[PATCH 01/13] kselftest: arm64: introduce new boilerplate code

[Cristian Marussi <cristian.marussi@arm.com>]

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]
+
+   + within the KSelfTest framework using standard Linux top-level-makefile
+     targets:
+
+      $ make TARGETS=arm64 kselftest-clean
+      $ make TARGETS=arm64 kselftest
+
+   Further details on building and running KFST can be found in:
+     Documentation/dev-tools/kselftest.rst
+
+- Tests can depend on some arch-specific definitions which can be found in a
+  standard Kernel Headers installation in $(top_srcdir)/usr/include.
+  Such Kernel Headers are automatically installed (via make headers_install)
+  by KSFT framework itself in a dedicated directory when tests are launched
+  via KSFT itself; when running standalone, instead, a Warning is issued
+  if such headers cannot be found somewhere (we try to guess a few standard
+  locations anyway)
+
+- Some of these tests may be related to possibly not implemented ARMv8
+  features: depending on their implementation status on the effective HW
+  we'll expect different results. The tests' harness will take care to check
+  at run-time if the required features are supported and will act accordingly.
+  Moreover, in order to avoid any kind of compile-time dependency on the
+  toolchain (possibly due to the above mentioned not-implemented features),
+  we make strictly use of direct 'S3_ sysreg' raw-encoding while checking for
+  those features and/or lookin up sysregs.
-- 
2.17.1