LXR linux/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
   7enum bug_trap_type {
   8        BUG_TRAP_TYPE_NONE = 0,
   9        BUG_TRAP_TYPE_WARN = 1,
  10        BUG_TRAP_TYPE_BUG = 2,
  11};
  12
  13struct 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_MSG(cond, msg) (0)
  21#define BUILD_BUG_ON(condition) (0)
  22#define BUILD_BUG() (0)
  23#define MAYBE_BUILD_BUG_ON(cond) (0)
  24#else /* __CHECKER__ */
  25
  26/* Force a compilation error if a constant expression is not a power of 2 */
  27#define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
  28        BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
  29
  30/* Force a compilation error if condition is true, but also produce a
  31   result (of value 0 and type size_t), so the expression can be used
  32   e.g. in a structure initializer (or where-ever else comma expressions
  33   aren't permitted). */
  34#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
  35#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  36
  37/*
  38 * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
  39 * expression but avoids the generation of any code, even if that expression
  40 * has side-effects.
  41 */
  42#define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
  43
  44/**
  45 * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied
  46 *                    error message.
  47 * @condition: the condition which the compiler should know is false.
  48 *
  49 * See BUILD_BUG_ON for description.
  50 */
  51#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
  52
  53/**
  54 * BUILD_BUG_ON - break compile if a condition is true.
  55 * @condition: the condition which the compiler should know is false.
  56 *
  57 * If you have some code which relies on certain constants being equal, or
  58 * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
  59 * detect if someone changes it.
  60 *
  61 * The implementation uses gcc's reluctance to create a negative array, but gcc
  62 * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to
  63 * inline functions).  Luckily, in 4.3 they added the "error" function
  64 * attribute just for this type of case.  Thus, we use a negative sized array
  65 * (should always create an error on gcc versions older than 4.4) and then call
  66 * an undefined function with the error attribute (should always create an
  67 * error on gcc 4.3 and later).  If for some reason, neither creates a
  68 * compile-time error, we'll still have a link-time error, which is harder to
  69 * track down.
  70 */
  71#ifndef __OPTIMIZE__
  72#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
  73#else
  74#define BUILD_BUG_ON(condition) \
  75        BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
  76#endif
  77
  78/**
  79 * BUILD_BUG - break compile if used.
  80 *
  81 * If you have some code that you expect the compiler to eliminate at
  82 * build time, you should use BUILD_BUG to detect if it is
  83 * unexpectedly used.
  84 */
  85#define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
  86
  87#define MAYBE_BUILD_BUG_ON(cond)                        \
  88        do {                                            \
  89                if (__builtin_constant_p((cond)))       \
  90                        BUILD_BUG_ON(cond);             \
  91                else                                    \
  92                        BUG_ON(cond);                   \
  93        } while (0)
  94
  95#endif  /* __CHECKER__ */
  96
  97#ifdef CONFIG_GENERIC_BUG
  98#include <asm-generic/bug.h>
  99
 100static inline int is_warning_bug(const struct bug_entry *bug)
 101{
 102        return bug->flags & BUGFLAG_WARNING;
 103}
 104
 105const struct bug_entry *find_bug(unsigned long bugaddr);
 106
 107enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
 108
 109/* These are defined by the architecture */
 110int is_valid_bugaddr(unsigned long addr);
 111
 112#else   /* !CONFIG_GENERIC_BUG */
 113
 114static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 115                                            struct pt_regs *regs)
 116{
 117        return BUG_TRAP_TYPE_BUG;
 118}
 119
 120#endif  /* CONFIG_GENERIC_BUG */
 121#endif  /* _LINUX_BUG_H */
 122