diff --git a/include/common/aarch32/asm_macros.S b/include/common/aarch32/asm_macros.S
index 23122f3..45023a0 100644
--- a/include/common/aarch32/asm_macros.S
+++ b/include/common/aarch32/asm_macros.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -32,6 +32,7 @@
 
 #include <arch.h>
 #include <asm_macros_common.S>
+#include <spinlock.h>
 
 #define WORD_SIZE	4
 
@@ -124,4 +125,13 @@
 #endif
 	.endm
 
+	/*
+	 * Reserve space for a spin lock in assembly file.
+	 */
+	.macro define_asm_spinlock _name:req
+	.align	SPINLOCK_ASM_ALIGN
+	\_name:
+	.space	SPINLOCK_ASM_SIZE
+	.endm
+
 #endif /* __ASM_MACROS_S__ */
diff --git a/include/common/aarch64/asm_macros.S b/include/common/aarch64/asm_macros.S
index 88e8d9c..b0f3a0d 100644
--- a/include/common/aarch64/asm_macros.S
+++ b/include/common/aarch64/asm_macros.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -32,6 +32,7 @@
 
 #include <arch.h>
 #include <asm_macros_common.S>
+#include <spinlock.h>
 
 
 	.macro	func_prologue
@@ -200,4 +201,13 @@
 #endif
 	.endm
 
+	/*
+	 * Reserve space for a spin lock in assembly file.
+	 */
+	.macro define_asm_spinlock _name:req
+	.align	SPINLOCK_ASM_ALIGN
+	\_name:
+	.space	SPINLOCK_ASM_SIZE
+	.endm
+
 #endif /* __ASM_MACROS_S__ */
diff --git a/include/lib/spinlock.h b/include/lib/spinlock.h
index cb0bc3e..8273c78 100644
--- a/include/lib/spinlock.h
+++ b/include/lib/spinlock.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -31,11 +31,23 @@
 #ifndef __SPINLOCK_H__
 #define __SPINLOCK_H__
 
+#ifndef __ASSEMBLY__
+
+#include <types.h>
+
 typedef struct spinlock {
-	volatile unsigned int lock;
+	volatile uint32_t lock;
 } spinlock_t;
 
 void spin_lock(spinlock_t *lock);
 void spin_unlock(spinlock_t *lock);
 
+#else
+
+/* Spin lock definitions for use in assembly */
+#define SPINLOCK_ASM_ALIGN	2
+#define SPINLOCK_ASM_SIZE	4
+
+#endif
+
 #endif /* __SPINLOCK_H__ */