feat(debugv8p9): test if EL3 has properly enabled FEAT_Debugv8p9

When FEAT_Debugv8p9 is not enabled, access to MDSELR_EL1
traps to EL3. Access to FEAT_DEBUGV8P9 control registers
must be explicitly enabled in EL3,

This testcase uses this behavior to test if
FEAT_Debugv8p9 is enabled or not.

Change-Id: I2f9a0158e9f38eaffac2e27c40d44d3c520d508d
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
diff --git a/tftf/tests/extensions/debugv8p9/test_debugv8p9.c b/tftf/tests/extensions/debugv8p9/test_debugv8p9.c
new file mode 100644
index 0000000..033aedb
--- /dev/null
+++ b/tftf/tests/extensions/debugv8p9/test_debugv8p9.c
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2024, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <test_helpers.h>
+#include <tftf_lib.h>
+#include <debug.h>
+#include <arch_helpers.h>
+
+test_result_t test_debugv8p9_enabled(void)
+{
+	SKIP_TEST_IF_AARCH32();
+
+#if __aarch64__
+	SKIP_TEST_IF_DEBUGV8P9_NOT_SUPPORTED();
+
+	read_mdselr_el1();
+#endif
+	return TEST_RESULT_SUCCESS;
+}
diff --git a/tftf/tests/tests-cpu-extensions.mk b/tftf/tests/tests-cpu-extensions.mk
index b0af1a3..51f2e55 100644
--- a/tftf/tests/tests-cpu-extensions.mk
+++ b/tftf/tests/tests-cpu-extensions.mk
@@ -8,6 +8,7 @@
 	extensions/afp/test_afp.c					\
 	extensions/amu/test_amu.c					\
 	extensions/brbe/test_brbe.c					\
+	extensions/debugv8p9/test_debugv8p9.c				\
 	extensions/ecv/test_ecv.c					\
 	extensions/fgt/test_fgt.c					\
 	extensions/pmuv3/test_pmuv3.c					\
diff --git a/tftf/tests/tests-cpu-extensions.xml b/tftf/tests/tests-cpu-extensions.xml
index 3b93344..0f8d0f6 100644
--- a/tftf/tests/tests-cpu-extensions.xml
+++ b/tftf/tests/tests-cpu-extensions.xml
@@ -12,6 +12,7 @@
     <testcase name="AMUv1 valid counter values" function="test_amu_valid_ctr" />
     <testcase name="AMUv1 suspend/resume" function="test_amu_suspend_resume" />
     <testcase name="SVE support" function="test_sve_support" />
+    <testcase name="Debugv8p9 support" function="test_debugv8p9_enabled" />
     <testcase name="Access Pointer Authentication Registers" function="test_pauth_reg_access" />
     <testcase name="Use Pointer Authentication Instructions" function="test_pauth_instructions" />
     <testcase name="Check for Pointer Authentication key leakage from EL3" function="test_pauth_leakage" />