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/*
* Copyright (c) 2012-2017 Richard Braun.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _KERN_SPINLOCK_I_H
#define _KERN_SPINLOCK_I_H
#include <kern/assert.h>
#include <kern/error.h>
#include <kern/spinlock_types.h>
#include <machine/atomic.h>
#include <machine/cpu.h>
static inline int
spinlock_tryacquire(struct spinlock *lock)
{
unsigned int state;
state = atomic_swap_uint(&lock->locked, 1);
if (state == 0) {
return 0;
}
return ERROR_BUSY;
}
static inline void
spinlock_acquire(struct spinlock *lock)
{
int error;
for (;;) {
error = spinlock_tryacquire(lock);
if (!error) {
break;
}
cpu_pause();
}
}
static inline void
spinlock_release(struct spinlock *lock)
{
unsigned int locked;
locked = atomic_swap_uint(&lock->locked, 0);
assert(locked);
}
#endif /* _KERN_SPINLOCK_I_H */
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