nuttx/sched/semaphore/spinlock.c
Xiang Xiao b2f75c2f3d spinlock: Move the inclusion of stdatomic.h to source file
to make rwlock work with c++ source code

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
2023-11-19 20:22:50 +01:00

685 lines
18 KiB
C

/****************************************************************************
* sched/semaphore/spinlock.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdatomic.h>
#include <sched.h>
#include <assert.h>
#include <nuttx/spinlock.h>
#include <nuttx/sched_note.h>
#include <arch/irq.h>
#if defined(CONFIG_TICKET_SPINLOCK) || defined(CONFIG_RW_SPINLOCK)
# include <stdatomic.h>
#endif
#include "sched/sched.h"
#if defined(CONFIG_SPINLOCK) || defined(CONFIG_TICKET_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 once.
*
* 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, NOTE_SPINLOCK_LOCK);
#endif
#ifdef CONFIG_TICKET_SPINLOCK
unsigned short ticket =
atomic_fetch_add((FAR atomic_ushort *)&lock->tickets.next, 1);
while (atomic_load((FAR atomic_ushort *)&lock->tickets.owner) != ticket)
#else /* CONFIG_SPINLOCK */
while (up_testset(lock) == SP_LOCKED)
#endif
{
SP_DSB();
SP_WFE();
}
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
/* Notify that we have the spinlock */
sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_LOCKED);
#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)
{
#ifdef CONFIG_TICKET_SPINLOCK
unsigned short ticket =
atomic_fetch_add((FAR atomic_ushort *)&lock->tickets.next, 1);
while (atomic_load((FAR atomic_ushort *)&lock->tickets.owner) != ticket)
#else /* CONFIG_TICKET_SPINLOCK */
while (up_testset(lock) == SP_LOCKED)
#endif
{
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:
* false - Failure, the spinlock was already locked
* true - Success, the spinlock was successfully locked
*
* Assumptions:
* Not running at the interrupt level.
*
****************************************************************************/
bool 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, NOTE_SPINLOCK_LOCK);
#endif
#ifdef CONFIG_TICKET_SPINLOCK
unsigned short ticket =
atomic_load((FAR atomic_ushort *)&lock->tickets.next);
spinlock_t old =
{
{
ticket, ticket
}
};
spinlock_t new =
{
{
ticket, ticket + 1
}
};
if (!atomic_compare_exchange_strong((FAR atomic_uint *)&lock->value,
&old.value, new.value))
#else /* CONFIG_TICKET_SPINLOCK */
if (up_testset(lock) == SP_LOCKED)
#endif /* CONFIG_TICKET_SPINLOCK */
{
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
/* Notify that we abort for a spinlock */
sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_ABORT);
#endif
SP_DSB();
return false;
}
#ifdef CONFIG_SCHED_INSTRUMENTATION_SPINLOCKS
/* Notify that we have the spinlock */
sched_note_spinlock(this_task(), lock, NOTE_SPINLOCK_LOCKED);
#endif
SP_DMB();
return true;
}
/****************************************************************************
* 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:
* false - Failure, the spinlock was already locked
* true - Success, the spinlock was successfully locked
*
* Assumptions:
* Not running at the interrupt level.
*
****************************************************************************/
bool spin_trylock_wo_note(FAR volatile spinlock_t *lock)
{
#ifdef CONFIG_TICKET_SPINLOCK
unsigned short ticket =
atomic_load((FAR atomic_ushort *)&lock->tickets.next);
spinlock_t old =
{
{
ticket, ticket
}
};
spinlock_t new =
{
{
ticket, ticket + 1
}
};
if (!atomic_compare_exchange_strong((FAR atomic_uint *)&lock->value,
&old.value, new.value))
#else /* CONFIG_TICKET_SPINLOCK */
if (up_testset(lock) == SP_LOCKED)
#endif /* CONFIG_TICKET_SPINLOCK */
{
SP_DSB();
return false;
}
SP_DMB();
return true;
}
/****************************************************************************
* 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_spinlock(this_task(), lock, NOTE_SPINLOCK_UNLOCK);
#endif
SP_DMB();
#ifdef CONFIG_TICKET_SPINLOCK
atomic_fetch_add((FAR atomic_ushort *)&lock->tickets.owner, 1);
#else
*lock = SP_UNLOCKED;
#endif
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();
#ifdef CONFIG_TICKET_SPINLOCK
atomic_fetch_add((FAR atomic_ushort *)&lock->tickets.owner, 1);
#else
*lock = SP_UNLOCKED;
#endif
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_spinlock(this_task(), orlock, NOTE_SPINLOCK_LOCKED);
}
#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_spinlock(this_task(), orlock, NOTE_SPINLOCK_UNLOCK);
}
#endif
/* Release the 'setlock' and restore local interrupts */
spin_unlock(setlock);
up_irq_restore(flags);
}
#endif
#ifdef CONFIG_RW_SPINLOCK
