Re: [PATCH v3 08/20] coresight: allow etm4x to be built as a module

[Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>]

Hi Tingwei,

On 2020-07-20 12:28, Sai Prakash Ranjan wrote:
> Hi Tingwei,
> 
> On 2020-07-17 11:15, Tingwei Zhang wrote:
>> From: Kim Phillips <kim.phillips@arm.com>
>> 
>> Allow to build coresight-etm4x as a module, for ease of development.
>> 
>> - Kconfig becomes a tristate, to allow =m
>> - append -core to source file name to allow module to
>>   be called coresight-etm4x by the Makefile
>> - add an etm4_remove function, for module unload
>> - add a MODULE_DEVICE_TABLE for autoloading on boot
>> 
>> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
>> Cc: Leo Yan <leo.yan@linaro.org>
>> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
>> Cc: Randy Dunlap <rdunlap@infradead.org>
>> Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Russell King <linux@armlinux.org.uk>
>> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
>> Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
>> ---
>>  drivers/hwtracing/coresight/Kconfig           |  5 ++-
>>  drivers/hwtracing/coresight/Makefile          |  4 +--
>>  ...resight-etm4x.c => coresight-etm4x-core.c} | 31 
>> ++++++++++++++++++-
>>  3 files changed, 36 insertions(+), 4 deletions(-)
>>  rename drivers/hwtracing/coresight/{coresight-etm4x.c =>
>> coresight-etm4x-core.c} (98%)
>> 
> 
> <snip>...
> 
> Thanks for adding this support. etm4_cpu_pm_unregister() is dropped
> now with change to ETM PM code.
> You can base the patches on coresight-next -
> https://git.linaro.org/kernel/coresight.git/log/?h=next
> 
> Also I am trying this series on SDM845 MTP (5.8.0-rc5) with Debian 
> distribution,
> I see below warning when trying to disable ETM, logs below:
> 
> root@linaro-developer:~# lsmod
> Module                  Size  Used by
> cpufreq_powersave      16384  0
> cpufreq_conservative    16384  0
> msm                   856064  1
> coresight_stm          24576  0
> crct10dif_ce           20480  1
> stm_core               28672  1 coresight_stm
> i2c_qcom_geni          24576  0
> qcom_rng               16384  0
> coresight_tmc          40960  0
> coresight_funnel       20480  0
> coresight_etm4x        61440  0
> coresight_replicator    20480  0
> camcc_sdm845           49152  0
> ath10k_snoc            53248  0
> socinfo                20480  0
> ip_tables              32768  0
> x_tables               45056  1 ip_tables
> ipv6                  458752  26
> nf_defrag_ipv6         24576  1 ipv6
> root@linaro-developer:~#
> root@linaro-developer:~# echo 1 >
> /sys/bus/coresight/devices/tmc_etr0/enable_sink
> root@linaro-developer:~# echo 1 > 
> /sys/bus/coresight/devices/etm0/enable_source
> root@linaro-developer:~# echo 0 > 
> /sys/bus/coresight/devices/etm0/enable_source
> [  332.855363] ------------[ cut here ]------------
> [  332.860175] WARNING: CPU: 0 PID: 0 at
> drivers/hwtracing/coresight/coresight-core.c:227
> coresight_disclaim_device_unlocked+0x28/0x50
> [  332.872177] Modules linked in: cpufreq_powersave
> cpufreq_conservative msm(+) coresight_stm crct10dif_ce stm_core
> i2c_qcom_geni qcom_rng coresi
> ght_tmc coresight_funnel coresight_etm4x coresight_replicator
> camcc_sdm845 ath10k_snoc socinfo ip_tables x_tables ipv6
> nf_defrag_ipv6
> [  332.897043] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G      D W
>   5.8.0-rc5-next-20200716-00040-g50ad3222c13f-dirty #80
> [  332.908330] Hardware name: Qualcomm Technologies, Inc. SDM845 MTP 
> (DT)
> [  332.914969] pstate: 80400085 (Nzcv daIf +PAN -UAO BTYPE=--)
> [  332.920643] pc : coresight_disclaim_device_unlocked+0x28/0x50
> [  332.926543] lr : etm4_disable_hw+0xd8/0x128 [coresight_etm4x]
> [  332.932391] sp : ffff800010003ed0
> [  332.935775] x29: ffff800010003ed0 x28: ffffb05e1bd13980
> [  332.941193] x27: 0000004d7fb06ef3 x26: ffff800010004000
> [  332.946606] x25: 0000000000000000 x24: ffffb05e1bd03cc0
> [  332.952022] x23: 0000000000000000 x22: 0000000000000000
> [  332.957436] x21: ffff800010c73c00 x20: ffff000175547400
> [  332.962851] x19: ffff8000103af000 x18: 0000000000000005
> [  332.968267] x17: 0000000000000000 x16: ffffb05e1a875f38
> [  332.973678] x15: 0000000000000000 x14: ffffb05e1bd13980
> [  332.979093] x13: ffff4fa361082000 x12: 000000003474591d
> [  332.984507] x11: 0000000000000000 x10: 0000000000001000
> [  332.989920] x9 : ffffb05e19a81800 x8 : 000001b2b5503510
> [  332.995336] x7 : 000000b2b5503510 x6 : 000000003fd5ea33
> [  333.000749] x5 : 00ffffffffffffff x4 : 000000000000b2be
> [  333.006162] x3 : ffff0001725c8150 x2 : ffff8000103af168
> [  333.011574] x1 : 0000000000000000 x0 : ffff8000103affa4
> [  333.016993] Call trace:
> [  333.019516]  coresight_disclaim_device_unlocked+0x28/0x50
> [  333.025035]  etm4_disable_hw+0xd8/0x128 [coresight_etm4x]
> [  333.030552]  flush_smp_call_function_queue+0x154/0x250
> [  333.035795]  generic_smp_call_function_single_interrupt+0x18/0x20
> [  333.041999]  handle_IPI+0x32c/0x390
> [  333.045569]  gic_handle_irq+0x15c/0x160
> [  333.049489]  el1_irq+0xb8/0x180
> [  333.052709]  cpuidle_enter_state+0xac/0x4e8
> [  333.056983]  cpuidle_enter+0x3c/0x50
> [  333.060646]  call_cpuidle+0x40/0x70
> [  333.064210]  do_idle+0x20c/0x290
> [  333.067516]  cpu_startup_entry+0x28/0x70
> [  333.071528]  rest_init+0xdc/0xe8
> [  333.074847]  arch_call_rest_init+0x14/0x1c
> [  333.079027]  start_kernel+0x4e0/0x518
> [  333.082764] ---[ end trace 162d5cef8c2b863b ]---
> root@linaro-developer:~#
> 

I found that above warning is not due to your changes. If I add
"arm,coresight-loses-context-with-cpu" to SDM845 ETM nodes then
I don't see these warnings, so will add them since idle support
is present on sdm845.

Thanks,
Sai

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