| 1 |
|
| 2 | #ifndef _LINUX_OBJTOOL_H
|
| 3 | #define _LINUX_OBJTOOL_H
|
| 4 |
|
| 5 | #ifndef __ASSEMBLY__
|
| 6 |
|
| 7 | #include <linux/types.h>
|
| 8 |
|
| 9 | |
| 10 | * This struct is used by asm and inline asm code to manually annotate the
|
| 11 | * location of registers on the stack.
|
| 12 |
|
| 13 | struct unwind_hint {
|
| 14 | u32 ip;
|
| 15 | s16 sp_offset;
|
| 16 | u8 sp_reg;
|
| 17 | u8 type;
|
| 18 | u8 signal;
|
| 19 | u8 end;
|
| 20 | };
|
| 21 | #endif
|
| 22 |
|
| 23 | |
| 24 | * UNWIND_HINT_TYPE_CALL: Indicates that sp_reg+sp_offset resolves to PREV_SP
|
| 25 | * (the caller's SP right before it made the call). Used for all callable
|
| 26 | * functions, i.e. all C code and all callable asm functions.
|
| 27 | *
|
| 28 | * UNWIND_HINT_TYPE_REGS: Used in entry code to indicate that sp_reg+sp_offset
|
| 29 | * points to a fully populated pt_regs from a syscall, interrupt, or exception.
|
| 30 | *
|
| 31 | * UNWIND_HINT_TYPE_REGS_PARTIAL: Used in entry code to indicate that
|
| 32 | * sp_reg+sp_offset points to the iret return frame.
|
| 33 | *
|
| 34 | * UNWIND_HINT_FUNC: Generate the unwind metadata of a callable function.
|
| 35 | * Useful for code which doesn't have an ELF function annotation.
|
| 36 | *
|
| 37 | * UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
|
| 38 |
|
| 39 | #define UNWIND_HINT_TYPE_CALL 0
|
| 40 | #define UNWIND_HINT_TYPE_REGS 1
|
| 41 | #define UNWIND_HINT_TYPE_REGS_PARTIAL 2
|
| 42 | #define UNWIND_HINT_TYPE_FUNC 3
|
| 43 | #define UNWIND_HINT_TYPE_ENTRY 4
|
| 44 | #define UNWIND_HINT_TYPE_SAVE 5
|
| 45 | #define UNWIND_HINT_TYPE_RESTORE 6
|
| 46 |
|
| 47 | #ifdef CONFIG_OBJTOOL
|
| 48 |
|
| 49 | #include <asm/asm.h>
|
| 50 |
|
| 51 | #ifndef __ASSEMBLY__
|
| 52 |
|
| 53 | #define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
|
| 54 | "987: \n\t" \
|
| 55 | ".pushsection .discard.unwind_hints\n\t" \
|
| 56 | \
|
| 57 | ".long 987b - .\n\t" \
|
| 58 | ".short " __stringify(sp_offset) "\n\t" \
|
| 59 | ".byte " __stringify(sp_reg) "\n\t" \
|
| 60 | ".byte " __stringify(type) "\n\t" \
|
| 61 | ".byte " __stringify(signal) "\n\t" \
|
| 62 | ".byte " __stringify(end) "\n\t" \
|
| 63 | ".balign 4 \n\t" \
|
| 64 | ".popsection\n\t"
|
| 65 |
|
| 66 | |
| 67 | * This macro marks the given function's stack frame as "non-standard", which
|
| 68 | * tells objtool to ignore the function when doing stack metadata validation.
|
| 69 | * It should only be used in special cases where you're 100% sure it won't
|
| 70 | * affect the reliability of frame pointers and kernel stack traces.
|
| 71 | *
|
| 72 | * For more information, see tools/objtool/Documentation/objtool.txt.
|
| 73 |
|
| 74 | #define STACK_FRAME_NON_STANDARD(func) \
|
| 75 | static void __used __section(".discard.func_stack_frame_non_standard") \
|
| 76 | *__func_stack_frame_non_standard_##func = func
|
| 77 |
|
| 78 | |
| 79 | * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore
|
| 80 | * for the case where a function is intentionally missing frame pointer setup,
|
| 81 | * but otherwise needs objtool/ORC coverage when frame pointers are disabled.
|
| 82 |
|
| 83 | #ifdef CONFIG_FRAME_POINTER
|
| 84 | #define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func)
|
| 85 | #else
|
| 86 | #define STACK_FRAME_NON_STANDARD_FP(func)
|
| 87 | #endif
|
| 88 |
|
| 89 | #define ANNOTATE_NOENDBR \
|
| 90 | "986: \n\t" \
|
| 91 | ".pushsection .discard.noendbr\n\t" \
|
| 92 | _ASM_PTR " 986b\n\t" \
|
| 93 | ".popsection\n\t"
|
| 94 |
|
| 95 | #define ASM_REACHABLE \
|
| 96 | "998:\n\t" \
|
| 97 | ".pushsection .discard.reachable\n\t" \
|
| 98 | ".long 998b - .\n\t" \
|
| 99 | ".popsection\n\t"
|
| 100 |
|
| 101 | #else
|
| 102 |
|
| 103 | |
| 104 | * This macro indicates that the following intra-function call is valid.
