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/include/common/test_helpers.h b/include/common/test_helpers.h
index 8cddc72..ced1745 100644
--- a/include/common/test_helpers.h
+++ b/include/common/test_helpers.h
@@ -115,6 +115,16 @@
 		}								\
 	} while (0)
 
+#define SKIP_TEST_IF_DEBUGV8P9_NOT_SUPPORTED()					\
+	do {									\
+		if (arch_get_debug_version() != 				\
+				ID_AA64DFR0_V8_9_DEBUG_ARCH_SUPPORTED) {	\
+			tftf_testcase_printf(					\
+				"Debugv8p9 not supported\n");			\
+			return TEST_RESULT_SKIPPED;				\
+		}								\
+	} while (0)
+
 #define SKIP_TEST_IF_SVE_NOT_SUPPORTED()					\
 	do {									\
 		if (!is_armv8_2_sve_present()) {				\
diff --git a/include/lib/aarch64/arch.h b/include/lib/aarch64/arch.h
index 6a0d286..a57b8de 100644
--- a/include/lib/aarch64/arch.h
+++ b/include/lib/aarch64/arch.h
@@ -194,6 +194,7 @@
 #define ID_AA64DFR0_V8_DEBUG_ARCH_VHE_SUPPORTED	U(7)
 #define ID_AA64DFR0_V8_2_DEBUG_ARCH_SUPPORTED	U(8)
 #define ID_AA64DFR0_V8_4_DEBUG_ARCH_SUPPORTED	U(9)
+#define ID_AA64DFR0_V8_9_DEBUG_ARCH_SUPPORTED   U(0xb)
 
 /* ID_AA64DFR0_EL1.HPMN0 definitions */
 #define ID_AA64DFR0_HPMN0_SHIFT			U(60)
@@ -1289,6 +1290,11 @@
  ******************************************************************************/
 #define CNTPOFF_EL2  S3_4_C14_C0_6
 
+/******************************************************************************
+ * Armv8.9 - Breakpoint and Watchpoint Selection Register
+ ******************************************************************************/
+#define MDSELR_EL1		S2_0_C0_C4_2
+
 /*******************************************************************************
  * Armv9.0 - Trace Buffer Extension System Registers
  ******************************************************************************/
diff --git a/include/lib/aarch64/arch_helpers.h b/include/lib/aarch64/arch_helpers.h
index 4b9c33e..a91625c 100644
--- a/include/lib/aarch64/arch_helpers.h
+++ b/include/lib/aarch64/arch_helpers.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2024, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -611,6 +611,8 @@
 DEFINE_RENAME_SYSREG_RW_FUNCS(trcclaimclr, TRCCLAIMCLR)
 DEFINE_RENAME_SYSREG_READ_FUNC(trcdevarch, TRCDEVARCH)
 
+DEFINE_RENAME_SYSREG_READ_FUNC(mdselr_el1, MDSELR_EL1)
+
 /* FEAT_HCX HCRX_EL2 */
 DEFINE_RENAME_SYSREG_RW_FUNCS(hcrx_el2, HCRX_EL2)
 
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" />