source: rtems-libbsd/rtemsbsd/include/machine/rtems-bsd-muteximpl.h @ 3c967ca

/**
 * @file
 *
 * @ingroup rtems_bsd_machine
 *
 * @brief Implementation of a mutex with a simple priority inheritance
 * protocol.
 */

/*
 * Copyright (c) 2014, 2017 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Dornierstr. 4
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _RTEMS_BSD_MACHINE_RTEMS_BSD_MUTEXIMPL_H_
#define _RTEMS_BSD_MACHINE_RTEMS_BSD_MUTEXIMPL_H_

#include <machine/rtems-bsd-mutex.h>
#include <machine/rtems-bsd-support.h>

#include <sys/types.h>
#include <sys/lock.h>

#include <rtems/score/threadimpl.h>
#include <rtems/score/threadqimpl.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

#define RTEMS_BSD_MUTEX_TQ_OPERATIONS \
    &_Thread_queue_Operations_priority_inherit

static inline void
rtems_bsd_mutex_init(struct lock_object *lock, rtems_bsd_mutex *m,
    struct lock_class *class, const char *name, const char *type, int flags)
{
        _Thread_queue_Initialize(&m->queue, name);
        m->nest_level = 0;

        lock_init(lock, class, name, type, flags);
}

void rtems_bsd_mutex_lock_more(struct lock_object *lock, rtems_bsd_mutex *m,
    Thread_Control *owner, Thread_Control *executing,
    Thread_queue_Context *queue_context);

#define rtems_bsd_mutex_isr_disable(isr_level, queue_context)   \
do {                                                            \
        _ISR_Local_disable(isr_level);                          \
        _ISR_lock_ISR_disable_profile(                          \
              &(queue_context)->Lock_context.Lock_context)      \
} while (0)

static inline void
rtems_bsd_mutex_acquire_critical(rtems_bsd_mutex *m,
    Thread_queue_Context *queue_context)
{

        _Thread_queue_Queue_acquire_critical(&m->queue.Queue,
            &m->queue.Lock_stats, &queue_context->Lock_context.Lock_context);
#if defined(RTEMS_SMP) && defined(RTEMS_DEBUG)
        m->queue.owner = _SMP_lock_Who_am_I();
#endif
}

static inline void
rtems_bsd_mutex_release(rtems_bsd_mutex *m, ISR_Level isr_level,
    Thread_queue_Context *queue_context)
{

#if defined(RTEMS_SMP) && defined(RTEMS_DEBUG)
        _Assert( _Thread_queue_Is_lock_owner( &m->queue ) );
        m->queue.owner = SMP_LOCK_NO_OWNER;
#endif
        _Thread_queue_Queue_release_critical(&m->queue.Queue,
            &queue_context->Lock_context.Lock_context);
        _ISR_Local_enable(isr_level);
}

static inline void
rtems_bsd_mutex_set_isr_level(Thread_queue_Context *queue_context,
    ISR_Level isr_level)
{

        _ISR_lock_Context_set_level(&queue_context->Lock_context.Lock_context,
            isr_level);
}

static inline void
rtems_bsd_mutex_lock(struct lock_object *lock, rtems_bsd_mutex *m)
{
        ISR_Level isr_level;
        Thread_queue_Context queue_context;
        Thread_Control *executing;
        Thread_Control *owner;

        _Thread_queue_Context_initialize(&queue_context);
        rtems_bsd_mutex_isr_disable(isr_level, &queue_context);
        executing = _Thread_Executing;
        rtems_bsd_mutex_acquire_critical(m, &queue_context);

        owner = m->queue.Queue.owner;

        if (__predict_true(owner == NULL)) {
                m->queue.Queue.owner = executing;
                _Thread_Resource_count_increment(executing);
                rtems_bsd_mutex_release(m, isr_level, &queue_context);
        } else {
                rtems_bsd_mutex_set_isr_level(&queue_context, isr_level);
                rtems_bsd_mutex_lock_more(lock, m, owner, executing,
                    &queue_context);
        }
}

static inline int
rtems_bsd_mutex_trylock(struct lock_object *lock, rtems_bsd_mutex *m)
{
        int success;
        ISR_Level isr_level;
        Thread_queue_Context queue_context;
        Thread_Control *executing;
        Thread_Control *owner;

        _Thread_queue_Context_initialize(&queue_context);
        rtems_bsd_mutex_isr_disable(isr_level, &queue_context);
        executing = _Thread_Executing;
        rtems_bsd_mutex_acquire_critical(m, &queue_context);

        owner = m->queue.Queue.owner;

        if (owner == NULL) {
                m->queue.Queue.owner = executing;
                _Thread_Resource_count_increment(executing);
                success = 1;
        } else if (owner == executing) {
                BSD_ASSERT(lock->lo_flags & LO_RECURSABLE);
                ++m->nest_level;
                success = 1;
        } else {
                success = 0;
        }

        rtems_bsd_mutex_release(m, isr_level, &queue_context);

        return (success);
}

static inline void
rtems_bsd_mutex_unlock(rtems_bsd_mutex *m)
{
        ISR_Level isr_level;
        Thread_queue_Context queue_context;
        Thread_Control *owner;
        int nest_level;

        _Thread_queue_Context_initialize(&queue_context);
        rtems_bsd_mutex_isr_disable(isr_level, &queue_context);
        rtems_bsd_mutex_acquire_critical(m, &queue_context);

        nest_level = m->nest_level;
        owner = m->queue.Queue.owner;

        BSD_ASSERT(owner == _Thread_Executing);

        if (__predict_true(nest_level == 0)) {
                Thread_queue_Heads *heads;

                heads = m->queue.Queue.heads;
                m->queue.Queue.owner = NULL;
                _Thread_Resource_count_decrement(owner);

                if (__predict_true(heads == NULL)) {
                        rtems_bsd_mutex_release(m, isr_level, &queue_context);
                } else {
                        rtems_bsd_mutex_set_isr_level(&queue_context, isr_level);
                        _Thread_queue_Surrender(&m->queue.Queue, heads, owner,
                            &queue_context, RTEMS_BSD_MUTEX_TQ_OPERATIONS);
                }
        } else {
                m->nest_level = nest_level - 1;
                rtems_bsd_mutex_release(m, isr_level, &queue_context);
        }
}

static inline int
rtems_bsd_mutex_owned(rtems_bsd_mutex *m)
{

        return (m->queue.Queue.owner == _Thread_Get_executing());
}

static inline int
rtems_bsd_mutex_recursed(rtems_bsd_mutex *m)
{

        return (m->nest_level);
}

static inline void
rtems_bsd_mutex_destroy(struct lock_object *lock, rtems_bsd_mutex *m)
{
        BSD_ASSERT(m->queue.Queue.heads == NULL);

        if (rtems_bsd_mutex_owned(m)) {
                m->nest_level = 0;
                rtems_bsd_mutex_unlock(m);
        }

        _Thread_queue_Destroy(&m->queue);
        lock_destroy(lock);
}

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif /* _RTEMS_BSD_MACHINE_RTEMS_BSD_MUTEXIMPL_H_ */