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