diff options
Diffstat (limited to 'arch/x86/entry/calling.h')
| -rw-r--r-- | arch/x86/entry/calling.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 3c71dd947c7b..5e24cd248728 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -1,3 +1,5 @@ +#include <asm/cpufeatures.h> + /* x86 function call convention, 64-bit: @@ -199,6 +201,23 @@ For 32-bit we have the following conventions - kernel is built with .byte 0xf1 .endm +/* + * Mitigate Spectre v1 for conditional swapgs code paths. + * + * FENCE_SWAPGS_USER_ENTRY is used in the user entry swapgs code path, to + * prevent a speculative swapgs when coming from kernel space. + * + * FENCE_SWAPGS_KERNEL_ENTRY is used in the kernel entry non-swapgs code path, + * to prevent the swapgs from getting speculatively skipped when coming from + * user space. + */ +.macro FENCE_SWAPGS_USER_ENTRY + ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_USER +.endm +.macro FENCE_SWAPGS_KERNEL_ENTRY + ALTERNATIVE "", "lfence", X86_FEATURE_FENCE_SWAPGS_KERNEL +.endm + #else /* CONFIG_X86_64 */ /* |