_TABLE_ENTRY(key, label) \
+ ".pushsection __jump_table, \"aw\" \n\t" \
+ _ASM_ALIGN "\n\t" \
+ ANNOTATE_DATA_SPECIAL \
+ ".long 1b - . \n\t" \
+ ".long " label " - . \n\t" \
+ _ASM_PTR " " key " - . \n\t" \
".popsection \n\t"
/* This macro is also expanded on the Rust side. */
diff --git a/arch/x86/include/asm/static_call.h b/arch/x86/include/asm/static_call.h
index e03ad9bbbf59d..41502bd2afd64 100644
--- a/arch/x86/include/asm/static_call.h
+++ b/arch/x86/include/asm/static_call.h
@@ -58,8 +58,7 @@
ARCH_DEFINE_STATIC_CALL_TRAMP(name, __static_call_return0)
#define ARCH_ADD_TRAMP_KEY(name) \
- asm(".pushsection .static_call_tramp_key, \"aM\", @progbits, " \
- __stringify(STATIC_CALL_TRAMP_KEY_SIZE) "\n" \
+ asm(".pushsection .static_call_tramp_key, \"a\" \n" \
".long " STATIC_CALL_TRAMP_STR(name) " - . \n" \
".long " STATIC_CALL_KEY_STR(name) " - . \n" \
".popsection \n")
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index 0586d237b8866..32ba599a51f88 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -124,7 +124,4 @@ static void __used common(void)
OFFSET(ARIA_CTX_rounds, aria_ctx, rounds);
#endif
- BLANK();
- DEFINE(ALT_INSTR_SIZE, sizeof(struct alt_instr));
- DEFINE(EXTABLE_SIZE, sizeof(struct exception_table_entry));
}
diff --git a/arch/x86/um/shared/sysdep/kernel-offsets.h b/arch/x86/um/shared/sysdep/kernel-offsets.h
index 8215a0200ddd9..6fd1ed4003992 100644
--- a/arch/x86/um/shared/sysdep/kernel-offsets.h
+++ b/arch/x86/um/shared/sysdep/kernel-offsets.h
@@ -1,5 +1,4 @@
/* SPDX-License-Identifier: GPL-2.0 */
-#define COMPILE_OFFSETS
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/elf.h>
@@ -8,7 +7,6 @@
#include <linux/audit.h>
#include <asm/mman.h>
#include <asm/seccomp.h>
-#include <asm/extable.h>
/* workaround for a warning with -Wmissing-prototypes */
void foo(void);
diff --git a/include/linux/annotate.h b/include/linux/annotate.h
new file mode 100644
index 0000000000000..7c10d34d198cf
--- /dev/null
+++ b/include/linux/annotate.h
@@ -0,0 +1,134 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_ANNOTATE_H
+#define _LINUX_ANNOTATE_H
+
+#include <linux/objtool_types.h>
+
+#ifdef CONFIG_OBJTOOL
+
+#ifndef __ASSEMBLY__
+
+#define __ASM_ANNOTATE(section, label, type) \
+ ".pushsection " section ",\"M\", @progbits, 8\n\t" \
+ ".long " __stringify(label) " - .\n\t" \
+ ".long " __stringify(type) "\n\t" \
+ ".popsection\n\t"
+
+#define ASM_ANNOTATE_LABEL(label, type) \
+ __ASM_ANNOTATE(".discard.annotate_insn", label, type)
+
+#define ASM_ANNOTATE(type) \
+ "911:\n\t" \
+ ASM_ANNOTATE_LABEL(911b, type)
+
+#define ASM_ANNOTATE_DATA(type) \
+ "912:\n\t" \
+ __ASM_ANNOTATE(".discard.annotate_data", 912b, type)
+
+#else /* __ASSEMBLY__ */
+
+.macro __ANNOTATE section, type
+.Lhere_\@:
+ .pushsection \section, "M", @progbits, 8
+ .long .Lhere_\@ - .
+ .long \type
+ .popsection
+.endm
+
+.macro ANNOTATE type
+ __ANNOTATE ".discard.annotate_insn", \type
+.endm
+
+.macro ANNOTATE_DATA type
+ __ANNOTATE ".discard.annotate_data", \type
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#else /* !CONFIG_OBJTOOL */
+#ifndef __ASSEMBLY__
+#define ASM_ANNOTATE_LABEL(label, type) ""
+#define ASM_ANNOTATE(type)
+#define ASM_ANNOTATE_DATA(type)
+#else /* __ASSEMBLY__ */
+.macro ANNOTATE type
+.endm
+.macro ANNOTATE_DATA type
+.endm
+#endif /* __ASSEMBLY__ */
+#endif /* !CONFIG_OBJTOOL */
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Annotate away the various 'relocation to !ENDBR` complaints; knowing that
+ * these relocations will never be used for indirect calls.
+ */
+#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
+#define ANNOTATE_NOENDBR_SYM(sym) asm(ASM_ANNOTATE_LABEL(sym, ANNOTYPE_NOENDBR))
+
+/*
+ * This should be used immediately before an indirect jump/call. It tells
+ * objtool the subsequent indirect jump/call is vouched safe for retpoline
+ * builds.
+ */
+#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
+/*
+ * See linux/instrumentation.h
+ */
+#define ANNOTATE_INSTR_BEGIN(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_INSTR_BEGIN)
+#define ANNOTATE_INSTR_END(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_INSTR_END)
+/*
+ * objtool annotation to ignore the alternatives and only consider the original
+ * instruction(s).
+ */
+#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
+/*
+ * This macro indicates that the following intra-function call is valid.
+ * Any non-annotated intra-function call will cause objtool to issue a warning.
+ */
+#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
+/*
+ * Use objtool to validate the entry requirement that all code paths do
+ * VALIDATE_UNRET_END before RET.
+ *
+ * NOTE: The macro must be used at the beginning of a global symbol, otherwise
+ * it will be ignored.
+ */
+#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)
+/*
+ * This should be used to refer to an instruction that is considered
+ * terminating, like a noreturn CALL or UD2 when we know they are not -- eg
+ * WARN using UD2.
+ */
+#define ANNOTATE_REACHABLE(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_REACHABLE)
+/*
+ * This should not be used; it annotates away CFI violations. There are a few
+ * valid use cases like kexec handover to the next kernel image, and there is
+ * no security concern there.
+ *
+ * There are also a few real issues annotated away, like EFI because we can't
+ * control the EFI code.
+ */
+#define ANNOTATE_NOCFI_SYM(sym) asm(ASM_ANNOTATE_LABEL(sym, ANNOTYPE_NOCFI))
+
+/*
+ * Annotate a special section entry. This emables livepatch module generation
+ * to find and extract individual special section entries as needed.
+ */
+#define ANNOTATE_DATA_SPECIAL ASM_ANNOTATE_DATA(ANNOTYPE_DATA_SPECIAL)
+
+#else /* __ASSEMBLY__ */
+#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
+#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
+/* ANNOTATE_INSTR_BEGIN ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
+/* ANNOTATE_INSTR_END ANNOTATE type=ANNOTYPE_INSTR_END */
+#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
+#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
+#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
+#define ANNOTATE_REACHABLE ANNOTATE type=ANNOTYPE_REACHABLE
+#define ANNOTATE_NOCFI_SYM ANNOTATE type=ANNOTYPE_NOCFI
+#define ANNOTATE_DATA_SPECIAL ANNOTATE_DATA type=ANNOTYPE_DATA_SPECIAL
+#endif /* __ASSEMBLY__ */
+
+#endif /* _LINUX_ANNOTATE_H */
diff --git a/include/linux/interval_tree.h b/include/linux/interval_tree.h
index 2b8026a399064..9d5791e9f737a 100644
--- a/include/linux/interval_tree.h
+++ b/include/linux/interval_tree.h
@@ -19,6 +19,10 @@ extern void
interval_tree_remove(struct interval_tree_node *node,
struct rb_root_cached *root);
+extern struct interval_tree_node *
+interval_tree_subtree_search(struct interval_tree_node *node,
+ unsigned long start, unsigned long last);
+
extern struct interval_tree_node *
interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
diff --git a/include/linux/interval_tree_generic.h b/include/linux/interval_tree_generic.h
index 1b400f26f63d6..c5a2fed49eb0d 100644
--- a/include/linux/interval_tree_generic.h
+++ b/include/linux/interval_tree_generic.h
@@ -77,7 +77,7 @@ ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, \
* Cond2: start <= ITLAST(node) \
*/ \
\
-static ITSTRUCT * \
+ITSTATIC ITSTRUCT * \
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
while (true) { \
diff --git a/include/linux/livepatch_helpers.h b/include/linux/livepatch_helpers.h
index 337bee91d7daf..99d68d0773fa8 100644
--- a/include/linux/livepatch_helpers.h
+++ b/include/linux/livepatch_helpers.h
@@ -36,8 +36,6 @@
__PASTE(__KLP_POST_UNPATCH_PREFIX, KLP_OBJNAME) = func
/*
- * KLP_STATIC_CALL
- *
* Replace static_call() usage with this macro when create-diff-object
* recommends it due to the original static call key living in a module.
*
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1ae97a0b8ec75..69baa9a1e2cb4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3265,6 +3265,8 @@ void vma_interval_tree_insert_after(struct vm_area_struct *node,
struct rb_root_cached *root);
void vma_interval_tree_remove(struct vm_area_struct *node,
struct rb_root_cached *root);
+struct vm_area_struct *vma_interval_tree_subtree_search(struct vm_area_struct *node,
+ unsigned long start, unsigned long last);
struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index b5081aea3b69d..b18ab53561c99 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -2,22 +2,17 @@
#ifndef _LINUX_OBJTOOL_H
#define _LINUX_OBJTOOL_H
-#ifndef COMPILE_OFFSETS
-#include <generated/bounds.h>
-#endif
-
#include <linux/objtool_types.h>
+#include <linux/annotate.h>
#ifdef CONFIG_OBJTOOL
-#include <asm/asm.h>
-
#ifndef __ASSEMBLY__
#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
"987: \n\t" \
- ".pushsection .discard.unwind_hints, \"M\", @progbits, "\
- __stringify(UNWIND_HINT_SIZE) "\n\t" \
+ ".pushsection .discard.unwind_hints\n\t" \
+ ANNOTATE_DATA_SPECIAL \
/* struct unwind_hint */ \
".long 987b - .\n\t" \
".short " __stringify(sp_offset) "\n\t" \
@@ -58,16 +53,6 @@
#define __ASM_BREF(label) label ## b
-#define __ASM_ANNOTATE(label, type) \
- ".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \
- ".long " __stringify(label) " - .\n\t" \
- ".long " __stringify(type) "\n\t" \
- ".popsection\n\t"
-
-#define ASM_ANNOTATE(type) \
- "911:\n\t" \
- __ASM_ANNOTATE(911b, type)
-
#else /* __ASSEMBLY__ */
/*
@@ -93,7 +78,8 @@
*/
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.Lhere_\@:
- .pushsection .discard.unwind_hints, "M", @progbits, UNWIND_HINT_SIZE
+ .pushsection .discard.unwind_hints
+ ANNOTATE_DATA_SPECIAL
/* struct unwind_hint */
.long .Lhere_\@ - .
.short \sp_offset
@@ -116,14 +102,6 @@
#endif
.endm
-.macro ANNOTATE type:req
-.Lhere_\@:
- .pushsection .discard.annotate_insn,"M",@progbits,8
- .long .Lhere_\@ - .
- .long \type
- .popsection
-.endm
-
#endif /* __ASSEMBLY__ */
#else /* !CONFIG_OBJTOOL */
@@ -133,84 +111,15 @@
#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t"
#define STACK_FRAME_NON_STANDARD(func)
#define STACK_FRAME_NON_STANDARD_FP(func)
-#define __ASM_ANNOTATE(label, type) ""
-#define ASM_ANNOTATE(type)
#else
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
-.macro ANNOTATE type:req
-.endm
#endif
#endif /* CONFIG_OBJTOOL */
-#ifndef __ASSEMBLY__
-/*
- * Annotate away the various 'relocation to !ENDBR` complaints; knowing that
- * these relocations will never be used for indirect calls.
- */
-#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
-#define ANNOTATE_NOENDBR_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOENDBR))
-
-/*
- * This should be used immediately before an indirect jump/call. It tells
- * objtool the subsequent indirect jump/call is vouched safe for retpoline
- * builds.
- */
-#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
-/*
- * See linux/instrumentation.h
- */
-#define ANNOTATE_INSTR_BEGIN(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_BEGIN)
-#define ANNOTATE_INSTR_END(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_END)
-/*
- * objtool annotation to ignore the alternatives and only consider the original
- * instruction(s).
- */
-#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
-/*
- * This macro indicates that the following intra-function call is valid.
- * Any non-annotated intra-function call will cause objtool to issue a warning.
- */
-#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
-/*
- * Use objtool to validate the entry requirement that all code paths do
- * VALIDATE_UNRET_END before RET.
- *
- * NOTE: The macro must be used at the beginning of a global symbol, otherwise
- * it will be ignored.
- */
-#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)
-/*
- * This should be used to refer to an instruction that is considered
- * terminating, like a noreturn CALL or UD2 when we know they are not -- eg
- * WARN using UD2.
- */
-#define ANNOTATE_REACHABLE(label) __ASM_ANNOTATE(label, ANNOTYPE_REACHABLE)
-/*
- * This should not be used; it annotates away CFI violations. There are a few
- * valid use cases like kexec handover to the next kernel image, and there is
- * no security concern there.
- *
- * There are also a few real issues annotated away, like EFI because we can't
- * control the EFI code.
- */
-#define ANNOTATE_NOCFI_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOCFI))
-
-#else
-#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
-#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
-/* ANNOTATE_INSTR_BEGIN ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
-/* ANNOTATE_INSTR_END ANNOTATE type=ANNOTYPE_INSTR_END */
-#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
-#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
-#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
-#define ANNOTATE_REACHABLE ANNOTATE type=ANNOTYPE_REACHABLE
-#define ANNOTATE_NOCFI_SYM ANNOTATE type=ANNOTYPE_NOCFI
-#endif
-
#if defined(CONFIG_NOINSTR_VALIDATION) && \
(defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
#define VALIDATE_UNRET_BEGIN ANNOTATE_UNRET_BEGIN
diff --git a/include/linux/objtool_types.h b/include/linux/objtool_types.h
index aceac94632c8a..c6def4049b1ae 100644
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -67,4 +67,6 @@ struct unwind_hint {
#define ANNOTYPE_REACHABLE 8
#define ANNOTYPE_NOCFI 9
+#define ANNOTYPE_DATA_SPECIAL 1
+
#endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/include/linux/static_call.h b/include/linux/static_call.h
index 5210612817f2e..78a77a4ae0ea8 100644
--- a/include/linux/static_call.h
+++ b/include/linux/static_call.h
@@ -172,6 +172,12 @@ struct static_call_mod {
struct static_call_site *sites;
};
+/* For finding the key associated with a trampoline */
+struct static_call_tramp_key {
+ s32 tramp;
+ s32 key;
+};
+
extern void __static_call_update(struct static_call_key *key, void *tramp, void *func);
extern int static_call_mod_init(struct module *mod);
extern int static_call_text_reserved(void *start, void *end);
diff --git a/include/linux/static_call_types.h b/include/linux/static_call_types.h
index eb772df625d4e..5a00b8b2cf9fc 100644
--- a/include/linux/static_call_types.h
+++ b/include/linux/static_call_types.h
@@ -34,12 +34,6 @@ struct static_call_site {
s32 key;
};
-/* For finding the key associated with a trampoline */
-struct static_call_tramp_key {
- s32 tramp;
- s32 key;
-};
-
#define DECLARE_STATIC_CALL(name, func) \
extern struct static_call_key STATIC_CALL_KEY(name); \
extern typeof(func) STATIC_CALL_TRAMP(name);
diff --git a/kernel/bounds.c b/kernel/bounds.c
index f9bc13727721e..29b2cd00df2cc 100644
--- a/kernel/bounds.c
+++ b/kernel/bounds.c
@@ -6,16 +6,12 @@
*/
#define __GENERATING_BOUNDS_H
-#define COMPILE_OFFSETS
/* Include headers that define the enum constants of interest */
#include <linux/page-flags.h>
#include <linux/mmzone.h>
#include <linux/kbuild.h>
#include <linux/log2.h>
#include <linux/spinlock_types.h>
-#include <linux/jump_label.h>
-#include <linux/static_call_types.h>
-#include <linux/objtool_types.h>
int main(void)
{
@@ -32,15 +28,6 @@ int main(void)
#else
DEFINE(LRU_GEN_WIDTH, 0);
DEFINE(__LRU_REFS_WIDTH, 0);
-#endif
-#if defined(CONFIG_HAVE_ARCH_JUMP_LABEL_RELATIVE) && defined(CONFIG_JUMP_LABEL)
- DEFINE(JUMP_ENTRY_SIZE, sizeof(struct jump_entry));
-#endif
-#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
- DEFINE(STATIC_CALL_TRAMP_KEY_SIZE, sizeof(struct static_call_tramp_key));
-#endif
-#ifdef CONFIG_OBJTOOL
- DEFINE(UNWIND_HINT_SIZE, sizeof(struct unwind_hint));
#endif
/* End of constants */
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 28a1c08e3b221..f4b33919ec371 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -173,6 +173,7 @@ ifdef CONFIG_OBJTOOL
objtool := $(objtree)/tools/objtool/objtool
+objtool-args-$(CONFIG_KLP_BUILD) += --checksum
objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK) += --hacks=jump_label
objtool-args-$(CONFIG_HAVE_NOINSTR_HACK) += --hacks=noinstr
objtool-args-$(CONFIG_MITIGATION_CALL_DEPTH_TRACKING) += --hacks=skylake
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 7a888e1ff70f2..542ba462ed3ec 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -28,24 +28,12 @@ ccflags-remove-y := $(CC_FLAGS_CFI)
.module-common.o: $(srctree)/scripts/module-common.c FORCE
$(call if_changed_rule,cc_o_c)
-ifdef CONFIG_NEED_MODULE_PERMISSIONS_FIX
-cmd_fix_mod_permissions = \
- $(OBJCOPY) --set-section-flags __jump_table=alloc,data \
- --set-section-flags __bug_table=alloc,data $@ \
- --set-section-flags .static_call_sites=alloc,data $@
-endif
-
quiet_cmd_ld_ko_o = LD [M] $@
cmd_ld_ko_o = \
$(LD) -r $(KBUILD_LDFLAGS) \
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
-T $(objtree)/scripts/module.lds -o $@ $(filter %.o, $^)
-define rule_ld_ko_o
- $(call cmd_and_savecmd,ld_ko_o)
- $(call cmd,fix_mod_permissions)
-endef
-
quiet_cmd_btf_ko = BTF [M] $@
cmd_btf_ko = \
if [ ! -f $(objtree)/vmlinux ]; then \
@@ -58,11 +46,14 @@ quiet_cmd_btf_ko = BTF [M] $@
# Same as newer-prereqs, but allows to exclude specified extra dependencies
newer_prereqs_except = $(filter-out $(PHONY) $(1),$?)
-if_changed_rule_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check),$(rule_$(1)),@:)
+# Same as if_changed, but allows to exclude specified extra dependencies
+if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \
+ $(cmd); \
+ printf '%s\n' 'savedcmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
# Re-generate module BTFs if either module's .ko or vmlinux changed
%.ko: %.o %.mod.o .module-common.o $(objtree)/scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),$(objtree)/vmlinux) FORCE
- +$(call if_changed_rule_except,ld_ko_o,$(objtree)/vmlinux)
+ +$(call if_changed_except,ld_ko_o,$(objtree)/vmlinux)
ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+$(if $(newer-prereqs),$(call cmd,btf_ko))
endif
diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index e47056f75475e..881e052e7faef 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -489,11 +489,8 @@ clean_kernel() {
build_kernel() {
local log="$TMP_DIR/build.log"
- local objtool_args=()
local cmd=()
- objtool_args=("--checksum")
-
cmd=("make")
# When a patch to a kernel module references a newly created unexported
@@ -516,7 +513,6 @@ build_kernel() {
cmd+=("$VERBOSE")
cmd+=("-j$JOBS")
cmd+=("KCFLAGS=-ffunction-sections -fdata-sections")
- cmd+=("OBJTOOL_ARGS=${objtool_args[*]}")
cmd+=("vmlinux")
cmd+=("modules")
@@ -794,7 +790,7 @@ process_args "$@"
do_init
if (( SHORT_CIRCUIT <= 1 )); then
- status "Validating patches"
+ status "Validating patch(es)"
validate_patches
status "Building original kernel"
clean_kernel
@@ -804,7 +800,7 @@ if (( SHORT_CIRCUIT <= 1 )); then
fi
if (( SHORT_CIRCUIT <= 2 )); then
- status "Fixing patches"
+ status "Fixing patch(es)"
fix_patches
apply_patches
status "Building patched kernel"
diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
index ef2ffb68f69d1..d3d00e85edf73 100644
--- a/scripts/mod/devicetable-offsets.c
+++ b/scripts/mod/devicetable-offsets.c
@@ -1,5 +1,4 @@
// SPDX-License-Identifier: GPL-2.0
-#define COMPILE_OFFSETS
#include <linux/kbuild.h>
#include <linux/mod_devicetable.h>
diff --git a/tools/include/linux/interval_tree_generic.h b/tools/include/linux/interval_tree_generic.h
index c0ec9dbdfbaf2..c5a2fed49eb0d 100644
--- a/tools/include/linux/interval_tree_generic.h
+++ b/tools/include/linux/interval_tree_generic.h
@@ -104,12 +104,8 @@ ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
if (ITSTART(node) <= last) { /* Cond1 */ \
if (start <= ITLAST(node)) /* Cond2 */ \
return node; /* node is leftmost match */ \
- if (node->ITRB.rb_right) { \
- node = rb_entry(node->ITRB.rb_right, \
- ITSTRUCT, ITRB); \
- if (start <= node->ITSUBTREE) \
- continue; \
- } \
+ node = rb_entry(node->ITRB.rb_right, ITSTRUCT, ITRB); \
+ continue; \
} \
return NULL; /* No match */ \
} \
diff --git a/tools/include/linux/objtool_types.h b/tools/include/linux/objtool_types.h
index aceac94632c8a..c6def4049b1ae 100644
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -67,4 +67,6 @@ struct unwind_hint {
#define ANNOTYPE_REACHABLE 8
#define ANNOTYPE_NOCFI 9
+#define ANNOTYPE_DATA_SPECIAL 1
+
#endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/tools/include/linux/static_call_types.h b/tools/include/linux/static_call_types.h
index eb772df625d4e..5a00b8b2cf9fc 100644
--- a/tools/include/linux/static_call_types.h
+++ b/tools/include/linux/static_call_types.h
@@ -34,12 +34,6 @@ struct static_call_site {
s32 key;
};
-/* For finding the key associated with a trampoline */
-struct static_call_tramp_key {
- s32 tramp;
- s32 key;
-};
-
#define DECLARE_STATIC_CALL(name, func) \
extern struct static_call_key STATIC_CALL_KEY(name); \
extern typeof(func) STATIC_CALL_TRAMP(name);
diff --git a/tools/objtool/arch/loongarch/orc.c b/tools/objtool/arch/loongarch/orc.c
index b58c5ff443c92..ffd3a3c858ae7 100644
--- a/tools/objtool/arch/loongarch/orc.c
+++ b/tools/objtool/arch/loongarch/orc.c
@@ -5,7 +5,6 @@
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
{
diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
index d4cb02120a6bd..3a9b748216edc 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -7,7 +7,6 @@
#include <objtool/arch.h>
#include <objtool/warn.h>
#include <objtool/builtin.h>
-#include <objtool/endianness.h>
int arch_ftrace_match(const char *name)
{
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 6f3aa117027a6..5c72beeaa3a71 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -19,7 +19,6 @@
#include <objtool/elf.h>
#include <objtool/arch.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
#include <objtool/builtin.h>
#include <arch/elf.h>
diff --git a/tools/objtool/arch/x86/orc.c b/tools/objtool/arch/x86/orc.c
index 7176b9ec5b058..735e150ca6b73 100644
--- a/tools/objtool/arch/x86/orc.c
+++ b/tools/objtool/arch/x86/orc.c
@@ -5,7 +5,6 @@
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
{
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index c4e45236a561d..b20b0077449b2 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -74,7 +74,7 @@ static int parse_hacks(const struct option *opt, const char *str, int unset)
static const struct option check_options[] = {
OPT_GROUP("Actions:"),
OPT_BOOLEAN(0, "checksum", &opts.checksum, "generate per-function checksums"),
- OPT_BOOLEAN(0 , "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
+ OPT_BOOLEAN(0, "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
@@ -162,7 +162,6 @@ static bool opts_valid(void)
return false;
}
-
#ifndef BUILD_KLP
if (opts.checksum) {
ERROR("--checksum not supported; install xxhash-devel and recompile");
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2f0c86ba14a5c..ba591a325d52e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -15,8 +15,8 @@
#include <objtool/check.h>
#include <objtool/special.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
#include <objtool/checksum.h>
+#include <objtool/util.h>
#include <linux/objtool_types.h>
#include <linux/hashtable.h>
@@ -660,15 +660,8 @@ static int create_static_call_sections(struct objtool_file *file)
if (!sec)
return -1;
- /*
- * Set SHF_MERGE to prevent tooling from stripping entsize.
- *
- * SHF_WRITE would also get set here to allow modules to modify the low
- * bits of static_call_site::key, but the LLVM linker doesn't allow
- * SHF_MERGE+SHF_WRITE for whatever reason. That gets fixed up by the
- * makefiles with CONFIG_NEED_MODULE_PERMISSIONS_FIX.
- */
- sec->sh.sh_flags |= SHF_MERGE;
+ /* Allow modules to modify the low bits of static_call_site::key */
+ sec->sh.sh_flags |= SHF_WRITE;
idx = 0;
list_for_each_entry(insn, &file->static_call_list, call_node) {
@@ -1003,10 +996,10 @@ static int create_sym_checksum_section(struct objtool_file *file)
struct sym_checksum *checksum;
size_t entsize = sizeof(struct sym_checksum);
- sec = find_section_by_name(file->elf, SYM_CHECKSUM_SEC);
+ sec = find_section_by_name(file->elf, ".discard.sym_checksum");
if (sec) {
if (!opts.dryrun)
- WARN("file already has " SYM_CHECKSUM_SEC " section, skipping");
+ WARN("file already has .discard.sym_checksum section, skipping");
return 0;
}
@@ -2349,9 +2342,7 @@ static int read_annotate(struct objtool_file *file,
}
for_each_reloc(sec->rsec, reloc) {
- type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4);
- type = bswap_if_needed(file->elf, type);
-
+ type = annotype(file->elf, sec, reloc);
offset = reloc->sym->offset + reloc_addend(reloc);
insn = find_insn(file, reloc->sym->sec, offset);
@@ -4283,48 +4274,82 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
return false;
}
-static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
+/*
+ * For FineIBT or kCFI, a certain number of bytes preceding the function may be
+ * NOPs. Those NOPs may be rewritten at runtime and executed, so give them a
+ * proper function name: __pfx_<func>.
+ *
+ * The NOPs may not exist for the following cases:
+ *
+ * - compiler cloned functions (*.cold, *.part0, etc)
+ * - asm functions created with inline asm or without SYM_FUNC_START()
+ *
+ * Also, the function may already have a prefix from a previous objtool run
+ * (livepatch extracted functions, or manually running objtool multiple times).
+ *
+ * So return 0 if the NOPs are missing or the function already has a prefix
+ * symbol.
+ */
+static int create_prefix_symbol(struct objtool_file *file, struct symbol *func)
{
struct instruction *insn, *prev;
+ char name[SYM_NAME_LEN];
struct cfi_state *cfi;
- insn = find_insn(file, func->sec, func->offset);
- if (!insn)
+ if (!is_func_sym(func) || is_prefix_func(func) ||
+ func->cold || func->static_call_tramp)
+ return 0;
+
+ if ((strlen(func->name) + sizeof("__pfx_") > SYM_NAME_LEN)) {
+ WARN("%s: symbol name too long, can't create __pfx_ symbol",
+ func->name);
+ return 0;
+ }
+
+ if (snprintf_check(name, SYM_NAME_LEN, "__pfx_%s", func->name))
return -1;
+ if (file->klp) {
+ struct symbol *pfx;
+
+ pfx = find_symbol_by_offset(func->sec, func->offset - opts.prefix);
+ if (pfx && is_prefix_func(pfx) && !strcmp(pfx->name, name))
+ return 0;
+ }
+
+ insn = find_insn(file, func->sec, func->offset);
+ if (!insn) {
+ WARN("%s: can't find starting instruction", func->name);
+ return -1;
+ }
+
for (prev = prev_insn_same_sec(file, insn);
prev;
prev = prev_insn_same_sec(file, prev)) {
- struct symbol *sym_pfx;
u64 offset;
if (prev->type != INSN_NOP)
- return -1;
+ return 0;
offset = func->offset - prev->offset;
if (offset > opts.prefix)
- return -1;
+ return 0;
if (offset < opts.prefix)
continue;
- /*
- * Ignore attempts to make duplicate symbols in livepatch
- * modules. They've already extracted the prefix symbols
- * except for the newly compiled init.c.
- */
- sym_pfx = elf_create_prefix_symbol(file->elf, func, opts.prefix);
- if (!sym_pfx && !file->klp) {
- WARN("duplicate prefix symbol for %s\n", func->name);
+ if (!elf_create_symbol(file->elf, name, func->sec,
+ GELF_ST_BIND(func->sym.st_info),
+ GELF_ST_TYPE(func->sym.st_info),
+ prev->offset, opts.prefix))
return -1;
- }
break;
}
if (!prev)
- return -1;
+ return 0;
if (!insn->cfi) {
/*
@@ -4342,7 +4367,7 @@ static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
return 0;
}
-static int add_prefix_symbols(struct objtool_file *file)
+static int create_prefix_symbols(struct objtool_file *file)
{
struct section *sec;
struct symbol *func;
@@ -4352,14 +4377,8 @@ static int add_prefix_symbols(struct objtool_file *file)
continue;
sec_for_each_sym(sec, func) {
- if (!is_func_sym(func))
- continue;
-
- /*
- * Ignore this error on purpose, there are valid
- * reasons for this to fail.
- */
- add_prefix_symbol(file, func);
+ if (create_prefix_symbol(file, func))
+ return -1;
}
}
@@ -4987,7 +5006,7 @@ int check(struct objtool_file *file)
}
if (opts.prefix) {
- ret = add_prefix_symbols(file);
+ ret = create_prefix_symbols(file);
if (ret)
goto out;
}
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 2551a5727949f..5feeefc7fc8f8 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -945,32 +945,6 @@ struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec)
return sym;
}
-struct symbol *
-elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, size_t size)
-{
- size_t namelen = strlen(orig->name) + sizeof("__pfx_");
- char name[SYM_NAME_LEN];
- unsigned long offset;
- struct symbol *sym;
-
- snprintf(name, namelen, "__pfx_%s", orig->name);
-
- sym = orig;
- offset = orig->sym.st_value - size;
-
- sec_for_each_sym_continue_reverse(orig->sec, sym) {
- if (sym->offset < offset)
- break;
- if (sym->offset == offset && !strcmp(sym->name, name))
- return NULL;
- }
-
- return elf_create_symbol(elf, name, orig->sec,
- GELF_ST_BIND(orig->sym.st_info),
- GELF_ST_TYPE(orig->sym.st_info),
- offset, size);
-}
-
struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
unsigned int reloc_idx, unsigned long offset,
struct symbol *sym, s64 addend, unsigned int type)
@@ -1075,8 +1049,10 @@ static int read_relocs(struct elf *elf)
rsec->base->rsec = rsec;
- rsec->nr_alloc_relocs = sec_num_entries(rsec);
- rsec->relocs = calloc(rsec->nr_alloc_relocs, sizeof(*reloc));
+ /* nr_alloc_relocs=0: libelf owns d_buf */
+ rsec->nr_alloc_relocs = 0;
+
+ rsec->relocs = calloc(sec_num_entries(rsec), sizeof(*reloc));
if (!rsec->relocs) {
ERROR_GLIBC("calloc");
return -1;
@@ -1496,15 +1472,32 @@ static int elf_alloc_reloc(struct elf *elf, struct section *rsec)
nr_alloc = MAX(64, ALIGN_UP_POW2(nr_relocs_new));
if (nr_alloc <= rsec->nr_alloc_relocs)
return 0;
- rsec->nr_alloc_relocs = nr_alloc;
- rsec->data->d_buf = realloc(rsec->data->d_buf,
- nr_alloc * elf_rela_size(elf));
- if (!rsec->data->d_buf) {
- ERROR_GLIBC("realloc");
- return -1;
+ if (rsec->data->d_buf && !rsec->nr_alloc_relocs) {
+ void *orig_buf = rsec->data->d_buf;
+
+ /*
+ * The original d_buf is owned by libelf so it can't be
+ * realloced.
+ */
+ rsec->data->d_buf = malloc(nr_alloc * elf_rela_size(elf));
+ if (!rsec->data->d_buf) {
+ ERROR_GLIBC("malloc");
+ return -1;
+ }
+ memcpy(rsec->data->d_buf, orig_buf,
+ nr_relocs_old * elf_rela_size(elf));
+ } else {
+ rsec->data->d_buf = realloc(rsec->data->d_buf,
+ nr_alloc * elf_rela_size(elf));
+ if (!rsec->data->d_buf) {
+ ERROR_GLIBC("realloc");
+ return -1;
+ }
}
+ rsec->nr_alloc_relocs = nr_alloc;
+
old_relocs = rsec->relocs;
new_relocs = calloc(nr_alloc, sizeof(struct reloc));
if (!new_relocs) {
@@ -1623,6 +1616,8 @@ struct reloc *elf_create_reloc(struct elf *elf, struct section *sec,
if (elf_alloc_reloc(elf, rsec))
return NULL;
+ mark_sec_changed(elf, rsec, true);
+
return elf_init_reloc(elf, rsec, sec_num_entries(rsec) - 1, offset, sym,
addend, type);
}
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index 8a0d42aa4d858..bb0b25eb08ba4 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -10,6 +10,7 @@
struct opts {
/* actions: */
bool cfi;
+ bool checksum;
bool dump_orc;
bool hack_jump_label;
bool hack_noinstr;
@@ -25,7 +26,6 @@ struct opts {
bool sls;
bool stackval;
bool static_call;
- bool checksum;
bool uaccess;
int prefix;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 64e75ade01c90..21d8b825fd8f0 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -14,12 +14,15 @@
#include <linux/rbtree.h>
#include <linux/jhash.h>
+#include <objtool/endianness.h>
#include <objtool/checksum_types.h>
#include <arch/elf.h>
#define SEC_NAME_LEN 1024
#define SYM_NAME_LEN 512
+#define bswap_if_needed(elf, val) __bswap_if_needed(&elf->ehdr, val)
+
#ifdef LIBELF_USE_DEPRECATED
# define elf_getshdrnum elf_getshnum
# define elf_getshdrstrndx elf_getshstrndx
@@ -146,8 +149,6 @@ struct symbol *elf_create_symbol(struct elf *elf, const char *name,
unsigned int type, unsigned long offset,
size_t size);
struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec);
-struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,
- size_t size);
void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
size_t size);
@@ -274,7 +275,7 @@ static inline bool is_local_sym(struct symbol *sym)
static inline bool is_prefix_func(struct symbol *sym)
{
- return is_func_sym(sym) && sym->prefix;
+ return sym->prefix;
}
static inline bool is_reloc_sec(struct section *sec)
@@ -414,6 +415,15 @@ static inline void set_reloc_type(struct elf *elf, struct reloc *reloc, unsigned
mark_sec_changed(elf, reloc->sec, true);
}
+static inline unsigned int annotype(struct elf *elf, struct section *sec,
+ struct reloc *reloc)
+{
+ unsigned int type;
+
+ type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * 8) + 4);
+ return bswap_if_needed(elf, type);
+}
+
#define RELOC_JUMP_TABLE_BIT 1UL
/* Does reloc mark the beginning of a jump table? */
@@ -445,9 +455,6 @@ static inline void set_sym_next_reloc(struct reloc *reloc, struct reloc *next)
#define sec_for_each_sym(sec, sym) \
list_for_each_entry(sym, &sec->symbol_list, list)
-#define sec_for_each_sym_continue_reverse(sec, sym) \
- list_for_each_entry_continue_reverse(sym, &sec->symbol_list, list)
-
#define sec_prev_sym(sym) \
sym->sec && sym->list.prev != &sym->sec->symbol_list ? \
list_prev_entry(sym, list) : NULL
@@ -467,6 +474,10 @@ static inline void set_sym_next_reloc(struct reloc *reloc, struct reloc *next)
#define for_each_reloc_from(rsec, reloc) \
for (; reloc; reloc = rsec_next_reloc(rsec, reloc))
+#define for_each_reloc_continue(rsec, reloc) \
+ for (reloc = rsec_next_reloc(rsec, reloc); reloc; \
+ reloc = rsec_next_reloc(rsec, reloc))
+
#define sym_for_each_reloc(elf, sym, reloc) \
for (reloc = find_reloc_by_dest_range(elf, sym->sec, \
sym->offset, sym->len); \
diff --git a/tools/objtool/include/objtool/endianness.h b/tools/objtool/include/objtool/endianness.h
index 4d2aa9b0fe2fd..aebcd23386685 100644
--- a/tools/objtool/include/objtool/endianness.h
+++ b/tools/objtool/include/objtool/endianness.h
@@ -4,7 +4,6 @@
#include <linux/kernel.h>
#include <endian.h>
-#include <objtool/elf.h>
/*
* Does a byte swap if target file endianness doesn't match the host, i.e. cross
@@ -12,16 +11,16 @@
* To be used for multi-byte values conversion, which are read from / about
* to be written to a target native endianness ELF file.
*/
-static inline bool need_bswap(struct elf *elf)
+static inline bool need_bswap(GElf_Ehdr *ehdr)
{
return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
- (elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
+ (ehdr->e_ident[EI_DATA] == ELFDATA2LSB);
}
-#define bswap_if_needed(elf, val) \
+#define __bswap_if_needed(ehdr, val) \
({ \
__typeof__(val) __ret; \
- bool __need_bswap = need_bswap(elf); \
+ bool __need_bswap = need_bswap(ehdr); \
switch (sizeof(val)) { \
case 8: \
__ret = __need_bswap ? bswap_64(val) : (val); break; \
diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h
index 731965a742e99..f7051bbe0bcb2 100644
--- a/tools/objtool/include/objtool/objtool.h
+++ b/tools/objtool/include/objtool/objtool.h
@@ -14,8 +14,6 @@
#define __weak __attribute__((weak))
-#define SYM_CHECKSUM_SEC ".discard.sym_checksum"
-
struct pv_state {
bool clean;
struct list_head targets;
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 15b554b53da63..4d1f9e9977eb9 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -14,6 +14,7 @@
#include <objtool/util.h>
#include <arch/special.h>
+#include <linux/objtool_types.h>
#include <linux/livepatch_external.h>
#include <linux/stringify.h>
#include <linux/string.h>
@@ -167,15 +168,15 @@ static int read_sym_checksums(struct elf *elf)
{
struct section *sec;
- sec = find_section_by_name(elf, SYM_CHECKSUM_SEC);
+ sec = find_section_by_name(elf, ".discard.sym_checksum");
if (!sec) {
- ERROR("'%s' missing " SYM_CHECKSUM_SEC " section, file not processed by 'objtool --checksum'?",
+ ERROR("'%s' missing .discard.sym_checksum section, file not processed by 'objtool --checksum'?",
elf->name);
return -1;
}
if (!sec->rsec) {
- ERROR("missing reloc section for " SYM_CHECKSUM_SEC);
+ ERROR("missing reloc section for .discard.sym_checksum");
return -1;
}
@@ -297,7 +298,7 @@ static bool is_special_section(struct section *sec)
static const char * const non_special_discards[] = {
".discard.addressable",
- SYM_CHECKSUM_SEC,
+ ".discard.sym_checksum",
};
if (is_text_sec(sec))
@@ -1150,6 +1151,135 @@ static int clone_sym_relocs(struct elfs *e, struct symbol *patched_sym)
}
+static int create_fake_symbol(struct elf *elf, struct section *sec,
+ unsigned long offset, size_t size)
+{
+ char name[SYM_NAME_LEN];
+ unsigned int type;
+ static int ctr;
+ char *c;
+
+ if (snprintf_check(name, SYM_NAME_LEN, "%s_%d", sec->name, ctr++))
+ return -1;
+
+ for (c = name; *c; c++)
+ if (*c == '.')
+ *c = '_';
+
+ /*
+ * STT_NOTYPE: Prevent objtool from validating .altinstr_replacement
+ * while still allowing objdump to disassemble it.
+ */
+ type = is_text_sec(sec) ? STT_NOTYPE : STT_OBJECT;
+ return elf_create_symbol(elf, name, sec, STB_LOCAL, type, offset, size) ? 0 : -1;
+}
+
+/*
+ * Special sections (alternatives, etc) are basically arrays of structs.
+ * For all the special sections, create a symbol for each struct entry. This
+ * is a bit cumbersome, but it makes the extracting of the individual entries
+ * much more straightforward.
+ *
+ * There are three ways to identify the entry sizes for a special section:
+ *
+ * 1) ELF section header sh_entsize: Ideally this would be used almost
+ * everywhere. But unfortunately the toolchains make it difficult. The
+ * assembler .[push]section directive syntax only takes entsize when
+ * combined with SHF_MERGE. But Clang disallows combining SHF_MERGE with
+ * SHF_WRITE. And some special sections do need to be writable.
+ *
+ * Another place this wouldn't work is .altinstr_replacement, whose entries
+ * don't have a fixed size.
+ *
+ * 2) ANNOTATE_DATA_SPECIAL: This is a lightweight objtool annotation which
+ * points to the beginning of each entry. The size of the entry is then
+ * inferred by the location of the subsequent annotation (or end of
+ * section).
+ *
+ * 3) Simple array of pointers: If the special section is just a basic array of
+ * pointers, the entry size can be inferred by the number of relocations.
+ * No annotations needed.
+ *
+ * Note I also tried to create per-entry symbols at the time of creation, in
+ * the original [inline] asm. Unfortunately, creating uniquely named symbols
+ * is trickier than one might think, especially with Clang inline asm. I
+ * eventually just gave up trying to make that work, in favor of using
+ * ANNOTATE_DATA_SPECIAL and creating the symbols here after the fact.
+ */
+static int create_fake_symbols(struct elf *elf)
+{
+ struct section *sec;
+ struct reloc *reloc;
+
+ /*
+ * 1) Make symbols for all the ANNOTATE_DATA_SPECIAL entries:
+ */
+
+ sec = find_section_by_name(elf, ".discard.annotate_data");
+ if (!sec || !sec->rsec)
+ return 0;
+
+ for_each_reloc(sec->rsec, reloc) {
+ unsigned long offset, size;
+ struct reloc *next_reloc;
+
+ if (annotype(elf, sec, reloc) != ANNOTYPE_DATA_SPECIAL)
+ continue;
+
+ offset = reloc_addend(reloc);
+
+ size = 0;
+ next_reloc = reloc;
+ for_each_reloc_continue(sec->rsec, next_reloc) {
+ if (annotype(elf, sec, next_reloc) != ANNOTYPE_DATA_SPECIAL ||
+ next_reloc->sym->sec != reloc->sym->sec)
+ continue;
+
+ size = reloc_addend(next_reloc) - offset;
+ break;
+ }
+
+ if (!size)
+ size = sec_size(reloc->sym->sec) - offset;
+
+ if (create_fake_symbol(elf, reloc->sym->sec, offset, size))
+ return -1;
+ }
+
+ /*
+ * 2) Make symbols for sh_entsize, and simple arrays of pointers:
+ */
+
+ for_each_sec(elf, sec) {
+ unsigned int entry_size;
+ unsigned long offset;
+
+ if (!is_special_section(sec) || find_symbol_by_offset(sec, 0))
+ continue;
+
+ if (!sec->rsec) {
+ ERROR("%s: missing special section relocations", sec->name);
+ return -1;
+ }
+
+ entry_size = sec->sh.sh_entsize;
+ if (!entry_size) {
+ entry_size = arch_reloc_size(sec->rsec->relocs);
+ if (sec_size(sec) != entry_size * sec_num_entries(sec->rsec)) {
+ ERROR("%s: missing special section entsize or annotations", sec->name);
+ return -1;
+ }
+ }
+
+ for (offset = 0; offset < sec_size(sec); offset += entry_size) {
+ if (create_fake_symbol(elf, sec, offset, entry_size))
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
/* Keep a special section entry if it references an included function */
static bool should_keep_special_sym(struct elf *elf, struct symbol *sym)
{
@@ -1260,99 +1390,12 @@ static int validate_special_section_klp_reloc(struct elfs *e, struct symbol *sym
return ret;
}
-static int special_section_entry_size(struct section *sec)
-{
- unsigned int reloc_size;
-
- if ((sec->sh.sh_flags & SHF_MERGE) && sec->sh.sh_entsize)
- return sec->sh.sh_entsize;
-
- if (!sec->rsec)
- return 0;
-
- /* Check for a simple array of pointers */
- reloc_size = arch_reloc_size(sec->rsec->relocs);
- if (sec_size(sec) == reloc_size * sec_num_entries(sec->rsec))
- return reloc_size;
-
- return 0;
-}
-
-static int create_fake_symbol(struct elf *elf, struct section *sec,
- unsigned long offset, size_t size)
-{
- char name[SYM_NAME_LEN];
- unsigned int type;
- static int ctr;
- char *c;
-
- if (snprintf_check(name, SYM_NAME_LEN, "__DISCARD_%s_%d", sec->name, ctr++))
- return -1;
-
- for (c = name; *c; c++)
- if (*c == '.')
- *c = '_';
-
- /*
- * STT_NOTYPE: Prevent objtool from validating .altinstr_replacement
- * while still allowing objdump to disassemble it.
- */
- type = is_text_sec(sec) ? STT_NOTYPE : STT_OBJECT;
- if (!elf_create_symbol(elf, name, sec, STB_LOCAL, type, offset, size))
- return -1;
-
- return 0;
-}
-
static int clone_special_section(struct elfs *e, struct section *patched_sec)
{
struct symbol *patched_sym;
- unsigned int entry_size;
- unsigned long offset;
-
- entry_size = special_section_entry_size(patched_sec);
- if (!entry_size) {
- /*
- * Any special section more complex than a simple array of
- * pointers must have its entry size specified in sh_entsize
- * (and the SHF_MERGE flag set so the linker preserves it).
- *
- * Clang older than version 20 doesn't properly preserve
- * sh_entsize and will error out here.
- */
- ERROR("%s: buggy linker and/or missing sh_entsize", patched_sec->name);
- return -1;
- }
/*
- * In the patched object, create a fake symbol for each special section
- * entry. This makes the below extracting of entries much easier.
- */
- for (offset = 0; offset < sec_size(patched_sec); offset += entry_size) {
- if (create_fake_symbol(e->patched, patched_sec, offset, entry_size))
- return -1;
-
- /* Symbolize alternative replacements: */
- if (!strcmp(patched_sec->name, ".altinstructions")) {
- struct reloc *reloc;
- unsigned char size;
-
- reloc = find_reloc_by_dest(e->patched, patched_sec, offset + ALT_NEW_OFFSET);
- if (!reloc) {
- ERROR_FUNC(patched_sec, offset + ALT_NEW_OFFSET, "can't find new reloc");
- return -1;
- }
-
- size = *(unsigned char *)(patched_sec->data->d_buf + offset + ALT_NEW_LEN_OFFSET);
-
- if (create_fake_symbol(e->patched, reloc->sym->sec,
- reloc->sym->offset + reloc_addend(reloc), size))
- return -1;
- }
- }
-
- /*
- * Extract all special section entries (and their dependencies) which
+ * Extract all special section symbols (and their dependencies) which
* reference included functions.
*/
sec_for_each_sym(patched_sec, patched_sym) {
@@ -1382,6 +1425,9 @@ static int clone_special_sections(struct elfs *e)
{
struct section *patched_sec;
+ if (create_fake_symbols(e->patched))
+ return -1;
+
for_each_sec(e->patched, patched_sec) {
if (is_special_section(patched_sec)) {
if (clone_special_section(e, patched_sec))
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 1dd9fc18fe624..5a979f52425ab 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -8,7 +8,6 @@
#include <objtool/objtool.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
int orc_dump(const char *filename)
{
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 9d380abc2ed35..1045e1380ffde 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -12,7 +12,6 @@
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
struct orc_list_entry {
struct list_head list;
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index fc2cf8dba1c03..e262af9171436 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -15,7 +15,6 @@
#include <objtool/builtin.h>
#include <objtool/special.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
struct special_entry {
const char *sec;
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index e1d98fb031575..e38167ca56a95 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -16,6 +16,7 @@ arch/x86/include/asm/orc_types.h
arch/x86/include/asm/emulate_prefix.h
arch/x86/lib/x86-opcode-map.txt
arch/x86/tools/gen-insn-attr-x86.awk
+include/linux/interval_tree_generic.h
include/linux/livepatch_external.h
include/linux/static_call_types.h
"On Wed, Sep 17, 2025 at 09:03:08AM -0700, Josh Poimboeuf wrote: > Changes since v3 (https://lore.kernel.org/cover.1750980516.git.jpoimboe@kernel.org): > > - Get rid of the SHF_MERGE+SHF_WRITE toolchain shenanigans in favor of > simple .discard.annotate_data annotations > - Fix potential double free in elf_create_reloc() > - Sync interval_tree_generic.h (Peter) > - Refactor prefix symbol creation error handling > - Rebase on tip/master and fix new issue (--checksum getting added with --noabs) > > (v3..v4 diff below) git branch: git://git.kernel.org/pub/scm/linux/kernel/git/jpoimboe/linux.git klp-build-v4 -- Josh
The s390 indirect thunks are placed in the .text.__s390_indirect_jump_*
sections.
