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_NOT_POWER_OF_2(n) (0)
  18#define BUILD_BUG_ON_ZERO(e) (0)
  19#define BUILD_BUG_ON_NULL(e) ((void*)0)
  20#define BUILD_BUG_ON_INVALID(e) (0)
  21#define BUILD_BUG_ON_MSG(cond, msg) (0)
  22#define BUILD_BUG_ON(condition) (0)
  23#define BUILD_BUG() (0)
  24#define MAYBE_BUILD_BUG_ON(cond) (0)
  25#else /* __CHECKER__ */
  26
  27/* Force a compilation error if a constant expression is not a power of 2 */
  28#define __BUILD_BUG_ON_NOT_POWER_OF_2(n)        \
  29        BUILD_BUG_ON(((n) & ((n) - 1)) != 0)
  30#define BUILD_BUG_ON_NOT_POWER_OF_2(n)                  \
  31        BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
  32
  33/* Force a compilation error if condition is true, but also produce a
  34   result (of value 0 and type size_t), so the expression can be used
  35   e.g. in a structure initializer (or where-ever else comma expressions
  36   aren't permitted). */
  37#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
  38#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
  39
  40/*
  41 * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
  42 * expression but avoids the generation of any code, even if that expression
  43 * has side-effects.
  44 */
  45#define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
  46
  47/**
  48 * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied
  49 *                    error message.
  50 * @condition: the condition which the compiler should know is false.
  51 *
  52 * See BUILD_BUG_ON for description.
  53 */
  54#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
  55
  56/**
  57 * BUILD_BUG_ON - break compile if a condition is true.
  58 * @condition: the condition which the compiler should know is false.
  59 *
  60 * If you have some code which relies on certain constants being equal, or
  61 * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
  62 * detect if someone changes it.
  63 *
  64 * The implementation uses gcc's reluctance to create a negative array, but gcc
  65 * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to
  66 * inline functions).  Luckily, in 4.3 they added the "error" function
  67 * attribute just for this type of case.  Thus, we use a negative sized array
  68 * (should always create an error on gcc versions older than 4.4) and then call
  69 * an undefined function with the error attribute (should always create an
  70 * error on gcc 4.3 and later).  If for some reason, neither creates a
  71 * compile-time error, we'll still have a link-time error, which is harder to
  72 * track down.
  73 */
  74#ifndef __OPTIMIZE__
  75#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
  76#else
  77#define BUILD_BUG_ON(condition) \
  78        BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
  79#endif
  80
  81/**
  82 * BUILD_BUG - break compile if used.
  83 *
  84 * If you have some code that you expect the compiler to eliminate at
  85 * build time, you should use BUILD_BUG to detect if it is
  86 * unexpectedly used.
  87 */
  88#define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
  89
  90#define MAYBE_BUILD_BUG_ON(cond)                        \
  91        do {                                            \
  92                if (__builtin_constant_p((cond)))       \
  93                        BUILD_BUG_ON(cond);             \
  94                else                                    \
  95                        BUG_ON(cond);                   \
  96        } while (0)
  97
  98#endif  /* __CHECKER__ */
  99
 100#ifdef CONFIG_GENERIC_BUG
 101#include <asm-generic/bug.h>
 102
 103static inline int is_warning_bug(const struct bug_entry *bug)
 104{
 105        return bug->flags & BUGFLAG_WARNING;
 106}
 107
 108struct bug_entry *find_bug(unsigned long bugaddr);
 109
 110enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
 111
 112/* These are defined by the architecture */
 113int is_valid_bugaddr(unsigned long addr);
 114
 115#else   /* !CONFIG_GENERIC_BUG */
 116
 117static inline enum bug_trap_type report_bug(unsigned long bug_addr,
 118                                            struct pt_regs *regs)
 119{
 120        return BUG_TRAP_TYPE_BUG;
 121}
 122
 123#endif  /* CONFIG_GENERIC_BUG */
 124
 125/*
 126 * Since detected data corruption should stop operation on the affected
 127 * structures. Return value must be checked and sanely acted on by caller.
 128 */
 129static inline __must_check bool check_data_corruption(bool v) { return v; }
 130#define CHECK_DATA_CORRUPTION(condition, fmt, ...)                       \
 131        check_data_corruption(({                                         \
 132                bool corruption = unlikely(condition);                   \
 133                if (corruption) {                                        \
 134                        if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
 135                                pr_err(fmt, ##__VA_ARGS__);              \
 136                                BUG();                                   \
 137                        } else                                           \
 138                                WARN(1, fmt, ##__VA_ARGS__);             \
 139                }                                                        \
 140                corruption;                                              \
 141        }))
 142
 143#endif  /* _LINUX_BUG_H */
 144