There are two reasons to do this, firstly there is a shellcheck warning in cs_etm_dev_name(), which can be completely deleted. And secondly the current iteration method doesn't support systems with both ETE and ETM because it picks one or the other. There isn't a known system with this configuration, but it could happen in the future.
Iterating over all the sources for each CPU can be done by going through /sys/bus/event_source/devices/cs_etm/cpu* and following the symlink back to the Coresight device in /sys/bus/coresight/devices. This will work whether the device is ETE, ETM or any future name, and is much simpler and doesn't require any hard coded version numbers
Suggested-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: James Clark james.clark@arm.com ---
This was discussed here previously: https://lore.kernel.org/all/20230929041133.95355-2-atrajeev@linux.vnet.ibm.c...
I chose not to add a fixes tag like the original because shellcheck isn't part of the build so it doesn't really fix any real issue yet and is just a refactor.
tools/perf/tests/shell/test_arm_coresight.sh | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/tools/perf/tests/shell/test_arm_coresight.sh b/tools/perf/tests/shell/test_arm_coresight.sh index fe78c4626e45..65dd85207125 100755 --- a/tools/perf/tests/shell/test_arm_coresight.sh +++ b/tools/perf/tests/shell/test_arm_coresight.sh @@ -11,19 +11,6 @@
glb_err=0
-cs_etm_dev_name() { - cs_etm_path=$(find /sys/bus/event_source/devices/cs_etm/ -name cpu* -print -quit) - trcdevarch=$(cat ${cs_etm_path}/mgmt/trcdevarch) - archhver=$((($trcdevarch >> 12) & 0xf)) - archpart=$(($trcdevarch & 0xfff)) - - if [ $archhver -eq 5 -a "$(printf "0x%X\n" $archpart)" = "0xA13" ] ; then - echo "ete" - else - echo "etm" - fi -} - skip_if_no_cs_etm_event() { perf list | grep -q 'cs_etm//' && return 0
@@ -149,7 +136,9 @@ arm_cs_iterate_devices() {
arm_cs_etm_traverse_path_test() { # Iterate for every ETM device - for dev in /sys/bus/coresight/devices/$(cs_etm_dev_name)*; do + for dev in /sys/bus/event_source/devices/cs_etm/cpu*; do + # Canonicalize the path + dev=`readlink -f $dev`
# Find the ETM device belonging to which CPU cpu=`cat $dev/cpu`