Certain config options which enable -ffunction-sections have a custom
version of the TEXT_TEXT macro:
.text.[0-9a-zA-Z_]*
That unintentionally matches the thunk sections, causing them to get
grouped with normal text rather than being handled by their intended
rule later in the script:
*(.text.*_indirect_*)
Fix that by adding another period to the thunk section names, following
the kernel's general convention for distinguishing code-generated text
sections from compiler-generated ones.
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/s390/include/asm/nospec-insn.h | 2 +-
arch/s390/kernel/vmlinux.lds.S | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/s390/include/asm/nospec-insn.h b/arch/s390/include/asm/nospec-insn.h
index 6ce6b56e282b8..46f92bb4c9e50 100644
--- a/arch/s390/include/asm/nospec-insn.h
+++ b/arch/s390/include/asm/nospec-insn.h
@@ -19,7 +19,7 @@
#ifdef CONFIG_EXPOLINE_EXTERN
SYM_CODE_START(\name)
#else
- .pushsection .text.\name,"axG",@progbits,\name,comdat
+ .pushsection .text..\name,"axG",@progbits,\name,comdat
.globl \name
.hidden \name
.type \name,@function
diff --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index 1c606dfa595d8..79b514c72c5b4 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -51,7 +51,7 @@ SECTIONS
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
FTRACE_HOTPATCH_TRAMPOLINES_TEXT
- *(.text.*_indirect_*)
+ *(.text..*_indirect_*)
*(.gnu.warning)
. = ALIGN(PAGE_SIZE);
_etext = .; /* End of text section */
--
2.50.0TEXT_MAIN, DATA_MAIN and friends are defined differently depending on
whether certain config options enable -ffunction-sections and/or
-fdata-sections.
There's no technical reason for that beyond voodoo coding. Keeping the
separate implementations adds unnecessary complexity, fragments the
logic, and increases the risk of subtle bugs.
Unify the macros by using the same input section patterns across all
configs.
This is a prerequisite for the upcoming livepatch klp-build tooling
which will manually enable -ffunction-sections and -fdata-sections via
KCFLAGS.
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/asm-generic/vmlinux.lds.h | 40 ++++++++++---------------------
scripts/module.lds.S | 12 ++++------
2 files changed, 17 insertions(+), 35 deletions(-)
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ae2d2359b79e9..6b2311fa41393 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -87,39 +87,24 @@
#define ALIGN_FUNCTION() . = ALIGN(CONFIG_FUNCTION_ALIGNMENT)
/*
- * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections, which
- * generates .data.identifier sections, which need to be pulled in with
- * .data. We don't want to pull in .data..other sections, which Linux
- * has defined. Same for text and bss.
+ * Support -ffunction-sections by matching .text and .text.*,
+ * but exclude '.text..*'.
*
- * With LTO_CLANG, the linker also splits sections by default, so we need
- * these macros to combine the sections during the final link.
- *
- * With AUTOFDO_CLANG and PROPELLER_CLANG, by default, the linker splits
- * text sections and regroups functions into subsections.
- *
- * RODATA_MAIN is not used because existing code already defines .rodata.x
- * sections to be brought in with rodata.
+ * Special .text.* sections that are typically grouped separately, such as
+ * .text.unlikely or .text.hot, must be matched explicitly before using
+ * TEXT_MAIN.
*/
-#if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CLANG) || \
-defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
#define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
-#else
-#define TEXT_MAIN .text
-#endif
-#if defined(CONFIG_LD_DEAD_CODE_DATA_ELIMINATION) || defined(CONFIG_LTO_CLANG)
+
+/*
+ * Support -fdata-sections by matching .data, .data.*, and others,
+ * but exclude '.data..*'.
+ */
#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data.rel.* .data..L* .data..compoundliteral* .data.$__unnamed_* .data.$L*
#define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
#define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L*
#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..L* .bss..compoundliteral*
#define SBSS_MAIN .sbss .sbss.[0-9a-zA-Z_]*
-#else
-#define DATA_MAIN .data .data.rel .data.rel.local
-#define SDATA_MAIN .sdata
-#define RODATA_MAIN .rodata
-#define BSS_MAIN .bss
-#define SBSS_MAIN .sbss
-#endif
/*
* GCC 4.5 and later have a 32 bytes section alignment for structures.
@@ -580,9 +565,8 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
* during second ld run in second ld pass when generating System.map
*
* TEXT_MAIN here will match symbols with a fixed pattern (for example,
- * .text.hot or .text.unlikely) if dead code elimination or
- * function-section is enabled. Match these symbols first before
- * TEXT_MAIN to ensure they are grouped together.
+ * .text.hot or .text.unlikely). Match those before TEXT_MAIN to ensure
+ * they get grouped together.
*
* Also placing .text.hot section at the beginning of a page, this
* would help the TLB performance.
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index ee79c41059f3d..2632c6cb8ebe7 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -38,12 +38,10 @@ SECTIONS {
__kcfi_traps : { KEEP(*(.kcfi_traps)) }
#endif
-#ifdef CONFIG_LTO_CLANG
- /*
- * With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and
- * -ffunction-sections, which increases the size of the final module.
- * Merge the split sections in the final binary.
- */
+ .text : {
+ *(.text .text.[0-9a-zA-Z_]*)
+ }
+
.bss : {
*(.bss .bss.[0-9a-zA-Z_]*)
*(.bss..L*)
@@ -58,7 +56,7 @@ SECTIONS {
*(.rodata .rodata.[0-9a-zA-Z_]*)
*(.rodata..L*)
}
-#endif
+
MOD_SEPARATE_CODETAG_SECTIONS()
}
--
2.50.0Add the section number and reloc index to relocation error messages to
help find the faulty relocation.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/kernel/module.c | 15 +++++++++------
kernel/livepatch/core.c | 4 ++--
2 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index 0ffbae902e2fe..11c45ce42694c 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -97,6 +97,7 @@ static int __write_relocate_add(Elf64_Shdr *sechdrs,
DEBUGP("%s relocate section %u to %u\n",
apply ? "Applying" : "Clearing",
relsec, sechdrs[relsec].sh_info);
+
for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
size_t size;
@@ -162,15 +163,17 @@ static int __write_relocate_add(Elf64_Shdr *sechdrs,
if (apply) {
if (memcmp(loc, &zero, size)) {
- pr_err("x86/modules: Invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
- (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
+ pr_err("x86/modules: Invalid relocation target, existing value is nonzero for sec %u, idx %u, type %d, loc %lx, val %llx\n",
+ relsec, i, (int)ELF64_R_TYPE(rel[i].r_info),
+ (unsigned long)loc, val);
return -ENOEXEC;
}
write(loc, &val, size);
} else {
if (memcmp(loc, &val, size)) {
- pr_warn("x86/modules: Invalid relocation target, existing value does not match expected value for type %d, loc %p, val %Lx\n",
- (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
+ pr_warn("x86/modules: Invalid relocation target, existing value does not match expected value for sec %u, idx %u, type %d, loc %lx, val %llx\n",
+ relsec, i, (int)ELF64_R_TYPE(rel[i].r_info),
+ (unsigned long)loc, val);
return -ENOEXEC;
}
write(loc, &zero, size);
@@ -179,8 +182,8 @@ static int __write_relocate_add(Elf64_Shdr *sechdrs,
return 0;
overflow:
- pr_err("overflow in relocation type %d val %Lx\n",
- (int)ELF64_R_TYPE(rel[i].r_info), val);
+ pr_err("overflow in relocation type %d val %llx sec %u idx %d\n",
+ (int)ELF64_R_TYPE(rel[i].r_info), val, relsec, i);
pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
me->name);
return -ENOEXEC;
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 0e73fac55f8eb..7e443c2cf7d48 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -217,8 +217,8 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {
sym = (Elf_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
if (sym->st_shndx != SHN_LIVEPATCH) {
- pr_err("symbol %s is not marked as a livepatch symbol\n",
- strtab + sym->st_name);
+ pr_err("symbol %s at rela sec %u idx %d is not marked as a livepatch symbol\n",
+ strtab + sym->st_name, symndx, i);
return -EINVAL;
}
--
2.50.0Since commit 877b145f0f47 ("x86/kprobes: Move trampoline code into
RODATA"), the optprobe template code is no longer analyzed by objtool so
it doesn't need to be ignored.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/kernel/kprobes/opt.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 0aabd4c4e2c4f..6f826a00eca29 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -103,7 +103,6 @@ static void synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long val)
asm (
".pushsection .rodata\n"
- "optprobe_template_func:\n"
".global optprobe_template_entry\n"
"optprobe_template_entry:\n"
#ifdef CONFIG_X86_64
@@ -160,9 +159,6 @@ asm (
"optprobe_template_end:\n"
".popsection\n");
-void optprobe_template_func(void);
-STACK_FRAME_NON_STANDARD(optprobe_template_func);
-
#define TMPL_CLAC_IDX \
((long)optprobe_template_clac - (long)optprobe_template_entry)
#define TMPL_MOVE_IDX \
--
2.50.0In preparation for the objtool klp diff subcommand, add an underscore
between the name and the counter. This will make it possible for
objtool to distinguish between the non-unique and unique parts of the
symbol name so it can properly correlate the symbols.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/compiler.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 64ff73c533e54..db5796b8b0a71 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -163,7 +163,11 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
__asm__ ("" : "=r" (var) : "0" (var))
#endif
-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+/* Format: __UNIQUE_ID_<name>_<__COUNTER__> */
+#define __UNIQUE_ID(name) \
+ __PASTE(__UNIQUE_ID_, \
+ __PASTE(name, \
+ __PASTE(_, __COUNTER__)))
/**
* data_race - mark an expression as containing intentional data races
--
2.50.0Avoid underscore overload by changing:
__UNIQUE_ID___addressable_loops_per_jiffy_868
to the following:
__UNIQUE_ID_addressable_loops_per_jiffy_868
This matches the format used by other __UNIQUE_ID()-generated symbols
and improves readability for those who stare at ELF symbol table dumps.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/compiler.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index db5796b8b0a71..9bc690be60675 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -287,7 +287,7 @@ static inline void *offset_to_ptr(const int *off)
*/
#define ___ADDRESSABLE(sym, __attrs) \
static void * __used __attrs \
- __UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)(uintptr_t)&sym;
+ __UNIQUE_ID(__PASTE(addressable_, sym)) = (void *)(uintptr_t)&sym;
#define __ADDRESSABLE(sym) \
___ADDRESSABLE(sym, __section(".discard.addressable"))
--
2.50.0In preparation for the objtool klp diff subcommand, replace the custom
unique symbol name generation in ELFNOTE() with __UNIQUE_ID().
This standardizes the naming format for all "unique" symbols, which will
allow objtool to properly correlate them. Note this also removes the
"one ELF note per line" limitation.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/elfnote.h | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/include/linux/elfnote.h b/include/linux/elfnote.h
index 69b136e4dd2b6..bb3dcded055fc 100644
--- a/include/linux/elfnote.h
+++ b/include/linux/elfnote.h
@@ -60,23 +60,21 @@
#else /* !__ASSEMBLER__ */
#include <uapi/linux/elf.h>
+#include <linux/compiler.h>
/*
* Use an anonymous structure which matches the shape of
* Elf{32,64}_Nhdr, but includes the name and desc data. The size and
* type of name and desc depend on the macro arguments. "name" must
- * be a literal string, and "desc" must be passed by value. You may
- * only define one note per line, since __LINE__ is used to generate
- * unique symbols.
+ * be a literal string, and "desc" must be passed by value.
*/
-#define _ELFNOTE_PASTE(a,b) a##b
-#define _ELFNOTE(size, name, unique, type, desc) \
+#define ELFNOTE(size, name, type, desc) \
static const struct { \
struct elf##size##_note _nhdr; \
unsigned char _name[sizeof(name)] \
__attribute__((aligned(sizeof(Elf##size##_Word)))); \
typeof(desc) _desc \
__attribute__((aligned(sizeof(Elf##size##_Word)))); \
- } _ELFNOTE_PASTE(_note_, unique) \
+ } __UNIQUE_ID(note) \
__used \
__attribute__((section(".note." name), \
aligned(sizeof(Elf##size##_Word)), \
@@ -89,11 +87,10 @@
name, \
desc \
}
-#define ELFNOTE(size, name, type, desc) \
- _ELFNOTE(size, name, __LINE__, type, desc)
#define ELFNOTE32(name, type, desc) ELFNOTE(32, name, type, desc)
#define ELFNOTE64(name, type, desc) ELFNOTE(64, name, type, desc)
+
#endif /* __ASSEMBLER__ */
#endif /* _LINUX_ELFNOTE_H */
--
2.50.0In preparation for the objtool klp diff subcommand, remove the arbitrary
'kmod_' prefix from __KBUILD_MODNAME and instead add it explicitly in
the __initcall_id() macro.
This change supports the standardization of "unique" symbol naming by
ensuring the non-unique portion of the name comes before the unique
part. That will enable objtool to properly correlate symbols across
builds.
Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/init.h | 3 ++-
scripts/Makefile.lib | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/linux/init.h b/include/linux/init.h
index 17c1bc712e234..40331923b9f4a 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -200,12 +200,13 @@ extern struct module __this_module;
/* Format: <modname>__<counter>_<line>_<fn> */
#define __initcall_id(fn) \
+ __PASTE(kmod_, \
__PASTE(__KBUILD_MODNAME, \
__PASTE(__, \
__PASTE(__COUNTER__, \
__PASTE(_, \
__PASTE(__LINE__, \
- __PASTE(_, fn))))))
+ __PASTE(_, fn)))))))
/* Format: __<prefix>__<iid><id> */
#define __initcall_name(prefix, __iid, id) \
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 1d581ba5df66f..b955602661240 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -20,7 +20,7 @@ name-fix-token = $(subst $(comma),_,$(subst -,_,$1))
name-fix = $(call stringify,$(call name-fix-token,$1))
basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))
modname_flags = -DKBUILD_MODNAME=$(call name-fix,$(modname)) \
- -D__KBUILD_MODNAME=kmod_$(call name-fix-token,$(modname))
+ -D__KBUILD_MODNAME=$(call name-fix-token,$(modname))
modfile_flags = -DKBUILD_MODFILE=$(call stringify,$(modfile))
_c_flags = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
--
2.50.0In preparation for klp-build livepatch module creation tooling,
suppress warnings for unresolved references to linker-generated
__start_* and __stop_* section bounds symbols.
These symbols are expected to be undefined when modpost runs, as they're
created later by the linker.
Cc: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/mod/modpost.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 5ca7c268294eb..c2b2c8fa6d258 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -606,6 +606,11 @@ static int ignore_undef_symbol(struct elf_info *info, const char *symname)
strstarts(symname, "_savevr_") ||
strcmp(symname, ".TOC.") == 0)
return 1;
+
+ /* ignore linker-created section bounds variables */
+ if (strstarts(symname, "__start_") || strstarts(symname, "__stop_"))
+ return 1;
+
/* Do not ignore this symbol */
return 0;
}
--
2.50.0The INT3 call emulation selftest is a bit fragile as it relies on the
compiler not inserting any extra instructions before the
int3_selftest_ip() definition.
Also, the int3_selftest_ip() symbol overlaps with the int3_selftest
symbol(), which can confuse objtool.
Fix those issues by slightly reworking the functionality and moving
int3_selftest_ip() to a separate asm function. While at it, improve the
naming.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/kernel/alternative.c | 51 +++++++++++++++++++----------------
1 file changed, 28 insertions(+), 23 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 69fb818df2eed..9e7f03172a227 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -2244,21 +2244,34 @@ int alternatives_text_reserved(void *start, void *end)
* See entry_{32,64}.S for more details.
*/
-/*
- * We define the int3_magic() function in assembly to control the calling
- * convention such that we can 'call' it from assembly.
- */
-
-extern void int3_magic(unsigned int *ptr); /* defined in asm */
+extern void int3_selftest_asm(unsigned int *ptr);
asm (
" .pushsection .init.text, \"ax\", @progbits\n"
-" .type int3_magic, @function\n"
-"int3_magic:\n"
+" .type int3_selftest_asm, @function\n"
+"int3_selftest_asm:\n"
ANNOTATE_NOENDBR
-" movl $1, (%" _ASM_ARG1 ")\n"
+ /*
+ * INT3 padded with NOP to CALL_INSN_SIZE. The INT3 triggers an
+ * exception, then the int3_exception_nb notifier emulates a call to
+ * int3_selftest_callee().
+ */
+" int3; nop; nop; nop; nop\n"
ASM_RET
-" .size int3_magic, .-int3_magic\n"
+" .size int3_selftest_asm, . - int3_selftest_asm\n"
+" .popsection\n"
+);
+
+extern void int3_selftest_callee(unsigned int *ptr);
+
+asm (
+" .pushsection .init.text, \"ax\", @progbits\n"
+" .type int3_selftest_callee, @function\n"
+"int3_selftest_callee:\n"
+ ANNOTATE_NOENDBR
+" movl $0x1234, (%" _ASM_ARG1 ")\n"
+ ASM_RET
+" .size int3_selftest_callee, . - int3_selftest_callee\n"
" .popsection\n"
);
@@ -2267,7 +2280,7 @@ extern void int3_selftest_ip(void); /* defined in asm below */
static int __init
int3_exception_notify(struct notifier_block *self, unsigned long val, void *data)
{
- unsigned long selftest = (unsigned long)&int3_selftest_ip;
+ unsigned long selftest = (unsigned long)&int3_selftest_asm;
struct die_args *args = data;
struct pt_regs *regs = args->regs;
@@ -2282,7 +2295,7 @@ int3_exception_notify(struct notifier_block *self, unsigned long val, void *data
if (regs->ip - INT3_INSN_SIZE != selftest)
return NOTIFY_DONE;
- int3_emulate_call(regs, (unsigned long)&int3_magic);
+ int3_emulate_call(regs, (unsigned long)&int3_selftest_callee);
return NOTIFY_STOP;
}
@@ -2298,19 +2311,11 @@ static noinline void __init int3_selftest(void)
BUG_ON(register_die_notifier(&int3_exception_nb));
/*
- * Basically: int3_magic(&val); but really complicated :-)
- *
- * INT3 padded with NOP to CALL_INSN_SIZE. The int3_exception_nb
- * notifier above will emulate CALL for us.
+ * Basically: int3_selftest_callee(&val); but really complicated :-)
*/
- asm volatile ("int3_selftest_ip:\n\t"
- ANNOTATE_NOENDBR
- " int3; nop; nop; nop; nop\n\t"
- : ASM_CALL_CONSTRAINT
- : __ASM_SEL_RAW(a, D) (&val)
- : "memory");
+ int3_selftest_asm(&val);
- BUG_ON(val != 1);
+ BUG_ON(val != 0x1234);
unregister_die_notifier(&int3_exception_nb);
}
--
2.50.0The following commit made an improvement to interval_tree_generic.h, but
didn't sync it to the tools copy:
19811285784f ("lib/interval_tree: skip the check before go to the right subtree")
Sync it, and add it to objtool's sync-check.sh so they are more likely
to stay in sync going forward.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/include/linux/interval_tree_generic.h | 8 ++------
tools/objtool/sync-check.sh | 1 +
2 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/tools/include/linux/interval_tree_generic.h b/tools/include/linux/interval_tree_generic.h
index aaa8a0767aa3a..1b400f26f63d6 100644
--- a/tools/include/linux/interval_tree_generic.h
+++ b/tools/include/linux/interval_tree_generic.h
@@ -104,12 +104,8 @@ ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
if (ITSTART(node) <= last) { /* Cond1 */ \
if (start <= ITLAST(node)) /* Cond2 */ \
return node; /* node is leftmost match */ \
- if (node->ITRB.rb_right) { \
- node = rb_entry(node->ITRB.rb_right, \
- ITSTRUCT, ITRB); \
- if (start <= node->ITSUBTREE) \
- continue; \
- } \
+ node = rb_entry(node->ITRB.rb_right, ITSTRUCT, ITRB); \
+ continue; \
} \
return NULL; /* No match */ \
} \
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index 81d120d054425..86d64e3ac6f73 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -16,6 +16,7 @@ arch/x86/include/asm/orc_types.h
arch/x86/include/asm/emulate_prefix.h
arch/x86/lib/x86-opcode-map.txt
arch/x86/tools/gen-insn-attr-x86.awk
+include/linux/interval_tree_generic.h
include/linux/static_call_types.h
"
--
2.50.0For consistency with the other function templates, change
_subtree_search_*() to use the user-supplied ITSTATIC rather than the
hard-coded 'static'.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/interval_tree.h | 4 ++++
include/linux/interval_tree_generic.h | 2 +-
include/linux/mm.h | 2 ++
tools/include/linux/interval_tree_generic.h | 2 +-
4 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/include/linux/interval_tree.h b/include/linux/interval_tree.h
index 2b8026a399064..9d5791e9f737a 100644
--- a/include/linux/interval_tree.h
+++ b/include/linux/interval_tree.h
@@ -19,6 +19,10 @@ extern void
interval_tree_remove(struct interval_tree_node *node,
struct rb_root_cached *root);
+extern struct interval_tree_node *
+interval_tree_subtree_search(struct interval_tree_node *node,
+ unsigned long start, unsigned long last);
+
extern struct interval_tree_node *
interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
diff --git a/include/linux/interval_tree_generic.h b/include/linux/interval_tree_generic.h
index 1b400f26f63d6..c5a2fed49eb0d 100644
--- a/include/linux/interval_tree_generic.h
+++ b/include/linux/interval_tree_generic.h
@@ -77,7 +77,7 @@ ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, \
* Cond2: start <= ITLAST(node) \
*/ \
\
-static ITSTRUCT * \
+ITSTATIC ITSTRUCT * \
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
while (true) { \
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1ae97a0b8ec75..69baa9a1e2cb4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3265,6 +3265,8 @@ void vma_interval_tree_insert_after(struct vm_area_struct *node,
struct rb_root_cached *root);
void vma_interval_tree_remove(struct vm_area_struct *node,
struct rb_root_cached *root);
+struct vm_area_struct *vma_interval_tree_subtree_search(struct vm_area_struct *node,
+ unsigned long start, unsigned long last);
struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
diff --git a/tools/include/linux/interval_tree_generic.h b/tools/include/linux/interval_tree_generic.h
index 1b400f26f63d6..c5a2fed49eb0d 100644
--- a/tools/include/linux/interval_tree_generic.h
+++ b/tools/include/linux/interval_tree_generic.h
@@ -77,7 +77,7 @@ ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, \
* Cond2: start <= ITLAST(node) \
*/ \
\
-static ITSTRUCT * \
+ITSTATIC ITSTRUCT * \
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
while (true) { \
--
2.50.0For consistency with the other function templates, change
_subtree_search_*() to use the user-supplied ITSTATIC rather than the
hard-coded 'static'.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
v4.1: Fixed a couple more INTERVAL_TREE_DEFINE usages.
drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.h | 4 ++++
include/linux/interval_tree.h | 4 ++++
include/linux/interval_tree_generic.h | 2 +-
include/linux/mm.h | 2 ++
lib/interval_tree.c | 1 +
tools/include/linux/interval_tree_generic.h | 2 +-
6 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.h b/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.h
index 1d7fc3226bcad..cfb42a8f5768b 100644
--- a/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.h
+++ b/drivers/infiniband/hw/usnic/usnic_uiom_interval_tree.h
@@ -53,6 +53,10 @@ extern void
usnic_uiom_interval_tree_remove(struct usnic_uiom_interval_node *node,
struct rb_root_cached *root);
extern struct usnic_uiom_interval_node *
+usnic_uiom_interval_tree_subtree_search(struct usnic_uiom_interval_node *node,
+ unsigned long start,
+ unsigned long last);
+extern struct usnic_uiom_interval_node *
usnic_uiom_interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start,
unsigned long last);
diff --git a/include/linux/interval_tree.h b/include/linux/interval_tree.h
index 2b8026a399064..9d5791e9f737a 100644
--- a/include/linux/interval_tree.h
+++ b/include/linux/interval_tree.h
@@ -19,6 +19,10 @@ extern void
interval_tree_remove(struct interval_tree_node *node,
struct rb_root_cached *root);
+extern struct interval_tree_node *
+interval_tree_subtree_search(struct interval_tree_node *node,
+ unsigned long start, unsigned long last);
+
extern struct interval_tree_node *
interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
diff --git a/include/linux/interval_tree_generic.h b/include/linux/interval_tree_generic.h
index 1b400f26f63d6..c5a2fed49eb0d 100644
--- a/include/linux/interval_tree_generic.h
+++ b/include/linux/interval_tree_generic.h
@@ -77,7 +77,7 @@ ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, \
* Cond2: start <= ITLAST(node) \
*/ \
\
-static ITSTRUCT * \
+ITSTATIC ITSTRUCT * \
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
while (true) { \
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1ae97a0b8ec75..69baa9a1e2cb4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3265,6 +3265,8 @@ void vma_interval_tree_insert_after(struct vm_area_struct *node,
struct rb_root_cached *root);
void vma_interval_tree_remove(struct vm_area_struct *node,
struct rb_root_cached *root);
+struct vm_area_struct *vma_interval_tree_subtree_search(struct vm_area_struct *node,
+ unsigned long start, unsigned long last);
struct vm_area_struct *vma_interval_tree_iter_first(struct rb_root_cached *root,
unsigned long start, unsigned long last);
struct vm_area_struct *vma_interval_tree_iter_next(struct vm_area_struct *node,
diff --git a/lib/interval_tree.c b/lib/interval_tree.c
index 324766e9bf637..9ceb084b6b4ef 100644
--- a/lib/interval_tree.c
+++ b/lib/interval_tree.c
@@ -13,6 +13,7 @@ INTERVAL_TREE_DEFINE(struct interval_tree_node, rb,
EXPORT_SYMBOL_GPL(interval_tree_insert);
EXPORT_SYMBOL_GPL(interval_tree_remove);
+EXPORT_SYMBOL_GPL(interval_tree_subtree_search);
EXPORT_SYMBOL_GPL(interval_tree_iter_first);
EXPORT_SYMBOL_GPL(interval_tree_iter_next);
diff --git a/tools/include/linux/interval_tree_generic.h b/tools/include/linux/interval_tree_generic.h
index 1b400f26f63d6..c5a2fed49eb0d 100644
--- a/tools/include/linux/interval_tree_generic.h
+++ b/tools/include/linux/interval_tree_generic.h
@@ -77,7 +77,7 @@ ITSTATIC void ITPREFIX ## _remove(ITSTRUCT *node, \
* Cond2: start <= ITLAST(node) \
*/ \
\
-static ITSTRUCT * \
+ITSTATIC ITSTRUCT * \
ITPREFIX ## _subtree_search(ITSTRUCT *node, ITTYPE start, ITTYPE last) \
{ \
while (true) { \
--
2.50.0In the rare case of overlapping symbols, find_symbol_containing() just
returns the first one it finds. Make it slightly less arbitrary by
returning the smallest symbol with size > 0.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index ca5d77db692a2..1c1bb2cb960da 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -193,14 +193,29 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset)
struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset)
{
struct rb_root_cached *tree = (struct rb_root_cached *)&sec->symbol_tree;
- struct symbol *iter;
+ struct symbol *sym = NULL, *tmp;
- __sym_for_each(iter, tree, offset, offset) {
- if (iter->type != STT_SECTION)
- return iter;
+ __sym_for_each(tmp, tree, offset, offset) {
+ if (tmp->len) {
+ if (!sym) {
+ sym = tmp;
+ continue;
+ }
+
+ if (sym->offset != tmp->offset || sym->len != tmp->len) {
+ /*
+ * In the rare case of overlapping symbols,
+ * pick the smaller one.
+ *
+ * TODO: outlaw overlapping symbols
+ */
+ if (tmp->len < sym->len)
+ sym = tmp;
+ }
+ }
}
- return NULL;
+ return sym;
}
/*
--
2.50.0The free(sym) call in the read_symbols() error path is fundamentally
broken: 'sym' doesn't point to any allocated block. If triggered,
things would go from bad to worse.
Remove the free() and simplify the error paths. Freeing memory isn't
necessary here anyway, these are fatal errors which lead to an immediate
exit().
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 1c1bb2cb960da..b009d9feed760 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -492,14 +492,14 @@ static int read_symbols(struct elf *elf)
if (!gelf_getsymshndx(symtab->data, shndx_data, i, &sym->sym,
&shndx)) {
ERROR_ELF("gelf_getsymshndx");
- goto err;
+ return -1;
}
sym->name = elf_strptr(elf->elf, symtab->sh.sh_link,
sym->sym.st_name);
if (!sym->name) {
ERROR_ELF("elf_strptr");
- goto err;
+ return -1;
}
if ((sym->sym.st_shndx > SHN_UNDEF &&
@@ -511,7 +511,7 @@ static int read_symbols(struct elf *elf)
sym->sec = find_section_by_index(elf, shndx);
if (!sym->sec) {
ERROR("couldn't find section for symbol %s", sym->name);
- goto err;
+ return -1;
}
if (GELF_ST_TYPE(sym->sym.st_info) == STT_SECTION) {
sym->name = sym->sec->name;
@@ -581,10 +581,6 @@ static int read_symbols(struct elf *elf)
}
return 0;
-
-err:
- free(sym);
- return -1;
}
static int mark_group_syms(struct elf *elf)
--
2.50.0Properly check and propagate the return value of elf_truncate_section()
to avoid silent failures.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index b009d9feed760..19e249f4783cf 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1307,7 +1307,6 @@ static int elf_truncate_section(struct elf *elf, struct section *sec)
for (;;) {
/* get next data descriptor for the relevant section */
data = elf_getdata(s, data);
-
if (!data) {
if (size) {
ERROR("end of section data but non-zero size left\n");
@@ -1343,8 +1342,8 @@ int elf_write(struct elf *elf)
/* Update changed relocation sections and section headers: */
list_for_each_entry(sec, &elf->sections, list) {
- if (sec->truncate)
- elf_truncate_section(elf, sec);
+ if (sec->truncate && elf_truncate_section(elf, sec))
+ return -1;
if (sec_changed(sec)) {
s = elf_getscn(elf->elf, sec->idx);
--
2.50.0Up to a certain point in objtool's execution, all errors are fatal and
return -1. When propagating such errors, just return -1 directly
instead of trying to propagate the original return code. This helps
make the code more compact and the behavior more explicit.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 151 +++++++++++++++-------------------------
tools/objtool/special.c | 9 +--
2 files changed, 59 insertions(+), 101 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 6d6323508e4b8..dbdbbddd01ecb 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -430,7 +430,6 @@ static int decode_instructions(struct objtool_file *file)
struct symbol *func;
unsigned long offset;
struct instruction *insn;
- int ret;
for_each_sec(file, sec) {
struct instruction *insns = NULL;
@@ -479,11 +478,8 @@ static int decode_instructions(struct objtool_file *file)
insn->offset = offset;
insn->prev_len = prev_len;
- ret = arch_decode_instruction(file, sec, offset,
- sec->sh.sh_size - offset,
- insn);
- if (ret)
- return ret;
+ if (arch_decode_instruction(file, sec, offset, sec->sh.sh_size - offset, insn))
+ return -1;
prev_len = insn->len;
@@ -599,7 +595,7 @@ static int init_pv_ops(struct objtool_file *file)
};
const char *pv_ops;
struct symbol *sym;
- int idx, nr, ret;
+ int idx, nr;
if (!opts.noinstr)
return 0;
@@ -621,9 +617,8 @@ static int init_pv_ops(struct objtool_file *file)
INIT_LIST_HEAD(&file->pv_ops[idx].targets);
for (idx = 0; (pv_ops = pv_ops_tables[idx]); idx++) {
- ret = add_pv_ops(file, pv_ops);
- if (ret)
- return ret;
+ if (add_pv_ops(file, pv_ops))
+ return -1;
}
return 0;
@@ -1484,7 +1479,6 @@ static int add_jump_destinations(struct objtool_file *file)
struct reloc *reloc;
struct section *dest_sec;
unsigned long dest_off;
- int ret;
for_each_insn(file, insn) {
struct symbol *func = insn_func(insn);
@@ -1507,9 +1501,8 @@ static int add_jump_destinations(struct objtool_file *file)
dest_sec = reloc->sym->sec;
dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
} else if (reloc->sym->retpoline_thunk) {
- ret = add_retpoline_call(file, insn);
- if (ret)
- return ret;
+ if (add_retpoline_call(file, insn))
+ return -1;
continue;
} else if (reloc->sym->return_thunk) {
add_return_call(file, insn, true);
@@ -1519,9 +1512,8 @@ static int add_jump_destinations(struct objtool_file *file)
* External sibling call or internal sibling call with
* STT_FUNC reloc.
*/
- ret = add_call_dest(file, insn, reloc->sym, true);
- if (ret)
- return ret;
+ if (add_call_dest(file, insn, reloc->sym, true))
+ return -1;
continue;
} else if (reloc->sym->sec->idx) {
dest_sec = reloc->sym->sec;
@@ -1570,9 +1562,8 @@ static int add_jump_destinations(struct objtool_file *file)
*/
if (jump_dest->sym && jump_dest->offset == jump_dest->sym->offset) {
if (jump_dest->sym->retpoline_thunk) {
- ret = add_retpoline_call(file, insn);
- if (ret)
- return ret;
+ if (add_retpoline_call(file, insn))
+ return -1;
continue;
}
if (jump_dest->sym->return_thunk) {
@@ -1613,9 +1604,8 @@ static int add_jump_destinations(struct objtool_file *file)
* Internal sibling call without reloc or with
* STT_SECTION reloc.
*/
- ret = add_call_dest(file, insn, insn_func(jump_dest), true);
- if (ret)
- return ret;
+ if (add_call_dest(file, insn, insn_func(jump_dest), true))
+ return -1;
continue;
}
@@ -1645,7 +1635,6 @@ static int add_call_destinations(struct objtool_file *file)
unsigned long dest_off;
struct symbol *dest;
struct reloc *reloc;
- int ret;
for_each_insn(file, insn) {
struct symbol *func = insn_func(insn);
@@ -1657,9 +1646,8 @@ static int add_call_destinations(struct objtool_file *file)
dest_off = arch_jump_destination(insn);
dest = find_call_destination(insn->sec, dest_off);
- ret = add_call_dest(file, insn, dest, false);
- if (ret)
- return ret;
+ if (add_call_dest(file, insn, dest, false))
+ return -1;
if (func && func->ignore)
continue;
@@ -1683,19 +1671,16 @@ static int add_call_destinations(struct objtool_file *file)
return -1;
}
- ret = add_call_dest(file, insn, dest, false);
- if (ret)
- return ret;
+ if (add_call_dest(file, insn, dest, false))
+ return -1;
} else if (reloc->sym->retpoline_thunk) {
- ret = add_retpoline_call(file, insn);
- if (ret)
- return ret;
+ if (add_retpoline_call(file, insn))
+ return -1;
} else {
- ret = add_call_dest(file, insn, reloc->sym, false);
- if (ret)
- return ret;
+ if (add_call_dest(file, insn, reloc->sym, false))
+ return -1;
}
}
@@ -1912,7 +1897,6 @@ static int add_special_section_alts(struct objtool_file *file)
struct instruction *orig_insn, *new_insn;
struct special_alt *special_alt, *tmp;
struct alternative *alt;
- int ret;
if (special_get_alts(file->elf, &special_alts))
return -1;
@@ -1944,16 +1928,12 @@ static int add_special_section_alts(struct objtool_file *file)
continue;
}
- ret = handle_group_alt(file, special_alt, orig_insn,
- &new_insn);
- if (ret)
- return ret;
+ if (handle_group_alt(file, special_alt, orig_insn, &new_insn))
+ return -1;
} else if (special_alt->jump_or_nop) {
- ret = handle_jump_alt(file, special_alt, orig_insn,
- &new_insn);
- if (ret)
- return ret;
+ if (handle_jump_alt(file, special_alt, orig_insn, &new_insn))
+ return -1;
}
alt = calloc(1, sizeof(*alt));
@@ -2141,15 +2121,13 @@ static int add_func_jump_tables(struct objtool_file *file,
struct symbol *func)
{
struct instruction *insn;
- int ret;
func_for_each_insn(file, func, insn) {
if (!insn_jump_table(insn))
continue;
- ret = add_jump_table(file, insn);
- if (ret)
- return ret;
+ if (add_jump_table(file, insn))
+ return -1;
}
return 0;
@@ -2163,7 +2141,6 @@ static int add_func_jump_tables(struct objtool_file *file,
static int add_jump_table_alts(struct objtool_file *file)
{
struct symbol *func;
- int ret;
if (!file->rodata)
return 0;
@@ -2173,9 +2150,8 @@ static int add_jump_table_alts(struct objtool_file *file)
continue;
mark_func_jump_tables(file, func);
- ret = add_func_jump_tables(file, func);
- if (ret)
- return ret;
+ if (add_func_jump_tables(file, func))
+ return -1;
}
return 0;
@@ -2299,7 +2275,7 @@ static int read_annotate(struct objtool_file *file,
struct instruction *insn;
struct reloc *reloc;
uint64_t offset;
- int type, ret;
+ int type;
sec = find_section_by_name(file->elf, ".discard.annotate_insn");
if (!sec)
@@ -2329,9 +2305,8 @@ static int read_annotate(struct objtool_file *file,
return -1;
}
- ret = func(file, type, insn);
- if (ret < 0)
- return ret;
+ if (func(file, type, insn))
+ return -1;
}
return 0;
@@ -2540,76 +2515,62 @@ static void mark_rodata(struct objtool_file *file)
static int decode_sections(struct objtool_file *file)
{
- int ret;
-
mark_rodata(file);
- ret = init_pv_ops(file);
- if (ret)
- return ret;
+ if (init_pv_ops(file))
+ return -1;
/*
* Must be before add_{jump_call}_destination.
*/
- ret = classify_symbols(file);
- if (ret)
- return ret;
+ if (classify_symbols(file))
+ return -1;
- ret = decode_instructions(file);
- if (ret)
- return ret;
+ if (decode_instructions(file))
+ return -1;
- ret = add_ignores(file);
- if (ret)
- return ret;
+ if (add_ignores(file))
+ return -1;
add_uaccess_safe(file);
- ret = read_annotate(file, __annotate_early);
- if (ret)
- return ret;
+ if (read_annotate(file, __annotate_early))
+ return -1;
/*
* Must be before add_jump_destinations(), which depends on 'func'
* being set for alternatives, to enable proper sibling call detection.
*/
if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) {
- ret = add_special_section_alts(file);
- if (ret)
- return ret;
+ if (add_special_section_alts(file))
+ return -1;
}
- ret = add_jump_destinations(file);
- if (ret)
- return ret;
+ if (add_jump_destinations(file))
+ return -1;
/*
* Must be before add_call_destination(); it changes INSN_CALL to
* INSN_JUMP.
*/
- ret = read_annotate(file, __annotate_ifc);
- if (ret)
- return ret;
+ if (read_annotate(file, __annotate_ifc))
+ return -1;
- ret = add_call_destinations(file);
- if (ret)
- return ret;
+ if (add_call_destinations(file))
+ return -1;
- ret = add_jump_table_alts(file);
- if (ret)
- return ret;
+ if (add_jump_table_alts(file))
+ return -1;
- ret = read_unwind_hints(file);
- if (ret)
- return ret;
+ if (read_unwind_hints(file))
+ return -1;
/*
* Must be after add_call_destinations() such that it can override
* dead_end_function() marks.
*/
- ret = read_annotate(file, __annotate_late);
- if (ret)
- return ret;
+ if (read_annotate(file, __annotate_late))
+ return -1;
return 0;
}
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index c80fed8a840ee..c0beefb93b62e 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -133,7 +133,7 @@ int special_get_alts(struct elf *elf, struct list_head *alts)
struct section *sec;
unsigned int nr_entries;
struct special_alt *alt;
- int idx, ret;
+ int idx;
INIT_LIST_HEAD(alts);
@@ -157,11 +157,8 @@ int special_get_alts(struct elf *elf, struct list_head *alts)
}
memset(alt, 0, sizeof(*alt));
- ret = get_alt_entry(elf, entry, sec, idx, alt);
- if (ret > 0)
- continue;
- if (ret < 0)
- return ret;
+ if (get_alt_entry(elf, entry, sec, idx, alt))
+ return -1;
list_add_tail(&alt->list, alts);
}
--
2.50.0The following commit
5da6aea375cd ("objtool: Fix find_{symbol,func}_containing()")
fixed the issue where overlapping symbols weren't getting sorted
properly in the symbol tree. Therefore the workaround to skip adding
empty symbols from the following commit
a2e38dffcd93 ("objtool: Don't add empty symbols to the rbtree")
is no longer needed.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 19e249f4783cf..a8a78b55d3ece 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -96,7 +96,8 @@ static inline unsigned long __sym_last(struct symbol *s)
}
INTERVAL_TREE_DEFINE(struct symbol, node, unsigned long, __subtree_last,
- __sym_start, __sym_last, static, __sym)
+ __sym_start, __sym_last, static inline __maybe_unused,
+ __sym)
#define __sym_for_each(_iter, _tree, _start, _end) \
for (_iter = __sym_iter_first((_tree), (_start), (_end)); \
@@ -440,13 +441,6 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
list_add(&sym->list, entry);
elf_hash_add(symbol, &sym->hash, sym->idx);
elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
-
- /*
- * Don't store empty STT_NOTYPE symbols in the rbtree. They
- * can exist within a function, confusing the sorting.
- */
- if (!sym->len)
- __sym_remove(sym, &sym->sec->symbol_tree);
}
static int read_symbols(struct elf *elf)
--
2.50.0Zero-length symbols get inserted in the wrong spot. Fix that.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index a8a78b55d3ece..c024937eb12a2 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -92,7 +92,7 @@ static inline unsigned long __sym_start(struct symbol *s)
static inline unsigned long __sym_last(struct symbol *s)
{
- return s->offset + s->len - 1;
+ return s->offset + (s->len ? s->len - 1 : 0);
}
INTERVAL_TREE_DEFINE(struct symbol, node, unsigned long, __subtree_last,
--
2.50.0find_symbol_hole_containing() fails to find a symbol hole (aka stripped
weak symbol) if its section has no symbols before the hole. This breaks
weak symbol detection if -ffunction-sections is enabled.
Fix that by allowing the interval tree to contain section symbols, which
are always at offset zero for a given section.
Fixes a bunch of (-ffunction-sections) warnings like:
vmlinux.o: warning: objtool: .text.__x64_sys_io_setup+0x10: unreachable instruction
Fixes: 4adb23686795 ("objtool: Ignore extra-symbol code")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c024937eb12a2..d7fb3d0b05cf1 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -109,7 +109,7 @@ struct symbol_hole {
};
/*
- * Find !section symbol where @offset is after it.
+ * Find the last symbol before @offset.
*/
static int symbol_hole_by_offset(const void *key, const struct rb_node *node)
{
@@ -120,8 +120,7 @@ static int symbol_hole_by_offset(const void *key, const struct rb_node *node)
return -1;
if (sh->key >= s->offset + s->len) {
- if (s->type != STT_SECTION)
- sh->sym = s;
+ sh->sym = s;
return 1;
}
@@ -428,7 +427,8 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
sym->len = sym->sym.st_size;
__sym_for_each(iter, &sym->sec->symbol_tree, sym->offset, sym->offset) {
- if (iter->offset == sym->offset && iter->type == sym->type)
+ if (iter->offset == sym->offset && iter->type == sym->type &&
+ iter->len == sym->len)
iter->alias = sym;
}
--
2.50.0On x86, arch_dest_reloc_offset() hardcodes the addend adjustment to
four, but the actual adjustment depends on the relocation type. Fix
that.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/arch/loongarch/decode.c | 4 ++--
tools/objtool/arch/powerpc/decode.c | 4 ++--
tools/objtool/arch/x86/decode.c | 9 +++++++--
tools/objtool/check.c | 15 +++++----------
tools/objtool/include/objtool/arch.h | 2 +-
5 files changed, 17 insertions(+), 17 deletions(-)
diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
index b6fdc68053cc4..330671d88c590 100644
--- a/tools/objtool/arch/loongarch/decode.c
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -17,9 +17,9 @@ unsigned long arch_jump_destination(struct instruction *insn)
return insn->offset + (insn->immediate << 2);
}
-unsigned long arch_dest_reloc_offset(int addend)
+s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
{
- return addend;
+ return reloc_addend(reloc);
}
bool arch_pc_relative_reloc(struct reloc *reloc)
diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
index c851c51d4bd35..9b17885e6cba6 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -14,9 +14,9 @@ int arch_ftrace_match(char *name)
return !strcmp(name, "_mcount");
}
-unsigned long arch_dest_reloc_offset(int addend)
+s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
{
- return addend;
+ return reloc_addend(reloc);
}
bool arch_callee_saved_reg(unsigned char reg)
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 0ad5cc70ecbe7..6742002a01f55 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -68,9 +68,14 @@ bool arch_callee_saved_reg(unsigned char reg)
}
}
-unsigned long arch_dest_reloc_offset(int addend)
+s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
{
- return addend + 4;
+ s64 addend = reloc_addend(reloc);
+
+ if (arch_pc_relative_reloc(reloc))
+ addend += insn->offset + insn->len - reloc_offset(reloc);
+
+ return addend;
}
unsigned long arch_jump_destination(struct instruction *insn)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index dbdbbddd01ecb..1165dd1669f0b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1499,7 +1499,7 @@ static int add_jump_destinations(struct objtool_file *file)
dest_off = arch_jump_destination(insn);
} else if (reloc->sym->type == STT_SECTION) {
dest_sec = reloc->sym->sec;
- dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
+ dest_off = arch_insn_adjusted_addend(insn, reloc);
} else if (reloc->sym->retpoline_thunk) {
if (add_retpoline_call(file, insn))
return -1;
@@ -1518,7 +1518,7 @@ static int add_jump_destinations(struct objtool_file *file)
} else if (reloc->sym->sec->idx) {
dest_sec = reloc->sym->sec;
dest_off = reloc->sym->sym.st_value +
- arch_dest_reloc_offset(reloc_addend(reloc));
+ arch_insn_adjusted_addend(insn, reloc);
} else {
/* non-func asm code jumping to another file */
continue;
@@ -1663,7 +1663,7 @@ static int add_call_destinations(struct objtool_file *file)
}
} else if (reloc->sym->type == STT_SECTION) {
- dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
+ dest_off = arch_insn_adjusted_addend(insn, reloc);
dest = find_call_destination(reloc->sym->sec, dest_off);
if (!dest) {
ERROR_INSN(insn, "can't find call dest symbol at %s+0x%lx",
@@ -3324,7 +3324,7 @@ static bool pv_call_dest(struct objtool_file *file, struct instruction *insn)
if (!reloc || strcmp(reloc->sym->name, "pv_ops"))
return false;
- idx = (arch_dest_reloc_offset(reloc_addend(reloc)) / sizeof(void *));
+ idx = arch_insn_adjusted_addend(insn, reloc) / sizeof(void *);
if (file->pv_ops[idx].clean)
return true;
@@ -4405,12 +4405,7 @@ static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn
reloc_offset(reloc) + 1,
(insn->offset + insn->len) - (reloc_offset(reloc) + 1))) {
- off = reloc->sym->offset;
- if (reloc_type(reloc) == R_X86_64_PC32 ||
- reloc_type(reloc) == R_X86_64_PLT32)
- off += arch_dest_reloc_offset(reloc_addend(reloc));
- else
- off += reloc_addend(reloc);
+ off = reloc->sym->offset + arch_insn_adjusted_addend(insn, reloc);
dest = find_insn(file, reloc->sym->sec, off);
if (!dest)
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index be33c7b43180a..68664625a4671 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -83,7 +83,7 @@ bool arch_callee_saved_reg(unsigned char reg);
unsigned long arch_jump_destination(struct instruction *insn);
-unsigned long arch_dest_reloc_offset(int addend);
+s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc);
const char *arch_nop_insn(int len);
const char *arch_ret_insn(int len);
--
2.50.0__pa_symbol() generates a relocation which refers to a physical address.
Convert it to back its virtual form before calculating the addend.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/arch/x86/decode.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 6742002a01f55..b10200cc50c99 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -68,6 +68,17 @@ bool arch_callee_saved_reg(unsigned char reg)
}
}
+/* Undo the effects of __pa_symbol() if necessary */
+static unsigned long phys_to_virt(unsigned long pa)
+{
+ s64 va = pa;
+
+ if (va > 0)
+ va &= ~(0x80000000);
+
+ return va;
+}
+
s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
{
s64 addend = reloc_addend(reloc);
@@ -75,7 +86,7 @@ s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
if (arch_pc_relative_reloc(reloc))
addend += insn->offset + insn->len - reloc_offset(reloc);
- return addend;
+ return phys_to_virt(addend);
}
unsigned long arch_jump_destination(struct instruction *insn)
--
2.50.0Due to the short circuiting logic in next_insn_to_validate(), control
flow may silently transition from .altinstr_replacement to .text without
a corresponding nested call to validate_branch().
As a result the validate_branch() 'sec' variable doesn't get
reinitialized, which can trigger a confusing "unexpected end of section"
warning which blames .altinstr_replacement rather than the offending
fallthrough function.
