Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/linux/instrumentation.h | 11 +++-----
include/linux/objtool.h | 9 ++++--
include/linux/objtool_types.h | 2 +
tools/include/linux/objtool_types.h | 2 +
tools/objtool/check.c | 49 +++++++-----------------------------
5 files changed, 25 insertions(+), 48 deletions(-)
--- a/include/linux/instrumentation.h
+++ b/include/linux/instrumentation.h
@@ -4,14 +4,14 @@
#ifdef CONFIG_NOINSTR_VALIDATION
+#include <linux/objtool.h>
#include <linux/stringify.h>
/* Begin/end of an instrumentation safe region */
#define __instrumentation_begin(c) ({ \
asm volatile(__stringify(c) ": nop\n\t" \
- ".pushsection .discard.instr_begin\n\t" \
- ".long " __stringify(c) "b - .\n\t" \
- ".popsection\n\t" : : "i" (c)); \
+ __ASM_ANNOTATE(c, ANNOTYPE_INSTR_BEGIN) \
+ : : "i" (c)); \
})
#define instrumentation_begin() __instrumentation_begin(__COUNTER__)
@@ -48,9 +48,8 @@
*/
#define __instrumentation_end(c) ({ \
asm volatile(__stringify(c) ": nop\n\t" \
- ".pushsection .discard.instr_end\n\t" \
- ".long " __stringify(c) "b - .\n\t" \
- ".popsection\n\t" : : "i" (c)); \
+ __ASM_ANNOTATE(c, ANNOTYPE_INSTR_END) \
+ : : "i" (c)); \
})
#define instrumentation_end() __instrumentation_end(__COUNTER__)
#else /* !CONFIG_NOINSTR_VALIDATION */
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -51,13 +51,16 @@
".long 998b\n\t" \
".popsection\n\t"
-#define ASM_ANNOTATE(x) \
- "911:\n\t" \
+#define __ASM_ANNOTATE(s, x) \
".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \
- ".long 911b - .\n\t" \
+ ".long " __stringify(s) "b - .\n\t" \
".long " __stringify(x) "\n\t" \
".popsection\n\t"
+#define ASM_ANNOTATE(x) \
+ "911:\n\t" \
+ __ASM_ANNOTATE(911, x)
+
#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
#else /* __ASSEMBLY__ */
--- a/include/linux/objtool_types.h
+++ b/include/linux/objtool_types.h
@@ -59,5 +59,7 @@ struct unwind_hint {
*/
#define ANNOTYPE_NOENDBR 1
#define ANNOTYPE_RETPOLINE_SAFE 2
+#define ANNOTYPE_INSTR_BEGIN 3
+#define ANNOTYPE_INSTR_END 4
#endif /* _LINUX_OBJTOOL_TYPES_H */
--- a/tools/include/linux/objtool_types.h
+++ b/tools/include/linux/objtool_types.h
@@ -59,5 +59,7 @@ struct unwind_hint {
*/
#define ANNOTYPE_NOENDBR 1
#define ANNOTYPE_RETPOLINE_SAFE 2
+#define ANNOTYPE_INSTR_BEGIN 3
+#define ANNOTYPE_INSTR_END 4
#endif /* _LINUX_OBJTOOL_TYPES_H */
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -2367,48 +2367,19 @@ static int __annotate_retpoline_safe(int
return 0;
}
-static int read_instr_hints(struct objtool_file *file)
+static int __annotate_instr(int type, struct instruction *insn)
{
- struct section *rsec;
- struct instruction *insn;
- struct reloc *reloc;
-
- rsec = find_section_by_name(file->elf, ".rela.discard.instr_end");
- if (!rsec)
- return 0;
-
- for_each_reloc(rsec, reloc) {
- if (reloc->sym->type != STT_SECTION) {
- WARN("unexpected relocation symbol type in %s", rsec->name);
- return -1;
- }
-
- insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
- if (!insn) {
- WARN("bad .discard.instr_end entry");
- return -1;
- }
+ switch (type) {
+ case ANNOTYPE_INSTR_BEGIN:
+ insn->instr++;
+ break;
+ case ANNOTYPE_INSTR_END:
insn->instr--;
- }
-
- rsec = find_section_by_name(file->elf, ".rela.discard.instr_begin");
- if (!rsec)
- return 0;
+ break;
- for_each_reloc(rsec, reloc) {
- if (reloc->sym->type != STT_SECTION) {
- WARN("unexpected relocation symbol type in %s", rsec->name);
- return -1;
- }
-
- insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
- if (!insn) {
- WARN("bad .discard.instr_begin entry");
- return -1;
- }
-
- insn->instr++;
+ default:
+ break;
}
return 0;
@@ -2654,7 +2625,7 @@ static int decode_sections(struct objtoo
if (ret)
return ret;
- ret = read_instr_hints(file);
+ ret = read_annotate(file, __annotate_instr);
if (ret)
return ret;On Mon, Nov 11, 2024 at 12:59:39PM +0100, Peter Zijlstra wrote: > +++ b/include/linux/objtool.h > @@ -51,13 +51,16 @@ > ".long 998b\n\t" \ > ".popsection\n\t" > > -#define ASM_ANNOTATE(x) \ > - "911:\n\t" \ > +#define __ASM_ANNOTATE(s, x) \ > ".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \ > - ".long 911b - .\n\t" \ > + ".long " __stringify(s) "b - .\n\t" \ It would probably be better for __ASM_ANNOTATE's callers to pass in the full label name (e.g. '911b') since they know where the label is? It could even be a named label. -- Josh
On Fri, Nov 15, 2024 at 10:40:08AM -0800, Josh Poimboeuf wrote:
> On Mon, Nov 11, 2024 at 12:59:39PM +0100, Peter Zijlstra wrote:
> > +++ b/include/linux/objtool.h
> > @@ -51,13 +51,16 @@
> > ".long 998b\n\t" \
> > ".popsection\n\t"
> >
> > -#define ASM_ANNOTATE(x) \
> > - "911:\n\t" \
> > +#define __ASM_ANNOTATE(s, x) \
> > ".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \
> > - ".long 911b - .\n\t" \
> > + ".long " __stringify(s) "b - .\n\t" \
>
> It would probably be better for __ASM_ANNOTATE's callers to pass in the
> full label name (e.g. '911b') since they know where the label is? It
> could even be a named label.
