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 end=0 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 .byte \end 39 .balign 4 40 .popsection 41 #endif 42 .endm 43 44 .macro UNWIND_HINT_EMPTY 45 UNWIND_HINT sp_reg=ORC_REG_UNDEFINED end=1 46 .endm 47 48 .macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0 49 .if \base == %rsp 50 .if \indirect 51 .set sp_reg, ORC_REG_SP_INDIRECT 52 .else 53 .set sp_reg, ORC_REG_SP 54 .endif 55 .elseif \base == %rbp 56 .set sp_reg, ORC_REG_BP 57 .elseif \base == %rdi 58 .set sp_reg, ORC_REG_DI 59 .elseif \base == %rdx 60 .set sp_reg, ORC_REG_DX 61 .elseif \base == %r10 62 .set sp_reg, ORC_REG_R10 63 .else 64 .error "UNWIND_HINT_REGS: bad base register" 65 .endif 66 67 .set sp_offset, \offset 68 69 .if \iret 70 .set type, ORC_TYPE_REGS_IRET 71 .elseif \extra == 0 72 .set type, ORC_TYPE_REGS_IRET 73 .set sp_offset, \offset + (16*8) 74 .else 75 .set type, ORC_TYPE_REGS 76 .endif 77 78 UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type 79 .endm 80 81 .macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 82 UNWIND_HINT_REGS base=\base offset=\offset iret=1 83 .endm 84 85 .macro UNWIND_HINT_FUNC sp_offset=8 86 UNWIND_HINT sp_offset=\sp_offset 87 .endm 88 89 #else /* !__ASSEMBLY__ */ 90 91 #define UNWIND_HINT(sp_reg, sp_offset, type, end) \ 92 "987: \n\t" \ 93 ".pushsection .discard.unwind_hints\n\t" \ 94 /* struct unwind_hint */ \ 95 ".long 987b - .\n\t" \ 96 ".short " __stringify(sp_offset) "\n\t" \ 97 ".byte " __stringify(sp_reg) "\n\t" \ 98 ".byte " __stringify(type) "\n\t" \ 99 ".byte " __stringify(end) "\n\t" \ 100 ".balign 4 \n\t" \ 101 ".popsection\n\t" 102 103 #define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE, 0) 104 #define UNWIND_HINT_EMPTY 105 #define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE, 0) 106 107 #endif /* __ASSEMBLY__ */ 108 109 #endif /* _ASM_X86_UNWIND_HINTS_H */ 110