Improve the readability and compactness of the objtool annotations.
This makes it easier to see them and differentiate from other code.
Before:
-------
911:
.pushsection .discard.annotate_insn,"M",@progbits,8
.long 911b - .
.long 1
.popsection
After:
------
# <ANNOTATE_NOENDBR>
911: .pushsection .discard.annotate_insn,"M",@progbits,8; .long 911b - .; .long 1; .popsection
# </ANNOTATE_NOENDBR>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
include/linux/objtool.h | 97 ++++++++++++++++++++---------------------
1 file changed, 47 insertions(+), 50 deletions(-)
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 366ad004d794..66549603147e 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -8,19 +8,31 @@
#include <asm/asm.h>
+#define __UNWIND_HINT(label, type, sp_reg, sp_offset, signal) \
+ .pushsection .discard.unwind_hints; \
+ /* struct unwind_hint */ \
+ .long label - .; \
+ .short sp_offset; \
+ .byte sp_reg; \
+ .byte type; \
+ .byte signal; \
+ .balign 4; \
+ .popsection
+
+#define __ASM_ANNOTATE(label, type) \
+ .pushsection .discard.annotate_insn,"M",@progbits,8; \
+ .long label - .; \
+ .long type; \
+ .popsection
+
#ifndef __ASSEMBLY__
-#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
- "987: \n\t" \
- ".pushsection .discard.unwind_hints\n\t" \
- /* struct unwind_hint */ \
- ".long 987b - .\n\t" \
- ".short " __stringify(sp_offset) "\n\t" \
- ".byte " __stringify(sp_reg) "\n\t" \
- ".byte " __stringify(type) "\n\t" \
- ".byte " __stringify(signal) "\n\t" \
- ".balign 4 \n\t" \
- ".popsection\n\t"
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal) \
+ "\n# <UNWIND_HINT>\n" \
+ "987: " \
+ __stringify(__UNWIND_HINT(987b, type, sp_reg, \
+ sp_offset, signal)) \
+ "\n# </UNWIND_HINT>\n\t"
/*
* This macro marks the given function's stack frame as "non-standard", which
@@ -45,23 +57,18 @@
#define STACK_FRAME_NON_STANDARD_FP(func)
#endif
-#define ASM_REACHABLE \
- "998:\n\t" \
- ".pushsection .discard.reachable\n\t" \
- ".long 998b\n\t" \
- ".popsection\n\t"
-
#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)
+ "\n# <ANNOTATE_" __stringify(type) ">\n" \
+ "911:\t" \
+ __stringify(__ASM_ANNOTATE(911b, __PASTE(ANNOTYPE_, type))) \
+ "\n# </ANNOTATE_" __stringify(type) ">\n\t"
+
+#define ASM_ANNOTATE_LABEL(label, type) \
+ "\n# BEGIN ANNOTATE_" __stringify(type) "\n" \
+ __stringify(__ASM_ANNOTATE(label, __PASTE(ANNOTYPE_, type))) \
+ "\n# </ANNOTATE_" __stringify(type) "\n\t"
#else /* __ASSEMBLY__ */
@@ -88,15 +95,7 @@
*/
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.Lhere_\@:
- .pushsection .discard.unwind_hints
- /* struct unwind_hint */
- .long .Lhere_\@ - .
- .short \sp_offset
- .byte \sp_reg
- .byte \type
- .byte \signal
- .balign 4
- .popsection
+ __UNWIND_HINT(.Lhere_\@, \type, \sp_reg, \sp_offset, \signal)
.endm
.macro STACK_FRAME_NON_STANDARD func:req
@@ -113,10 +112,7 @@
.macro ANNOTATE type:req
.Lhere_\@:
- .pushsection .discard.annotate_insn,"M",@progbits,8
- .long .Lhere_\@ - .
- .long \type
- .popsection
+ __ASM_ANNOTATE(.Lhere_\@, \type)
.endm
#endif /* __ASSEMBLY__ */
@@ -125,11 +121,12 @@
#ifndef __ASSEMBLY__
-#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)
+
+#define UNWIND_HINT(type, sp_reg, sp_offset, signal) ""
+#define ASM_ANNOTATE(type) ""
+#define ASM_ANNOTATE_LABEL(sym, type) ""
#else
.macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0
.endm
@@ -146,30 +143,30 @@
* 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))
+#define ANNOTATE_NOENDBR ASM_ANNOTATE(NOENDBR)
+#define ANNOTATE_NOENDBR_SYM(sym) asm(ASM_ANNOTATE_LABEL(sym, 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)
+#define ANNOTATE_RETPOLINE_SAFE ASM_ANNOTATE(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)
+#define ANNOTATE_INSTR_BEGIN(label) ASM_ANNOTATE_LABEL(label, INSTR_BEGIN)
+#define ANNOTATE_INSTR_END(label) ASM_ANNOTATE_LABEL(label, INSTR_END)
/*
* objtool annotation to ignore the alternatives and only consider the original
* instruction(s).
*/
-#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(ANNOTYPE_IGNORE_ALTS)
+#define ANNOTATE_IGNORE_ALTERNATIVE ASM_ANNOTATE(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)
+#define ANNOTATE_INTRA_FUNCTION_CALL ASM_ANNOTATE(INTRA_FUNCTION_CALL)
/*
* Use objtool to validate the entry requirement that all code paths do
* VALIDATE_UNRET_END before RET.
@@ -177,13 +174,13 @@
* 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)
+#define ANNOTATE_UNRET_BEGIN ASM_ANNOTATE(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)
+#define ANNOTATE_REACHABLE(label) ASM_ANNOTATE_LABEL(label, REACHABLE)
#else
#define ANNOTATE_NOENDBR ANNOTATE type=ANNOTYPE_NOENDBR
--
2.49.0On Tue, Apr 08, 2025 at 01:21:18AM -0700, Josh Poimboeuf wrote: > Improve the readability and compactness of the objtool annotations. > This makes it easier to see them and differentiate from other code. > > Before: > ------- > > 911: > .pushsection .discard.annotate_insn,"M",@progbits,8 > .long 911b - . > .long 1 > .popsection > > After: > ------ > > # <ANNOTATE_NOENDBR> > 911: .pushsection .discard.annotate_insn,"M",@progbits,8; .long 911b - .; .long 1; .popsection > # </ANNOTATE_NOENDBR> Conversely, I don't mind the compact form here too much, since the only bit that really matters is the annotation type (1, in the above case) and that is already explicit in the marker (ANNOTATE_NOENDBR).
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