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, end) \ 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 ".byte " __stringify(end) "\n\t" \ 23 ".balign 4 \n\t" \ 24 ".popsection\n\t" 25 26 /* 27 * This macro marks the given function's stack frame as "non-standard", which 28 * tells objtool to ignore the function when doing stack metadata validation. 29 * It should only be used in special cases where you're 100% sure it won't 30 * affect the reliability of frame pointers and kernel stack traces. 31 * 32 * For more information, see tools/objtool/Documentation/objtool.txt. 33 */ 34 #define STACK_FRAME_NON_STANDARD(func) \ 35 static void __used __section(".discard.func_stack_frame_non_standard") \ 36 *__func_stack_frame_non_standard_##func = func 37 38 /* 39 * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore 40 * for the case where a function is intentionally missing frame pointer setup, 41 * but otherwise needs objtool/ORC coverage when frame pointers are disabled. 42 */ 43 #ifdef CONFIG_FRAME_POINTER 44 #define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func) 45 #else 46 #define STACK_FRAME_NON_STANDARD_FP(func) 47 #endif 48 49 #define ANNOTATE_NOENDBR \ 50 "986: \n\t" \ 51 ".pushsection .discard.noendbr\n\t" \ 52 ".long 986b - .\n\t" \ 53 ".popsection\n\t" 54 55 #define ASM_REACHABLE \ 56 "998:\n\t" \ 57 ".pushsection .discard.reachable\n\t" \ 58 ".long 998b - .\n\t" \ 59 ".popsection\n\t" 60 61 #else /* __ASSEMBLY__ */ 62 63 /* 64 * This macro indicates that the following intra-function call is valid. 65 * Any non-annotated intra-function call will cause objtool to issue a warning. 66 */ 67 #define ANNOTATE_INTRA_FUNCTION_CALL \ 68 999: \ 69 .pushsection .discard.intra_function_calls; \ 70 .long 999b - .; \ 71 .popsection; 72 73 /* 74 * In asm, there are two kinds of code: normal C-type callable functions and 75 * the rest. The normal callable functions can be called by other code, and 76 * don't do anything unusual with the stack. Such normal callable functions 77 * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this 78 * category. In this case, no special debugging annotations are needed because 79 * objtool can automatically generate the ORC data for the ORC unwinder to read 80 * at runtime. 81 * 82 * Anything which doesn't fall into the above category, such as syscall and 83 * interrupt handlers, tends to not be called directly by other functions, and 84 * often does unusual non-C-function-type things with the stack pointer. Such 85 * code needs to be annotated such that objtool can understand it. The 86 * following CFI hint macros are for this type of code. 87 * 88 * These macros provide hints to objtool about the state of the stack at each 89 * instruction. Objtool starts from the hints and follows the code flow, 90 * making automatic CFI adjustments when it sees pushes and pops, filling out 91 * the debuginfo as necessary. It will also warn if it sees any 92 * inconsistencies. 93 */ 94 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0 95 .Lhere_\@: 96 .pushsection .discard.unwind_hints 97 /* struct unwind_hint */ 98 .long .Lhere_\@ - . 99 .short \sp_offset 100 .byte \sp_reg 101 .byte \type 102 .byte \signal 103 .byte \end 104 .balign 4 105 .popsection 106 .endm 107 108 .macro STACK_FRAME_NON_STANDARD func:req 109 .pushsection .discard.func_stack_frame_non_standard, "aw" 110 .long \func - . 111 .popsection 112 .endm 113 114 .macro STACK_FRAME_NON_STANDARD_FP func:req 115 #ifdef CONFIG_FRAME_POINTER 116 STACK_FRAME_NON_STANDARD \func 117 #endif 118 .endm 119 120 .macro ANNOTATE_NOENDBR 121 .Lhere_\@: 122 .pushsection .discard.noendbr 123 .long .Lhere_\@ - . 124 .popsection 125 .endm 126 127 .macro REACHABLE 128 .Lhere_\@: 129 .pushsection .discard.reachable 130 .long .Lhere_\@ - . 131 .popsection 132 .endm 133 134 #endif /* __ASSEMBLY__ */ 135 136 #else /* !CONFIG_OBJTOOL */ 137 138 #ifndef __ASSEMBLY__ 139 140 #define UNWIND_HINT(type, sp_reg, sp_offset, signal, end) "\n\t" 141 #define STACK_FRAME_NON_STANDARD(func) 142 #define STACK_FRAME_NON_STANDARD_FP(func) 143 #define ANNOTATE_NOENDBR 144 #define ASM_REACHABLE 145 #else 146 #define ANNOTATE_INTRA_FUNCTION_CALL 147 .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0 148 .endm 149 .macro STACK_FRAME_NON_STANDARD func:req 150 .endm 151 .macro ANNOTATE_NOENDBR 152 .endm 153 .macro REACHABLE 154 .endm 155 #endif 156 157 #endif /* CONFIG_OBJTOOL */ 158 159 #endif /* _LINUX_OBJTOOL_H */ 160