1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _ASM_X86_FRAME_H |
3 | #define _ASM_X86_FRAME_H |
4 | |
5 | #include <asm/asm.h> |
6 | |
7 | /* |
8 | * These are stack frame creation macros. They should be used by every |
9 | * callable non-leaf asm function to make kernel stack traces more reliable. |
10 | */ |
11 | |
12 | #ifdef CONFIG_FRAME_POINTER |
13 | |
14 | #ifdef __ASSEMBLY__ |
15 | |
16 | .macro FRAME_BEGIN |
17 | push %_ASM_BP |
18 | _ASM_MOV %_ASM_SP, %_ASM_BP |
19 | .endm |
20 | |
21 | .macro FRAME_END |
22 | pop %_ASM_BP |
23 | .endm |
24 | |
25 | #ifdef CONFIG_X86_64 |
26 | /* |
27 | * This is a sneaky trick to help the unwinder find pt_regs on the stack. The |
28 | * frame pointer is replaced with an encoded pointer to pt_regs. The encoding |
29 | * is just setting the LSB, which makes it an invalid stack address and is also |
30 | * a signal to the unwinder that it's a pt_regs pointer in disguise. |
31 | * |
32 | * NOTE: This macro must be used *after* PUSH_AND_CLEAR_REGS because it corrupts |
33 | * the original rbp. |
34 | */ |
35 | .macro ENCODE_FRAME_POINTER ptregs_offset=0 |
36 | leaq 1+\ptregs_offset(%rsp), %rbp |
37 | .endm |
38 | #else /* !CONFIG_X86_64 */ |
39 | /* |
40 | * This is a sneaky trick to help the unwinder find pt_regs on the stack. The |
41 | * frame pointer is replaced with an encoded pointer to pt_regs. The encoding |
42 | * is just clearing the MSB, which makes it an invalid stack address and is also |
43 | * a signal to the unwinder that it's a pt_regs pointer in disguise. |
44 | * |
45 | * NOTE: This macro must be used *after* SAVE_ALL because it corrupts the |
46 | * original ebp. |
47 | */ |
48 | .macro ENCODE_FRAME_POINTER |
49 | mov %esp, %ebp |
50 | andl $0x7fffffff, %ebp |
51 | .endm |
52 | #endif /* CONFIG_X86_64 */ |
53 | |
54 | #else /* !__ASSEMBLY__ */ |
55 | |
56 | #define FRAME_BEGIN \ |
57 | "push %" _ASM_BP "\n" \ |
58 | _ASM_MOV "%" _ASM_SP ", %" _ASM_BP "\n" |
59 | |
60 | #define FRAME_END "pop %" _ASM_BP "\n" |
61 | |
62 | #ifdef CONFIG_X86_64 |
63 | |
64 | #define ENCODE_FRAME_POINTER \ |
65 | "lea 1(%rsp), %rbp\n\t" |
66 | |
67 | static inline unsigned long encode_frame_pointer(struct pt_regs *regs) |
68 | { |
69 | return (unsigned long)regs + 1; |
70 | } |
71 | |
72 | #else /* !CONFIG_X86_64 */ |
73 | |
74 | #define ENCODE_FRAME_POINTER \ |
75 | "movl %esp, %ebp\n\t" \ |
76 | "andl $0x7fffffff, %ebp\n\t" |
77 | |
78 | static inline unsigned long encode_frame_pointer(struct pt_regs *regs) |
79 | { |
80 | return (unsigned long)regs & 0x7fffffff; |
81 | } |
82 | |
83 | #endif /* CONFIG_X86_64 */ |
84 | |
85 | #endif /* __ASSEMBLY__ */ |
86 | |
87 | #define FRAME_OFFSET __ASM_SEL(4, 8) |
88 | |
89 | #else /* !CONFIG_FRAME_POINTER */ |
90 | |
91 | #ifdef __ASSEMBLY__ |
92 | |
93 | .macro ENCODE_FRAME_POINTER ptregs_offset=0 |
94 | .endm |
95 | |
96 | #else /* !__ASSEMBLY */ |
97 | |
98 | #define ENCODE_FRAME_POINTER |
99 | |
100 | static inline unsigned long encode_frame_pointer(struct pt_regs *regs) |
101 | { |
102 | return 0; |
103 | } |
104 | |
105 | #endif |
106 | |
107 | #define FRAME_BEGIN |
108 | #define FRAME_END |
109 | #define FRAME_OFFSET 0 |
110 | |
111 | #endif /* CONFIG_FRAME_POINTER */ |
112 | |
113 | #endif /* _ASM_X86_FRAME_H */ |
114 | |