Implement basic kernel spinlock mechanism

xtoskrnl/ke/spinlock.c

@@ -9,6 +9,53 @@
 #include <xtos.h>
 
 
+/**
+ * Acquires a specified queued spinlock.
+ *
+ * @param LockLevel
+ *        Supplies the queued spinlock level.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+VOID
+KeAcquireQueuedSpinLock(IN KSPIN_LOCK_QUEUE_LEVEL LockLevel)
+{
+    /* Acquire the queued spinlock */
+    KeAcquireSpinLock(KeGetCurrentProcessorControlBlock()->LockQueue[LockLevel].Lock);
+}
+
+/**
+ * Acquires a kernel spin lock.
+ *
+ * @param SpinLock
+ *        Supplies a pointer to the kernel spin lock.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+VOID
+KeAcquireSpinLock(IN OUT PKSPIN_LOCK SpinLock)
+{
+    /* Try to acquire the lock */
+    while(RtlAtomicBitTestAndSet((PLONG)SpinLock, 0))
+    {
+        /* Wait until locked is cleared */
+        while(*(VOLATILE PKSPIN_LOCK)SpinLock & 1)
+        {
+                /* Yield processor and keep waiting */
+                ArYieldProcessor();
+        }
+    }
+
+    /* Add an explicit memory barrier */
+    ArReadWriteBarrier();
+}
+
 /**
  * Initializes a kernel spinlock object.
  *
@@ -26,3 +73,42 @@ KeInitializeSpinLock(IN PKSPIN_LOCK SpinLock)
     /* Zero initialize spinlock */
     *SpinLock = 0;
 }
+
+/**
+ * Releases a queued spinlock.
+ *
+ * @param LockLevel
+ *        Supplies the queued spinlock level.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+VOID
+KeReleaseQueuedSpinLock(IN KSPIN_LOCK_QUEUE_LEVEL LockLevel)
+{
+    /* Clear the lock */
+    KeReleaseSpinLock(KeGetCurrentProcessorControlBlock()->LockQueue[LockLevel].Lock);
+}
+
+/**
+ * Releases a kernel spin lock.
+ *
+ * @param SpinLock
+ *        Supplies a pointer to the kernel spin lock.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTFASTCALL
+VOID
+KeReleaseSpinLock(IN OUT PKSPIN_LOCK SpinLock)
+{
+    /* Clear the lock */
+    RtlAtomicAnd32((PLONG)SpinLock, 0);
+
+    /* Add an explicit memory barrier */
+    ArReadWriteBarrier();
+}