From: Andi Kleen <[email protected]> With the latest tip x86/pti I get oopses when booting a 64bit VM in qemu with RETPOLINE/gcc7 and PTI enabled.
The following patch fixes it for me. Something doesn't seem to work with ALTERNATIVE_2. It adds only a few bytes more code, so seems acceptable. Signed-off-by: Andi Kleen <[email protected]> --- arch/x86/include/asm/nospec-branch.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 8ddf8513550e..eea6340a0abb 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -46,9 +46,8 @@ */ .macro JMP_NOSPEC reg:req #ifdef CONFIG_RETPOLINE - ALTERNATIVE_2 __stringify(jmp *\reg), \ - __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \ - __stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD + ALTERNATIVE "", __stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD + ALTERNATIVE __stringify(jmp *\reg), __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE #else jmp *\reg #endif -- 2.14.3