Fix that by not caching the section. There's no point in doing that
anyway.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 1165dd1669f0b..bea9b124dcf48 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3521,15 +3521,12 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
{
struct alternative *alt;
struct instruction *next_insn, *prev_insn = NULL;
- struct section *sec;
u8 visited;
int ret;
if (func && func->ignore)
return 0;
- sec = insn->sec;
-
while (1) {
next_insn = next_insn_to_validate(file, insn);
@@ -3769,7 +3766,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
WARN("%s%sunexpected end of section %s",
func ? func->name : "", func ? "(): " : "",
- sec->name);
+ insn->sec->name);
return 1;
}
--
2.50.0Add a sanity check to make sure none of the relocations for the
.discard.annotate_insn section have gone missing.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index bea9b124dcf48..fdb83a0a592a3 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2293,6 +2293,11 @@ static int read_annotate(struct objtool_file *file,
sec->sh.sh_entsize = 8;
}
+ if (sec_num_entries(sec) != sec_num_entries(sec->rsec)) {
+ ERROR("bad .discard.annotate_insn section: missing relocs");
+ return -1;
+ }
+
for_each_reloc(sec->rsec, reloc) {
type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4);
type = bswap_if_needed(file->elf, type);
--
2.50.0Use 'const char *' where applicable.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/arch/loongarch/decode.c | 2 +-
tools/objtool/arch/powerpc/decode.c | 2 +-
tools/objtool/arch/x86/decode.c | 2 +-
tools/objtool/elf.c | 6 +++---
tools/objtool/include/objtool/arch.h | 2 +-
tools/objtool/include/objtool/elf.h | 6 +++---
6 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/tools/objtool/arch/loongarch/decode.c b/tools/objtool/arch/loongarch/decode.c
index 330671d88c590..7b38718d782a7 100644
--- a/tools/objtool/arch/loongarch/decode.c
+++ b/tools/objtool/arch/loongarch/decode.c
@@ -7,7 +7,7 @@
#include <linux/objtool_types.h>
#include <arch/elf.h>
-int arch_ftrace_match(char *name)
+int arch_ftrace_match(const char *name)
{
return !strcmp(name, "_mcount");
}
diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
index 9b17885e6cba6..d4cb02120a6bd 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -9,7 +9,7 @@
#include <objtool/builtin.h>
#include <objtool/endianness.h>
-int arch_ftrace_match(char *name)
+int arch_ftrace_match(const char *name)
{
return !strcmp(name, "_mcount");
}
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index b10200cc50c99..6bb46d9981533 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -23,7 +23,7 @@
#include <objtool/builtin.h>
#include <arch/elf.h>
-int arch_ftrace_match(char *name)
+int arch_ftrace_match(const char *name)
{
return !strcmp(name, "__fentry__");
}
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d7fb3d0b05cf1..2ea6d591c3c29 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -853,7 +853,7 @@ elf_create_section_symbol(struct elf *elf, struct section *sec)
return sym;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, char *str);
+static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
struct symbol *
elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size)
@@ -1086,7 +1086,7 @@ struct elf *elf_open_read(const char *name, int flags)
return NULL;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
+static int elf_add_string(struct elf *elf, struct section *strtab, const char *str)
{
Elf_Data *data;
Elf_Scn *s;
@@ -1111,7 +1111,7 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
return -1;
}
- data->d_buf = str;
+ data->d_buf = strdup(str);
data->d_size = strlen(str) + 1;
data->d_align = 1;
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index 68664625a4671..a4502947307a4 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -71,7 +71,7 @@ struct stack_op {
struct instruction;
-int arch_ftrace_match(char *name);
+int arch_ftrace_match(const char *name);
void arch_initial_func_cfi_state(struct cfi_init_state *state);
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index df8434d3b7440..74ce454790f4d 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -40,7 +40,7 @@ struct section {
struct section *base, *rsec;
struct symbol *sym;
Elf_Data *data;
- char *name;
+ const char *name;
int idx;
bool _changed, text, rodata, noinstr, init, truncate;
struct reloc *relocs;
@@ -53,7 +53,7 @@ struct symbol {
struct elf_hash_node name_hash;
GElf_Sym sym;
struct section *sec;
- char *name;
+ const char *name;
unsigned int idx, len;
unsigned long offset;
unsigned long __subtree_last;
@@ -88,7 +88,7 @@ struct elf {
GElf_Ehdr ehdr;
int fd;
bool changed;
- char *name;
+ const char *name;
unsigned int num_files;
struct list_head sections;
unsigned long num_relocs;
--
2.50.0KBUILD_HOSTCFLAGS and KBUILD_HOSTLDFLAGS aren't defined when objtool is
built standalone. Also, the EXTRA_WARNINGS flags are rather arbitrary.
Make things simpler and more consistent by specifying compiler flags
explicitly and tweaking the warnings. Also make a few code tweaks to
make the new warnings happy.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/Makefile | 15 ++++++++++-----
tools/objtool/check.c | 4 ++--
tools/objtool/elf.c | 2 +-
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 8c20361dd100e..fc82d47f2b9a7 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -23,6 +23,11 @@ LIBELF_LIBS := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lel
all: $(OBJTOOL)
+WARNINGS := -Werror -Wall -Wextra -Wmissing-prototypes \
+ -Wmissing-declarations -Wwrite-strings \
+ -Wno-implicit-fallthrough -Wno-sign-compare \
+ -Wno-unused-parameter
+
INCLUDES := -I$(srctree)/tools/include \
-I$(srctree)/tools/include/uapi \
-I$(srctree)/tools/arch/$(HOSTARCH)/include/uapi \
@@ -30,11 +35,11 @@ INCLUDES := -I$(srctree)/tools/include \
-I$(srctree)/tools/objtool/include \
-I$(srctree)/tools/objtool/arch/$(SRCARCH)/include \
-I$(LIBSUBCMD_OUTPUT)/include
-# Note, EXTRA_WARNINGS here was determined for CC and not HOSTCC, it
-# is passed here to match a legacy behavior.
-WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed -Wno-nested-externs
-OBJTOOL_CFLAGS := -Werror $(WARNINGS) $(KBUILD_HOSTCFLAGS) -g $(INCLUDES) $(LIBELF_FLAGS)
-OBJTOOL_LDFLAGS := $(LIBELF_LIBS) $(LIBSUBCMD) $(KBUILD_HOSTLDFLAGS)
+
+OBJTOOL_CFLAGS := -std=gnu11 -fomit-frame-pointer -O2 -g \
+ $(WARNINGS) $(INCLUDES) $(LIBELF_FLAGS) $(HOSTCFLAGS)
+
+OBJTOOL_LDFLAGS := $(LIBSUBCMD) $(LIBELF_LIBS) $(HOSTLDFLAGS)
# Allow old libelf to be used:
elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(HOSTCC) $(OBJTOOL_CFLAGS) -x c -E - 2>/dev/null | grep elf_getshdr)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index fdb83a0a592a3..48b90836ed4a5 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -461,7 +461,7 @@ static int decode_instructions(struct objtool_file *file)
for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
if (!insns || idx == INSN_CHUNK_MAX) {
- insns = calloc(sizeof(*insn), INSN_CHUNK_SIZE);
+ insns = calloc(INSN_CHUNK_SIZE, sizeof(*insn));
if (!insns) {
ERROR_GLIBC("calloc");
return -1;
@@ -607,7 +607,7 @@ static int init_pv_ops(struct objtool_file *file)
return 0;
nr = sym->len / sizeof(unsigned long);
- file->pv_ops = calloc(sizeof(struct pv_state), nr);
+ file->pv_ops = calloc(nr, sizeof(struct pv_state));
if (!file->pv_ops) {
ERROR_GLIBC("calloc");
return -1;
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 2ea6d591c3c29..c27edeed2dd03 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -736,7 +736,7 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab,
}
/* setup extended section index magic and write the symbol */
- if ((shndx >= SHN_UNDEF && shndx < SHN_LORESERVE) || is_special_shndx) {
+ if (shndx < SHN_LORESERVE || is_special_shndx) {
sym->sym.st_shndx = shndx;
if (!shndx_data)
shndx = 0;
--
2.50.0The .parainstructions section no longer exists since the following
commit:
60bc276b129e ("x86/paravirt: Switch mixed paravirt/alternative calls to alternatives").
Remove the reference to it.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 48b90836ed4a5..253d52205616a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4477,7 +4477,6 @@ static int validate_ibt(struct objtool_file *file)
!strcmp(sec->name, ".altinstructions") ||
!strcmp(sec->name, ".ibt_endbr_seal") ||
!strcmp(sec->name, ".orc_unwind_ip") ||
- !strcmp(sec->name, ".parainstructions") ||
!strcmp(sec->name, ".retpoline_sites") ||
!strcmp(sec->name, ".smp_locks") ||
!strcmp(sec->name, ".static_call_sites") ||
--
2.50.0'struct objtool_file' is specific to the check code and doesn't belong
in the elf code which is supposed to be objtool_file-agnostic. Convert
the elf iterator macros to use 'struct elf' instead.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 24 ++++++++++++------------
tools/objtool/include/objtool/elf.h | 8 ++++----
tools/objtool/orc_gen.c | 2 +-
3 files changed, 17 insertions(+), 17 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 253d52205616a..6923be1b7cf34 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -106,7 +106,7 @@ static struct instruction *prev_insn_same_sym(struct objtool_file *file,
#define for_each_insn(file, insn) \
for (struct section *__sec, *__fake = (struct section *)1; \
__fake; __fake = NULL) \
- for_each_sec(file, __sec) \
+ for_each_sec(file->elf, __sec) \
sec_for_each_insn(file, __sec, insn)
#define func_for_each_insn(file, func, insn) \
@@ -431,7 +431,7 @@ static int decode_instructions(struct objtool_file *file)
unsigned long offset;
struct instruction *insn;
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
struct instruction *insns = NULL;
u8 prev_len = 0;
u8 idx = 0;
@@ -857,7 +857,7 @@ static int create_cfi_sections(struct objtool_file *file)
}
idx = 0;
- for_each_sym(file, sym) {
+ for_each_sym(file->elf, sym) {
if (sym->type != STT_FUNC)
continue;
@@ -873,7 +873,7 @@ static int create_cfi_sections(struct objtool_file *file)
return -1;
idx = 0;
- for_each_sym(file, sym) {
+ for_each_sym(file->elf, sym) {
if (sym->type != STT_FUNC)
continue;
@@ -2145,7 +2145,7 @@ static int add_jump_table_alts(struct objtool_file *file)
if (!file->rodata)
return 0;
- for_each_sym(file, func) {
+ for_each_sym(file->elf, func) {
if (func->type != STT_FUNC)
continue;
@@ -2461,7 +2461,7 @@ static int classify_symbols(struct objtool_file *file)
{
struct symbol *func;
- for_each_sym(file, func) {
+ for_each_sym(file->elf, func) {
if (func->type == STT_NOTYPE && strstarts(func->name, ".L"))
func->local_label = true;
@@ -2506,7 +2506,7 @@ static void mark_rodata(struct objtool_file *file)
*
* .rodata.str1.* sections are ignored; they don't contain jump tables.
*/
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
if ((!strncmp(sec->name, ".rodata", 7) &&
!strstr(sec->name, ".str1.")) ||
!strncmp(sec->name, ".data.rel.ro", 12)) {
@@ -4187,7 +4187,7 @@ static int add_prefix_symbols(struct objtool_file *file)
struct section *sec;
struct symbol *func;
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
if (!(sec->sh.sh_flags & SHF_EXECINSTR))
continue;
@@ -4279,7 +4279,7 @@ static int validate_functions(struct objtool_file *file)
struct section *sec;
int warnings = 0;
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
if (!(sec->sh.sh_flags & SHF_EXECINSTR))
continue;
@@ -4458,7 +4458,7 @@ static int validate_ibt(struct objtool_file *file)
for_each_insn(file, insn)
warnings += validate_ibt_insn(file, insn);
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
/* Already done by validate_ibt_insn() */
if (sec->sh.sh_flags & SHF_EXECINSTR)
@@ -4619,7 +4619,7 @@ static void disas_warned_funcs(struct objtool_file *file)
struct symbol *sym;
char *funcs = NULL, *tmp;
- for_each_sym(file, sym) {
+ for_each_sym(file->elf, sym) {
if (sym->warned) {
if (!funcs) {
funcs = malloc(strlen(sym->name) + 1);
@@ -4659,7 +4659,7 @@ static int check_abs_references(struct objtool_file *file)
struct reloc *reloc;
int ret = 0;
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
/* absolute references in non-loadable sections are fine */
if (!(sec->sh.sh_flags & SHF_ALLOC))
continue;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 74ce454790f4d..4d5f27b497249 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -325,16 +325,16 @@ static inline void set_sym_next_reloc(struct reloc *reloc, struct reloc *next)
reloc->_sym_next_reloc = (unsigned long)next | bit;
}
-#define for_each_sec(file, sec) \
- list_for_each_entry(sec, &file->elf->sections, list)
+#define for_each_sec(elf, sec) \
+ list_for_each_entry(sec, &elf->sections, list)
#define sec_for_each_sym(sec, sym) \
list_for_each_entry(sym, &sec->symbol_list, list)
-#define for_each_sym(file, sym) \
+#define for_each_sym(elf, sym) \
for (struct section *__sec, *__fake = (struct section *)1; \
__fake; __fake = NULL) \
- for_each_sec(file, __sec) \
+ for_each_sec(elf, __sec) \
sec_for_each_sym(__sec, sym)
#define for_each_reloc(rsec, reloc) \
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 922e6aac7cea7..6eff3d6a125c2 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -57,7 +57,7 @@ int orc_create(struct objtool_file *file)
/* Build a deduplicated list of ORC entries: */
INIT_LIST_HEAD(&orc_list);
- for_each_sec(file, sec) {
+ for_each_sec(file->elf, sec) {
struct orc_entry orc, prev_orc = {0};
struct instruction *insn;
bool empty = true;
--
2.50.0Add some helper macros to improve readability.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/arch/x86/special.c | 2 +-
tools/objtool/check.c | 58 ++++++++++++-------------
tools/objtool/elf.c | 20 ++++-----
tools/objtool/include/objtool/elf.h | 66 +++++++++++++++++++++++++++++
tools/objtool/special.c | 4 +-
5 files changed, 108 insertions(+), 42 deletions(-)
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 06ca4a2659a45..09300761f1085 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -89,7 +89,7 @@ struct reloc *arch_find_switch_table(struct objtool_file *file,
/* look for a relocation which references .rodata */
text_reloc = find_reloc_by_dest_range(file->elf, insn->sec,
insn->offset, insn->len);
- if (!text_reloc || text_reloc->sym->type != STT_SECTION ||
+ if (!text_reloc || !is_sec_sym(text_reloc->sym) ||
!text_reloc->sym->sec->rodata)
return NULL;
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 6923be1b7cf34..165ea9b0fdca5 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -261,7 +261,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
if (!func)
return false;
- if (func->bind == STB_GLOBAL || func->bind == STB_WEAK) {
+ if (!is_local_sym(func)) {
if (is_rust_noreturn(func))
return true;
@@ -270,7 +270,7 @@ static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
return true;
}
- if (func->bind == STB_WEAK)
+ if (is_weak_sym(func))
return false;
if (!func->len)
@@ -436,7 +436,7 @@ static int decode_instructions(struct objtool_file *file)
u8 prev_len = 0;
u8 idx = 0;
- if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+ if (!is_text_sec(sec))
continue;
if (strcmp(sec->name, ".altinstr_replacement") &&
@@ -459,7 +459,7 @@ static int decode_instructions(struct objtool_file *file)
if (!strcmp(sec->name, ".init.text") && !opts.module)
sec->init = true;
- for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
+ for (offset = 0; offset < sec_size(sec); offset += insn->len) {
if (!insns || idx == INSN_CHUNK_MAX) {
insns = calloc(INSN_CHUNK_SIZE, sizeof(*insn));
if (!insns) {
@@ -478,7 +478,7 @@ static int decode_instructions(struct objtool_file *file)
insn->offset = offset;
insn->prev_len = prev_len;
- if (arch_decode_instruction(file, sec, offset, sec->sh.sh_size - offset, insn))
+ if (arch_decode_instruction(file, sec, offset, sec_size(sec) - offset, insn))
return -1;
prev_len = insn->len;
@@ -496,12 +496,12 @@ static int decode_instructions(struct objtool_file *file)
}
sec_for_each_sym(sec, func) {
- if (func->type != STT_NOTYPE && func->type != STT_FUNC)
+ if (!is_notype_sym(func) && !is_func_sym(func))
continue;
- if (func->offset == sec->sh.sh_size) {
+ if (func->offset == sec_size(sec)) {
/* Heuristic: likely an "end" symbol */
- if (func->type == STT_NOTYPE)
+ if (is_notype_sym(func))
continue;
ERROR("%s(): STT_FUNC at end of section", func->name);
return -1;
@@ -517,7 +517,7 @@ static int decode_instructions(struct objtool_file *file)
sym_for_each_insn(file, func, insn) {
insn->sym = func;
- if (func->type == STT_FUNC &&
+ if (is_func_sym(func) &&
insn->type == INSN_ENDBR &&
list_empty(&insn->call_node)) {
if (insn->offset == func->offset) {
@@ -561,7 +561,7 @@ static int add_pv_ops(struct objtool_file *file, const char *symname)
idx = (reloc_offset(reloc) - sym->offset) / sizeof(unsigned long);
func = reloc->sym;
- if (func->type == STT_SECTION)
+ if (is_sec_sym(func))
func = find_symbol_by_offset(reloc->sym->sec,
reloc_addend(reloc));
if (!func) {
@@ -823,7 +823,7 @@ static int create_ibt_endbr_seal_sections(struct objtool_file *file)
struct symbol *sym = insn->sym;
*site = 0;
- if (opts.module && sym && sym->type == STT_FUNC &&
+ if (opts.module && sym && is_func_sym(sym) &&
insn->offset == sym->offset &&
(!strcmp(sym->name, "init_module") ||
!strcmp(sym->name, "cleanup_module"))) {
@@ -858,7 +858,7 @@ static int create_cfi_sections(struct objtool_file *file)
idx = 0;
for_each_sym(file->elf, sym) {
- if (sym->type != STT_FUNC)
+ if (!is_func_sym(sym))
continue;
if (strncmp(sym->name, "__cfi_", 6))
@@ -874,7 +874,7 @@ static int create_cfi_sections(struct objtool_file *file)
idx = 0;
for_each_sym(file->elf, sym) {
- if (sym->type != STT_FUNC)
+ if (!is_func_sym(sym))
continue;
if (strncmp(sym->name, "__cfi_", 6))
@@ -1463,7 +1463,7 @@ static bool jump_is_sibling_call(struct objtool_file *file,
return false;
/* Disallow sibling calls into STT_NOTYPE */
- if (ts->type == STT_NOTYPE)
+ if (is_notype_sym(ts))
return false;
/* Must not be self to be a sibling */
@@ -1497,7 +1497,7 @@ static int add_jump_destinations(struct objtool_file *file)
if (!reloc) {
dest_sec = insn->sec;
dest_off = arch_jump_destination(insn);
- } else if (reloc->sym->type == STT_SECTION) {
+ } else if (is_sec_sym(reloc->sym)) {
dest_sec = reloc->sym->sec;
dest_off = arch_insn_adjusted_addend(insn, reloc);
} else if (reloc->sym->retpoline_thunk) {
@@ -1657,12 +1657,12 @@ static int add_call_destinations(struct objtool_file *file)
return -1;
}
- if (func && insn_call_dest(insn)->type != STT_FUNC) {
+ if (func && !is_func_sym(insn_call_dest(insn))) {
ERROR_INSN(insn, "unsupported call to non-function");
return -1;
}
- } else if (reloc->sym->type == STT_SECTION) {
+ } else if (is_sec_sym(reloc->sym)) {
dest_off = arch_insn_adjusted_addend(insn, reloc);
dest = find_call_destination(reloc->sym->sec, dest_off);
if (!dest) {
@@ -2146,7 +2146,7 @@ static int add_jump_table_alts(struct objtool_file *file)
return 0;
for_each_sym(file->elf, func) {
- if (func->type != STT_FUNC)
+ if (!is_func_sym(func))
continue;
mark_func_jump_tables(file, func);
@@ -2185,14 +2185,14 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}
- if (sec->sh.sh_size % sizeof(struct unwind_hint)) {
+ if (sec_size(sec) % sizeof(struct unwind_hint)) {
ERROR("struct unwind_hint size mismatch");
return -1;
}
file->hints = true;
- for (i = 0; i < sec->sh.sh_size / sizeof(struct unwind_hint); i++) {
+ for (i = 0; i < sec_size(sec) / sizeof(struct unwind_hint); i++) {
hint = (struct unwind_hint *)sec->data->d_buf + i;
reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint));
@@ -2201,7 +2201,7 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}
- if (reloc->sym->type == STT_SECTION) {
+ if (is_sec_sym(reloc->sym)) {
offset = reloc_addend(reloc);
} else if (reloc->sym->local_label) {
offset = reloc->sym->offset;
@@ -2237,7 +2237,7 @@ static int read_unwind_hints(struct objtool_file *file)
if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
- if (sym && sym->bind == STB_GLOBAL) {
+ if (sym && is_global_sym(sym)) {
if (opts.ibt && insn->type != INSN_ENDBR && !insn->noendbr) {
ERROR_INSN(insn, "UNWIND_HINT_IRET_REGS without ENDBR");
return -1;
@@ -2462,10 +2462,10 @@ static int classify_symbols(struct objtool_file *file)
struct symbol *func;
for_each_sym(file->elf, func) {
- if (func->type == STT_NOTYPE && strstarts(func->name, ".L"))
+ if (is_notype_sym(func) && strstarts(func->name, ".L"))
func->local_label = true;
- if (func->bind != STB_GLOBAL)
+ if (!is_global_sym(func))
continue;
if (!strncmp(func->name, STATIC_CALL_TRAMP_PREFIX_STR,
@@ -4188,11 +4188,11 @@ static int add_prefix_symbols(struct objtool_file *file)
struct symbol *func;
for_each_sec(file->elf, sec) {
- if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+ if (!is_text_sec(sec))
continue;
sec_for_each_sym(sec, func) {
- if (func->type != STT_FUNC)
+ if (!is_func_sym(func))
continue;
add_prefix_symbol(file, func);
@@ -4236,7 +4236,7 @@ static int validate_section(struct objtool_file *file, struct section *sec)
int warnings = 0;
sec_for_each_sym(sec, func) {
- if (func->type != STT_FUNC)
+ if (!is_func_sym(func))
continue;
init_insn_state(file, &state, sec);
@@ -4280,7 +4280,7 @@ static int validate_functions(struct objtool_file *file)
int warnings = 0;
for_each_sec(file->elf, sec) {
- if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+ if (!is_text_sec(sec))
continue;
warnings += validate_section(file, sec);
@@ -4461,7 +4461,7 @@ static int validate_ibt(struct objtool_file *file)
for_each_sec(file->elf, sec) {
/* Already done by validate_ibt_insn() */
- if (sec->sh.sh_flags & SHF_EXECINSTR)
+ if (is_text_sec(sec))
continue;
if (!sec->rsec)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c27edeed2dd03..d36c0d42fd7ba 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -170,7 +170,7 @@ struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset)
struct symbol *iter;
__sym_for_each(iter, tree, offset, offset) {
- if (iter->offset == offset && iter->type != STT_SECTION)
+ if (iter->offset == offset && !is_sec_sym(iter))
return iter;
}
@@ -183,7 +183,7 @@ struct symbol *find_func_by_offset(struct section *sec, unsigned long offset)
struct symbol *iter;
__sym_for_each(iter, tree, offset, offset) {
- if (iter->offset == offset && iter->type == STT_FUNC)
+ if (iter->offset == offset && is_func_sym(iter))
return iter;
}
@@ -264,7 +264,7 @@ struct symbol *find_func_containing(struct section *sec, unsigned long offset)
struct symbol *iter;
__sym_for_each(iter, tree, offset, offset) {
- if (iter->type == STT_FUNC)
+ if (is_func_sym(iter))
return iter;
}
@@ -373,14 +373,14 @@ static int read_sections(struct elf *elf)
return -1;
}
- if (sec->sh.sh_size != 0 && !is_dwarf_section(sec)) {
+ if (sec_size(sec) != 0 && !is_dwarf_section(sec)) {
sec->data = elf_getdata(s, NULL);
if (!sec->data) {
ERROR_ELF("elf_getdata");
return -1;
}
if (sec->data->d_off != 0 ||
- sec->data->d_size != sec->sh.sh_size) {
+ sec->data->d_size != sec_size(sec)) {
ERROR("unexpected data attributes for %s", sec->name);
return -1;
}
@@ -420,7 +420,7 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
sym->type = GELF_ST_TYPE(sym->sym.st_info);
sym->bind = GELF_ST_BIND(sym->sym.st_info);
- if (sym->type == STT_FILE)
+ if (is_file_sym(sym))
elf->num_files++;
sym->offset = sym->sym.st_value;
@@ -527,7 +527,7 @@ static int read_symbols(struct elf *elf)
sec_for_each_sym(sec, sym) {
char *pname;
size_t pnamelen;
- if (sym->type != STT_FUNC)
+ if (!is_func_sym(sym))
continue;
if (sym->pfunc == NULL)
@@ -929,7 +929,7 @@ struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
struct symbol *sym = insn_sec->sym;
int addend = insn_off;
- if (!(insn_sec->sh.sh_flags & SHF_EXECINSTR)) {
+ if (!is_text_sec(insn_sec)) {
ERROR("bad call to %s() for data symbol %s", __func__, sym->name);
return NULL;
}
@@ -958,7 +958,7 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
struct symbol *sym,
s64 addend)
{
- if (sym->sec && (sec->sh.sh_flags & SHF_EXECINSTR)) {
+ if (is_text_sec(sec)) {
ERROR("bad call to %s() for text symbol %s", __func__, sym->name);
return NULL;
}
@@ -1287,7 +1287,7 @@ int elf_write_insn(struct elf *elf, struct section *sec,
*/
static int elf_truncate_section(struct elf *elf, struct section *sec)
{
- u64 size = sec->sh.sh_size;
+ u64 size = sec_size(sec);
bool truncated = false;
Elf_Data *data = NULL;
Elf_Scn *s;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 4d5f27b497249..f2dbcaa42a9c9 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -8,6 +8,7 @@
#include <stdio.h>
#include <gelf.h>
+#include <linux/string.h>
#include <linux/list.h>
#include <linux/hashtable.h>
#include <linux/rbtree.h>
@@ -178,11 +179,71 @@ static inline unsigned int elf_text_rela_type(struct elf *elf)
return elf_addr_size(elf) == 4 ? R_TEXT32 : R_TEXT64;
}
+static inline bool sym_has_sec(struct symbol *sym)
+{
+ return sym->sec->idx;
+}
+
+static inline bool is_null_sym(struct symbol *sym)
+{
+ return !sym->idx;
+}
+
+static inline bool is_sec_sym(struct symbol *sym)
+{
+ return sym->type == STT_SECTION;
+}
+
+static inline bool is_object_sym(struct symbol *sym)
+{
+ return sym->type == STT_OBJECT;
+}
+
+static inline bool is_func_sym(struct symbol *sym)
+{
+ return sym->type == STT_FUNC;
+}
+
+static inline bool is_file_sym(struct symbol *sym)
+{
+ return sym->type == STT_FILE;
+}
+
+static inline bool is_notype_sym(struct symbol *sym)
+{
+ return sym->type == STT_NOTYPE;
+}
+
+static inline bool is_global_sym(struct symbol *sym)
+{
+ return sym->bind == STB_GLOBAL;
+}
+
+static inline bool is_weak_sym(struct symbol *sym)
+{
+ return sym->bind == STB_WEAK;
+}
+
+static inline bool is_local_sym(struct symbol *sym)
+{
+ return sym->bind == STB_LOCAL;
+}
+
static inline bool is_reloc_sec(struct section *sec)
{
return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL;
}
+static inline bool is_string_sec(struct section *sec)
+{
+ return sec->sh.sh_flags & SHF_STRINGS;
+}
+
+static inline bool is_text_sec(struct section *sec)
+{
+ return sec->sh.sh_flags & SHF_EXECINSTR;
+}
+
static inline bool sec_changed(struct section *sec)
{
return sec->_changed;
@@ -223,6 +284,11 @@ static inline bool is_32bit_reloc(struct reloc *reloc)
return reloc->sec->sh.sh_entsize < 16;
}
+static inline unsigned long sec_size(struct section *sec)
+{
+ return sec->sh.sh_size;
+}
+
#define __get_reloc_field(reloc, field) \
({ \
is_32bit_reloc(reloc) ? \
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index c0beefb93b62e..fc2cf8dba1c03 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -142,12 +142,12 @@ int special_get_alts(struct elf *elf, struct list_head *alts)
if (!sec)
continue;
- if (sec->sh.sh_size % entry->size != 0) {
+ if (sec_size(sec) % entry->size != 0) {
ERROR("%s size not a multiple of %d", sec->name, entry->size);
return -1;
}
- nr_entries = sec->sh.sh_size / entry->size;
+ nr_entries = sec_size(sec) / entry->size;
for (idx = 0; idx < nr_entries; idx++) {
alt = malloc(sizeof(*alt));
--
2.50.0Introduce a flag to identify .cold subfunctions so they can be detected
easier and faster.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 14 ++++++--------
tools/objtool/elf.c | 19 ++++++++++---------
tools/objtool/include/objtool/elf.h | 1 +
3 files changed, 17 insertions(+), 17 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 165ea9b0fdca5..b548bc8146ce8 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1575,7 +1575,9 @@ static int add_jump_destinations(struct objtool_file *file)
/*
* Cross-function jump.
*/
- if (func && insn_func(jump_dest) && func != insn_func(jump_dest)) {
+
+ if (func && insn_func(jump_dest) && !func->cold &&
+ insn_func(jump_dest)->cold) {
/*
* For GCC 8+, create parent/child links for any cold
@@ -1592,11 +1594,8 @@ static int add_jump_destinations(struct objtool_file *file)
* case where the parent function's only reference to a
* subfunction is through a jump table.
*/
- if (!strstr(func->name, ".cold") &&
- strstr(insn_func(jump_dest)->name, ".cold")) {
- func->cfunc = insn_func(jump_dest);
- insn_func(jump_dest)->pfunc = func;
- }
+ func->cfunc = insn_func(jump_dest);
+ insn_func(jump_dest)->pfunc = func;
}
if (jump_is_sibling_call(file, insn, jump_dest)) {
@@ -4075,9 +4074,8 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
* If this hole jumps to a .cold function, mark it ignore too.
*/
if (insn->jump_dest && insn_func(insn->jump_dest) &&
- strstr(insn_func(insn->jump_dest)->name, ".cold")) {
+ insn_func(insn->jump_dest)->cold)
insn_func(insn->jump_dest)->ignore = true;
- }
}
return false;
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d36c0d42fd7ba..59568381486c9 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -441,6 +441,10 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
list_add(&sym->list, entry);
elf_hash_add(symbol, &sym->hash, sym->idx);
elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
+
+ if (is_func_sym(sym) && strstr(sym->name, ".cold"))
+ sym->cold = 1;
+ sym->pfunc = sym->cfunc = sym;
}
static int read_symbols(struct elf *elf)
@@ -527,18 +531,15 @@ static int read_symbols(struct elf *elf)
sec_for_each_sym(sec, sym) {
char *pname;
size_t pnamelen;
- if (!is_func_sym(sym))
+
+ if (!sym->cold)
continue;
- if (sym->pfunc == NULL)
- sym->pfunc = sym;
-
- if (sym->cfunc == NULL)
- sym->cfunc = sym;
-
coldstr = strstr(sym->name, ".cold");
- if (!coldstr)
- continue;
+ if (!coldstr) {
+ ERROR("%s(): cold subfunction without \".cold\"?", sym->name);
+ return -1;
+ }
pnamelen = coldstr - sym->name;
pname = strndup(sym->name, pnamelen);
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index f2dbcaa42a9c9..dbadcc88a3b26 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -72,6 +72,7 @@ struct symbol {
u8 frame_pointer : 1;
u8 ignore : 1;
u8 nocfi : 1;
+ u8 cold : 1;
struct list_head pv_target;
struct reloc *relocs;
struct section *group_sec;
--
2.50.0When ignore_unreachable_insn() looks for weak function holes which jump
to their .cold functions, it assumes the parent function comes before
the corresponding .cold function in the symbol table. That's not
necessarily the case with -ffunction-sections.
Mark all the holes beforehand (including .cold functions) so the
ordering of the discovery doesn't matter.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 84 ++++++++++++++-------------
tools/objtool/include/objtool/check.h | 3 +-
2 files changed, 45 insertions(+), 42 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index b548bc8146ce8..57e3b0cde19f2 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2517,6 +2517,44 @@ static void mark_rodata(struct objtool_file *file)
file->rodata = found;
}
+static void mark_holes(struct objtool_file *file)
+{
+ struct instruction *insn;
+ bool in_hole = false;
+
+ if (!opts.link)
+ return;
+
+ /*
+ * Whole archive runs might encounter dead code from weak symbols.
+ * This is where the linker will have dropped the weak symbol in
+ * favour of a regular symbol, but leaves the code in place.
+ */
+ for_each_insn(file, insn) {
+ if (insn->sym || !find_symbol_hole_containing(insn->sec, insn->offset)) {
+ in_hole = false;
+ continue;
+ }
+
+ /* Skip function padding and pfx code */
+ if (!in_hole && insn->type == INSN_NOP)
+ continue;
+
+ in_hole = true;
+ insn->hole = 1;
+
+ /*
+ * If this hole jumps to a .cold function, mark it ignore.
+ */
+ if (insn->jump_dest) {
+ struct symbol *dest_func = insn_func(insn->jump_dest);
+
+ if (dest_func && dest_func->cold)
+ dest_func->ignore = true;
+ }
+ }
+}
+
static int decode_sections(struct objtool_file *file)
{
mark_rodata(file);
@@ -2569,6 +2607,9 @@ static int decode_sections(struct objtool_file *file)
if (read_unwind_hints(file))
return -1;
+ /* Must be after add_jump_destinations() */
+ mark_holes(file);
+
/*
* Must be after add_call_destinations() such that it can override
* dead_end_function() marks.
@@ -4030,7 +4071,8 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
struct instruction *prev_insn;
int i;
- if (insn->type == INSN_NOP || insn->type == INSN_TRAP || (func && func->ignore))
+ if (insn->type == INSN_NOP || insn->type == INSN_TRAP ||
+ insn->hole || (func && func->ignore))
return true;
/*
@@ -4041,46 +4083,6 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
!strcmp(insn->sec->name, ".altinstr_aux"))
return true;
- /*
- * Whole archive runs might encounter dead code from weak symbols.
- * This is where the linker will have dropped the weak symbol in
- * favour of a regular symbol, but leaves the code in place.
- *
- * In this case we'll find a piece of code (whole function) that is not
- * covered by a !section symbol. Ignore them.
- */
- if (opts.link && !func) {
- int size = find_symbol_hole_containing(insn->sec, insn->offset);
- unsigned long end = insn->offset + size;
-
- if (!size) /* not a hole */
- return false;
-
- if (size < 0) /* hole until the end */
- return true;
-
- sec_for_each_insn_continue(file, insn) {
- /*
- * If we reach a visited instruction at or before the
- * end of the hole, ignore the unreachable.
- */
- if (insn->visited)
- return true;
-
- if (insn->offset >= end)
- break;
-
- /*
- * If this hole jumps to a .cold function, mark it ignore too.
- */
- if (insn->jump_dest && insn_func(insn->jump_dest) &&
- insn_func(insn->jump_dest)->cold)
- insn_func(insn->jump_dest)->ignore = true;
- }
-
- return false;
- }
-
if (!func)
return false;
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index 00fb745e72339..0f4e7ac929ef0 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -64,7 +64,8 @@ struct instruction {
noendbr : 1,
unret : 1,
visited : 4,
- no_reloc : 1;
+ no_reloc : 1,
+ hole : 1;
/* 10 bit hole */
struct alt_group *alt_group;
--
2.50.0In preparation for the objtool klp diff subcommand, introduce a flag to
identify __pfx_*() and __cfi_*() functions in advance so they don't need
to be manually identified every time a check is needed.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 5 +----
tools/objtool/elf.c | 7 +++++++
tools/objtool/include/objtool/elf.h | 6 ++++++
3 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 57e3b0cde19f2..6f7ed34aea43e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3577,10 +3577,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
/* Ignore KCFI type preambles, which always fall through */
- if (!strncmp(func->name, "__cfi_", 6) ||
- !strncmp(func->name, "__pfx_", 6) ||
- !strncmp(func->name, "__pi___cfi_", 11) ||
- !strncmp(func->name, "__pi___pfx_", 11))
+ if (is_prefix_func(func))
return 0;
if (file->ignore_unreachables)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 59568381486c9..775d017b1b79b 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -442,6 +442,13 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
elf_hash_add(symbol, &sym->hash, sym->idx);
elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
+ if (is_func_sym(sym) &&
+ (strstarts(sym->name, "__pfx_") ||
+ strstarts(sym->name, "__cfi_") ||
+ strstarts(sym->name, "__pi___pfx_") ||
+ strstarts(sym->name, "__pi___cfi_")))
+ sym->prefix = 1;
+
if (is_func_sym(sym) && strstr(sym->name, ".cold"))
sym->cold = 1;
sym->pfunc = sym->cfunc = sym;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index dbadcc88a3b26..79edf82e76ddf 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -73,6 +73,7 @@ struct symbol {
u8 ignore : 1;
u8 nocfi : 1;
u8 cold : 1;
+ u8 prefix : 1;
struct list_head pv_target;
struct reloc *relocs;
struct section *group_sec;
@@ -230,6 +231,11 @@ static inline bool is_local_sym(struct symbol *sym)
return sym->bind == STB_LOCAL;
}
+static inline bool is_prefix_func(struct symbol *sym)
+{
+ return sym->prefix;
+}
+
static inline bool is_reloc_sec(struct section *sec)
{
return sec->sh.sh_type == SHT_RELA || sec->sh.sh_type == SHT_REL;
--
2.50.0Simplify the relocation offset calculation in unwind_read_hints(),
similar to other conversions which have already been done.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 6f7ed34aea43e..ea53468120d7a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2200,14 +2200,7 @@ static int read_unwind_hints(struct objtool_file *file)
return -1;
}
- if (is_sec_sym(reloc->sym)) {
- offset = reloc_addend(reloc);
- } else if (reloc->sym->local_label) {
- offset = reloc->sym->offset;
- } else {
- ERROR("unexpected relocation symbol type in %s", sec->rsec->name);
- return -1;
- }
+ offset = reloc->sym->offset + reloc_addend(reloc);
insn = find_insn(file, reloc->sym->sec, offset);
if (!insn) {
--
2.50.0When a to-be-created section already exists, there's no point in
emptying the various lists if their respective sections already exist.
In fact it's better to leave them intact as they might get used later.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index ea53468120d7a..f75de86c60f5f 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -635,7 +635,6 @@ static int create_static_call_sections(struct objtool_file *file)
sec = find_section_by_name(file->elf, ".static_call_sites");
if (sec) {
- INIT_LIST_HEAD(&file->static_call_list);
WARN("file already has .static_call_sites section, skipping");
return 0;
}
@@ -851,7 +850,6 @@ static int create_cfi_sections(struct objtool_file *file)
sec = find_section_by_name(file->elf, ".cfi_sites");
if (sec) {
- INIT_LIST_HEAD(&file->call_list);
WARN("file already has .cfi_sites section, skipping");
return 0;
}
@@ -900,7 +898,6 @@ static int create_mcount_loc_sections(struct objtool_file *file)
sec = find_section_by_name(file->elf, "__mcount_loc");
if (sec) {
- INIT_LIST_HEAD(&file->mcount_loc_list);
WARN("file already has __mcount_loc section, skipping");
return 0;
}
@@ -945,7 +942,6 @@ static int create_direct_call_sections(struct objtool_file *file)
sec = find_section_by_name(file->elf, ".call_sites");
if (sec) {
- INIT_LIST_HEAD(&file->call_list);
WARN("file already has .call_sites section, skipping");
return 0;
}
--
2.50.0The objtool --Werror option name is stylistically inconsistent: halfway
between GCC's single-dash capitalized -Werror and objtool's double-dash
--lowercase convention, making it unnecessarily hard to remember.
Make the 'W' lower case (--werror) for consistency with objtool's other
options.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/Makefile.lib | 2 +-
scripts/Makefile.vmlinux_o | 2 +-
tools/objtool/builtin-check.c | 2 +-
3 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index b955602661240..15fee73e92895 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -191,7 +191,7 @@ objtool-args-$(CONFIG_HAVE_STATIC_CALL_INLINE) += --static-call
objtool-args-$(CONFIG_HAVE_UACCESS_VALIDATION) += --uaccess
objtool-args-$(or $(CONFIG_GCOV_KERNEL),$(CONFIG_KCOV)) += --no-unreachable
objtool-args-$(CONFIG_PREFIX_SYMBOLS) += --prefix=$(CONFIG_FUNCTION_PADDING_BYTES)
-objtool-args-$(CONFIG_OBJTOOL_WERROR) += --Werror
+objtool-args-$(CONFIG_OBJTOOL_WERROR) += --werror
objtool-args = $(objtool-args-y) \
$(if $(delay-objtool), --link) \
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index b024ffb3e2018..fed5200195df2 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -41,7 +41,7 @@ objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
ifeq ($(delay-objtool),y)
vmlinux-objtool-args-y += $(objtool-args-y)
else
-vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR) += --Werror
+vmlinux-objtool-args-$(CONFIG_OBJTOOL_WERROR) += --werror
endif
vmlinux-objtool-args-$(CONFIG_NOINSTR_VALIDATION) += --noinstr \
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 0f6b197cfcb03..8e2047026cc51 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -101,7 +101,7 @@ static const struct option check_options[] = {
OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
- OPT_BOOLEAN(0, "Werror", &opts.werror, "return error on warnings"),
+ OPT_BOOLEAN(0, "werror", &opts.werror, "return error on warnings"),
OPT_END(),
};
--
2.50.0The --backup option was removed with the following commit:
aa8b3e64fd39 ("objtool: Create backup on error and print args")
... which tied the backup functionality to --verbose, and only for
warnings/errors.
It's a bit inelegant and out of scope to tie that to --verbose.
Bring back the old --backup option, but with the new behavior: only on
warnings/errors, and print the args to make it easier to recreate.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/builtin-check.c | 25 +++++++++++--------------
tools/objtool/check.c | 4 +++-
tools/objtool/include/objtool/builtin.h | 3 ++-
3 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 8e2047026cc51..dcf618f47fcc5 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -92,6 +92,7 @@ static const struct option check_options[] = {
OPT_GROUP("Options:"),
OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
+ OPT_BOOLEAN(0, "backup", &opts.backup, "create backup (.orig) file on warning/error"),
OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
@@ -246,12 +247,9 @@ static void save_argv(int argc, const char **argv)
};
}
-void print_args(void)
+int make_backup(void)
{
- char *backup = NULL;
-
- if (opts.output || opts.dryrun)
- goto print;
+ char *backup;
/*
* Make a backup before kbuild deletes the file so the error
@@ -260,33 +258,32 @@ void print_args(void)
backup = malloc(strlen(objname) + strlen(ORIG_SUFFIX) + 1);
if (!backup) {
ERROR_GLIBC("malloc");
- goto print;
+ return 1;
}
strcpy(backup, objname);
strcat(backup, ORIG_SUFFIX);
- if (copy_file(objname, backup)) {
- backup = NULL;
- goto print;
- }
+ if (copy_file(objname, backup))
+ return 1;
-print:
/*
- * Print the cmdline args to make it easier to recreate. If '--output'
- * wasn't used, add it to the printed args with the backup as input.
+ * Print the cmdline args to make it easier to recreate.
*/
+
fprintf(stderr, "%s", orig_argv[0]);
for (int i = 1; i < orig_argc; i++) {
char *arg = orig_argv[i];
- if (backup && !strcmp(arg, objname))
+ /* Modify the printed args to use the backup */
+ if (!opts.output && !strcmp(arg, objname))
fprintf(stderr, " %s -o %s", backup, objname);
else
fprintf(stderr, " %s", arg);
}
fprintf(stderr, "\n");
+ return 0;
}
int objtool_run(int argc, const char **argv)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f75de86c60f5f..2af4cafb683fa 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -4833,9 +4833,11 @@ int check(struct objtool_file *file)
if (opts.verbose) {
if (opts.werror && warnings)
WARN("%d warning(s) upgraded to errors", warnings);
- print_args();
disas_warned_funcs(file);
}
+ if (opts.backup && make_backup())
+ return 1;
+
return ret;
}
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index ab22673862e1b..7d559a2c13b7b 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -30,6 +30,7 @@ struct opts {
/* options: */
bool backtrace;
+ bool backup;
bool dryrun;
bool link;
bool mnop;
@@ -48,6 +49,6 @@ int cmd_parse_options(int argc, const char **argv, const char * const usage[]);
int objtool_run(int argc, const char **argv);
-void print_args(void);
+int make_backup(void);
#endif /* _BUILTIN_H */
--
2.50.0Bring the cmdline check_options[] array back into vertical alignment for
better readability.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/builtin-check.c | 54 +++++++++++++++++------------------
1 file changed, 27 insertions(+), 27 deletions(-)
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index dcf618f47fcc5..e7a8f58f5630c 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -73,36 +73,36 @@ static int parse_hacks(const struct option *opt, const char *str, int unset)
static const struct option check_options[] = {
OPT_GROUP("Actions:"),
+ OPT_BOOLEAN(0, "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
- OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
- OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
- OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
- OPT_BOOLEAN(0, "orc", &opts.orc, "generate ORC metadata"),
- OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
- OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
- OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"),
- OPT_INTEGER(0, "prefix", &opts.prefix, "generate prefix symbols"),
- OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
- OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
- OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
- OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
- OPT_BOOLEAN(0 , "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
- OPT_BOOLEAN(0 , "noabs", &opts.noabs, "reject absolute references in allocatable sections"),
- OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
+ OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
+ OPT_BOOLEAN('m', "mcount", &opts.mcount, "annotate mcount/fentry calls for ftrace"),
+ OPT_BOOLEAN(0, "noabs", &opts.noabs, "reject absolute references in allocatable sections"),
+ OPT_BOOLEAN('n', "noinstr", &opts.noinstr, "validate noinstr rules"),
+ OPT_BOOLEAN(0, "orc", &opts.orc, "generate ORC metadata"),
+ OPT_BOOLEAN('r', "retpoline", &opts.retpoline, "validate and annotate retpoline usage"),
+ OPT_BOOLEAN(0, "rethunk", &opts.rethunk, "validate and annotate rethunk usage"),
+ OPT_BOOLEAN(0, "unret", &opts.unret, "validate entry unret placement"),
+ OPT_INTEGER(0, "prefix", &opts.prefix, "generate prefix symbols"),
+ OPT_BOOLEAN('l', "sls", &opts.sls, "validate straight-line-speculation mitigations"),
+ OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
+ OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
+ OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
+ OPT_CALLBACK_OPTARG(0, "dump", NULL, NULL, "orc", "dump metadata", parse_dump),
OPT_GROUP("Options:"),
- OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
- OPT_BOOLEAN(0, "backup", &opts.backup, "create backup (.orig) file on warning/error"),
- OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
- OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
- OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
- OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
- OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
- OPT_STRING('o', "output", &opts.output, "file", "output file name"),
- OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
- OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
- OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
- OPT_BOOLEAN(0, "werror", &opts.werror, "return error on warnings"),
+ OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
+ OPT_BOOLEAN(0, "backup", &opts.backup, "create backup (.orig) file on warning/error"),
+ OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
+ OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
+ OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
+ OPT_BOOLEAN(0, "mnop", &opts.mnop, "nop out mcount call sites"),
+ OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"),
+ OPT_STRING('o', "output", &opts.output, "file", "output file name"),
+ OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"),
+ OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"),
+ OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"),
+ OPT_BOOLEAN(0, "werror", &opts.werror, "return error on warnings"),
OPT_END(),
};
--
2.50.0The add_jump_destinations() logic is a bit weird and convoluted after
being incrementally tweaked over the years. Refactor it to hopefully be
more logical and straightforward.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 222 +++++++++++++---------------
tools/objtool/include/objtool/elf.h | 4 +-
2 files changed, 106 insertions(+), 120 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 2af4cafb683fa..6d21b83b9377a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1423,9 +1423,14 @@ static void add_return_call(struct objtool_file *file, struct instruction *insn,
}
static bool is_first_func_insn(struct objtool_file *file,
- struct instruction *insn, struct symbol *sym)
+ struct instruction *insn)
{
- if (insn->offset == sym->offset)
+ struct symbol *func = insn_func(insn);
+
+ if (!func)
+ return false;
+
+ if (insn->offset == func->offset)
return true;
/* Allow direct CALL/JMP past ENDBR */
@@ -1433,51 +1438,30 @@ static bool is_first_func_insn(struct objtool_file *file,
struct instruction *prev = prev_insn_same_sym(file, insn);
if (prev && prev->type == INSN_ENDBR &&
- insn->offset == sym->offset + prev->len)
+ insn->offset == func->offset + prev->len)
return true;
}
return false;
}
-/*
- * A sibling call is a tail-call to another symbol -- to differentiate from a
- * recursive tail-call which is to the same symbol.
- */
-static bool jump_is_sibling_call(struct objtool_file *file,
- struct instruction *from, struct instruction *to)
-{
- struct symbol *fs = from->sym;
- struct symbol *ts = to->sym;
-
- /* Not a sibling call if from/to a symbol hole */
- if (!fs || !ts)
- return false;
-
- /* Not a sibling call if not targeting the start of a symbol. */
- if (!is_first_func_insn(file, to, ts))
- return false;
-
- /* Disallow sibling calls into STT_NOTYPE */
- if (is_notype_sym(ts))
- return false;
-
- /* Must not be self to be a sibling */
- return fs->pfunc != ts->pfunc;
-}
-
/*
* Find the destination instructions for all jumps.
