implement clone on the sync primitives

kernel/rustkernel/src/sync/lock.rs

@@ -77,6 +77,14 @@ impl Default for Lock {
         Lock::new()
     }
 }
+impl Clone for Lock {
+    fn clone(&self) -> Self {
+        Lock {
+            locked: AtomicBool::new(self.locked.load(Ordering::SeqCst)),
+            lock_strategy: UnsafeCell::new(self.lock_strategy()),
+        }
+    }
+}
 unsafe impl Sync for Lock {}
 
 pub struct LockGuard<'l> {

kernel/rustkernel/src/sync/mutex.rs

@@ -42,6 +42,12 @@ impl<T> Mutex<T> {
     }
 }
 unsafe impl<T> Sync for Mutex<T> where T: Send {}
+impl<T> Clone for Mutex<T> where T: Clone {
+    fn clone(&self) -> Self {
+        let value: T = self.lock_spinning().as_ref().clone();
+        Mutex::new(value)
+    }
+}
 
 pub struct MutexGuard<'m, T> {
     pub mutex: &'m Mutex<T>,

kernel/rustkernel/src/sync/sleeplock.rs

@@ -34,6 +34,13 @@ impl Sleeplock {
         wakeup(addr_of!(*self).cast_mut().cast());
     }
 }
+impl Clone for Sleeplock {
+    fn clone(&self) -> Self {
+        Sleeplock {
+            locked: AtomicBool::new(self.locked.load(Ordering::SeqCst)),
+        }
+    }
+}
 
 pub struct SleeplockGuard<'l> {
     pub lock: &'l Sleeplock,

kernel/rustkernel/src/sync/spinlock.rs

@@ -42,6 +42,13 @@ impl Spinlock {
         pop_intr_off();
     }
 }
+impl Clone for Spinlock {
+    fn clone(&self) -> Self {
+        Spinlock {
+            locked: AtomicBool::new(self.locked.load(Ordering::SeqCst)),
+        }
+    }
+}
 
 pub struct SpinlockGuard<'l> {
     pub lock: &'l Spinlock,