| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | #ifndef _LINUX_OBJTOOL_H |
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| 3 | #define _LINUX_OBJTOOL_H |
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| 4 | |
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| 5 | #include <linux/objtool_types.h> |
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| 6 | #include <linux/annotate.h> |
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| 7 | |
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| 8 | #ifdef CONFIG_OBJTOOL |
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| 9 | |
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| 10 | #ifndef __ASSEMBLY__ |
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| 11 | |
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| 12 | #define UNWIND_HINT(type, sp_reg, sp_offset, signal) \ |
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| 13 | "987: \n\t" \ |
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| 14 | ".pushsection .discard.unwind_hints\n\t" \ |
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| 15 | ANNOTATE_DATA_SPECIAL "\n\t" \ |
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| 16 | /* struct unwind_hint */ \ |
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| 17 | ".long 987b - .\n\t" \ |
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| 18 | ".short " __stringify(sp_offset) "\n\t" \ |
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| 19 | ".byte " __stringify(sp_reg) "\n\t" \ |
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| 20 | ".byte " __stringify(type) "\n\t" \ |
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| 21 | ".byte " __stringify(signal) "\n\t" \ |
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| 22 | ".balign 4 \n\t" \ |
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| 23 | ".popsection\n\t" |
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| 24 | |
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| 25 | /* |
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| 26 | * This macro marks the given function's stack frame as "non-standard", which |
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| 27 | * tells objtool to ignore the function when doing stack metadata validation. |
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| 28 | * It should only be used in special cases where you're 100% sure it won't |
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| 29 | * affect the reliability of frame pointers and kernel stack traces. |
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| 30 | * |
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| 31 | * For more information, see tools/objtool/Documentation/objtool.txt. |
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| 32 | */ |
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| 33 | #define STACK_FRAME_NON_STANDARD(func) \ |
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| 34 | static void __used __section(".discard.func_stack_frame_non_standard") \ |
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| 35 | *__func_stack_frame_non_standard_##func = func |
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| 36 | |
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| 37 | /* |
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| 38 | * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore |
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| 39 | * for the case where a function is intentionally missing frame pointer setup, |
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| 40 | * but otherwise needs objtool/ORC coverage when frame pointers are disabled. |
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| 41 | */ |
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| 42 | #ifdef CONFIG_FRAME_POINTER |
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| 43 | #define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func) |
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| 44 | #else |
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| 45 | #define STACK_FRAME_NON_STANDARD_FP(func) |
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| 46 | #endif |
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| 47 | |
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| 48 | #define ASM_REACHABLE \ |
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| 49 | "998:\n\t" \ |
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| 50 | ".pushsection .discard.reachable\n\t" \ |
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| 51 | ".long 998b\n\t" \ |
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| 52 | ".popsection\n\t" |
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| 53 | |
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| 54 | #define __ASM_BREF(label) label ## b |
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| 55 | |
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| 56 | #else /* __ASSEMBLY__ */ |
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| 57 | |
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| 58 | /* |
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| 59 | * In asm, there are two kinds of code: normal C-type callable functions and |
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| 60 | * the rest. The normal callable functions can be called by other code, and |
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| 61 | * don't do anything unusual with the stack. Such normal callable functions |
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| 62 | * are annotated with SYM_FUNC_{START,END}. Most asm code falls in this |
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| 63 | * category. In this case, no special debugging annotations are needed because |
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| 64 | * objtool can automatically generate the ORC data for the ORC unwinder to read |
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| 65 | * at runtime. |
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| 66 | * |
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| 67 | * Anything which doesn't fall into the above category, such as syscall and |
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| 68 | * interrupt handlers, tends to not be called directly by other functions, and |
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| 69 | * often does unusual non-C-function-type things with the stack pointer. Such |
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| 70 | * code needs to be annotated such that objtool can understand it. The |
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| 71 | * following CFI hint macros are for this type of code. |
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| 72 | * |
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| 73 | * These macros provide hints to objtool about the state of the stack at each |
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| 74 | * instruction. Objtool starts from the hints and follows the code flow, |
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| 75 | * making automatic CFI adjustments when it sees pushes and pops, filling out |
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| 76 | * the debuginfo as necessary. It will also warn if it sees any |
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| 77 | * inconsistencies. |
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| 78 | */ |
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| 79 | .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 |
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| 80 | .Lhere_\@: |
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| 81 | .pushsection .discard.unwind_hints |
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| 82 | ANNOTATE_DATA_SPECIAL |
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| 83 | /* struct unwind_hint */ |
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| 84 | .long .Lhere_\@ - . |
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| 85 | .short \sp_offset |
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| 86 | .byte \sp_reg |
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| 87 | .byte \type |
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| 88 | .byte \signal |
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| 89 | .balign 4 |
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| 90 | .popsection |
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| 91 | .endm |
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| 92 | |
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| 93 | .macro STACK_FRAME_NON_STANDARD func:req |
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| 94 | .pushsection .discard.func_stack_frame_non_standard, "aw" |
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| 95 | .quad \func |
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| 96 | .popsection |
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| 97 | .endm |
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| 98 | |
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| 99 | .macro STACK_FRAME_NON_STANDARD_FP func:req |
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| 100 | #ifdef CONFIG_FRAME_POINTER |
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| 101 | STACK_FRAME_NON_STANDARD \func |
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| 102 | #endif |
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| 103 | .endm |
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| 104 | |
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| 105 | #endif /* __ASSEMBLY__ */ |
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| 106 | |
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| 107 | #else /* !CONFIG_OBJTOOL */ |
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| 108 | |
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| 109 | #ifndef __ASSEMBLY__ |
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| 110 | |
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| 111 | #define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t" |
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| 112 | #define STACK_FRAME_NON_STANDARD(func) |
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| 113 | #define STACK_FRAME_NON_STANDARD_FP(func) |
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| 114 | #else |
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| 115 | .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 |
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| 116 | .endm |
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| 117 | .macro STACK_FRAME_NON_STANDARD func:req |
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| 118 | .endm |
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| 119 | #endif |
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| 120 | |
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| 121 | #endif /* CONFIG_OBJTOOL */ |
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| 122 | |
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| 123 | #if defined(CONFIG_NOINSTR_VALIDATION) && \ |
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| 124 | (defined(CONFIG_MITIGATION_UNRET_ENTRY) || defined(CONFIG_MITIGATION_SRSO)) |
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| 125 | #define VALIDATE_UNRET_BEGIN ANNOTATE_UNRET_BEGIN |
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| 126 | #else |
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| 127 | #define VALIDATE_UNRET_BEGIN |
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| 128 | #endif |
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| 129 | |
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| 130 | #endif /* _LINUX_OBJTOOL_H */ |
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| 131 | |
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