1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_OBJTOOL_H |
3 | #define _LINUX_OBJTOOL_H |
4 | |
5 | #include <linux/objtool_types.h> |
6 | |
7 | #ifdef CONFIG_OBJTOOL |
8 | |
9 | #include <asm/asm.h> |
10 | |
11 | #ifndef __ASSEMBLY__ |
12 | |
13 | #define UNWIND_HINT(type, sp_reg, sp_offset, signal) \ |
14 | "987: \n\t" \ |
15 | ".pushsection .discard.unwind_hints\n\t" \ |
16 | /* struct unwind_hint */ \ |
17 | ".long 987b - .\n\t" \ |
18 | ".short " __stringify(sp_offset) "\n\t" \ |
19 | ".byte " __stringify(sp_reg) "\n\t" \ |
20 | ".byte " __stringify(type) "\n\t" \ |
21 | ".byte " __stringify(signal) "\n\t" \ |
22 | ".balign 4 \n\t" \ |
23 | ".popsection\n\t" |
24 | |
25 | /* |
26 | * This macro marks the given function's stack frame as "non-standard", which |
27 | * tells objtool to ignore the function when doing stack metadata validation. |
28 | * It should only be used in special cases where you're 100% sure it won't |
29 | * affect the reliability of frame pointers and kernel stack traces. |
30 | * |
31 | * For more information, see tools/objtool/Documentation/objtool.txt. |
32 | */ |
33 | #define STACK_FRAME_NON_STANDARD(func) \ |
34 | static void __used __section(".discard.func_stack_frame_non_standard") \ |
35 | *__func_stack_frame_non_standard_##func = func |
36 | |
37 | /* |
38 | * STACK_FRAME_NON_STANDARD_FP() is a frame-pointer-specific function ignore |
39 | * for the case where a function is intentionally missing frame pointer setup, |
40 | * but otherwise needs objtool/ORC coverage when frame pointers are disabled. |
41 | */ |
42 | #ifdef CONFIG_FRAME_POINTER |
43 | #define STACK_FRAME_NON_STANDARD_FP(func) STACK_FRAME_NON_STANDARD(func) |
44 | #else |
45 | #define STACK_FRAME_NON_STANDARD_FP(func) |
46 | #endif |
47 | |
48 | #define ANNOTATE_NOENDBR \ |
49 | "986: \n\t" \ |
50 | ".pushsection .discard.noendbr\n\t" \ |
51 | ".long 986b\n\t" \ |
52 | ".popsection\n\t" |
53 | |
54 | #define ASM_REACHABLE \ |
55 | "998:\n\t" \ |
56 | ".pushsection .discard.reachable\n\t" \ |
57 | ".long 998b\n\t" \ |
58 | ".popsection\n\t" |
59 | |
60 | #else /* __ASSEMBLY__ */ |
61 | |
62 | /* |
63 | * This macro indicates that the following intra-function call is valid. |
64 | * Any non-annotated intra-function call will cause objtool to issue a warning. |
65 | */ |
66 | #define ANNOTATE_INTRA_FUNCTION_CALL \ |
67 | 999: \ |
68 | .pushsection .discard.intra_function_calls; \ |
69 | .long 999b; \ |
70 | .popsection; |
71 | |
72 | /* |
73 | * In asm, there are two kinds of code: normal C-type callable functions and |
74 | * the rest. The normal callable functions can be called by other code, and |
75 | * don't do anything unusual with the stack. Such normal callable functions |
76 | * are annotated with the ENTRY/ENDPROC macros. Most asm code falls in this |
77 | * category. In this case, no special debugging annotations are needed because |
78 | * objtool can automatically generate the ORC data for the ORC unwinder to read |
79 | * at runtime. |
80 | * |
81 | * Anything which doesn't fall into the above category, such as syscall and |
82 | * interrupt handlers, tends to not be called directly by other functions, and |
83 | * often does unusual non-C-function-type things with the stack pointer. Such |
84 | * code needs to be annotated such that objtool can understand it. The |
85 | * following CFI hint macros are for this type of code. |
86 | * |
87 | * These macros provide hints to objtool about the state of the stack at each |
88 | * instruction. Objtool starts from the hints and follows the code flow, |
89 | * making automatic CFI adjustments when it sees pushes and pops, filling out |
90 | * the debuginfo as necessary. It will also warn if it sees any |
91 | * inconsistencies. |
92 | */ |
93 | .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 |
94 | .Lhere_\@: |
95 | .pushsection .discard.unwind_hints |
96 | /* struct unwind_hint */ |
97 | .long .Lhere_\@ - . |
98 | .short \sp_offset |
99 | .byte \sp_reg |
100 | .byte \type |
101 | .byte \signal |
102 | .balign 4 |
103 | .popsection |
104 | .endm |
105 | |
106 | .macro STACK_FRAME_NON_STANDARD func:req |
107 | .pushsection .discard.func_stack_frame_non_standard, "aw" |
108 | .long \func - . |
109 | .popsection |
110 | .endm |
111 | |
112 | .macro STACK_FRAME_NON_STANDARD_FP func:req |
113 | #ifdef CONFIG_FRAME_POINTER |
114 | STACK_FRAME_NON_STANDARD \func |
115 | #endif |
116 | .endm |
117 | |
118 | .macro ANNOTATE_NOENDBR |
119 | .Lhere_\@: |
120 | .pushsection .discard.noendbr |
121 | .long .Lhere_\@ |
122 | .popsection |
123 | .endm |
124 | |
125 | /* |
126 | * Use objtool to validate the entry requirement that all code paths do |
127 | * VALIDATE_UNRET_END before RET. |
128 | * |
129 | * NOTE: The macro must be used at the beginning of a global symbol, otherwise |
130 | * it will be ignored. |
131 | */ |
132 | .macro VALIDATE_UNRET_BEGIN |
133 | #if defined(CONFIG_NOINSTR_VALIDATION) && \ |
134 | (defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_SRSO)) |
135 | .Lhere_\@: |
136 | .pushsection .discard.validate_unret |
137 | .long .Lhere_\@ - . |
138 | .popsection |
139 | #endif |
140 | .endm |
141 | |
142 | .macro REACHABLE |
143 | .Lhere_\@: |
144 | .pushsection .discard.reachable |
145 | .long .Lhere_\@ |
146 | .popsection |
147 | .endm |
148 | |
149 | #endif /* __ASSEMBLY__ */ |
150 | |
151 | #else /* !CONFIG_OBJTOOL */ |
152 | |
153 | #ifndef __ASSEMBLY__ |
154 | |
155 | #define UNWIND_HINT(type, sp_reg, sp_offset, signal) "\n\t" |
156 | #define STACK_FRAME_NON_STANDARD(func) |
157 | #define STACK_FRAME_NON_STANDARD_FP(func) |
158 | #define ANNOTATE_NOENDBR |
159 | #define ASM_REACHABLE |
160 | #else |
161 | #define ANNOTATE_INTRA_FUNCTION_CALL |
162 | .macro UNWIND_HINT type:req sp_reg=0 sp_offset=0 signal=0 |
163 | .endm |
164 | .macro STACK_FRAME_NON_STANDARD func:req |
165 | .endm |
166 | .macro ANNOTATE_NOENDBR |
167 | .endm |
168 | .macro REACHABLE |
169 | .endm |
170 | #endif |
171 | |
172 | #endif /* CONFIG_OBJTOOL */ |
173 | |
174 | #endif /* _LINUX_OBJTOOL_H */ |
175 | |