feat(sys_reg_trace): enable trace system registers access from lower NS ELs

Introduced a build flag 'ENABLE_SYS_REG_TRACE_FOR_NS' to enable trace
system registers access in NS-EL2, or NS-EL1 (when NS-EL2 is
implemented but unused).

Change-Id: Idc1acede4186e101758cbf7bed5af7b634d7d18d
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/include/arch/aarch32/arch_helpers.h b/include/arch/aarch32/arch_helpers.h
index 726baf5..8d628c1 100644
--- a/include/arch/aarch32/arch_helpers.h
+++ b/include/arch/aarch32/arch_helpers.h
@@ -217,6 +217,7 @@
 DEFINE_COPROCR_READ_FUNC(mpidr, MPIDR)
 DEFINE_COPROCR_READ_FUNC(midr, MIDR)
 DEFINE_COPROCR_READ_FUNC(id_mmfr4, ID_MMFR4)
+DEFINE_COPROCR_READ_FUNC(id_dfr0, ID_DFR0)
 DEFINE_COPROCR_READ_FUNC(id_pfr0, ID_PFR0)
 DEFINE_COPROCR_READ_FUNC(id_pfr1, ID_PFR1)
 DEFINE_COPROCR_READ_FUNC(isr, ISR)
diff --git a/include/lib/extensions/sys_reg_trace.h b/include/lib/extensions/sys_reg_trace.h
new file mode 100644
index 0000000..74470fe
--- /dev/null
+++ b/include/lib/extensions/sys_reg_trace.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2021, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SYS_REG_TRACE_H
+#define SYS_REG_TRACE_H
+
+#include <context.h>
+
+#if __aarch64__
+void sys_reg_trace_enable(cpu_context_t *context);
+#else
+void sys_reg_trace_enable(void);
+#endif /* __aarch64__ */
+
+#endif /* SYS_REG_TRACE_H */