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 */ 72struct LOCKABLE mutex { 73 pthread_mutex_t lock; 74}; 75 76/* A wrapper around the condition variable implementation. */ 77struct cond { 78 pthread_cond_t cond; 79}; 80 81/* Default initialize the mtx struct. */ 82void mutex_init(struct mutex *mtx); 83/* 84 * Initialize the mtx struct and set the process-shared rather than default 85 * process-private attribute. 86 */ 87void mutex_init_pshared(struct mutex *mtx); 88void mutex_destroy(struct mutex *mtx); 89 90void mutex_lock(struct mutex *mtx) EXCLUSIVE_LOCK_FUNCTION(*mtx); 91void mutex_unlock(struct mutex *mtx) UNLOCK_FUNCTION(*mtx); 92/* Tries to acquire the lock and returns true on success. */ 93bool mutex_trylock(struct mutex *mtx) EXCLUSIVE_TRYLOCK_FUNCTION(true, *mtx); 94 95/* Default initialize the cond struct. */ 96void cond_init(struct cond *cnd); 97/* 98 * Initialize the cond struct and specify the process-shared rather than default 99 * process-private attribute. 100 */ 101void cond_init_pshared(struct cond *cnd); 102void cond_destroy(struct cond *cnd); 103 104void cond_wait(struct cond *cnd, struct mutex *mtx) EXCLUSIVE_LOCKS_REQUIRED(mtx); 105void cond_signal(struct cond *cnd); 106void cond_broadcast(struct cond *cnd); 107 108#endif /* __PERF_MUTEX_H */ 109