perf test: cs-etm: Test Coresight disassembly script

Run a few samples through the disassembly script and check to see that
at least one branch instruction is printed.

Signed-off-by: James Clark <james.clark@linaro.org>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Ganapatrao Kulkarni <gankulkarni@os.amperecomputing.com>
Cc: Ben Gainey <ben.gainey@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Ruidong Tian <tianruidong@linux.alibaba.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Benjamin Gray <bgray@linux.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org
Cc: John Garry <john.g.garry@oracle.com>
Cc: scclevenger@os.amperecomputing.com
Link: https://lore.kernel.org/r/20240916135743.1490403-8-james.clark@linaro.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/tests/shell/test_arm_coresight_disasm.sh

@@ -0,0 +1,65 @@
+#!/bin/sh
+# Check Arm CoreSight disassembly script completes without errors
+# SPDX-License-Identifier: GPL-2.0
+
+# The disassembly script reconstructs ranges of instructions and gives these to objdump to
+# decode. objdump doesn't like ranges that go backwards, but these are a good indication
+# that decoding has gone wrong either in OpenCSD, Perf or in the range reconstruction in
+# the script. Test all 3 parts are working correctly by running the script.
+
+skip_if_no_cs_etm_event() {
+	perf list | grep -q 'cs_etm//' && return 0
+
+	# cs_etm event doesn't exist
+	return 2
+}
+
+skip_if_no_cs_etm_event || exit 2
+
+# Assume an error unless we reach the very end
+set -e
+glb_err=1
+
+perfdata_dir=$(mktemp -d /tmp/__perf_test.perf.data.XXXXX)
+perfdata=${perfdata_dir}/perf.data
+file=$(mktemp /tmp/temporary_file.XXXXX)
+# Relative path works whether it's installed or running from repo
+script_path=$(dirname "$0")/../../scripts/python/arm-cs-trace-disasm.py
+
+cleanup_files()
+{
+	set +e
+	rm -rf ${perfdata_dir}
+	rm -f ${file}
+	trap - EXIT TERM INT
+	exit $glb_err
+}
+
+trap cleanup_files EXIT TERM INT
+
+# Ranges start and end on branches, so check for some likely branch instructions
+sep="\s\|\s"
+branch_search="\sbl${sep}b${sep}b.ne${sep}b.eq${sep}cbz\s"
+
+## Test kernel ##
+if [ -e /proc/kcore ]; then
+	echo "Testing kernel disassembly"
+	perf record -o ${perfdata} -e cs_etm//k --kcore -- touch $file > /dev/null 2>&1
+	perf script -i ${perfdata} -s python:${script_path} -- \
+		-d --stop-sample=30 2> /dev/null > ${file}
+	grep -q -e ${branch_search} ${file}
+	echo "Found kernel branches"
+else
+	# kcore is required for correct kernel decode due to runtime code patching
+	echo "No kcore, skipping kernel test"
+fi
+
+## Test user ##
+echo "Testing userspace disassembly"
+perf record -o ${perfdata} -e cs_etm//u -- touch $file > /dev/null 2>&1
+perf script -i ${perfdata} -s python:${script_path} -- \
+	-d --stop-sample=30 2> /dev/null > ${file}
+grep -q -e ${branch_search} ${file}
+echo "Found userspace branches"
+
+glb_err=0