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/* SPDX-License-Identifier: GPL-3.0-or-later */
/* Copyright 2021 - 2022, Kim Kuparinen < kimi.h.kuparinen@gmail.com > */
#ifndef APOS_LOCK_H
#define APOS_LOCK_H
/**
* @file lock.h
* Atomic locks, currently only \ref spin_lock() and \ref spin_unlock(). Mutex is
* probably overkill for this project.
*/
#include <apos/atomic.h>
#include <apos/irq.h>
/**
* Typedef for atomic_int.
*
* In apos, spinlocks are implemented with compiler-intrinsic atomic integers,
* that essentially just contain some flags. Currently all spinlocks
* enable/disable irqs.
*
* \todo irq contexts?
*/
typedef atomic_int spinlock_t;
#include <arch/lock.h>
/**
* Lock a spinlock.
*
* @param lck Pointer to lock.
*/
static inline void spin_lock(spinlock_t *lck)
{
disable_irq();
do {
while (atomic_load_explicit(lck, memory_order_acquire))
optional_pause();
} while (atomic_exchange_explicit(lck, 1, memory_order_acq_rel));
}
/**
* Unlock a spinlock.
*
* @param lck Pointer to lock.
*/
static inline void spin_unlock(spinlock_t *lck)
{
atomic_store_explicit(lck, 0, memory_order_release);
enable_irq();
}
#endif /* APOS_LOCK_H */
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