diff --git a/arch/arm/include/spinlock.h b/arch/arm/include/spinlock.h
index 44e405e6303..84800fbf8dc 100644
--- a/arch/arm/include/spinlock.h
+++ b/arch/arm/include/spinlock.h
@@ -48,9 +48,31 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* Spinlock states */
+
 #define SP_UNLOCKED 0  /* The Un-locked state */
 #define SP_LOCKED   1  /* The Locked state */
 
+/* Memory barriers for use with NuttX spinlock logic */
+
+#ifndef arm_isb
+#  define arm_isb(n) __asm__ __volatile__ ("isb " #n : : : "memory")
+#endif
+
+#define SP_ISB() arm_isb(15)
+
+#ifndef arm_dsb
+#  define arm_dsb(n) __asm__ __volatile__ ("dsb " #n : : : "memory")
+#endif
+
+#define SP_DSB() arm_dsb(15)
+
+#ifndef arm_dmb
+#  define arm_dmb(n) __asm__ __volatile__ ("dmb " #n : : : "memory")
+#endif
+
+#define SP_DMB() arm_dmb(15)
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
diff --git a/include/nuttx/spinlock.h b/include/nuttx/spinlock.h
index 65786a0c6d5..0a9cc88a5ea 100644
--- a/include/nuttx/spinlock.h
+++ b/include/nuttx/spinlock.h
@@ -203,8 +203,11 @@ void spin_lockr(FAR struct spinlock_s *lock);
  *
  ****************************************************************************/
 
-/* void spin_unlock(FAR spinlock_t *lock); */
-#define spin_unlock(l)  do { *(l) = SP_UNLOCKED; } while (0)
+#ifdef SP_DMB
+void spin_unlock(FAR volatile spinlock_t *lock);
+#else
+#  define spin_unlock(l)  do { *(l) = SP_UNLOCKED; } while (0)
+#endif
 
 /****************************************************************************
  * Name: spin_unlockr
diff --git a/sched/semaphore/spinlock.c b/sched/semaphore/spinlock.c
index 79d904e7efc..a3c5225adf4 100644
--- a/sched/semaphore/spinlock.c
+++ b/sched/semaphore/spinlock.c
@@ -65,6 +65,22 @@
 
 #undef CONFIG_SPINLOCK_LOCKDOWN /* Feature not yet available */
 
+/* Memory barriers may be provided in arch/spinlock.h
+ *
+ *   DMB - Data memory barrier.  Assures writes are completed to memory.
+ *   DSB - Data syncrhonization barrier.
+ */
+
+#define HAVE_DMB 1
+#ifndef SP_DMB
+#  define SP_DMB()
+#  undef HAVE_DMB
+#endif
+
+#ifndef SP_DSB
+#  define SP_DSB()
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -121,12 +137,37 @@ void spin_lock(FAR volatile spinlock_t *lock)
 {
   while (up_testset(lock) == SP_LOCKED)
     {
-#if 0 /* Would recurse */
-      sched_yield();
-#endif
+      SP_DSB();
     }
+
+  SP_DMB();
 }
 
+/****************************************************************************
+ * Name: spin_unlock
+ *
+ * Description:
+ *   Release one count on a non-reentrant spinlock.
+ *
+ * Input Parameters:
+ *   lock - A reference to the spinlock object to unlock.
+ *
+ * Returned Value:
+ *   None.
+ *
+ * Assumptions:
+ *   Not running at the interrupt level.
+ *
+ ****************************************************************************/
+
+#ifdef HAVE_DMB
+void spin_unlock(FAR volatile spinlock_t *lock)
+{
+  *lock = SP_UNLOCKED;
+  SP_DMB();
+}
+#endif
+
 /****************************************************************************
  * Name: spin_lockr
  *