include/linux/bug.h

   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, this returns false if the corruption condition is found.
 128  */
 129 #define CHECK_DATA_CORRUPTION(condition, fmt, ...)                       \
 130         do {                                                             \
 131                 if (unlikely(condition)) {                               \
 132                         if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
 133                                 pr_err(fmt, ##__VA_ARGS__);              \
 134                                 BUG();                                   \
 135                         } else                                           \
 136                                 WARN(1, fmt, ##__VA_ARGS__);             \
 137                         return false;                                    \
 138                 }                                                        \
 139         } while (0)
 140
 141 #endif  /* _LINUX_BUG_H */