qemu-lock.h

   1 /*
   2  *  Copyright (c) 2003 Fabrice Bellard
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, see <http://www.gnu.org/licenses/>
  16  */
  17
  18 /* configure guarantees us that we have pthreads on any host except
  19  * mingw32, which doesn't support any of the user-only targets.
  20  * So we can simply assume we have pthread mutexes here.
  21  */
  22 #if defined(CONFIG_USER_ONLY)
  23
  24 #include <pthread.h>
  25 #define spin_lock pthread_mutex_lock
  26 #define spin_unlock pthread_mutex_unlock
  27 #define spinlock_t pthread_mutex_t
  28 #define SPIN_LOCK_UNLOCKED PTHREAD_MUTEX_INITIALIZER
  29
  30 #else
  31
  32 /* Empty implementations, on the theory that system mode emulation
  33  * is single-threaded. This means that these functions should only
  34  * be used from code run in the TCG cpu thread, and cannot protect
  35  * data structures which might also be accessed from the IO thread
  36  * or from signal handlers.
  37  */
  38 typedef int spinlock_t;
  39 #define SPIN_LOCK_UNLOCKED 0
  40
  41 static inline void spin_lock(spinlock_t *lock)
  42 {
  43 }
  44
  45 static inline void spin_unlock(spinlock_t *lock)
  46 {
  47 }
  48
  49 #endif