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objtool: Convert instrumentation_{begin,end}() to ANNOTATE
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Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/20241128094311.245980207@infradead.org
Peter Zijlstra committed Dec 2, 2024
1 parent bf5febe commit 317f2a6
Showing 5 changed files with 28 additions and 48 deletions.
11 changes: 5 additions & 6 deletions include/linux/instrumentation.h
Original file line number Diff line number Diff line change
@@ -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(__ASM_BREF(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(__ASM_BREF(c), ANNOTYPE_INSTR_END) \
: : "i" (c)); \
})
#define instrumentation_end() __instrumentation_end(__COUNTER__)
#else /* !CONFIG_NOINSTR_VALIDATION */
12 changes: 9 additions & 3 deletions include/linux/objtool.h
Original file line number Diff line number Diff line change
@@ -51,13 +51,18 @@
".long 998b\n\t" \
".popsection\n\t"

#define ASM_ANNOTATE(type) \
"911:\n\t" \
#define __ASM_BREF(label) label ## b

#define __ASM_ANNOTATE(label, type) \
".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \
".long 911b - .\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)

#define ANNOTATE_NOENDBR ASM_ANNOTATE(ANNOTYPE_NOENDBR)

#else /* __ASSEMBLY__ */
@@ -161,6 +166,7 @@
#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 ANNOTATE_NOENDBR
#define ASM_REACHABLE
2 changes: 2 additions & 0 deletions include/linux/objtool_types.h
Original file line number Diff line number Diff line change
@@ -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 */
2 changes: 2 additions & 0 deletions tools/include/linux/objtool_types.h
Original file line number Diff line number Diff line change
@@ -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 */
49 changes: 10 additions & 39 deletions tools/objtool/check.c
Original file line number Diff line number Diff line change
@@ -2440,48 +2440,19 @@ static int __annotate_retpoline_safe(int type, struct instruction *insn)
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;

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;
}
break;

insn->instr++;
default:
break;
}

return 0;
@@ -2730,7 +2701,7 @@ static int decode_sections(struct objtool_file *file)
if (ret)
return ret;

ret = read_instr_hints(file);
ret = read_annotate(file, __annotate_instr);
if (ret)
return ret;

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