This seems to work.
--- a/include/linux/instrumentation.h
+++ b/include/linux/instrumentation.h
@@ -6,11 +6,12 @@
#include <linux/objtool.h>
#include <linux/stringify.h>
+#include <linux/args.h>
/* Begin/end of an instrumentation safe region */
#define __instrumentation_begin(c) ({ \
asm volatile(__stringify(c) ": nop\n\t" \
- __ASM_ANNOTATE(c, ANNOTYPE_INSTR_BEGIN) \
+ __ASM_ANNOTATE(CONCATENATE(c, b), ANNOTYPE_INSTR_BEGIN) \
: : "i" (c)); \
})
#define instrumentation_begin() __instrumentation_begin(__COUNTER__)
@@ -48,7 +49,7 @@
*/
#define __instrumentation_end(c) ({ \
asm volatile(__stringify(c) ": nop\n\t" \
- __ASM_ANNOTATE(c, ANNOTYPE_INSTR_END) \
+ __ASM_ANNOTATE(CONCATENATE(c, b), ANNOTYPE_INSTR_END) \
: : "i" (c)); \
})
#define instrumentation_end() __instrumentation_end(__COUNTER__)
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -53,13 +53,13 @@
#define __ASM_ANNOTATE(s, x) \
".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \
- ".long " __stringify(s) "b - .\n\t" \
+ ".long " __stringify(s) " - .\n\t" \
".long " __stringify(x) "\n\t" \
".popsection\n\t"
#define ASM_ANNOTATE(x) \
"911:\n\t" \
- __ASM_ANNOTATE(911, x)
+ __ASM_ANNOTATE(911b, x)
#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)
On Fri, Nov 15, 2024 at 10:40:08AM -0800, Josh Poimboeuf wrote: > On Mon, Nov 11, 2024 at 12:59:39PM +0100, Peter Zijlstra wrote: > > +++ b/include/linux/objtool.h > > @@ -51,13 +51,16 @@ > > ".long 998b\n\t" \ > > ".popsection\n\t" > > > > -#define ASM_ANNOTATE(x) \ > > - "911:\n\t" \ > > +#define __ASM_ANNOTATE(s, x) \ > > ".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \ > > - ".long 911b - .\n\t" \ > > + ".long " __stringify(s) "b - .\n\t" \ > > It would probably be better for __ASM_ANNOTATE's callers to pass in the > full label name (e.g. '911b') since they know where the label is? It > could even be a named label. I have this somewhere later, changing it here would be a pain because the existing annotations dont do it like that.
On Sat, Nov 16, 2024 at 10:36:26AM +0100, Peter Zijlstra wrote: > On Fri, Nov 15, 2024 at 10:40:08AM -0800, Josh Poimboeuf wrote: > > On Mon, Nov 11, 2024 at 12:59:39PM +0100, Peter Zijlstra wrote: > > > +++ b/include/linux/objtool.h > > > @@ -51,13 +51,16 @@ > > > ".long 998b\n\t" \ > > > ".popsection\n\t" > > > > > > -#define ASM_ANNOTATE(x) \ > > > - "911:\n\t" \ > > > +#define __ASM_ANNOTATE(s, x) \ > > > ".pushsection .discard.annotate,\"M\",@progbits,8\n\t" \ > > > - ".long 911b - .\n\t" \ > > > + ".long " __stringify(s) "b - .\n\t" \ > > > > It would probably be better for __ASM_ANNOTATE's callers to pass in the > > full label name (e.g. '911b') since they know where the label is? It > > could even be a named label. > > I have this somewhere later, changing it here would be a pain because > the existing annotations dont do it like that. Reading is hard, yes let me do what you said.
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