kernel/msg_q.c - third_party/github/zephyrproject-rtos/zephyr - Git at Google

 /*
  * Copyright (c) 2016 Wind River Systems, Inc.
  *
  * SPDX-License-Identifier: Apache-2.0
  */

 /**
  * @file
  * @brief Message queues.
  */


 #include <zephyr/kernel.h>
 #include <zephyr/kernel_structs.h>

 #include <zephyr/toolchain.h>
 #include <zephyr/linker/sections.h>
 #include <string.h>
 #include <ksched.h>
 #include <zephyr/wait_q.h>
 #include <zephyr/sys/dlist.h>
 #include <zephyr/sys/math_extras.h>
 #include <zephyr/init.h>
 #include <zephyr/syscall_handler.h>
 #include <kernel_internal.h>
 #include <zephyr/sys/check.h>

 #ifdef CONFIG_POLL
 static inline void handle_poll_events(struct k_msgq *msgq, uint32_t state)
 {
 	z_handle_obj_poll_events(&msgq->poll_events, state);
 }
 #endif /* CONFIG_POLL */

 void k_msgq_init(struct k_msgq *msgq, char *buffer, size_t msg_size,
 		 uint32_t max_msgs)
 {
 	msgq->msg_size = msg_size;
 	msgq->max_msgs = max_msgs;
 	msgq->buffer_start = buffer;
 	msgq->buffer_end = buffer + (max_msgs * msg_size);
 	msgq->read_ptr = buffer;
 	msgq->write_ptr = buffer;
 	msgq->used_msgs = 0;
 	msgq->flags = 0;
 	z_waitq_init(&msgq->wait_q);
 	msgq->lock = (struct k_spinlock) {};
 #ifdef CONFIG_POLL
 	sys_dlist_init(&msgq->poll_events);
 #endif	/* CONFIG_POLL */

 	SYS_PORT_TRACING_OBJ_INIT(k_msgq, msgq);

 	z_object_init(msgq);
 }

 int z_impl_k_msgq_alloc_init(struct k_msgq *msgq, size_t msg_size,
 			    uint32_t max_msgs)
 {
 	void *buffer;
 	int ret;
 	size_t total_size;

 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, alloc_init, msgq);

 	if (size_mul_overflow(msg_size, max_msgs, &total_size)) {
 		ret = -EINVAL;
 	} else {
 		buffer = z_thread_malloc(total_size);
 		if (buffer != NULL) {
 			k_msgq_init(msgq, buffer, msg_size, max_msgs);
 			msgq->flags = K_MSGQ_FLAG_ALLOC;
 			ret = 0;
 		} else {
 			ret = -ENOMEM;
 		}
 	}

 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, alloc_init, msgq, ret);

 	return ret;
 }

 #ifdef CONFIG_USERSPACE
 int z_vrfy_k_msgq_alloc_init(struct k_msgq *msgq, size_t msg_size,
 			    uint32_t max_msgs)
 {
 	Z_OOPS(Z_SYSCALL_OBJ_NEVER_INIT(msgq, K_OBJ_MSGQ));

 	return z_impl_k_msgq_alloc_init(msgq, msg_size, max_msgs);
 }
 #include <syscalls/k_msgq_alloc_init_mrsh.c>
 #endif

 int k_msgq_cleanup(struct k_msgq *msgq)
 {
 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, cleanup, msgq);

 	CHECKIF(z_waitq_head(&msgq->wait_q) != NULL) {
 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, cleanup, msgq, -EBUSY);

 		return -EBUSY;
 	}

 	if ((msgq->flags & K_MSGQ_FLAG_ALLOC) != 0U) {
 		k_free(msgq->buffer_start);
 		msgq->flags &= ~K_MSGQ_FLAG_ALLOC;
 	}

 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, cleanup, msgq, 0);

 	return 0;
 }


 int z_impl_k_msgq_put(struct k_msgq *msgq, const void *data, k_timeout_t timeout)
 {
 	__ASSERT(!arch_is_in_isr() || K_TIMEOUT_EQ(timeout, K_NO_WAIT), "");

 	struct k_thread *pending_thread;
 	k_spinlock_key_t key;
 	int result;

 	key = k_spin_lock(&msgq->lock);