*/
static int add_jump_destinations(struct objtool_file *file)
{
- struct instruction *insn, *jump_dest;
+ struct instruction *insn;
struct reloc *reloc;
- struct section *dest_sec;
- unsigned long dest_off;
for_each_insn(file, insn) {
struct symbol *func = insn_func(insn);
+ struct instruction *dest_insn;
+ struct section *dest_sec;
+ struct symbol *dest_sym;
+ unsigned long dest_off;
+
+ if (!is_static_jump(insn))
+ continue;
if (insn->jump_dest) {
/*
@@ -1486,51 +1470,53 @@ static int add_jump_destinations(struct objtool_file *file)
*/
continue;
}
- if (!is_static_jump(insn))
- continue;
reloc = insn_reloc(file, insn);
if (!reloc) {
dest_sec = insn->sec;
dest_off = arch_jump_destination(insn);
- } else if (is_sec_sym(reloc->sym)) {
- dest_sec = reloc->sym->sec;
- dest_off = arch_insn_adjusted_addend(insn, reloc);
- } else if (reloc->sym->retpoline_thunk) {
- if (add_retpoline_call(file, insn))
- return -1;
- continue;
- } else if (reloc->sym->return_thunk) {
- add_return_call(file, insn, true);
- continue;
- } else if (func) {
- /*
- * External sibling call or internal sibling call with
- * STT_FUNC reloc.
- */
- if (add_call_dest(file, insn, reloc->sym, true))
- return -1;
- continue;
- } else if (reloc->sym->sec->idx) {
- dest_sec = reloc->sym->sec;
- dest_off = reloc->sym->sym.st_value +
- arch_insn_adjusted_addend(insn, reloc);
+ dest_sym = dest_sec->sym;
} else {
- /* non-func asm code jumping to another file */
- continue;
+ dest_sym = reloc->sym;
+ if (is_undef_sym(dest_sym)) {
+ if (dest_sym->retpoline_thunk) {
+ if (add_retpoline_call(file, insn))
+ return -1;
+ continue;
+ }
+
+ if (dest_sym->return_thunk) {
+ add_return_call(file, insn, true);
+ continue;
+ }
+
+ /* External symbol */
+ if (func) {
+ /* External sibling call */
+ if (add_call_dest(file, insn, dest_sym, true))
+ return -1;
+ continue;
+ }
+
+ /* Non-func asm code jumping to external symbol */
+ continue;
+ }
+
+ dest_sec = dest_sym->sec;
+ dest_off = dest_sym->offset + arch_insn_adjusted_addend(insn, reloc);
}
- jump_dest = find_insn(file, dest_sec, dest_off);
- if (!jump_dest) {
+ dest_insn = find_insn(file, dest_sec, dest_off);
+ if (!dest_insn) {
struct symbol *sym = find_symbol_by_offset(dest_sec, dest_off);
/*
- * This is a special case for retbleed_untrain_ret().
- * It jumps to __x86_return_thunk(), but objtool
- * can't find the thunk's starting RET
- * instruction, because the RET is also in the
- * middle of another instruction. Objtool only
- * knows about the outer instruction.
+ * retbleed_untrain_ret() jumps to
+ * __x86_return_thunk(), but objtool can't find
+ * the thunk's starting RET instruction,
+ * because the RET is also in the middle of
+ * another instruction. Objtool only knows
+ * about the outer instruction.
*/
if (sym && sym->embedded_insn) {
add_return_call(file, insn, false);
@@ -1538,73 +1524,73 @@ static int add_jump_destinations(struct objtool_file *file)
}
/*
- * GCOV/KCOV dead code can jump to the end of the
- * function/section.
+ * GCOV/KCOV dead code can jump to the end of
+ * the function/section.
*/
if (file->ignore_unreachables && func &&
dest_sec == insn->sec &&
dest_off == func->offset + func->len)
continue;
- ERROR_INSN(insn, "can't find jump dest instruction at %s+0x%lx",
- dest_sec->name, dest_off);
+ ERROR_INSN(insn, "can't find jump dest instruction at %s",
+ offstr(dest_sec, dest_off));
return -1;
}
- /*
- * An intra-TU jump in retpoline.o might not have a relocation
- * for its jump dest, in which case the above
- * add_{retpoline,return}_call() didn't happen.
- */
- if (jump_dest->sym && jump_dest->offset == jump_dest->sym->offset) {
- if (jump_dest->sym->retpoline_thunk) {
- if (add_retpoline_call(file, insn))
- return -1;
- continue;
- }
- if (jump_dest->sym->return_thunk) {
- add_return_call(file, insn, true);
- continue;
- }
+ if (!dest_sym || is_sec_sym(dest_sym)) {
+ dest_sym = dest_insn->sym;
+ if (!dest_sym)
+ goto set_jump_dest;
}
- /*
- * Cross-function jump.
- */
-
- if (func && insn_func(jump_dest) && !func->cold &&
- insn_func(jump_dest)->cold) {
-
- /*
- * For GCC 8+, create parent/child links for any cold
- * subfunctions. This is _mostly_ redundant with a
- * similar initialization in read_symbols().
- *
- * If a function has aliases, we want the *first* such
- * function in the symbol table to be the subfunction's
- * parent. In that case we overwrite the
- * initialization done in read_symbols().
- *
- * However this code can't completely replace the
- * read_symbols() code because this doesn't detect the
- * case where the parent function's only reference to a
- * subfunction is through a jump table.
- */
- func->cfunc = insn_func(jump_dest);
- insn_func(jump_dest)->pfunc = func;
- }
-
- if (jump_is_sibling_call(file, insn, jump_dest)) {
- /*
- * Internal sibling call without reloc or with
- * STT_SECTION reloc.
- */
- if (add_call_dest(file, insn, insn_func(jump_dest), true))
+ if (dest_sym->retpoline_thunk && dest_insn->offset == dest_sym->offset) {
+ if (add_retpoline_call(file, insn))
return -1;
continue;
}
- insn->jump_dest = jump_dest;
+ if (dest_sym->return_thunk && dest_insn->offset == dest_sym->offset) {
+ add_return_call(file, insn, true);
+ continue;
+ }
+
+ if (!insn->sym || insn->sym == dest_insn->sym)
+ goto set_jump_dest;
+
+ /*
+ * Internal cross-function jump.
+ */
+
+ /*
+ * For GCC 8+, create parent/child links for any cold
+ * subfunctions. This is _mostly_ redundant with a
+ * similar initialization in read_symbols().
+ *
+ * If a function has aliases, we want the *first* such
+ * function in the symbol table to be the subfunction's
+ * parent. In that case we overwrite the
+ * initialization done in read_symbols().
+ *
+ * However this code can't completely replace the
+ * read_symbols() code because this doesn't detect the
+ * case where the parent function's only reference to a
+ * subfunction is through a jump table.
+ */
+ if (func && dest_sym->cold) {
+ func->cfunc = dest_sym;
+ dest_sym->pfunc = func;
+ goto set_jump_dest;
+ }
+
+ if (is_first_func_insn(file, dest_insn)) {
+ /* Internal sibling call */
+ if (add_call_dest(file, insn, dest_sym, true))
+ return -1;
+ continue;
+ }
+
+set_jump_dest:
+ insn->jump_dest = dest_insn;
}
return 0;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 79edf82e76ddf..07fc41f574b90 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -181,9 +181,9 @@ static inline unsigned int elf_text_rela_type(struct elf *elf)
return elf_addr_size(elf) == 4 ? R_TEXT32 : R_TEXT64;
}
-static inline bool sym_has_sec(struct symbol *sym)
+static inline bool is_undef_sym(struct symbol *sym)
{
- return sym->sec->idx;
+ return !sym->sec->idx;
}
static inline bool is_null_sym(struct symbol *sym)
--
2.50.0!sym->sec isn't actually a thing: even STT_UNDEF and other special
symbol types belong to NULL section 0.
Simplify the initialization of 'shndx' accordingly.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 775d017b1b79b..c35726a47c07c 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -637,7 +637,7 @@ static int elf_update_sym_relocs(struct elf *elf, struct symbol *sym)
static int elf_update_symbol(struct elf *elf, struct section *symtab,
struct section *symtab_shndx, struct symbol *sym)
{
- Elf32_Word shndx = sym->sec ? sym->sec->idx : SHN_UNDEF;
+ Elf32_Word shndx;
Elf_Data *symtab_data = NULL, *shndx_data = NULL;
Elf64_Xword entsize = symtab->sh.sh_entsize;
int max_idx, idx = sym->idx;
@@ -645,8 +645,7 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab,
bool is_special_shndx = sym->sym.st_shndx >= SHN_LORESERVE &&
sym->sym.st_shndx != SHN_XINDEX;
- if (is_special_shndx)
- shndx = sym->sym.st_shndx;
+ shndx = is_special_shndx ? sym->sym.st_shndx : sym->sec->idx;
s = elf_getscn(elf->elf, symtab->idx);
if (!s) {
--
2.50.0In preparation for the objtool klp diff subcommand, broaden the
elf_create_symbol() interface to give callers more control and reduce
duplication of some subtle setup logic.
While at it, make elf_create_symbol() and elf_create_section_symbol()
global so sections can be created by the upcoming klp diff code.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 111 +++++++++++++++-------------
tools/objtool/include/objtool/elf.h | 11 ++-
2 files changed, 69 insertions(+), 53 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index c35726a47c07c..d7703c848ce02 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -763,24 +763,60 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab,
return 0;
}
-static struct symbol *
-__elf_create_symbol(struct elf *elf, struct symbol *sym)
+static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
+
+struct symbol *elf_create_symbol(struct elf *elf, const char *name,
+ struct section *sec, unsigned int bind,
+ unsigned int type, unsigned long offset,
+ size_t size)
{
struct section *symtab, *symtab_shndx;
Elf32_Word first_non_local, new_idx;
- struct symbol *old;
+ struct symbol *old, *sym;
+
+ sym = calloc(1, sizeof(*sym));
+ if (!sym) {
+ ERROR_GLIBC("calloc");
+ return NULL;
+ }
+
+ sym->name = strdup(name);
+ if (!sym->name) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
+ if (type != STT_SECTION) {
+ sym->sym.st_name = elf_add_string(elf, NULL, sym->name);
+ if (sym->sym.st_name == -1)
+ return NULL;
+ }
+
+ if (sec) {
+ sym->sec = sec;
+ } else {
+ sym->sec = find_section_by_index(elf, 0);
+ if (!sym->sec) {
+ ERROR("no NULL section");
+ return NULL;
+ }
+ }
+
+ sym->sym.st_info = GELF_ST_INFO(bind, type);
+ sym->sym.st_value = offset;
+ sym->sym.st_size = size;
symtab = find_section_by_name(elf, ".symtab");
- if (symtab) {
- symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
- } else {
+ if (!symtab) {
ERROR("no .symtab");
return NULL;
}
+ symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
+
new_idx = sec_num_entries(symtab);
- if (GELF_ST_BIND(sym->sym.st_info) != STB_LOCAL)
+ if (bind != STB_LOCAL)
goto non_local;
/*
@@ -818,10 +854,8 @@ __elf_create_symbol(struct elf *elf, struct symbol *sym)
non_local:
sym->idx = new_idx;
- if (elf_update_symbol(elf, symtab, symtab_shndx, sym)) {
- ERROR("elf_update_symbol");
+ if (sym->idx && elf_update_symbol(elf, symtab, symtab_shndx, sym))
return NULL;
- }
symtab->sh.sh_size += symtab->sh.sh_entsize;
mark_sec_changed(elf, symtab, true);
@@ -831,64 +865,39 @@ __elf_create_symbol(struct elf *elf, struct symbol *sym)
mark_sec_changed(elf, symtab_shndx, true);
}
+ elf_add_symbol(elf, sym);
+
return sym;
}
-static struct symbol *
-elf_create_section_symbol(struct elf *elf, struct section *sec)
+struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec)
{
struct symbol *sym = calloc(1, sizeof(*sym));
- if (!sym) {
- ERROR_GLIBC("malloc");
+ sym = elf_create_symbol(elf, sec->name, sec, STB_LOCAL, STT_SECTION, 0, 0);
+ if (!sym)
return NULL;
- }
- sym->name = sec->name;
- sym->sec = sec;
-
- // st_name 0
- sym->sym.st_info = GELF_ST_INFO(STB_LOCAL, STT_SECTION);
- // st_other 0
- // st_value 0
- // st_size 0
-
- sym = __elf_create_symbol(elf, sym);
- if (sym)
- elf_add_symbol(elf, sym);
+ sec->sym = sym;
return sym;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
-
struct symbol *
-elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size)
+elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, size_t size)
{
- struct symbol *sym = calloc(1, sizeof(*sym));
size_t namelen = strlen(orig->name) + sizeof("__pfx_");
- char *name = malloc(namelen);
-
- if (!sym || !name) {
- ERROR_GLIBC("malloc");
- return NULL;
- }
+ char name[SYM_NAME_LEN];
+ unsigned long offset;
snprintf(name, namelen, "__pfx_%s", orig->name);
- sym->name = name;
- sym->sec = orig->sec;
+ offset = orig->sym.st_value - size;
- sym->sym.st_name = elf_add_string(elf, NULL, name);
- sym->sym.st_info = orig->sym.st_info;
- sym->sym.st_value = orig->sym.st_value - size;
- sym->sym.st_size = size;
-
- sym = __elf_create_symbol(elf, sym);
- if (sym)
- elf_add_symbol(elf, sym);
-
- return sym;
+ return elf_create_symbol(elf, name, orig->sec,
+ GELF_ST_BIND(orig->sym.st_info),
+ GELF_ST_TYPE(orig->sym.st_info),
+ offset, size);
}
static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
@@ -934,7 +943,7 @@ struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
unsigned long insn_off)
{
struct symbol *sym = insn_sec->sym;
- int addend = insn_off;
+ s64 addend = insn_off;
if (!is_text_sec(insn_sec)) {
ERROR("bad call to %s() for data symbol %s", __func__, sym->name);
@@ -951,8 +960,6 @@ struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
sym = elf_create_section_symbol(elf, insn_sec);
if (!sym)
return NULL;
-
- insn_sec->sym = sym;
}
return elf_init_reloc(elf, sec->rsec, reloc_idx, offset, sym, addend,
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 07fc41f574b90..c33b8fa0e3cec 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -15,6 +15,8 @@
#include <linux/jhash.h>
#include <arch/elf.h>
+#define SYM_NAME_LEN 512
+
#ifdef LIBELF_USE_DEPRECATED
# define elf_getshdrnum elf_getshnum
# define elf_getshdrstrndx elf_getshstrndx
@@ -120,7 +122,14 @@ struct section *elf_create_section_pair(struct elf *elf, const char *name,
size_t entsize, unsigned int nr,
unsigned int reloc_nr);
-struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, long size);
+struct symbol *elf_create_symbol(struct elf *elf, const char *name,
+ struct section *sec, unsigned int bind,
+ unsigned int type, unsigned long offset,
+ size_t size);
+struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec);
+struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,
+ size_t size);
+
struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
unsigned long offset,
--
2.50.0In preparation for the objtool klp diff subcommand, broaden the
elf_create_section() interface to give callers more control and reduce
duplication of some subtle setup logic.
While at it, make elf_create_rela_section() global so sections can be
created by the upcoming klp diff code.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 118 ++++++++++++++++------------
tools/objtool/include/objtool/elf.h | 7 +-
tools/objtool/orc_gen.c | 6 +-
3 files changed, 77 insertions(+), 54 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index d7703c848ce02..7a7e63c7153f4 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -1138,51 +1138,53 @@ static int elf_add_string(struct elf *elf, struct section *strtab, const char *s
}
struct section *elf_create_section(struct elf *elf, const char *name,
- size_t entsize, unsigned int nr)
+ size_t size, size_t entsize,
+ unsigned int type, unsigned int align,
+ unsigned int flags)
{
struct section *sec, *shstrtab;
- size_t size = entsize * nr;
Elf_Scn *s;
- sec = malloc(sizeof(*sec));
- if (!sec) {
- ERROR_GLIBC("malloc");
+ if (name && find_section_by_name(elf, name)) {
+ ERROR("section '%s' already exists", name);
+ return NULL;
+ }
+
+ sec = calloc(1, sizeof(*sec));
+ if (!sec) {
+ ERROR_GLIBC("calloc");
return NULL;
}
- memset(sec, 0, sizeof(*sec));
INIT_LIST_HEAD(&sec->symbol_list);
+ /* don't actually create the section, just the data structures */
+ if (type == SHT_NULL)
+ goto add;
+
s = elf_newscn(elf->elf);
if (!s) {
ERROR_ELF("elf_newscn");
return NULL;
}
- sec->name = strdup(name);
- if (!sec->name) {
- ERROR_GLIBC("strdup");
- return NULL;
- }
-
sec->idx = elf_ndxscn(s);
- sec->data = elf_newdata(s);
- if (!sec->data) {
- ERROR_ELF("elf_newdata");
- return NULL;
- }
-
- sec->data->d_size = size;
- sec->data->d_align = 1;
-
if (size) {
- sec->data->d_buf = malloc(size);
- if (!sec->data->d_buf) {
- ERROR_GLIBC("malloc");
+ sec->data = elf_newdata(s);
+ if (!sec->data) {
+ ERROR_ELF("elf_newdata");
+ return NULL;
+ }
+
+ sec->data->d_size = size;
+ sec->data->d_align = 1;
+
+ sec->data->d_buf = calloc(1, size);
+ if (!sec->data->d_buf) {
+ ERROR_GLIBC("calloc");
return NULL;
}
- memset(sec->data->d_buf, 0, size);
}
if (!gelf_getshdr(s, &sec->sh)) {
@@ -1192,34 +1194,44 @@ struct section *elf_create_section(struct elf *elf, const char *name,
sec->sh.sh_size = size;
sec->sh.sh_entsize = entsize;
- sec->sh.sh_type = SHT_PROGBITS;
- sec->sh.sh_addralign = 1;
- sec->sh.sh_flags = SHF_ALLOC;
+ sec->sh.sh_type = type;
+ sec->sh.sh_addralign = align;
+ sec->sh.sh_flags = flags;
- /* Add section name to .shstrtab (or .strtab for Clang) */
- shstrtab = find_section_by_name(elf, ".shstrtab");
- if (!shstrtab)
- shstrtab = find_section_by_name(elf, ".strtab");
- if (!shstrtab) {
- ERROR("can't find .shstrtab or .strtab section");
- return NULL;
+ if (name) {
+ sec->name = strdup(name);
+ if (!sec->name) {
+ ERROR("strdup");
+ return NULL;
+ }
+
+ /* Add section name to .shstrtab (or .strtab for Clang) */
+ shstrtab = find_section_by_name(elf, ".shstrtab");
+ if (!shstrtab) {
+ shstrtab = find_section_by_name(elf, ".strtab");
+ if (!shstrtab) {
+ ERROR("can't find .shstrtab or .strtab");
+ return NULL;
+ }
+ }
+ sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);
+ if (sec->sh.sh_name == -1)
+ return NULL;
+
+ elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
}
- sec->sh.sh_name = elf_add_string(elf, shstrtab, sec->name);
- if (sec->sh.sh_name == -1)
- return NULL;
+add:
list_add_tail(&sec->list, &elf->sections);
elf_hash_add(section, &sec->hash, sec->idx);
- elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
mark_sec_changed(elf, sec, true);
return sec;
}
-static struct section *elf_create_rela_section(struct elf *elf,
- struct section *sec,
- unsigned int reloc_nr)
+struct section *elf_create_rela_section(struct elf *elf, struct section *sec,
+ unsigned int reloc_nr)
{
struct section *rsec;
char *rsec_name;
@@ -1232,22 +1244,23 @@ static struct section *elf_create_rela_section(struct elf *elf,
strcpy(rsec_name, ".rela");
strcat(rsec_name, sec->name);
- rsec = elf_create_section(elf, rsec_name, elf_rela_size(elf), reloc_nr);
+ rsec = elf_create_section(elf, rsec_name, reloc_nr * elf_rela_size(elf),
+ elf_rela_size(elf), SHT_RELA, elf_addr_size(elf),
+ SHF_INFO_LINK);
free(rsec_name);
if (!rsec)
return NULL;
- rsec->data->d_type = ELF_T_RELA;
- rsec->sh.sh_type = SHT_RELA;
- rsec->sh.sh_addralign = elf_addr_size(elf);
rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
rsec->sh.sh_info = sec->idx;
- rsec->sh.sh_flags = SHF_INFO_LINK;
- rsec->relocs = calloc(sec_num_entries(rsec), sizeof(struct reloc));
- if (!rsec->relocs) {
- ERROR_GLIBC("calloc");
- return NULL;
+ if (reloc_nr) {
+ rsec->data->d_type = ELF_T_RELA;
+ rsec->relocs = calloc(sec_num_entries(rsec), sizeof(struct reloc));
+ if (!rsec->relocs) {
+ ERROR_GLIBC("calloc");
+ return NULL;
+ }
}
sec->rsec = rsec;
@@ -1262,7 +1275,8 @@ struct section *elf_create_section_pair(struct elf *elf, const char *name,
{
struct section *sec;
- sec = elf_create_section(elf, name, entsize, nr);
+ sec = elf_create_section(elf, name, nr * entsize, entsize,
+ SHT_PROGBITS, 1, SHF_ALLOC);
if (!sec)
return NULL;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index c33b8fa0e3cec..badb10926d1e9 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -117,11 +117,16 @@ struct elf {
struct elf *elf_open_read(const char *name, int flags);
struct section *elf_create_section(struct elf *elf, const char *name,
- size_t entsize, unsigned int nr);
+ size_t size, size_t entsize,
+ unsigned int type, unsigned int align,
+ unsigned int flags);
struct section *elf_create_section_pair(struct elf *elf, const char *name,
size_t entsize, unsigned int nr,
unsigned int reloc_nr);
+struct section *elf_create_rela_section(struct elf *elf, struct section *sec,
+ unsigned int reloc_nr);
+
struct symbol *elf_create_symbol(struct elf *elf, const char *name,
struct section *sec, unsigned int bind,
unsigned int type, unsigned long offset,
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 6eff3d6a125c2..9d380abc2ed35 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -127,7 +127,11 @@ int orc_create(struct objtool_file *file)
return -1;
}
orc_sec = elf_create_section(file->elf, ".orc_unwind",
- sizeof(struct orc_entry), nr);
+ nr * sizeof(struct orc_entry),
+ sizeof(struct orc_entry),
+ SHT_PROGBITS,
+ 1,
+ SHF_ALLOC);
if (!orc_sec)
return -1;
--
2.50.0In preparation for the objtool klp diff subcommand, refactor
elf_add_string() by adding a new elf_add_data() helper which allows the
adding of arbitrary data to a section.
Make both interfaces global so they can be used by the upcoming klp diff
code.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 66 ++++++++++++++++++++---------
tools/objtool/include/objtool/elf.h | 10 +++--
2 files changed, 54 insertions(+), 22 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 7a7e63c7153f4..117a1b5915a14 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -18,10 +18,11 @@
#include <errno.h>
#include <linux/interval_tree_generic.h>
#include <objtool/builtin.h>
-
#include <objtool/elf.h>
#include <objtool/warn.h>
+#define ALIGN_UP(x, align_to) (((x) + ((align_to)-1)) & ~((align_to)-1))
+
static inline u32 str_hash(const char *str)
{
return jhash(str, strlen(str), 0);
@@ -763,8 +764,6 @@ static int elf_update_symbol(struct elf *elf, struct section *symtab,
return 0;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
-
struct symbol *elf_create_symbol(struct elf *elf, const char *name,
struct section *sec, unsigned int bind,
unsigned int type, unsigned long offset,
@@ -1100,11 +1099,9 @@ struct elf *elf_open_read(const char *name, int flags)
return NULL;
}
-static int elf_add_string(struct elf *elf, struct section *strtab, const char *str)
+unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str)
{
- Elf_Data *data;
- Elf_Scn *s;
- int len;
+ unsigned int offset;
if (!strtab)
strtab = find_section_by_name(elf, ".strtab");
@@ -1113,28 +1110,59 @@ static int elf_add_string(struct elf *elf, struct section *strtab, const char *s
return -1;
}
- s = elf_getscn(elf->elf, strtab->idx);
+ if (!strtab->sh.sh_addralign) {
+ ERROR("'%s': invalid sh_addralign", strtab->name);
+ return -1;
+ }
+
+ offset = ALIGN_UP(strtab->sh.sh_size, strtab->sh.sh_addralign);
+
+ if (!elf_add_data(elf, strtab, str, strlen(str) + 1))
+ return -1;
+
+ return offset;
+}
+
+void *elf_add_data(struct elf *elf, struct section *sec, const void *data, size_t size)
+{
+ unsigned long offset;
+ Elf_Scn *s;
+
+ if (!sec->sh.sh_addralign) {
+ ERROR("'%s': invalid sh_addralign", sec->name);
+ return NULL;
+ }
+
+ s = elf_getscn(elf->elf, sec->idx);
if (!s) {
ERROR_ELF("elf_getscn");
- return -1;
+ return NULL;
}
- data = elf_newdata(s);
- if (!data) {
+ sec->data = elf_newdata(s);
+ if (!sec->data) {
ERROR_ELF("elf_newdata");
- return -1;
+ return NULL;
}
- data->d_buf = strdup(str);
- data->d_size = strlen(str) + 1;
- data->d_align = 1;
+ sec->data->d_buf = calloc(1, size);
+ if (!sec->data->d_buf) {
+ ERROR_GLIBC("calloc");
+ return NULL;
+ }
- len = strtab->sh.sh_size;
- strtab->sh.sh_size += data->d_size;
+ if (data)
+ memcpy(sec->data->d_buf, data, size);
- mark_sec_changed(elf, strtab, true);
+ sec->data->d_size = size;
+ sec->data->d_align = 1;
- return len;
+ offset = ALIGN_UP(sec->sh.sh_size, sec->sh.sh_addralign);
+ sec->sh.sh_size = offset + size;
+
+ mark_sec_changed(elf, sec, true);
+
+ return sec->data->d_buf;
}
struct section *elf_create_section(struct elf *elf, const char *name,
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index badb10926d1e9..0d9aeefb6d124 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -135,6 +135,10 @@ struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec);
struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,
size_t size);
+void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
+ size_t size);
+
+unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
unsigned long offset,
@@ -148,9 +152,9 @@ struct reloc *elf_init_reloc_data_sym(struct elf *elf, struct section *sec,
struct symbol *sym,
s64 addend);
-int elf_write_insn(struct elf *elf, struct section *sec,
- unsigned long offset, unsigned int len,
- const char *insn);
+int elf_write_insn(struct elf *elf, struct section *sec, unsigned long offset,
+ unsigned int len, const char *insn);
+
int elf_write(struct elf *elf);
void elf_close(struct elf *elf);
--
2.50.0elf_create_rela_section() is quite limited in that it requires the
caller to know how many relocations need to be allocated up front.
In preparation for the objtool klp diff subcommand, allow an arbitrary
number of relocations to be created and initialized on demand after
section creation.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/elf.c | 170 +++++++++++++++++++++++++---
tools/objtool/include/objtool/elf.h | 9 ++
2 files changed, 165 insertions(+), 14 deletions(-)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 117a1b5915a14..8d01fc3b4f679 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -22,6 +22,8 @@
#include <objtool/warn.h>
#define ALIGN_UP(x, align_to) (((x) + ((align_to)-1)) & ~((align_to)-1))
+#define ALIGN_UP_POW2(x) (1U << ((8 * sizeof(x)) - __builtin_clz((x) - 1U)))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
static inline u32 str_hash(const char *str)
{
@@ -899,10 +901,9 @@ elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, size_t size)
offset, size);
}
-static struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
- unsigned int reloc_idx,
- unsigned long offset, struct symbol *sym,
- s64 addend, unsigned int type)
+struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
+ unsigned int reloc_idx, unsigned long offset,
+ struct symbol *sym, s64 addend, unsigned int type)
{
struct reloc *reloc, empty = { 0 };
@@ -1004,12 +1005,16 @@ static int read_relocs(struct elf *elf)
rsec->base->rsec = rsec;
- nr_reloc = 0;
+ /* nr_alloc_relocs=0: libelf owns d_buf */
+ rsec->nr_alloc_relocs = 0;
+
rsec->relocs = calloc(sec_num_entries(rsec), sizeof(*reloc));
if (!rsec->relocs) {
ERROR_GLIBC("calloc");
return -1;
}
+
+ nr_reloc = 0;
for (i = 0; i < sec_num_entries(rsec); i++) {
reloc = &rsec->relocs[i];
@@ -1258,8 +1263,116 @@ struct section *elf_create_section(struct elf *elf, const char *name,
return sec;
}
+static int elf_alloc_reloc(struct elf *elf, struct section *rsec)
+{
+ struct reloc *old_relocs, *old_relocs_end, *new_relocs;
+ unsigned int nr_relocs_old = sec_num_entries(rsec);
+ unsigned int nr_relocs_new = nr_relocs_old + 1;
+ unsigned long nr_alloc;
+ struct symbol *sym;
+
+ if (!rsec->data) {
+ rsec->data = elf_newdata(elf_getscn(elf->elf, rsec->idx));
+ if (!rsec->data) {
+ ERROR_ELF("elf_newdata");
+ return -1;
+ }
+
+ rsec->data->d_align = 1;
+ rsec->data->d_type = ELF_T_RELA;
+ rsec->data->d_buf = NULL;
+ }
+
+ rsec->data->d_size = nr_relocs_new * elf_rela_size(elf);
+ rsec->sh.sh_size = rsec->data->d_size;
+
+ nr_alloc = MAX(64, ALIGN_UP_POW2(nr_relocs_new));
+ if (nr_alloc <= rsec->nr_alloc_relocs)
+ return 0;
+
+ if (rsec->data->d_buf && !rsec->nr_alloc_relocs) {
+ void *orig_buf = rsec->data->d_buf;
+
+ /*
+ * The original d_buf is owned by libelf so it can't be
+ * realloced.
+ */
+ rsec->data->d_buf = malloc(nr_alloc * elf_rela_size(elf));
+ if (!rsec->data->d_buf) {
+ ERROR_GLIBC("malloc");
+ return -1;
+ }
+ memcpy(rsec->data->d_buf, orig_buf,
+ nr_relocs_old * elf_rela_size(elf));
+ } else {
+ rsec->data->d_buf = realloc(rsec->data->d_buf,
+ nr_alloc * elf_rela_size(elf));
+ if (!rsec->data->d_buf) {
+ ERROR_GLIBC("realloc");
+ return -1;
+ }
+ }
+
+ rsec->nr_alloc_relocs = nr_alloc;
+
+ old_relocs = rsec->relocs;
+ new_relocs = calloc(nr_alloc, sizeof(struct reloc));
+ if (!new_relocs) {
+ ERROR_GLIBC("calloc");
+ return -1;
+ }
+
+ if (!old_relocs)
+ goto done;
+
+ /*
+ * The struct reloc's address has changed. Update all the symbols and
+ * relocs which reference it.
+ */
+
+ old_relocs_end = &old_relocs[nr_relocs_old];
+ for_each_sym(elf, sym) {
+ struct reloc *reloc;
+
+ reloc = sym->relocs;
+ if (!reloc)
+ continue;
+
+ if (reloc >= old_relocs && reloc < old_relocs_end)
+ sym->relocs = &new_relocs[reloc - old_relocs];
+
+ while (1) {
+ struct reloc *next_reloc = sym_next_reloc(reloc);
+
+ if (!next_reloc)
+ break;
+
+ if (next_reloc >= old_relocs && next_reloc < old_relocs_end)
+ set_sym_next_reloc(reloc, &new_relocs[next_reloc - old_relocs]);
+
+ reloc = next_reloc;
+ }
+ }
+
+ memcpy(new_relocs, old_relocs, nr_relocs_old * sizeof(struct reloc));
+
+ for (int i = 0; i < nr_relocs_old; i++) {
+ struct reloc *old = &old_relocs[i];
+ struct reloc *new = &new_relocs[i];
+ u32 key = reloc_hash(old);
+
+ elf_hash_del(reloc, &old->hash, key);
+ elf_hash_add(reloc, &new->hash, key);
+ }
+
+ free(old_relocs);
+done:
+ rsec->relocs = new_relocs;
+ return 0;
+}
+
struct section *elf_create_rela_section(struct elf *elf, struct section *sec,
- unsigned int reloc_nr)
+ unsigned int nr_relocs)
{
struct section *rsec;
char *rsec_name;
@@ -1272,34 +1385,63 @@ struct section *elf_create_rela_section(struct elf *elf, struct section *sec,
strcpy(rsec_name, ".rela");
strcat(rsec_name, sec->name);
- rsec = elf_create_section(elf, rsec_name, reloc_nr * elf_rela_size(elf),
+ rsec = elf_create_section(elf, rsec_name, nr_relocs * elf_rela_size(elf),
elf_rela_size(elf), SHT_RELA, elf_addr_size(elf),
SHF_INFO_LINK);
free(rsec_name);
if (!rsec)
return NULL;
- rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
- rsec->sh.sh_info = sec->idx;
-
- if (reloc_nr) {
+ if (nr_relocs) {
rsec->data->d_type = ELF_T_RELA;
- rsec->relocs = calloc(sec_num_entries(rsec), sizeof(struct reloc));
+
+ rsec->nr_alloc_relocs = nr_relocs;
+ rsec->relocs = calloc(nr_relocs, sizeof(struct reloc));
if (!rsec->relocs) {
ERROR_GLIBC("calloc");
return NULL;
}
}
+ rsec->sh.sh_link = find_section_by_name(elf, ".symtab")->idx;
+ rsec->sh.sh_info = sec->idx;
+
sec->rsec = rsec;
rsec->base = sec;
return rsec;
}
+struct reloc *elf_create_reloc(struct elf *elf, struct section *sec,
+ unsigned long offset,
+ struct symbol *sym, s64 addend,
+ unsigned int type)
+{
+ struct section *rsec = sec->rsec;
+
+ if (!rsec) {
+ rsec = elf_create_rela_section(elf, sec, 0);
+ if (!rsec)
+ return NULL;
+ }
+
+ if (find_reloc_by_dest(elf, sec, offset)) {
+ ERROR_FUNC(sec, offset, "duplicate reloc");
+ return NULL;
+ }
+
+ if (elf_alloc_reloc(elf, rsec))
+ return NULL;
+
+ mark_sec_changed(elf, rsec, true);
+
+ return elf_init_reloc(elf, rsec, sec_num_entries(rsec) - 1, offset, sym,
+ addend, type);
+}
+
struct section *elf_create_section_pair(struct elf *elf, const char *name,
size_t entsize, unsigned int nr,
- unsigned int reloc_nr)
+ unsigned int nr_relocs)
{
struct section *sec;
@@ -1308,7 +1450,7 @@ struct section *elf_create_section_pair(struct elf *elf, const char *name,
if (!sec)
return NULL;
- if (!elf_create_rela_section(elf, sec, reloc_nr))
+ if (!elf_create_rela_section(elf, sec, nr_relocs))
return NULL;
return sec;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 0d9aeefb6d124..999fd9369cf59 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -47,6 +47,7 @@ struct section {
int idx;
bool _changed, text, rodata, noinstr, init, truncate;
struct reloc *relocs;
+ unsigned long nr_alloc_relocs;
};
struct symbol {
@@ -140,6 +141,14 @@ void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str);
+struct reloc *elf_create_reloc(struct elf *elf, struct section *sec,
+ unsigned long offset, struct symbol *sym,
+ s64 addend, unsigned int type);
+
+struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
+ unsigned int reloc_idx, unsigned long offset,
+ struct symbol *sym, s64 addend, unsigned int type);
+
struct reloc *elf_init_reloc_text_sym(struct elf *elf, struct section *sec,
unsigned long offset,
unsigned int reloc_idx,
--
2.50.0Add interface to enable the creation of a new ELF file.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/builtin-check.c | 2 +-
tools/objtool/elf.c | 144 +++++++++++++++++++++++++++-
tools/objtool/include/objtool/elf.h | 5 +-
3 files changed, 147 insertions(+), 4 deletions(-)
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index e7a8f58f5630c..07983cdeded0f 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -329,5 +329,5 @@ int objtool_run(int argc, const char **argv)
if (!opts.dryrun && file->elf->changed && elf_write(file->elf))
return 1;
- return 0;
+ return elf_close(file->elf);
}
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 8d01fc3b4f679..6095baba8e9c5 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -16,6 +16,7 @@
#include <string.h>
#include <unistd.h>
#include <errno.h>
+#include <libgen.h>
#include <linux/interval_tree_generic.h>
#include <objtool/builtin.h>
#include <objtool/elf.h>
@@ -1067,6 +1068,12 @@ struct elf *elf_open_read(const char *name, int flags)
goto err;
}
+ elf->name = strdup(name);
+ if (!elf->name) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
if ((flags & O_ACCMODE) == O_RDONLY)
cmd = ELF_C_READ_MMAP;
else if ((flags & O_ACCMODE) == O_RDWR)
@@ -1104,6 +1111,137 @@ struct elf *elf_open_read(const char *name, int flags)
return NULL;
}
+struct elf *elf_create_file(GElf_Ehdr *ehdr, const char *name)
+{
+ struct section *null, *symtab, *strtab, *shstrtab;
+ char *dir, *base, *tmp_name;
+ struct symbol *sym;
+ struct elf *elf;
+
+ elf_version(EV_CURRENT);
+
+ elf = calloc(1, sizeof(*elf));
+ if (!elf) {
+ ERROR_GLIBC("calloc");
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&elf->sections);
+
+ dir = strdup(name);
+ if (!dir) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
+ dir = dirname(dir);
+
+ base = strdup(name);
+ if (!base) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
+ base = basename(base);
+
+ tmp_name = malloc(256);
+ if (!tmp_name) {
+ ERROR_GLIBC("malloc");
+ return NULL;
+ }
+
+ snprintf(tmp_name, 256, "%s/%s.XXXXXX", dir, base);
+
+ elf->fd = mkstemp(tmp_name);
+ if (elf->fd == -1) {
+ ERROR_GLIBC("can't create tmp file");
+ exit(1);
+ }
+
+ elf->tmp_name = tmp_name;
+
+ elf->name = strdup(name);
+ if (!elf->name) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
+ elf->elf = elf_begin(elf->fd, ELF_C_WRITE, NULL);
+ if (!elf->elf) {
+ ERROR_ELF("elf_begin");
+ return NULL;
+ }
+
+ if (!gelf_newehdr(elf->elf, ELFCLASS64)) {
+ ERROR_ELF("gelf_newehdr");
+ return NULL;
+ }
+
+ memcpy(&elf->ehdr, ehdr, sizeof(elf->ehdr));
+
+ if (!gelf_update_ehdr(elf->elf, &elf->ehdr)) {
+ ERROR_ELF("gelf_update_ehdr");
+ return NULL;
+ }
+
+ if (!elf_alloc_hash(section, 1000) ||
+ !elf_alloc_hash(section_name, 1000) ||
+ !elf_alloc_hash(symbol, 10000) ||
+ !elf_alloc_hash(symbol_name, 10000) ||
+ !elf_alloc_hash(reloc, 100000))
+ return NULL;
+
+ null = elf_create_section(elf, NULL, 0, 0, SHT_NULL, 0, 0);
+ shstrtab = elf_create_section(elf, NULL, 0, 0, SHT_STRTAB, 1, 0);
+ strtab = elf_create_section(elf, NULL, 0, 0, SHT_STRTAB, 1, 0);
+
+ if (!null || !shstrtab || !strtab)
+ return NULL;
+
+ null->name = "";
+ shstrtab->name = ".shstrtab";
+ strtab->name = ".strtab";
+
+ null->sh.sh_name = elf_add_string(elf, shstrtab, null->name);
+ shstrtab->sh.sh_name = elf_add_string(elf, shstrtab, shstrtab->name);
+ strtab->sh.sh_name = elf_add_string(elf, shstrtab, strtab->name);
+
+ if (null->sh.sh_name == -1 || shstrtab->sh.sh_name == -1 || strtab->sh.sh_name == -1)
+ return NULL;
+
+ elf_hash_add(section_name, &null->name_hash, str_hash(null->name));
+ elf_hash_add(section_name, &strtab->name_hash, str_hash(strtab->name));
+ elf_hash_add(section_name, &shstrtab->name_hash, str_hash(shstrtab->name));
+
+ if (elf_add_string(elf, strtab, "") == -1)
+ return NULL;
+
+ symtab = elf_create_section(elf, ".symtab", 0x18, 0x18, SHT_SYMTAB, 0x8, 0);
+ if (!symtab)
+ return NULL;
+
+ symtab->sh.sh_link = strtab->idx;
+ symtab->sh.sh_info = 1;
+
+ elf->ehdr.e_shstrndx = shstrtab->idx;
+ if (!gelf_update_ehdr(elf->elf, &elf->ehdr)) {
+ ERROR_ELF("gelf_update_ehdr");
+ return NULL;
+ }
+
+ sym = calloc(1, sizeof(*sym));
+ if (!sym) {
+ ERROR_GLIBC("calloc");
+ return NULL;
+ }
+
+ sym->name = "";
+ sym->sec = null;
+ elf_add_symbol(elf, sym);
+
+ return elf;
+}
+
unsigned int elf_add_string(struct elf *elf, struct section *strtab, const char *str)
{
unsigned int offset;
@@ -1568,7 +1706,7 @@ int elf_write(struct elf *elf)
return 0;
}
-void elf_close(struct elf *elf)
+int elf_close(struct elf *elf)
{
if (elf->elf)
elf_end(elf->elf);
@@ -1576,8 +1714,12 @@ void elf_close(struct elf *elf)
if (elf->fd > 0)
close(elf->fd);
+ if (elf->tmp_name && rename(elf->tmp_name, elf->name))
+ return -1;
+
/*
* NOTE: All remaining allocations are leaked on purpose. Objtool is
* about to exit anyway.
*/
+ return 0;
}
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 999fd9369cf59..9f135c262659e 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -94,7 +94,7 @@ struct elf {
GElf_Ehdr ehdr;
int fd;
bool changed;
- const char *name;
+ const char *name, *tmp_name;
unsigned int num_files;
struct list_head sections;
unsigned long num_relocs;
@@ -116,6 +116,7 @@ struct elf {
};
struct elf *elf_open_read(const char *name, int flags);
+struct elf *elf_create_file(GElf_Ehdr *ehdr, const char *name);
struct section *elf_create_section(struct elf *elf, const char *name,
size_t size, size_t entsize,
@@ -165,7 +166,7 @@ int elf_write_insn(struct elf *elf, struct section *sec, unsigned long offset,
unsigned int len, const char *insn);
int elf_write(struct elf *elf);
-void elf_close(struct elf *elf);
+int elf_close(struct elf *elf);
struct section *find_section_by_name(const struct elf *elf, const char *name);
struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
--
2.50.0... for reading annotation types.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/arch/loongarch/orc.c | 1 -
tools/objtool/arch/powerpc/decode.c | 1 -
tools/objtool/arch/x86/decode.c | 1 -
tools/objtool/arch/x86/orc.c | 1 -
tools/objtool/check.c | 5 +----
tools/objtool/include/objtool/elf.h | 13 +++++++++++++
tools/objtool/include/objtool/endianness.h | 9 ++++-----
tools/objtool/orc_dump.c | 1 -
tools/objtool/orc_gen.c | 1 -
tools/objtool/special.c | 1 -
10 files changed, 18 insertions(+), 16 deletions(-)
diff --git a/tools/objtool/arch/loongarch/orc.c b/tools/objtool/arch/loongarch/orc.c
index b58c5ff443c92..ffd3a3c858ae7 100644
--- a/tools/objtool/arch/loongarch/orc.c
+++ b/tools/objtool/arch/loongarch/orc.c
@@ -5,7 +5,6 @@
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
{
diff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c
index d4cb02120a6bd..3a9b748216edc 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -7,7 +7,6 @@
#include <objtool/arch.h>
#include <objtool/warn.h>
#include <objtool/builtin.h>
-#include <objtool/endianness.h>
int arch_ftrace_match(const char *name)
{
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 6bb46d9981533..b2c320f701f94 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -19,7 +19,6 @@
#include <objtool/elf.h>
#include <objtool/arch.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
#include <objtool/builtin.h>
#include <arch/elf.h>
diff --git a/tools/objtool/arch/x86/orc.c b/tools/objtool/arch/x86/orc.c
index 7176b9ec5b058..735e150ca6b73 100644
--- a/tools/objtool/arch/x86/orc.c
+++ b/tools/objtool/arch/x86/orc.c
@@ -5,7 +5,6 @@
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
{
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 6d21b83b9377a..969a61766f4a6 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -14,7 +14,6 @@
#include <objtool/check.h>
#include <objtool/special.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
#include <linux/objtool_types.h>
#include <linux/hashtable.h>
@@ -2273,9 +2272,7 @@ static int read_annotate(struct objtool_file *file,
}
for_each_reloc(sec->rsec, reloc) {
- type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * sec->sh.sh_entsize) + 4);
- type = bswap_if_needed(file->elf, type);
-
+ type = annotype(file->elf, sec, reloc);
offset = reloc->sym->offset + reloc_addend(reloc);
insn = find_insn(file, reloc->sym->sec, offset);
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 9f135c262659e..814cfc0bbf16b 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -13,10 +13,14 @@
#include <linux/hashtable.h>
#include <linux/rbtree.h>
#include <linux/jhash.h>
+
+#include <objtool/endianness.h>
#include <arch/elf.h>
#define SYM_NAME_LEN 512
+#define bswap_if_needed(elf, val) __bswap_if_needed(&elf->ehdr, val)
+
#ifdef LIBELF_USE_DEPRECATED
# define elf_getshdrnum elf_getshnum
# define elf_getshdrstrndx elf_getshstrndx
@@ -401,6 +405,15 @@ static inline void set_reloc_type(struct elf *elf, struct reloc *reloc, unsigned
mark_sec_changed(elf, reloc->sec, true);
}
+static inline unsigned int annotype(struct elf *elf, struct section *sec,
+ struct reloc *reloc)
+{
+ unsigned int type;
+
+ type = *(u32 *)(sec->data->d_buf + (reloc_idx(reloc) * 8) + 4);
+ return bswap_if_needed(elf, type);
+}
+
#define RELOC_JUMP_TABLE_BIT 1UL
/* Does reloc mark the beginning of a jump table? */
diff --git a/tools/objtool/include/objtool/endianness.h b/tools/objtool/include/objtool/endianness.h
index 4d2aa9b0fe2fd..aebcd23386685 100644
--- a/tools/objtool/include/objtool/endianness.h
+++ b/tools/objtool/include/objtool/endianness.h
@@ -4,7 +4,6 @@
#include <linux/kernel.h>
#include <endian.h>
-#include <objtool/elf.h>
/*
* Does a byte swap if target file endianness doesn't match the host, i.e. cross
@@ -12,16 +11,16 @@
* To be used for multi-byte values conversion, which are read from / about
* to be written to a target native endianness ELF file.
*/
-static inline bool need_bswap(struct elf *elf)
+static inline bool need_bswap(GElf_Ehdr *ehdr)
{
return (__BYTE_ORDER == __LITTLE_ENDIAN) ^
- (elf->ehdr.e_ident[EI_DATA] == ELFDATA2LSB);
+ (ehdr->e_ident[EI_DATA] == ELFDATA2LSB);
}
-#define bswap_if_needed(elf, val) \
+#define __bswap_if_needed(ehdr, val) \
({ \
__typeof__(val) __ret; \
- bool __need_bswap = need_bswap(elf); \
+ bool __need_bswap = need_bswap(ehdr); \
switch (sizeof(val)) { \
case 8: \
__ret = __need_bswap ? bswap_64(val) : (val); break; \
diff --git a/tools/objtool/orc_dump.c b/tools/objtool/orc_dump.c
index 1dd9fc18fe624..5a979f52425ab 100644
--- a/tools/objtool/orc_dump.c
+++ b/tools/objtool/orc_dump.c
@@ -8,7 +8,6 @@
#include <objtool/objtool.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
int orc_dump(const char *filename)
{
diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 9d380abc2ed35..1045e1380ffde 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -12,7 +12,6 @@
#include <objtool/check.h>
#include <objtool/orc.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
struct orc_list_entry {
struct list_head list;
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index fc2cf8dba1c03..e262af9171436 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -15,7 +15,6 @@
#include <objtool/builtin.h>
#include <objtool/special.h>
#include <objtool/warn.h>
-#include <objtool/endianness.h>
struct special_entry {
const char *sec;
--
2.50.0In preparation for using the objtool annotation macros in higher-level
objtool.h macros like UNWIND_HINT, move them to their own file.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/annotate.h | 109 +++++++++++++++++++++++++++++++++++++++
include/linux/objtool.h | 90 +-------------------------------
2 files changed, 110 insertions(+), 89 deletions(-)
create mode 100644 include/linux/annotate.h
diff --git a/include/linux/annotate.h b/include/linux/annotate.h
new file mode 100644
index 0000000000000..ccb445496331c
--- /dev/null
+++ b/include/linux/annotate.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_ANNOTATE_H
+#define _LINUX_ANNOTATE_H
+
+#include <linux/objtool_types.h>
+
+#ifdef CONFIG_OBJTOOL
+
+#ifndef __ASSEMBLY__
+
+#define __ASM_ANNOTATE(label, type) \
+ ".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \
+ ".long " __stringify(label) " - .\n\t" \
+ ".long " __stringify(type) "\n\t" \
+ ".popsection\n\t"
+
+#define ASM_ANNOTATE(type) \
+ "911:\n\t" \
+ __ASM_ANNOTATE(911b, type)
+
+#else /* __ASSEMBLY__ */
+
+.macro ANNOTATE type:req
+.Lhere_\@:
+ .pushsection .discard.annotate_insn,"M",@progbits,8
+ .long .Lhere_\@ - .
