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_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
 100 static inline int is_warning_bug(const struct bug_entry *bug)
 101 {
 102         return bug->flags & BUGFLAG_WARNING;
 103 }
 104
 105 const struct bug_entry *find_bug(unsigned long bugaddr);
 106
 107 enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
 108
 109 /* These are defined by the architecture */
 110 int is_valid_bugaddr(unsigned long addr);
 111
 112 #else   /* !CONFIG_GENERIC_BUG */
 113
 114 static 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 */