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1 | #ifndef _LINUX_BUG_H | |
2 | #define _LINUX_BUG_H | |
3 | ||
4 | #include <asm/bug.h> | |
5 | #include <linux/compiler.h> | |
6 | ||
7 | enum bug_trap_type { | |
8 | BUG_TRAP_TYPE_NONE = 0, | |
9 | BUG_TRAP_TYPE_WARN = 1, | |
10 | BUG_TRAP_TYPE_BUG = 2, | |
11 | }; | |
12 | ||
13 | struct pt_regs; | |
14 | ||
15 | #ifdef __CHECKER__ | |
16 | #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) | |
17 | #define BUILD_BUG_ON_NOT_POWER_OF_2(n) (0) | |
18 | #define BUILD_BUG_ON_ZERO(e) (0) | |
19 | #define BUILD_BUG_ON_NULL(e) ((void*)0) | |
20 | #define BUILD_BUG_ON_INVALID(e) (0) | |
21 | #define BUILD_BUG_ON_MSG(cond, msg) (0) | |
22 | #define BUILD_BUG_ON(condition) (0) | |
23 | #define BUILD_BUG() (0) | |
24 | #define MAYBE_BUILD_BUG_ON(cond) (0) | |
25 | #else /* __CHECKER__ */ | |
26 | ||
27 | /* Force a compilation error if a constant expression is not a power of 2 */ | |
28 | #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \ | |
29 | BUILD_BUG_ON(((n) & ((n) - 1)) != 0) | |
30 | #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \ | |
31 | BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0)) | |
32 | ||
33 | /* Force a compilation error if condition is true, but also produce a | |
34 | result (of value 0 and type size_t), so the expression can be used | |
35 | e.g. in a structure initializer (or where-ever else comma expressions | |
36 | aren't permitted). */ | |
37 | #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) | |
38 | #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) | |
39 | ||
40 | /* | |
41 | * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the | |
42 | * expression but avoids the generation of any code, even if that expression | |
43 | * has side-effects. | |
44 | */ | |
45 | #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e)))) | |
46 | ||
47 | /** | |
48 | * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied | |
49 | * error message. | |
50 | * @condition: the condition which the compiler should know is false. | |
51 | * | |
52 | * See BUILD_BUG_ON for description. | |
53 | */ | |
54 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) | |
55 | ||
56 | /** | |
57 | * BUILD_BUG_ON - break compile if a condition is true. | |
58 | * @condition: the condition which the compiler should know is false. | |
59 | * | |
60 | * If you have some code which relies on certain constants being equal, or | |
61 | * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to | |
62 | * detect if someone changes it. | |
63 | * | |
64 | * The implementation uses gcc's reluctance to create a negative array, but gcc | |
65 | * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to | |
66 | * inline functions). Luckily, in 4.3 they added the "error" function | |
67 | * attribute just for this type of case. Thus, we use a negative sized array | |
68 | * (should always create an error on gcc versions older than 4.4) and then call | |
69 | * an undefined function with the error attribute (should always create an | |
70 | * error on gcc 4.3 and later). If for some reason, neither creates a | |
71 | * compile-time error, we'll still have a link-time error, which is harder to | |
72 | * track down. | |
73 | */ | |
74 | #ifndef __OPTIMIZE__ | |
75 | #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) | |
76 | #else | |
77 | #define BUILD_BUG_ON(condition) \ | |
78 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) | |
79 | #endif | |
80 | ||
81 | /** | |
82 | * BUILD_BUG - break compile if used. | |
83 | * | |
84 | * If you have some code that you expect the compiler to eliminate at | |
85 | * build time, you should use BUILD_BUG to detect if it is | |
86 | * unexpectedly used. | |
87 | */ | |
88 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") | |
89 | ||
90 | #define MAYBE_BUILD_BUG_ON(cond) \ | |
91 | do { \ | |
92 | if (__builtin_constant_p((cond))) \ | |
93 | BUILD_BUG_ON(cond); \ | |
94 | else \ | |
95 | BUG_ON(cond); \ | |
96 | } while (0) | |
97 | ||
98 | #endif /* __CHECKER__ */ | |
99 | ||
100 | #ifdef CONFIG_GENERIC_BUG | |
101 | #include <asm-generic/bug.h> | |
102 | ||
103 | static inline int is_warning_bug(const struct bug_entry *bug) | |
104 | { | |
105 | return bug->flags & BUGFLAG_WARNING; | |
106 | } | |
107 | ||
108 | struct bug_entry *find_bug(unsigned long bugaddr); | |
109 | ||
110 | enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); | |
111 | ||
112 | /* These are defined by the architecture */ | |
113 | int is_valid_bugaddr(unsigned long addr); | |
114 | ||
115 | #else /* !CONFIG_GENERIC_BUG */ | |
116 | ||
117 | static inline enum bug_trap_type report_bug(unsigned long bug_addr, | |
118 | struct pt_regs *regs) | |
119 | { | |
120 | return BUG_TRAP_TYPE_BUG; | |
121 | } | |
122 | ||
123 | #endif /* CONFIG_GENERIC_BUG */ | |
124 | ||
125 | /* | |
126 | * Since detected data corruption should stop operation on the affected | |
127 | * structures. Return value must be checked and sanely acted on by caller. | |
128 | */ | |
129 | static inline __must_check bool check_data_corruption(bool v) { return v; } | |
130 | #define CHECK_DATA_CORRUPTION(condition, fmt, ...) \ | |
131 | check_data_corruption(({ \ | |
132 | bool corruption = unlikely(condition); \ | |
133 | if (corruption) { \ | |
134 | if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \ | |
135 | pr_err(fmt, ##__VA_ARGS__); \ | |
136 | BUG(); \ | |
137 | } else \ | |
138 | WARN(1, fmt, ##__VA_ARGS__); \ | |
139 | } \ | |
140 | corruption; \ | |
141 | })) | |
142 | ||
143 | #endif /* _LINUX_BUG_H */ |