qemu/include/exec/spinlock.h

50 lines
1.6 KiB
C

/*
* Copyright (c) 2003 Fabrice Bellard
*
* This library 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 2 of the License, or (at your option) any later version.
*
* This library 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 library; if not, see <http://www.gnu.org/licenses/>
*/
/* configure guarantees us that we have pthreads on any host except
* mingw32, which doesn't support any of the user-only targets.
* So we can simply assume we have pthread mutexes here.
*/
#if defined(CONFIG_USER_ONLY)
#include <pthread.h>
#define spin_lock pthread_mutex_lock
#define spin_unlock pthread_mutex_unlock
#define spinlock_t pthread_mutex_t
#define SPIN_LOCK_UNLOCKED PTHREAD_MUTEX_INITIALIZER
#else
/* Empty implementations, on the theory that system mode emulation
* is single-threaded. This means that these functions should only
* be used from code run in the TCG cpu thread, and cannot protect
* data structures which might also be accessed from the IO thread
* or from signal handlers.
*/
typedef int spinlock_t;
#define SPIN_LOCK_UNLOCKED 0
static inline void spin_lock(spinlock_t *lock)
{
}
static inline void spin_unlock(spinlock_t *lock)
{
}
#endif