1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_LINKAGE_H 3 #define _ASM_X86_LINKAGE_H 4 5 #include <linux/stringify.h> 6 #include <asm/ibt.h> 7 8 #undef notrace 9 #define notrace __attribute__((no_instrument_function)) 10 11 #ifdef CONFIG_64BIT 12 /* 13 * The generic version tends to create spurious ENDBR instructions under 14 * certain conditions. 15 */ 16 #define _THIS_IP_ ({ unsigned long __here; asm ("lea 0(%%rip), %0" : "=r" (__here)); __here; }) 17 #endif 18 19 #ifdef CONFIG_X86_32 20 #define asmlinkage CPP_ASMLINKAGE __attribute__((regparm(0))) 21 #endif /* CONFIG_X86_32 */ 22 23 #define __ALIGN .balign CONFIG_FUNCTION_ALIGNMENT, 0x90; 24 #define __ALIGN_STR __stringify(__ALIGN) 25 26 #if defined(CONFIG_CALL_PADDING) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) 27 #define FUNCTION_PADDING .skip CONFIG_FUNCTION_ALIGNMENT, 0x90; 28 #else 29 #define FUNCTION_PADDING 30 #endif 31 32 #if (CONFIG_FUNCTION_ALIGNMENT > 8) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) 33 # define __FUNC_ALIGN __ALIGN; FUNCTION_PADDING 34 #else 35 # define __FUNC_ALIGN __ALIGN 36 #endif 37 38 #define ASM_FUNC_ALIGN __stringify(__FUNC_ALIGN) 39 #define SYM_F_ALIGN __FUNC_ALIGN 40 41 #ifdef __ASSEMBLY__ 42 43 #if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) 44 #define RET jmp __x86_return_thunk 45 #else /* CONFIG_RETPOLINE */ 46 #ifdef CONFIG_SLS 47 #define RET ret; int3 48 #else 49 #define RET ret 50 #endif 51 #endif /* CONFIG_RETPOLINE */ 52 53 #else /* __ASSEMBLY__ */ 54 55 #if defined(CONFIG_RETHUNK) && !defined(__DISABLE_EXPORTS) && !defined(BUILD_VDSO) 56 #define ASM_RET "jmp __x86_return_thunk\n\t" 57 #else /* CONFIG_RETPOLINE */ 58 #ifdef CONFIG_SLS 59 #define ASM_RET "ret; int3\n\t" 60 #else 61 #define ASM_RET "ret\n\t" 62 #endif 63 #endif /* CONFIG_RETPOLINE */ 64 65 #endif /* __ASSEMBLY__ */ 66 67 /* 68 * Depending on -fpatchable-function-entry=N,N usage (CONFIG_CALL_PADDING) the 69 * CFI symbol layout changes. 70 * 71 * Without CALL_THUNKS: 72 * 73 * .align FUNCTION_ALIGNMENT 74 * __cfi_##name: 75 * .skip FUNCTION_PADDING, 0x90 76 * .byte 0xb8 77 * .long __kcfi_typeid_##name 78 * name: 79 * 80 * With CALL_THUNKS: 81 * 82 * .align FUNCTION_ALIGNMENT 83 * __cfi_##name: 84 * .byte 0xb8 85 * .long __kcfi_typeid_##name 86 * .skip FUNCTION_PADDING, 0x90 87 * name: 88 * 89 * In both cases the whole thing is FUNCTION_ALIGNMENT aligned and sized. 90 */ 91 92 #ifdef CONFIG_CALL_PADDING 93 #define CFI_PRE_PADDING 94 #define CFI_POST_PADDING .skip CONFIG_FUNCTION_PADDING_BYTES, 0x90; 95 #else 96 #define CFI_PRE_PADDING .skip CONFIG_FUNCTION_PADDING_BYTES, 0x90; 97 #define CFI_POST_PADDING 98 #endif 99 100 #define __CFI_TYPE(name) \ 101 SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE) \ 102 CFI_PRE_PADDING \ 103 .byte 0xb8 ASM_NL \ 104 .long __kcfi_typeid_##name ASM_NL \ 105 CFI_POST_PADDING \ 106 SYM_FUNC_END(__cfi_##name) 107 108 /* UML needs to be able to override memcpy() and friends for KASAN. */ 109 #ifdef CONFIG_UML 110 # define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS_WEAK 111 #else 112 # define SYM_FUNC_ALIAS_MEMFUNC SYM_FUNC_ALIAS 113 #endif 114 115 /* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */ 116 #define SYM_TYPED_FUNC_START(name) \ 117 SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \ 118 ENDBR 119 120 /* SYM_FUNC_START -- use for global functions */ 121 #define SYM_FUNC_START(name) \ 122 SYM_START(name, SYM_L_GLOBAL, SYM_F_ALIGN) \ 123 ENDBR 124 125 /* SYM_FUNC_START_NOALIGN -- use for global functions, w/o alignment */ 126 #define SYM_FUNC_START_NOALIGN(name) \ 127 SYM_START(name, SYM_L_GLOBAL, SYM_A_NONE) \ 128 ENDBR 129 130 /* SYM_FUNC_START_LOCAL -- use for local functions */ 131 #define SYM_FUNC_START_LOCAL(name) \ 132 SYM_START(name, SYM_L_LOCAL, SYM_F_ALIGN) \ 133 ENDBR 134 135 /* SYM_FUNC_START_LOCAL_NOALIGN -- use for local functions, w/o alignment */ 136 #define SYM_FUNC_START_LOCAL_NOALIGN(name) \ 137 SYM_START(name, SYM_L_LOCAL, SYM_A_NONE) \ 138 ENDBR 139 140 /* SYM_FUNC_START_WEAK -- use for weak functions */ 141 #define SYM_FUNC_START_WEAK(name) \ 142 SYM_START(name, SYM_L_WEAK, SYM_F_ALIGN) \ 143 ENDBR 144 145 /* SYM_FUNC_START_WEAK_NOALIGN -- use for weak functions, w/o alignment */ 146 #define SYM_FUNC_START_WEAK_NOALIGN(name) \ 147 SYM_START(name, SYM_L_WEAK, SYM_A_NONE) \ 148 ENDBR 149 150 #endif /* _ASM_X86_LINKAGE_H */ 151 152