diff --git a/include/lib/cpus/aarch64/cpuamu.h b/include/lib/cpus/aarch64/cpuamu.h
index 960a52484..921abdbd4 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 @@ void cpuamu_context_restore(unsigned int nr_counters);
 
 #endif /* __ASSEMBLY__ */
 
-#endif /* __CPUAMU_H__ */
+#endif /* CPUAMU_H */
diff --git a/include/lib/extensions/amu.h b/include/lib/extensions/amu.h
index 46d5e1593..1836fe5ae 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 @@ uint64_t amu_group1_cnt_read(int idx);
 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 0c660bb83..ab4e6aaba 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 571b96b65..ac8c00a43 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 b2b188ef5..d4b925fe4 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 9c7f37f26..83df1775e 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>
 
-#endif /* __SVE_H__ */
+bool sve_supported(void);
+void sve_enable(bool el2_unused);
+
+#endif /* SVE_H */
diff --git a/lib/cpus/aarch64/cpuamu_helpers.S b/lib/cpus/aarch64/cpuamu_helpers.S
index 8965d6d09..79b72883b 100644
--- a/lib/cpus/aarch64/cpuamu_helpers.S
+++ b/lib/cpus/aarch64/cpuamu_helpers.S
@@ -16,7 +16,7 @@
 	.globl	cpuamu_write_cpuamcntenclr_el0
 
 /*
- * uint64_t cpuamu_cnt_read(int idx);
+ * uint64_t cpuamu_cnt_read(unsigned int idx);
  *
  * Given `idx`, read the corresponding AMU counter
  * and return it in `x0`.
@@ -41,7 +41,7 @@ func cpuamu_cnt_read
 endfunc cpuamu_cnt_read
 
 /*
- * void cpuamu_cnt_write(int idx, uint64_t val);
+ * void cpuamu_cnt_write(unsigned int idx, uint64_t val);
  *
  * Given `idx`, write `val` to the corresponding AMU counter.
  */
diff --git a/lib/el3_runtime/aarch32/context_mgmt.c b/lib/el3_runtime/aarch32/context_mgmt.c
index 11ef6e5f4..80cea2847 100644
--- a/lib/el3_runtime/aarch32/context_mgmt.c
+++ b/lib/el3_runtime/aarch32/context_mgmt.c
@@ -14,6 +14,7 @@
 #include <platform.h>
 #include <platform_def.h>
 #include <smccc_helpers.h>
+#include <stdbool.h>
 #include <string.h>
 #include <utils.h>
 
@@ -129,7 +130,7 @@ void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
  * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
  * it is zero.
  ******************************************************************************/
-static void enable_extensions_nonsecure(int el2_unused)
+static void enable_extensions_nonsecure(bool el2_unused)
 {
 #if IMAGE_BL32
 #if ENABLE_AMU
@@ -175,7 +176,7 @@ void cm_prepare_el3_exit(uint32_t security_state)
 {
 	uint32_t hsctlr, scr;
 	cpu_context_t *ctx = cm_get_context(security_state);
-	int el2_unused = 0;
+	bool el2_unused = false;
 
 	assert(ctx);
 
@@ -200,7 +201,7 @@ void cm_prepare_el3_exit(uint32_t security_state)
 			isb();
 		} else if (read_id_pfr1() &
 			(ID_PFR1_VIRTEXT_MASK << ID_PFR1_VIRTEXT_SHIFT)) {
-			el2_unused = 1;
+			el2_unused = true;
 
 			/*
 			 * Set the NS bit to access NS copies of certain banked
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index d3984a289..f037e18a4 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -18,6 +18,7 @@
 #include <pubsub_events.h>
 #include <smccc_helpers.h>
 #include <spe.h>
+#include <stdbool.h>
 #include <string.h>
 #include <sve.h>
 #include <utils.h>
@@ -231,7 +232,7 @@ void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
  * When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
  * it is zero.
  ******************************************************************************/
-static void enable_extensions_nonsecure(int el2_unused)
+static void enable_extensions_nonsecure(bool el2_unused)
 {
 #if IMAGE_BL31
 #if ENABLE_SPE_FOR_LOWER_ELS
@@ -289,7 +290,7 @@ void cm_prepare_el3_exit(uint32_t security_state)
 {
 	uint32_t sctlr_elx, scr_el3, mdcr_el2;
 	cpu_context_t *ctx = cm_get_context(security_state);
-	int el2_unused = 0;
+	bool el2_unused = false;
 	uint64_t hcr_el2 = 0;
 
 	assert(ctx);
@@ -304,7 +305,7 @@ void cm_prepare_el3_exit(uint32_t security_state)
 			sctlr_elx |= SCTLR_EL2_RES1;
 			write_sctlr_el2(sctlr_elx);
 		} else if (EL_IMPLEMENTED(2)) {
-			el2_unused = 1;
+			el2_unused = true;
 
