xnu-7195.50.7.100.1.tar.gz

[apple/xnu.git] / libkern / gen / OSSpinLock.c

diff --git a/libkern/gen/OSSpinLock.c b/libkern/gen/OSSpinLock.c
new file mode 100644 (file)
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+++ b/libkern/gen/OSSpinLock.c
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+/*
+ * Copyright (c) 2020 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ */
+
+#include <libkern/OSAtomic.h>
+#include <machine/atomic.h>
+
+_Static_assert(sizeof(int) == sizeof(OSSpinLock), "OSSpinLock size mismatch");
+
+void
+OSSpinLockUnlock(volatile OSSpinLock *lock)
+{
+       os_atomic_store(lock, 0, release);
+}
+
+Boolean
+OSSpinLockTry(volatile OSSpinLock *lock)
+{
+       return os_atomic_cmpxchg(lock, 0, 1, acquire);
+}