feat(debugv8p9): add support for FEAT_Debugv8p9

This patch enables FEAT_Debugv8p9 and prevents EL1/0 from
trapping to EL3 when accessing MDSELR_EL1 register by
setting the MDCR_EL3.EBWE bit.

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I3613af1dd8cb8c0d3c33dc959f170846c0b9695a
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 577d6ba..1e40fb3 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -24,6 +24,7 @@
 #include <lib/el3_runtime/pubsub_events.h>
 #include <lib/extensions/amu.h>
 #include <lib/extensions/brbe.h>
+#include <lib/extensions/debug_v8p9.h>
 #include <lib/extensions/mpam.h>
 #include <lib/extensions/pmuv3.h>
 #include <lib/extensions/sme.h>
@@ -772,6 +773,10 @@
 		sme_enable(ctx);
 	}
 
+	if (is_feat_debugv8p9_supported()) {
+		debugv8p9_extended_bp_wp_enable(ctx);
+	}
+
 	pmuv3_enable(ctx);
 #endif /* IMAGE_BL31 */
 }