 			/*
 			 * EL2 present but unused, need to disable safely.
diff --git a/lib/extensions/amu/aarch32/amu.c b/lib/extensions/amu/aarch32/amu.c
index 05c98f1cd..585d908f7 100644
--- a/lib/extensions/amu/aarch32/amu.c
+++ b/lib/extensions/amu/aarch32/amu.c
@@ -10,6 +10,7 @@
 #include <arch_helpers.h>
 #include <platform.h>
 #include <pubsub_events.h>
+#include <stdbool.h>
 
 #define AMU_GROUP0_NR_COUNTERS	4
 
@@ -20,17 +21,17 @@ struct amu_ctx {
 
 static struct amu_ctx amu_ctxs[PLATFORM_CORE_COUNT];
 
-int amu_supported(void)
+bool amu_supported(void)
 {
 	uint64_t features;
 
 	features = read_id_pfr0() >> ID_PFR0_AMU_SHIFT;
-	return (features & ID_PFR0_AMU_MASK) == 1;
+	return (features & ID_PFR0_AMU_MASK) == 1U;
 }
 
-void amu_enable(int el2_unused)
+void amu_enable(bool el2_unused)
 {
-	if (amu_supported() == 0)
+	if (!amu_supported())
 		return;
 
 	if (el2_unused) {
@@ -54,8 +55,8 @@ void amu_enable(int el2_unused)
 /* Read the group 0 counter identified by the given `idx`. */
 uint64_t amu_group0_cnt_read(int idx)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP0_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP0_NR_COUNTERS));
 
 	return amu_group0_cnt_read_internal(idx);
 }
@@ -63,8 +64,8 @@ uint64_t amu_group0_cnt_read(int idx)
 /* Write the group 0 counter identified by the given `idx` with `val`. */
 void amu_group0_cnt_write(int idx, uint64_t val)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP0_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP0_NR_COUNTERS));
 
 	amu_group0_cnt_write_internal(idx, val);
 	isb();
@@ -73,8 +74,8 @@ void amu_group0_cnt_write(int idx, uint64_t val)
 /* Read the group 1 counter identified by the given `idx`. */
 uint64_t amu_group1_cnt_read(int idx)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP1_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP1_NR_COUNTERS));
 
 	return amu_group1_cnt_read_internal(idx);
 }
@@ -82,8 +83,8 @@ uint64_t amu_group1_cnt_read(int idx)
 /* Write the group 1 counter identified by the given `idx` with `val`. */
 void amu_group1_cnt_write(int idx, uint64_t val)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP1_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP1_NR_COUNTERS));
 
 	amu_group1_cnt_write_internal(idx, val);
 	isb();
@@ -91,8 +92,8 @@ void amu_group1_cnt_write(int idx, uint64_t val)
 
 void amu_group1_set_evtype(int idx, unsigned int val)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP1_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP1_NR_COUNTERS));
 
 	amu_group1_set_evtype_internal(idx, val);
 	isb();
@@ -103,7 +104,7 @@ static void *amu_context_save(const void *arg)
 	struct amu_ctx *ctx;
 	int i;
 
-	if (amu_supported() == 0)
+	if (!amu_supported())
 		return (void *)-1;
 
 	ctx = &amu_ctxs[plat_my_core_pos()];
@@ -126,7 +127,7 @@ static void *amu_context_save(const void *arg)
 	for (i = 0; i < AMU_GROUP1_NR_COUNTERS; i++)
 		ctx->group1_cnts[i] = amu_group1_cnt_read(i);
 
-	return 0;
+	return (void *)0;
 }
 
 static void *amu_context_restore(const void *arg)
@@ -134,13 +135,13 @@ static void *amu_context_restore(const void *arg)
 	struct amu_ctx *ctx;
 	int i;
 
