tools: arm64: Add a Makefile for generating sysreg-defs.h

Use a common Makefile for generating sysreg-defs.h, which will soon be
needed by perf and KVM selftests. The naming scheme of the generated
macros is not expected to change, so just refer to the canonical
script/data in the kernel source rather than copying to tools.
Co-developed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Jing Zhang <jingzhangos@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231011195740.3349631-2-oliver.upton@linux.devSigned-off-by: Oliver Upton <oliver.upton@linux.dev>

tools/arch/arm64/include/.gitignore

+generated/

tools/arch/arm64/tools/Makefile

+# SPDX-License-Identifier: GPL-2.0
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+include $(srctree)/tools/scripts/Makefile.include
+
+AWK	?= awk
+MKDIR	?= mkdir
+RM	?= rm
+
+ifeq ($(V),1)
+Q =
+else
+Q = @
+endif
+
+arm64_tools_dir = $(srctree)/arch/arm64/tools
+arm64_sysreg_tbl = $(arm64_tools_dir)/sysreg
+arm64_gen_sysreg = $(arm64_tools_dir)/gen-sysreg.awk
+arm64_generated_dir = $(srctree)/tools/arch/arm64/include/generated
+arm64_sysreg_defs = $(arm64_generated_dir)/asm/sysreg-defs.h
+
+all: $(arm64_sysreg_defs)
+	@:
+
+$(arm64_sysreg_defs): $(arm64_gen_sysreg) $(arm64_sysreg_tbl)
+	$(Q)$(MKDIR) -p $(dir $@)
+	$(QUIET_GEN)$(AWK) -f $^ > $@
+
+clean:
+	$(Q)$(RM) -rf $(arm64_generated_dir)
+
+.PHONY: all clean