+ .long \type
+ .popsection
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#else /* !CONFIG_OBJTOOL */
+#ifndef __ASSEMBLY__
+#define __ASM_ANNOTATE(label, type) ""
+#define ASM_ANNOTATE(type)
+#else /* __ASSEMBLY__ */
+.macro ANNOTATE type:req
+.endm
+#endif /* __ASSEMBLY__ */
+#endif /* !CONFIG_OBJTOOL */
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Annotate away the various 'relocation to !ENDBR` complaints; knowing that
+ * these relocations will never be used for indirect calls.
+ */
+#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
+#define ANNOTATE_NOENDBR_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOENDBR))
+
+/*
+ * This should be used immediately before an indirect jump/call. It tells
+ * objtool the subsequent indirect jump/call is vouched safe for retpoline
+ * builds.
+ */
+#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
+/*
+ * See linux/instrumentation.h
+ */
+#define ANNOTATE_INSTR_BEGIN(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_BEGIN)
+#define ANNOTATE_INSTR_END(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_END)
+/*
+ * objtool annotation to ignore the alternatives and only consider the original
+ * instruction(s).
+ */
+#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
+/*
+ * This macro indicates that the following intra-function call is valid.
+ * Any non-annotated intra-function call will cause objtool to issue a warning.
+ */
+#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
+/*
+ * Use objtool to validate the entry requirement that all code paths do
+ * VALIDATE_UNRET_END before RET.
+ *
+ * NOTE: The macro must be used at the beginning of a global symbol, otherwise
+ * it will be ignored.
+ */
+#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)
+/*
+ * This should be used to refer to an instruction that is considered
+ * terminating, like a noreturn CALL or UD2 when we know they are not -- eg
+ * WARN using UD2.
+ */
+#define ANNOTATE_REACHABLE(label) __ASM_ANNOTATE(label, ANNOTYPE_REACHABLE)
+/*
+ * This should not be used; it annotates away CFI violations. There are a few
+ * valid use cases like kexec handover to the next kernel image, and there is
+ * no security concern there.
+ *
+ * There are also a few real issues annotated away, like EFI because we can't
+ * control the EFI code.
+ */
+#define ANNOTATE_NOCFI_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOCFI))
+
+#else /* __ASSEMBLY__ */
+#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
+#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
+/* ANNOTATE_INSTR_BEGIN ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
+/* ANNOTATE_INSTR_END ANNOTATE type=ANNOTYPE_INSTR_END */
+#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
+#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
+#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
+#define ANNOTATE_REACHABLE ANNOTATE type=ANNOTYPE_REACHABLE
+#define ANNOTATE_NOCFI_SYM ANNOTATE type=ANNOTYPE_NOCFI
+#endif /* __ASSEMBLY__ */
+
+#endif /* _LINUX_ANNOTATE_H */
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 46ebaa46e6c58..1973e9f14bf95 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -3,11 +3,10 @@
#define _LINUX_OBJTOOL_H
#include <linux/objtool_types.h>
+#include <linux/annotate.h>
#ifdef CONFIG_OBJTOOL
-#include <asm/asm.h>
-
#ifndef __ASSEMBLY__
#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
@@ -53,16 +52,6 @@
#define __ASM_BREF(label) label ## b
-#define __ASM_ANNOTATE(label, type) \
- ".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \
- ".long " __stringify(label) " - .\n\t" \
- ".long " __stringify(type) "\n\t" \
- ".popsection\n\t"
-
-#define ASM_ANNOTATE(type) \
- "911:\n\t" \
- __ASM_ANNOTATE(911b, type)
-
#else /* __ASSEMBLY__ */
/*
@@ -111,14 +100,6 @@
#endif
.endm
-.macro ANNOTATE type:req
-.Lhere_\@:
- .pushsection .discard.annotate_insn,"M",@progbits,8
- .long .Lhere_\@ - .
- .long \type
- .popsection
-.endm
-
#endif /* __ASSEMBLY__ */
#else /* !CONFIG_OBJTOOL */
@@ -128,84 +109,15 @@
#define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t"
#define STACK_FRAME_NON_STANDARD(func)
#define STACK_FRAME_NON_STANDARD_FP(func)
-#define __ASM_ANNOTATE(label, type) ""
-#define ASM_ANNOTATE(type)
#else
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.endm
.macro STACK_FRAME_NON_STANDARD func:req
.endm
-.macro ANNOTATE type:req
-.endm
#endif
#endif /* CONFIG_OBJTOOL */
-#ifndef __ASSEMBLY__
-/*
- * Annotate away the various 'relocation to !ENDBR` complaints; knowing that
- * these relocations will never be used for indirect calls.
- */
-#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
-#define ANNOTATE_NOENDBR_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOENDBR))
-
-/*
- * This should be used immediately before an indirect jump/call. It tells
- * objtool the subsequent indirect jump/call is vouched safe for retpoline
- * builds.
- */
-#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(ANNOTYPE_RETPOLINE_SAFE)
-/*
- * See linux/instrumentation.h
- */
-#define ANNOTATE_INSTR_BEGIN(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_BEGIN)
-#define ANNOTATE_INSTR_END(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_END)
-/*
- * objtool annotation to ignore the alternatives and only consider the original
- * instruction(s).
- */
-#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
-/*
- * This macro indicates that the following intra-function call is valid.
- * Any non-annotated intra-function call will cause objtool to issue a warning.
- */
-#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(ANNOTYPE_INTRA_FUNCTION_CALL)
-/*
- * Use objtool to validate the entry requirement that all code paths do
- * VALIDATE_UNRET_END before RET.
- *
- * NOTE: The macro must be used at the beginning of a global symbol, otherwise
- * it will be ignored.
- */
-#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(ANNOTYPE_UNRET_BEGIN)
-/*
- * This should be used to refer to an instruction that is considered
- * terminating, like a noreturn CALL or UD2 when we know they are not -- eg
- * WARN using UD2.
- */
-#define ANNOTATE_REACHABLE(label) __ASM_ANNOTATE(label, ANNOTYPE_REACHABLE)
-/*
- * This should not be used; it annotates away CFI violations. There are a few
- * valid use cases like kexec handover to the next kernel image, and there is
- * no security concern there.
- *
- * There are also a few real issues annotated away, like EFI because we can't
- * control the EFI code.
- */
-#define ANNOTATE_NOCFI_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOCFI))
-
-#else
-#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
-#define ANNOTATE_RETPOLINE_SAFE ANNOTATE type=ANNOTYPE_RETPOLINE_SAFE
-/* ANNOTATE_INSTR_BEGIN ANNOTATE type=ANNOTYPE_INSTR_BEGIN */
-/* ANNOTATE_INSTR_END ANNOTATE type=ANNOTYPE_INSTR_END */
-#define ANNOTATE_IGNORE_ALTERNATIVE ANNOTATE type=ANNOTYPE_IGNORE_ALTS
-#define ANNOTATE_INTRA_FUNCTION_CALL ANNOTATE type=ANNOTYPE_INTRA_FUNCTION_CALL
-#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
-#define ANNOTATE_REACHABLE ANNOTATE type=ANNOTYPE_REACHABLE
-#define ANNOTATE_NOCFI_SYM ANNOTATE type=ANNOTYPE_NOCFI
-#endif
-
#if defined(CONFIG_NOINSTR_VALIDATION) && \
(defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO))
#define VALIDATE_UNRET_BEGIN ANNOTATE_UNRET_BEGIN
--
2.50.0In preparation for the objtool klp diff subcommand, add an
ANNOTATE_DATA_SPECIAL macro which annotates special section entries so
that objtool can determine their size and location and extract them
when needed.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/annotate.h | 49 ++++++++++++++++++++++-------
include/linux/objtool_types.h | 2 ++
tools/include/linux/objtool_types.h | 2 ++
3 files changed, 41 insertions(+), 12 deletions(-)
diff --git a/include/linux/annotate.h b/include/linux/annotate.h
index ccb445496331c..7c10d34d198cf 100644
--- a/include/linux/annotate.h
+++ b/include/linux/annotate.h
@@ -8,34 +8,52 @@
#ifndef __ASSEMBLY__
-#define __ASM_ANNOTATE(label, type) \
- ".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \
+#define __ASM_ANNOTATE(section, label, type) \
+ ".pushsection " section ",\"M\", @progbits, 8\n\t" \
".long " __stringify(label) " - .\n\t" \
".long " __stringify(type) "\n\t" \
".popsection\n\t"
+#define ASM_ANNOTATE_LABEL(label, type) \
+ __ASM_ANNOTATE(".discard.annotate_insn", label, type)
+
#define ASM_ANNOTATE(type) \
"911:\n\t" \
- __ASM_ANNOTATE(911b, type)
+ ASM_ANNOTATE_LABEL(911b, type)
+
+#define ASM_ANNOTATE_DATA(type) \
+ "912:\n\t" \
+ __ASM_ANNOTATE(".discard.annotate_data", 912b, type)
#else /* __ASSEMBLY__ */
-.macro ANNOTATE type:req
+.macro __ANNOTATE section, type
.Lhere_\@:
- .pushsection .discard.annotate_insn,"M",@progbits,8
+ .pushsection \section, "M", @progbits, 8
.long .Lhere_\@ - .
.long \type
.popsection
.endm
+.macro ANNOTATE type
+ __ANNOTATE ".discard.annotate_insn", \type
+.endm
+
+.macro ANNOTATE_DATA type
+ __ANNOTATE ".discard.annotate_data", \type
+.endm
+
#endif /* __ASSEMBLY__ */
#else /* !CONFIG_OBJTOOL */
#ifndef __ASSEMBLY__
-#define __ASM_ANNOTATE(label, type) ""
+#define ASM_ANNOTATE_LABEL(label, type) ""
#define ASM_ANNOTATE(type)
+#define ASM_ANNOTATE_DATA(type)
#else /* __ASSEMBLY__ */
-.macro ANNOTATE type:req
+.macro ANNOTATE type
+.endm
+.macro ANNOTATE_DATA type
.endm
#endif /* __ASSEMBLY__ */
#endif /* !CONFIG_OBJTOOL */
@@ -47,7 +65,7 @@
* these relocations will never be used for indirect calls.
*/
#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
-#define ANNOTATE_NOENDBR_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOENDBR))
+#define ANNOTATE_NOENDBR_SYM(sym) asm(ASM_ANNOTATE_LABEL(sym, ANNOTYPE_NOENDBR))
/*
* This should be used immediately before an indirect jump/call. It tells
@@ -58,8 +76,8 @@
/*
* See linux/instrumentation.h
*/
-#define ANNOTATE_INSTR_BEGIN(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_BEGIN)
-#define ANNOTATE_INSTR_END(label) __ASM_ANNOTATE(label, ANNOTYPE_INSTR_END)
+#define ANNOTATE_INSTR_BEGIN(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_INSTR_BEGIN)
+#define ANNOTATE_INSTR_END(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_INSTR_END)
/*
* objtool annotation to ignore the alternatives and only consider the original
* instruction(s).
@@ -83,7 +101,7 @@
* terminating, like a noreturn CALL or UD2 when we know they are not -- eg
* WARN using UD2.
*/
-#define ANNOTATE_REACHABLE(label) __ASM_ANNOTATE(label, ANNOTYPE_REACHABLE)
+#define ANNOTATE_REACHABLE(label) ASM_ANNOTATE_LABEL(label, ANNOTYPE_REACHABLE)
/*
* This should not be used; it annotates away CFI violations. There are a few
* valid use cases like kexec handover to the next kernel image, and there is
@@ -92,7 +110,13 @@
* There are also a few real issues annotated away, like EFI because we can't
* control the EFI code.
*/
-#define ANNOTATE_NOCFI_SYM(sym) asm(__ASM_ANNOTATE(sym, ANNOTYPE_NOCFI))
+#define ANNOTATE_NOCFI_SYM(sym) asm(ASM_ANNOTATE_LABEL(sym, ANNOTYPE_NOCFI))
+
+/*
+ * Annotate a special section entry. This emables livepatch module generation
+ * to find and extract individual special section entries as needed.
+ */
+#define ANNOTATE_DATA_SPECIAL ASM_ANNOTATE_DATA(ANNOTYPE_DATA_SPECIAL)
#else /* __ASSEMBLY__ */
#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
@@ -104,6 +128,7 @@
#define ANNOTATE_UNRET_BEGIN ANNOTATE type=ANNOTYPE_UNRET_BEGIN
#define ANNOTATE_REACHABLE ANNOTATE type=ANNOTYPE_REACHABLE
#define ANNOTATE_NOCFI_SYM ANNOTATE type=ANNOTYPE_NOCFI
+#define ANNOTATE_DATA_SPECIAL ANNOTATE_DATA type=ANNOTYPE_DATA_SPECIAL
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_ANNOTATE_H */
diff --git a/include/linux/objtool_types.h b/include/linux/objtool_types.h
index aceac94632c8a..c6def4049b1ae 100644
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -67,4 +67,6 @@ struct unwind_hint {
#define ANNOTYPE_REACHABLE 8
#define ANNOTYPE_NOCFI 9
+#define ANNOTYPE_DATA_SPECIAL 1
+
#endif /* _LINUX_OBJTOOL_TYPES_H */
diff --git a/tools/include/linux/objtool_types.h b/tools/include/linux/objtool_types.h
index aceac94632c8a..c6def4049b1ae 100644
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -67,4 +67,6 @@ struct unwind_hint {
#define ANNOTYPE_REACHABLE 8
#define ANNOTYPE_NOCFI 9
+#define ANNOTYPE_DATA_SPECIAL 1
+
#endif /* _LINUX_OBJTOOL_TYPES_H */
--
2.50.0In preparation for the objtool klp diff subcommand, add annotations for
special section entries. This will enable objtool to determine the size
and location of the entries and to extract them when needed.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/include/asm/alternative.h | 4 ++++
arch/x86/include/asm/asm.h | 5 +++++
arch/x86/include/asm/bug.h | 1 +
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/include/asm/jump_label.h | 1 +
include/linux/objtool.h | 4 +++-
6 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 15bc07a5ebb39..b14c045679e16 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -198,6 +198,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define ALTINSTR_ENTRY(ft_flags) \
".pushsection .altinstructions,\"a\"\n" \
+ ANNOTATE_DATA_SPECIAL \
" .long 771b - .\n" /* label */ \
" .long 774f - .\n" /* new instruction */ \
" .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
@@ -207,6 +208,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
".pushsection .altinstr_replacement, \"ax\"\n" \
+ ANNOTATE_DATA_SPECIAL \
"# ALT: replacement\n" \
"774:\n\t" newinstr "\n775:\n" \
".popsection\n"
@@ -337,6 +339,7 @@ void nop_func(void);
* instruction. See apply_alternatives().
*/
.macro altinstr_entry orig alt ft_flags orig_len alt_len
+ ANNOTATE_DATA_SPECIAL
.long \orig - .
.long \alt - .
.4byte \ft_flags
@@ -365,6 +368,7 @@ void nop_func(void);
.popsection ; \
.pushsection .altinstr_replacement,"ax" ; \
743: \
+ ANNOTATE_DATA_SPECIAL ; \
newinst ; \
744: \
.popsection ;
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index d5c8d3afe1964..bd62bd87a841e 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -2,6 +2,8 @@
#ifndef _ASM_X86_ASM_H
#define _ASM_X86_ASM_H
+#include <linux/annotate.h>
+
#ifdef __ASSEMBLER__
# define __ASM_FORM(x, ...) x,## __VA_ARGS__
# define __ASM_FORM_RAW(x, ...) x,## __VA_ARGS__
@@ -132,6 +134,7 @@ static __always_inline __pure void *rip_rel_ptr(void *p)
# define _ASM_EXTABLE_TYPE(from, to, type) \
.pushsection "__ex_table","a" ; \
.balign 4 ; \
+ ANNOTATE_DATA_SPECIAL ; \
.long (from) - . ; \
.long (to) - . ; \
.long type ; \
@@ -179,6 +182,7 @@ static __always_inline __pure void *rip_rel_ptr(void *p)
# define _ASM_EXTABLE_TYPE(from, to, type) \
" .pushsection \"__ex_table\",\"a\"\n" \
" .balign 4\n" \
+ ANNOTATE_DATA_SPECIAL \
" .long (" #from ") - .\n" \
" .long (" #to ") - .\n" \
" .long " __stringify(type) " \n" \
@@ -187,6 +191,7 @@ static __always_inline __pure void *rip_rel_ptr(void *p)
# define _ASM_EXTABLE_TYPE_REG(from, to, type, reg) \
" .pushsection \"__ex_table\",\"a\"\n" \
" .balign 4\n" \
+ ANNOTATE_DATA_SPECIAL \
" .long (" #from ") - .\n" \
" .long (" #to ") - .\n" \
DEFINE_EXTABLE_TYPE_REG \
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index 70711183a020b..3910db28e2f5b 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -57,6 +57,7 @@
#define _BUG_FLAGS_ASM(ins, file, line, flags, size, extra) \
"1:\t" ins "\n" \
".pushsection __bug_table,\"aw\"\n" \
+ ANNOTATE_DATA_SPECIAL \
__BUG_ENTRY(file, line, flags) \
"\t.org 2b + " size "\n" \
".popsection\n" \
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 893cbca37fe99..fc5f32d4da6e1 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -101,6 +101,7 @@ static __always_inline bool _static_cpu_has(u16 bit)
asm goto(ALTERNATIVE_TERNARY("jmp 6f", %c[feature], "", "jmp %l[t_no]")
".pushsection .altinstr_aux,\"ax\"\n"
"6:\n"
+ ANNOTATE_DATA_SPECIAL
" testb %[bitnum], %a[cap_byte]\n"
" jnz %l[t_yes]\n"
" jmp %l[t_no]\n"
diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h
index 61dd1dee7812e..e0a6930a4029a 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -15,6 +15,7 @@
#define JUMP_TABLE_ENTRY(key, label) \
".pushsection __jump_table, \"aw\" \n\t" \
_ASM_ALIGN "\n\t" \
+ ANNOTATE_DATA_SPECIAL \
".long 1b - . \n\t" \
".long " label " - . \n\t" \
_ASM_PTR " " key " - . \n\t" \
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 1973e9f14bf95..4fea6a042b28f 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -9,9 +9,10 @@
#ifndef __ASSEMBLY__
-#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
"987: \n\t" \
".pushsection .discard.unwind_hints\n\t" \
+ ANNOTATE_DATA_SPECIAL \
/* struct unwind_hint */ \
".long 987b - .\n\t" \
".short " __stringify(sp_offset) "\n\t" \
@@ -78,6 +79,7 @@
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.Lhere_\@:
.pushsection .discard.unwind_hints
+ ANNOTATE_DATA_SPECIAL
/* struct unwind_hint */
.long .Lhere_\@ - .
.short \sp_offset
--
2.50.0The C implementation of STACK_FRAME_NON_STANDARD emits 8-byte entries,
whereas the asm version's entries are only 4 bytes.
Make them consistent by converting the asm version to 8-byte entries.
This is much easier than converting the C version to 4-bytes, which
would require awkwardly putting inline asm in a dummy function in order
to pass the 'func' pointer to the asm.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/objtool.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 4fea6a042b28f..b18ab53561c99 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -92,7 +92,7 @@
.macro STACK_FRAME_NON_STANDARD func:req
.pushsection .discard.func_stack_frame_non_standard, "aw"
- .long \func - .
+ .quad \func
.popsection
.endm
--
2.50.0In preparation for the objtool klp diff subcommand, add a command-line
option to generate a unique checksum for each function. This will
enable detection of functions which have changed between two versions of
an object file.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/Makefile | 38 +++--
tools/objtool/builtin-check.c | 11 +-
tools/objtool/check.c | 140 +++++++++++++++++-
tools/objtool/elf.c | 46 +++++-
tools/objtool/include/objtool/builtin.h | 5 +-
tools/objtool/include/objtool/check.h | 5 +-
tools/objtool/include/objtool/checksum.h | 42 ++++++
.../objtool/include/objtool/checksum_types.h | 25 ++++
tools/objtool/include/objtool/elf.h | 4 +-
9 files changed, 289 insertions(+), 27 deletions(-)
create mode 100644 tools/objtool/include/objtool/checksum.h
create mode 100644 tools/objtool/include/objtool/checksum_types.h
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index fc82d47f2b9a7..958761c05b7c3 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -2,6 +2,27 @@
include ../scripts/Makefile.include
include ../scripts/Makefile.arch
+ifeq ($(SRCARCH),x86)
+ BUILD_ORC := y
+ ARCH_HAS_KLP := y
+endif
+
+ifeq ($(SRCARCH),loongarch)
+ BUILD_ORC := y
+endif
+
+ifeq ($(ARCH_HAS_KLP),y)
+ HAVE_XXHASH = $(shell echo "int main() {}" | \
+ $(HOSTCC) -xc - -o /dev/null -lxxhash 2> /dev/null && echo y || echo n)
+ ifeq ($(HAVE_XXHASH),y)
+ LIBXXHASH_CFLAGS := $(shell $(HOSTPKG_CONFIG) libxxhash --cflags 2>/dev/null) \
+ -DBUILD_KLP
+ LIBXXHASH_LIBS := $(shell $(HOSTPKG_CONFIG) libxxhash --libs 2>/dev/null || echo -lxxhash)
+ endif
+endif
+
+export BUILD_ORC
+
ifeq ($(srctree),)
srctree := $(patsubst %/,%,$(dir $(CURDIR)))
srctree := $(patsubst %/,%,$(dir $(srctree)))
@@ -36,10 +57,10 @@ INCLUDES := -I$(srctree)/tools/include \
-I$(srctree)/tools/objtool/arch/$(SRCARCH)/include \
-I$(LIBSUBCMD_OUTPUT)/include
-OBJTOOL_CFLAGS := -std=gnu11 -fomit-frame-pointer -O2 -g \
- $(WARNINGS) $(INCLUDES) $(LIBELF_FLAGS) $(HOSTCFLAGS)
+OBJTOOL_CFLAGS := -std=gnu11 -fomit-frame-pointer -O2 -g $(WARNINGS) \
+ $(INCLUDES) $(LIBELF_FLAGS) $(LIBXXHASH_CFLAGS) $(HOSTCFLAGS)
-OBJTOOL_LDFLAGS := $(LIBSUBCMD) $(LIBELF_LIBS) $(HOSTLDFLAGS)
+OBJTOOL_LDFLAGS := $(LIBSUBCMD) $(LIBELF_LIBS) $(LIBXXHASH_LIBS) $(HOSTLDFLAGS)
# Allow old libelf to be used:
elfshdr := $(shell echo '$(pound)include <libelf.h>' | $(HOSTCC) $(OBJTOOL_CFLAGS) -x c -E - 2>/dev/null | grep elf_getshdr)
@@ -51,17 +72,6 @@ HOST_OVERRIDES := CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)"
AWK = awk
MKDIR = mkdir
-BUILD_ORC := n
-
-ifeq ($(SRCARCH),x86)
- BUILD_ORC := y
-endif
-
-ifeq ($(SRCARCH),loongarch)
- BUILD_ORC := y
-endif
-
-export BUILD_ORC
export srctree OUTPUT CFLAGS SRCARCH AWK
include $(srctree)/tools/build/Makefile.include
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 07983cdeded0f..101f05606a990 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -73,6 +73,7 @@ static int parse_hacks(const struct option *opt, const char *str, int unset)
static const struct option check_options[] = {
OPT_GROUP("Actions:"),
+ OPT_BOOLEAN(0, "checksum", &opts.checksum, "generate per-function checksums"),
OPT_BOOLEAN(0, "cfi", &opts.cfi, "annotate kernel control flow integrity (kCFI) function preambles"),
OPT_CALLBACK_OPTARG('h', "hacks", NULL, NULL, "jump_label,noinstr,skylake", "patch toolchain bugs/limitations", parse_hacks),
OPT_BOOLEAN('i', "ibt", &opts.ibt, "validate and annotate IBT"),
@@ -160,7 +161,15 @@ static bool opts_valid(void)
return false;
}
- if (opts.hack_jump_label ||
+#ifndef BUILD_KLP
+ if (opts.checksum) {
+ ERROR("--checksum not supported; install xxhash-devel and recompile");
+ return false;
+ }
+#endif
+
+ if (opts.checksum ||
+ opts.hack_jump_label ||
opts.hack_noinstr ||
opts.ibt ||
opts.mcount ||
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 969a61766f4a6..fec53407428e2 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -14,6 +14,7 @@
#include <objtool/check.h>
#include <objtool/special.h>
#include <objtool/warn.h>
+#include <objtool/checksum.h>
#include <linux/objtool_types.h>
#include <linux/hashtable.h>
@@ -971,6 +972,59 @@ static int create_direct_call_sections(struct objtool_file *file)
return 0;
}
+#ifdef BUILD_KLP
+static int create_sym_checksum_section(struct objtool_file *file)
+{
+ struct section *sec;
+ struct symbol *sym;
+ unsigned int idx = 0;
+ struct sym_checksum *checksum;
+ size_t entsize = sizeof(struct sym_checksum);
+
+ sec = find_section_by_name(file->elf, ".discard.sym_checksum");
+ if (sec) {
+ if (!opts.dryrun)
+ WARN("file already has .discard.sym_checksum section, skipping");
+
+ return 0;
+ }
+
+ for_each_sym(file->elf, sym)
+ if (sym->csum.checksum)
+ idx++;
+
+ if (!idx)
+ return 0;
+
+ sec = elf_create_section_pair(file->elf, ".discard.sym_checksum", entsize,
+ idx, idx);
+ if (!sec)
+ return -1;
+
+ idx = 0;
+ for_each_sym(file->elf, sym) {
+ if (!sym->csum.checksum)
+ continue;
+
+ if (!elf_init_reloc(file->elf, sec->rsec, idx, idx * entsize,
+ sym, 0, R_TEXT64))
+ return -1;
+
+ checksum = (struct sym_checksum *)sec->data->d_buf + idx;
+ checksum->addr = 0; /* reloc */
+ checksum->checksum = sym->csum.checksum;
+
+ mark_sec_changed(file->elf, sec, true);
+
+ idx++;
+ }
+
+ return 0;
+}
+#else
+static int create_sym_checksum_section(struct objtool_file *file) { return -EINVAL; }
+#endif
+
/*
* Warnings shouldn't be reported for ignored functions.
*/
@@ -1748,6 +1802,7 @@ static int handle_group_alt(struct objtool_file *file,
nop->type = INSN_NOP;
nop->sym = orig_insn->sym;
nop->alt_group = new_alt_group;
+ nop->fake = 1;
}
if (!special_alt->new_len) {
@@ -2527,6 +2582,14 @@ static void mark_holes(struct objtool_file *file)
}
}
+static bool validate_branch_enabled(void)
+{
+ return opts.stackval ||
+ opts.orc ||
+ opts.uaccess ||
+ opts.checksum;
+}
+
static int decode_sections(struct objtool_file *file)
{
mark_rodata(file);
@@ -2555,7 +2618,7 @@ static int decode_sections(struct objtool_file *file)
* Must be before add_jump_destinations(), which depends on 'func'
* being set for alternatives, to enable proper sibling call detection.
*/
- if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) {
+ if (validate_branch_enabled() || opts.noinstr) {
if (add_special_section_alts(file))
return -1;
}
@@ -3527,6 +3590,50 @@ static bool skip_alt_group(struct instruction *insn)
return alt_insn->type == INSN_CLAC || alt_insn->type == INSN_STAC;
}
+static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
+ struct instruction *insn)
+{
+ struct reloc *reloc = insn_reloc(file, insn);
+ unsigned long offset;
+ struct symbol *sym;
+
+ if (insn->fake)
+ return;
+
+ checksum_update(func, insn, insn->sec->data->d_buf + insn->offset, insn->len);
+
+ if (!reloc) {
+ struct symbol *call_dest = insn_call_dest(insn);
+
+ if (call_dest)
+ checksum_update(func, insn, call_dest->demangled_name,
+ strlen(call_dest->demangled_name));
+ return;
+ }
+
+ sym = reloc->sym;
+ offset = arch_insn_adjusted_addend(insn, reloc);
+
+ if (is_string_sec(sym->sec)) {
+ char *str;
+
+ str = sym->sec->data->d_buf + sym->offset + offset;
+ checksum_update(func, insn, str, strlen(str));
+ return;
+ }
+
+ if (is_sec_sym(sym)) {
+ sym = find_symbol_containing(reloc->sym->sec, offset);
+ if (!sym)
+ return;
+
+ offset -= sym->offset;
+ }
+
+ checksum_update(func, insn, sym->demangled_name, strlen(sym->demangled_name));
+ checksum_update(func, insn, &offset, sizeof(offset));
+}
+
/*
* Follow the branch starting at the given instruction, and recursively follow
* any other branches (jumps). Meanwhile, track the frame pointer state at
@@ -3547,6 +3654,9 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
while (1) {
next_insn = next_insn_to_validate(file, insn);
+ if (opts.checksum && func && insn->sec)
+ checksum_update_insn(file, func, insn);
+
if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
/* Ignore KCFI type preambles, which always fall through */
if (is_prefix_func(func))
@@ -3796,7 +3906,13 @@ static int validate_unwind_hint(struct objtool_file *file,
struct insn_state *state)
{
if (insn->hint && !insn->visited) {
- int ret = validate_branch(file, insn_func(insn), insn, *state);
+ struct symbol *func = insn_func(insn);
+ int ret;
+
+ if (opts.checksum)
+ checksum_init(func);
+
+ ret = validate_branch(file, func, insn, *state);
if (ret)
BT_INSN(insn, "<=== (hint)");
return ret;
@@ -4175,6 +4291,7 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
struct symbol *sym, struct insn_state *state)
{
struct instruction *insn;
+ struct symbol *func;
int ret;
if (!sym->len) {
@@ -4192,9 +4309,18 @@ static int validate_symbol(struct objtool_file *file, struct section *sec,
if (opts.uaccess)
state->uaccess = sym->uaccess_safe;
- ret = validate_branch(file, insn_func(insn), insn, *state);
+ func = insn_func(insn);
+
+ if (opts.checksum)
+ checksum_init(func);
+
+ ret = validate_branch(file, func, insn, *state);
if (ret)
BT_INSN(insn, "<=== (sym)");
+
+ if (opts.checksum)
+ checksum_finish(func);
+
return ret;
}
@@ -4712,7 +4838,7 @@ int check(struct objtool_file *file)
if (opts.retpoline)
warnings += validate_retpoline(file);
- if (opts.stackval || opts.orc || opts.uaccess) {
+ if (validate_branch_enabled()) {
int w = 0;
w += validate_functions(file);
@@ -4791,6 +4917,12 @@ int check(struct objtool_file *file)
if (opts.noabs)
warnings += check_abs_references(file);
+ if (opts.checksum) {
+ ret = create_sym_checksum_section(file);
+ if (ret)
+ goto out;
+ }
+
if (opts.orc && nr_insns) {
ret = orc_create(file);
if (ret)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 6095baba8e9c5..0119b3b4c5540 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -17,6 +17,7 @@
#include <unistd.h>
#include <errno.h>
#include <libgen.h>
+#include <ctype.h>
#include <linux/interval_tree_generic.h>
#include <objtool/builtin.h>
#include <objtool/elf.h>
@@ -412,7 +413,38 @@ static int read_sections(struct elf *elf)
return 0;
}
-static void elf_add_symbol(struct elf *elf, struct symbol *sym)
+static const char *demangle_name(struct symbol *sym)
+{
+ char *str;
+
+ if (!is_local_sym(sym))
+ return sym->name;
+
+ if (!is_func_sym(sym) && !is_object_sym(sym))
+ return sym->name;
+
+ if (!strstarts(sym->name, "__UNIQUE_ID_") && !strchr(sym->name, '.'))
+ return sym->name;
+
+ str = strdup(sym->name);
+ if (!str) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
+ for (int i = strlen(str) - 1; i >= 0; i--) {
+ char c = str[i];
+
+ if (!isdigit(c) && c != '.') {
+ str[i + 1] = '\0';
+ break;
+ }
+ };
+
+ return str;
+}
+
+static int elf_add_symbol(struct elf *elf, struct symbol *sym)
{
struct list_head *entry;
struct rb_node *pnode;
@@ -456,6 +488,12 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
if (is_func_sym(sym) && strstr(sym->name, ".cold"))
sym->cold = 1;
sym->pfunc = sym->cfunc = sym;
+
+ sym->demangled_name = demangle_name(sym);
+ if (!sym->demangled_name)
+ return -1;
+
+ return 0;
}
static int read_symbols(struct elf *elf)
@@ -529,7 +567,8 @@ static int read_symbols(struct elf *elf)
} else
sym->sec = find_section_by_index(elf, 0);
- elf_add_symbol(elf, sym);
+ if (elf_add_symbol(elf, sym))
+ return -1;
}
if (opts.stats) {
@@ -867,7 +906,8 @@ struct symbol *elf_create_symbol(struct elf *elf, const char *name,
mark_sec_changed(elf, symtab_shndx, true);
}
- elf_add_symbol(elf, sym);
+ if (elf_add_symbol(elf, sym))
+ return NULL;
return sym;
}
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index 7d559a2c13b7b..338bdab6b9ad8 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -9,12 +9,15 @@
struct opts {
/* actions: */
+ bool cfi;
+ bool checksum;
bool dump_orc;
bool hack_jump_label;
bool hack_noinstr;
bool hack_skylake;
bool ibt;
bool mcount;
+ bool noabs;
bool noinstr;
bool orc;
bool retpoline;
@@ -25,8 +28,6 @@ struct opts {
bool static_call;
bool uaccess;
int prefix;
- bool cfi;
- bool noabs;
/* options: */
bool backtrace;
diff --git a/tools/objtool/include/objtool/check.h b/tools/objtool/include/objtool/check.h
index 0f4e7ac929ef0..d73b0c3ae1ee3 100644
--- a/tools/objtool/include/objtool/check.h
+++ b/tools/objtool/include/objtool/check.h
@@ -65,8 +65,9 @@ struct instruction {
unret : 1,
visited : 4,
no_reloc : 1,
- hole : 1;
- /* 10 bit hole */
+ hole : 1,
+ fake : 1;
+ /* 9 bit hole */
struct alt_group *alt_group;
struct instruction *jump_dest;
diff --git a/tools/objtool/include/objtool/checksum.h b/tools/objtool/include/objtool/checksum.h
new file mode 100644
index 0000000000000..927ca74b5c39e
--- /dev/null
+++ b/tools/objtool/include/objtool/checksum.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_CHECKSUM_H
+#define _OBJTOOL_CHECKSUM_H
+
+#include <objtool/elf.h>
+
+#ifdef BUILD_KLP
+
+static inline void checksum_init(struct symbol *func)
+{
+ if (func && !func->csum.state) {
+ func->csum.state = XXH3_createState();
+ XXH3_64bits_reset(func->csum.state);
+ }
+}
+
+static inline void checksum_update(struct symbol *func,
+ struct instruction *insn,
+ const void *data, size_t size)
+{
+ XXH3_64bits_update(func->csum.state, data, size);
+}
+
+static inline void checksum_finish(struct symbol *func)
+{
+ if (func && func->csum.state) {
+ func->csum.checksum = XXH3_64bits_digest(func->csum.state);
+ func->csum.state = NULL;
+ }
+}
+
+#else /* !BUILD_KLP */
+
+static inline void checksum_init(struct symbol *func) {}
+static inline void checksum_update(struct symbol *func,
+ struct instruction *insn,
+ const void *data, size_t size) {}
+static inline void checksum_finish(struct symbol *func) {}
+
+#endif /* !BUILD_KLP */
+
+#endif /* _OBJTOOL_CHECKSUM_H */
diff --git a/tools/objtool/include/objtool/checksum_types.h b/tools/objtool/include/objtool/checksum_types.h
new file mode 100644
index 0000000000000..507efdd8ab5b9
--- /dev/null
+++ b/tools/objtool/include/objtool/checksum_types.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _OBJTOOL_CHECKSUM_TYPES_H
+#define _OBJTOOL_CHECKSUM_TYPES_H
+
+struct sym_checksum {
+ u64 addr;
+ u64 checksum;
+};
+
+#ifdef BUILD_KLP
+
+#include <xxhash.h>
+
+struct checksum {
+ XXH3_state_t *state;
+ XXH64_hash_t checksum;
+};
+
+#else /* !BUILD_KLP */
+
+struct checksum {};
+
+#endif /* !BUILD_KLP */
+
+#endif /* _OBJTOOL_CHECKSUM_TYPES_H */
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 814cfc0bbf16b..bc7d8a6167f8f 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -15,6 +15,7 @@
#include <linux/jhash.h>
#include <objtool/endianness.h>
+#include <objtool/checksum_types.h>
#include <arch/elf.h>
#define SYM_NAME_LEN 512
@@ -61,7 +62,7 @@ struct symbol {
struct elf_hash_node name_hash;
GElf_Sym sym;
struct section *sec;
- const char *name;
+ const char *name, *demangled_name;
unsigned int idx, len;
unsigned long offset;
unsigned long __subtree_last;
@@ -84,6 +85,7 @@ struct symbol {
struct list_head pv_target;
struct reloc *relocs;
struct section *group_sec;
+ struct checksum csum;
};
struct reloc {
--
2.50.0Add a --debug-checksum=<funcs> option to the check subcommand to print
the calculated checksum of each instruction in the given functions.
This is useful for determining where two versions of a function begin to
diverge.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/builtin-check.c | 6 ++++
tools/objtool/check.c | 42 ++++++++++++++++++++++++
tools/objtool/include/objtool/builtin.h | 1 +
tools/objtool/include/objtool/checksum.h | 1 +
tools/objtool/include/objtool/elf.h | 1 +
tools/objtool/include/objtool/warn.h | 19 +++++++++++
6 files changed, 70 insertions(+)
diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index 101f05606a990..b20b0077449b2 100644
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -94,6 +94,7 @@ static const struct option check_options[] = {
OPT_GROUP("Options:"),
OPT_BOOLEAN(0, "backtrace", &opts.backtrace, "unwind on error"),
OPT_BOOLEAN(0, "backup", &opts.backup, "create backup (.orig) file on warning/error"),
+ OPT_STRING(0, "debug-checksum", &opts.debug_checksum, "funcs", "enable checksum debug output"),
OPT_BOOLEAN(0, "dry-run", &opts.dryrun, "don't write modifications"),
OPT_BOOLEAN(0, "link", &opts.link, "object is a linked object"),
OPT_BOOLEAN(0, "module", &opts.module, "object is part of a kernel module"),
@@ -168,6 +169,11 @@ static bool opts_valid(void)
}
#endif
+ if (opts.debug_checksum && !opts.checksum) {
+ ERROR("--debug-checksum requires --checksum");
+ return false;
+ }
+
if (opts.checksum ||
opts.hack_jump_label ||
opts.hack_noinstr ||
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index fec53407428e2..5eb0c92aa9fe5 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3590,6 +3590,44 @@ static bool skip_alt_group(struct instruction *insn)
return alt_insn->type == INSN_CLAC || alt_insn->type == INSN_STAC;
}
+static int checksum_debug_init(struct objtool_file *file)
+{
+ char *dup, *s;
+
+ if (!opts.debug_checksum)
+ return 0;
+
+ dup = strdup(opts.debug_checksum);
+ if (!dup) {
+ ERROR_GLIBC("strdup");
+ return -1;
+ }
+
+ s = dup;
+ while (*s) {
+ struct symbol *func;
+ char *comma;
+
+ comma = strchr(s, ',');
+ if (comma)
+ *comma = '\0';
+
+ func = find_symbol_by_name(file->elf, s);
+ if (!func || !is_func_sym(func))
+ WARN("--debug-checksum: can't find '%s'", s);
+ else
+ func->debug_checksum = 1;
+
+ if (!comma)
+ break;
+
+ s = comma + 1;
+ }
+
+ free(dup);
+ return 0;
+}
+
static void checksum_update_insn(struct objtool_file *file, struct symbol *func,
struct instruction *insn)
{
@@ -4828,6 +4866,10 @@ int check(struct objtool_file *file)
cfi_hash_add(&init_cfi);
cfi_hash_add(&func_cfi);
+ ret = checksum_debug_init(file);
+ if (ret)
+ goto out;
+
ret = decode_sections(file);
if (ret)
goto out;
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index 338bdab6b9ad8..cee9fc0318777 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -32,6 +32,7 @@ struct opts {
/* options: */
bool backtrace;
bool backup;
+ const char *debug_checksum;
bool dryrun;
bool link;
bool mnop;
diff --git a/tools/objtool/include/objtool/checksum.h b/tools/objtool/include/objtool/checksum.h
index 927ca74b5c39e..7fe21608722ac 100644
--- a/tools/objtool/include/objtool/checksum.h
+++ b/tools/objtool/include/objtool/checksum.h
@@ -19,6 +19,7 @@ static inline void checksum_update(struct symbol *func,
const void *data, size_t size)
{
XXH3_64bits_update(func->csum.state, data, size);
+ dbg_checksum(func, insn, XXH3_64bits_digest(func->csum.state));
}
static inline void checksum_finish(struct symbol *func)
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index bc7d8a6167f8f..a1f1762f89c49 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -82,6 +82,7 @@ struct symbol {
u8 nocfi : 1;
u8 cold : 1;
u8 prefix : 1;
+ u8 debug_checksum : 1;
struct list_head pv_target;
struct reloc *relocs;
struct section *group_sec;
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index cb8fe846d9ddd..29173a1368d79 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -102,4 +102,23 @@ static inline char *offstr(struct section *sec, unsigned long offset)
#define ERROR_FUNC(sec, offset, format, ...) __WARN_FUNC(ERROR_STR, sec, offset, format, ##__VA_ARGS__)
#define ERROR_INSN(insn, format, ...) WARN_FUNC(insn->sec, insn->offset, format, ##__VA_ARGS__)
+
+#define __dbg(format, ...) \
+ fprintf(stderr, \
+ "DEBUG: %s%s" format "\n", \
+ objname ?: "", \
+ objname ? ": " : "", \
+ ##__VA_ARGS__)
+
+#define dbg_checksum(func, insn, checksum) \
+({ \
+ if (unlikely(insn->sym && insn->sym->pfunc && \
+ insn->sym->pfunc->debug_checksum)) { \
+ char *insn_off = offstr(insn->sec, insn->offset); \
+ __dbg("checksum: %s %s %016lx", \
+ func->name, insn_off, checksum); \
+ free(insn_off); \
+ } \
+})
+
#endif /* _WARN_H */
--
2.50.0Add a new klp diff subcommand which performs a binary diff between two
object files and extracts changed functions into a new object which can
then be linked into a livepatch module.
This builds on concepts from the longstanding out-of-tree kpatch [1]
project which began in 2012 and has been used for many years to generate
livepatch modules for production kernels. However, this is a complete
rewrite which incorporates hard-earned lessons from 12+ years of
maintaining kpatch.
Key improvements compared to kpatch-build:
- Integrated with objtool: Leverages objtool's existing control-flow
graph analysis to help detect changed functions.
- Works on vmlinux.o: Supports late-linked objects, making it
compatible with LTO, IBT, and similar.
- Simplified code base: ~3k fewer lines of code.
- Upstream: No more out-of-tree #ifdef hacks, far less cruft.
- Cleaner internals: Vastly simplified logic for symbol/section/reloc
inclusion and special section extraction.
- Robust __LINE__ macro handling: Avoids false positive binary diffs
caused by the __LINE__ macro by introducing a fix-patch-lines script
(coming in a later patch) which injects #line directives into the
source .patch to preserve the original line numbers at compile time.
Note the end result of this subcommand is not yet functionally complete.
Livepatch needs some ELF magic which linkers don't like:
- Two relocation sections (.rela*, .klp.rela*) for the same text
section.
- Use of SHN_LIVEPATCH to mark livepatch symbols.
Unfortunately linkers tend to mangle such things. To work around that,
klp diff generates a linker-compliant intermediate binary which encodes
the relevant KLP section/reloc/symbol metadata.
After module linking, a klp post-link step (coming soon) will clean up
the mess and convert the linked .ko into a fully compliant livepatch
module.
Note this subcommand requires the diffed binaries to have been compiled
with -ffunction-sections and -fdata-sections, and processed with
'objtool --checksum'. Those constraints will be handled by a klp-build
script introduced in a later patch.
Without '-ffunction-sections -fdata-sections', reliable object diffing
would be infeasible due to toolchain limitations:
- For intra-file+intra-section references, the compiler might
occasionally generated hard-coded instruction offsets instead of
relocations.
- Section-symbol-based references can be ambiguous:
- Overlapping or zero-length symbols create ambiguity as to which
symbol is being referenced.
- A reference to the end of a symbol (e.g., checking array bounds)
can be misinterpreted as a reference to the next symbol, or vice
versa.
A potential future alternative to '-ffunction-sections -fdata-sections'
would be to introduce a toolchain option that forces symbol-based
(non-section) relocations.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
MAINTAINERS | 2 +-
include/linux/livepatch.h | 25 +-
include/linux/livepatch_external.h | 76 +
kernel/livepatch/core.c | 4 +-
scripts/module.lds.S | 10 +-
tools/include/linux/livepatch_external.h | 76 +
tools/include/linux/string.h | 14 +
tools/objtool/Build | 4 +-
tools/objtool/Makefile | 3 +-
tools/objtool/arch/x86/decode.c | 40 +
tools/objtool/builtin-klp.c | 52 +
tools/objtool/check.c | 14 -
tools/objtool/elf.c | 21 +-
tools/objtool/include/objtool/arch.h | 1 +
tools/objtool/include/objtool/builtin.h | 2 +
tools/objtool/include/objtool/elf.h | 56 +-
tools/objtool/include/objtool/klp.h | 31 +
tools/objtool/include/objtool/objtool.h | 2 +
tools/objtool/include/objtool/util.h | 19 +
tools/objtool/klp-diff.c | 1646 ++++++++++++++++++++++
tools/objtool/objtool.c | 41 +-
tools/objtool/sync-check.sh | 1 +
tools/objtool/weak.c | 7 +
23 files changed, 2088 insertions(+), 59 deletions(-)
create mode 100644 include/linux/livepatch_external.h
create mode 100644 tools/include/linux/livepatch_external.h
create mode 100644 tools/objtool/builtin-klp.c
create mode 100644 tools/objtool/include/objtool/klp.h
create mode 100644 tools/objtool/include/objtool/util.h
create mode 100644 tools/objtool/klp-diff.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 4756cf7b88ae4..605390cdfb75e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14221,7 +14221,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching.g
F: Documentation/ABI/testing/sysfs-kernel-livepatch
F: Documentation/livepatch/
F: arch/powerpc/include/asm/livepatch.h
-F: include/linux/livepatch.h
+F: include/linux/livepatch*.h
F: kernel/livepatch/
F: kernel/module/livepatch.c
F: samples/livepatch/
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 51a258c24ff52..772919e8096aa 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -13,6 +13,7 @@
#include <linux/ftrace.h>
#include <linux/completion.h>
#include <linux/list.h>
+#include <linux/livepatch_external.h>
#include <linux/livepatch_sched.h>
#if IS_ENABLED(CONFIG_LIVEPATCH)
@@ -77,30 +78,6 @@ struct klp_func {
bool transition;
};
-struct klp_object;
-
-/**
- * struct klp_callbacks - pre/post live-(un)patch callback structure
- * @pre_patch: executed before code patching
- * @post_patch: executed after code patching
- * @pre_unpatch: executed before code unpatching
- * @post_unpatch: executed after code unpatching
- * @post_unpatch_enabled: flag indicating if post-unpatch callback
- * should run
- *
- * All callbacks are optional. Only the pre-patch callback, if provided,
- * will be unconditionally executed. If the parent klp_object fails to
- * patch for any reason, including a non-zero error status returned from
- * the pre-patch callback, no further callbacks will be executed.
- */
-struct klp_callbacks {
- int (*pre_patch)(struct klp_object *obj);
- void (*post_patch)(struct klp_object *obj);
- void (*pre_unpatch)(struct klp_object *obj);
- void (*post_unpatch)(struct klp_object *obj);
- bool post_unpatch_enabled;
-};
-
/**
* struct klp_object - kernel object structure for live patching
* @name: module name (or NULL for vmlinux)
diff --git a/include/linux/livepatch_external.h b/include/linux/livepatch_external.h
new file mode 100644
index 0000000000000..138af19b0f5cd
--- /dev/null
+++ b/include/linux/livepatch_external.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * External livepatch interfaces for patch creation tooling
+ */
+
+#ifndef _LINUX_LIVEPATCH_EXTERNAL_H_
+#define _LINUX_LIVEPATCH_EXTERNAL_H_
+
+#include <linux/types.h>
+
+#define KLP_RELOC_SEC_PREFIX ".klp.rela."
+#define KLP_SYM_PREFIX ".klp.sym."
+
+#define __KLP_PRE_PATCH_PREFIX __klp_pre_patch_callback_
+#define __KLP_POST_PATCH_PREFIX __klp_post_patch_callback_
+#define __KLP_PRE_UNPATCH_PREFIX __klp_pre_unpatch_callback_
+#define __KLP_POST_UNPATCH_PREFIX __klp_post_unpatch_callback_
+
+#define KLP_PRE_PATCH_PREFIX __stringify(__KLP_PRE_PATCH_PREFIX)
+#define KLP_POST_PATCH_PREFIX __stringify(__KLP_POST_PATCH_PREFIX)
+#define KLP_PRE_UNPATCH_PREFIX __stringify(__KLP_PRE_UNPATCH_PREFIX)
+#define KLP_POST_UNPATCH_PREFIX __stringify(__KLP_POST_UNPATCH_PREFIX)
+
+struct klp_object;
+
+typedef int (*klp_pre_patch_t)(struct klp_object *obj);
+typedef void (*klp_post_patch_t)(struct klp_object *obj);
+typedef void (*klp_pre_unpatch_t)(struct klp_object *obj);
+typedef void (*klp_post_unpatch_t)(struct klp_object *obj);
+
+/**
+ * struct klp_callbacks - pre/post live-(un)patch callback structure
+ * @pre_patch: executed before code patching
+ * @post_patch: executed after code patching
+ * @pre_unpatch: executed before code unpatching
+ * @post_unpatch: executed after code unpatching
+ * @post_unpatch_enabled: flag indicating if post-unpatch callback
+ * should run
+ *
+ * All callbacks are optional. Only the pre-patch callback, if provided,
+ * will be unconditionally executed. If the parent klp_object fails to
+ * patch for any reason, including a non-zero error status returned from
+ * the pre-patch callback, no further callbacks will be executed.