 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, put, msgq, timeout);

 	if (msgq->used_msgs < msgq->max_msgs) {
 		/* message queue isn't full */
 		pending_thread = z_unpend_first_thread(&msgq->wait_q);
 		if (pending_thread != NULL) {
 			SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, 0);

 			/* give message to waiting thread */
 			(void)memcpy(pending_thread->base.swap_data, data,
 			       msgq->msg_size);
 			/* wake up waiting thread */
 			arch_thread_return_value_set(pending_thread, 0);
 			z_ready_thread(pending_thread);
 			z_reschedule(&msgq->lock, key);
 			return 0;
 		} else {
 			/* put message in queue */
 			(void)memcpy(msgq->write_ptr, data, msgq->msg_size);
 			msgq->write_ptr += msgq->msg_size;
 			if (msgq->write_ptr == msgq->buffer_end) {
 				msgq->write_ptr = msgq->buffer_start;
 			}
 			msgq->used_msgs++;
 #ifdef CONFIG_POLL
 			handle_poll_events(msgq, K_POLL_STATE_MSGQ_DATA_AVAILABLE);
 #endif /* CONFIG_POLL */
 		}
 		result = 0;
 	} else if (K_TIMEOUT_EQ(timeout, K_NO_WAIT)) {
 		/* don't wait for message space to become available */
 		result = -ENOMSG;
 	} else {
 		SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, put, msgq, timeout);

 		/* wait for put message success, failure, or timeout */
 		_current->base.swap_data = (void *) data;

 		result = z_pend_curr(&msgq->lock, key, &msgq->wait_q, timeout);
 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, result);
 		return result;
 	}

 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, result);

 	k_spin_unlock(&msgq->lock, key);

 	return result;
 }

 #ifdef CONFIG_USERSPACE
 static inline int z_vrfy_k_msgq_put(struct k_msgq *msgq, const void *data,
 				    k_timeout_t timeout)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	Z_OOPS(Z_SYSCALL_MEMORY_READ(data, msgq->msg_size));

 	return z_impl_k_msgq_put(msgq, data, timeout);
 }
 #include <syscalls/k_msgq_put_mrsh.c>
 #endif

 void z_impl_k_msgq_get_attrs(struct k_msgq *msgq, struct k_msgq_attrs *attrs)
 {
 	attrs->msg_size = msgq->msg_size;
 	attrs->max_msgs = msgq->max_msgs;
 	attrs->used_msgs = msgq->used_msgs;
 }

 #ifdef CONFIG_USERSPACE
 static inline void z_vrfy_k_msgq_get_attrs(struct k_msgq *msgq,
 					   struct k_msgq_attrs *attrs)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(attrs, sizeof(struct k_msgq_attrs)));
 	z_impl_k_msgq_get_attrs(msgq, attrs);
 }
 #include <syscalls/k_msgq_get_attrs_mrsh.c>
 #endif

 int z_impl_k_msgq_get(struct k_msgq *msgq, void *data, k_timeout_t timeout)
 {
 	__ASSERT(!arch_is_in_isr() || K_TIMEOUT_EQ(timeout, K_NO_WAIT), "");

 	k_spinlock_key_t key;
 	struct k_thread *pending_thread;
 	int result;

 	key = k_spin_lock(&msgq->lock);

 	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, get, msgq, timeout);

 	if (msgq->used_msgs > 0U) {
 		/* take first available message from queue */
 		(void)memcpy(data, msgq->read_ptr, msgq->msg_size);
 		msgq->read_ptr += msgq->msg_size;
 		if (msgq->read_ptr == msgq->buffer_end) {
 			msgq->read_ptr = msgq->buffer_start;
 		}
 		msgq->used_msgs--;

 		/* handle first thread waiting to write (if any) */
 		pending_thread = z_unpend_first_thread(&msgq->wait_q);
 		if (pending_thread != NULL) {
 			SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, get, msgq, timeout);

