source: rtems-libbsd/rtemsbsd/rtems/rtems-bsd-muteximpl.c @ 8ed1b18

/**
 * @file
 *
 * @ingroup rtems_bsd_rtems
 *
 * @brief TODO.
 */

/*
 * Copyright (c) 2014, 2015 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.
 */

#include <machine/rtems-bsd-kernel-space.h>
#include <machine/rtems-bsd-muteximpl.h>

#include <rtems/score/schedulerimpl.h>
#include <rtems/score/threaddispatch.h>
#include <rtems/score/threadqimpl.h>

#define INTEND_TO_BLOCK \
    (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_INTEND_TO_BLOCK)

#define BLOCKED \
    (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_BLOCKED)

#define INTERRUPT_SATISFIED \
    (THREAD_WAIT_CLASS_OBJECT | THREAD_WAIT_STATE_INTERRUPT_SATISFIED)

void
rtems_bsd_mutex_lock_more(struct lock_object *lock, rtems_bsd_mutex *m,
    Per_CPU_Control *cpu_self, Thread_Control *owner,
    Thread_Control *executing, ISR_lock_Context *lock_context)
{
        if (owner == executing) {
                BSD_ASSERT(lock->lo_flags & LO_RECURSABLE);
                ++m->nest_level;

                _ISR_lock_Release_and_ISR_enable(&m->lock, lock_context);
        } else {
                bool success;

                _RBTree_Insert(&m->rivals, &executing->RBNode,
                    _Thread_queue_Compare_priority, false);
                ++executing->resource_count;

                _Thread_Dispatch_disable_critical(cpu_self);
                _Giant_Acquire(cpu_self);

                /* Priority inheritance */
                _Scheduler_Change_priority_if_higher(_Scheduler_Get(owner),
                    owner, executing->current_priority, false);

                _Thread_Wait_flags_set(executing, INTEND_TO_BLOCK);

                _ISR_lock_Release_and_ISR_enable(&m->lock, lock_context);

                _Thread_Set_state(executing, STATES_WAITING_FOR_MUTEX);

                success = _Thread_Wait_flags_try_change(executing,
                    INTEND_TO_BLOCK, BLOCKED);
                if (!success) {
                        _Thread_Unblock(executing);
                }

                _Giant_Release(cpu_self);
                _Thread_Dispatch_enable(cpu_self);
        }
}

void
rtems_bsd_mutex_unlock_more(rtems_bsd_mutex *m, Thread_Control *owner,
    int keep_priority, RBTree_Node *first, ISR_lock_Context *lock_context)
{
        if (first != NULL) {
                Thread_Control *new_owner;
                bool success;

                _RBTree_Extract(&m->rivals, first);

                new_owner = THREAD_RBTREE_NODE_TO_THREAD(first);
                m->owner = new_owner;

                success = _Thread_Wait_flags_try_change_critical(new_owner,
                    INTEND_TO_BLOCK, INTERRUPT_SATISFIED);
                if (success) {
                        _ISR_lock_Release_and_ISR_enable(&m->lock,
                            lock_context);
                } else {
                        Per_CPU_Control *cpu_self;

                        cpu_self = _Per_CPU_Get();
                        _Thread_Dispatch_disable_critical(cpu_self);
                        _ISR_lock_Release_and_ISR_enable(&m->lock,
                            lock_context);
                        _Giant_Acquire(cpu_self);

                        _Thread_Unblock(new_owner);

                        _Giant_Release(cpu_self);
                        _Thread_Dispatch_enable(cpu_self);
                }
        } else {
                _ISR_lock_Release_and_ISR_enable(&m->lock, lock_context);
        }

        if (!keep_priority) {
                _Thread_Disable_dispatch();
                _Thread_Change_priority(owner, owner->real_priority, true);
                _Thread_Enable_dispatch();
        }
}