+ */
+struct klp_callbacks {
+ klp_pre_patch_t pre_patch;
+ klp_post_patch_t post_patch;
+ klp_pre_unpatch_t pre_unpatch;
+ klp_post_unpatch_t post_unpatch;
+ bool post_unpatch_enabled;
+};
+
+/*
+ * 'struct klp_{func,object}_ext' are compact "external" representations of
+ * 'struct klp_{func,object}'. They are used by objtool for livepatch
+ * generation. The structs are then read by the livepatch module and converted
+ * to the real structs before calling klp_enable_patch().
+ *
+ * TODO make these the official API for klp_enable_patch(). That should
+ * simplify livepatch's interface as well as its data structure lifetime
+ * management.
+ */
+struct klp_func_ext {
+ const char *old_name;
+ void *new_func;
+ unsigned long sympos;
+};
+
+struct klp_object_ext {
+ const char *name;
+ struct klp_func_ext *funcs;
+ struct klp_callbacks callbacks;
+ unsigned int nr_funcs;
+};
+
+#endif /* _LINUX_LIVEPATCH_EXTERNAL_H_ */
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 7e443c2cf7d48..0044a81250139 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -224,7 +224,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
/* Format: .klp.sym.sym_objname.sym_name,sympos */
cnt = sscanf(strtab + sym->st_name,
- ".klp.sym.%55[^.].%511[^,],%lu",
+ KLP_SYM_PREFIX "%55[^.].%511[^,],%lu",
sym_objname, sym_name, &sympos);
if (cnt != 3) {
pr_err("symbol %s has an incorrectly formatted name\n",
@@ -303,7 +303,7 @@ static int klp_write_section_relocs(struct module *pmod, Elf_Shdr *sechdrs,
* See comment in klp_resolve_symbols() for an explanation
* of the selected field width value.
*/
- cnt = sscanf(shstrtab + sec->sh_name, ".klp.rela.%55[^.]",
+ cnt = sscanf(shstrtab + sec->sh_name, KLP_RELOC_SEC_PREFIX "%55[^.]",
sec_objname);
if (cnt != 1) {
pr_err("section %s has an incorrectly formatted name\n",
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index 2632c6cb8ebe7..3037d5e5527c0 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -34,8 +34,16 @@ SECTIONS {
__patchable_function_entries : { *(__patchable_function_entries) }
+ __klp_funcs 0: ALIGN(8) { KEEP(*(__klp_funcs)) }
+
+ __klp_objects 0: ALIGN(8) {
+ __start_klp_objects = .;
+ KEEP(*(__klp_objects))
+ __stop_klp_objects = .;
+ }
+
#ifdef CONFIG_ARCH_USES_CFI_TRAPS
- __kcfi_traps : { KEEP(*(.kcfi_traps)) }
+ __kcfi_traps : { KEEP(*(.kcfi_traps)) }
#endif
.text : {
diff --git a/tools/include/linux/livepatch_external.h b/tools/include/linux/livepatch_external.h
new file mode 100644
index 0000000000000..138af19b0f5cd
--- /dev/null
+++ b/tools/include/linux/livepatch_external.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * External livepatch interfaces for patch creation tooling
+ */
+
+#ifndef _LINUX_LIVEPATCH_EXTERNAL_H_
+#define _LINUX_LIVEPATCH_EXTERNAL_H_
+
+#include <linux/types.h>
+
+#define KLP_RELOC_SEC_PREFIX ".klp.rela."
+#define KLP_SYM_PREFIX ".klp.sym."
+
+#define __KLP_PRE_PATCH_PREFIX __klp_pre_patch_callback_
+#define __KLP_POST_PATCH_PREFIX __klp_post_patch_callback_
+#define __KLP_PRE_UNPATCH_PREFIX __klp_pre_unpatch_callback_
+#define __KLP_POST_UNPATCH_PREFIX __klp_post_unpatch_callback_
+
+#define KLP_PRE_PATCH_PREFIX __stringify(__KLP_PRE_PATCH_PREFIX)
+#define KLP_POST_PATCH_PREFIX __stringify(__KLP_POST_PATCH_PREFIX)
+#define KLP_PRE_UNPATCH_PREFIX __stringify(__KLP_PRE_UNPATCH_PREFIX)
+#define KLP_POST_UNPATCH_PREFIX __stringify(__KLP_POST_UNPATCH_PREFIX)
+
+struct klp_object;
+
+typedef int (*klp_pre_patch_t)(struct klp_object *obj);
+typedef void (*klp_post_patch_t)(struct klp_object *obj);
+typedef void (*klp_pre_unpatch_t)(struct klp_object *obj);
+typedef void (*klp_post_unpatch_t)(struct klp_object *obj);
+
+/**
+ * struct klp_callbacks - pre/post live-(un)patch callback structure
+ * @pre_patch: executed before code patching
+ * @post_patch: executed after code patching
+ * @pre_unpatch: executed before code unpatching
+ * @post_unpatch: executed after code unpatching
+ * @post_unpatch_enabled: flag indicating if post-unpatch callback
+ * should run
+ *
+ * All callbacks are optional. Only the pre-patch callback, if provided,
+ * will be unconditionally executed. If the parent klp_object fails to
+ * patch for any reason, including a non-zero error status returned from
+ * the pre-patch callback, no further callbacks will be executed.
+ */
+struct klp_callbacks {
+ klp_pre_patch_t pre_patch;
+ klp_post_patch_t post_patch;
+ klp_pre_unpatch_t pre_unpatch;
+ klp_post_unpatch_t post_unpatch;
+ bool post_unpatch_enabled;
+};
+
+/*
+ * 'struct klp_{func,object}_ext' are compact "external" representations of
+ * 'struct klp_{func,object}'. They are used by objtool for livepatch
+ * generation. The structs are then read by the livepatch module and converted
+ * to the real structs before calling klp_enable_patch().
+ *
+ * TODO make these the official API for klp_enable_patch(). That should
+ * simplify livepatch's interface as well as its data structure lifetime
+ * management.
+ */
+struct klp_func_ext {
+ const char *old_name;
+ void *new_func;
+ unsigned long sympos;
+};
+
+struct klp_object_ext {
+ const char *name;
+ struct klp_func_ext *funcs;
+ struct klp_callbacks callbacks;
+ unsigned int nr_funcs;
+};
+
+#endif /* _LINUX_LIVEPATCH_EXTERNAL_H_ */
diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index 8499f509f03e7..51ad3cf4fa822 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -44,6 +44,20 @@ static inline bool strstarts(const char *str, const char *prefix)
return strncmp(str, prefix, strlen(prefix)) == 0;
}
+/*
+ * Checks if a string ends with another.
+ */
+static inline bool str_ends_with(const char *str, const char *substr)
+{
+ size_t len = strlen(str);
+ size_t sublen = strlen(substr);
+
+ if (sublen > len)
+ return false;
+
+ return !strcmp(str + len - sublen, substr);
+}
+
extern char * __must_check skip_spaces(const char *);
extern char *strim(char *);
diff --git a/tools/objtool/Build b/tools/objtool/Build
index a3cdf8af6635a..0b01657671d7f 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -8,8 +8,8 @@ objtool-y += builtin-check.o
objtool-y += elf.o
objtool-y += objtool.o
-objtool-$(BUILD_ORC) += orc_gen.o
-objtool-$(BUILD_ORC) += orc_dump.o
+objtool-$(BUILD_ORC) += orc_gen.o orc_dump.o
+objtool-$(BUILD_KLP) += builtin-klp.o klp-diff.o
objtool-y += libstring.o
objtool-y += libctype.o
diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
index 958761c05b7c3..48928c9bebef1 100644
--- a/tools/objtool/Makefile
+++ b/tools/objtool/Makefile
@@ -15,13 +15,14 @@ ifeq ($(ARCH_HAS_KLP),y)
HAVE_XXHASH = $(shell echo "int main() {}" | \
$(HOSTCC) -xc - -o /dev/null -lxxhash 2> /dev/null && echo y || echo n)
ifeq ($(HAVE_XXHASH),y)
+ BUILD_KLP := y
LIBXXHASH_CFLAGS := $(shell $(HOSTPKG_CONFIG) libxxhash --cflags 2>/dev/null) \
-DBUILD_KLP
LIBXXHASH_LIBS := $(shell $(HOSTPKG_CONFIG) libxxhash --libs 2>/dev/null || echo -lxxhash)
endif
endif
-export BUILD_ORC
+export BUILD_ORC BUILD_KLP
ifeq ($(srctree),)
srctree := $(patsubst %/,%,$(dir $(CURDIR)))
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index b2c320f701f94..5c72beeaa3a71 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -88,6 +88,46 @@ s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc)
return phys_to_virt(addend);
}
+static void scan_for_insn(struct section *sec, unsigned long offset,
+ unsigned long *insn_off, unsigned int *insn_len)
+{
+ unsigned long o = 0;
+ struct insn insn;
+
+ while (1) {
+
+ insn_decode(&insn, sec->data->d_buf + o, sec_size(sec) - o,
+ INSN_MODE_64);
+
+ if (o + insn.length > offset) {
+ *insn_off = o;
+ *insn_len = insn.length;
+ return;
+ }
+
+ o += insn.length;
+ }
+}
+
+u64 arch_adjusted_addend(struct reloc *reloc)
+{
+ unsigned int type = reloc_type(reloc);
+ s64 addend = reloc_addend(reloc);
+ unsigned long insn_off;
+ unsigned int insn_len;
+
+ if (type == R_X86_64_PLT32)
+ return addend + 4;
+
+ if (type != R_X86_64_PC32 || !is_text_sec(reloc->sec->base))
+ return addend;
+
+ scan_for_insn(reloc->sec->base, reloc_offset(reloc),
+ &insn_off, &insn_len);
+
+ return addend + insn_off + insn_len - reloc_offset(reloc);
+}
+
unsigned long arch_jump_destination(struct instruction *insn)
{
return insn->offset + insn->len + insn->immediate;
diff --git a/tools/objtool/builtin-klp.c b/tools/objtool/builtin-klp.c
new file mode 100644
index 0000000000000..9b13dd1182af1
--- /dev/null
+++ b/tools/objtool/builtin-klp.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <subcmd/parse-options.h>
+#include <string.h>
+#include <stdlib.h>
+#include <objtool/builtin.h>
+#include <objtool/objtool.h>
+#include <objtool/klp.h>
+
+struct subcmd {
+ const char *name;
+ const char *description;
+ int (*fn)(int, const char **);
+};
+
+static struct subcmd subcmds[] = {
+ { "diff", "Generate binary diff of two object files", cmd_klp_diff, },
+};
+
+static void cmd_klp_usage(void)
+{
+ fprintf(stderr, "usage: objtool klp <subcommand> [<options>]\n\n");
+ fprintf(stderr, "Subcommands:\n");
+
+ for (int i = 0; i < ARRAY_SIZE(subcmds); i++) {
+ struct subcmd *cmd = &subcmds[i];
+
+ fprintf(stderr, " %s\t%s\n", cmd->name, cmd->description);
+ }
+
+ exit(1);
+}
+
+int cmd_klp(int argc, const char **argv)
+{
+ argc--;
+ argv++;
+
+ if (!argc)
+ cmd_klp_usage();
+
+ if (argc) {
+ for (int i = 0; i < ARRAY_SIZE(subcmds); i++) {
+ struct subcmd *cmd = &subcmds[i];
+
+ if (!strcmp(cmd->name, argv[0]))
+ return cmd->fn(argc, argv);
+ }
+ }
+
+ cmd_klp_usage();
+ return 0;
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 5eb0c92aa9fe5..6eaae3c007486 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -185,20 +185,6 @@ static bool is_sibling_call(struct instruction *insn)
return (is_static_jump(insn) && insn_call_dest(insn));
}
-/*
- * Checks if a string ends with another.
- */
-static bool str_ends_with(const char *s, const char *sub)
-{
- const int slen = strlen(s);
- const int sublen = strlen(sub);
-
- if (sublen > slen)
- return 0;
-
- return !memcmp(s + slen - sublen, sub, sublen);
-}
-
/*
* Checks if a function is a Rust "noreturn" one.
*/
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 0119b3b4c5540..e1daae0630be9 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -288,6 +288,18 @@ struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
return NULL;
}
+struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *name)
+{
+ struct symbol *sym;
+
+ elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash(name)) {
+ if (!strcmp(sym->name, name) && !is_local_sym(sym))
+ return sym;
+ }
+
+ return NULL;
+}
+
struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec,
unsigned long offset, unsigned int len)
{
@@ -475,6 +487,8 @@ static int elf_add_symbol(struct elf *elf, struct symbol *sym)
else
entry = &sym->sec->symbol_list;
list_add(&sym->list, entry);
+
+ list_add_tail(&sym->global_list, &elf->symbols);
elf_hash_add(symbol, &sym->hash, sym->idx);
elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
@@ -531,6 +545,9 @@ static int read_symbols(struct elf *elf)
ERROR_GLIBC("calloc");
return -1;
}
+
+ INIT_LIST_HEAD(&elf->symbols);
+
for (i = 0; i < symbols_nr; i++) {
sym = &elf->symbol_data[i];
@@ -639,7 +656,7 @@ static int mark_group_syms(struct elf *elf)
return -1;
}
- list_for_each_entry(sec, &elf->sections, list) {
+ for_each_sec(elf, sec) {
if (sec->sh.sh_type == SHT_GROUP &&
sec->sh.sh_link == symtab->idx) {
sym = find_symbol_by_index(elf, sec->sh.sh_info);
@@ -1224,6 +1241,8 @@ struct elf *elf_create_file(GElf_Ehdr *ehdr, const char *name)
return NULL;
}
+ INIT_LIST_HEAD(&elf->symbols);
+
if (!elf_alloc_hash(section, 1000) ||
!elf_alloc_hash(section_name, 1000) ||
!elf_alloc_hash(symbol, 10000) ||
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index a4502947307a4..d89f8b5ec14e3 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -84,6 +84,7 @@ bool arch_callee_saved_reg(unsigned char reg);
unsigned long arch_jump_destination(struct instruction *insn);
s64 arch_insn_adjusted_addend(struct instruction *insn, struct reloc *reloc);
+u64 arch_adjusted_addend(struct reloc *reloc);
const char *arch_nop_insn(int len);
const char *arch_ret_insn(int len);
diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h
index cee9fc0318777..bb0b25eb08ba4 100644
--- a/tools/objtool/include/objtool/builtin.h
+++ b/tools/objtool/include/objtool/builtin.h
@@ -53,4 +53,6 @@ int objtool_run(int argc, const char **argv);
int make_backup(void);
+int cmd_klp(int argc, const char **argv);
+
#endif /* _BUILTIN_H */
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index a1f1762f89c49..e2cd817fca522 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -18,6 +18,7 @@
#include <objtool/checksum_types.h>
#include <arch/elf.h>
+#define SEC_NAME_LEN 1024
#define SYM_NAME_LEN 512
#define bswap_if_needed(elf, val) __bswap_if_needed(&elf->ehdr, val)
@@ -53,10 +54,12 @@ struct section {
bool _changed, text, rodata, noinstr, init, truncate;
struct reloc *relocs;
unsigned long nr_alloc_relocs;
+ struct section *twin;
};
struct symbol {
struct list_head list;
+ struct list_head global_list;
struct rb_node node;
struct elf_hash_node hash;
struct elf_hash_node name_hash;
@@ -83,10 +86,13 @@ struct symbol {
u8 cold : 1;
u8 prefix : 1;
u8 debug_checksum : 1;
+ u8 changed : 1;
+ u8 included : 1;
struct list_head pv_target;
struct reloc *relocs;
struct section *group_sec;
struct checksum csum;
+ struct symbol *twin, *clone;
};
struct reloc {
@@ -104,6 +110,7 @@ struct elf {
const char *name, *tmp_name;
unsigned int num_files;
struct list_head sections;
+ struct list_head symbols;
unsigned long num_relocs;
int symbol_bits;
@@ -179,6 +186,7 @@ struct section *find_section_by_name(const struct elf *elf, const char *name);
struct symbol *find_func_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_offset(struct section *sec, unsigned long offset);
struct symbol *find_symbol_by_name(const struct elf *elf, const char *name);
+struct symbol *find_global_symbol_by_name(const struct elf *elf, const char *name);
struct symbol *find_symbol_containing(const struct section *sec, unsigned long offset);
int find_symbol_hole_containing(const struct section *sec, unsigned long offset);
struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, unsigned long offset);
@@ -448,22 +456,48 @@ static inline void set_sym_next_reloc(struct reloc *reloc, struct reloc *next)
#define sec_for_each_sym(sec, sym) \
list_for_each_entry(sym, &sec->symbol_list, list)
+#define sec_prev_sym(sym) \
+ sym->sec && sym->list.prev != &sym->sec->symbol_list ? \
+ list_prev_entry(sym, list) : NULL
+
#define for_each_sym(elf, sym) \
- for (struct section *__sec, *__fake = (struct section *)1; \
- __fake; __fake = NULL) \
- for_each_sec(elf, __sec) \
- sec_for_each_sym(__sec, sym)
+ list_for_each_entry(sym, &elf->symbols, global_list)
+
+#define for_each_sym_continue(elf, sym) \
+ list_for_each_entry_continue(sym, &elf->symbols, global_list)
+
+#define rsec_next_reloc(rsec, reloc) \
+ reloc_idx(reloc) < sec_num_entries(rsec) - 1 ? reloc + 1 : NULL
#define for_each_reloc(rsec, reloc) \
- for (int __i = 0, __fake = 1; __fake; __fake = 0) \
- for (reloc = rsec->relocs; \
- __i < sec_num_entries(rsec); \
- __i++, reloc++)
+ for (reloc = rsec->relocs; reloc; reloc = rsec_next_reloc(rsec, reloc))
#define for_each_reloc_from(rsec, reloc) \
- for (int __i = reloc_idx(reloc); \
- __i < sec_num_entries(rsec); \
- __i++, reloc++)
+ for (; reloc; reloc = rsec_next_reloc(rsec, reloc))
+
+#define for_each_reloc_continue(rsec, reloc) \
+ for (reloc = rsec_next_reloc(rsec, reloc); reloc; \
+ reloc = rsec_next_reloc(rsec, reloc))
+
+#define sym_for_each_reloc(elf, sym, reloc) \
+ for (reloc = find_reloc_by_dest_range(elf, sym->sec, \
+ sym->offset, sym->len); \
+ reloc && reloc_offset(reloc) < sym->offset + sym->len; \
+ reloc = rsec_next_reloc(sym->sec->rsec, reloc))
+
+static inline struct symbol *get_func_prefix(struct symbol *func)
+{
+ struct symbol *prev;
+
+ if (!is_func_sym(func))
+ return NULL;
+
+ prev = sec_prev_sym(func);
+ if (prev && is_prefix_func(prev))
+ return prev;
+
+ return NULL;
+}
#define OFFSET_STRIDE_BITS 4
#define OFFSET_STRIDE (1UL << OFFSET_STRIDE_BITS)
diff --git a/tools/objtool/include/objtool/klp.h b/tools/objtool/include/objtool/klp.h
new file mode 100644
index 0000000000000..07928fac059b5
--- /dev/null
+++ b/tools/objtool/include/objtool/klp.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_KLP_H
+#define _OBJTOOL_KLP_H
+
+/*
+ * __klp_objects and __klp_funcs are created by klp diff and used by the patch
+ * module init code to build the klp_patch, klp_object and klp_func structs
+ * needed by the livepatch API.
+ */
+#define KLP_OBJECTS_SEC "__klp_objects"
+#define KLP_FUNCS_SEC "__klp_funcs"
+
+/*
+ * __klp_relocs is an intermediate section which are created by klp diff and
+ * converted into KLP symbols/relas by "objtool klp post-link". This is needed
+ * to work around the linker, which doesn't preserve SHN_LIVEPATCH or
+ * SHF_RELA_LIVEPATCH, nor does it support having two RELA sections for a
+ * single PROGBITS section.
+ */
+#define KLP_RELOCS_SEC "__klp_relocs"
+#define KLP_STRINGS_SEC ".rodata.klp.str1.1"
+
+struct klp_reloc {
+ void *offset;
+ void *sym;
+ u32 type;
+};
+
+int cmd_klp_diff(int argc, const char **argv);
+
+#endif /* _OBJTOOL_KLP_H */
diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h
index c0dc86a78ff65..7f70b41d1b8db 100644
--- a/tools/objtool/include/objtool/objtool.h
+++ b/tools/objtool/include/objtool/objtool.h
@@ -39,6 +39,8 @@ struct objtool_file {
struct pv_state *pv_ops;
};
+char *top_level_dir(const char *file);
+
struct objtool_file *objtool_open_read(const char *_objname);
int objtool_pv_add(struct objtool_file *file, int idx, struct symbol *func);
diff --git a/tools/objtool/include/objtool/util.h b/tools/objtool/include/objtool/util.h
new file mode 100644
index 0000000000000..a0180b312f732
--- /dev/null
+++ b/tools/objtool/include/objtool/util.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _UTIL_H
+#define _UTIL_H
+
+#include <objtool/warn.h>
+
+#define snprintf_check(str, size, format, args...) \
+({ \
+ int __ret = snprintf(str, size, format, args); \
+ if (__ret < 0) \
+ ERROR_GLIBC("snprintf"); \
+ else if (__ret >= size) \
+ ERROR("snprintf() failed for '" format "'", args); \
+ else \
+ __ret = 0; \
+ __ret; \
+})
+
+#endif /* _UTIL_H */
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
new file mode 100644
index 0000000000000..0d69b621a26cf
--- /dev/null
+++ b/tools/objtool/klp-diff.c
@@ -0,0 +1,1646 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#define _GNU_SOURCE /* memmem() */
+#include <subcmd/parse-options.h>
+#include <stdlib.h>
+#include <string.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <ctype.h>
+
+#include <objtool/objtool.h>
+#include <objtool/warn.h>
+#include <objtool/arch.h>
+#include <objtool/klp.h>
+#include <objtool/util.h>
+#include <arch/special.h>
+
+#include <linux/objtool_types.h>
+#include <linux/livepatch_external.h>
+#include <linux/stringify.h>
+#include <linux/string.h>
+#include <linux/jhash.h>
+
+#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+
+struct elfs {
+ struct elf *orig, *patched, *out;
+ const char *modname;
+};
+
+struct export {
+ struct hlist_node hash;
+ char *mod, *sym;
+};
+
+static const char * const klp_diff_usage[] = {
+ "objtool klp diff [<options>] <in1.o> <in2.o> <out.o>",
+ NULL,
+};
+
+static const struct option klp_diff_options[] = {
+ OPT_END(),
+};
+
+static DEFINE_HASHTABLE(exports, 15);
+
+static inline u32 str_hash(const char *str)
+{
+ return jhash(str, strlen(str), 0);
+}
+
+static int read_exports(void)
+{
+ const char *symvers = "Module.symvers";
+ char line[1024], *path = NULL;
+ unsigned int line_num = 1;
+ FILE *file;
+
+ file = fopen(symvers, "r");
+ if (!file) {
+ path = top_level_dir(symvers);
+ if (!path) {
+ ERROR("can't open '%s', \"objtool diff\" should be run from the kernel tree", symvers);
+ return -1;
+ }
+
+ file = fopen(path, "r");
+ if (!file) {
+ ERROR_GLIBC("fopen");
+ return -1;
+ }
+ }
+
+ while (fgets(line, 1024, file)) {
+ char *sym, *mod, *type;
+ struct export *export;
+
+ sym = strchr(line, '\t');
+ if (!sym) {
+ ERROR("malformed Module.symvers (sym) at line %d", line_num);
+ return -1;
+ }
+
+ *sym++ = '\0';
+
+ mod = strchr(sym, '\t');
+ if (!mod) {
+ ERROR("malformed Module.symvers (mod) at line %d", line_num);
+ return -1;
+ }
+
+ *mod++ = '\0';
+
+ type = strchr(mod, '\t');
+ if (!type) {
+ ERROR("malformed Module.symvers (type) at line %d", line_num);
+ return -1;
+ }
+
+ *type++ = '\0';
+
+ if (*sym == '\0' || *mod == '\0') {
+ ERROR("malformed Module.symvers at line %d", line_num);
+ return -1;
+ }
+
+ export = calloc(1, sizeof(*export));
+ if (!export) {
+ ERROR_GLIBC("calloc");
+ return -1;
+ }
+
+ export->mod = strdup(mod);
+ if (!export->mod) {
+ ERROR_GLIBC("strdup");
+ return -1;
+ }
+
+ export->sym = strdup(sym);
+ if (!export->sym) {
+ ERROR_GLIBC("strdup");
+ return -1;
+ }
+
+ hash_add(exports, &export->hash, str_hash(sym));
+ }
+
+ free(path);
+ fclose(file);
+
+ return 0;
+}
+
+static int read_sym_checksums(struct elf *elf)
+{
+ struct section *sec;
+
+ sec = find_section_by_name(elf, ".discard.sym_checksum");
+ if (!sec) {
+ ERROR("'%s' missing .discard.sym_checksum section, file not processed by 'objtool --checksum'?",
+ elf->name);
+ return -1;
+ }
+
+ if (!sec->rsec) {
+ ERROR("missing reloc section for .discard.sym_checksum");
+ return -1;
+ }
+
+ if (sec_size(sec) % sizeof(struct sym_checksum)) {
+ ERROR("struct sym_checksum size mismatch");
+ return -1;
+ }
+
+ for (int i = 0; i < sec_size(sec) / sizeof(struct sym_checksum); i++) {
+ struct sym_checksum *sym_checksum;
+ struct reloc *reloc;
+ struct symbol *sym;
+
+ sym_checksum = (struct sym_checksum *)sec->data->d_buf + i;
+
+ reloc = find_reloc_by_dest(elf, sec, i * sizeof(*sym_checksum));
+ if (!reloc) {
+ ERROR("can't find reloc for sym_checksum[%d]", i);
+ return -1;
+ }
+
+ sym = reloc->sym;
+
+ if (is_sec_sym(sym)) {
+ ERROR("not sure how to handle section %s", sym->name);
+ return -1;
+ }
+
+ if (is_func_sym(sym))
+ sym->csum.checksum = sym_checksum->checksum;
+ }
+
+ return 0;
+}
+
+static struct symbol *first_file_symbol(struct elf *elf)
+{
+ struct symbol *sym;
+
+ for_each_sym(elf, sym) {
+ if (is_file_sym(sym))
+ return sym;
+ }
+
+ return NULL;
+}
+
+static struct symbol *next_file_symbol(struct elf *elf, struct symbol *sym)
+{
+ for_each_sym_continue(elf, sym) {
+ if (is_file_sym(sym))
+ return sym;
+ }
+
+ return NULL;
+}
+
+/*
+ * Certain static local variables should never be correlated. They will be
+ * used in place rather than referencing the originals.
+ */
+static bool is_uncorrelated_static_local(struct symbol *sym)
+{
+ static const char * const vars[] = {
+ "__key.",
+ "__warned.",
+ "__already_done.",
+ "__func__.",
+ "_rs.",
+ "descriptor.",
+ "CSWTCH.",
+ };
+
+ if (!is_object_sym(sym) || !is_local_sym(sym))
+ return false;
+
+ if (!strcmp(sym->sec->name, ".data.once"))
+ return true;
+
+ for (int i = 0; i < ARRAY_SIZE(vars); i++) {
+ if (strstarts(sym->name, vars[i]))
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * Clang emits several useless .Ltmp_* code labels.
+ */
+static bool is_clang_tmp_label(struct symbol *sym)
+{
+ return sym->type == STT_NOTYPE &&
+ is_text_sec(sym->sec) &&
+ strstarts(sym->name, ".Ltmp") &&
+ isdigit(sym->name[5]);
+}
+
+static bool is_special_section(struct section *sec)
+{
+ static const char * const specials[] = {
+ ".altinstructions",
+ ".smp_locks",
+ "__bug_table",
+ "__ex_table",
+ "__jump_table",
+ "__mcount_loc",
+
+ /*
+ * Extract .static_call_sites here to inherit non-module
+ * preferential treatment. The later static call processing
+ * during klp module build will be skipped when it sees this
+ * section already exists.
+ */
+ ".static_call_sites",
+ };
+
+ static const char * const non_special_discards[] = {
+ ".discard.addressable",
+ ".discard.sym_checksum",
+ };
+
+ if (is_text_sec(sec))
+ return false;
+
+ for (int i = 0; i < ARRAY_SIZE(specials); i++) {
+ if (!strcmp(sec->name, specials[i]))
+ return true;
+ }
+
+ /* Most .discard data sections are special */
+ for (int i = 0; i < ARRAY_SIZE(non_special_discards); i++) {
+ if (!strcmp(sec->name, non_special_discards[i]))
+ return false;
+ }
+
+ return strstarts(sec->name, ".discard.");
+}
+
+/*
+ * These sections are referenced by special sections but aren't considered
+ * special sections themselves.
+ */
+static bool is_special_section_aux(struct section *sec)
+{
+ static const char * const specials_aux[] = {
+ ".altinstr_replacement",
+ ".altinstr_aux",
+ };
+
+ for (int i = 0; i < ARRAY_SIZE(specials_aux); i++) {
+ if (!strcmp(sec->name, specials_aux[i]))
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * These symbols should never be correlated, so their local patched versions
+ * are used instead of linking to the originals.
+ */
+static bool dont_correlate(struct symbol *sym)
+{
+ return is_file_sym(sym) ||
+ is_null_sym(sym) ||
+ is_sec_sym(sym) ||
+ is_prefix_func(sym) ||
+ is_uncorrelated_static_local(sym) ||
+ is_clang_tmp_label(sym) ||
+ is_string_sec(sym->sec) ||
+ is_special_section(sym->sec) ||
+ is_special_section_aux(sym->sec) ||
+ strstarts(sym->name, "__initcall__");
+}
+
+/*
+ * For each symbol in the original kernel, find its corresponding "twin" in the
+ * patched kernel.
+ */
+static int correlate_symbols(struct elfs *e)
+{
+ struct symbol *file1_sym, *file2_sym;
+ struct symbol *sym1, *sym2;
+
+ /* Correlate locals */
+ for (file1_sym = first_file_symbol(e->orig),
+ file2_sym = first_file_symbol(e->patched); ;
+ file1_sym = next_file_symbol(e->orig, file1_sym),
+ file2_sym = next_file_symbol(e->patched, file2_sym)) {
+
+ if (!file1_sym && file2_sym) {
+ ERROR("FILE symbol mismatch: NULL != %s", file2_sym->name);
+ return -1;
+ }
+
+ if (file1_sym && !file2_sym) {
+ ERROR("FILE symbol mismatch: %s != NULL", file1_sym->name);
+ return -1;
+ }
+
+ if (!file1_sym)
+ break;
+
+ if (strcmp(file1_sym->name, file2_sym->name)) {
+ ERROR("FILE symbol mismatch: %s != %s", file1_sym->name, file2_sym->name);
+ return -1;
+ }
+
+ file1_sym->twin = file2_sym;
+ file2_sym->twin = file1_sym;
+
+ sym1 = file1_sym;
+
+ for_each_sym_continue(e->orig, sym1) {
+ if (is_file_sym(sym1) || !is_local_sym(sym1))
+ break;
+
+ if (dont_correlate(sym1))
+ continue;
+
+ sym2 = file2_sym;
+ for_each_sym_continue(e->patched, sym2) {
+ if (is_file_sym(sym2) || !is_local_sym(sym2))
+ break;
+
+ if (sym2->twin || dont_correlate(sym2))
+ continue;
+
+ if (strcmp(sym1->demangled_name, sym2->demangled_name))
+ continue;
+
+ sym1->twin = sym2;
+ sym2->twin = sym1;
+ break;
+ }
+ }
+ }
+
+ /* Correlate globals */
+ for_each_sym(e->orig, sym1) {
+ if (sym1->bind == STB_LOCAL)
+ continue;
+
+ sym2 = find_global_symbol_by_name(e->patched, sym1->name);
+
+ if (sym2 && !sym2->twin && !strcmp(sym1->name, sym2->name)) {
+ sym1->twin = sym2;
+ sym2->twin = sym1;
+ }
+ }
+
+ for_each_sym(e->orig, sym1) {
+ if (sym1->twin || dont_correlate(sym1))
+ continue;
+ WARN("no correlation: %s", sym1->name);
+ }
+
+ return 0;
+}
+
+/* "sympos" is used by livepatch to disambiguate duplicate symbol names */
+static unsigned long find_sympos(struct elf *elf, struct symbol *sym)
+{
+ bool vmlinux = str_ends_with(objname, "vmlinux.o");
+ unsigned long sympos = 0, nr_matches = 0;
+ bool has_dup = false;
+ struct symbol *s;
+
+ if (sym->bind != STB_LOCAL)
+ return 0;
+
+ if (vmlinux && sym->type == STT_FUNC) {
+ /*
+ * HACK: Unfortunately, symbol ordering can differ between
+ * vmlinux.o and vmlinux due to the linker script emitting
+ * .text.unlikely* before .text*. Count .text.unlikely* first.
+ *
+ * TODO: Disambiguate symbols more reliably (checksums?)
+ */
+ for_each_sym(elf, s) {
+ if (strstarts(s->sec->name, ".text.unlikely") &&
+ !strcmp(s->name, sym->name)) {
+ nr_matches++;
+ if (s == sym)
+ sympos = nr_matches;
+ else
+ has_dup = true;
+ }
+ }
+ for_each_sym(elf, s) {
+ if (!strstarts(s->sec->name, ".text.unlikely") &&
+ !strcmp(s->name, sym->name)) {
+ nr_matches++;
+ if (s == sym)
+ sympos = nr_matches;
+ else
+ has_dup = true;
+ }
+ }
+ } else {
+ for_each_sym(elf, s) {
+ if (!strcmp(s->name, sym->name)) {
+ nr_matches++;
+ if (s == sym)
+ sympos = nr_matches;
+ else
+ has_dup = true;
+ }
+ }
+ }
+
+ if (!sympos) {
+ ERROR("can't find sympos for %s", sym->name);
+ return ULONG_MAX;
+ }
+
+ return has_dup ? sympos : 0;
+}
+
+static int clone_sym_relocs(struct elfs *e, struct symbol *patched_sym);
+
+static struct symbol *__clone_symbol(struct elf *elf, struct symbol *patched_sym,
+ bool data_too)
+{
+ struct section *out_sec = NULL;
+ unsigned long offset = 0;
+ struct symbol *out_sym;
+
+ if (data_too && !is_undef_sym(patched_sym)) {
+ struct section *patched_sec = patched_sym->sec;
+
+ out_sec = find_section_by_name(elf, patched_sec->name);
+ if (!out_sec) {
+ out_sec = elf_create_section(elf, patched_sec->name, 0,
+ patched_sec->sh.sh_entsize,
+ patched_sec->sh.sh_type,
+ patched_sec->sh.sh_addralign,
+ patched_sec->sh.sh_flags);
+ if (!out_sec)
+ return NULL;
+ }
+
+ if (is_string_sec(patched_sym->sec)) {
+ out_sym = elf_create_section_symbol(elf, out_sec);
+ if (!out_sym)
+ return NULL;
+
+ goto sym_created;
+ }
+
+ if (!is_sec_sym(patched_sym))
+ offset = sec_size(out_sec);
+
+ if (patched_sym->len || is_sec_sym(patched_sym)) {
+ void *data = NULL;
+ size_t size;
+
+ /* bss doesn't have data */
+ if (patched_sym->sec->data->d_buf)
+ data = patched_sym->sec->data->d_buf + patched_sym->offset;
+
+ if (is_sec_sym(patched_sym))
+ size = sec_size(patched_sym->sec);
+ else
+ size = patched_sym->len;
+
+ if (!elf_add_data(elf, out_sec, data, size))
+ return NULL;
+ }
+ }
+
+ out_sym = elf_create_symbol(elf, patched_sym->name, out_sec,
+ patched_sym->bind, patched_sym->type,
+ offset, patched_sym->len);
+ if (!out_sym)
+ return NULL;
+
+sym_created:
+ patched_sym->clone = out_sym;
+ out_sym->clone = patched_sym;
+
+ return out_sym;
+}
+
+/*
+ * Copy a symbol to the output object, optionally including its data and
+ * relocations.
+ */
+static struct symbol *clone_symbol(struct elfs *e, struct symbol *patched_sym,
+ bool data_too)
+{
+ struct symbol *pfx;
+
+ if (patched_sym->clone)
+ return patched_sym->clone;
+
+ /* Make sure the prefix gets cloned first */
+ if (is_func_sym(patched_sym) && data_too) {
+ pfx = get_func_prefix(patched_sym);
+ if (pfx)
+ clone_symbol(e, pfx, true);
+ }
+
+ if (!__clone_symbol(e->out, patched_sym, data_too))
+ return NULL;
+
+ if (data_too && clone_sym_relocs(e, patched_sym))
+ return NULL;
+
+ return patched_sym->clone;
+}
+
+static void mark_included_function(struct symbol *func)
+{
+ struct symbol *pfx;
+
+ func->included = 1;
+
+ /* Include prefix function */
+ pfx = get_func_prefix(func);
+ if (pfx)
+ pfx->included = 1;
+
+ /* Make sure .cold parent+child always stay together */
+ if (func->cfunc && func->cfunc != func)
+ func->cfunc->included = 1;
+ if (func->pfunc && func->pfunc != func)
+ func->pfunc->included = 1;
+}
+
+/*
+ * Copy all changed functions (and their dependencies) from the patched object
+ * to the output object.
+ */
+static int mark_changed_functions(struct elfs *e)
+{
+ struct symbol *sym_orig, *patched_sym;
+ bool changed = false;
+
+ /* Find changed functions */
+ for_each_sym(e->orig, sym_orig) {
+ if (!is_func_sym(sym_orig) || is_prefix_func(sym_orig))
+ continue;
+
+ patched_sym = sym_orig->twin;
+ if (!patched_sym)
+ continue;
+
+ if (sym_orig->csum.checksum != patched_sym->csum.checksum) {
+ patched_sym->changed = 1;
+ mark_included_function(patched_sym);
+ changed = true;
+ }
+ }
+
+ /* Find added functions and print them */
+ for_each_sym(e->patched, patched_sym) {
+ if (!is_func_sym(patched_sym) || is_prefix_func(patched_sym))
+ continue;
+
+ if (!patched_sym->twin) {
+ printf("%s: new function: %s\n", objname, patched_sym->name);
+ mark_included_function(patched_sym);
+ changed = true;
+ }
+ }
+
+ /* Print changed functions */
+ for_each_sym(e->patched, patched_sym) {
+ if (patched_sym->changed)
+ printf("%s: changed function: %s\n", objname, patched_sym->name);
+ }
+
+ return !changed ? -1 : 0;
+}
+
+static int clone_included_functions(struct elfs *e)
+{
+ struct symbol *patched_sym;
+
+ for_each_sym(e->patched, patched_sym) {
+ if (patched_sym->included) {
+ if (!clone_symbol(e, patched_sym, true))
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Determine whether a relocation should reference the section rather than the
+ * underlying symbol.
+ */
+static bool section_reference_needed(struct section *sec)
+{
+ /*
+ * String symbols are zero-length and uncorrelated. It's easier to
+ * deal with them as section symbols.
+ */
+ if (is_string_sec(sec))
+ return true;
+
+ /*
+ * .rodata has mostly anonymous data so there's no way to determine the
+ * length of a needed reference. just copy the whole section if needed.
+ */
+ if (strstarts(sec->name, ".rodata"))
+ return true;
+
+ /* UBSAN anonymous data */
+ if (strstarts(sec->name, ".data..Lubsan") || /* GCC */
+ strstarts(sec->name, ".data..L__unnamed_")) /* Clang */
+ return true;
+
+ return false;
+}
+
+static bool is_reloc_allowed(struct reloc *reloc)
+{
+ return section_reference_needed(reloc->sym->sec) == is_sec_sym(reloc->sym);
+}
+
+static struct export *find_export(struct symbol *sym)
+{
+ struct export *export;
+
+ hash_for_each_possible(exports, export, hash, str_hash(sym->name)) {
+ if (!strcmp(export->sym, sym->name))
+ return export;
+ }
+
+ return NULL;
+}
+
+static const char *__find_modname(struct elfs *e)
+{
+ struct section *sec;
+ char *name;
+
+ sec = find_section_by_name(e->orig, ".modinfo");
+ if (!sec) {
+ ERROR("missing .modinfo section");
+ return NULL;
+ }
+
+ name = memmem(sec->data->d_buf, sec_size(sec), "\0name=", 6);
+ if (name)
+ return name + 6;
+
+ name = strdup(e->orig->name);
+ if (!name) {
+ ERROR_GLIBC("strdup");
+ return NULL;
+ }
+
+ for (char *c = name; *c; c++) {
+ if (*c == '/')
+ name = c + 1;
+ else if (*c == '-')
+ *c = '_';
+ else if (*c == '.') {
+ *c = '\0';
+ break;
+ }
+ }
+
+ return name;
+}
+
+/* Get the object's module name as defined by the kernel (and klp_object) */
+static const char *find_modname(struct elfs *e)
+{
+ const char *modname;
+
+ if (e->modname)
+ return e->modname;
+
+ modname = __find_modname(e);
+ e->modname = modname;
+ return modname;
+}
+
+/*
+ * Copying a function from its native compiled environment to a kernel module
+ * removes its natural access to local functions/variables and unexported
+ * globals. References to such symbols need to be converted to KLP relocs so
+ * the kernel arch relocation code knows to apply them and where to find the
+ * symbols. Particularly, duplicate static symbols need to be disambiguated.
+ */
+static bool klp_reloc_needed(struct reloc *patched_reloc)
+{
+ struct symbol *patched_sym = patched_reloc->sym;
+ struct export *export;
+
+ /* no external symbol to reference */
+ if (dont_correlate(patched_sym))
+ return false;
+
+ /* For included functions, a regular reloc will do. */
+ if (patched_sym->included)
+ return false;
+
+ /*
+ * If exported by a module, it has to be a klp reloc. Thanks to the
+ * clusterfunk that is late module patching, the patch module is
+ * allowed to be loaded before any modules it depends on.
+ *
+ * If exported by vmlinux, a normal reloc will do.
+ */
+ export = find_export(patched_sym);
+ if (export)
+ return strcmp(export->mod, "vmlinux");
+
+ if (!patched_sym->twin) {
+ /*
+ * Presumably the symbol and its reference were added by the
+ * patch. The symbol could be defined in this .o or in another
+ * .o in the patch module.
+ *
+ * This check needs to be *after* the export check due to the
+ * possibility of the patch adding a new UNDEF reference to an
+ * exported symbol.
+ */
+ return false;
+ }
+
+ /* Unexported symbol which lives in the original vmlinux or module. */
+ return true;
+}
+
+static int convert_reloc_sym_to_secsym(struct elf *elf, struct reloc *reloc)
+{
+ struct symbol *sym = reloc->sym;
+ struct section *sec = sym->sec;
+
+ if (!sec->sym && !elf_create_section_symbol(elf, sec))
+ return -1;
+
+ reloc->sym = sec->sym;
+ set_reloc_sym(elf, reloc, sym->idx);
+ set_reloc_addend(elf, reloc, sym->offset + reloc_addend(reloc));
+ return 0;
+}
+
+static int convert_reloc_secsym_to_sym(struct elf *elf, struct reloc *reloc)
+{
+ struct symbol *sym = reloc->sym;
+ struct section *sec = sym->sec;
+
+ /* If the symbol has a dedicated section, it's easy to find */
+ sym = find_symbol_by_offset(sec, 0);
+ if (sym && sym->len == sec_size(sec))
+ goto found_sym;
+
+ /* No dedicated section; find the symbol manually */
+ sym = find_symbol_containing(sec, arch_adjusted_addend(reloc));
+ if (!sym) {
+ /*
+ * This can happen for special section references to weak code
+ * whose symbol has been stripped by the linker.
+ */
+ return -1;
+ }
+
+found_sym:
+ reloc->sym = sym;
+ set_reloc_sym(elf, reloc, sym->idx);
+ set_reloc_addend(elf, reloc, reloc_addend(reloc) - sym->offset);
+ return 0;
+}
+
+/*
+ * Convert a relocation symbol reference to the needed format: either a section
+ * symbol or the underlying symbol itself.
+ */
+static int convert_reloc_sym(struct elf *elf, struct reloc *reloc)
+{
+ if (is_reloc_allowed(reloc))
+ return 0;
+
+ if (section_reference_needed(reloc->sym->sec))
+ return convert_reloc_sym_to_secsym(elf, reloc);
+ else
+ return convert_reloc_secsym_to_sym(elf, reloc);
+}
+
+/*
+ * Convert a regular relocation to a klp relocation (sort of).
+ */
+static int clone_reloc_klp(struct elfs *e, struct reloc *patched_reloc,
+ struct section *sec, unsigned long offset,
+ struct export *export)
+{
+ struct symbol *patched_sym = patched_reloc->sym;
+ s64 addend = reloc_addend(patched_reloc);
+ const char *sym_modname, *sym_orig_name;
+ static struct section *klp_relocs;
+ struct symbol *sym, *klp_sym;
+ unsigned long klp_reloc_off;
+ char sym_name[SYM_NAME_LEN];
+ struct klp_reloc klp_reloc;
+ unsigned long sympos;
+
+ if (!patched_sym->twin) {
+ ERROR("unexpected klp reloc for new symbol %s", patched_sym->name);
+ return -1;
+ }
+
+ /*
+ * Keep the original reloc intact for now to avoid breaking objtool run
+ * which relies on proper relocations for many of its features. This
+ * will be disabled later by "objtool klp post-link".
+ *
+ * Convert it to UNDEF (and WEAK to avoid modpost warnings).
+ */
+
+ sym = patched_sym->clone;
+ if (!sym) {
+ /* STB_WEAK: avoid modpost undefined symbol warnings */
+ sym = elf_create_symbol(e->out, patched_sym->name, NULL,
+ STB_WEAK, patched_sym->type, 0, 0);
+ if (!sym)
+ return -1;
+
+ patched_sym->clone = sym;
+ sym->clone = patched_sym;
+ }
+
+ if (!elf_create_reloc(e->out, sec, offset, sym, addend, reloc_type(patched_reloc)))
+ return -1;
+
+ /*
+ * Create the KLP symbol.
+ */
+
+ if (export) {
+ sym_modname = export->mod;
+ sym_orig_name = export->sym;
+ sympos = 0;
+ } else {
+ sym_modname = find_modname(e);
+ if (!sym_modname)
+ return -1;
+
+ sym_orig_name = patched_sym->twin->name;
+ sympos = find_sympos(e->orig, patched_sym->twin);
+ if (sympos == ULONG_MAX)
+ return -1;
+ }
+
+ /* symbol format: .klp.sym.modname.sym_name,sympos */
+ if (snprintf_check(sym_name, SYM_NAME_LEN, KLP_SYM_PREFIX "%s.%s,%ld",
+ sym_modname, sym_orig_name, sympos))
+ return -1;
+
+ klp_sym = find_symbol_by_name(e->out, sym_name);
+ if (!klp_sym) {
+ /* STB_WEAK: avoid modpost undefined symbol warnings */
+ klp_sym = elf_create_symbol(e->out, sym_name, NULL,
+ STB_WEAK, patched_sym->type, 0, 0);
+ if (!klp_sym)
+ return -1;
+ }
+
+ /*
+ * Create the __klp_relocs entry. This will be converted to an actual
+ * KLP rela by "objtool klp post-link".
+ *
+ * This intermediate step is necessary to prevent corruption by the
+ * linker, which doesn't know how to properly handle two rela sections
+ * applying to the same base section.
+ */
+
+ if (!klp_relocs) {
+ klp_relocs = elf_create_section(e->out, KLP_RELOCS_SEC, 0,
+ 0, SHT_PROGBITS, 8, SHF_ALLOC);
+ if (!klp_relocs)
+ return -1;
+ }
+
+ klp_reloc_off = sec_size(klp_relocs);
+ memset(&klp_reloc, 0, sizeof(klp_reloc));
+
+ klp_reloc.type = reloc_type(patched_reloc);
+ if (!elf_add_data(e->out, klp_relocs, &klp_reloc, sizeof(klp_reloc)))
+ return -1;
+
+ /* klp_reloc.offset */
+ if (!sec->sym && !elf_create_section_symbol(e->out, sec))
+ return -1;
+
+ if (!elf_create_reloc(e->out, klp_relocs,
+ klp_reloc_off + offsetof(struct klp_reloc, offset),
+ sec->sym, offset, R_ABS64))
+ return -1;
+
+ /* klp_reloc.sym */
+ if (!elf_create_reloc(e->out, klp_relocs,
+ klp_reloc_off + offsetof(struct klp_reloc, sym),
+ klp_sym, addend, R_ABS64))
+ return -1;
+
+ return 0;
+}
+
+/* Copy a reloc and its symbol to the output object */
+static int clone_reloc(struct elfs *e, struct reloc *patched_reloc,
+ struct section *sec, unsigned long offset)
+{
+ struct symbol *patched_sym = patched_reloc->sym;
+ struct export *export = find_export(patched_sym);
+ long addend = reloc_addend(patched_reloc);
+ struct symbol *out_sym;
+ bool klp;
+
+ if (!is_reloc_allowed(patched_reloc)) {
+ ERROR_FUNC(patched_reloc->sec->base, reloc_offset(patched_reloc),
+ "missing symbol for reference to %s+%ld",
+ patched_sym->name, addend);
+ return -1;
+ }
+
+ klp = klp_reloc_needed(patched_reloc);
+
+ if (klp) {
+ if (clone_reloc_klp(e, patched_reloc, sec, offset, export))
+ return -1;
+
+ return 0;
+ }
+
+ /*
+ * Why !export sets 'data_too':
+ *
+ * Unexported non-klp symbols need to live in the patch module,
+ * otherwise there will be unresolved symbols. Notably, this includes:
+ *
+ * - New functions/data
+ * - String sections
+ * - Special section entries
+ * - Uncorrelated static local variables
+ * - UBSAN sections
+ */
+ out_sym = clone_symbol(e, patched_sym, patched_sym->included || !export);
+ if (!out_sym)
+ return -1;
+
+ /*
+ * For strings, all references use section symbols, thanks to
+ * section_reference_needed(). clone_symbol() has cloned an empty
+ * version of the string section. Now copy the string itself.
