--- /dev/null
+/* Copyright 2019 SiFive, Inc */
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include <metal/lock.h>
+
+extern inline int metal_lock_init(struct metal_lock *lock);
+extern inline int metal_lock_take(struct metal_lock *lock);
+extern inline int metal_lock_give(struct metal_lock *lock);