1 #ifndef _ASM_X86_UNWIND_HINTS_H 2 #define _ASM_X86_UNWIND_HINTS_H 3 4 #include "orc_types.h" 5 6 #ifdef __ASSEMBLY__ 7 8 /* 9 * In asm, there are two kinds of code: normal C-type callable functions and 10 * the rest. The normal callable functions can be called by other code, and 11 * don't do anything unusual with the stack. Such normal callable functions 12 * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this 13 * category. In this case, no special debugging annotations are needed because 14 * objtool can automatically generate the ORC data for the ORC unwinder to read 15 * at runtime. 16 * 17 * Anything which doesn't fall into the above category, such as syscall and 18 * interrupt handlers, tends to not be called directly by other functions, and 19 * often does unusual non-C-function-type things with the stack pointer. Such 20 * code needs to be annotated such that objtool can understand it. The 21 * following CFI hint macros are for this type of code. 22 * 23 * These macros provide hints to objtool about the state of the stack at each 24 * instruction. Objtool starts from the hints and follows the code flow, 25 * making automatic CFI adjustments when it sees pushes and pops, filling out 26 * the debuginfo as necessary. It will also warn if it sees any 27 * inconsistencies. 28 */ 29 .macro UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL 30 #ifdef CONFIG_STACK_VALIDATION 31 .Lunwind_hint_ip_\@: 32 .pushsection .discard.unwind_hints 33 /* struct unwind_hint */ 34 .long .Lunwind_hint_ip_\@ - . 35 .short \sp_offset 36 .byte \sp_reg 37 .byte \type 38 .popsection 39 #endif 40 .endm 41 42 .macro UNWIND_HINT_EMPTY 43 UNWIND_HINT sp_reg=ORC_REG_UNDEFINED 44 .endm 45 46 .macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0 47 .if \base == %rsp 48 .if \indirect 49 .set sp_reg, ORC_REG_SP_INDIRECT 50 .else 51 .set sp_reg, ORC_REG_SP 52 .endif 53 .elseif \base == %rbp 54 .set sp_reg, ORC_REG_BP 55 .elseif \base == %rdi 56 .set sp_reg, ORC_REG_DI 57 .elseif \base == %rdx 58 .set sp_reg, ORC_REG_DX 59 .elseif \base == %r10 60 .set sp_reg, ORC_REG_R10 61 .else 62 .error "UNWIND_HINT_REGS: bad base register" 63 .endif 64 65 .set sp_offset, \offset 66 67 .if \iret 68 .set type, ORC_TYPE_REGS_IRET 69 .elseif \extra == 0 70 .set type, ORC_TYPE_REGS_IRET 71 .set sp_offset, \offset + (16*8) 72 .else 73 .set type, ORC_TYPE_REGS 74 .endif 75 76 UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type 77 .endm 78 79 .macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 80 UNWIND_HINT_REGS base=\base offset=\offset iret=1 81 .endm 82 83 .macro UNWIND_HINT_FUNC sp_offset=8 84 UNWIND_HINT sp_offset=\sp_offset 85 .endm 86 87 #else /* !__ASSEMBLY__ */ 88 89 #define UNWIND_HINT(sp_reg, sp_offset, type) \ 90 "987: \n\t" \ 91 ".pushsection .discard.unwind_hints\n\t" \ 92 /* struct unwind_hint */ \ 93 ".long 987b - .\n\t" \ 94 ".short " __stringify(sp_offset) "\n\t" \ 95 ".byte " __stringify(sp_reg) "\n\t" \ 96 ".byte " __stringify(type) "\n\t" \ 97 ".popsection\n\t" 98 99 #define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE) 100 101 #define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE) 102 103 #endif /* __ASSEMBLY__ */ 104 105 #endif /* _ASM_X86_UNWIND_HINTS_H */ 106