Added a new arm64-specific empty subsystem amongst TARGETS of KSFT build
framework; once populated with testcases, it will be possible to build
and invoke the new KSFT TARGETS=arm64 related tests from the toplevel
Makefile in the usual ways.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
 tools/testing/selftests/Makefile       |  1 +
 tools/testing/selftests/arm64/Makefile | 51 ++++++++++++++++++++++++++
 tools/testing/selftests/arm64/README   | 44 ++++++++++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/Makefile
 create mode 100644 tools/testing/selftests/arm64/README

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 9781ca79794a..4ff0b41ead8a 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 TARGETS = android
+TARGETS += arm64
 TARGETS += bpf
 TARGETS += breakpoints
 TARGETS += capabilities

diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
new file mode 100644
index 000000000000..03a0d4f71218
--- /dev/null
+++ b/tools/testing/selftests/arm64/Makefile

@@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2019 ARM Limited
+
+# When ARCH not overridden for crosscompiling, lookup machine
+ARCH ?= $(shell uname -m)
+ARCH := $(shell echo $(ARCH) | sed -e s/aarch64/arm64/)
+
+ifeq ("x$(ARCH)", "xarm64")
+SUBDIRS :=
+else
+SUBDIRS :=
+endif
+
+CFLAGS := -Wall -O2 -g
+
+export CC
+export CFLAGS
+
+all:
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		mkdir -p $$BUILD_TARGET;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+install: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+run_tests: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+# Avoid any output on non arm64 on emit_tests
+emit_tests: all
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+clean:
+	@for DIR in $(SUBDIRS); do				\
+		BUILD_TARGET=$(OUTPUT)/$$DIR;			\
+		make OUTPUT=$$BUILD_TARGET -C $$DIR $@;		\
+	done
+
+.PHONY: all clean install run_tests emit_tests

diff --git a/tools/testing/selftests/arm64/README b/tools/testing/selftests/arm64/README
new file mode 100644
index 000000000000..d5aa7a2eda78
--- /dev/null
+++ b/tools/testing/selftests/arm64/README

@@ -0,0 +1,44 @@
+KSelfTest ARM64
+===============
+
+- These tests are arm64 specific and so not built or run but just skipped
+  completely when env-variable ARCH is found to be different than 'arm64'
+  and `uname -m` reports other than 'aarch64'.
+
+- Holding true the above, ARM64 KSFT tests can be run:
+
+   + as standalone (example for signal tests)
+
+      $ make -C tools/testing/selftest/arm64/signal clean
+      $ make -C tools/testing/selftest/arm64/signal \
+		INSTALL_PATH=<your-installation-path> install
+
+      and then launching on the target device inside the installed path:
+
+      device# cd <your-installed-path> && ./test_arm64_signals.sh [-k | -v]