-	if (amu_supported() == 0)
+	if (!amu_supported())
 		return (void *)-1;
 
 	ctx = &amu_ctxs[plat_my_core_pos()];
 
 	/* Counters were disabled in `amu_context_save()` */
-	assert(read_amcntenset0() == 0 && read_amcntenset1() == 0);
+	assert((read_amcntenset0() == 0U) && (read_amcntenset1() == 0U));
 
 	/* Restore group 0 counters */
 	for (i = 0; i < AMU_GROUP0_NR_COUNTERS; i++)
@@ -153,7 +154,7 @@ static void *amu_context_restore(const void *arg)
 
 	/* Enable group 1 counters */
 	write_amcntenset1(AMU_GROUP1_COUNTERS_MASK);
-	return 0;
+	return (void *)0;
 }
 
 SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_start, amu_context_save);
diff --git a/lib/extensions/amu/aarch64/amu.c b/lib/extensions/amu/aarch64/amu.c
index 5d556e5d3..1564e8402 100644
--- a/lib/extensions/amu/aarch64/amu.c
+++ b/lib/extensions/amu/aarch64/amu.c
@@ -11,6 +11,7 @@
 #include <assert.h>
 #include <platform.h>
 #include <pubsub_events.h>
+#include <stdbool.h>
 
 #define AMU_GROUP0_NR_COUNTERS	4
 
@@ -21,23 +22,23 @@ struct amu_ctx {
 
 static struct amu_ctx amu_ctxs[PLATFORM_CORE_COUNT];
 
-int amu_supported(void)
+bool amu_supported(void)
 {
 	uint64_t features;
 
 	features = read_id_aa64pfr0_el1() >> ID_AA64PFR0_AMU_SHIFT;
-	return (features & ID_AA64PFR0_AMU_MASK) == 1;
+	return (features & ID_AA64PFR0_AMU_MASK) == 1U;
 }
 
 /*
  * Enable counters.  This function is meant to be invoked
  * by the context management library before exiting from EL3.
  */
-void amu_enable(int el2_unused)
+void amu_enable(bool el2_unused)
 {
 	uint64_t v;
 
-	if (amu_supported() == 0)
+	if (!amu_supported())
 		return;
 
 	if (el2_unused) {
@@ -67,8 +68,8 @@ void amu_enable(int el2_unused)
 /* Read the group 0 counter identified by the given `idx`. */
 uint64_t amu_group0_cnt_read(int idx)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP0_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP0_NR_COUNTERS));
 
 	return amu_group0_cnt_read_internal(idx);
 }
@@ -76,8 +77,8 @@ uint64_t amu_group0_cnt_read(int idx)
 /* Write the group 0 counter identified by the given `idx` with `val`. */
 void amu_group0_cnt_write(int idx, uint64_t val)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP0_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP0_NR_COUNTERS));
 
 	amu_group0_cnt_write_internal(idx, val);
 	isb();
@@ -86,8 +87,8 @@ void amu_group0_cnt_write(int idx, uint64_t val)
 /* Read the group 1 counter identified by the given `idx`. */
 uint64_t amu_group1_cnt_read(int idx)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP1_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP1_NR_COUNTERS));
 
 	return amu_group1_cnt_read_internal(idx);
 }
@@ -95,8 +96,8 @@ uint64_t amu_group1_cnt_read(int idx)
 /* Write the group 1 counter identified by the given `idx` with `val`. */
 void amu_group1_cnt_write(int idx, uint64_t val)
 {
-	assert(amu_supported() != 0);
-	assert(idx >= 0 && idx < AMU_GROUP1_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP1_NR_COUNTERS));
 
 	amu_group1_cnt_write_internal(idx, val);
 	isb();
@@ -108,8 +109,8 @@ void amu_group1_cnt_write(int idx, uint64_t val)
  */
 void amu_group1_set_evtype(int idx, unsigned int val)
 {
-	assert(amu_supported() != 0);
-	assert (idx >= 0 && idx < AMU_GROUP1_NR_COUNTERS);
+	assert(amu_supported());
+	assert((idx >= 0) && (idx < AMU_GROUP1_NR_COUNTERS));
 
 	amu_group1_set_evtype_internal(idx, val);
 	isb();
@@ -120,14 +121,14 @@ static void *amu_context_save(const void *arg)
 	struct amu_ctx *ctx = &amu_ctxs[plat_my_core_pos()];
 	int i;
 