+ */
+ if (is_string_sec(patched_sym->sec)) {
+ const char *str = patched_sym->sec->data->d_buf + addend;
+
+ addend = elf_add_string(e->out, out_sym->sec, str);
+ if (addend == -1)
+ return -1;
+ }
+
+ if (!elf_create_reloc(e->out, sec, offset, out_sym, addend,
+ reloc_type(patched_reloc)))
+ return -1;
+
+ return 0;
+}
+
+/* Copy all relocs needed for a symbol's contents */
+static int clone_sym_relocs(struct elfs *e, struct symbol *patched_sym)
+{
+ struct section *patched_rsec = patched_sym->sec->rsec;
+ struct reloc *patched_reloc;
+ unsigned long start, end;
+ struct symbol *out_sym;
+
+ out_sym = patched_sym->clone;
+ if (!out_sym) {
+ ERROR("no clone for %s", patched_sym->name);
+ return -1;
+ }
+
+ if (!patched_rsec)
+ return 0;
+
+ if (!is_sec_sym(patched_sym) && !patched_sym->len)
+ return 0;
+
+ if (is_string_sec(patched_sym->sec))
+ return 0;
+
+ if (is_sec_sym(patched_sym)) {
+ start = 0;
+ end = sec_size(patched_sym->sec);
+ } else {
+ start = patched_sym->offset;
+ end = start + patched_sym->len;
+ }
+
+ for_each_reloc(patched_rsec, patched_reloc) {
+ unsigned long offset;
+
+ if (reloc_offset(patched_reloc) < start ||
+ reloc_offset(patched_reloc) >= end)
+ continue;
+
+ /*
+ * Skip any reloc referencing .altinstr_aux. Its code is
+ * always patched by alternatives. See ALTERNATIVE_TERNARY().
+ */
+ if (patched_reloc->sym->sec &&
+ !strcmp(patched_reloc->sym->sec->name, ".altinstr_aux"))
+ continue;
+
+ if (convert_reloc_sym(e->patched, patched_reloc)) {
+ ERROR_FUNC(patched_rsec->base, reloc_offset(patched_reloc),
+ "failed to convert reloc sym '%s' to its proper format",
+ patched_reloc->sym->name);
+ return -1;
+ }
+
+ offset = out_sym->offset + (reloc_offset(patched_reloc) - patched_sym->offset);
+
+ if (clone_reloc(e, patched_reloc, out_sym->sec, offset))
+ return -1;
+ }
+ return 0;
+
+}
+
+static int create_fake_symbol(struct elf *elf, struct section *sec,
+ unsigned long offset, size_t size)
+{
+ char name[SYM_NAME_LEN];
+ unsigned int type;
+ static int ctr;
+ char *c;
+
+ if (snprintf_check(name, SYM_NAME_LEN, "%s_%d", sec->name, ctr++))
+ return -1;
+
+ for (c = name; *c; c++)
+ if (*c == '.')
+ *c = '_';
+
+ /*
+ * STT_NOTYPE: Prevent objtool from validating .altinstr_replacement
+ * while still allowing objdump to disassemble it.
+ */
+ type = is_text_sec(sec) ? STT_NOTYPE : STT_OBJECT;
+ return elf_create_symbol(elf, name, sec, STB_LOCAL, type, offset, size) ? 0 : -1;
+}
+
+/*
+ * Special sections (alternatives, etc) are basically arrays of structs.
+ * For all the special sections, create a symbol for each struct entry. This
+ * is a bit cumbersome, but it makes the extracting of the individual entries
+ * much more straightforward.
+ *
+ * There are three ways to identify the entry sizes for a special section:
+ *
+ * 1) ELF section header sh_entsize: Ideally this would be used almost
+ * everywhere. But unfortunately the toolchains make it difficult. The
+ * assembler .[push]section directive syntax only takes entsize when
+ * combined with SHF_MERGE. But Clang disallows combining SHF_MERGE with
+ * SHF_WRITE. And some special sections do need to be writable.
+ *
+ * Another place this wouldn't work is .altinstr_replacement, whose entries
+ * don't have a fixed size.
+ *
+ * 2) ANNOTATE_DATA_SPECIAL: This is a lightweight objtool annotation which
+ * points to the beginning of each entry. The size of the entry is then
+ * inferred by the location of the subsequent annotation (or end of
+ * section).
+ *
+ * 3) Simple array of pointers: If the special section is just a basic array of
+ * pointers, the entry size can be inferred by the number of relocations.
+ * No annotations needed.
+ *
+ * Note I also tried to create per-entry symbols at the time of creation, in
+ * the original [inline] asm. Unfortunately, creating uniquely named symbols
+ * is trickier than one might think, especially with Clang inline asm. I
+ * eventually just gave up trying to make that work, in favor of using
+ * ANNOTATE_DATA_SPECIAL and creating the symbols here after the fact.
+ */
+static int create_fake_symbols(struct elf *elf)
+{
+ struct section *sec;
+ struct reloc *reloc;
+
+ /*
+ * 1) Make symbols for all the ANNOTATE_DATA_SPECIAL entries:
+ */
+
+ sec = find_section_by_name(elf, ".discard.annotate_data");
+ if (!sec || !sec->rsec)
+ return 0;
+
+ for_each_reloc(sec->rsec, reloc) {
+ unsigned long offset, size;
+ struct reloc *next_reloc;
+
+ if (annotype(elf, sec, reloc) != ANNOTYPE_DATA_SPECIAL)
+ continue;
+
+ offset = reloc_addend(reloc);
+
+ size = 0;
+ next_reloc = reloc;
+ for_each_reloc_continue(sec->rsec, next_reloc) {
+ if (annotype(elf, sec, next_reloc) != ANNOTYPE_DATA_SPECIAL ||
+ next_reloc->sym->sec != reloc->sym->sec)
+ continue;
+
+ size = reloc_addend(next_reloc) - offset;
+ break;
+ }
+
+ if (!size)
+ size = sec_size(reloc->sym->sec) - offset;
+
+ if (create_fake_symbol(elf, reloc->sym->sec, offset, size))
+ return -1;
+ }
+
+ /*
+ * 2) Make symbols for sh_entsize, and simple arrays of pointers:
+ */
+
+ for_each_sec(elf, sec) {
+ unsigned int entry_size;
+ unsigned long offset;
+
+ if (!is_special_section(sec) || find_symbol_by_offset(sec, 0))
+ continue;
+
+ if (!sec->rsec) {
+ ERROR("%s: missing special section relocations", sec->name);
+ return -1;
+ }
+
+ entry_size = sec->sh.sh_entsize;
+ if (!entry_size) {
+ entry_size = arch_reloc_size(sec->rsec->relocs);
+ if (sec_size(sec) != entry_size * sec_num_entries(sec->rsec)) {
+ ERROR("%s: missing special section entsize or annotations", sec->name);
+ return -1;
+ }
+ }
+
+ for (offset = 0; offset < sec_size(sec); offset += entry_size) {
+ if (create_fake_symbol(elf, sec, offset, entry_size))
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/* Keep a special section entry if it references an included function */
+static bool should_keep_special_sym(struct elf *elf, struct symbol *sym)
+{
+ struct reloc *reloc;
+
+ if (is_sec_sym(sym) || !sym->sec->rsec)
+ return false;
+
+ sym_for_each_reloc(elf, sym, reloc) {
+ if (convert_reloc_sym(elf, reloc))
+ continue;
+
+ if (is_func_sym(reloc->sym) && reloc->sym->included)
+ return true;
+ }
+
+ return false;
+}
+
+/*
+ * Klp relocations aren't allowed for __jump_table and .static_call_sites if
+ * the referenced symbol lives in a kernel module, because such klp relocs may
+ * be applied after static branch/call init, resulting in code corruption.
+ *
+ * Validate a special section entry to avoid that. Note that an inert
+ * tracepoint is harmless enough, in that case just skip the entry and print a
+ * warning. Otherwise, return an error.
+ *
+ * This is only a temporary limitation which will be fixed when livepatch adds
+ * support for submodules: fully self-contained modules which are embedded in
+ * the top-level livepatch module's data and which can be loaded on demand when
+ * their corresponding to-be-patched module gets loaded. Then klp relocs can
+ * be retired.
+ *
+ * Return:
+ * -1: error: validation failed
+ * 1: warning: tracepoint skipped
+ * 0: success
+ */
+static int validate_special_section_klp_reloc(struct elfs *e, struct symbol *sym)
+{
+ bool static_branch = !strcmp(sym->sec->name, "__jump_table");
+ bool static_call = !strcmp(sym->sec->name, ".static_call_sites");
+ struct symbol *code_sym = NULL;
+ unsigned long code_offset = 0;
+ struct reloc *reloc;
+ int ret = 0;
+
+ if (!static_branch && !static_call)
+ return 0;
+
+ sym_for_each_reloc(e->patched, sym, reloc) {
+ const char *sym_modname;
+ struct export *export;
+
+ /* Static branch/call keys are always STT_OBJECT */
+ if (reloc->sym->type != STT_OBJECT) {
+
+ /* Save code location which can be printed below */
+ if (reloc->sym->type == STT_FUNC && !code_sym) {
+ code_sym = reloc->sym;
+ code_offset = reloc_addend(reloc);
+ }
+
+ continue;
+ }
+
+ if (!klp_reloc_needed(reloc))
+ continue;
+
+ export = find_export(reloc->sym);
+ if (export) {
+ sym_modname = export->mod;
+ } else {
+ sym_modname = find_modname(e);
+ if (!sym_modname)
+ return -1;
+ }
+
+ /* vmlinux keys are ok */
+ if (!strcmp(sym_modname, "vmlinux"))
+ continue;
+
+ if (static_branch) {
+ if (strstarts(reloc->sym->name, "__tracepoint_")) {
+ WARN("%s: disabling unsupported tracepoint %s",
+ code_sym->name, reloc->sym->name + 13);
+ ret = 1;
+ continue;
+ }
+
+ ERROR("%s+0x%lx: unsupported static branch key %s. Use static_key_enabled() instead",
+ code_sym->name, code_offset, reloc->sym->name);
+ return -1;
+ }
+
+ /* static call */
+ if (strstarts(reloc->sym->name, "__SCK__tp_func_")) {
+ ret = 1;
+ continue;
+ }
+
+ ERROR("%s()+0x%lx: unsupported static call key %s. Use KLP_STATIC_CALL() instead",
+ code_sym->name, code_offset, reloc->sym->name);
+ return -1;
+ }
+
+ return ret;
+}
+
+static int clone_special_section(struct elfs *e, struct section *patched_sec)
+{
+ struct symbol *patched_sym;
+
+ /*
+ * Extract all special section symbols (and their dependencies) which
+ * reference included functions.
+ */
+ sec_for_each_sym(patched_sec, patched_sym) {
+ int ret;
+
+ if (!is_object_sym(patched_sym))
+ continue;
+
+ if (!should_keep_special_sym(e->patched, patched_sym))
+ continue;
+
+ ret = validate_special_section_klp_reloc(e, patched_sym);
+ if (ret < 0)
+ return -1;
+ if (ret > 0)
+ continue;
+
+ if (!clone_symbol(e, patched_sym, true))
+ return -1;
+ }
+
+ return 0;
+}
+
+/* Extract only the needed bits from special sections */
+static int clone_special_sections(struct elfs *e)
+{
+ struct section *patched_sec;
+
+ if (create_fake_symbols(e->patched))
+ return -1;
+
+ for_each_sec(e->patched, patched_sec) {
+ if (is_special_section(patched_sec)) {
+ if (clone_special_section(e, patched_sec))
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Create __klp_objects and __klp_funcs sections which are intermediate
+ * sections provided as input to the patch module's init code for building the
+ * klp_patch, klp_object and klp_func structs for the livepatch API.
+ */
+static int create_klp_sections(struct elfs *e)
+{
+ size_t obj_size = sizeof(struct klp_object_ext);
+ size_t func_size = sizeof(struct klp_func_ext);
+ struct section *obj_sec, *funcs_sec, *str_sec;
+ struct symbol *funcs_sym, *str_sym, *sym;
+ char sym_name[SYM_NAME_LEN];
+ unsigned int nr_funcs = 0;
+ const char *modname;
+ void *obj_data;
+ s64 addend;
+
+ obj_sec = elf_create_section_pair(e->out, KLP_OBJECTS_SEC, obj_size, 0, 0);
+ if (!obj_sec)
+ return -1;
+
+ funcs_sec = elf_create_section_pair(e->out, KLP_FUNCS_SEC, func_size, 0, 0);
+ if (!funcs_sec)
+ return -1;
+
+ funcs_sym = elf_create_section_symbol(e->out, funcs_sec);
+ if (!funcs_sym)
+ return -1;
+
+ str_sec = elf_create_section(e->out, KLP_STRINGS_SEC, 0, 0,
+ SHT_PROGBITS, 1,
+ SHF_ALLOC | SHF_STRINGS | SHF_MERGE);
+ if (!str_sec)
+ return -1;
+
+ if (elf_add_string(e->out, str_sec, "") == -1)
+ return -1;
+
+ str_sym = elf_create_section_symbol(e->out, str_sec);
+ if (!str_sym)
+ return -1;
+
+ /* allocate klp_object_ext */
+ obj_data = elf_add_data(e->out, obj_sec, NULL, obj_size);
+ if (!obj_data)
+ return -1;
+
+ modname = find_modname(e);
+ if (!modname)
+ return -1;
+
+ /* klp_object_ext.name */
+ if (strcmp(modname, "vmlinux")) {
+ addend = elf_add_string(e->out, str_sec, modname);
+ if (addend == -1)
+ return -1;
+
+ if (!elf_create_reloc(e->out, obj_sec,
+ offsetof(struct klp_object_ext, name),
+ str_sym, addend, R_ABS64))
+ return -1;
+ }
+
+ /* klp_object_ext.funcs */
+ if (!elf_create_reloc(e->out, obj_sec, offsetof(struct klp_object_ext, funcs),
+ funcs_sym, 0, R_ABS64))
+ return -1;
+
+ for_each_sym(e->out, sym) {
+ unsigned long offset = nr_funcs * func_size;
+ unsigned long sympos;
+ void *func_data;
+
+ if (!is_func_sym(sym) || sym->cold || !sym->clone || !sym->clone->changed)
+ continue;
+
+ /* allocate klp_func_ext */
+ func_data = elf_add_data(e->out, funcs_sec, NULL, func_size);
+ if (!func_data)
+ return -1;
+
+ /* klp_func_ext.old_name */
+ addend = elf_add_string(e->out, str_sec, sym->clone->twin->name);
+ if (addend == -1)
+ return -1;
+
+ if (!elf_create_reloc(e->out, funcs_sec,
+ offset + offsetof(struct klp_func_ext, old_name),
+ str_sym, addend, R_ABS64))
+ return -1;
+
+ /* klp_func_ext.new_func */
+ if (!elf_create_reloc(e->out, funcs_sec,
+ offset + offsetof(struct klp_func_ext, new_func),
+ sym, 0, R_ABS64))
+ return -1;
+
+ /* klp_func_ext.sympos */
+ BUILD_BUG_ON(sizeof(sympos) != sizeof_field(struct klp_func_ext, sympos));
+ sympos = find_sympos(e->orig, sym->clone->twin);
+ if (sympos == ULONG_MAX)
+ return -1;
+ memcpy(func_data + offsetof(struct klp_func_ext, sympos), &sympos,
+ sizeof_field(struct klp_func_ext, sympos));
+
+ nr_funcs++;
+ }
+
+ /* klp_object_ext.nr_funcs */
+ BUILD_BUG_ON(sizeof(nr_funcs) != sizeof_field(struct klp_object_ext, nr_funcs));
+ memcpy(obj_data + offsetof(struct klp_object_ext, nr_funcs), &nr_funcs,
+ sizeof_field(struct klp_object_ext, nr_funcs));
+
+ /*
+ * Find callback pointers created by KLP_PRE_PATCH_CALLBACK() and
+ * friends, and add them to the klp object.
+ */
+
+ if (snprintf_check(sym_name, SYM_NAME_LEN, KLP_PRE_PATCH_PREFIX "%s", modname))
+ return -1;
+
+ sym = find_symbol_by_name(e->out, sym_name);
+ if (sym) {
+ struct reloc *reloc;
+
+ reloc = find_reloc_by_dest(e->out, sym->sec, sym->offset);
+
+ if (!elf_create_reloc(e->out, obj_sec,
+ offsetof(struct klp_object_ext, callbacks) +
+ offsetof(struct klp_callbacks, pre_patch),
+ reloc->sym, reloc_addend(reloc), R_ABS64))
+ return -1;
+ }
+
+ if (snprintf_check(sym_name, SYM_NAME_LEN, KLP_POST_PATCH_PREFIX "%s", modname))
+ return -1;
+
+ sym = find_symbol_by_name(e->out, sym_name);
+ if (sym) {
+ struct reloc *reloc;
+
+ reloc = find_reloc_by_dest(e->out, sym->sec, sym->offset);
+
+ if (!elf_create_reloc(e->out, obj_sec,
+ offsetof(struct klp_object_ext, callbacks) +
+ offsetof(struct klp_callbacks, post_patch),
+ reloc->sym, reloc_addend(reloc), R_ABS64))
+ return -1;
+ }
+
+ if (snprintf_check(sym_name, SYM_NAME_LEN, KLP_PRE_UNPATCH_PREFIX "%s", modname))
+ return -1;
+
+ sym = find_symbol_by_name(e->out, sym_name);
+ if (sym) {
+ struct reloc *reloc;
+
+ reloc = find_reloc_by_dest(e->out, sym->sec, sym->offset);
+
+ if (!elf_create_reloc(e->out, obj_sec,
+ offsetof(struct klp_object_ext, callbacks) +
+ offsetof(struct klp_callbacks, pre_unpatch),
+ reloc->sym, reloc_addend(reloc), R_ABS64))
+ return -1;
+ }
+
+ if (snprintf_check(sym_name, SYM_NAME_LEN, KLP_POST_UNPATCH_PREFIX "%s", modname))
+ return -1;
+
+ sym = find_symbol_by_name(e->out, sym_name);
+ if (sym) {
+ struct reloc *reloc;
+
+ reloc = find_reloc_by_dest(e->out, sym->sec, sym->offset);
+
+ if (!elf_create_reloc(e->out, obj_sec,
+ offsetof(struct klp_object_ext, callbacks) +
+ offsetof(struct klp_callbacks, post_unpatch),
+ reloc->sym, reloc_addend(reloc), R_ABS64))
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Copy all .modinfo import_ns= tags to ensure all namespaced exported symbols
+ * can be accessed via normal relocs.
+ */
+static int copy_import_ns(struct elfs *e)
+{
+ struct section *patched_sec, *out_sec = NULL;
+ char *import_ns, *data_end;
+
+ patched_sec = find_section_by_name(e->patched, ".modinfo");
+ if (!patched_sec)
+ return 0;
+
+ import_ns = patched_sec->data->d_buf;
+ if (!import_ns)
+ return 0;
+
+ for (data_end = import_ns + sec_size(patched_sec);
+ import_ns < data_end;
+ import_ns += strlen(import_ns) + 1) {
+
+ import_ns = memmem(import_ns, data_end - import_ns, "import_ns=", 10);
+ if (!import_ns)
+ return 0;
+
+ if (!out_sec) {
+ out_sec = find_section_by_name(e->out, ".modinfo");
+ if (!out_sec) {
+ out_sec = elf_create_section(e->out, ".modinfo", 0,
+ patched_sec->sh.sh_entsize,
+ patched_sec->sh.sh_type,
+ patched_sec->sh.sh_addralign,
+ patched_sec->sh.sh_flags);
+ if (!out_sec)
+ return -1;
+ }
+ }
+
+ if (!elf_add_data(e->out, out_sec, import_ns, strlen(import_ns) + 1))
+ return -1;
+ }
+
+ return 0;
+}
+
+int cmd_klp_diff(int argc, const char **argv)
+{
+ struct elfs e = {0};
+
+ argc = parse_options(argc, argv, klp_diff_options, klp_diff_usage, 0);
+ if (argc != 3)
+ usage_with_options(klp_diff_usage, klp_diff_options);
+
+ objname = argv[0];
+
+ e.orig = elf_open_read(argv[0], O_RDONLY);
+ e.patched = elf_open_read(argv[1], O_RDONLY);
+ e.out = NULL;
+
+ if (!e.orig || !e.patched)
+ return -1;
+
+ if (read_exports())
+ return -1;
+
+ if (read_sym_checksums(e.orig))
+ return -1;
+
+ if (read_sym_checksums(e.patched))
+ return -1;
+
+ if (correlate_symbols(&e))
+ return -1;
+
+ if (mark_changed_functions(&e))
+ return 0;
+
+ e.out = elf_create_file(&e.orig->ehdr, argv[2]);
+ if (!e.out)
+ return -1;
+
+ if (clone_included_functions(&e))
+ return -1;
+
+ if (clone_special_sections(&e))
+ return -1;
+
+ if (create_klp_sections(&e))
+ return -1;
+
+ if (copy_import_ns(&e))
+ return -1;
+
+ if (elf_write(e.out))
+ return -1;
+
+ return elf_close(e.out);
+}
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index 5c8b974ad0f9d..c8f611c1320d1 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -16,8 +16,6 @@
#include <objtool/objtool.h>
#include <objtool/warn.h>
-bool help;
-
static struct objtool_file file;
struct objtool_file *objtool_open_read(const char *filename)
@@ -71,6 +69,39 @@ int objtool_pv_add(struct objtool_file *f, int idx, struct symbol *func)
return 0;
}
+char *top_level_dir(const char *file)
+{
+ ssize_t len, self_len, file_len;
+ char self[PATH_MAX], *str;
+ int i;
+
+ len = readlink("/proc/self/exe", self, sizeof(self) - 1);
+ if (len <= 0)
+ return NULL;
+ self[len] = '\0';
+
+ for (i = 0; i < 3; i++) {
+ char *s = strrchr(self, '/');
+ if (!s)
+ return NULL;
+ *s = '\0';
+ }
+
+ self_len = strlen(self);
+ file_len = strlen(file);
+
+ str = malloc(self_len + file_len + 2);
+ if (!str)
+ return NULL;
+
+ memcpy(str, self, self_len);
+ str[self_len] = '/';
+ strcpy(str + self_len + 1, file);
+
+ return str;
+}
+
+
int main(int argc, const char **argv)
{
static const char *UNUSED = "OBJTOOL_NOT_IMPLEMENTED";
@@ -79,5 +110,11 @@ int main(int argc, const char **argv)
exec_cmd_init("objtool", UNUSED, UNUSED, UNUSED);
pager_init(UNUSED);
+ if (argc > 1 && !strcmp(argv[1], "klp")) {
+ argc--;
+ argv++;
+ return cmd_klp(argc, argv);
+ }
+
return objtool_run(argc, argv);
}
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index 86d64e3ac6f73..e38167ca56a95 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -17,6 +17,7 @@ arch/x86/include/asm/emulate_prefix.h
arch/x86/lib/x86-opcode-map.txt
arch/x86/tools/gen-insn-attr-x86.awk
include/linux/interval_tree_generic.h
+include/linux/livepatch_external.h
include/linux/static_call_types.h
"
diff --git a/tools/objtool/weak.c b/tools/objtool/weak.c
index d83f607733b04..d6562f292259e 100644
--- a/tools/objtool/weak.c
+++ b/tools/objtool/weak.c
@@ -8,6 +8,8 @@
#include <stdbool.h>
#include <errno.h>
#include <objtool/objtool.h>
+#include <objtool/arch.h>
+#include <objtool/builtin.h>
#define UNSUPPORTED(name) \
({ \
@@ -24,3 +26,8 @@ int __weak orc_create(struct objtool_file *file)
{
UNSUPPORTED("ORC");
}
+
+int __weak cmd_klp(int argc, const char **argv)
+{
+ UNSUPPORTED("klp");
+}
--
2.50.0Add a --debug option to klp diff which prints cloning decisions and an
indented dependency tree for all cloned symbols and relocations. This
helps visualize which symbols and relocations were included and why.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/include/objtool/warn.h | 21 ++++++++
tools/objtool/klp-diff.c | 75 ++++++++++++++++++++++++++++
tools/objtool/objtool.c | 3 ++
3 files changed, 99 insertions(+)
diff --git a/tools/objtool/include/objtool/warn.h b/tools/objtool/include/objtool/warn.h
index 29173a1368d79..e88322d97573e 100644
--- a/tools/objtool/include/objtool/warn.h
+++ b/tools/objtool/include/objtool/warn.h
@@ -102,6 +102,10 @@ static inline char *offstr(struct section *sec, unsigned long offset)
#define ERROR_FUNC(sec, offset, format, ...) __WARN_FUNC(ERROR_STR, sec, offset, format, ##__VA_ARGS__)
#define ERROR_INSN(insn, format, ...) WARN_FUNC(insn->sec, insn->offset, format, ##__VA_ARGS__)
+extern bool debug;
+extern int indent;
+
+static inline void unindent(int *unused) { indent--; }
#define __dbg(format, ...) \
fprintf(stderr, \
@@ -110,6 +114,23 @@ static inline char *offstr(struct section *sec, unsigned long offset)
objname ? ": " : "", \
##__VA_ARGS__)
+#define dbg(args...) \
+({ \
+ if (unlikely(debug)) \
+ __dbg(args); \
+})
+
+#define __dbg_indent(format, ...) \
+({ \
+ if (unlikely(debug)) \
+ __dbg("%*s" format, indent * 8, "", ##__VA_ARGS__); \
+})
+
+#define dbg_indent(args...) \
+ int __attribute__((cleanup(unindent))) __dummy_##__COUNTER__; \
+ __dbg_indent(args); \
+ indent++
+
#define dbg_checksum(func, insn, checksum) \
({ \
if (unlikely(insn->sym && insn->sym->pfunc && \
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 0d69b621a26cf..817d44394a78c 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -38,6 +38,8 @@ static const char * const klp_diff_usage[] = {
};
static const struct option klp_diff_options[] = {
+ OPT_GROUP("Options:"),
+ OPT_BOOLEAN('d', "debug", &debug, "enable debug output"),
OPT_END(),
};
@@ -48,6 +50,38 @@ static inline u32 str_hash(const char *str)
return jhash(str, strlen(str), 0);
}
+static char *escape_str(const char *orig)
+{
+ size_t len = 0;
+ const char *a;
+ char *b, *new;
+
+ for (a = orig; *a; a++) {
+ switch (*a) {
+ case '\001': len += 5; break;
+ case '\n':
+ case '\t': len += 2; break;
+ default: len++;
+ }
+ }
+
+ new = malloc(len + 1);
+ if (!new)
+ return NULL;
+
+ for (a = orig, b = new; *a; a++) {
+ switch (*a) {
+ case '\001': memcpy(b, "<SOH>", 5); b += 5; break;
+ case '\n': *b++ = '\\'; *b++ = 'n'; break;
+ case '\t': *b++ = '\\'; *b++ = 't'; break;
+ default: *b++ = *a;
+ }
+ }
+
+ *b = '\0';
+ return new;
+}
+
static int read_exports(void)
{
const char *symvers = "Module.symvers";
@@ -528,6 +562,28 @@ static struct symbol *__clone_symbol(struct elf *elf, struct symbol *patched_sym
return out_sym;
}
+static const char *sym_type(struct symbol *sym)
+{
+ switch (sym->type) {
+ case STT_NOTYPE: return "NOTYPE";
+ case STT_OBJECT: return "OBJECT";
+ case STT_FUNC: return "FUNC";
+ case STT_SECTION: return "SECTION";
+ case STT_FILE: return "FILE";
+ default: return "UNKNOWN";
+ }
+}
+
+static const char *sym_bind(struct symbol *sym)
+{
+ switch (sym->bind) {
+ case STB_LOCAL: return "LOCAL";
+ case STB_GLOBAL: return "GLOBAL";
+ case STB_WEAK: return "WEAK";
+ default: return "UNKNOWN";
+ }
+}
+
/*
* Copy a symbol to the output object, optionally including its data and
* relocations.
@@ -540,6 +596,8 @@ static struct symbol *clone_symbol(struct elfs *e, struct symbol *patched_sym,
if (patched_sym->clone)
return patched_sym->clone;
+ dbg_indent("%s%s", patched_sym->name, data_too ? " [+DATA]" : "");
+
/* Make sure the prefix gets cloned first */
if (is_func_sym(patched_sym) && data_too) {
pfx = get_func_prefix(patched_sym);
@@ -902,6 +960,8 @@ static int clone_reloc_klp(struct elfs *e, struct reloc *patched_reloc,
klp_sym = find_symbol_by_name(e->out, sym_name);
if (!klp_sym) {
+ __dbg_indent("%s", sym_name);
+
/* STB_WEAK: avoid modpost undefined symbol warnings */
klp_sym = elf_create_symbol(e->out, sym_name, NULL,
STB_WEAK, patched_sym->type, 0, 0);
@@ -950,6 +1010,17 @@ static int clone_reloc_klp(struct elfs *e, struct reloc *patched_reloc,
return 0;
}
+#define dbg_clone_reloc(sec, offset, patched_sym, addend, export, klp) \
+ dbg_indent("%s+0x%lx: %s%s0x%lx [%s%s%s%s%s%s]", \
+ sec->name, offset, patched_sym->name, \
+ addend >= 0 ? "+" : "-", labs(addend), \
+ sym_type(patched_sym), \
+ patched_sym->type == STT_SECTION ? "" : " ", \
+ patched_sym->type == STT_SECTION ? "" : sym_bind(patched_sym), \
+ is_undef_sym(patched_sym) ? " UNDEF" : "", \
+ export ? " EXPORTED" : "", \
+ klp ? " KLP" : "")
+
/* Copy a reloc and its symbol to the output object */
static int clone_reloc(struct elfs *e, struct reloc *patched_reloc,
struct section *sec, unsigned long offset)
@@ -969,6 +1040,8 @@ static int clone_reloc(struct elfs *e, struct reloc *patched_reloc,
klp = klp_reloc_needed(patched_reloc);
+ dbg_clone_reloc(sec, offset, patched_sym, addend, export, klp);
+
if (klp) {
if (clone_reloc_klp(e, patched_reloc, sec, offset, export))
return -1;
@@ -1000,6 +1073,8 @@ static int clone_reloc(struct elfs *e, struct reloc *patched_reloc,
if (is_string_sec(patched_sym->sec)) {
const char *str = patched_sym->sec->data->d_buf + addend;
+ __dbg_indent("\"%s\"", escape_str(str));
+
addend = elf_add_string(e->out, out_sym->sec, str);
if (addend == -1)
return -1;
diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index c8f611c1320d1..3c26ed561c7ef 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -16,6 +16,9 @@
#include <objtool/objtool.h>
#include <objtool/warn.h>
+bool debug;
+int indent;
+
static struct objtool_file file;
struct objtool_file *objtool_open_read(const char *filename)
--
2.50.0Livepatch needs some ELF magic which linkers don't like:
- Two relocation sections (.rela*, .klp.rela*) for the same text
section.
- Use of SHN_LIVEPATCH to mark livepatch symbols.
Unfortunately linkers tend to mangle such things. To work around that,
klp diff generates a linker-compliant intermediate binary which encodes
the relevant KLP section/reloc/symbol metadata.
After module linking, the .ko then needs to be converted to an actual
livepatch module. Introduce a new klp post-link subcommand to do so.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/Build | 2 +-
tools/objtool/builtin-klp.c | 1 +
tools/objtool/include/objtool/klp.h | 4 +
tools/objtool/klp-post-link.c | 168 ++++++++++++++++++++++++++++
4 files changed, 174 insertions(+), 1 deletion(-)
create mode 100644 tools/objtool/klp-post-link.c
diff --git a/tools/objtool/Build b/tools/objtool/Build
index 0b01657671d7f..8cd71b9a5eef1 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -9,7 +9,7 @@ objtool-y += elf.o
objtool-y += objtool.o
objtool-$(BUILD_ORC) += orc_gen.o orc_dump.o
-objtool-$(BUILD_KLP) += builtin-klp.o klp-diff.o
+objtool-$(BUILD_KLP) += builtin-klp.o klp-diff.o klp-post-link.o
objtool-y += libstring.o
objtool-y += libctype.o
diff --git a/tools/objtool/builtin-klp.c b/tools/objtool/builtin-klp.c
index 9b13dd1182af1..56d5a5b92f725 100644
--- a/tools/objtool/builtin-klp.c
+++ b/tools/objtool/builtin-klp.c
@@ -14,6 +14,7 @@ struct subcmd {
static struct subcmd subcmds[] = {
{ "diff", "Generate binary diff of two object files", cmd_klp_diff, },
+ { "post-link", "Finalize klp symbols/relocs after module linking", cmd_klp_post_link, },
};
static void cmd_klp_usage(void)
diff --git a/tools/objtool/include/objtool/klp.h b/tools/objtool/include/objtool/klp.h
index 07928fac059b5..ad830a7ce55b6 100644
--- a/tools/objtool/include/objtool/klp.h
+++ b/tools/objtool/include/objtool/klp.h
@@ -2,6 +2,9 @@
#ifndef _OBJTOOL_KLP_H
#define _OBJTOOL_KLP_H
+#define SHF_RELA_LIVEPATCH 0x00100000
+#define SHN_LIVEPATCH 0xff20
+
/*
* __klp_objects and __klp_funcs are created by klp diff and used by the patch
* module init code to build the klp_patch, klp_object and klp_func structs
@@ -27,5 +30,6 @@ struct klp_reloc {
};
int cmd_klp_diff(int argc, const char **argv);
+int cmd_klp_post_link(int argc, const char **argv);
#endif /* _OBJTOOL_KLP_H */
diff --git a/tools/objtool/klp-post-link.c b/tools/objtool/klp-post-link.c
new file mode 100644
index 0000000000000..c013e39957b11
--- /dev/null
+++ b/tools/objtool/klp-post-link.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Read the intermediate KLP reloc/symbol representations created by klp diff
+ * and convert them to the proper format required by livepatch. This needs to
+ * run last to avoid linker wreckage. Linkers don't tend to handle the "two
+ * rela sections for a single base section" case very well, nor do they like
+ * SHN_LIVEPATCH.
+ *
+ * This is the final tool in the livepatch module generation pipeline:
+ *
+ * kernel builds -> objtool klp diff -> module link -> objtool klp post-link
+ */
+
+#include <fcntl.h>
+#include <gelf.h>
+#include <objtool/objtool.h>
+#include <objtool/warn.h>
+#include <objtool/klp.h>
+#include <objtool/util.h>
+#include <linux/livepatch_external.h>
+
+static int fix_klp_relocs(struct elf *elf)
+{
+ struct section *symtab, *klp_relocs;
+
+ klp_relocs = find_section_by_name(elf, KLP_RELOCS_SEC);
+ if (!klp_relocs)
+ return 0;
+
+ symtab = find_section_by_name(elf, ".symtab");
+ if (!symtab) {
+ ERROR("missing .symtab");
+ return -1;
+ }
+
+ for (int i = 0; i < sec_size(klp_relocs) / sizeof(struct klp_reloc); i++) {
+ struct klp_reloc *klp_reloc;
+ unsigned long klp_reloc_off;
+ struct section *sec, *tmp, *klp_rsec;
+ unsigned long offset;
+ struct reloc *reloc;
+ char sym_modname[64];
+ char rsec_name[SEC_NAME_LEN];
+ u64 addend;
+ struct symbol *sym, *klp_sym;
+
+ klp_reloc_off = i * sizeof(*klp_reloc);
+ klp_reloc = klp_relocs->data->d_buf + klp_reloc_off;
+
+ /*
+ * Read __klp_relocs[i]:
+ */
+
+ /* klp_reloc.sec_offset */
+ reloc = find_reloc_by_dest(elf, klp_relocs,
+ klp_reloc_off + offsetof(struct klp_reloc, offset));
+ if (!reloc) {
+ ERROR("malformed " KLP_RELOCS_SEC " section");
+ return -1;
+ }
+
+ sec = reloc->sym->sec;
+ offset = reloc_addend(reloc);
+
+ /* klp_reloc.sym */
+ reloc = find_reloc_by_dest(elf, klp_relocs,
+ klp_reloc_off + offsetof(struct klp_reloc, sym));
+ if (!reloc) {
+ ERROR("malformed " KLP_RELOCS_SEC " section");
+ return -1;
+ }
+
+ klp_sym = reloc->sym;
+ addend = reloc_addend(reloc);
+
+ /* symbol format: .klp.sym.modname.sym_name,sympos */
+ if (sscanf(klp_sym->name + strlen(KLP_SYM_PREFIX), "%55[^.]", sym_modname) != 1)
+ ERROR("can't find modname in klp symbol '%s'", klp_sym->name);
+
+ /*
+ * Create the KLP rela:
+ */
+
+ /* section format: .klp.rela.sec_objname.section_name */
+ if (snprintf_check(rsec_name, SEC_NAME_LEN,
+ KLP_RELOC_SEC_PREFIX "%s.%s",
+ sym_modname, sec->name))
+ return -1;
+
+ klp_rsec = find_section_by_name(elf, rsec_name);
+ if (!klp_rsec) {
+ klp_rsec = elf_create_section(elf, rsec_name, 0,
+ elf_rela_size(elf),
+ SHT_RELA, elf_addr_size(elf),
+ SHF_ALLOC | SHF_INFO_LINK | SHF_RELA_LIVEPATCH);
+ if (!klp_rsec)
+ return -1;
+
+ klp_rsec->sh.sh_link = symtab->idx;
+ klp_rsec->sh.sh_info = sec->idx;
+ klp_rsec->base = sec;
+ }
+
+ tmp = sec->rsec;
+ sec->rsec = klp_rsec;
+ if (!elf_create_reloc(elf, sec, offset, klp_sym, addend, klp_reloc->type))
+ return -1;
+ sec->rsec = tmp;
+
+ /*
+ * Fix up the corresponding KLP symbol:
+ */
+
+ klp_sym->sym.st_shndx = SHN_LIVEPATCH;
+ if (!gelf_update_sym(symtab->data, klp_sym->idx, &klp_sym->sym)) {
+ ERROR_ELF("gelf_update_sym");
+ return -1;
+ }
+
+ /*
+ * Disable the original non-KLP reloc by converting it to R_*_NONE:
+ */
+
+ reloc = find_reloc_by_dest(elf, sec, offset);
+ sym = reloc->sym;
+ sym->sym.st_shndx = SHN_LIVEPATCH;
+ set_reloc_type(elf, reloc, 0);
+ if (!gelf_update_sym(symtab->data, sym->idx, &sym->sym)) {
+ ERROR_ELF("gelf_update_sym");
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * This runs on the livepatch module after all other linking has been done. It
+ * converts the intermediate __klp_relocs section into proper KLP relocs to be
+ * processed by livepatch. This needs to run last to avoid linker wreckage.
+ * Linkers don't tend to handle the "two rela sections for a single base
+ * section" case very well, nor do they appreciate SHN_LIVEPATCH.
+ */
+int cmd_klp_post_link(int argc, const char **argv)
+{
+ struct elf *elf;
+
+ argc--;
+ argv++;
+
+ if (argc != 1) {
+ fprintf(stderr, "%d\n", argc);
+ fprintf(stderr, "usage: objtool link <file.ko>\n");
+ return -1;
+ }
+
+ elf = elf_open_read(argv[0], O_RDWR);
+ if (!elf)
+ return -1;
+
+ if (fix_klp_relocs(elf))
+ return -1;
+
+ if (elf_write(elf))
+ return -1;
+
+ return elf_close(elf);
+}
--
2.50.0The prefix symbol creation code currently ignores all errors, presumably
because some functions don't have the leading NOPs.
Shuffle the code around a bit, improve the error handling and document
why some errors are ignored.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 59 ++++++++++++++++++++++-------
tools/objtool/elf.c | 17 ---------
tools/objtool/include/objtool/elf.h | 2 -
3 files changed, 46 insertions(+), 32 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 6eaae3c007486..6a9ce090a2cde 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -15,6 +15,7 @@
#include <objtool/special.h>
#include <objtool/warn.h>
#include <objtool/checksum.h>
+#include <objtool/util.h>
#include <linux/objtool_types.h>
#include <linux/hashtable.h>
@@ -4243,37 +4244,71 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
return false;
}
-static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
+/*
+ * For FineIBT or kCFI, a certain number of bytes preceding the function may be
+ * NOPs. Those NOPs may be rewritten at runtime and executed, so give them a
+ * proper function name: __pfx_<func>.
+ *
+ * The NOPs may not exist for the following cases:
+ *
+ * - compiler cloned functions (*.cold, *.part0, etc)
+ * - asm functions created with inline asm or without SYM_FUNC_START()
+ *
+ * So return 0 if the NOPs are missing or the function already has a prefix
+ * symbol.
+ */
+static int create_prefix_symbol(struct objtool_file *file, struct symbol *func)
{
struct instruction *insn, *prev;
+ char name[SYM_NAME_LEN];
struct cfi_state *cfi;
- insn = find_insn(file, func->sec, func->offset);
- if (!insn)
+ if (!is_func_sym(func) || is_prefix_func(func) ||
+ func->cold || func->static_call_tramp)
+ return 0;
+
+ if ((strlen(func->name) + sizeof("__pfx_") > SYM_NAME_LEN)) {
+ WARN("%s: symbol name too long, can't create __pfx_ symbol",
+ func->name);
+ return 0;
+ }
+
+ if (snprintf_check(name, SYM_NAME_LEN, "__pfx_%s", func->name))
return -1;
+ insn = find_insn(file, func->sec, func->offset);
+ if (!insn) {
+ WARN("%s: can't find starting instruction", func->name);
+ return -1;
+ }
+
for (prev = prev_insn_same_sec(file, insn);
prev;
prev = prev_insn_same_sec(file, prev)) {
u64 offset;
if (prev->type != INSN_NOP)
- return -1;
+ return 0;
offset = func->offset - prev->offset;
if (offset > opts.prefix)
- return -1;
+ return 0;
if (offset < opts.prefix)
continue;
- elf_create_prefix_symbol(file->elf, func, opts.prefix);
+ if (!elf_create_symbol(file->elf, name, func->sec,
+ GELF_ST_BIND(func->sym.st_info),
+ GELF_ST_TYPE(func->sym.st_info),
+ prev->offset, opts.prefix))
+ return -1;
+
break;
}
if (!prev)
- return -1;
+ return 0;
if (!insn->cfi) {
/*
@@ -4291,7 +4326,7 @@ static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
return 0;
}
-static int add_prefix_symbols(struct objtool_file *file)
+static int create_prefix_symbols(struct objtool_file *file)
{
struct section *sec;
struct symbol *func;
@@ -4301,10 +4336,8 @@ static int add_prefix_symbols(struct objtool_file *file)
continue;
sec_for_each_sym(sec, func) {
- if (!is_func_sym(func))
- continue;
-
- add_prefix_symbol(file, func);
+ if (create_prefix_symbol(file, func))
+ return -1;
}
}
@@ -4931,7 +4964,7 @@ int check(struct objtool_file *file)
}
if (opts.prefix) {
- ret = add_prefix_symbols(file);
+ ret = create_prefix_symbols(file);
if (ret)
goto out;
}
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index e1daae0630be9..4bb7ce994b6a7 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -942,23 +942,6 @@ struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec)
return sym;
}
-struct symbol *
-elf_create_prefix_symbol(struct elf *elf, struct symbol *orig, size_t size)
-{
- size_t namelen = strlen(orig->name) + sizeof("__pfx_");
- char name[SYM_NAME_LEN];
- unsigned long offset;
-
- snprintf(name, namelen, "__pfx_%s", orig->name);
-
- offset = orig->sym.st_value - size;
-
- return elf_create_symbol(elf, name, orig->sec,
- GELF_ST_BIND(orig->sym.st_info),
- GELF_ST_TYPE(orig->sym.st_info),
- offset, size);
-}
-
struct reloc *elf_init_reloc(struct elf *elf, struct section *rsec,
unsigned int reloc_idx, unsigned long offset,
struct symbol *sym, s64 addend, unsigned int type)
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index e2cd817fca522..60f844e43c5a2 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -148,8 +148,6 @@ struct symbol *elf_create_symbol(struct elf *elf, const char *name,
unsigned int type, unsigned long offset,
size_t size);
struct symbol *elf_create_section_symbol(struct elf *elf, struct section *sec);
-struct symbol *elf_create_prefix_symbol(struct elf *elf, struct symbol *orig,
- size_t size);
void *elf_add_data(struct elf *elf, struct section *sec, const void *data,
size_t size);
--
2.50.0In preparation for klp-build, enable "classic" objtool to work on
livepatch modules:
- Avoid duplicate symbol/section warnings for prefix symbols and the
.static_call_sites and __mcount_loc sections which may have already
been extracted by klp diff.
- Add __klp_funcs to the IBT function pointer section whitelist.
- Prevent KLP symbols from getting incorrectly classified as cold
subfunctions.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
tools/objtool/check.c | 52 ++++++++++++++++++++++---
tools/objtool/elf.c | 5 ++-
tools/objtool/include/objtool/elf.h | 1 +
tools/objtool/include/objtool/objtool.h | 2 +-
4 files changed, 53 insertions(+), 7 deletions(-)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 6a9ce090a2cde..ba591a325d52e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3,6 +3,7 @@
* Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
*/
+#define _GNU_SOURCE /* memmem() */
#include <string.h>
#include <stdlib.h>
#include <inttypes.h>
@@ -611,6 +612,20 @@ static int init_pv_ops(struct objtool_file *file)
return 0;
}
+static bool is_livepatch_module(struct objtool_file *file)
+{
+ struct section *sec;
+
+ if (!opts.module)
+ return false;
+
+ sec = find_section_by_name(file->elf, ".modinfo");
+ if (!sec)
+ return false;
+
+ return memmem(sec->data->d_buf, sec_size(sec), "\0livepatch=Y", 12);
+}
+
static int create_static_call_sections(struct objtool_file *file)
{
struct static_call_site *site;
@@ -622,7 +637,14 @@ static int create_static_call_sections(struct objtool_file *file)
sec = find_section_by_name(file->elf, ".static_call_sites");
if (sec) {
- WARN("file already has .static_call_sites section, skipping");
+ /*
+ * Livepatch modules may have already extracted the static call
+ * site entries to take advantage of vmlinux static call
+ * privileges.
+ */
+ if (!file->klp)
+ WARN("file already has .static_call_sites section, skipping");
+
return 0;
}
@@ -666,7 +688,7 @@ static int create_static_call_sections(struct objtool_file *file)
key_sym = find_symbol_by_name(file->elf, tmp);
if (!key_sym) {
- if (!opts.module) {
+ if (!opts.module || file->klp) {
ERROR("static_call: can't find static_call_key symbol: %s", tmp);
return -1;
}
@@ -885,7 +907,13 @@ static int create_mcount_loc_sections(struct objtool_file *file)
sec = find_section_by_name(file->elf, "__mcount_loc");
if (sec) {
- WARN("file already has __mcount_loc section, skipping");
+ /*
+ * Livepatch modules have already extracted their __mcount_loc
+ * entries to cover the !CONFIG_FTRACE_MCOUNT_USE_OBJTOOL case.
+ */
+ if (!file->klp)
+ WARN("file already has __mcount_loc section, skipping");
+
return 0;
}
@@ -2579,6 +2607,8 @@ static bool validate_branch_enabled(void)
static int decode_sections(struct objtool_file *file)
{
+ file->klp = is_livepatch_module(file);
+
mark_rodata(file);
if (init_pv_ops(file))
@@ -4254,6 +4284,9 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
* - compiler cloned functions (*.cold, *.part0, etc)
* - asm functions created with inline asm or without SYM_FUNC_START()
*
+ * Also, the function may already have a prefix from a previous objtool run
+ * (livepatch extracted functions, or manually running objtool multiple times).
+ *
* So return 0 if the NOPs are missing or the function already has a prefix
* symbol.
