xref: /openbmc/linux/include/linux/bug.h (revision f7c35abe)
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 const 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 */
144