 			/* add thread's message to queue */
 			(void)memcpy(msgq->write_ptr, pending_thread->base.swap_data,
 			       msgq->msg_size);
 			msgq->write_ptr += msgq->msg_size;
 			if (msgq->write_ptr == msgq->buffer_end) {
 				msgq->write_ptr = msgq->buffer_start;
 			}
 			msgq->used_msgs++;

 			/* wake up waiting thread */
 			arch_thread_return_value_set(pending_thread, 0);
 			z_ready_thread(pending_thread);
 			z_reschedule(&msgq->lock, key);

 			SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, get, msgq, timeout, 0);

 			return 0;
 		}
 		result = 0;
 	} else if (K_TIMEOUT_EQ(timeout, K_NO_WAIT)) {
 		/* don't wait for a message to become available */
 		result = -ENOMSG;
 	} else {
 		SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, get, msgq, timeout);

 		/* wait for get message success or timeout */
 		_current->base.swap_data = data;

 		result = z_pend_curr(&msgq->lock, key, &msgq->wait_q, timeout);
 		SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, get, msgq, timeout, result);
 		return result;
 	}

 	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, get, msgq, timeout, result);

 	k_spin_unlock(&msgq->lock, key);

 	return result;
 }

 #ifdef CONFIG_USERSPACE
 static inline int z_vrfy_k_msgq_get(struct k_msgq *msgq, void *data,
 				    k_timeout_t timeout)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(data, msgq->msg_size));

 	return z_impl_k_msgq_get(msgq, data, timeout);
 }
 #include <syscalls/k_msgq_get_mrsh.c>
 #endif

 int z_impl_k_msgq_peek(struct k_msgq *msgq, void *data)
 {
 	k_spinlock_key_t key;
 	int result;

 	key = k_spin_lock(&msgq->lock);

 	if (msgq->used_msgs > 0U) {
 		/* take first available message from queue */
 		(void)memcpy(data, msgq->read_ptr, msgq->msg_size);
 		result = 0;
 	} else {
 		/* don't wait for a message to become available */
 		result = -ENOMSG;
 	}

 	SYS_PORT_TRACING_OBJ_FUNC(k_msgq, peek, msgq, result);

 	k_spin_unlock(&msgq->lock, key);

 	return result;
 }

 #ifdef CONFIG_USERSPACE
 static inline int z_vrfy_k_msgq_peek(struct k_msgq *msgq, void *data)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(data, msgq->msg_size));

 	return z_impl_k_msgq_peek(msgq, data);
 }
 #include <syscalls/k_msgq_peek_mrsh.c>
 #endif

 void z_impl_k_msgq_purge(struct k_msgq *msgq)
 {
 	k_spinlock_key_t key;
 	struct k_thread *pending_thread;

 	key = k_spin_lock(&msgq->lock);

 	SYS_PORT_TRACING_OBJ_FUNC(k_msgq, purge, msgq);

 	/* wake up any threads that are waiting to write */
 	while ((pending_thread = z_unpend_first_thread(&msgq->wait_q)) != NULL) {
 		arch_thread_return_value_set(pending_thread, -ENOMSG);
 		z_ready_thread(pending_thread);
 	}

 	msgq->used_msgs = 0;
 	msgq->read_ptr = msgq->write_ptr;

 	z_reschedule(&msgq->lock, key);
 }

 #ifdef CONFIG_USERSPACE
 static inline void z_vrfy_k_msgq_purge(struct k_msgq *msgq)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	z_impl_k_msgq_purge(msgq);
 }
 #include <syscalls/k_msgq_purge_mrsh.c>

 static inline uint32_t z_vrfy_k_msgq_num_free_get(struct k_msgq *msgq)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	return z_impl_k_msgq_num_free_get(msgq);
 }
 #include <syscalls/k_msgq_num_free_get_mrsh.c>

 static inline uint32_t z_vrfy_k_msgq_num_used_get(struct k_msgq *msgq)
 {
 	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
 	return z_impl_k_msgq_num_used_get(msgq);
 }
 #include <syscalls/k_msgq_num_used_get_mrsh.c>

