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| author | Peter Zijlstra <peterz@infradead.org> | 2022-03-08 16:30:56 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-03-15 10:32:47 +0100 |
| commit | ed53a0d971926e484d86cce617ec02a7ee85c3fe (patch) | |
| tree | 1423484f3912113c56c0b77fa5b0397113040828 /arch/x86/include/asm/alternative.h | |
| parent | objtool: Find unused ENDBR instructions (diff) | |
| download | linux-ed53a0d971926e484d86cce617ec02a7ee85c3fe.tar.xz linux-ed53a0d971926e484d86cce617ec02a7ee85c3fe.zip | |
x86/alternative: Use .ibt_endbr_seal to seal indirect calls
Objtool's --ibt option generates .ibt_endbr_seal which lists
superfluous ENDBR instructions. That is those instructions for which
the function is never indirectly called.
Overwrite these ENDBR instructions with a NOP4 such that these
function can never be indirect called, reducing the number of viable
ENDBR targets in the kernel.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.822545231@infradead.org
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
| -rw-r--r-- | arch/x86/include/asm/alternative.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 58eee6402832..9b10c8c76087 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -76,6 +76,7 @@ extern int alternatives_patched; extern void alternative_instructions(void); extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); extern void apply_retpolines(s32 *start, s32 *end); +extern void apply_ibt_endbr(s32 *start, s32 *end); struct module; |