388 lines
10 KiB
C
388 lines
10 KiB
C
/****************************************************************************
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* sched/semaphore/spinlock.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <sched.h>
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#include <assert.h>
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#include <nuttx/spinlock.h>
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#include <nuttx/sched_note.h>
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#include <arch/irq.h>
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#include "sched/sched.h"
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#ifdef CONFIG_SPINLOCK
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: spin_lock
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*
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* Description:
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* If this CPU does not already hold the spinlock, then loop until the
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* spinlock is successfully locked.
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*
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* This implementation is non-reentrant and is prone to deadlocks in
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* the case that any logic on the same CPU attempts to take the lock
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* more than once.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to lock.
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*
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* Returned Value:
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* None. When the function returns, the spinlock was successfully locked
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* by this CPU.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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void spin_lock(FAR volatile spinlock_t *lock)
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{
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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/* Notify that we are waiting for a spinlock */
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sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_LOCK);
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#endif
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while (up_testset(lock) == SP_LOCKED)
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{
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SP_DSB();
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SP_WFE();
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}
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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/* Notify that we have the spinlock */
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sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_LOCKED);
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#endif
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SP_DMB();
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}
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/****************************************************************************
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* Name: spin_lock_wo_note
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*
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* Description:
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* If this CPU does not already hold the spinlock, then loop until the
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* spinlock is successfully locked.
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*
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* This implementation is the same as the above spin_lock() except that
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* it does not perform instrumentation logic.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to lock.
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*
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* Returned Value:
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* None. When the function returns, the spinlock was successfully locked
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* by this CPU.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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void spin_lock_wo_note(FAR volatile spinlock_t *lock)
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{
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while (up_testset(lock) == SP_LOCKED)
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{
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SP_DSB();
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SP_WFE();
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}
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SP_DMB();
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}
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/****************************************************************************
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* Name: spin_trylock
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*
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* Description:
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* Try once to lock the spinlock. Do not wait if the spinlock is already
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* locked.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to lock.
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*
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* Returned Value:
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* SP_LOCKED - Failure, the spinlock was already locked
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* SP_UNLOCKED - Success, the spinlock was successfully locked
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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spinlock_t spin_trylock(FAR volatile spinlock_t *lock)
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{
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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/* Notify that we are waiting for a spinlock */
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sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_LOCK);
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#endif
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if (up_testset(lock) == SP_LOCKED)
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{
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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/* Notify that we abort for a spinlock */
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sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_ABORT);
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#endif
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SP_DSB();
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return SP_LOCKED;
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}
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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/* Notify that we have the spinlock */
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sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_LOCKED);
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#endif
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SP_DMB();
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return SP_UNLOCKED;
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}
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/****************************************************************************
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* Name: spin_trylock_wo_note
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*
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* Description:
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* Try once to lock the spinlock. Do not wait if the spinlock is already
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* locked.
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*
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* This implementation is the same as the above spin_trylock() except that
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* it does not perform instrumentation logic.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to lock.
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*
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* Returned Value:
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* SP_LOCKED - Failure, the spinlock was already locked
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* SP_UNLOCKED - Success, the spinlock was successfully locked
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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spinlock_t spin_trylock_wo_note(FAR volatile spinlock_t *lock)
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{
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if (up_testset(lock) == SP_LOCKED)
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{
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SP_DSB();
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return SP_LOCKED;
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}
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SP_DMB();
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return SP_UNLOCKED;
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}
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/****************************************************************************
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* Name: spin_unlock
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*
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* Description:
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* Release one count on a non-reentrant spinlock.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to unlock.
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*
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* Returned Value:
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* None.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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#ifdef __SP_UNLOCK_FUNCTION
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void spin_unlock(FAR volatile spinlock_t *lock)
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{
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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/* Notify that we are unlocking the spinlock */
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sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_UNLOCK);
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#endif
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SP_DMB();
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*lock = SP_UNLOCKED;
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SP_DSB();
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SP_SEV();
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}
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#endif
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/****************************************************************************
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* Name: spin_unlock_wo_note
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*
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* Description:
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* Release one count on a non-reentrant spinlock.
