109 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __PERF_MUTEX_H3#define __PERF_MUTEX_H4 5#include <pthread.h>6#include <stdbool.h>7 8/*9 * A function-like feature checking macro that is a wrapper around10 * `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a11 * nonzero constant integer if the attribute is supported or 0 if not.12 */13#ifdef __has_attribute14#define HAVE_ATTRIBUTE(x) __has_attribute(x)15#else16#define HAVE_ATTRIBUTE(x) 017#endif18 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 by29 * 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#else56 57#define GUARDED_BY(x)58#define PT_GUARDED_BY(x)59#define LOCKABLE60#define EXCLUSIVE_LOCK_FUNCTION(...)61#define UNLOCK_FUNCTION(...)62#define EXCLUSIVE_TRYLOCK_FUNCTION(...)63#define EXCLUSIVE_LOCKS_REQUIRED(...)64#define NO_THREAD_SAFETY_ANALYSIS65 66#endif67 68/*69 * A wrapper around the mutex implementation that allows perf to error check70 * 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 default85 * 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 default99 * 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