| /* Copyright (C) 2005-2019 Free Software Foundation, Inc. |
| Contributed by Richard Henderson <rth@redhat.com>. |
| |
| This file is part of the GNU Offloading and Multi Processing Library |
| (libgomp). |
| |
| Libgomp 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, or (at your option) |
| any later version. |
| |
| Libgomp 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. |
| |
| Under Section 7 of GPL version 3, you are granted additional |
| permissions described in the GCC Runtime Library Exception, version |
| 3.1, as published by the Free Software Foundation. |
| |
| You should have received a copy of the GNU General Public License and |
| a copy of the GCC Runtime Library Exception along with this program; |
| see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* This is a Linux specific implementation of a mutex synchronization |
| mechanism for libgomp. This type is private to the library. This |
| implementation uses atomic instructions and the futex syscall. */ |
| |
| #ifndef GOMP_MUTEX_H |
| #define GOMP_MUTEX_H 1 |
| |
| typedef int gomp_mutex_t; |
| |
| #define GOMP_MUTEX_INIT_0 1 |
| |
| extern void gomp_mutex_lock_slow (gomp_mutex_t *mutex, int); |
| extern void gomp_mutex_unlock_slow (gomp_mutex_t *mutex); |
| |
| static inline void |
| gomp_mutex_init (gomp_mutex_t *mutex) |
| { |
| *mutex = 0; |
| } |
| |
| static inline void |
| gomp_mutex_destroy (gomp_mutex_t *mutex) |
| { |
| } |
| |
| static inline void |
| gomp_mutex_lock (gomp_mutex_t *mutex) |
| { |
| int oldval = 0; |
| if (!__atomic_compare_exchange_n (mutex, &oldval, 1, false, |
| MEMMODEL_ACQUIRE, MEMMODEL_RELAXED)) |
| gomp_mutex_lock_slow (mutex, oldval); |
| } |
| |
| static inline void |
| gomp_mutex_unlock (gomp_mutex_t *mutex) |
| { |
| int wait = __atomic_exchange_n (mutex, 0, MEMMODEL_RELEASE); |
| if (__builtin_expect (wait < 0, 0)) |
| gomp_mutex_unlock_slow (mutex); |
| } |
| #endif /* GOMP_MUTEX_H */ |