diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index c12dbc4..d71ec00 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -442,6 +442,9 @@
 #define MDCR_EnPMSN_BIT		(ULL(1) << 36)
 #define MDCR_MPMX_BIT		(ULL(1) << 35)
 #define MDCR_MCCD_BIT		(ULL(1) << 34)
+#define MDCR_NSTB(x)		((x) << 24)
+#define MDCR_NSTB_EL1		ULL(0x3)
+#define MDCR_NSTBE		(ULL(1) << 26)
 #define MDCR_MTPME_BIT		(ULL(1) << 28)
 #define MDCR_TDCC_BIT		(ULL(1) << 27)
 #define MDCR_SCCD_BIT		(ULL(1) << 23)
@@ -465,6 +468,8 @@
 /* MDCR_EL2 definitions */
 #define MDCR_EL2_MTPME		(U(1) << 28)
 #define MDCR_EL2_HLP		(U(1) << 26)
+#define MDCR_EL2_E2TB(x)	((x) << 24)
+#define MDCR_EL2_E2TB_EL1	U(0x3)
 #define MDCR_EL2_HCCD		(U(1) << 23)
 #define MDCR_EL2_TTRF		(U(1) << 19)
 #define MDCR_EL2_HPMD		(U(1) << 17)
diff --git a/include/arch/aarch64/el3_common_macros.S b/include/arch/aarch64/el3_common_macros.S
index 9734335..2aa2222 100644
--- a/include/arch/aarch64/el3_common_macros.S
+++ b/include/arch/aarch64/el3_common_macros.S
@@ -126,12 +126,19 @@
 	 *  Debug is not implemented this bit does not have any effect on the
 	 *  counters unless there is support for the implementation defined
 	 *  authentication interface ExternalSecureNoninvasiveDebugEnabled().
+	 *
+	 * MDCR_EL3.NSTB, MDCR_EL3.NSTBE: Set to zero so that Trace Buffer
+	 *  owning security state is Secure state. If FEAT_TRBE is implemented,
+	 *  accesses to Trace Buffer control registers at EL2 and EL1 in any
+	 *  security state generates trap exceptions to EL3.
+	 *  If FEAT_TRBE is not implemented, these bits are RES0.
 	 * ---------------------------------------------------------------------
 	 */
 	mov_imm	x0, ((MDCR_EL3_RESET_VAL | MDCR_SDD_BIT | \
 		      MDCR_SPD32(MDCR_SPD32_DISABLE) | MDCR_SCCD_BIT | \
 		      MDCR_MCCD_BIT) & ~(MDCR_SPME_BIT | MDCR_TDOSA_BIT | \
-		      MDCR_TDA_BIT | MDCR_TPM_BIT))
+		      MDCR_TDA_BIT | MDCR_TPM_BIT | MDCR_NSTB(MDCR_NSTB_EL1) | \
+		      MDCR_NSTBE))
 
 	msr	mdcr_el3, x0