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- /* Copyright (C) 2014 Stony Brook University
- This file is part of Graphene Library OS.
- Graphene Library OS is free software: you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public License
- as published by the Free Software Foundation, either version 3 of the
- License, or (at your option) any later version.
- Graphene Library OS 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 Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /*
- * db_spinlock.c
- *
- * This file contains APIs that provide operations of (futex based) mutexes.
- * Based on "Mutexes and Condition Variables using Futexes"
- * (http://locklessinc.com/articles/mutex_cv_futex)
- */
- #include <atomic.h>
- #include <limits.h>
- #include "api.h"
- #include "pal.h"
- #include "pal_debug.h"
- #include "pal_defs.h"
- #include "pal_error.h"
- #include "pal_internal.h"
- #include "pal_linux.h"
- #include "pal_linux_defs.h"
- int _DkSpinLock(struct spinlock* lock) {
- struct atomic_int* m = &lock->value;
- while (1) {
- int c = atomic_read(m);
- if (!c && atomic_cmpxchg(m, 0, 1) == 0)
- break;
- CPU_RELAX();
- }
- return 0;
- }
- int _DkSpinUnlock(struct spinlock* lock) {
- struct atomic_int* m = &lock->value;
- atomic_set(m, 0);
- return 0;
- }
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