Hello,
I would like to test the System Trace Macrocell (STM) on db410c and tried following the steps at [1]. I am using linux kernel version 5.9.0-qcomlt-arm64 and I believe the steps described in the linked post are for an earlier version of the kernel.
I tried those steps (but slightly adjusted so it is conform to the sysfs path on 5.9.0-qcomlt-arm64) and it fails when trying to link: *$ echo 802000.stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm0 > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument
I'd be happy to test the steps on a working version of the kernel. Does anyone know for which kernel version the steps in [1] are? I'd also be grateful if someone has the right steps to test STM with ftrace on the recent kernel versions.
Thank you, Enes
[1] https://lists.linaro.org/pipermail/coresight/2018-August/001653.html
By installing an older kernel version (4.14) used in Linaro Linux release 18.01 [1] I was able to successfully execute all steps in [2].
[1] https://releases.linaro.org/96boards/dragonboard410c/linaro/debian/18.01/ [2] https://lists.linaro.org/pipermail/coresight/2018-August/001653.html
On Wed, Mar 17, 2021 at 6:56 PM Enes Göktaş enes.goktas@gmail.com wrote:
Hello,
I would like to test the System Trace Macrocell (STM) on db410c and tried following the steps at [1]. I am using linux kernel version 5.9.0-qcomlt-arm64 and I believe the steps described in the linked post are for an earlier version of the kernel.
I tried those steps (but slightly adjusted so it is conform to the sysfs path on 5.9.0-qcomlt-arm64) and it fails when trying to link: *$ echo 802000.stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm0 > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument
I'd be happy to test the steps on a working version of the kernel. Does anyone know for which kernel version the steps in [1] are? I'd also be grateful if someone has the right steps to test STM with ftrace on the recent kernel versions.
Thank you, Enes
[1] https://lists.linaro.org/pipermail/coresight/2018-August/001653.html
Hi Enes,
On Wed, Mar 17, 2021 at 06:56:10PM -0400, Enes Göktaş wrote:
Hello,
I would like to test the System Trace Macrocell (STM) on db410c and tried following the steps at [1]. I am using linux kernel version 5.9.0-qcomlt-arm64 and I believe the steps described in the linked post are for an earlier version of the kernel.
I tried those steps (but slightly adjusted so it is conform to the sysfs path on 5.9.0-qcomlt-arm64) and it fails when trying to link: *$ echo 802000.stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm0 > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument
I'd be happy to test the steps on a working version of the kernel. Does anyone know for which kernel version the steps in [1] are? I'd also be grateful if someone has the right steps to test STM with ftrace on the recent kernel versions.
I think you encouter the issue for STM has changed to use configfs.
Firstly you need to check what's the STM device name by reading the folder /sys/bus/coresight/devices:
# ls /sys/bus/coresight/devices/ etm0 etm1 etm2 etm3 funnel0 funnel1 replicator0 stm0 tmc_etf0 tmc_etr0 tpiu0
So you could see with the mainline kernel, the STM device name is "stm0", please note "802000.stm" is an old naming convension.
Then, need to set up configFS so that you could specify which data stream for STM (e.g. console, ftrace, etc). Below is an example to set ftrace function tracing for STM:
# Enable hardware path (STM -> ETF or, you could set STM -> ETR) 1. echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink 2. echo 1 > /sys/bus/coresight/devices/stm0/enable_source
# Config STM functionality for Ftrace 3. mkdir -p /config 4. mount -t configfs none /config 5. mkdir /config/stp-policy/stm0.policy 6. mkdir /config/stp-policy/stm0.policy/ftrace 7. echo stm0 > /sys/class/stm_source/ftrace/stm_source_link
# Enable Ftrace function tracing 8. echo function > /sys/kernel/debug/tracing/current_tracer 9. echo '*' > /sys/kernel/debug/tracing/set_ftrace_filter
Thanks, Leo
Thank you for the updated steps Leo!
On Fri, Mar 19, 2021 at 12:39 AM Leo Yan leo.yan@linaro.org wrote:
Hi Enes,
On Wed, Mar 17, 2021 at 06:56:10PM -0400, Enes Göktaş wrote:
Hello,
I would like to test the System Trace Macrocell (STM) on db410c and tried following the steps at [1]. I am using linux kernel version 5.9.0-qcomlt-arm64 and I believe the steps described in the
linked
post are for an earlier version of the kernel.
I tried those steps (but slightly adjusted so it is conform to the sysfs path on 5.9.0-qcomlt-arm64) and it fails when trying to link: *$ echo 802000.stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument *$ echo stm0 > **/sys/class/stm_source/ftrace/stm_source_link* bash: echo: write error: Invalid argument
I'd be happy to test the steps on a working version of the kernel. Does anyone know for which kernel version the steps in [1] are? I'd also be grateful if someone has the right steps to test STM with
ftrace
on the recent kernel versions.
I think you encouter the issue for STM has changed to use configfs.
Firstly you need to check what's the STM device name by reading the folder /sys/bus/coresight/devices:
# ls /sys/bus/coresight/devices/ etm0 etm1 etm2 etm3 funnel0 funnel1 replicator0 stm0 tmc_etf0 tmc_etr0 tpiu0
So you could see with the mainline kernel, the STM device name is "stm0", please note "802000.stm" is an old naming convension.
Then, need to set up configFS so that you could specify which data stream for STM (e.g. console, ftrace, etc). Below is an example to set ftrace function tracing for STM:
# Enable hardware path (STM -> ETF or, you could set STM -> ETR)
- echo 1 > /sys/bus/coresight/devices/tmc_etf0/enable_sink
- echo 1 > /sys/bus/coresight/devices/stm0/enable_source
# Config STM functionality for Ftrace 3. mkdir -p /config 4. mount -t configfs none /config 5. mkdir /config/stp-policy/stm0.policy 6. mkdir /config/stp-policy/stm0.policy/ftrace 7. echo stm0 > /sys/class/stm_source/ftrace/stm_source_link
# Enable Ftrace function tracing 8. echo function > /sys/kernel/debug/tracing/current_tracer 9. echo '*' > /sys/kernel/debug/tracing/set_ftrace_filter
Thanks, Leo
-
Enes Göktaş -
Leo Yan