diff options
Diffstat (limited to 'arch/x86/include/asm/unwind_hints.h')
| -rw-r--r-- | arch/x86/include/asm/unwind_hints.h | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/arch/x86/include/asm/unwind_hints.h b/arch/x86/include/asm/unwind_hints.h new file mode 100644 index 000000000..0bcdb1279 --- /dev/null +++ b/arch/x86/include/asm/unwind_hints.h @@ -0,0 +1,109 @@ +#ifndef _ASM_X86_UNWIND_HINTS_H +#define _ASM_X86_UNWIND_HINTS_H + +#include "orc_types.h" + +#ifdef __ASSEMBLY__ + +/* + * In asm, there are two kinds of code: normal C-type callable functions and + * the rest. The normal callable functions can be called by other code, and + * don't do anything unusual with the stack. Such normal callable functions + * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this + * category. In this case, no special debugging annotations are needed because + * objtool can automatically generate the ORC data for the ORC unwinder to read + * at runtime. + * + * Anything which doesn't fall into the above category, such as syscall and + * interrupt handlers, tends to not be called directly by other functions, and + * often does unusual non-C-function-type things with the stack pointer. Such + * code needs to be annotated such that objtool can understand it. The + * following CFI hint macros are for this type of code. + * + * These macros provide hints to objtool about the state of the stack at each + * instruction. Objtool starts from the hints and follows the code flow, + * making automatic CFI adjustments when it sees pushes and pops, filling out + * the debuginfo as necessary. It will also warn if it sees any + * inconsistencies. + */ +.macro UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=0 type=ORC_TYPE_CALL end=0 +#ifdef CONFIG_STACK_VALIDATION +.Lunwind_hint_ip_\@: + .pushsection .discard.unwind_hints + /* struct unwind_hint */ + .long .Lunwind_hint_ip_\@ - . + .short \sp_offset + .byte \sp_reg + .byte \type + .byte \end + .balign 4 + .popsection +#endif +.endm + +.macro UNWIND_HINT_EMPTY + UNWIND_HINT sp_reg=ORC_REG_UNDEFINED end=1 +.endm + +.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 iret=0 + .if \base == %rsp + .if \indirect + .set sp_reg, ORC_REG_SP_INDIRECT + .else + .set sp_reg, ORC_REG_SP + .endif + .elseif \base == %rbp + .set sp_reg, ORC_REG_BP + .elseif \base == %rdi + .set sp_reg, ORC_REG_DI + .elseif \base == %rdx + .set sp_reg, ORC_REG_DX + .elseif \base == %r10 + .set sp_reg, ORC_REG_R10 + .else + .error "UNWIND_HINT_REGS: bad base register" + .endif + + .set sp_offset, \offset + + .if \iret + .set type, ORC_TYPE_REGS_IRET + .elseif \extra == 0 + .set type, ORC_TYPE_REGS_IRET + .set sp_offset, \offset + (16*8) + .else + .set type, ORC_TYPE_REGS + .endif + + UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type +.endm + +.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0 + UNWIND_HINT_REGS base=\base offset=\offset iret=1 +.endm + +.macro UNWIND_HINT_FUNC sp_offset=8 + UNWIND_HINT sp_offset=\sp_offset +.endm + +#else /* !__ASSEMBLY__ */ + +#define UNWIND_HINT(sp_reg, sp_offset, type, end) \ + "987: \n\t" \ + ".pushsection .discard.unwind_hints\n\t" \ + /* struct unwind_hint */ \ + ".long 987b - .\n\t" \ + ".short " __stringify(sp_offset) "\n\t" \ + ".byte " __stringify(sp_reg) "\n\t" \ + ".byte " __stringify(type) "\n\t" \ + ".byte " __stringify(end) "\n\t" \ + ".balign 4 \n\t" \ + ".popsection\n\t" + +#define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE, 0) + +#define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE, 0) + +#endif /* __ASSEMBLY__ */ + +#endif /* _ASM_X86_UNWIND_HINTS_H */ |