*/
@@ -4276,6 +4309,14 @@ static int create_prefix_symbol(struct objtool_file *file, struct symbol *func)
if (snprintf_check(name, SYM_NAME_LEN, "__pfx_%s", func->name))
return -1;
+ if (file->klp) {
+ struct symbol *pfx;
+
+ pfx = find_symbol_by_offset(func->sec, func->offset - opts.prefix);
+ if (pfx && is_prefix_func(pfx) && !strcmp(pfx->name, name))
+ return 0;
+ }
+
insn = find_insn(file, func->sec, func->offset);
if (!insn) {
WARN("%s: can't find starting instruction", func->name);
@@ -4628,6 +4669,7 @@ static int validate_ibt(struct objtool_file *file)
!strncmp(sec->name, ".debug", 6) ||
!strcmp(sec->name, ".altinstructions") ||
!strcmp(sec->name, ".ibt_endbr_seal") ||
+ !strcmp(sec->name, ".kcfi_traps") ||
!strcmp(sec->name, ".orc_unwind_ip") ||
!strcmp(sec->name, ".retpoline_sites") ||
!strcmp(sec->name, ".smp_locks") ||
@@ -4637,12 +4679,12 @@ static int validate_ibt(struct objtool_file *file)
!strcmp(sec->name, "__bug_table") ||
!strcmp(sec->name, "__ex_table") ||
!strcmp(sec->name, "__jump_table") ||
+ !strcmp(sec->name, "__klp_funcs") ||
!strcmp(sec->name, "__mcount_loc") ||
- !strcmp(sec->name, ".kcfi_traps") ||
!strcmp(sec->name, ".llvm.call-graph-profile") ||
!strcmp(sec->name, ".llvm_bb_addr_map") ||
!strcmp(sec->name, "__tracepoints") ||
- strstr(sec->name, "__patchable_function_entries"))
+ !strcmp(sec->name, "__patchable_function_entries"))
continue;
for_each_reloc(sec->rsec, reloc)
diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 4bb7ce994b6a7..5feeefc7fc8f8 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -499,7 +499,10 @@ static int elf_add_symbol(struct elf *elf, struct symbol *sym)
strstarts(sym->name, "__pi___cfi_")))
sym->prefix = 1;
- if (is_func_sym(sym) && strstr(sym->name, ".cold"))
+ if (strstarts(sym->name, ".klp.sym"))
+ sym->klp = 1;
+
+ if (!sym->klp && is_func_sym(sym) && strstr(sym->name, ".cold"))
sym->cold = 1;
sym->pfunc = sym->cfunc = sym;
diff --git a/tools/objtool/include/objtool/elf.h b/tools/objtool/include/objtool/elf.h
index 60f844e43c5a2..21d8b825fd8f0 100644
--- a/tools/objtool/include/objtool/elf.h
+++ b/tools/objtool/include/objtool/elf.h
@@ -88,6 +88,7 @@ struct symbol {
u8 debug_checksum : 1;
u8 changed : 1;
u8 included : 1;
+ u8 klp : 1;
struct list_head pv_target;
struct reloc *relocs;
struct section *group_sec;
diff --git a/tools/objtool/include/objtool/objtool.h b/tools/objtool/include/objtool/objtool.h
index 7f70b41d1b8db..f7051bbe0bcb2 100644
--- a/tools/objtool/include/objtool/objtool.h
+++ b/tools/objtool/include/objtool/objtool.h
@@ -28,7 +28,7 @@ struct objtool_file {
struct list_head mcount_loc_list;
struct list_head endbr_list;
struct list_head call_list;
- bool ignore_unreachables, hints, rodata;
+ bool ignore_unreachables, hints, rodata, klp;
unsigned int nr_endbr;
unsigned int nr_endbr_int;
--
2.50.0In preparation for introducing klp-build, add a new CONFIG_KLP_BUILD
option. The initial version will only be supported on x86-64.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
arch/x86/Kconfig | 1 +
kernel/livepatch/Kconfig | 12 ++++++++++++
2 files changed, 13 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 19b1dbc8d5d26..986d31587e999 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -260,6 +260,7 @@ config X86
select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_KRETPROBES
select HAVE_RETHOOK
+ select HAVE_KLP_BUILD if X86_64
select HAVE_LIVEPATCH if X86_64
select HAVE_MIXED_BREAKPOINTS_REGS
select HAVE_MOD_ARCH_SPECIFIC
diff --git a/kernel/livepatch/Kconfig b/kernel/livepatch/Kconfig
index 53d51ed619a3d..4c0a9c18d0b25 100644
--- a/kernel/livepatch/Kconfig
+++ b/kernel/livepatch/Kconfig
@@ -18,3 +18,15 @@ config LIVEPATCH
module uses the interface provided by this option to register
a patch, causing calls to patched functions to be redirected
to new function code contained in the patch module.
+
+config HAVE_KLP_BUILD
+ bool
+ help
+ Arch supports klp-build
+
+config KLP_BUILD
+ def_bool y
+ depends on LIVEPATCH && HAVE_KLP_BUILD
+ select OBJTOOL
+ help
+ Enable klp-build support
--
2.50.0In preparation for klp-build, defer objtool validation for
CONFIG_KLP_BUILD kernels until the final pre-link archive (e.g.,
vmlinux.o, module-foo.o) is built. This will simplify the process of
generating livepatch modules.
Delayed objtool is generally preferred anyway, and is already standard
for IBT and LTO. Eventually the per-translation-unit mode will be
phased out.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/Makefile.lib | 2 +-
scripts/link-vmlinux.sh | 3 ++-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 15fee73e92895..28a1c08e3b221 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -197,7 +197,7 @@ objtool-args = $(objtool-args-y) \
$(if $(delay-objtool), --link) \
$(if $(part-of-module), --module)
-delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))
+delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT),$(CONFIG_KLP_BUILD))
cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool-args) $@)
cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 51367c2bfc21e..59f8752362926 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -60,7 +60,8 @@ vmlinux_link()
# skip output file argument
shift
- if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
+ if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT ||
+ is_enabled CONFIG_KLP_BUILD; then
# Use vmlinux.o instead of performing the slow LTO link again.
objs=vmlinux.o
libs=
--
2.50.0The __LINE__ macro creates challenges for binary diffing. When a .patch
file adds or removes lines, it shifts the line numbers for all code
below it.
This can cause the code generation of functions using __LINE__ to change
due to the line number constant being embedded in a MOV instruction,
despite there being no semantic difference.
Avoid such false positives by adding a fix-patch-lines script which can
be used to insert a #line directive in each patch hunk affecting the
line numbering. This script will be used by klp-build, which will be
introduced in a subsequent patch.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
MAINTAINERS | 1 +
scripts/livepatch/fix-patch-lines | 79 +++++++++++++++++++++++++++++++
2 files changed, 80 insertions(+)
create mode 100755 scripts/livepatch/fix-patch-lines
diff --git a/MAINTAINERS b/MAINTAINERS
index 605390cdfb75e..485042b545b3e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14225,6 +14225,7 @@ F: include/linux/livepatch*.h
F: kernel/livepatch/
F: kernel/module/livepatch.c
F: samples/livepatch/
+F: scripts/livepatch/
F: tools/testing/selftests/livepatch/
LLC (802.2)
diff --git a/scripts/livepatch/fix-patch-lines b/scripts/livepatch/fix-patch-lines
new file mode 100755
index 0000000000000..73c5e3dea46e1
--- /dev/null
+++ b/scripts/livepatch/fix-patch-lines
@@ -0,0 +1,79 @@
+#!/usr/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+#
+# Use #line directives to preserve original __LINE__ numbers across patches to
+# avoid unwanted compilation changes.
+
+BEGIN {
+ in_hunk = 0
+ skip = 0
+}
+
+/^--- / {
+ skip = $2 !~ /\.(c|h)$/
+ print
+ next
+}
+
+/^@@/ {
+ if (skip) {
+ print
+ next
+ }
+
+ in_hunk = 1
+
+ # for @@ -1,3 +1,4 @@:
+ # 1: line number in old file
+ # 3: how many lines the hunk covers in old file
+ # 1: line number in new file
+ # 4: how many lines the hunk covers in new file
+
+ match($0, /^@@ -([0-9]+)(,([0-9]+))? \+([0-9]+)(,([0-9]+))? @@/, m)
+
+ # Set 'cur' to the old file's line number at the start of the hunk. It
+ # gets incremented for every context line and every line removal, so
+ # that it always represents the old file's current line number.
+ cur = m[1]
+
+ # last = last line number of current hunk
+ last = cur + (m[3] ? m[3] : 1) - 1
+
+ need_line_directive = 0
+
+ print
+ next
+}
+
+{
+ if (skip || !in_hunk || $0 ~ /^\\ No newline at end of file/) {
+ print
+ next
+ }
+
+ # change line
+ if ($0 ~ /^[+-]/) {
+ # inject #line after this group of changes
+ need_line_directive = 1
+
+ if ($0 ~ /^-/)
+ cur++
+
+ print
+ next
+ }
+
+ # If this is the first context line after a group of changes, inject
+ # the #line directive to force the compiler to correct the line
+ # numbering to match the original file.
+ if (need_line_directive) {
+ print "+#line " cur
+ need_line_directive = 0
+ }
+
+ if (cur == last)
+ in_hunk = 0
+
+ cur++
+ print
+}
--
2.50.0Add a module initialization stub which can be linked with binary diff
objects to produce a livepatch module.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/livepatch/init.c | 108 +++++++++++++++++++++++++++++++++++++++
1 file changed, 108 insertions(+)
create mode 100644 scripts/livepatch/init.c
diff --git a/scripts/livepatch/init.c b/scripts/livepatch/init.c
new file mode 100644
index 0000000000000..2274d8f5a4826
--- /dev/null
+++ b/scripts/livepatch/init.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Init code for a livepatch kernel module
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/livepatch.h>
+
+extern struct klp_object_ext __start_klp_objects[];
+extern struct klp_object_ext __stop_klp_objects[];
+
+static struct klp_patch *patch;
+
+static int __init livepatch_mod_init(void)
+{
+ struct klp_object *objs;
+ unsigned int nr_objs;
+ int ret;
+
+ nr_objs = __stop_klp_objects - __start_klp_objects;
+
+ if (!nr_objs) {
+ pr_err("nothing to patch!\n");
+ ret = -EINVAL;
+ goto err;
+ }
+
+ patch = kzalloc(sizeof(*patch), GFP_KERNEL);
+ if (!patch) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ objs = kzalloc(sizeof(struct klp_object) * (nr_objs + 1), GFP_KERNEL);
+ if (!objs) {
+ ret = -ENOMEM;
+ goto err_free_patch;
+ }
+
+ for (int i = 0; i < nr_objs; i++) {
+ struct klp_object_ext *obj_ext = __start_klp_objects + i;
+ struct klp_func_ext *funcs_ext = obj_ext->funcs;
+ unsigned int nr_funcs = obj_ext->nr_funcs;
+ struct klp_func *funcs = objs[i].funcs;
+ struct klp_object *obj = objs + i;
+
+ funcs = kzalloc(sizeof(struct klp_func) * (nr_funcs + 1), GFP_KERNEL);
+ if (!funcs) {
+ ret = -ENOMEM;
+ for (int j = 0; j < i; j++)
+ kfree(objs[i].funcs);
+ goto err_free_objs;
+ }
+
+ for (int j = 0; j < nr_funcs; j++) {
+ funcs[j].old_name = funcs_ext[j].old_name;
+ funcs[j].new_func = funcs_ext[j].new_func;
+ funcs[j].old_sympos = funcs_ext[j].sympos;
+ }
+
+ obj->name = obj_ext->name;
+ obj->funcs = funcs;
+
+ memcpy(&obj->callbacks, &obj_ext->callbacks, sizeof(struct klp_callbacks));
+ }
+
+ patch->mod = THIS_MODULE;
+ patch->objs = objs;
+
+ /* TODO patch->states */
+
+#ifdef KLP_NO_REPLACE
+ patch->replace = false;
+#else
+ patch->replace = true;
+#endif
+
+ return klp_enable_patch(patch);
+
+err_free_objs:
+ kfree(objs);
+err_free_patch:
+ kfree(patch);
+err:
+ return ret;
+}
+
+static void __exit livepatch_mod_exit(void)
+{
+ unsigned int nr_objs;
+
+ nr_objs = __stop_klp_objects - __start_klp_objects;
+
+ for (int i = 0; i < nr_objs; i++)
+ kfree(patch->objs[i].funcs);
+
+ kfree(patch->objs);
+ kfree(patch);
+}
+
+module_init(livepatch_mod_init);
+module_exit(livepatch_mod_exit);
+MODULE_LICENSE("GPL");
+MODULE_INFO(livepatch, "Y");
+MODULE_DESCRIPTION("Livepatch module");
--
2.50.0Add a klp-build script which automates the generation of a livepatch
module from a source .patch file by performing the following steps:
- Builds an original kernel with -function-sections and
-fdata-sections, plus objtool function checksumming.
- Applies the .patch file and rebuilds the kernel using the same
options.
- Runs 'objtool klp diff' to detect changed functions and generate
intermediate binary diff objects.
- Builds a kernel module which links the diff objects with some
livepatch module init code (scripts/livepatch/init.c).
- Finalizes the livepatch module (aka work around linker wreckage)
using 'objtool klp post-link'.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/Makefile.lib | 1 +
scripts/livepatch/fix-patch-lines | 2 +-
scripts/livepatch/klp-build | 743 ++++++++++++++++++++++++++++++
tools/objtool/klp-diff.c | 6 +-
4 files changed, 749 insertions(+), 3 deletions(-)
create mode 100755 scripts/livepatch/klp-build
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 28a1c08e3b221..f4b33919ec371 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -173,6 +173,7 @@ ifdef CONFIG_OBJTOOL
objtool := $(objtree)/tools/objtool/objtool
+objtool-args-$(CONFIG_KLP_BUILD) += --checksum
objtool-args-$(CONFIG_HAVE_JUMP_LABEL_HACK) += --hacks=jump_label
objtool-args-$(CONFIG_HAVE_NOINSTR_HACK) += --hacks=noinstr
objtool-args-$(CONFIG_MITIGATION_CALL_DEPTH_TRACKING) += --hacks=skylake
diff --git a/scripts/livepatch/fix-patch-lines b/scripts/livepatch/fix-patch-lines
index 73c5e3dea46e1..fa7d4f6592e6b 100755
--- a/scripts/livepatch/fix-patch-lines
+++ b/scripts/livepatch/fix-patch-lines
@@ -23,7 +23,7 @@ BEGIN {
in_hunk = 1
- # for @@ -1,3 +1,4 @@:
+ # @@ -1,3 +1,4 @@:
# 1: line number in old file
# 3: how many lines the hunk covers in old file
# 1: line number in new file
diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
new file mode 100755
index 0000000000000..01ed0b66bfaff
--- /dev/null
+++ b/scripts/livepatch/klp-build
@@ -0,0 +1,743 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Build a livepatch module
+
+# shellcheck disable=SC1090,SC2155
+
+if (( BASH_VERSINFO[0] < 4 || \
+ (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] < 4) )); then
+ echo "error: this script requires bash 4.4+" >&2
+ exit 1
+fi
+
+set -o errexit
+set -o errtrace
+set -o pipefail
+set -o nounset
+
+# Allow doing 'cmd | mapfile -t array' instead of 'mapfile -t array < <(cmd)'.
+# This helps keep execution in pipes so pipefail+errexit can catch errors.
+shopt -s lastpipe
+
+unset SKIP_CLEANUP XTRACE
+
+REPLACE=1
+SHORT_CIRCUIT=0
+JOBS="$(getconf _NPROCESSORS_ONLN)"
+VERBOSE="-s"
+shopt -o xtrace | grep -q 'on' && XTRACE=1
+
+# Avoid removing the previous $TMP_DIR until args have been fully processed.
+KEEP_TMP=1
+
+SCRIPT="$(basename "$0")"
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+FIX_PATCH_LINES="$SCRIPT_DIR/fix-patch-lines"
+
+SRC="$(pwd)"
+OBJ="$(pwd)"
+
+CONFIG="$OBJ/.config"
+TMP_DIR="$OBJ/klp-tmp"
+
+ORIG_DIR="$TMP_DIR/orig"
+PATCHED_DIR="$TMP_DIR/patched"
+DIFF_DIR="$TMP_DIR/diff"
+KMOD_DIR="$TMP_DIR/kmod"
+
+STASH_DIR="$TMP_DIR/stash"
+TIMESTAMP="$TMP_DIR/timestamp"
+PATCH_TMP_DIR="$TMP_DIR/tmp"
+
+KLP_DIFF_LOG="$DIFF_DIR/diff.log"
+
+grep0() {
+ command grep "$@" || true
+}
+
+status() {
+ echo "$*"
+}
+
+warn() {
+ echo "error: $SCRIPT: $*" >&2
+}
+
+die() {
+ warn "$@"
+ exit 1
+}
+
+declare -a STASHED_FILES
+
+stash_file() {
+ local file="$1"
+ local rel_file="${file#"$SRC"/}"
+
+ [[ ! -e "$file" ]] && die "no file to stash: $file"
+
+ mkdir -p "$STASH_DIR/$(dirname "$rel_file")"
+ cp -f "$file" "$STASH_DIR/$rel_file"
+
+ STASHED_FILES+=("$rel_file")
+}
+
+restore_files() {
+ local file
+
+ for file in "${STASHED_FILES[@]}"; do
+ mv -f "$STASH_DIR/$file" "$SRC/$file" || warn "can't restore file: $file"
+ done
+
+ STASHED_FILES=()
+}
+
+cleanup() {
+ set +o nounset
+ revert_patches "--recount"
+ restore_files
+ [[ "$KEEP_TMP" -eq 0 ]] && rm -rf "$TMP_DIR"
+ return 0
+}
+
+trap_err() {
+ warn "line ${BASH_LINENO[0]}: '$BASH_COMMAND'"
+}
+
+trap cleanup EXIT INT TERM HUP
+trap trap_err ERR
+
+__usage() {
+ cat <<EOF
+Usage: $SCRIPT [OPTIONS] PATCH_FILE(s)
+Generate a livepatch module.
+
+Options:
+ -j, --jobs=<jobs> Build jobs to run simultaneously [default: $JOBS]
+ -o, --output=<file.ko> Output file [default: livepatch-<patch-name>.ko]
+ --no-replace Disable livepatch atomic replace
+ -v, --verbose Pass V=1 to kernel/module builds
+
+Advanced Options:
+ -S, --short-circuit=STEP Start at build step (requires prior --keep-tmp)
+ 1|orig Build original kernel (default)
+ 2|patched Build patched kernel
+ 3|diff Diff objects
+ 4|kmod Build patch module
+ -T, --keep-tmp Preserve tmp dir on exit
+
+EOF
+}
+
+usage() {
+ __usage >&2
+}
+
+process_args() {
+ local keep_tmp=0
+ local short
+ local long
+ local args
+
+ short="hj:o:vS:T"
+ long="help,jobs:,output:,no-replace,verbose,short-circuit:,keep-tmp"
+
+ args=$(getopt --options "$short" --longoptions "$long" -- "$@") || {
+ echo; usage; exit
+ }
+ eval set -- "$args"
+
+ while true; do
+ case "$1" in
+ -h | --help)
+ usage
+ exit 0
+ ;;
+ -j | --jobs)
+ JOBS="$2"
+ shift 2
+ ;;
+ -o | --output)
+ [[ "$2" != *.ko ]] && die "output filename should end with .ko"
+ OUTFILE="$2"
+ NAME="$(basename "$OUTFILE")"
+ NAME="${NAME%.ko}"
+ NAME="$(module_name_string "$NAME")"
+ shift 2
+ ;;
+ --no-replace)
+ REPLACE=0
+ shift
+ ;;
+ -v | --verbose)
+ VERBOSE="V=1"
+ shift
+ ;;
+ -S | --short-circuit)
+ [[ ! -d "$TMP_DIR" ]] && die "--short-circuit requires preserved klp-tmp dir"
+ keep_tmp=1
+ case "$2" in
+ 1 | orig) SHORT_CIRCUIT=1; ;;
+ 2 | patched) SHORT_CIRCUIT=2; ;;
+ 3 | diff) SHORT_CIRCUIT=3; ;;
+ 4 | mod) SHORT_CIRCUIT=4; ;;
+ *) die "invalid short-circuit step '$2'" ;;
+ esac
+ shift 2
+ ;;
+ -T | --keep-tmp)
+ keep_tmp=1
+ shift
+ ;;
+ --)
+ shift
+ break
+ ;;
+ *)
+ usage
+ exit 1
+ ;;
+ esac
+ done
+
+ if [[ $# -eq 0 ]]; then
+ usage
+ exit 1
+ fi
+
+ KEEP_TMP="$keep_tmp"
+ PATCHES=("$@")
+}
+
+# temporarily disable xtrace for especially verbose code
+xtrace_save() {
+ [[ -v XTRACE ]] && set +x
+ return 0
+}
+
+xtrace_restore() {
+ [[ -v XTRACE ]] && set -x
+ return 0
+}
+
+validate_config() {
+ xtrace_save "reading .config"
+ source "$CONFIG" || die "no .config file in $(dirname "$CONFIG")"
+ xtrace_restore
+
+ [[ -v CONFIG_LIVEPATCH ]] || \
+ die "CONFIG_LIVEPATCH not enabled"
+
+ [[ -v CONFIG_KLP_BUILD ]] || \
+ die "CONFIG_KLP_BUILD not enabled"
+
+ [[ -v CONFIG_GCC_PLUGIN_LATENT_ENTROPY ]] && \
+ die "kernel option 'CONFIG_GCC_PLUGIN_LATENT_ENTROPY' not supported"
+
+ [[ -v CONFIG_GCC_PLUGIN_RANDSTRUCT ]] && \
+ die "kernel option 'CONFIG_GCC_PLUGIN_RANDSTRUCT' not supported"
+
+ return 0
+}
+
+# Only allow alphanumerics and '_' and '-' in the module name. Everything else
+# is replaced with '-'. Also truncate to 55 chars so the full name + NUL
+# terminator fits in the kernel's 56-byte module name array.
+module_name_string() {
+ echo "${1//[^a-zA-Z0-9_-]/-}" | cut -c 1-55
+}
+
+# If the module name wasn't specified on the cmdline with --output, give it a
+# name based on the patch name.
+set_module_name() {
+ [[ -v NAME ]] && return 0
+
+ if [[ "${#PATCHES[@]}" -eq 1 ]]; then
+ NAME="$(basename "${PATCHES[0]}")"
+ NAME="${NAME%.*}"
+ else
+ NAME="patch"
+ fi
+
+ NAME="livepatch-$NAME"
+ NAME="$(module_name_string "$NAME")"
+
+ OUTFILE="$NAME.ko"
+}
+
+# Hardcode the value printed by the localversion script to prevent patch
+# application from appending it with '+' due to a dirty git working tree.
+set_kernelversion() {
+ local file="$SRC/scripts/setlocalversion"
+ local localversion
+
+ stash_file "$file"
+
+ localversion="$(cd "$SRC" && make --no-print-directory kernelversion)"
+ localversion="$(cd "$SRC" && KERNELVERSION="$localversion" ./scripts/setlocalversion)"
+ [[ -z "$localversion" ]] && die "setlocalversion failed"
+
+ sed -i "2i echo $localversion; exit 0" scripts/setlocalversion
+}
+
+get_patch_files() {
+ local patch="$1"
+
+ grep0 -E '^(--- |\+\+\+ )' "$patch" \
+ | gawk '{print $2}' \
+ | sed 's|^[^/]*/||' \
+ | sort -u
+}
+
+# Make sure git re-stats the changed files
+git_refresh() {
+ local patch="$1"
+ local files=()
+
+ [[ ! -e "$SRC/.git" ]] && return
+
+ get_patch_files "$patch" | mapfile -t files
+
+ (
+ cd "$SRC"
+ git update-index -q --refresh -- "${files[@]}"
+ )
+}
+
+check_unsupported_patches() {
+ local patch
+
+ for patch in "${PATCHES[@]}"; do
+ local files=()
+
+ get_patch_files "$patch" | mapfile -t files
+
+ for file in "${files[@]}"; do
+ case "$file" in
+ lib/*|*.S)
+ die "unsupported patch to $file"
+ ;;
+ esac
+ done
+ done
+}
+
+apply_patch() {
+ local patch="$1"
+ shift
+ local extra_args=("$@")
+
+ [[ ! -f "$patch" ]] && die "$patch doesn't exist"
+
+ (
+ cd "$SRC"
+
+ # The sed strips the version signature from 'git format-patch',
+ # otherwise 'git apply --recount' warns.
+ sed -n '/^-- /q;p' "$patch" |
+ git apply "${extra_args[@]}"
+ )
+
+ APPLIED_PATCHES+=("$patch")
+}
+
+revert_patch() {
+ local patch="$1"
+ shift
+ local extra_args=("$@")
+ local tmp=()
+
+ (
+ cd "$SRC"
+
+ sed -n '/^-- /q;p' "$patch" |
+ git apply --reverse "${extra_args[@]}"
+ )
+ git_refresh "$patch"
+
+ for p in "${APPLIED_PATCHES[@]}"; do
+ [[ "$p" == "$patch" ]] && continue
+ tmp+=("$p")
+ done
+
+ APPLIED_PATCHES=("${tmp[@]}")
+}
+
+apply_patches() {
+ local patch
+
+ for patch in "${PATCHES[@]}"; do
+ apply_patch "$patch"
+ done
+}
+
+revert_patches() {
+ local extra_args=("$@")
+ local patches=("${APPLIED_PATCHES[@]}")
+
+ for (( i=${#patches[@]}-1 ; i>=0 ; i-- )) ; do
+ revert_patch "${patches[$i]}" "${extra_args[@]}"
+ done
+
+ APPLIED_PATCHES=()
+}
+
+validate_patches() {
+ check_unsupported_patches
+ apply_patches
+ revert_patches
+}
+
+do_init() {
+ # We're not yet smart enough to handle anything other than in-tree
+ # builds in pwd.
+ [[ ! "$SRC" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
+ [[ ! "$OBJ" -ef "$SCRIPT_DIR/../.." ]] && die "please run from the kernel root directory"
+
+ (( SHORT_CIRCUIT <= 1 )) && rm -rf "$TMP_DIR"
+ mkdir -p "$TMP_DIR"
+
+ APPLIED_PATCHES=()
+
+ [[ -x "$FIX_PATCH_LINES" ]] || die "can't find fix-patch-lines"
+
+ validate_config
+ set_module_name
+ set_kernelversion
+}
+
+# Refresh the patch hunk headers, specifically the line numbers and counts.
+refresh_patch() {
+ local patch="$1"
+ local tmpdir="$PATCH_TMP_DIR"
+ local files=()
+
+ rm -rf "$tmpdir"
+ mkdir -p "$tmpdir/a"
+ mkdir -p "$tmpdir/b"
+
+ # Get all source files affected by the patch
+ get_patch_files "$patch" | mapfile -t files
+
+ # Copy orig source files to 'a'
+ ( cd "$SRC" && echo "${files[@]}" | xargs cp --parents --target-directory="$tmpdir/a" )
+
+ # Copy patched source files to 'b'
+ apply_patch "$patch" --recount
+ ( cd "$SRC" && echo "${files[@]}" | xargs cp --parents --target-directory="$tmpdir/b" )
+ revert_patch "$patch" --recount
+
+ # Diff 'a' and 'b' to make a clean patch
+ ( cd "$tmpdir" && git diff --no-index --no-prefix a b > "$patch" ) || true
+}
+
+# Copy the patches to a temporary directory, fix their lines so as not to
+# affect the __LINE__ macro for otherwise unchanged functions further down the
+# file, and update $PATCHES to point to the fixed patches.
+fix_patches() {
+ local idx
+ local i
+
+ rm -f "$TMP_DIR"/*.patch
+
+ idx=0001
+ for i in "${!PATCHES[@]}"; do
+ local old_patch="${PATCHES[$i]}"
+ local tmp_patch="$TMP_DIR/tmp.patch"
+ local patch="${PATCHES[$i]}"
+ local new_patch
+
+ new_patch="$TMP_DIR/$idx-fixed-$(basename "$patch")"
+
+ cp -f "$old_patch" "$tmp_patch"
+ refresh_patch "$tmp_patch"
+ "$FIX_PATCH_LINES" "$tmp_patch" > "$new_patch"
+ refresh_patch "$new_patch"
+
+ PATCHES[i]="$new_patch"
+
+ rm -f "$tmp_patch"
+ idx=$(printf "%04d" $(( 10#$idx + 1 )))
+ done
+}
+
+clean_kernel() {
+ local cmd=()
+
+ cmd=("make")
+ cmd+=("--silent")
+ cmd+=("-j$JOBS")
+ cmd+=("clean")
+
+ (
+ cd "$SRC"
+ "${cmd[@]}"
+ )
+}
+
+build_kernel() {
+ local log="$TMP_DIR/build.log"
+ local cmd=()
+
+ cmd=("make")
+
+ # When a patch to a kernel module references a newly created unexported
+ # symbol which lives in vmlinux or another kernel module, the patched
+ # kernel build fails with the following error:
+ #
+ # ERROR: modpost: "klp_string" [fs/xfs/xfs.ko] undefined!
+ #
+ # The undefined symbols are working as designed in that case. They get
+ # resolved later when the livepatch module build link pulls all the
+ # disparate objects together into the same kernel module.
+ #
+ # It would be good to have a way to tell modpost to skip checking for
+ # undefined symbols altogether. For now, just convert the error to a
+ # warning with KBUILD_MODPOST_WARN, and grep out the warning to avoid
+ # confusing the user.
+ #
+ cmd+=("KBUILD_MODPOST_WARN=1")
+
+ cmd+=("$VERBOSE")
+ cmd+=("-j$JOBS")
+ cmd+=("KCFLAGS=-ffunction-sections -fdata-sections")
+ cmd+=("vmlinux")
+ cmd+=("modules")
+
+ (
+ cd "$SRC"
+ "${cmd[@]}" \
+ 1> >(tee -a "$log") \
+ 2> >(tee -a "$log" | grep0 -v "modpost.*undefined!" >&2)
+ )
+}
+
+find_objects() {
+ local opts=("$@")
+
+ # Find root-level vmlinux.o and non-root-level .ko files,
+ # excluding klp-tmp/ and .git/
+ find "$OBJ" \( -path "$TMP_DIR" -o -path "$OBJ/.git" -o -regex "$OBJ/[^/][^/]*\.ko" \) -prune -o \
+ -type f "${opts[@]}" \
+ \( -name "*.ko" -o -path "$OBJ/vmlinux.o" \) \
+ -printf '%P\n'
+}
+
+# Copy all .o archives to $ORIG_DIR
+copy_orig_objects() {
+ local files=()
+
+ rm -rf "$ORIG_DIR"
+ mkdir -p "$ORIG_DIR"
+
+ find_objects | mapfile -t files
+
+ xtrace_save "copying orig objects"
+ for _file in "${files[@]}"; do
+ local rel_file="${_file/.ko/.o}"
+ local file="$OBJ/$rel_file"
+ local file_dir="$(dirname "$file")"
+ local orig_file="$ORIG_DIR/$rel_file"
+ local orig_dir="$(dirname "$orig_file")"
+ local cmd_file="$file_dir/.$(basename "$file").cmd"
+
+ [[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
+
+ mkdir -p "$orig_dir"
+ cp -f "$file" "$orig_dir"
+ [[ -e "$cmd_file" ]] && cp -f "$cmd_file" "$orig_dir"
+ done
+ xtrace_restore
+
+ mv -f "$TMP_DIR/build.log" "$ORIG_DIR"
+ touch "$TIMESTAMP"
+}
+
+# Copy all changed objects to $PATCHED_DIR
+copy_patched_objects() {
+ local files=()
+ local opts=()
+ local found=0
+
+ rm -rf "$PATCHED_DIR"
+ mkdir -p "$PATCHED_DIR"
+
+ # Note this doesn't work with some configs, thus the 'cmp' below.
+ opts=("-newer")
+ opts+=("$TIMESTAMP")
+
+ find_objects "${opts[@]}" | mapfile -t files
+
+ xtrace_save "copying changed objects"
+ for _file in "${files[@]}"; do
+ local rel_file="${_file/.ko/.o}"
+ local file="$OBJ/$rel_file"
+ local orig_file="$ORIG_DIR/$rel_file"
+ local patched_file="$PATCHED_DIR/$rel_file"
+ local patched_dir="$(dirname "$patched_file")"
+
+ [[ ! -f "$file" ]] && die "missing $(basename "$file") for $_file"
+
+ cmp -s "$orig_file" "$file" && continue
+
+ mkdir -p "$patched_dir"
+ cp -f "$file" "$patched_dir"
+ found=1
+ done
+ xtrace_restore
+
+ (( found == 0 )) && die "no changes detected"
+
+ mv -f "$TMP_DIR/build.log" "$PATCHED_DIR"
+}
+
+# Diff changed objects, writing output object to $DIFF_DIR
+diff_objects() {
+ local log="$KLP_DIFF_LOG"
+ local files=()
+
+ rm -rf "$DIFF_DIR"
+ mkdir -p "$DIFF_DIR"
+
+ find "$PATCHED_DIR" -type f -name "*.o" | mapfile -t files
+ [[ ${#files[@]} -eq 0 ]] && die "no changes detected"
+
+ # Diff all changed objects
+ for file in "${files[@]}"; do
+ local rel_file="${file#"$PATCHED_DIR"/}"
+ local orig_file="$rel_file"
+ local patched_file="$PATCHED_DIR/$rel_file"
+ local out_file="$DIFF_DIR/$rel_file"
+ local cmd=()
+
+ mkdir -p "$(dirname "$out_file")"
+
+ cmd=("$SRC/tools/objtool/objtool")
+ cmd+=("klp")
+ cmd+=("diff")
+ cmd+=("$orig_file")
+ cmd+=("$patched_file")
+ cmd+=("$out_file")
+
+ (
+ cd "$ORIG_DIR"
+ "${cmd[@]}" \
+ 1> >(tee -a "$log") \
+ 2> >(tee -a "$log" >&2) || \
+ die "objtool klp diff failed"
+ )
+ done
+}
+
+# Build and post-process livepatch module in $KMOD_DIR
+build_patch_module() {
+ local makefile="$KMOD_DIR/Kbuild"
+ local log="$KMOD_DIR/build.log"
+ local kmod_file
+ local cflags=()
+ local files=()
+ local cmd=()
+
+ rm -rf "$KMOD_DIR"
+ mkdir -p "$KMOD_DIR"
+
+ cp -f "$SRC/scripts/livepatch/init.c" "$KMOD_DIR"
+
+ echo "obj-m := $NAME.o" > "$makefile"
+ echo -n "$NAME-y := init.o" >> "$makefile"
+
+ find "$DIFF_DIR" -type f -name "*.o" | mapfile -t files
+ [[ ${#files[@]} -eq 0 ]] && die "no changes detected"
+
+ for file in "${files[@]}"; do
+ local rel_file="${file#"$DIFF_DIR"/}"
+ local orig_file="$ORIG_DIR/$rel_file"
+ local orig_dir="$(dirname "$orig_file")"
+ local kmod_file="$KMOD_DIR/$rel_file"
+ local kmod_dir="$(dirname "$kmod_file")"
+ local cmd_file="$orig_dir/.$(basename "$file").cmd"
+
+ mkdir -p "$kmod_dir"
+ cp -f "$file" "$kmod_dir"
+ [[ -e "$cmd_file" ]] && cp -f "$cmd_file" "$kmod_dir"
+
+ # Tell kbuild this is a prebuilt object
+ cp -f "$file" "${kmod_file}_shipped"
+
+ echo -n " $rel_file" >> "$makefile"
+ done
+
+ echo >> "$makefile"
+
+ cflags=("-ffunction-sections")
+ cflags+=("-fdata-sections")
+ [[ $REPLACE -eq 0 ]] && cflags+=("-DKLP_NO_REPLACE")
+
+ cmd=("make")
+ cmd+=("$VERBOSE")
+ cmd+=("-j$JOBS")
+ cmd+=("--directory=.")
+ cmd+=("M=$KMOD_DIR")
+ cmd+=("KCFLAGS=${cflags[*]}")
+
+ # Build a "normal" kernel module with init.c and the diffed objects
+ (
+ cd "$SRC"
+ "${cmd[@]}" \
+ 1> >(tee -a "$log") \
+ 2> >(tee -a "$log" >&2)
+ )
+
+ kmod_file="$KMOD_DIR/$NAME.ko"
+
+ # Save off the intermediate binary for debugging
+ cp -f "$kmod_file" "$kmod_file.orig"
+
+ # Work around issue where slight .config change makes corrupt BTF
+ objcopy --remove-section=.BTF "$kmod_file"
+
+ # Fix (and work around) linker wreckage for klp syms / relocs
+ "$SRC/tools/objtool/objtool" klp post-link "$kmod_file" || die "objtool klp post-link failed"
+
+ cp -f "$kmod_file" "$OUTFILE"
+}
+
+
+################################################################################
+
+process_args "$@"
+do_init
+
+if (( SHORT_CIRCUIT <= 1 )); then
+ status "Validating patch(es)"
+ validate_patches
+ status "Building original kernel"
+ clean_kernel
+ build_kernel
+ status "Copying original object files"
+ copy_orig_objects
+fi
+
+if (( SHORT_CIRCUIT <= 2 )); then
+ status "Fixing patch(es)"
+ fix_patches
+ apply_patches
+ status "Building patched kernel"
+ build_kernel
+ revert_patches
+ status "Copying patched object files"
+ copy_patched_objects
+fi
+
+if (( SHORT_CIRCUIT <= 3 )); then
+ status "Diffing objects"
+ diff_objects
+fi
+
+if (( SHORT_CIRCUIT <= 4 )); then
+ status "Building patch module: $OUTFILE"
+ build_patch_module
+fi
+
+status "SUCCESS"
diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
index 817d44394a78c..4d1f9e9977eb9 100644
--- a/tools/objtool/klp-diff.c
+++ b/tools/objtool/klp-diff.c
@@ -241,10 +241,12 @@ static struct symbol *next_file_symbol(struct elf *elf, struct symbol *sym)
static bool is_uncorrelated_static_local(struct symbol *sym)
{
static const char * const vars[] = {
- "__key.",
- "__warned.",
"__already_done.",
"__func__.",
+ "__key.",
+ "__warned.",
+ "_entry.",
+ "_entry_ptr.",
"_rs.",
"descriptor.",
"CSWTCH.",
--
2.50.0Add a --debug option which gets passed to "objtool klp diff" to enable
debug output related to cloning decisions.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/livepatch/klp-build | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 01ed0b66bfaff..28ee259ce5f6e 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -20,7 +20,7 @@ set -o nounset
# This helps keep execution in pipes so pipefail+errexit can catch errors.
shopt -s lastpipe
-unset SKIP_CLEANUP XTRACE
+unset DEBUG_CLONE SKIP_CLEANUP XTRACE
REPLACE=1
SHORT_CIRCUIT=0
@@ -120,6 +120,7 @@ Options:
-v, --verbose Pass V=1 to kernel/module builds
Advanced Options:
+ -d, --debug Show symbol/reloc cloning decisions
-S, --short-circuit=STEP Start at build step (requires prior --keep-tmp)
1|orig Build original kernel (default)
2|patched Build patched kernel
@@ -140,8 +141,8 @@ process_args() {
local long
local args
- short="hj:o:vS:T"
- long="help,jobs:,output:,no-replace,verbose,short-circuit:,keep-tmp"
+ short="hj:o:vdS:T"
+ long="help,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp"
args=$(getopt --options "$short" --longoptions "$long" -- "$@") || {
echo; usage; exit
@@ -174,6 +175,11 @@ process_args() {
VERBOSE="V=1"
shift
;;
+ -d | --debug)
+ DEBUG_CLONE=1
+ keep_tmp=1
+ shift
+ ;;
-S | --short-circuit)
[[ ! -d "$TMP_DIR" ]] && die "--short-circuit requires preserved klp-tmp dir"
keep_tmp=1
@@ -596,6 +602,7 @@ copy_patched_objects() {
diff_objects() {
local log="$KLP_DIFF_LOG"
local files=()
+ local opts=()
rm -rf "$DIFF_DIR"
mkdir -p "$DIFF_DIR"
@@ -603,6 +610,8 @@ diff_objects() {
find "$PATCHED_DIR" -type f -name "*.o" | mapfile -t files
[[ ${#files[@]} -eq 0 ]] && die "no changes detected"
+ [[ -v DEBUG_CLONE ]] && opts=("--debug")
+
# Diff all changed objects
for file in "${files[@]}"; do
local rel_file="${file#"$PATCHED_DIR"/}"
@@ -616,6 +625,7 @@ diff_objects() {
cmd=("$SRC/tools/objtool/objtool")
cmd+=("klp")
cmd+=("diff")
+ (( ${#opts[@]} > 0 )) && cmd+=("${opts[@]}")
cmd+=("$orig_file")
cmd+=("$patched_file")
cmd+=("$out_file")
--
2.50.0Add a --show-first-changed option to identify where changed functions
begin to diverge:
- Parse 'objtool klp diff' output to find changed functions.
- Run objtool again on each object with --debug-checksum=<funcs>.
- Diff the per-instruction checksum debug output to locate the first
differing instruction.
This can be useful for quickly determining where and why a function
changed.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
scripts/livepatch/klp-build | 82 +++++++++++++++++++++++++++++++++++--
1 file changed, 78 insertions(+), 4 deletions(-)
diff --git a/scripts/livepatch/klp-build b/scripts/livepatch/klp-build
index 28ee259ce5f6e..881e052e7faef 100755
--- a/scripts/livepatch/klp-build
+++ b/scripts/livepatch/klp-build
@@ -20,7 +20,7 @@ set -o nounset
# This helps keep execution in pipes so pipefail+errexit can catch errors.
shopt -s lastpipe
-unset DEBUG_CLONE SKIP_CLEANUP XTRACE
+unset DEBUG_CLONE DIFF_CHECKSUM SKIP_CLEANUP XTRACE
REPLACE=1
SHORT_CIRCUIT=0
@@ -114,6 +114,7 @@ Usage: $SCRIPT [OPTIONS] PATCH_FILE(s)
Generate a livepatch module.
Options:
+ -f, --show-first-changed Show address of first changed instruction
-j, --jobs=<jobs> Build jobs to run simultaneously [default: $JOBS]
-o, --output=<file.ko> Output file [default: livepatch-<patch-name>.ko]
--no-replace Disable livepatch atomic replace
@@ -141,8 +142,8 @@ process_args() {
local long
local args
- short="hj:o:vdS:T"
- long="help,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp"
+ short="hfj:o:vdS:T"
+ long="help,show-first-changed,jobs:,output:,no-replace,verbose,debug,short-circuit:,keep-tmp"
args=$(getopt --options "$short" --longoptions "$long" -- "$@") || {
echo; usage; exit
@@ -155,6 +156,10 @@ process_args() {
usage
exit 0
;;
+ -f | --show-first-changed)
+ DIFF_CHECKSUM=1
+ shift
+ ;;
-j | --jobs)
JOBS="$2"
shift 2
@@ -618,6 +623,7 @@ diff_objects() {
local orig_file="$rel_file"
local patched_file="$PATCHED_DIR/$rel_file"
local out_file="$DIFF_DIR/$rel_file"
+ local filter=()
local cmd=()
mkdir -p "$(dirname "$out_file")"
@@ -630,16 +636,80 @@ diff_objects() {
cmd+=("$patched_file")
cmd+=("$out_file")
+ if [[ -v DIFF_CHECKSUM ]]; then
+ filter=("grep0")
+ filter+=("-Ev")
+ filter+=("DEBUG: .*checksum: ")
+ else
+ filter=("cat")
+ fi
+
(
cd "$ORIG_DIR"
"${cmd[@]}" \
1> >(tee -a "$log") \
- 2> >(tee -a "$log" >&2) || \
+ 2> >(tee -a "$log" | "${filter[@]}" >&2) || \
die "objtool klp diff failed"
)
done
}
+# For each changed object, run objtool with --debug-checksum to get the
+# per-instruction checksums, and then diff those to find the first changed
+# instruction for each function.
+diff_checksums() {
+ local orig_log="$ORIG_DIR/checksum.log"
+ local patched_log="$PATCHED_DIR/checksum.log"
+ local -A funcs
+ local cmd=()
+ local line
+ local file
+ local func
+
+ gawk '/\.o: changed function: / {
+ sub(/:$/, "", $1)
+ print $1, $NF
+ }' "$KLP_DIFF_LOG" | mapfile -t lines
+
+ for line in "${lines[@]}"; do
+ read -r file func <<< "$line"
+ if [[ ! -v funcs["$file"] ]]; then
+ funcs["$file"]="$func"
+ else
+ funcs["$file"]+=" $func"
+ fi
+ done
+
+ cmd=("$SRC/tools/objtool/objtool")
+ cmd+=("--checksum")
+ cmd+=("--link")
+ cmd+=("--dry-run")
+
+ for file in "${!funcs[@]}"; do
+ local opt="--debug-checksum=${funcs[$file]// /,}"
+
+ (
+ cd "$ORIG_DIR"
+ "${cmd[@]}" "$opt" "$file" &> "$orig_log" || \
+ ( cat "$orig_log" >&2; die "objtool --debug-checksum failed" )
+
+ cd "$PATCHED_DIR"
+ "${cmd[@]}" "$opt" "$file" &> "$patched_log" || \
+ ( cat "$patched_log" >&2; die "objtool --debug-checksum failed" )
+ )
+
+ for func in ${funcs[$file]}; do
+ diff <( grep0 -E "^DEBUG: .*checksum: $func " "$orig_log" | sed "s|$ORIG_DIR/||") \
+ <( grep0 -E "^DEBUG: .*checksum: $func " "$patched_log" | sed "s|$PATCHED_DIR/||") \
+ | gawk '/^< DEBUG: / {
+ gsub(/:/, "")
+ printf "%s: %s: %s\n", $3, $5, $6
+ exit
+ }' || true
+ done
+ done
+}
+
# Build and post-process livepatch module in $KMOD_DIR
build_patch_module() {
local makefile="$KMOD_DIR/Kbuild"
@@ -743,6 +813,10 @@ fi
if (( SHORT_CIRCUIT <= 3 )); then
status "Diffing objects"
diff_objects
+ if [[ -v DIFF_CHECKSUM ]]; then
+ status "Finding first changed instructions"
+ diff_checksums
+ fi
fi
if (( SHORT_CIRCUIT <= 4 )); then
--
2.50.0Add some helper macros which can be used by livepatch source .patch
files to register callbacks, convert static calls to regular calls where
needed, and patch syscalls.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/livepatch_helpers.h | 77 +++++++++++++++++++++++++++++++
1 file changed, 77 insertions(+)
create mode 100644 include/linux/livepatch_helpers.h
diff --git a/include/linux/livepatch_helpers.h b/include/linux/livepatch_helpers.h
new file mode 100644
index 0000000000000..99d68d0773fa8
--- /dev/null
+++ b/include/linux/livepatch_helpers.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_LIVEPATCH_HELPERS_H
+#define _LINUX_LIVEPATCH_HELPERS_H
+
+/*
+ * Interfaces for use by livepatch patches
+ */
+
+#include <linux/syscalls.h>
+#include <linux/livepatch.h>
+
+#ifdef MODULE
+#define KLP_OBJNAME __KBUILD_MODNAME
+#else
+#define KLP_OBJNAME vmlinux
+#endif
+
+/* Livepatch callback registration */
+
+#define KLP_CALLBACK_PTRS ".discard.klp_callback_ptrs"
+
+#define KLP_PRE_PATCH_CALLBACK(func) \
+ klp_pre_patch_t __used __section(KLP_CALLBACK_PTRS) \
+ __PASTE(__KLP_PRE_PATCH_PREFIX, KLP_OBJNAME) = func
+
+#define KLP_POST_PATCH_CALLBACK(func) \
+ klp_post_patch_t __used __section(KLP_CALLBACK_PTRS) \
+ __PASTE(__KLP_POST_PATCH_PREFIX, KLP_OBJNAME) = func
+
+#define KLP_PRE_UNPATCH_CALLBACK(func) \
+ klp_pre_unpatch_t __used __section(KLP_CALLBACK_PTRS) \
+ __PASTE(__KLP_PRE_UNPATCH_PREFIX, KLP_OBJNAME) = func
+
+#define KLP_POST_UNPATCH_CALLBACK(func) \
+ klp_post_unpatch_t __used __section(KLP_CALLBACK_PTRS) \
+ __PASTE(__KLP_POST_UNPATCH_PREFIX, KLP_OBJNAME) = func
+
+/*
+ * Replace static_call() usage with this macro when create-diff-object
+ * recommends it due to the original static call key living in a module.
+ *
+ * This converts the static call to a regular indirect call.
+ */
+#define KLP_STATIC_CALL(name) \
+ ((typeof(STATIC_CALL_TRAMP(name))*)(STATIC_CALL_KEY(name).func))
+
+/* Syscall patching */
+
+#define KLP_SYSCALL_DEFINE1(name, ...) KLP_SYSCALL_DEFINEx(1, _##name, __VA_ARGS__)
+#define KLP_SYSCALL_DEFINE2(name, ...) KLP_SYSCALL_DEFINEx(2, _##name, __VA_ARGS__)
+#define KLP_SYSCALL_DEFINE3(name, ...) KLP_SYSCALL_DEFINEx(3, _##name, __VA_ARGS__)
+#define KLP_SYSCALL_DEFINE4(name, ...) KLP_SYSCALL_DEFINEx(4, _##name, __VA_ARGS__)
+#define KLP_SYSCALL_DEFINE5(name, ...) KLP_SYSCALL_DEFINEx(5, _##name, __VA_ARGS__)
+#define KLP_SYSCALL_DEFINE6(name, ...) KLP_SYSCALL_DEFINEx(6, _##name, __VA_ARGS__)
+
+#define KLP_SYSCALL_DEFINEx(x, sname, ...) \
+ __KLP_SYSCALL_DEFINEx(x, sname, __VA_ARGS__)
+
+#ifdef CONFIG_X86_64
+// TODO move this to arch/x86/include/asm/syscall_wrapper.h and share code
+#define __KLP_SYSCALL_DEFINEx(x, name, ...) \
+ static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ static inline long __klp_do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
+ __X64_SYS_STUBx(x, name, __VA_ARGS__) \
+ __IA32_SYS_STUBx(x, name, __VA_ARGS__) \
+ static long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ { \
+ long ret = __klp_do_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\
+ __MAP(x,__SC_TEST,__VA_ARGS__); \
+ __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
+ return ret; \
+ } \
+ static inline long __klp_do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+
+#endif
+
+#endif /* _LINUX_LIVEPATCH_HELPERS_H */
--
2.50.0© 2016 - 2025 Red Hat, Inc.