|
| 105 | * Any non-annotated intra-function call will cause objtool to issue a warning.
|
| 106 |
|
| 107 | #define ANNOTATE_INTRA_FUNCTION_CALL \
|
| 108 | 999: \
|
| 109 | .pushsection .discard.intra_function_calls; \
|
| 110 | .long 999b; \
|
| 111 | .popsection;
|
| 112 |
|
| 113 | |
| 114 | * In asm, there are two kinds of code: normal C-type callable functions and
|
| 115 | * the rest. The normal callable functions can be called by other code, and
|
| 116 | * don't do anything unusual with the stack. Such normal callable functions
|
| 117 | * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this
|
| 118 | * category. In this case, no special debugging annotations are needed because
|
| 119 | * objtool can automatically generate the ORC data for the ORC unwinder to read
|
| 120 | * at runtime.
|
| 121 | *
|
| 122 | * Anything which doesn't fall into the above category, such as syscall and
|
| 123 | * interrupt handlers, tends to not be called directly by other functions, and
|
| 124 | * often does unusual non-C-function-type things with the stack pointer. Such
|
| 125 | * code needs to be annotated such that objtool can understand it. The
|
| 126 | * following CFI hint macros are for this type of code.
|
| 127 | *
|
| 128 | * These macros provide hints to objtool about the state of the stack at each
|
| 129 | * instruction. Objtool starts from the hints and follows the code flow,
|
| 130 | * making automatic CFI adjustments when it sees pushes and pops, filling out
|
| 131 | * the debuginfo as necessary. It will also warn if it sees any
|
| 132 | * inconsistencies.
|
| 133 |
|
| 134 | .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
|
| 135 | .Lunwind_hint_ip_\@:
|
| 136 | .pushsection .discard.unwind_hints
|
| 137 |
|
| 138 | .long .Lunwind_hint_ip_\@ - .
|
| 139 | .short \sp_offset
|
| 140 | .byte \sp_reg
|
| 141 | .byte \type
|
| 142 | .byte \signal
|
| 143 | .byte \end
|
| 144 | .balign 4
|
| 145 | .popsection
|
| 146 | .endm
|
| 147 |
|
| 148 | .macro STACK_FRAME_NON_STANDARD func:req
|
| 149 | .pushsection .discard.func_stack_frame_non_standard, "aw"
|
| 150 | _ASM_PTR \func
|
| 151 | .popsection
|
| 152 | .endm
|
| 153 |
|
| 154 | .macro STACK_FRAME_NON_STANDARD_FP func:req
|
| 155 | #ifdef CONFIG_FRAME_POINTER
|
| 156 | STACK_FRAME_NON_STANDARD \func
|
| 157 | #endif
|
| 158 | .endm
|
| 159 |
|
| 160 | .macro ANNOTATE_NOENDBR
|
| 161 | .Lhere_\@:
|
| 162 | .pushsection .discard.noendbr
|
| 163 | .quad .Lhere_\@
|
| 164 | .popsection
|
| 165 | .endm
|
| 166 |
|
| 167 | .macro REACHABLE
|
| 168 | .Lhere_\@:
|
| 169 | .pushsection .discard.reachable
|
| 170 | .long .Lhere_\@ - .
|
| 171 | .popsection
|
| 172 | .endm
|
| 173 |
|
| 174 | #endif
|
| 175 |
|
| 176 | #else
|
| 177 |
|
| 178 | #ifndef __ASSEMBLY__
|
| 179 |
|
| 180 | #define UNWIND_HINT(sp_reg, sp_offset, type, signal, end) \
|
| 181 | "\n\t"
|
| 182 | #define STACK_FRAME_NON_STANDARD(func)
|
| 183 | #define STACK_FRAME_NON_STANDARD_FP(func)
|
| 184 | #define ANNOTATE_NOENDBR
|
| 185 | #define ASM_REACHABLE
|
| 186 | #else
|
| 187 | #define ANNOTATE_INTRA_FUNCTION_CALL
|
| 188 | .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 end=0
|
| 189 | .endm
|
| 190 | .macro STACK_FRAME_NON_STANDARD func:req
|
| 191 | .endm
|
| 192 | .macro ANNOTATE_NOENDBR
|
| 193 | .endm
|
| 194 | .macro REACHABLE
|
| 195 | .endm
|
| 196 | #endif
|
| 197 |
|
| 198 | #endif
|
| 199 |
|
| 200 | #endif
|