-	if (amu_supported() == 0)
+	if (!amu_supported())
 		return (void *)-1;
 
 	/* Assert that group 0/1 counter configuration is what we expect */
-	assert(read_amcntenset0_el0() == AMU_GROUP0_COUNTERS_MASK &&
-	       read_amcntenset1_el0() == AMU_GROUP1_COUNTERS_MASK);
+	assert((read_amcntenset0_el0() == AMU_GROUP0_COUNTERS_MASK) &&
+	       (read_amcntenset1_el0() == AMU_GROUP1_COUNTERS_MASK));
 
-	assert((sizeof(int) * 8) - __builtin_clz(AMU_GROUP1_COUNTERS_MASK)
+	assert(((sizeof(int) * 8) - __builtin_clz(AMU_GROUP1_COUNTERS_MASK))
 		<= AMU_GROUP1_NR_COUNTERS);
 
 	/*
@@ -146,7 +147,7 @@ static void *amu_context_save(const void *arg)
 	for (i = 0; i < AMU_GROUP1_NR_COUNTERS; i++)
 		ctx->group1_cnts[i] = amu_group1_cnt_read(i);
 
-	return 0;
+	return (void *)0;
 }
 
 static void *amu_context_restore(const void *arg)
@@ -154,30 +155,30 @@ static void *amu_context_restore(const void *arg)
 	struct amu_ctx *ctx = &amu_ctxs[plat_my_core_pos()];
 	int i;
 
-	if (amu_supported() == 0)
+	if (!amu_supported())
 		return (void *)-1;
 
 	/* Counters were disabled in `amu_context_save()` */
-	assert(read_amcntenset0_el0() == 0 && read_amcntenset1_el0() == 0);
+	assert((read_amcntenset0_el0() == 0U) && (read_amcntenset1_el0() == 0U));
 
-	assert((sizeof(int) * 8) - __builtin_clz(AMU_GROUP1_COUNTERS_MASK)
+	assert(((sizeof(int) * 8U) - __builtin_clz(AMU_GROUP1_COUNTERS_MASK))
 		<= AMU_GROUP1_NR_COUNTERS);
 
 	/* Restore group 0 counters */
 	for (i = 0; i < AMU_GROUP0_NR_COUNTERS; i++)
-		if (AMU_GROUP0_COUNTERS_MASK & (1U << i))
+		if ((AMU_GROUP0_COUNTERS_MASK & (1U << i)) != 0U)
 			amu_group0_cnt_write(i, ctx->group0_cnts[i]);
 
 	/* Restore group 1 counters */
 	for (i = 0; i < AMU_GROUP1_NR_COUNTERS; i++)
-		if (AMU_GROUP1_COUNTERS_MASK & (1U << i))
+		if ((AMU_GROUP1_COUNTERS_MASK & (1U << i)) != 0U)
 			amu_group1_cnt_write(i, ctx->group1_cnts[i]);
 
 	/* Restore group 0/1 counter configuration */
 	write_amcntenset0_el0(AMU_GROUP0_COUNTERS_MASK);
 	write_amcntenset1_el0(AMU_GROUP1_COUNTERS_MASK);
 
-	return 0;
+	return (void *)0;
 }
 
 SUBSCRIBE_TO_EVENT(psci_suspend_pwrdown_start, amu_context_save);
diff --git a/lib/extensions/mpam/mpam.c b/lib/extensions/mpam/mpam.c
index e628827bf..d57bb470b 100644
--- a/lib/extensions/mpam/mpam.c
+++ b/lib/extensions/mpam/mpam.c
@@ -16,7 +16,7 @@ bool mpam_supported(void)
 	return ((features & ID_AA64PFR0_MPAM_MASK) != 0U);
 }
 
