LXR linux/include/linux/bug.h

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