diff options
Diffstat (limited to 'arch/x86/include/asm/nospec-branch.h')
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 80 |
1 files changed, 22 insertions, 58 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 7e9a281e2660..e7752b4038ff 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -4,20 +4,13 @@ #define _ASM_X86_NOSPEC_BRANCH_H_ #include <linux/static_key.h> +#include <linux/frame.h> #include <asm/alternative.h> #include <asm/alternative-asm.h> #include <asm/cpufeatures.h> #include <asm/msr-index.h> - -/* - * This should be used immediately before a retpoline alternative. It tells - * objtool where the retpolines are so that it can make sense of the control - * flow by just reading the original instruction(s) and ignoring the - * alternatives. - */ -#define ANNOTATE_NOSPEC_ALTERNATIVE \ - ANNOTATE_IGNORE_ALTERNATIVE +#include <asm/unwind_hints.h> /* * Fill the CPU return stack buffer. @@ -46,21 +39,25 @@ #define __FILL_RETURN_BUFFER(reg, nr, sp) \ mov $(nr/2), reg; \ 771: \ + ANNOTATE_INTRA_FUNCTION_CALL; \ call 772f; \ 773: /* speculation trap */ \ + UNWIND_HINT_EMPTY; \ pause; \ lfence; \ jmp 773b; \ 772: \ + ANNOTATE_INTRA_FUNCTION_CALL; \ call 774f; \ 775: /* speculation trap */ \ + UNWIND_HINT_EMPTY; \ pause; \ lfence; \ jmp 775b; \ 774: \ + add $(BITS_PER_LONG/8) * 2, sp; \ dec reg; \ - jnz 771b; \ - add $(BITS_PER_LONG/8) * nr, sp; + jnz 771b; #ifdef __ASSEMBLY__ @@ -77,57 +74,27 @@ .endm /* - * These are the bare retpoline primitives for indirect jmp and call. - * Do not use these directly; they only exist to make the ALTERNATIVE - * invocation below less ugly. - */ -.macro RETPOLINE_JMP reg:req - call .Ldo_rop_\@ -.Lspec_trap_\@: - pause - lfence - jmp .Lspec_trap_\@ -.Ldo_rop_\@: - mov \reg, (%_ASM_SP) - ret -.endm - -/* - * This is a wrapper around RETPOLINE_JMP so the called function in reg - * returns to the instruction after the macro. - */ -.macro RETPOLINE_CALL reg:req - jmp .Ldo_call_\@ -.Ldo_retpoline_jmp_\@: - RETPOLINE_JMP \reg -.Ldo_call_\@: - call .Ldo_retpoline_jmp_\@ -.endm - -/* * JMP_NOSPEC and CALL_NOSPEC macros can be used instead of a simple * indirect jmp/call which may be susceptible to the Spectre variant 2 * attack. */ .macro JMP_NOSPEC reg:req #ifdef CONFIG_RETPOLINE - ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg), \ - __stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \ - __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RETPOLINE_AMD + ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *%\reg), \ + __stringify(jmp __x86_retpoline_\reg), X86_FEATURE_RETPOLINE, \ + __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *%\reg), X86_FEATURE_RETPOLINE_AMD #else - jmp *\reg + jmp *%\reg #endif .endm .macro CALL_NOSPEC reg:req #ifdef CONFIG_RETPOLINE - ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg), \ - __stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\ - __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RETPOLINE_AMD + ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *%\reg), \ + __stringify(call __x86_retpoline_\reg), X86_FEATURE_RETPOLINE, \ + __stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *%\reg), X86_FEATURE_RETPOLINE_AMD #else - call *\reg + call *%\reg #endif .endm @@ -137,10 +104,8 @@ */ .macro FILL_RETURN_BUFFER reg:req nr:req ftr:req #ifdef CONFIG_RETPOLINE - ANNOTATE_NOSPEC_ALTERNATIVE - ALTERNATIVE "jmp .Lskip_rsb_\@", \ - __stringify(__FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP)) \ - \ftr + ALTERNATIVE "jmp .Lskip_rsb_\@", "", \ftr + __FILL_RETURN_BUFFER(\reg,\nr,%_ASM_SP) .Lskip_rsb_\@: #endif .endm @@ -161,16 +126,16 @@ * which is ensured when CONFIG_RETPOLINE is defined. */ # define CALL_NOSPEC \ - ANNOTATE_NOSPEC_ALTERNATIVE \ ALTERNATIVE_2( \ ANNOTATE_RETPOLINE_SAFE \ "call *%[thunk_target]\n", \ - "call __x86_indirect_thunk_%V[thunk_target]\n", \ + "call __x86_retpoline_%V[thunk_target]\n", \ X86_FEATURE_RETPOLINE, \ "lfence;\n" \ ANNOTATE_RETPOLINE_SAFE \ "call *%[thunk_target]\n", \ X86_FEATURE_RETPOLINE_AMD) + # define THUNK_TARGET(addr) [thunk_target] "r" (addr) #else /* CONFIG_X86_32 */ @@ -180,7 +145,6 @@ * here, anyway. */ # define CALL_NOSPEC \ - ANNOTATE_NOSPEC_ALTERNATIVE \ ALTERNATIVE_2( \ ANNOTATE_RETPOLINE_SAFE \ "call *%[thunk_target]\n", \ @@ -298,7 +262,7 @@ DECLARE_STATIC_KEY_FALSE(mds_idle_clear); * combination with microcode which triggers a CPU buffer flush when the * instruction is executed. */ -static inline void mds_clear_cpu_buffers(void) +static __always_inline void mds_clear_cpu_buffers(void) { static const u16 ds = __KERNEL_DS; @@ -319,7 +283,7 @@ static inline void mds_clear_cpu_buffers(void) * * Clear CPU buffers if the corresponding static key is enabled */ -static inline void mds_user_clear_cpu_buffers(void) +static __always_inline void mds_user_clear_cpu_buffers(void) { if (static_branch_likely(&mds_user_clear)) mds_clear_cpu_buffers(); |