diff options
Diffstat (limited to 'arch/x86/include/asm/linkage.h')
| -rw-r--r-- | arch/x86/include/asm/linkage.h | 130 |
1 files changed, 104 insertions, 26 deletions
diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 73ca20049835..9d38ae744a2e 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -8,70 +8,148 @@ #undef notrace #define notrace __attribute__((no_instrument_function)) +#ifdef CONFIG_64BIT +/* + * The generic version tends to create spurious ENDBR instructions under + * certain conditions. + */ +#define _THIS_IP_ ({ unsigned long __here; asm ("lea 0(%%rip), %0" : "=r" (__here)); __here; }) +#endif + #ifdef CONFIG_X86_32 #define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0))) #endif /* CONFIG_X86_32 */ -#ifdef __ASSEMBLY__ - -#if defined(CONFIG_X86_64) || defined(CONFIG_X86_ALIGNMENT_16) -#define __ALIGN .p2align 4, 0x90 +#define __ALIGN .balign CONFIG_FUNCTION_ALIGNMENT, 0x90; #define __ALIGN_STR __stringify(__ALIGN) + +#if defined(CONFIG_CALL_PADDING) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#define FUNCTION_PADDING .skip CONFIG_FUNCTION_ALIGNMENT, 0x90; +#else +#define FUNCTION_PADDING +#endif + +#if (CONFIG_FUNCTION_ALIGNMENT > 8) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +# define __FUNC_ALIGN __ALIGN; FUNCTION_PADDING +#else +# define __FUNC_ALIGN __ALIGN #endif -#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#define ASM_FUNC_ALIGN __stringify(__FUNC_ALIGN) +#define SYM_F_ALIGN __FUNC_ALIGN + +#ifdef __ASSEMBLER__ + +#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) #define RET jmp __x86_return_thunk -#else /* CONFIG_RETPOLINE */ -#ifdef CONFIG_SLS +#else /* CONFIG_MITIGATION_RETPOLINE */ +#ifdef CONFIG_MITIGATION_SLS #define RET ret; int3 #else #define RET ret #endif -#endif /* CONFIG_RETPOLINE */ +#endif /* CONFIG_MITIGATION_RETPOLINE */ -#else /* __ASSEMBLY__ */ +#else /* __ASSEMBLER__ */ -#if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) +#if defined(CONFIG_MITIGATION_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) #define ASM_RET "jmp __x86_return_thunk\n\t" -#else /* CONFIG_RETPOLINE */ -#ifdef CONFIG_SLS +#else /* CONFIG_MITIGATION_RETPOLINE */ +#ifdef CONFIG_MITIGATION_SLS #define ASM_RET "ret; int3\n\t" #else #define ASM_RET "ret\n\t" #endif -#endif /* CONFIG_RETPOLINE */ +#endif /* CONFIG_MITIGATION_RETPOLINE */ + +#endif /* __ASSEMBLER__ */ + +/* + * Depending on -fpatchable-function-entry=N,N usage (CONFIG_CALL_PADDING) the + * CFI symbol layout changes. + * + * Without CALL_THUNKS: + * + * .align FUNCTION_ALIGNMENT + * __cfi_##name: + * .skip FUNCTION_PADDING, 0x90 + * .byte 0xb8 + * .long __kcfi_typeid_##name + * name: + * + * With CALL_THUNKS: + * + * .align FUNCTION_ALIGNMENT + * __cfi_##name: + * .byte 0xb8 + * .long __kcfi_typeid_##name + * .skip FUNCTION_PADDING, 0x90 + * name: + * + * In both cases the whole thing is FUNCTION_ALIGNMENT aligned and sized. + */ + +#ifdef CONFIG_CALL_PADDING +#define CFI_PRE_PADDING +#define CFI_POST_PADDING .skip CONFIG_FUNCTION_PADDING_BYTES, 0x90; +#else +#define CFI_PRE_PADDING .skip CONFIG_FUNCTION_PADDING_BYTES, 0x90; +#define CFI_POST_PADDING +#endif -#endif /* __ASSEMBLY__ */ +#define __CFI_TYPE(name) \ + SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE) \ + CFI_PRE_PADDING \ + .byte 0xb8 ASM_NL \ + .long __kcfi_typeid_##name ASM_NL \ + CFI_POST_PADDING \ + SYM_FUNC_END(__cfi_##name) + +/* UML needs to be able to override memcpy() and friends for KASAN. */ +#ifdef CONFIG_UML +# define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS_WEAK +#else +# define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS +#endif + +/* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */ +#define SYM_TYPED_FUNC_START(name) \ + SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \ + ENDBR /* SYM_FUNC_START -- use for global functions */ #define SYM_FUNC_START(name) \ - SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \ - ENDBR + SYM_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) /* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */ #define SYM_FUNC_START_NOALIGN(name) \ - SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) \ - ENDBR + SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) /* SYM_FUNC_START_LOCAL -- use for local functions */ #define SYM_FUNC_START_LOCAL(name) \ - SYM_START(name, SYM_L_LOCAL, SYM_A_ALIGN) \ - ENDBR + SYM_START(name, SYM_L_LOCAL, SYM_F_ALIGN) /* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */ #define SYM_FUNC_START_LOCAL_NOALIGN(name) \ - SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) \ - ENDBR + SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) /* SYM_FUNC_START_WEAK -- use for weak functions */ #define SYM_FUNC_START_WEAK(name) \ - SYM_START(name, SYM_L_WEAK, SYM_A_ALIGN) \ - ENDBR + SYM_START(name, SYM_L_WEAK, SYM_F_ALIGN) /* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */ #define SYM_FUNC_START_WEAK_NOALIGN(name) \ - SYM_START(name, SYM_L_WEAK, SYM_A_NONE) \ - ENDBR + SYM_START(name, SYM_L_WEAK, SYM_A_NONE) + +/* + * Expose 'sym' to the startup code in arch/x86/boot/startup/, by emitting an + * alias prefixed with __pi_ + */ +#ifdef __ASSEMBLER__ +#define SYM_PIC_ALIAS(sym) SYM_ALIAS(__pi_ ## sym, sym, SYM_L_GLOBAL) +#else +#define SYM_PIC_ALIAS(sym) extern typeof(sym) __PASTE(__pi_, sym) __alias(sym) +#endif #endif /* _ASM_X86_LINKAGE_H */ |