403 lines
11 KiB
C
403 lines
11 KiB
C
/****************************************************************************
|
|
* sched/semaphore/spinlock.c
|
|
*
|
|
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* 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.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
|
|
* COPYRIGHT OWNER 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.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <sched.h>
|
|
#include <assert.h>
|
|
|
|
#include <nuttx/spinlock.h>
|
|
#include <nuttx/sched_note.h>
|
|
#include <arch/irq.h>
|
|
|
|
#include "sched/sched.h"
|
|
|
|
#ifdef CONFIG_SPINLOCK
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: spin_lock
|
|
*
|
|
* Description:
|
|
* If this CPU does not already hold the spinlock, then loop until the
|
|
* spinlock is successfully locked.
|
|
*
|
|
* This implementation is non-reentrant and is prone to deadlocks in
|
|
* the case that any logic on the same CPU attempts to take the lock
|
|
* more than one
|
|
*
|
|
* Input Parameters:
|
|
* lock - A reference to the spinlock object to lock.
|
|
*
|
|
* Returned Value:
|
|
* None. When the function returns, the spinlock was successfully locked
|
|
* by this CPU.
|
|
*
|
|
* Assumptions:
|
|
* Not running at the interrupt level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void spin_lock(FAR volatile spinlock_t *lock)
|
|
{
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
/* Notify that we are waiting for a spinlock */
|
|
|
|
sched_note_spinlock(this_task(), lock);
|
|
#endif
|
|
|
|
while (up_testset(lock) == SP_LOCKED)
|
|
{
|
|
SP_DSB();
|
|
SP_WFE();
|
|
}
|
|
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
/* Notify that we have the spinlock */
|
|
|
|
sched_note_spinlocked(this_task(), lock);
|
|
#endif
|
|
SP_DMB();
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: spin_lock_wo_note
|
|
*
|
|
* Description:
|
|
* If this CPU does not already hold the spinlock, then loop until the
|
|
* spinlock is successfully locked.
|
|
*
|
|
* This implementation is the same as the above spin_lock() except that
|
|
* it does not perform instrumentation logic.
|
|
*
|
|
* Input Parameters:
|
|
* lock - A reference to the spinlock object to lock.
|
|
*
|
|
* Returned Value:
|
|
* None. When the function returns, the spinlock was successfully locked
|
|
* by this CPU.
|
|
*
|
|
* Assumptions:
|
|
* Not running at the interrupt level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void spin_lock_wo_note(FAR volatile spinlock_t *lock)
|
|
{
|
|
while (up_testset(lock) == SP_LOCKED)
|
|
{
|
|
SP_DSB();
|
|
SP_WFE();
|
|
}
|
|
|
|
SP_DMB();
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: spin_trylock
|
|
*
|
|
* Description:
|
|
* Try once to lock the spinlock. Do not wait if the spinlock is already
|
|
* locked.
|
|
*
|
|
* Input Parameters:
|
|
* lock - A reference to the spinlock object to lock.
|
|
*
|
|
* Returned Value:
|
|
* SP_LOCKED - Failure, the spinlock was already locked
|
|
* SP_UNLOCKED - Success, the spinlock was successfully locked
|
|
*
|
|
* Assumptions:
|
|
* Not running at the interrupt level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
spinlock_t spin_trylock(FAR volatile spinlock_t *lock)
|
|
{
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
/* Notify that we are waiting for a spinlock */
|
|
|
|
sched_note_spinlock(this_task(), lock);
|
|
#endif
|
|
|
|
if (up_testset(lock) == SP_LOCKED)
|
|
{
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
/* Notify that we abort for a spinlock */
|
|
|
|
sched_note_spinabort(this_task(), &lock);
|
|
#endif
|
|
SP_DSB();
|
|
return SP_LOCKED;
|
|
}
|
|
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
/* Notify that we have the spinlock */
|
|
|
|
sched_note_spinlocked(this_task(), lock);
|
|
#endif
|
|
SP_DMB();
|
|
return SP_UNLOCKED;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: spin_trylock_wo_note
|
|
*
|
|
* Description:
|
|
* Try once to lock the spinlock. Do not wait if the spinlock is already
|
|
* locked.
|
|
*
|
|
* This implementation is the same as the above spin_trylock() except that
|
|
* it does not perform instrumentation logic.
|
|
*
|
|
* Input Parameters:
|
|
* lock - A reference to the spinlock object to lock.
|
|
*
|
|
* Returned Value:
|
|
* SP_LOCKED - Failure, the spinlock was already locked
|
|
* SP_UNLOCKED - Success, the spinlock was successfully locked
|
|
*
|
|
* Assumptions:
|
|
* Not running at the interrupt level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
spinlock_t spin_trylock_wo_note(FAR volatile spinlock_t *lock)
|
|
{
|
|
if (up_testset(lock) == SP_LOCKED)
|
|
{
|
|
SP_DSB();
|
|
return SP_LOCKED;
|
|
}
|
|
|
|
SP_DMB();
|
|
return SP_UNLOCKED;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: spin_unlock
|
|
*
|
|
* Description:
|
|
* Release one count on a non-reentrant spinlock.
|
|
*
|
|
* Input Parameters:
|
|
* lock - A reference to the spinlock object to unlock.
|
|
*
|
|
* Returned Value:
|
|
* None.
