qemu/qemu-lock.h
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   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 */
  38typedef int spinlock_t;
  39#define SPIN_LOCK_UNLOCKED 0
  40
  41static inline void spin_lock(spinlock_t *lock)
  42{
  43}
  44
  45static inline void spin_unlock(spinlock_t *lock)
  46{
  47}
  48
  49#endif
  50