8  * @file @brief mutex kernel services
10  * This module contains routines for handling mutex locking and unlocking.
14  * priority thread waiting on the mutex.
16  * Each mutex that contributes to priority inheritance must be released in the
17  * reverse order in which it was acquired.  Furthermore each subsequent mutex
22  * priority level, the second mutex M2 must be acquired by thread A after
23  * thread A's priority level was bumped due to owning the first mutex M1.
24  * When releasing the mutex, thread A must release M2 before it releases M1.
55 int z_impl_k_mutex_init(struct k_mutex *mutex)  in z_impl_k_mutex_init()  argument
57 	mutex->owner = NULL;  in z_impl_k_mutex_init()
58 	mutex->lock_count = 0U;  in z_impl_k_mutex_init()
60 	z_waitq_init(&mutex->wait_q);  in z_impl_k_mutex_init()
62 	k_object_init(mutex);  in z_impl_k_mutex_init()
65 	k_obj_core_init_and_link(K_OBJ_CORE(mutex), &obj_type_mutex);  in z_impl_k_mutex_init()
68 	SYS_PORT_TRACING_OBJ_INIT(k_mutex, mutex, 0);  in z_impl_k_mutex_init()
74 static inline int z_vrfy_k_mutex_init(struct k_mutex *mutex)  in z_vrfy_k_mutex_init()  argument
76 	K_OOPS(K_SYSCALL_OBJ_INIT(mutex, K_OBJ_MUTEX));  in z_vrfy_k_mutex_init()
77 	return z_impl_k_mutex_init(mutex);  in z_vrfy_k_mutex_init()
91 static bool adjust_owner_prio(struct k_mutex *mutex, int32_t new_prio)  in adjust_owner_prio()  argument
93 	if (mutex->owner->base.prio != new_prio) {  in adjust_owner_prio()
96 			mutex->owner, z_is_thread_ready(mutex->owner) ?  in adjust_owner_prio()
98 			new_prio, mutex->owner->base.prio);  in adjust_owner_prio()
100 		return z_thread_prio_set(mutex->owner, new_prio);  in adjust_owner_prio()
105 int z_impl_k_mutex_lock(struct k_mutex *mutex, k_timeout_t timeout)  in z_impl_k_mutex_lock()  argument
113 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_mutex, lock, mutex, timeout);  in z_impl_k_mutex_lock()
117 	if (likely((mutex->lock_count == 0U) || (mutex->owner == arch_current_thread()))) {  in z_impl_k_mutex_lock()
119 		mutex->owner_orig_prio = (mutex->lock_count == 0U) ?  in z_impl_k_mutex_lock()
121 					mutex->owner_orig_prio;  in z_impl_k_mutex_lock()
123 		mutex->lock_count++;  in z_impl_k_mutex_lock()
124 		mutex->owner = arch_current_thread();  in z_impl_k_mutex_lock()
126 		LOG_DBG("%p took mutex %p, count: %d, orig prio: %d",  in z_impl_k_mutex_lock()
127 			arch_current_thread(), mutex, mutex->lock_count,  in z_impl_k_mutex_lock()
128 			mutex->owner_orig_prio);  in z_impl_k_mutex_lock()
132 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, lock, mutex, timeout, 0);  in z_impl_k_mutex_lock()
140 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, lock, mutex, timeout, -EBUSY);  in z_impl_k_mutex_lock()
145 	SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_mutex, lock, mutex, timeout);  in z_impl_k_mutex_lock()
148 					    mutex->owner->base.prio);  in z_impl_k_mutex_lock()
150 	LOG_DBG("adjusting prio up on mutex %p", mutex);  in z_impl_k_mutex_lock()
152 	if (z_is_prio_higher(new_prio, mutex->owner->base.prio)) {  in z_impl_k_mutex_lock()
153 		resched = adjust_owner_prio(mutex, new_prio);  in z_impl_k_mutex_lock()
156 	int got_mutex = z_pend_curr(&lock, key, &mutex->wait_q, timeout);  in z_impl_k_mutex_lock()
158 	LOG_DBG("on mutex %p got_mutex value: %d", mutex, got_mutex);  in z_impl_k_mutex_lock()
160 	LOG_DBG("%p got mutex %p (y/n): %c", arch_current_thread(), mutex,  in z_impl_k_mutex_lock()
