diff options
Diffstat (limited to 'arch/x86/include/asm/calling.h')
| -rw-r--r-- | arch/x86/include/asm/calling.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/include/asm/calling.h b/arch/x86/include/asm/calling.h index cb4c73bfeb48..129e29721835 100644 --- a/arch/x86/include/asm/calling.h +++ b/arch/x86/include/asm/calling.h @@ -47,6 +47,7 @@ For 32-bit we have the following conventions - kernel is built with */ #include <asm/dwarf2.h> +#include <asm/cpufeatures.h> #ifdef CONFIG_X86_64 @@ -195,6 +196,23 @@ 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 */ /* |