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*
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* This implementation is the same as the above spin_unlock() except that
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* it does not perform instrumentation logic.
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*
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* Input Parameters:
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* lock - A reference to the spinlock object to unlock.
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*
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* Returned Value:
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* None.
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*
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* Assumptions:
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* Not running at the interrupt level.
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*
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****************************************************************************/
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void spin_unlock_wo_note(FAR volatile spinlock_t *lock)
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{
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SP_DMB();
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*lock = SP_UNLOCKED;
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SP_DSB();
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SP_SEV();
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}
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/****************************************************************************
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* Name: spin_setbit
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*
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* Description:
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* Makes setting a CPU bit in a bitset an atomic action
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*
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* Input Parameters:
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* set - A reference to the bitset to set the CPU bit in
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* cpu - The bit number to be set
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* setlock - A reference to the lock protecting the set
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* orlock - Will be set to SP_LOCKED while holding setlock
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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#ifdef CONFIG_SMP
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void spin_setbit(FAR volatile cpu_set_t *set, unsigned int cpu,
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FAR volatile spinlock_t *setlock,
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FAR volatile spinlock_t *orlock)
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{
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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cpu_set_t prev;
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#endif
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irqstate_t flags;
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/* Disable local interrupts to prevent being re-entered from an interrupt
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* on the same CPU. This may not effect interrupt behavior on other CPUs.
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*/
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flags = up_irq_save();
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/* Then, get the 'setlock' spinlock */
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spin_lock(setlock);
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/* Then set the bit and mark the 'orlock' as locked */
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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prev = *set;
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#endif
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*set |= (1 << cpu);
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*orlock = SP_LOCKED;
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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if (prev == 0)
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{
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/* Notify that we have locked the spinlock */
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sched_note_spinlock(this_task(), orlock, NOTE_SPINLOCK_LOCKED);
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}
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#endif
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/* Release the 'setlock' and restore local interrupts */
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spin_unlock(setlock);
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up_irq_restore(flags);
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}
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#endif
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/****************************************************************************
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* Name: spin_clrbit
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*
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* Description:
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* Makes clearing a CPU bit in a bitset an atomic action
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*
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* Input Parameters:
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* set - A reference to the bitset to set the CPU bit in
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* cpu - The bit number to be set
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* setlock - A reference to the lock protecting the set
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* orlock - Will be set to SP_UNLOCKED if all bits become cleared in set
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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#ifdef CONFIG_SMP
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void spin_clrbit(FAR volatile cpu_set_t *set, unsigned int cpu,
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FAR volatile spinlock_t *setlock,
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FAR volatile spinlock_t *orlock)
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{
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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cpu_set_t prev;
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#endif
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irqstate_t flags;
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/* Disable local interrupts to prevent being re-entered from an interrupt
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* on the same CPU. This may not effect interrupt behavior on other CPUs.
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*/
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flags = up_irq_save();
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/* First, get the 'setlock' spinlock */
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spin_lock(setlock);
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/* Then clear the bit in the CPU set. Set/clear the 'orlock' depending
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* upon the resulting state of the CPU set.
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*/
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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prev = *set;
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#endif
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*set &= ~(1 << cpu);
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*orlock = (*set != 0) ? SP_LOCKED : SP_UNLOCKED;
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#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
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if (prev != 0 && *set == 0)
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{
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/* Notify that we have unlocked the spinlock */
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sched_note_spinlock(this_task(), orlock, NOTE_SPINLOCK_UNLOCK);
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}
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#endif
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/* Release the 'setlock' and restore local interrupts */
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spin_unlock(setlock);
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up_irq_restore(flags);
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}
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#endif
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#endif /* CONFIG_SPINLOCK */
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