diff options
Diffstat (limited to 'arch/x86/include/asm/nospec-branch.h')
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 44 |
1 files changed, 25 insertions, 19 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index ee642d26e304..bc4fa6d09d29 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -219,9 +219,8 @@ .endm /* - * Equivalent to -mindirect-branch-cs-prefix; emit the 5 byte jmp/call - * to the retpoline thunk with a CS prefix when the register requires - * a RAX prefix byte to encode. Also see apply_retpolines(). + * Emits a conditional CS prefix that is compatible with + * -mindirect-branch-cs-prefix. */ .macro __CS_PREFIX reg:req .irp rs,r8,r9,r10,r11,r12,r13,r14,r15 @@ -365,10 +364,14 @@ ".long 999b\n\t" \ ".popsection\n\t" +#define ITS_THUNK_SIZE 64 + typedef u8 retpoline_thunk_t[RETPOLINE_THUNK_SIZE]; +typedef u8 its_thunk_t[ITS_THUNK_SIZE]; extern retpoline_thunk_t __x86_indirect_thunk_array[]; extern retpoline_thunk_t __x86_indirect_call_thunk_array[]; extern retpoline_thunk_t __x86_indirect_jump_thunk_array[]; +extern its_thunk_t __x86_indirect_its_thunk_array[]; #ifdef CONFIG_RETHUNK extern void __x86_return_thunk(void); @@ -392,6 +395,12 @@ static inline void srso_return_thunk(void) {} static inline void srso_alias_return_thunk(void) {} #endif +#ifdef CONFIG_MITIGATION_ITS +extern void its_return_thunk(void); +#else +static inline void its_return_thunk(void) {} +#endif + extern void retbleed_return_thunk(void); extern void srso_return_thunk(void); extern void srso_alias_return_thunk(void); @@ -412,11 +421,6 @@ extern void (*x86_return_thunk)(void); #ifdef CONFIG_CALL_DEPTH_TRACKING extern void __x86_return_skl(void); -static inline void x86_set_skl_return_thunk(void) -{ - x86_return_thunk = &__x86_return_skl; -} - #define CALL_DEPTH_ACCOUNT \ ALTERNATIVE("", \ __stringify(INCREMENT_CALL_DEPTH), \ @@ -429,7 +433,6 @@ DECLARE_PER_CPU(u64, __x86_stuffs_count); DECLARE_PER_CPU(u64, __x86_ctxsw_count); #endif #else -static inline void x86_set_skl_return_thunk(void) {} #define CALL_DEPTH_ACCOUNT "" @@ -455,19 +458,22 @@ static inline void x86_set_skl_return_thunk(void) {} #ifdef CONFIG_X86_64 /* + * Emits a conditional CS prefix that is compatible with + * -mindirect-branch-cs-prefix. + */ +#define __CS_PREFIX(reg) \ + ".irp rs,r8,r9,r10,r11,r12,r13,r14,r15\n" \ + ".ifc \\rs," reg "\n" \ + ".byte 0x2e\n" \ + ".endif\n" \ + ".endr\n" + +/* * Inline asm uses the %V modifier which is only in newer GCC * which is ensured when CONFIG_RETPOLINE is defined. */ -# define CALL_NOSPEC \ - ALTERNATIVE_2( \ - ANNOTATE_RETPOLINE_SAFE \ - "call *%[thunk_target]\n", \ - "call __x86_indirect_thunk_%V[thunk_target]\n", \ - X86_FEATURE_RETPOLINE, \ - "lfence;\n" \ - ANNOTATE_RETPOLINE_SAFE \ - "call *%[thunk_target]\n", \ - X86_FEATURE_RETPOLINE_LFENCE) +#define CALL_NOSPEC __CS_PREFIX("%V[thunk_target]") \ + "call __x86_indirect_thunk_%V[thunk_target]\n" # define THUNK_TARGET(addr) [thunk_target] "r" (addr) |