perf test: Add asm pureloop test tool

Add test tool to be driven by further test scripts. This tool is pure
arm64 ASM with no libc usage to ensure it is the same exact binary/code
every time so it can also be re-used for many uses. It just loops for a
given fixed number of loops.

Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Carsten Haitzler <carsten.haitzler@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: coresight@lists.linaro.org
Link: https://lore.kernel.org/r/20220909152803.2317006-4-carsten.haitzler@foss.arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/shell/coresight/Makefile

@@ -4,7 +4,8 @@ include ../../../../../tools/scripts/Makefile.include
 include ../../../../../tools/scripts/Makefile.arch
 include ../../../../../tools/scripts/utilities.mak
 
-SUBDIRS =
+SUBDIRS = \
+	asm_pure_loop
 
 all: $(SUBDIRS)
 $(SUBDIRS):

tools/perf/tests/shell/coresight/asm_pure_loop/.gitignore

@@ -0,0 +1 @@
+asm_pure_loop

tools/perf/tests/shell/coresight/asm_pure_loop/Makefile

@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0
+# Carsten Haitzler <carsten.haitzler@arm.com>, 2021
+
+include ../Makefile.miniconfig
+
+# Binary to produce
+BIN=asm_pure_loop
+# Any linking/libraries needed for the binary - empty if none needed
+LIB=
+
+all: $(BIN)
+
+$(BIN): $(BIN).S
+ifdef CORESIGHT
+ifeq ($(ARCH),arm64)
+# Build line - this is raw asm with no libc to have an always exact binary
+	$(Q)$(CC) $(BIN).S -nostdlib -static -o $(BIN) $(LIB)
+endif
+endif
+
+install-tests: all
+ifdef CORESIGHT
+ifeq ($(ARCH),arm64)
+# Install the test tool in the right place
+	$(call QUIET_INSTALL, tests) \
+		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/$(INSTDIR_SUB)/$(BIN)'; \
+		$(INSTALL) $(BIN) '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/$(INSTDIR_SUB)/$(BIN)/$(BIN)'
+endif
+endif
+
+clean:
+	$(Q)$(RM) -f $(BIN)
+
+.PHONY: all clean install-tests

tools/perf/tests/shell/coresight/asm_pure_loop/asm_pure_loop.S

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Tamas Zsoldos <tamas.zsoldos@arm.com>, 2021 */
+
+.globl _start
+_start:
+	mov	x0, 0x0000ffff
+	mov	x1, xzr
+loop:
+	nop
+	nop
+	cbnz	x1, noskip
+	nop
+	nop
+	adrp	x2, skip
+	add 	x2, x2, :lo12:skip
+	br	x2
+	nop
+	nop
+noskip:
+	nop
+	nop
+skip:
+	sub	x0, x0, 1
+	cbnz	x0, loop
+
+	mov	x0, #0
+	mov	x8, #93 // __NR_exit syscall
+	svc	#0