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
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