-void mpam_enable(int el2_unused)
+void mpam_enable(bool el2_unused)
 {
 	if (!mpam_supported())
 		return;
@@ -31,7 +31,7 @@ void mpam_enable(int el2_unused)
 	 * If EL2 is implemented but unused, disable trapping to EL2 when lower
 	 * ELs access their own MPAM registers.
 	 */
-	if (el2_unused != 0) {
+	if (el2_unused) {
 		write_mpam2_el2(0);
 
 		if ((read_mpamidr_el1() & MPAMIDR_HAS_HCR_BIT) != 0U)
diff --git a/lib/extensions/spe/spe.c b/lib/extensions/spe/spe.c
index dc3584037..e5df015b0 100644
--- a/lib/extensions/spe/spe.c
+++ b/lib/extensions/spe/spe.c
@@ -8,26 +8,30 @@
 #include <arch_helpers.h>
 #include <pubsub.h>
 #include <spe.h>
+#include <stdbool.h>
 
-/*
- * The assembler does not yet understand the psb csync mnemonic
- * so use the equivalent hint instruction.
- */
-#define psb_csync()	asm volatile("hint #17")
+static inline void psb_csync(void)
+{
+	/*
+	 * The assembler does not yet understand the psb csync mnemonic
+	 * so use the equivalent hint instruction.
+	 */
+	__asm__ volatile("hint #17");
+}
 
-int spe_supported(void)
+bool spe_supported(void)
 {
 	uint64_t features;
 
 	features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_PMS_SHIFT;
-	return (features & ID_AA64DFR0_PMS_MASK) == 1;
+	return (features & ID_AA64DFR0_PMS_MASK) == 1U;
 }
 
-void spe_enable(int el2_unused)
+void spe_enable(bool el2_unused)
 {
 	uint64_t v;
 
-	if (spe_supported() == 0)
+	if (!spe_supported())
 		return;
 
 	if (el2_unused) {
@@ -59,7 +63,7 @@ void spe_disable(void)
 {
 	uint64_t v;
 
-	if (spe_supported() == 0)
+	if (!spe_supported())
 		return;
 
 	/* Drain buffered data */
@@ -75,13 +79,14 @@ void spe_disable(void)
 
 static void *spe_drain_buffers_hook(const void *arg)
 {
-	if (spe_supported() == 0)
+	if (!spe_supported())
 		return (void *)-1;
 
 	/* Drain buffered data */
 	psb_csync();
 	dsbnsh();
-	return 0;
+
+	return (void *)0;
 }
 
 SUBSCRIBE_TO_EVENT(cm_entering_secure_world, spe_drain_buffers_hook);
diff --git a/lib/extensions/sve/sve.c b/lib/extensions/sve/sve.c
index 644248780..e031bf61b 100644
--- a/lib/extensions/sve/sve.c
+++ b/lib/extensions/sve/sve.c
@@ -7,21 +7,22 @@
 #include <arch.h>
 #include <arch_helpers.h>
 #include <pubsub.h>
+#include <stdbool.h>
 #include <sve.h>
 
-int sve_supported(void)
+bool sve_supported(void)
 {
 	uint64_t features;
 
 	features = read_id_aa64pfr0_el1() >> ID_AA64PFR0_SVE_SHIFT;
-	return (features & ID_AA64PFR0_SVE_MASK) == 1;
+	return (features & ID_AA64PFR0_SVE_MASK) == 1U;
 }
 
 static void *disable_sve_hook(const void *arg)
 {
 	uint64_t cptr;
 
-	if (sve_supported() == 0)
+	if (!sve_supported())
 		return (void *)-1;
 
 	/*
@@ -39,14 +40,14 @@ static void *disable_sve_hook(const void *arg)
 	 * No explicit ISB required here as ERET to switch to Secure
 	 * world covers it
 	 */
-	return 0;
+	return (void *)0;
 }
 
 static void *enable_sve_hook(const void *arg)
 {
 	uint64_t cptr;
 
-	if (sve_supported() == 0)
+	if (!sve_supported())
 		return (void *)-1;
 
 	/*
@@ -60,14 +61,14 @@ static void *enable_sve_hook(const void *arg)
 	 * No explicit ISB required here as ERET to switch to Non-secure
 	 * world covers it
 	 */
-	return 0;
+	return (void *)0;
 }
 
-void sve_enable(int el2_unused)
+void sve_enable(bool el2_unused)
 {
 	uint64_t cptr;
 
-	if (sve_supported() == 0)
+	if (!sve_supported())
 		return;
 
 #if CTX_INCLUDE_FPREGS