|
|
*
|
|
* Assumptions:
|
|
* Not running at the interrupt level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifdef __SP_UNLOCK_FUNCTION
|
|
void spin_unlock(FAR volatile spinlock_t *lock)
|
|
{
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
/* Notify that we are unlocking the spinlock */
|
|
|
|
sched_note_spinunlock(this_task(), lock);
|
|
#endif
|
|
|
|
SP_DMB();
|
|
*lock = SP_UNLOCKED;
|
|
SP_DSB();
|
|
SP_SEV();
|
|
}
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Name: spin_unlock_wo_note
|
|
*
|
|
* Description:
|
|
* Release one count on a non-reentrant spinlock.
|
|
*
|
|
* This implementation is the same as the above spin_unlock() except that
|
|
* it does not perform instrumentation logic.
|
|
*
|
|
* Input Parameters:
|
|
* lock - A reference to the spinlock object to unlock.
|
|
*
|
|
* Returned Value:
|
|
* None.
|
|
*
|
|
* Assumptions:
|
|
* Not running at the interrupt level.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void spin_unlock_wo_note(FAR volatile spinlock_t *lock)
|
|
{
|
|
SP_DMB();
|
|
*lock = SP_UNLOCKED;
|
|
SP_DSB();
|
|
SP_SEV();
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: spin_setbit
|
|
*
|
|
* Description:
|
|
* Makes setting a CPU bit in a bitset an atomic action
|
|
*
|
|
* Input Parameters:
|
|
* set - A reference to the bitset to set the CPU bit in
|
|
* cpu - The bit number to be set
|
|
* setlock - A reference to the lock protecting the set
|
|
* orlock - Will be set to SP_LOCKED while holding setlock
|
|
*
|
|
* Returned Value:
|
|
* None
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifdef CONFIG_SMP
|
|
void spin_setbit(FAR volatile cpu_set_t *set, unsigned int cpu,
|
|
FAR volatile spinlock_t *setlock,
|
|
FAR volatile spinlock_t *orlock)
|
|
{
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
cpu_set_t prev;
|
|
#endif
|
|
irqstate_t flags;
|
|
|
|
/* Disable local interrupts to prevent being re-entered from an interrupt
|
|
* on the same CPU. This may not effect interrupt behavior on other CPUs.
|
|
*/
|
|
|
|
flags = up_irq_save();
|
|
|
|
/* Then, get the 'setlock' spinlock */
|
|
|
|
spin_lock(setlock);
|
|
|
|
/* Then set the bit and mark the 'orlock' as locked */
|
|
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
prev = *set;
|
|
#endif
|
|
*set |= (1 << cpu);
|
|
*orlock = SP_LOCKED;
|
|
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
if (prev == 0)
|
|
{
|
|
/* Notify that we have locked the spinlock */
|
|
|
|
sched_note_spinlocked(this_task(), orlock);
|
|
}
|
|
#endif
|
|
|
|
/* Release the 'setlock' and restore local interrupts */
|
|
|
|
spin_unlock(setlock);
|
|
up_irq_restore(flags);
|
|
}
|
|
#endif
|
|
|
|
/****************************************************************************
|
|
* Name: spin_clrbit
|
|
*
|
|
* Description:
|
|
* Makes clearing a CPU bit in a bitset an atomic action
|
|
*
|
|
* Input Parameters:
|
|
* set - A reference to the bitset to set the CPU bit in
|
|
* cpu - The bit number to be set
|
|
* setlock - A reference to the lock protecting the set
|
|
* orlock - Will be set to SP_UNLOCKED if all bits become cleared in set
|
|
*
|
|
* Returned Value:
|
|
* None
|
|
*
|
|
****************************************************************************/
|
|
|
|
#ifdef CONFIG_SMP
|
|
void spin_clrbit(FAR volatile cpu_set_t *set, unsigned int cpu,
|
|
FAR volatile spinlock_t *setlock,
|
|
FAR volatile spinlock_t *orlock)
|
|
{
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
cpu_set_t prev;
|
|
#endif
|
|
irqstate_t flags;
|
|
|
|
/* Disable local interrupts to prevent being re-entered from an interrupt
|
|
* on the same CPU. This may not effect interrupt behavior on other CPUs.
|
|
*/
|
|
|
|
flags = up_irq_save();
|
|
|
|
/* First, get the 'setlock' spinlock */
|
|
|
|
spin_lock(setlock);
|
|
|
|
/* Then clear the bit in the CPU set. Set/clear the 'orlock' depending
|
|
* upon the resulting state of the CPU set.
|
|
*/
|
|
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
prev = *set;
|
|
#endif
|
|
*set &= ~(1 << cpu);
|
|
*orlock = (*set != 0) ? SP_LOCKED : SP_UNLOCKED;
|
|
|
|
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
|
|
if (prev != 0 && *set == 0)
|
|
{
|
|
/* Notify that we have unlocked the spinlock */
|
|
|
|
sched_note_spinunlock(this_task(), orlock);
|
|
}
|
|
#endif
|
|
|
|
/* Release the 'setlock' and restore local interrupts */
|
|
|
|
spin_unlock(setlock);
|
|
up_irq_restore(flags);
|
|
}
|
|
#endif
|
|
|
|
#endif /* CONFIG_SPINLOCK */
|