Add qemu 2.4.0

[kvmfornfv.git] / qemu / include / exec / spinlock.h

diff --git a/qemu/include/exec/spinlock.h b/qemu/include/exec/spinlock.h
new file mode 100644 (file)
index 0000000..a72edda
--- /dev/null
+++ b/qemu/include/exec/spinlock.h
@@ -0,0 +1,49 @@
+/*
+ *  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