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