 #endif
	/*
	* Copyright (c) 2016 Wind River Systems, Inc.
	*
	* SPDX-License-Identifier: Apache-2.0
	*/

	/**
	* @file
	* @brief Message queues.
	*/


	#include <zephyr/kernel.h>
	#include <zephyr/kernel_structs.h>

	#include <zephyr/toolchain.h>
	#include <zephyr/linker/sections.h>
	#include <string.h>
	#include <ksched.h>
	#include <zephyr/wait_q.h>
	#include <zephyr/sys/dlist.h>
	#include <zephyr/sys/math_extras.h>
	#include <zephyr/init.h>
	#include <zephyr/syscall_handler.h>
	#include <kernel_internal.h>
	#include <zephyr/sys/check.h>

	#ifdef CONFIG_POLL
	static inline void handle_poll_events(struct k_msgq *msgq, uint32_t state)
	{
	z_handle_obj_poll_events(&msgq->poll_events, state);
	}
	#endif /* CONFIG_POLL */

	void k_msgq_init(struct k_msgq msgq, char buffer, size_t msg_size,
	uint32_t max_msgs)
	{
	msgq->msg_size = msg_size;
	msgq->max_msgs = max_msgs;
	msgq->buffer_start = buffer;
	msgq->buffer_end = buffer + (max_msgs * msg_size);
	msgq->read_ptr = buffer;
	msgq->write_ptr = buffer;
	msgq->used_msgs = 0;
	msgq->flags = 0;
	z_waitq_init(&msgq->wait_q);
	msgq->lock = (struct k_spinlock) {};
	#ifdef CONFIG_POLL
	sys_dlist_init(&msgq->poll_events);
	#endif /* CONFIG_POLL */

	SYS_PORT_TRACING_OBJ_INIT(k_msgq, msgq);

	z_object_init(msgq);
	}

	int z_impl_k_msgq_alloc_init(struct k_msgq *msgq, size_t msg_size,
	uint32_t max_msgs)
	{
	void *buffer;
	int ret;
	size_t total_size;

	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, alloc_init, msgq);

	if (size_mul_overflow(msg_size, max_msgs, &total_size)) {
	ret = -EINVAL;
	} else {
	buffer = z_thread_malloc(total_size);
	if (buffer != NULL) {
	k_msgq_init(msgq, buffer, msg_size, max_msgs);
	msgq->flags = K_MSGQ_FLAG_ALLOC;
	ret = 0;
	} else {
	ret = -ENOMEM;
	}
	}

	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, alloc_init, msgq, ret);

	return ret;
	}

	#ifdef CONFIG_USERSPACE
	int z_vrfy_k_msgq_alloc_init(struct k_msgq *msgq, size_t msg_size,
	uint32_t max_msgs)
	{
	Z_OOPS(Z_SYSCALL_OBJ_NEVER_INIT(msgq, K_OBJ_MSGQ));

	return z_impl_k_msgq_alloc_init(msgq, msg_size, max_msgs);
	}
	#include <syscalls/k_msgq_alloc_init_mrsh.c>
	#endif

	int k_msgq_cleanup(struct k_msgq *msgq)
	{
	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, cleanup, msgq);

	CHECKIF(z_waitq_head(&msgq->wait_q) != NULL) {
	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, cleanup, msgq, -EBUSY);

	return -EBUSY;
	}

	if ((msgq->flags & K_MSGQ_FLAG_ALLOC) != 0U) {
	k_free(msgq->buffer_start);
	msgq->flags &= ~K_MSGQ_FLAG_ALLOC;
	}

	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, cleanup, msgq, 0);

	return 0;
	}


	int z_impl_k_msgq_put(struct k_msgq msgq, const void data, k_timeout_t timeout)
	{
	__ASSERT(!arch_is_in_isr() \|\| K_TIMEOUT_EQ(timeout, K_NO_WAIT), "");

	struct k_thread *pending_thread;
	k_spinlock_key_t key;
	int result;

	key = k_spin_lock(&msgq->lock);

