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 functions that acquire a lock in the body of a function, and do not release it. */ 37 #define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__))) 38 39 /* 40 * Documents functions that expect a lock to be held on entry to the function, 41 * and release it in the body of the function. 42 */ 43 #define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__))) 44 45 /* Documents functions that try to acquire a lock, and return success or failure. */ 46 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) \ 47 __attribute__((exclusive_trylock_function(__VA_ARGS__))) 48 49 /* Documents a function that expects a mutex to be held prior to entry. */ 50 #define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__))) 51 52 /* Turns off thread safety checking within the body of a particular function. */ 53 #define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis)) 54 55 #else 56 57 #define GUARDED_BY(x) 58 #define PT_GUARDED_BY(x) 59 #define LOCKABLE 60 #define EXCLUSIVE_LOCK_FUNCTION(...) 61 #define UNLOCK_FUNCTION(...) 62 #define EXCLUSIVE_TRYLOCK_FUNCTION(...) 63 #define EXCLUSIVE_LOCKS_REQUIRED(...) 64 #define NO_THREAD_SAFETY_ANALYSIS 65 66 #endif 67 68 /* 69 * A wrapper around the mutex implementation that allows perf to error check 70 * usage, etc. 71 */ 72 struct LOCKABLE mutex { 73 pthread_mutex_t lock; 74 }; 75 76 /* A wrapper around the condition variable implementation. */ 77 struct cond { 78 pthread_cond_t cond; 79 }; 80 81 /* Default initialize the mtx struct. */ 82 void mutex_init(struct mutex *mtx); 83 /* 84 * Initialize the mtx struct and set the process-shared rather than default 85 * process-private attribute. 86 */ 87 void mutex_init_pshared(struct mutex *mtx); 88 void mutex_destroy(struct mutex *mtx); 89 90 void mutex_lock(struct mutex *mtx) EXCLUSIVE_LOCK_FUNCTION(*mtx); 91 void mutex_unlock(struct mutex *mtx) UNLOCK_FUNCTION(*mtx); 92 /* Tries to acquire the lock and returns true on success. */ 93 bool mutex_trylock(struct mutex *mtx) EXCLUSIVE_TRYLOCK_FUNCTION(true, *mtx); 94 95 /* Default initialize the cond struct. */ 96 void cond_init(struct cond *cnd); 97 /* 98 * Initialize the cond struct and specify the process-shared rather than default 99 * process-private attribute. 100 */ 101 void cond_init_pshared(struct cond *cnd); 102 void cond_destroy(struct cond *cnd); 103 104 void cond_wait(struct cond *cnd, struct mutex *mtx) EXCLUSIVE_LOCKS_REQUIRED(mtx); 105 void cond_signal(struct cond *cnd); 106 void cond_broadcast(struct cond *cnd); 107 108 #endif /* __PERF_MUTEX_H */ 109