feat(RME): Makefile changes to support ENABLE_RME build option

This patch updates the build system to support the ENABLE_RME
build flag option.
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I7a145a2812fdf812e5b6353a35412c3bffe84fba

Makefile

 #
-# Copyright (c) 2013-2021, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2021, Arm Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -129,6 +129,19 @@ else
         $(error Unknown BRANCH_PROTECTION value ${BRANCH_PROTECTION})
 endif
 
+# RME requires AARCH64 and other features
+ifneq (${ENABLE_RME},0)
+ifneq (${ARCH},aarch64)
+       $(error ENABLE_RME requires AArch64)
+endif
+# RME requires el2 context to be saved for now.
+CTX_INCLUDE_EL2_REGS := 1
+SPD = rmmd
+# These arch versions will need to be updated later.
+ARM_ARCH_MAJOR := 8
+ARM_ARCH_MINOR := 4
+endif
+
 # USE_SPINLOCK_CAS requires AArch64 build
 ifeq (${USE_SPINLOCK_CAS},1)
 ifneq (${ARCH},aarch64)
@@ -521,6 +534,14 @@ ifneq (${SPD},none)
         ifeq ($(findstring optee_sp,$(ARM_SPMC_MANIFEST_DTS)),optee_sp)
             DTC_CPPFLAGS	+=	-DOPTEE_SP_FW_CONFIG
         endif
+    else ifeq (${SPD},rmmd)
+        $(warning "RMMD is an experimental feature")
+        # RMMD is located in std_svc directory
+        SPD_DIR := std_svc
+
+        ifeq ($(CTX_INCLUDE_EL2_REGS),0)
+                $(error RMM at S-EL2 requires CTX_INCLUDE_EL2_REGS option)
+        endif
     else
         # All other SPDs in spd directory
         SPD_DIR := spd
@@ -906,6 +927,7 @@ $(eval $(call assert_booleans,\
         ENABLE_PIE \
         ENABLE_PMF \
         ENABLE_PSCI_STAT \
+        ENABLE_RME \
         ENABLE_RUNTIME_INSTRUMENTATION \
         ENABLE_SPE_FOR_LOWER_ELS \
         ENABLE_SVE_FOR_NS \
@@ -999,6 +1021,7 @@ $(eval $(call add_defines,\
         ENABLE_PIE \
         ENABLE_PMF \
         ENABLE_PSCI_STAT \
+        ENABLE_RME \
         ENABLE_RUNTIME_INSTRUMENTATION \
         ENABLE_SPE_FOR_LOWER_ELS \
         ENABLE_SVE_FOR_NS \

docs/getting_started/build-options.rst

@@ -264,6 +264,9 @@ Common build options
    be enabled. If ``ENABLE_PMF`` is set, the residency statistics are tracked in
    software.
 
+- ``ENABLE_RME``: Boolean option to enable support for the ARMv9 Realm
+   Management Extension.
+
 -  ``ENABLE_RUNTIME_INSTRUMENTATION``: Boolean option to enable runtime
    instrumentation which injects timestamp collection points into TF-A to
    allow runtime performance to be measured. Currently, only PSCI is

make_helpers/defaults.mk

 #
-# Copyright (c) 2016-2021, ARM Limited. All rights reserved.
+# Copyright (c) 2016-2021, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -102,6 +102,9 @@ ENABLE_PMF			:= 0
 # Flag to enable PSCI STATs functionality
 ENABLE_PSCI_STAT		:= 0
 
+# Flag to enable Realm Management Extension (RME)
+ENABLE_RME			:= 0
+
 # Flag to enable runtime instrumentation using PMF
 ENABLE_RUNTIME_INSTRUMENTATION	:= 0