1/* Copyright (C) 2005-2015 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU Offloading and Multi Processing Library 5 (libgomp). 6 7 Libgomp is free software; you can redistribute it and/or modify it 8 under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3, or (at your option) 10 any later version. 11 12 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 14 FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15 more details. 16 17 Under Section 7 of GPL version 3, you are granted additional 18 permissions described in the GCC Runtime Library Exception, version 19 3.1, as published by the Free Software Foundation. 20 21 You should have received a copy of the GNU General Public License and 22 a copy of the GCC Runtime Library Exception along with this program; 23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 <http://www.gnu.org/licenses/>. */ 25 26/* This is a Linux specific implementation of a mutex synchronization 27 mechanism for libgomp. This type is private to the library. This 28 implementation uses atomic instructions and the futex syscall. */ 29 30#ifndef GOMP_MUTEX_H 31#define GOMP_MUTEX_H 1 32 33typedef int gomp_mutex_t; 34 35#define GOMP_MUTEX_INIT_0 1 36 37extern void gomp_mutex_lock_slow (gomp_mutex_t *mutex, int); 38extern void gomp_mutex_unlock_slow (gomp_mutex_t *mutex); 39 40static inline void 41gomp_mutex_init (gomp_mutex_t *mutex) 42{ 43 *mutex = 0; 44} 45 46static inline void 47gomp_mutex_destroy (gomp_mutex_t *mutex) 48{ 49} 50 51static inline void 52gomp_mutex_lock (gomp_mutex_t *mutex) 53{ 54 int oldval = 0; 55 if (!__atomic_compare_exchange_n (mutex, &oldval, 1, false, 56 MEMMODEL_ACQUIRE, MEMMODEL_RELAXED)) 57 gomp_mutex_lock_slow (mutex, oldval); 58} 59 60static inline void 61gomp_mutex_unlock (gomp_mutex_t *mutex) 62{ 63 int wait = __atomic_exchange_n (mutex, 0, MEMMODEL_RELEASE); 64 if (__builtin_expect (wait < 0, 0)) 65 gomp_mutex_unlock_slow (mutex); 66} 67#endif /* GOMP_MUTEX_H */ 68