164 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, lock, mutex, timeout, 0);  in z_impl_k_mutex_lock()
170 	LOG_DBG("%p timeout on mutex %p", arch_current_thread(), mutex);  in z_impl_k_mutex_lock()
175 	 * Check if mutex was unlocked after this thread was unpended.  in z_impl_k_mutex_lock()
178 	if (likely(mutex->owner != NULL)) {  in z_impl_k_mutex_lock()
179 		struct k_thread *waiter = z_waitq_head(&mutex->wait_q);  in z_impl_k_mutex_lock()
182 			new_prio_for_inheritance(waiter->base.prio, mutex->owner_orig_prio) :  in z_impl_k_mutex_lock()
183 			mutex->owner_orig_prio;  in z_impl_k_mutex_lock()
185 		LOG_DBG("adjusting prio down on mutex %p", mutex);  in z_impl_k_mutex_lock()
187 		resched = adjust_owner_prio(mutex, new_prio) || resched;  in z_impl_k_mutex_lock()
196 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, lock, mutex, timeout, -EAGAIN);  in z_impl_k_mutex_lock()
202 static inline int z_vrfy_k_mutex_lock(struct k_mutex *mutex,  in z_vrfy_k_mutex_lock()  argument
205 	K_OOPS(K_SYSCALL_OBJ(mutex, K_OBJ_MUTEX));  in z_vrfy_k_mutex_lock()
206 	return z_impl_k_mutex_lock(mutex, timeout);  in z_vrfy_k_mutex_lock()
211 int z_impl_k_mutex_unlock(struct k_mutex *mutex)  in z_impl_k_mutex_unlock()  argument
217 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_mutex, unlock, mutex);  in z_impl_k_mutex_unlock()
219 	CHECKIF(mutex->owner == NULL) {  in z_impl_k_mutex_unlock()
220 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, unlock, mutex, -EINVAL);  in z_impl_k_mutex_unlock()
225 	 * The current thread does not own the mutex.  in z_impl_k_mutex_unlock()
227 	CHECKIF(mutex->owner != arch_current_thread()) {  in z_impl_k_mutex_unlock()
228 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, unlock, mutex, -EPERM);  in z_impl_k_mutex_unlock()
234 	 * Attempt to unlock a mutex which is unlocked. mutex->lock_count  in z_impl_k_mutex_unlock()
235 	 * cannot be zero if the current thread is equal to mutex->owner,  in z_impl_k_mutex_unlock()
239 	__ASSERT_NO_MSG(mutex->lock_count > 0U);  in z_impl_k_mutex_unlock()
241 	LOG_DBG("mutex %p lock_count: %d", mutex, mutex->lock_count);  in z_impl_k_mutex_unlock()
247 	if (mutex->lock_count > 1U) {  in z_impl_k_mutex_unlock()
248 		mutex->lock_count--;  in z_impl_k_mutex_unlock()
254 	adjust_owner_prio(mutex, mutex->owner_orig_prio);  in z_impl_k_mutex_unlock()
257 	new_owner = z_unpend_first_thread(&mutex->wait_q);  in z_impl_k_mutex_unlock()
259 	mutex->owner = new_owner;  in z_impl_k_mutex_unlock()
261 	LOG_DBG("new owner of mutex %p: %p (prio: %d)",  in z_impl_k_mutex_unlock()
262 		mutex, new_owner, new_owner ? new_owner->base.prio : -1000);  in z_impl_k_mutex_unlock()
270 		mutex->owner_orig_prio = new_owner->base.prio;  in z_impl_k_mutex_unlock()
275 		mutex->lock_count = 0U;  in z_impl_k_mutex_unlock()
281 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, unlock, mutex, 0);  in z_impl_k_mutex_unlock()
287 static inline int z_vrfy_k_mutex_unlock(struct k_mutex *mutex)  in z_vrfy_k_mutex_unlock()  argument
289 	K_OOPS(K_SYSCALL_OBJ(mutex, K_OBJ_MUTEX));  in z_vrfy_k_mutex_unlock()
290 	return z_impl_k_mutex_unlock(mutex);  in z_vrfy_k_mutex_unlock()
298 	/* Initialize mutex object type */  in init_mutex_obj_core_list()
305 	STRUCT_SECTION_FOREACH(k_mutex, mutex) {  in init_mutex_obj_core_list()
306 		k_obj_core_init_and_link(K_OBJ_CORE(mutex), &obj_type_mutex);  in init_mutex_obj_core_list()