1 files changed, 41 insertions, 3 deletions
diff --git a/lib/nostd/sail_spinlock.h b/lib/nostd/sail_spinlock.h
index 5e776b46..d69672dd 100644
--- a/lib/nostd/sail_spinlock.h
+++ b/lib/nostd/sail_spinlock.h
@@ -1,10 +1,48 @@
+/*
+ * Copyright 2018 The Hafnium Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 #ifndef __SAIL_SPINLOCK__
 #define __SAIL_SPINLOCK__
 
-int sail_spin_unlock(volatile int *lock);
+#include <stdatomic.h>
+
+struct sail_spinlock {
+	atomic_flag v;
+};
+
+#define SPINLOCK_INIT                 \
+	{                             \
+		.v = ATOMIC_FLAG_INIT \
+	}
+
+static inline void sail_spin_init(struct sail_spinlock *l)
+{
+        *l = (struct sail_spinlock)SPINLOCK_INIT;
+}
 
-int sail_spin_lock(volatile int *lock);
+static inline void sail_spin_lock(struct sail_spinlock *l)
+{
+	while (atomic_flag_test_and_set_explicit(&l->v, memory_order_acquire)) {
+		/* do nothing */
+	}
+}
 
-int sail_spin_trylock(volatile int *lock);
+static inline void sail_spin_unlock(struct sail_spinlock *l)
+{
+	atomic_flag_clear_explicit(&l->v, memory_order_release);
+}
 
 #endif