1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __PERF_MUTEX_H 3 #define __PERF_MUTEX_H 4 5 #include <pthread.h> 6 #include <stdbool.h> 7 8 /* 9 * A function-like feature checking macro that is a wrapper around 10 * `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a 11 * nonzero constant integer if the attribute is supported or 0 if not. 12 */ 13 #ifdef __has_attribute 14 #define HAVE_ATTRIBUTE(x) __has_attribute(x) 15 #else 16 #define HAVE_ATTRIBUTE(x) 0 17 #endif 18 19 #if HAVE_ATTRIBUTE(guarded_by) && HAVE_ATTRIBUTE(pt_guarded_by) && \ 20 HAVE_ATTRIBUTE(lockable) && HAVE_ATTRIBUTE(exclusive_lock_function) && \ 21 HAVE_ATTRIBUTE(exclusive_trylock_function) && HAVE_ATTRIBUTE(exclusive_locks_required) && \ 22 HAVE_ATTRIBUTE(no_thread_safety_analysis) 23 24 /* Documents if a shared field or global variable needs to be protected by a mutex. */ 25 #define GUARDED_BY(x) __attribute__((guarded_by(x))) 26 27 /* 28 * Documents if the memory location pointed to by a pointer should be guarded by 29 * a mutex when dereferencing the pointer. 30 */ 31 #define PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x))) 32 33 /* Documents if a type is a lockable type. */ 34 #define LOCKABLE __attribute__((lockable)) 35 36 /* Documents a function that expects a lock not to be held prior to entry. */ 37 #define LOCKS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__))) 38 39 /* Documents a function that returns a lock. */ 40 #define LOCK_RETURNED(x) __attribute__((lock_returned(x))) 41 42 /* Documents functions that acquire a lock in the body of a function, and do not release it. */ 43 #define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__))) 44 45 /* 46 * Documents functions that acquire a shared (reader) lock in the body of a 47 * function, and do not release it. 48 */ 49 #define SHARED_LOCK_FUNCTION(...) __attribute__((shared_lock_function(__VA_ARGS__))) 50 51 /* 52 * Documents functions that expect a lock to be held on entry to the function, 53 * and release it in the body of the function. 54 */ 55 #define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__))) 56 57 /* Documents functions that try to acquire a lock, and return success or failure. */ 58 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) \ 59 __attribute__((exclusive_trylock_function(__VA_ARGS__))) 60 61 /* Documents a function that expects a mutex to be held prior to entry. */ 62 #define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__))) 63 64 /* Documents a function that expects a shared (reader) lock to be held prior to entry. */ 65 #define SHARED_LOCKS_REQUIRED(...) __attribute__((shared_locks_required(__VA_ARGS__))) 66 67 /* Turns off thread safety checking within the body of a particular function. */ 68 #define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis)) 69 70 #else 71 72 #define GUARDED_BY(x) 73 #define PT_GUARDED_BY(x) 74 #define LOCKABLE 75 #define LOCKS_EXCLUDED(...) 76 #define LOCK_RETURNED(x) 77 #define EXCLUSIVE_LOCK_FUNCTION(...) 78 #define SHARED_LOCK_FUNCTION(...) 79 #define UNLOCK_FUNCTION(...) 80 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) 81 #define EXCLUSIVE_LOCKS_REQUIRED(...) 82 #define SHARED_LOCKS_REQUIRED(...) 83 #define NO_THREAD_SAFETY_ANALYSIS 84 85 #endif 86 87 /* 88 * A wrapper around the mutex implementation that allows perf to error check 89 * usage, etc. 90 */ 91 struct LOCKABLE mutex { 92 pthread_mutex_t lock; 93 }; 94 95 /* A wrapper around the condition variable implementation. */ 96 struct cond { 97 pthread_cond_t cond; 98 }; 99 100 /* Default initialize the mtx struct. */ 101 void mutex_init(struct mutex *mtx); 102 /* 103 * Initialize the mtx struct and set the process-shared rather than default 104 * process-private attribute. 105 */ 106 void mutex_init_pshared(struct mutex *mtx); 107 void mutex_destroy(struct mutex *mtx); 108 109 void mutex_lock(struct mutex *mtx) EXCLUSIVE_LOCK_FUNCTION(*mtx); 110 void mutex_unlock(struct mutex *mtx) UNLOCK_FUNCTION(*mtx); 111 /* Tries to acquire the lock and returns true on success. */ 112 bool mutex_trylock(struct mutex *mtx) EXCLUSIVE_TRYLOCK_FUNCTION(true, *mtx); 113 114 /* Default initialize the cond struct. */ 115 void cond_init(struct cond *cnd); 116 /* 117 * Initialize the cond struct and specify the process-shared rather than default 118 * process-private attribute. 119 */ 120 void cond_init_pshared(struct cond *cnd); 121 void cond_destroy(struct cond *cnd); 122 123 void cond_wait(struct cond *cnd, struct mutex *mtx) EXCLUSIVE_LOCKS_REQUIRED(mtx); 124 void cond_signal(struct cond *cnd); 125 void cond_broadcast(struct cond *cnd); 126 127 #endif /* __PERF_MUTEX_H */ 128