include/linux/bug.h

   1 #ifndef _LINUX_BUG_H
   2 #define _LINUX_BUG_H
   3
   4 #include <asm/bug.h>
   5
   6 enum bug_trap_type {
   7         BUG_TRAP_TYPE_NONE = 0,
   8         BUG_TRAP_TYPE_WARN = 1,
   9         BUG_TRAP_TYPE_BUG = 2,
  10 };
  11
  12 struct pt_regs;
  13
  14 #ifdef __CHECKER__
  15 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)
  16 #define BUILD_BUG_ON_ZERO(e) (0)
  17 #define BUILD_BUG_ON_NULL(e) ((void*)0)
  18 #define BUILD_BUG_ON_INVALID(e) (0)
  19 #define BUILD_BUG_ON(condition)
  20 #define BUILD_BUG() (0)
  21 #else /* __CHECKER__ */
  22
  23 /* Force a compilation error if a constant expression is not a power of 2 */
  24 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
  25         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
  26
  27 /* Force a compilation error if condition is true, but also produce a
  28    result (of value 0 and type size_t), so the expression can be used
  29    e.g. in a structure initializer (or where-ever else comma expressions
  30    aren't permitted). */
  31 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
  32 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  33
  34 /*
  35  * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
  36  * expression but avoids the generation of any code, even if that expression
  37  * has side-effects.
  38  */
  39 #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
  40
  41 /**
  42  * BUILD_BUG_ON - break compile if a condition is true.
  43  * @condition: the condition which the compiler should know is false.
  44  *
  45  * If you have some code which relies on certain constants being equal, or
  46  * other compile-time-evaluated condition, you should use BUILD_BUG_ON to
  47  * detect if someone changes it.
  48  *
  49  * The implementation uses gcc's reluctance to create a negative array, but
  50  * gcc (as of 4.4) only emits that error for obvious cases (eg. not arguments
  51  * to inline functions).  So as a fallback we use the optimizer; if it can't
  52  * prove the condition is false, it will cause a link error on the undefined
  53  * "__build_bug_on_failed".  This error message can be harder to track down
  54  * though, hence the two different methods.
  55  */
  56 #ifndef __OPTIMIZE__
  57 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
  58 #else
  59 extern int __build_bug_on_failed;
  60 #define BUILD_BUG_ON(condition)                                 \
  61         do {                                                    \
  62                 ((void)sizeof(char[1 - 2*!!(condition)]));      \
  63                 if (condition) __build_bug_on_failed = 1;       \
  64         } while(0)
  65 #endif
  66
  67 /**
  68  * BUILD_BUG - break compile if used.
  69  *
  70  * If you have some code that you expect the compiler to eliminate at
  71  * build time, you should use BUILD_BUG to detect if it is
  72  * unexpectedly used.
  73  */
  74 #define BUILD_BUG()                                             \
  75         do {                                                    \
  76                 extern void __build_bug_failed(void)            \
  77                         __linktime_error("BUILD_BUG failed");   \
  78                 __build_bug_failed();                           \
  79         } while (0)
  80
  81 #endif  /* __CHECKER__ */
  82
  83 #ifdef CONFIG_GENERIC_BUG
  84 #include <asm-generic/bug.h>
  85
  86 static inline int is_warning_bug(const struct bug_entry *bug)
  87 {
  88         return bug->flags & BUGFLAG_WARNING;
  89 }
  90
  91 const struct bug_entry *find_bug(unsigned long bugaddr);
  92
  93 enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
  94
  95 /* These are defined by the architecture */
  96 int is_valid_bugaddr(unsigned long addr);
  97
  98 #else   /* !CONFIG_GENERIC_BUG */
  99
 100 static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 101                                             struct pt_regs *regs)
 102 {
 103         return BUG_TRAP_TYPE_BUG;
 104 }
 105
 106 #endif  /* CONFIG_GENERIC_BUG */
 107 #endif  /* _LINUX_BUG_H */