diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index 9ef9c26..3383a3b 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -170,6 +170,7 @@
 #define ID_AA64PFR0_GIC_MASK	ULL(0xf)
 #define ID_AA64PFR0_SVE_SHIFT	U(32)
 #define ID_AA64PFR0_SVE_MASK	ULL(0xf)
+#define ID_AA64PFR0_SVE_LENGTH	U(4)
 #define ID_AA64PFR0_SEL2_SHIFT	U(36)
 #define ID_AA64PFR0_SEL2_MASK	ULL(0xf)
 #define ID_AA64PFR0_MPAM_SHIFT	U(40)
@@ -529,7 +530,7 @@
 #define TTA_BIT			(U(1) << 20)
 #define TFP_BIT			(U(1) << 10)
 #define CPTR_EZ_BIT		(U(1) << 8)
-#define CPTR_EL3_RESET_VAL	U(0x0)
+#define CPTR_EL3_RESET_VAL	(TCPAC_BIT | TAM_BIT | TTA_BIT | TFP_BIT & ~(CPTR_EZ_BIT))
 
 /* CPTR_EL2 definitions */
 #define CPTR_EL2_RES1		((U(1) << 13) | (U(1) << 12) | (U(0x3ff)))
diff --git a/include/arch/aarch64/el3_common_macros.S b/include/arch/aarch64/el3_common_macros.S
index b610b37..9734335 100644
--- a/include/arch/aarch64/el3_common_macros.S
+++ b/include/arch/aarch64/el3_common_macros.S
@@ -185,7 +185,14 @@
 	 * CPTR_EL3.TFP: Set to zero so that accesses to the V- or Z- registers
 	 *  by Advanced SIMD, floating-point or SVE instructions (if implemented)
 	 *  do not trap to EL3.
+	 *
+	 * CPTR_EL3.TAM: Set to one so that Activity Monitor access is
+	 *  trapped to EL3 by default.
+	 *
+	 * CPTR_EL3.EZ: Set to zero so that all SVE functionality is trapped
+	 *  to EL3 by default.
 	 */
+
 	mov_imm x0, (CPTR_EL3_RESET_VAL & ~(TCPAC_BIT | TTA_BIT | TFP_BIT))
 	msr	cptr_el3, x0