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_ZERO(e) (0)
  18 #define BUILD_BUG_ON_NULL(e) ((void*)0)
  19 #define BUILD_BUG_ON_INVALID(e) (0)
  20 #define BUILD_BUG_ON(condition) (0)
  21 #define BUILD_BUG() (0)
  22 #else /* __CHECKER__ */
  23
  24 /* Force a compilation error if a constant expression is not a power of 2 */
  25 #define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
  26         BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
  27
  28 /* Force a compilation error if condition is true, but also produce a
  29    result (of value 0 and type size_t), so the expression can be used
  30    e.g. in a structure initializer (or where-ever else comma expressions
  31    aren't permitted). */
  32 #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
  33 #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  34
  35 /*
  36  * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
  37  * expression but avoids the generation of any code, even if that expression
  38  * has side-effects.
  39  */
  40 #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
  41
  42 /**
  43  * BUILD_BUG_ON - break compile if a condition is true.
  44  * @condition: the condition which the compiler should know is false.
  45  *
  46  * If you have some code which relies on certain constants being equal, or
  47  * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
  48  * detect if someone changes it.
  49  *
  50  * The implementation uses gcc's reluctance to create a negative array, but gcc
  51  * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to
  52  * inline functions).  Luckily, in 4.3 they added the "error" function
  53  * attribute just for this type of case.  Thus, we use a negative sized array
  54  * (should always create an error on gcc versions older than 4.4) and then call
  55  * an undefined function with the error attribute (should always create an
  56  * error on gcc 4.3 and later).  If for some reason, neither creates a
  57  * compile-time error, we'll still have a link-time error, which is harder to
  58  * track down.
  59  */
  60 #ifndef __OPTIMIZE__
  61 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
  62 #else
  63 #define BUILD_BUG_ON(condition)                                         \
  64         do {                                                            \
  65                 bool __cond = !!(condition);                            \
  66                 extern void __build_bug_on_failed(void)                 \
  67                         __compiletime_error("BUILD_BUG_ON failed");     \
  68                 if (__cond)                                             \
  69                         __build_bug_on_failed();                        \
  70                 __compiletime_error_fallback(__cond);                   \
  71         } while (0)
  72 #endif
  73
  74 /**
  75  * BUILD_BUG - break compile if used.
  76  *
  77  * If you have some code that you expect the compiler to eliminate at
  78  * build time, you should use BUILD_BUG to detect if it is
  79  * unexpectedly used.
  80  */
  81 #define BUILD_BUG()                                             \
  82         do {                                                    \
  83                 extern void __build_bug_failed(void)            \
  84                         __compiletime_error("BUILD_BUG failed");\
  85                 __build_bug_failed();                           \
  86         } while (0)
  87
  88 #endif  /* __CHECKER__ */
  89
  90 #ifdef CONFIG_GENERIC_BUG
  91 #include <asm-generic/bug.h>
  92
  93 static inline int is_warning_bug(const struct bug_entry *bug)
  94 {
  95         return bug->flags & BUGFLAG_WARNING;
  96 }
  97
  98 const struct bug_entry *find_bug(unsigned long bugaddr);
  99
 100 enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
 101
 102 /* These are defined by the architecture */
 103 int is_valid_bugaddr(unsigned long addr);
 104
 105 #else   /* !CONFIG_GENERIC_BUG */
 106
 107 static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 108                                             struct pt_regs *regs)
 109 {
 110         return BUG_TRAP_TYPE_BUG;
 111 }
 112
 113 #endif  /* CONFIG_GENERIC_BUG */
 114 #endif  /* _LINUX_BUG_H */