| 1 | #ifndef _LINUX_BUG_H
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| 2 | #define _LINUX_BUG_H
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| 3 |
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| 4 | #include <asm/bug.h>
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| 5 | #include <linux/compiler.h>
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| 6 |
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| 7 | enum bug_trap_type {
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| 8 | BUG_TRAP_TYPE_NONE = 0,
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| 9 | BUG_TRAP_TYPE_WARN = 1,
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| 10 | BUG_TRAP_TYPE_BUG = 2,
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| 11 | };
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| 12 |
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| 13 | struct pt_regs;
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| 14 |
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| 15 | #ifdef __CHECKER__
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| 16 | #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) (0)
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| 17 | #define BUILD_BUG_ON_NOT_POWER_OF_2(n) (0)
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| 18 | #define BUILD_BUG_ON_ZERO(e) (0)
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| 19 | #define BUILD_BUG_ON_NULL(e) ((void*)0)
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| 20 | #define BUILD_BUG_ON_INVALID(e) (0)
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| 21 | #define BUILD_BUG_ON_MSG(cond, msg) (0)
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| 22 | #define BUILD_BUG_ON(condition) (0)
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| 23 | #define BUILD_BUG() (0)
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| 24 | #define MAYBE_BUILD_BUG_ON(cond) (0)
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| 25 | #else
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| 26 |
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| 27 |
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| 28 | #define __BUILD_BUG_ON_NOT_POWER_OF_2(n) \
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| 29 | BUILD_BUG_ON(((n) & ((n) - 1)) != 0)
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| 30 | #define BUILD_BUG_ON_NOT_POWER_OF_2(n) \
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| 31 | BUILD_BUG_ON((n) == 0 || (((n) & ((n) - 1)) != 0))
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| 32 |
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| 33 | |
| 34 | result (of value 0 and type size_t), so the expression can be used
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| 35 | e.g. in a structure initializer (or where-ever else comma expressions
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| 36 | aren't permitted).
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| 37 | #define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))
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| 38 | #define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
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| 39 |
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| 40 | |
| 41 | * BUILD_BUG_ON_INVALID() permits the compiler to check the validity of the
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| 42 | * expression but avoids the generation of any code, even if that expression
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| 43 | * has side-effects.
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| 44 |
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| 45 | #define BUILD_BUG_ON_INVALID(e) ((void)(sizeof((__force long)(e))))
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| 46 |
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| 47 | |
| 48 | * BUILD_BUG_ON_MSG - break compile if a condition is true & emit supplied
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| 49 | * error message.
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| 50 | * @condition: the condition which the compiler should know is false.
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| 51 | *
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| 52 | * See BUILD_BUG_ON for description.
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| 53 |
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| 54 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
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| 55 |
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| 56 | |
| 57 | * BUILD_BUG_ON - break compile if a condition is true.
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| 58 | * @condition: the condition which the compiler should know is false.
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| 59 | *
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| 60 | * If you have some code which relies on certain constants being equal, or
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| 61 | * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to
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| 62 | * detect if someone changes it.
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| 63 | *
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| 64 | * The implementation uses gcc's reluctance to create a negative array, but gcc
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| 65 | * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to
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| 66 | * inline functions). Luckily, in 4.3 they added the "error" function
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| 67 | * attribute just for this type of case. Thus, we use a negative sized array
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| 68 | * (should always create an error on gcc versions older than 4.4) and then call
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| 69 | * an undefined function with the error attribute (should always create an
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| 70 | * error on gcc 4.3 and later). If for some reason, neither creates a
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| 71 | * compile-time error, we'll still have a link-time error, which is harder to
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| 72 | * track down.
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| 73 |
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| 74 | #ifndef __OPTIMIZE__
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| 75 | #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
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| 76 | #else
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| 77 | #define BUILD_BUG_ON(condition) \
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| 78 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
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| 79 | #endif
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| 80 |
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| 81 | |
| 82 | * BUILD_BUG - break compile if used.
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| 83 | *
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| 84 | * If you have some code that you expect the compiler to eliminate at
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| 85 | * build time, you should use BUILD_BUG to detect if it is
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| 86 | * unexpectedly used.
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| 87 |
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| 88 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
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| 89 |
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| 90 | #define MAYBE_BUILD_BUG_ON(cond) \
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| 91 | do { \
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| 92 | if (__builtin_constant_p((cond))) \
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| 93 | BUILD_BUG_ON(cond); \
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| 94 | else \
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| 95 | BUG_ON(cond); \
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| 96 | } while (0)
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| 97 |
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| 98 | #endif
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| 99 |
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| 100 | #ifdef CONFIG_GENERIC_BUG
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| 101 | #include <asm-generic/bug.h>
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| 102 |
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| 103 | static inline int is_warning_bug(const struct bug_entry *bug)
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| 104 | {
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| 105 | return bug->flags & BUGFLAG_WARNING;
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| 106 | }
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| 107 |
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| 108 | struct bug_entry *find_bug(unsigned long bugaddr);
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| 109 |
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| 110 | enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs);
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| 111 |
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| 112 |
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| 113 | int is_valid_bugaddr(unsigned long addr);
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| 114 |
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| 115 | #else
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| 116 |
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| 117 | static inline enum bug_trap_type report_bug(unsigned long bug_addr,
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| 118 | struct pt_regs *regs)
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| 119 | {
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| 120 | return BUG_TRAP_TYPE_BUG;
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| 121 | }
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| 122 |
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| 123 | #endif
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| 124 |
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| 125 | |
| 126 | * Since detected data corruption should stop operation on the affected
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| 127 | * structures. Return value must be checked and sanely acted on by caller.
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| 128 |
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| 129 | static inline __must_check bool check_data_corruption(bool v) { return v; }
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| 130 | #define CHECK_DATA_CORRUPTION(condition, fmt, ...) \
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| 131 | check_data_corruption(({ \
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| 132 | bool corruption = unlikely(condition); \
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| 133 | if (corruption) { \
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| 134 | if (IS_ENABLED(CONFIG_BUG_ON_DATA_CORRUPTION)) { \
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| 135 | pr_err(fmt, ##__VA_ARGS__); \
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| 136 | BUG(); \
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| 137 | } else \
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| 138 | WARN(1, fmt, ##__VA_ARGS__); \
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| 139 | } \
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| 140 | corruption; \
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| 141 | }))
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| 142 |
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| 143 | #endif
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