| Message ID | e0dcc9cbd1437429da9ff01b6bc016ec3794d9af.1442523997.git.luto@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 77d8b284e4a7..9eda52205d42 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -73,7 +73,10 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr, asm volatile("2: rdmsr ; xor %[err],%[err]\n" "1:\n\t" ".section .fixup,\"ax\"\n\t" - "3: mov %[fault],%[err] ; jmp 1b\n\t" + "3: mov %[fault],%[err]\n\t" + "xorl %%eax, %%eax\n\t" + "xorl %%edx, %%edx\n\t" + "jmp 1b\n\t" ".previous\n\t" _ASM_EXTABLE(2b, 3b) : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
This will cause unchecked native_rdmsr_safe failures to return deterministic results. We could poison the results with something other than zero, but that would increase code size. Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/include/asm/msr.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)