1 #ifndef _ASM_X86_UNWIND_HINTS_H
2 #define _ASM_X86_UNWIND_HINTS_H
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
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.
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
29 .macro UNWIND_HINT sp_reg
=ORC_REG_SP sp_offset
=0 type
=ORC_TYPE_CALL
30 #ifdef CONFIG_STACK_VALIDATION
32 .pushsection
.discard
.unwind_hints
33 /* struct unwind_hint */
34 .long .Lunwind_hint_ip_\@
- .
42 .macro UNWIND_HINT_EMPTY
43 UNWIND_HINT sp_reg
=ORC_REG_UNDEFINED
46 .macro UNWIND_HINT_REGS base
=%rsp offset
=0 indirect
=0 extra
=1 iret
=0
49 .set sp_reg
, ORC_REG_SP_INDIRECT
51 .set sp_reg
, ORC_REG_SP
54 .set sp_reg
, ORC_REG_BP
56 .set sp_reg
, ORC_REG_DI
58 .set sp_reg
, ORC_REG_DX
60 .set sp_reg
, ORC_REG_R10
62 .error
"UNWIND_HINT_REGS: bad base register"
65 .set sp_offset
, \offset
68 .set type
, ORC_TYPE_REGS_IRET
70 .set type
, ORC_TYPE_REGS_IRET
71 .set sp_offset
, \offset
+ (16*8)
73 .set type
, ORC_TYPE_REGS
76 UNWIND_HINT sp_reg
=sp_reg sp_offset
=sp_offset type
=type
79 .macro UNWIND_HINT_IRET_REGS base
=%rsp offset
=0
80 UNWIND_HINT_REGS base
=\base offset
=\offset iret
=1
83 .macro UNWIND_HINT_FUNC sp_offset
=8
84 UNWIND_HINT sp_offset
=\sp_offset
87 #else /* !__ASSEMBLY__ */
89 #define UNWIND_HINT(sp_reg, sp_offset, type) \
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" \
99 #define UNWIND_HINT_SAVE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_SAVE)
101 #define UNWIND_HINT_RESTORE UNWIND_HINT(0, 0, UNWIND_HINT_TYPE_RESTORE)
103 #endif /* __ASSEMBLY__ */
105 #endif /* _ASM_X86_UNWIND_HINTS_H */