1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_OBJTOOL_H 3 #define _LINUX_OBJTOOL_H 4 5 #include <linux/objtool_types.h> 6 7 #ifdef CONFIG_OBJTOOL 8 9 #include <asm/asm.h> 10 11 #ifndef __ASSEMBLY__ 12 13 #define UNWIND_HINT(type, sp_reg, sp_offset, signal) \ 14 "987: \n\t" \ 15 ".pushsection .discard.unwind_hints\n\t" \ 16 /* struct unwind_hint */ \ 17 ".long 987b - .\n\t" \ 18 ".short " __stringify(sp_offset) "\n\t" \ 19 ".byte " __stringify(sp_reg) "\n\t" \ 20 ".byte " __stringify(type) "\n\t" \ 21 ".byte " __stringify(signal) "\n\t" \ 22 ".balign 4 \n\t" \ 23 ".popsection\n\t" 24 25 /* 26 * This macro marks the given function's stack frame as "non-standard", which 27 * tells objtool to ignore the function when doing stack metadata validation. 28 * It should only be used in special cases where you're 100% sure it won't 29 * affect the reliability of frame pointers and kernel stack traces. 30 * 31 * For more information, see tools/objtool/Documentation/objtool.txt. 32 */ 33 #define STACK_FRAME_NON_STANDARD(func) \ 34 static void __used __section(".discard.func_stack_frame_non_standard") \ 35 *__func_stack_frame_non_standard_##func = func 36 37 /* 38 * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore 39 * for the case where a function is intentionally missing frame pointer setup, 40 * but otherwise needs objtool/ORC coverage when frame pointers are disabled. 41 */ 42 #ifdef CONFIG_FRAME_POINTER 43 #define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func) 44 #else 45 #define STACK_FRAME_NON_STANDARD_FP(func) 46 #endif 47 48 #define ANNOTATE_NOENDBR \ 49 "986: \n\t" \ 50 ".pushsection .discard.noendbr\n\t" \ 51 ".long 986b\n\t" \ 52 ".popsection\n\t" 53 54 #define ASM_REACHABLE \ 55 "998:\n\t" \ 56 ".pushsection .discard.reachable\n\t" \ 57 ".long 998b\n\t" \ 58 ".popsection\n\t" 59 60 #define ASM_ANNOTATE(type) \ 61 "911:\n\t" \ 62 ".pushsection .discard.annotate_insn,\"M\",@progbits,8\n\t" \ 63 ".long 911b - .\n\t" \ 64 ".long " __stringify(type) "\n\t" \ 65 ".popsection\n\t" 66 67 #else /* __ASSEMBLY__ */ 68 69 /* 70 * This macro indicates that the following intra-function call is valid. 71 * Any non-annotated intra-function call will cause objtool to issue a warning. 72 */ 73 #define ANNOTATE_INTRA_FUNCTION_CALL \ 74 999: \ 75 .pushsection .discard.intra_function_calls; \ 76 .long 999b; \ 77 .popsection; 78 79 /* 80 * In asm, there are two kinds of code: normal C-type callable functions and 81 * the rest. The normal callable functions can be called by other code, and 82 * don't do anything unusual with the stack. Such normal callable functions 83 * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this 84 * category. In this case, no special debugging annotations are needed because 85 * objtool can automatically generate the ORC data for the ORC unwinder to read 86 * at runtime. 87 * 88 * Anything which doesn't fall into the above category, such as syscall and 89 * interrupt handlers, tends to not be called directly by other functions, and 90 * often does unusual non-C-function-type things with the stack pointer. Such 91 * code needs to be annotated such that objtool can understand it. The 92 * following CFI hint macros are for this type of code. 93 * 94 * These macros provide hints to objtool about the state of the stack at each 95 * instruction. Objtool starts from the hints and follows the code flow, 96 * making automatic CFI adjustments when it sees pushes and pops, filling out 97 * the debuginfo as necessary. It will also warn if it sees any 98 * inconsistencies. 99 */ 100 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 101 .Lhere_\@: 102 .pushsection .discard.unwind_hints 103 /* struct unwind_hint */ 104 .long .Lhere_\@ - . 105 .short \sp_offset 106 .byte \sp_reg 107 .byte \type 108 .byte \signal 109 .balign 4 110 .popsection 111 .endm 112 113 .macro STACK_FRAME_NON_STANDARD func:req 114 .pushsection .discard.func_stack_frame_non_standard, "aw" 115 .long \func - . 116 .popsection 117 .endm 118 119 .macro STACK_FRAME_NON_STANDARD_FP func:req 120 #ifdef CONFIG_FRAME_POINTER 121 STACK_FRAME_NON_STANDARD \func 122 #endif 123 .endm 124 125 .macro ANNOTATE_NOENDBR 126 .Lhere_\@: 127 .pushsection .discard.noendbr 128 .long .Lhere_\@ 129 .popsection 130 .endm 131 132 /* 133 * Use objtool to validate the entry requirement that all code paths do 134 * VALIDATE_UNRET_END before RET. 135 * 136 * NOTE: The macro must be used at the beginning of a global symbol, otherwise 137 * it will be ignored. 138 */ 139 .macro VALIDATE_UNRET_BEGIN 140 #if defined(CONFIG_NOINSTR_VALIDATION) && \ 141 (defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO)) 142 .Lhere_\@: 143 .pushsection .discard.validate_unret 144 .long .Lhere_\@ - . 145 .popsection 146 #endif 147 .endm 148 149 .macro REACHABLE 150 .Lhere_\@: 151 .pushsection .discard.reachable 152 .long .Lhere_\@ 153 .popsection 154 .endm 155 156 .macro ANNOTATE type:req 157 .Lhere_\@: 158 .pushsection .discard.annotate_insn,"M",@progbits,8 159 .long .Lhere_\@ - . 160 .long \type 161 .popsection 162 .endm 163 164 #endif /* __ASSEMBLY__ */ 165 166 #else /* !CONFIG_OBJTOOL */ 167 168 #ifndef __ASSEMBLY__ 169 170 #define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t" 171 #define STACK_FRAME_NON_STANDARD(func) 172 #define STACK_FRAME_NON_STANDARD_FP(func) 173 #define ASM_ANNOTATE(type) 174 #define ANNOTATE_NOENDBR 175 #define ASM_REACHABLE 176 #else 177 #define ANNOTATE_INTRA_FUNCTION_CALL 178 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 179 .endm 180 .macro STACK_FRAME_NON_STANDARD func:req 181 .endm 182 .macro ANNOTATE_NOENDBR 183 .endm 184 .macro REACHABLE 185 .endm 186 .macro ANNOTATE type:req 187 .endm 188 #endif 189 190 #endif /* CONFIG_OBJTOOL */ 191 192 #endif /* _LINUX_OBJTOOL_H */ 193