Regression with CTI driver on Arm Juno-r2 board - CoreSight

13 Aug 2022


      Hi Mike & all,
[ + CoreSight Mailing List ]
At my side, I found the perf cs-etm regression.  When I execute cs-etm test
with below commands:
# perf test list
  ...
  87: Check Arm CoreSight trace data recording and synthesized samples
  ...
  $ perf test -v 87
Then it's stuck and has no response.  In the console, sometimes I can
see the log:
[   94.248480] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
Apparently, there have lockup and introduces CPU stuck.  But I didn't
narrow down furthermore if is a hardware lockup or software lockup.
After git bisect, it's narrowed down the regression is related to the
commit:
e7676a00bc52b994960f89b118b0d548e4542372 is the first bad commit
commit e7676a00bc52b994960f89b118b0d548e4542372
Author: Mike Leach mike.leach@linaro.org
Date:   Wed Apr 13 22:49:25 2022 +0100
arm64: dts: juno: add CTI entries to device tree
Add Coresight Cross Trigger Interface(CTI) entries to the device tree
    for all the Juno variants.
Link: https://lore.kernel.org/r/20220413214925.30359-1-mike.leach@linaro.org
    Reviewed-by: Mathieu Poirier mathieu.poirier@linaro.org
    Signed-off-by: Mike Leach mike.leach@linaro.org
    Signed-off-by: Sudeep Holla sudeep.holla@arm.com
I built Linux kernel with below commands:
$KERNEL=/kernel/path
   $OUT=/build/out/path
pushd $KERNEL
   make defconfig O=$OUT
   ./scripts/config --file $OUT/.config -e CONFIG_BPF_SYSCALL
   ./scripts/config --file $OUT/.config -e CONFIG_BPF_JIT_ALWAYS_ON
   ./scripts/config --file $OUT/.config -e CONFIG_TRACEPOINTS
   ./scripts/config --file $OUT/.config -e CONFIG_KPROBES
   ./scripts/config --file $OUT/.config -e CONFIG_UPROBES
   ./scripts/config --file $OUT/.config -e CONFIG_KRETPROBES
   ./scripts/config --file $OUT/.config -e CONFIG_PROC_KCORE
   ./scripts/config --file $OUT/.config -e CONFIG_NOP_TRACER
   ./scripts/config --file $OUT/.config -e CONFIG_TRACER_MAX_TRACE
   ./scripts/config --file $OUT/.config -e CONFIG_RING_BUFFER
   ./scripts/config --file $OUT/.config -e CONFIG_EVENT_TRACING
   ./scripts/config --file $OUT/.config -e CONFIG_CONTEXT_SWITCH_TRACER
   ./scripts/config --file $OUT/.config -e CONFIG_TRACING
   ./scripts/config --file $OUT/.config -e CONFIG_GENERIC_TRACER
   ./scripts/config --file $OUT/.config -e CONFIG_FTRACE
   ./scripts/config --file $OUT/.config -e CONFIG_FUNCTION_TRACER
   ./scripts/config --file $OUT/.config -e CONFIG_FUNCTION_GRAPH_TRACER
   ./scripts/config --file $OUT/.config -e CONFIG_SCHED_TRACER                  
   ./scripts/config --file $OUT/.config -e CONFIG_FTRACE_SYSCALLS               
   ./scripts/config --file $OUT/.config -e CONFIG_TRACER_SNAPSHOT               
   ./scripts/config --file $OUT/.config -e CONFIG_KPROBE_EVENTS                 
   ./scripts/config --file $OUT/.config -e CONFIG_UPROBE_EVENTS                 
   ./scripts/config --file $OUT/.config -e CONFIG_BPF_EVENTS                    
   ./scripts/config --file $OUT/.config -e CONFIG_DYNAMIC_EVENTS                
   ./scripts/config --file $OUT/.config -e CONFIG_PROBE_EVENTS                  
   ./scripts/config --file $OUT/.config -e CONFIG_DYNAMIC_FTRACE                
   ./scripts/config --file $OUT/.config -e CONFIG_PID_IN_CONTEXTIDR             
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_LINKS_AND_SINKS     
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_LINK_AND_SINK_TMC   
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_CATU
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_SINK_TPIU
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_SINK_ETBV10
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_SOURCE_ETM4X
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_STM
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_CPU_DEBUG
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_CTI
   ./scripts/config --file $OUT/.config -e CONFIG_CORESIGHT_CTI_INTEGRATION_REGS
   ./scripts/config --file $OUT/.config -e CONFIG_DEBUG_INFO
   ./scripts/config --file $OUT/.config -e CONFIG_DEBUG_INFO_DWARF5
   ./scripts/config --file $OUT/.config -e CONFIG_DEBUG_INFO_BTF
   ./scripts/config --file $OUT/.config -d CONFIG_DEBUG_INFO_REDUCED
yes "" | make oldconfig O=$OUT
make -j `nproc` Image dtbs O=$OUT
   popd
When I have some free time, will come back to dig more for it.  If have
any suggestion, please let me know, I am glad to try and test at my
side.
Thanks,
Leo