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 /* 34 * Force a compilation error if condition is true, but also produce a 35 * result (of value 0 and type size_t), so the expression can be used 36 * e.g. in a structure initializer (or where-ever else comma expressions 37 * aren't permitted). 38 */ 39 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); })) 40 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); })) 41 42 /* 43 * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the 44 * expression but avoids the generation of any code, even if that expression 45 * has side-effects. 46 */ 47 #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e)))) 48 49 /** 50 * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied 51 * error message. 52 * @condition: the condition which the compiler should know is false. 53 * 54 * See BUILD_BUG_ON for description. 55 */ 56 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) 57 58 /** 59 * BUILD_BUG_ON - break compile if a condition is true. 60 * @condition: the condition which the compiler should know is false. 61 * 62 * If you have some code which relies on certain constants being equal, or 63 * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to 64 * detect if someone changes it. 65 * 66 * The implementation uses gcc's reluctance to create a negative array, but gcc 67 * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to 68 * inline functions). Luckily, in 4.3 they added the "error" function 69 * attribute just for this type of case. Thus, we use a negative sized array 70 * (should always create an error on gcc versions older than 4.4) and then call 71 * an undefined function with the error attribute (should always create an 72 * error on gcc 4.3 and later). If for some reason, neither creates a 73 * compile-time error, we'll still have a link-time error, which is harder to 74 * track down. 75 */ 76 #ifndef __OPTIMIZE__ 77 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) 78 #else 79 #define BUILD_BUG_ON(condition) \ 80 BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) 81 #endif 82 83 /** 84 * BUILD_BUG - break compile if used. 85 * 86 * If you have some code that you expect the compiler to eliminate at 87 * build time, you should use BUILD_BUG to detect if it is 88 * unexpectedly used. 89 */ 90 #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed") 91 92 #define MAYBE_BUILD_BUG_ON(cond) \ 93 do { \ 94 if (__builtin_constant_p((cond))) \ 95 BUILD_BUG_ON(cond); \ 96 else \ 97 BUG_ON(cond); \ 98 } while (0) 99 100 #endif /* __CHECKER__ */ 101 102 #ifdef CONFIG_GENERIC_BUG 103 #include <asm-generic/bug.h> 104 105 static inline int is_warning_bug(const struct bug_entry *bug) 106 { 107 return bug->flags & BUGFLAG_WARNING; 108 } 109 110 struct bug_entry *find_bug(unsigned long bugaddr); 111 112 enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); 113 114 /* These are defined by the architecture */ 115 int is_valid_bugaddr(unsigned long addr); 116 117 #else /* !CONFIG_GENERIC_BUG */ 118 119 static inline enum bug_trap_type report_bug(unsigned long bug_addr, 120 struct pt_regs *regs) 121 { 122 return BUG_TRAP_TYPE_BUG; 123 } 124 125 #endif /* CONFIG_GENERIC_BUG */ 126 127 /* 128 * Since detected data corruption should stop operation on the affected 129 * structures. Return value must be checked and sanely acted on by caller. 130 */ 131 static inline __must_check bool check_data_corruption(bool v) { return v; } 132 #define CHECK_DATA_CORRUPTION(condition, fmt, ...) \ 133 check_data_corruption(({ \ 134 bool corruption = unlikely(condition); \ 135 if (corruption) { \ 136 if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \ 137 pr_err(fmt, ##__VA_ARGS__); \ 138 BUG(); \ 139 } else \ 140 WARN(1, fmt, ##__VA_ARGS__); \ 141 } \ 142 corruption; \ 143 })) 144 145 #endif /* _LINUX_BUG_H */ 146