	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, put, msgq, timeout);

	if (msgq->used_msgs < msgq->max_msgs) {
	/* message queue isn't full */
	pending_thread = z_unpend_first_thread(&msgq->wait_q);
	if (pending_thread != NULL) {
	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, 0);

	/* give message to waiting thread */
	(void)memcpy(pending_thread->base.swap_data, data,
	msgq->msg_size);
	/* wake up waiting thread */
	arch_thread_return_value_set(pending_thread, 0);
	z_ready_thread(pending_thread);
	z_reschedule(&msgq->lock, key);
	return 0;
	} else {
	/* put message in queue */
	(void)memcpy(msgq->write_ptr, data, msgq->msg_size);
	msgq->write_ptr += msgq->msg_size;
	if (msgq->write_ptr == msgq->buffer_end) {
	msgq->write_ptr = msgq->buffer_start;
	}
	msgq->used_msgs++;
	#ifdef CONFIG_POLL
	handle_poll_events(msgq, K_POLL_STATE_MSGQ_DATA_AVAILABLE);
	#endif /* CONFIG_POLL */
	}
	result = 0;
	} else if (K_TIMEOUT_EQ(timeout, K_NO_WAIT)) {
	/* don't wait for message space to become available */
	result = -ENOMSG;
	} else {
	SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, put, msgq, timeout);

	/* wait for put message success, failure, or timeout */
	_current->base.swap_data = (void *) data;

	result = z_pend_curr(&msgq->lock, key, &msgq->wait_q, timeout);
	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, result);
	return result;
	}

	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, put, msgq, timeout, result);

	k_spin_unlock(&msgq->lock, key);

	return result;
	}

	#ifdef CONFIG_USERSPACE
	static inline int z_vrfy_k_msgq_put(struct k_msgq msgq, const void data,
	k_timeout_t timeout)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	Z_OOPS(Z_SYSCALL_MEMORY_READ(data, msgq->msg_size));

	return z_impl_k_msgq_put(msgq, data, timeout);
	}
	#include <syscalls/k_msgq_put_mrsh.c>
	#endif

	void z_impl_k_msgq_get_attrs(struct k_msgq msgq, struct k_msgq_attrs attrs)
	{
	attrs->msg_size = msgq->msg_size;
	attrs->max_msgs = msgq->max_msgs;
	attrs->used_msgs = msgq->used_msgs;
	}

	#ifdef CONFIG_USERSPACE
	static inline void z_vrfy_k_msgq_get_attrs(struct k_msgq *msgq,
	struct k_msgq_attrs *attrs)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(attrs, sizeof(struct k_msgq_attrs)));
	z_impl_k_msgq_get_attrs(msgq, attrs);
	}
	#include <syscalls/k_msgq_get_attrs_mrsh.c>
	#endif

	int z_impl_k_msgq_get(struct k_msgq msgq, void data, k_timeout_t timeout)
	{
	__ASSERT(!arch_is_in_isr() \|\| K_TIMEOUT_EQ(timeout, K_NO_WAIT), "");

	k_spinlock_key_t key;
	struct k_thread *pending_thread;
	int result;

	key = k_spin_lock(&msgq->lock);

	SYS_PORT_TRACING_OBJ_FUNC_ENTER(k_msgq, get, msgq, timeout);

	if (msgq->used_msgs > 0U) {
	/* take first available message from queue */
	(void)memcpy(data, msgq->read_ptr, msgq->msg_size);
	msgq->read_ptr += msgq->msg_size;
	if (msgq->read_ptr == msgq->buffer_end) {
	msgq->read_ptr = msgq->buffer_start;
	}
	msgq->used_msgs--;

	/* handle first thread waiting to write (if any) */
	pending_thread = z_unpend_first_thread(&msgq->wait_q);
	if (pending_thread != NULL) {
	SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, get, msgq, timeout);

