diff options
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 747549934fe3..17a236a8b237 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -35,6 +35,7 @@ * the optimal version — two calls, each with their own speculation * trap should their return address end up getting used, in a loop. */ +#ifdef CONFIG_X86_64 #define __FILL_RETURN_BUFFER(reg, nr, sp) \ mov $(nr/2), reg; \ 771: \ @@ -55,6 +56,19 @@ add $(BITS_PER_LONG/8) * nr, sp; \ /* barrier for jnz misprediction */ \ lfence; +#else +/* + * i386 doesn't unconditionally have LFENCE, as such it can't + * do a loop. + */ +#define __FILL_RETURN_BUFFER(reg, nr, sp) \ + .rept nr; \ + call 772f; \ + int3; \ +772:; \ + .endr; \ + add $(BITS_PER_LONG/8) * nr, sp; +#endif /* Sequence to mitigate PBRSB on eIBRS CPUs */ #define __ISSUE_UNBALANCED_RET_GUARD(sp) \ |