diff --git a/include/lib/cpus/aarch64/cpuamu.h b/include/lib/cpus/aarch64/cpuamu.h
index 960a524..921abdb 100644
--- a/include/lib/cpus/aarch64/cpuamu.h
+++ b/include/lib/cpus/aarch64/cpuamu.h
@@ -4,8 +4,8 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __CPUAMU_H__
-#define __CPUAMU_H__
+#ifndef CPUAMU_H
+#define CPUAMU_H
 
 /*******************************************************************************
  * CPU Activity Monitor Unit register specific definitions.
@@ -32,8 +32,8 @@
 #ifndef __ASSEMBLY__
 #include <stdint.h>
 
-uint64_t cpuamu_cnt_read(int idx);
-void cpuamu_cnt_write(int idx, uint64_t val);
+uint64_t cpuamu_cnt_read(unsigned int idx);
+void cpuamu_cnt_write(unsigned int idx, uint64_t val);
 unsigned int cpuamu_read_cpuamcntenset_el0(void);
 unsigned int cpuamu_read_cpuamcntenclr_el0(void);
 void cpuamu_write_cpuamcntenset_el0(unsigned int mask);
@@ -45,4 +45,4 @@
 
 #endif /* __ASSEMBLY__ */
 
-#endif /* __CPUAMU_H__ */
+#endif /* CPUAMU_H */
diff --git a/include/lib/extensions/amu.h b/include/lib/extensions/amu.h
index 46d5e15..1836fe5 100644
--- a/include/lib/extensions/amu.h
+++ b/include/lib/extensions/amu.h
@@ -4,33 +4,35 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __AMU_H__
-#define __AMU_H__
+#ifndef AMU_H
+#define AMU_H
 
 #include <cassert.h>
 #include <platform_def.h>
+#include <stdbool.h>
 #include <stdint.h>
+#include <utils_def.h>
 
 /* All group 0 counters */
-#define AMU_GROUP0_COUNTERS_MASK	0xf
+#define AMU_GROUP0_COUNTERS_MASK	U(0xf)
 
 #ifdef PLAT_AMU_GROUP1_COUNTERS_MASK
 #define AMU_GROUP1_COUNTERS_MASK	PLAT_AMU_GROUP1_COUNTERS_MASK
 #else
-#define AMU_GROUP1_COUNTERS_MASK	0
+#define AMU_GROUP1_COUNTERS_MASK	U(0)
 #endif
 
 #ifdef PLAT_AMU_GROUP1_NR_COUNTERS
 #define AMU_GROUP1_NR_COUNTERS		PLAT_AMU_GROUP1_NR_COUNTERS
 #else
-#define AMU_GROUP1_NR_COUNTERS		0
+#define AMU_GROUP1_NR_COUNTERS		U(0)
 #endif
 
 CASSERT(AMU_GROUP1_COUNTERS_MASK <= 0xffff, invalid_amu_group1_counters_mask);
 CASSERT(AMU_GROUP1_NR_COUNTERS <= 16, invalid_amu_group1_nr_counters);
 
-int amu_supported(void);
-void amu_enable(int el2_unused);
+bool amu_supported(void);
+void amu_enable(bool el2_unused);
 
 /* Group 0 configuration helpers */
 uint64_t amu_group0_cnt_read(int idx);
@@ -41,4 +43,4 @@
 void amu_group1_cnt_write(int idx, uint64_t val);
 void amu_group1_set_evtype(int idx, unsigned int val);
 
-#endif /* __AMU_H__ */
+#endif /* AMU_H */
diff --git a/include/lib/extensions/amu_private.h b/include/lib/extensions/amu_private.h
index 0c660bb..ab4e6aa 100644
--- a/include/lib/extensions/amu_private.h
+++ b/include/lib/extensions/amu_private.h
@@ -1,19 +1,19 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __AMU_PRIVATE_H__
-#define __AMU_PRIVATE_H__
+#ifndef AMU_PRIVATE_H
+#define AMU_PRIVATE_H
 
 #include <stdint.h>
 
 uint64_t amu_group0_cnt_read_internal(int idx);
-void amu_group0_cnt_write_internal(int idx, uint64_t);
+void amu_group0_cnt_write_internal(int idx, uint64_t val);
 
 uint64_t amu_group1_cnt_read_internal(int idx);
-void amu_group1_cnt_write_internal(int idx, uint64_t);
+void amu_group1_cnt_write_internal(int idx, uint64_t val);
 void amu_group1_set_evtype_internal(int idx, unsigned int val);
 
-#endif /* __AMU_PRIVATE_H__ */
+#endif /* AMU_PRIVATE_H */
diff --git a/include/lib/extensions/mpam.h b/include/lib/extensions/mpam.h
index 571b96b..ac8c00a 100644
--- a/include/lib/extensions/mpam.h
+++ b/include/lib/extensions/mpam.h
@@ -10,6 +10,6 @@
 #include <stdbool.h>
 
 bool mpam_supported(void);
-void mpam_enable(int el2_unused);
+void mpam_enable(bool el2_unused);
 
 #endif /* MPAM_H */
diff --git a/include/lib/extensions/spe.h b/include/lib/extensions/spe.h
index b2b188e..d4b925f 100644
--- a/include/lib/extensions/spe.h
+++ b/include/lib/extensions/spe.h
@@ -4,11 +4,13 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __SPE_H__
-#define __SPE_H__
+#ifndef SPE_H
+#define SPE_H
 
-int spe_supported(void);
-void spe_enable(int el2_unused);
+#include <stdbool.h>
+
+bool spe_supported(void);
+void spe_enable(bool el2_unused);
 void spe_disable(void);
 
-#endif /* __SPE_H__ */
+#endif /* SPE_H */
diff --git a/include/lib/extensions/sve.h b/include/lib/extensions/sve.h
index 9c7f37f..83df177 100644
--- a/include/lib/extensions/sve.h
+++ b/include/lib/extensions/sve.h
@@ -4,10 +4,12 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
-#ifndef __SVE_H__
-#define __SVE_H__
+#ifndef SVE_H
+#define SVE_H
 
-int sve_supported(void);
-void sve_enable(int el2_unused);
+#include <stdbool.h>
+
+bool sve_supported(void);
+void sve_enable(bool el2_unused);
 
-#endif /* __SVE_H__ */
+#endif /* SVE_H */