/****************************************************************************
* Name: read_lock
*
* Description:
* If this task does not already hold the spinlock, then loop until the
* spinlock is successfully locked.
*
* This implementation is non-reentrant and set a bit of lock.
*
* The priority of reader is higher than writter if a reader hold the
* lock, a new reader can get its lock but writer can't get this lock.
*
* 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 read_lock(FAR volatile rwlock_t *lock)
{
while (true)
{
int old = atomic_load((FAR atomic_int *)lock);
if (old <= RW_SP_WRITE_LOCKED)
{
DEBUGASSERT(old == RW_SP_WRITE_LOCKED);
SP_DSB();
SP_WFE();
}
else if(atomic_compare_exchange_strong((FAR atomic_int *)lock,
&old, old + 1))
{
break;
}
}
SP_DMB();
}
/****************************************************************************
* Name: read_trylock
*
* Description:
* If this task does not already hold the spinlock, then try to get the
* lock.
*
* This implementation is non-reentrant and set a bit of lock.
*
* The priority of reader is higher than writter if a reader hold the
* lock, a new reader can get its lock but writer can't get this lock.
*
* Input Parameters:
* lock - A reference to the spinlock object to lock.
*
* Returned Value:
* false - Failure, the spinlock was already locked
* true - Success, the spinlock was successfully locked
*
* Assumptions:
* Not running at the interrupt level.
*
****************************************************************************/
bool read_trylock(FAR volatile rwlock_t *lock)
{
while (true)
{
int old = atomic_load((FAR atomic_int *)lock);
if (old <= RW_SP_WRITE_LOCKED)
{
DEBUGASSERT(old == RW_SP_WRITE_LOCKED);
return false;
}
else if (atomic_compare_exchange_strong((FAR atomic_int *)lock,
&old, old + 1))
{
break;
}
}
SP_DMB();
return true;
}
/****************************************************************************
* Name: read_unlock
*
* Description:
* Release a bit 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.
*
****************************************************************************/
void read_unlock(FAR volatile rwlock_t *lock)
{
DEBUGASSERT(atomic_load((FAR atomic_int *)lock) >= RW_SP_READ_LOCKED);
SP_DMB();
atomic_fetch_sub((FAR atomic_int *)lock, 1);
SP_DSB();
SP_SEV();
}
/****************************************************************************
* Name: write_lock
*
* Description:
* If this task does not already hold the spinlock, then loop until the
* spinlock is successfully locked.
*
* This implementation is non-reentrant and set all bit on lock to avoid
* readers and writers.
*
* The priority of reader is higher than writter if a reader hold the
* lock, a new reader can get its lock but writer can't get this lock.
*
* 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 write_lock(FAR volatile rwlock_t *lock)
{
int zero = RW_SP_UNLOCKED;
while (!atomic_compare_exchange_strong((FAR atomic_int *)lock,
&zero, RW_SP_WRITE_LOCKED))
{
SP_DSB();
SP_WFE();
}
SP_DMB();
}
/****************************************************************************
* Name: write_trylock
*
* Description:
* If this task does not already hold the spinlock, then loop until the
* spinlock is successfully locked.
*
* This implementation is non-reentrant and set all bit on lock to avoid
* readers and writers.
*
* The priority of reader is higher than writter if a reader hold the
* lock, a new reader can get its lock but writer can't get this lock.
*
* Input Parameters:
* lock - A reference to the spinlock object to lock.
*
* Returned Value:
* false - Failure, the spinlock was already locked
* true - Success, the spinlock was successfully locked
*
* Assumptions:
* Not running at the interrupt level.
*
****************************************************************************/
bool write_trylock(FAR volatile rwlock_t *lock)
{
int zero = RW_SP_UNLOCKED;
if (atomic_compare_exchange_strong((FAR atomic_int *)lock,
&zero, RW_SP_WRITE_LOCKED))
{
SP_DMB();
return true;
}
SP_DSB();
return false;
}
/****************************************************************************
* Name: write_unlock
*
* Description:
* Release write lock 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.
*
****************************************************************************/
void write_unlock(FAR volatile rwlock_t *lock)
{
/* Ensure this cpu already get write lock */
DEBUGASSERT(atomic_load((FAR atomic_int *)lock) == RW_SP_WRITE_LOCKED);
SP_DMB();
atomic_store((FAR atomic_int *)lock, RW_SP_UNLOCKED);
SP_DSB();
SP_SEV();
}
#endif /* CONFIG_RW_SPINLOCK */
#endif /* CONFIG_SPINLOCK */