	/* add thread's message to queue */
	(void)memcpy(msgq->write_ptr, pending_thread->base.swap_data,
	msgq->msg_size);
	msgq->write_ptr += msgq->msg_size;
	if (msgq->write_ptr == msgq->buffer_end) {
	msgq->write_ptr = msgq->buffer_start;
	}
	msgq->used_msgs++;

	/* wake up waiting thread */
	arch_thread_return_value_set(pending_thread, 0);
	z_ready_thread(pending_thread);
	z_reschedule(&msgq->lock, key);

	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, get, msgq, timeout, 0);

	return 0;
	}
	result = 0;
	} else if (K_TIMEOUT_EQ(timeout, K_NO_WAIT)) {
	/* don't wait for a message to become available */
	result = -ENOMSG;
	} else {
	SYS_PORT_TRACING_OBJ_FUNC_BLOCKING(k_msgq, get, msgq, timeout);

	/* wait for get message success or timeout */
	_current->base.swap_data = data;

	result = z_pend_curr(&msgq->lock, key, &msgq->wait_q, timeout);
	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, get, msgq, timeout, result);
	return result;
	}

	SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_msgq, get, msgq, timeout, result);

	k_spin_unlock(&msgq->lock, key);

	return result;
	}

	#ifdef CONFIG_USERSPACE
	static inline int z_vrfy_k_msgq_get(struct k_msgq msgq, void data,
	k_timeout_t timeout)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(data, msgq->msg_size));

	return z_impl_k_msgq_get(msgq, data, timeout);
	}
	#include <syscalls/k_msgq_get_mrsh.c>
	#endif

	int z_impl_k_msgq_peek(struct k_msgq msgq, void data)
	{
	k_spinlock_key_t key;
	int result;

	key = k_spin_lock(&msgq->lock);

	if (msgq->used_msgs > 0U) {
	/* take first available message from queue */
	(void)memcpy(data, msgq->read_ptr, msgq->msg_size);
	result = 0;
	} else {
	/* don't wait for a message to become available */
	result = -ENOMSG;
	}

	SYS_PORT_TRACING_OBJ_FUNC(k_msgq, peek, msgq, result);

	k_spin_unlock(&msgq->lock, key);

	return result;
	}

	#ifdef CONFIG_USERSPACE
	static inline int z_vrfy_k_msgq_peek(struct k_msgq msgq, void data)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	Z_OOPS(Z_SYSCALL_MEMORY_WRITE(data, msgq->msg_size));

	return z_impl_k_msgq_peek(msgq, data);
	}
	#include <syscalls/k_msgq_peek_mrsh.c>
	#endif

	void z_impl_k_msgq_purge(struct k_msgq *msgq)
	{
	k_spinlock_key_t key;
	struct k_thread *pending_thread;

	key = k_spin_lock(&msgq->lock);

	SYS_PORT_TRACING_OBJ_FUNC(k_msgq, purge, msgq);

	/* wake up any threads that are waiting to write */
	while ((pending_thread = z_unpend_first_thread(&msgq->wait_q)) != NULL) {
	arch_thread_return_value_set(pending_thread, -ENOMSG);
	z_ready_thread(pending_thread);
	}

	msgq->used_msgs = 0;
	msgq->read_ptr = msgq->write_ptr;

	z_reschedule(&msgq->lock, key);
	}

	#ifdef CONFIG_USERSPACE
	static inline void z_vrfy_k_msgq_purge(struct k_msgq *msgq)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	z_impl_k_msgq_purge(msgq);
	}
	#include <syscalls/k_msgq_purge_mrsh.c>

	static inline uint32_t z_vrfy_k_msgq_num_free_get(struct k_msgq *msgq)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	return z_impl_k_msgq_num_free_get(msgq);
	}
	#include <syscalls/k_msgq_num_free_get_mrsh.c>

	static inline uint32_t z_vrfy_k_msgq_num_used_get(struct k_msgq *msgq)
	{
	Z_OOPS(Z_SYSCALL_OBJ(msgq, K_OBJ_MSGQ));
	return z_impl_k_msgq_num_used_get(msgq);
	}
	#include <syscalls/k_msgq_num_used_get_mrsh.c>

	#endif