Coresight ETF trace dump failed in Juno r1 with 4.8-rc8

[Venkatesh Vivekanandan]

On Tue, Oct 4, 2016 at 7:59 PM, Suzuki K Poulose <Suzuki.Poulose at arm.com> wrote:
> On 04/10/16 06:37, Venkatesh Vivekanandan wrote:
>>
>> On Mon, Oct 3, 2016 at 6:44 PM, Sudeep Holla <sudeep.holla at arm.com> wrote:
>>>
>>> Hi Venkatesh,
>>>
>>> On 03/10/16 12:36, Venkatesh Vivekanandan wrote:
>>>>
>>>>
>>>> Hi All,
>>>>
>>>> I am trying to collect ETF trace from Juno R1 and could see "cpu
>>>> stall" while dumping the trace. Attached is the log of sequence
>>>> followed. Was trying to collect the trace data from hardware and see
>>>> if it is any valid data. Am I missing anything here?.
>>>>
>>>
>>> There are few fixes from me and Suzuki queued for v4.9.
>>> Can you check if this issue persists even on linux-next ?
>>
>>
>> Issue is the same in linux-next as well. Please find the attached log.
>>
>> linaro-test [rc=0]# dd if=/dev/20010000.etf of=/cstrace.bin bs=1
>> [  120.009698] INFO: rcu_preempt detected stalls on CPUs/tasks:
>> [  120.015307]  2-...: (1 GPs behind) idle=f11/140000000000000/0
>> softirq=224/224 fqs=1903
>> [  120.023226]  (detected by 1, t=5255 jiffies, g=-1, c=-2, q=19)
>> [  120.029001] Task dump for CPU 2:
>> [  120.032190] dd              R  running task        0  1270   1267
>> 0x00000002
>> [  120.039172] Call trace:
>> [  120.041594] [<ffff000008085534>] __switch_to+0xc8/0xd4
>> [  120.046675] [<0000000000020000>] 0x20000
>>
>> Steps followed,
>> # git clone
>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>> linux-next
>> # cd linux-next
>> # make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
>> # make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig  <---
>> enable coresight
>> # make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- -j8 Image
>> # make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- dtbs
>> # arch/arm64/boot/Image <--- copied this kernel
>> # arch/arm64/boot/dts/arm/juno-r1.dtb <--- copied this dtb
>>
>> Top commit in linux-next is,
>>
>> commit c7d3b912180a9bb0733e5cfab84e5a7493dd3599
>> Author: Stephen Rothwell <sfr at canb.auug.org.au>
>> Date:   Tue Oct 4 14:52:03 2016 +1100
>>
>>     Add linux-next specific files for 20161004
>
>
> Can't reproduce it here either.
>
> root at localhost:/sys/bus/coresight/devices# echo 1 > 20010000.etf/enable_sink
> root at localhost:/sys/bus/coresight/devices# echo 1 >
> 22140000.etm/enable_source
> root at localhost:/sys/bus/coresight/devices# dd if=/dev/20010000.etf bs=1
> of=/root/etr.bin
> 65536+0 records in
> 65536+0 records out
> 65536 bytes (66 kB) copied, 0.227546 s, 288 kB/s
> root at localhost:/sys/bus/coresight/devices# dd if=/dev/20010000.etf bs=1
> of=/root/etr.bin
> 65536+0 records in
> 65536+0 records out
> 65536 bytes (66 kB) copied, 0.233527 s, 281 kB/s
> root at localhost:/sys/bus/coresight/devices# echo 0 > 20010000.etf/enable_sink
> root at localhost:/sys/bus/coresight/devices# dd if=/dev/20010000.etf bs=1
> of=/root/etr.bin
> 65536+0 records in
> 65536+0 records out
> 65536 bytes (66 kB) copied, 0.474943 s, 138 kB/s
>
> FWIW, here is my firmware version :
>
> NOTICE:  Booting Trusted Firmware
> NOTICE:  BL1: v1.1(release):e04723e21362
> NOTICE:  BL1: Built : 15:39:56, Sep  1 2015
> NOTICE:  BL1: Booting BL2
> NOTICE:  BL2: v1.1(release):e04723e21362
> NOTICE:  BL2: Built : 15:42:30, Sep  1 2015
> NOTICE:  BL1: Booting BL3-1
> NOTICE:  BL3-1: v1.1(release):604d5da6f2aa
> NOTICE:  BL3-1: Built : 14:50:36, Sep 10 2015
> UEFI firmware (version ea31f8e built at 16:35:17 on Aug  5 2015)
>

Hang is seen while trying to dump trace _after_ disabling the ETM
source. Is it not supposed to work?.
It works fine, when dumped before disabling ETM source. Please find
the log below.

linaro-test [rc=0]# echo 1 > 20010000.etf/enable_sink
linaro-test [rc=0]# echo 1 > 22140000.etm/enable_source
[   91.792145] coresight-tmc 20010000.etf: TMC-ETB/ETF enabled
[   91.797719] coresight-funnel 20040000.main-funnel: FUNNEL inport 0 enabled
[   91.804552] coresight-funnel 220c0000.cluster0-funnel: FUNNEL
inport 1 enabled
[   91.815990] coresight-etm4x 22140000.etm: ETM tracing enabled
linaro-test [rc=0]# dd if=/dev/20010000.etf of=/cstrace.bin bs=1
[  108.105492] coresight-tmc 20010000.etf: TMC read start
[  108.404335] coresight-tmc 20010000.etf: TMC read end
65536+0 records in
65536+0 records out
linaro-test [rc=0]# echo 0 > 20010000.etf/enable_sink
linaro-test [rc=0]# dd if=/dev/20010000.etf of=/cstrace.bin bs=1
[  125.069740] coresight-tmc 20010000.etf: TMC read start
[  125.184370] coresight-tmc 20010000.etf: TMC read end
65536+0 records in
65536+0 records out
linaro-test [rc=0]# echo 0 > 22140000.etm/enable_source
[  140.271163] coresight-etm4x 22140000.etm: ETM tracing disabled
[  140.276964] coresight-funnel 220c0000.cluster0-funnel: FUNNEL
inport 1 disabled
[  140.284211] coresight-funnel 20040000.main-funnel: FUNNEL inport 0 disabled
[  140.291128] coresight-tmc 20010000.etf: TMC-ETB/ETF disabled
linaro-test [rc=0]# dd if=/dev/20010000.etf of=/cstrace.bin bs=1
<---- It hangs here...

My firmware version,

NOTICE:  Booting Trusted Firmware
NOTICE:  BL1: v1.1(debug):4a1dcde
NOTICE:  BL1: Built : 17:54:40, Nov 24 2015
NOTICE:  BL1: Booting BL2
NOTICE:  BL2: v1.1(debug):4a1dcde
NOTICE:  BL2: Built : 17:54:40, Nov 24 2015
NOTICE:  BL1: Booting BL3-1
NOTICE:  BL3-1: v1.1(debug):4a1dcde
NOTICE:  BL3-1: Built : 17:54:40, Nov 24 2015
UEFI firmware (version 9ed6f7e built at 17:54:28 on Nov 24 2015)

>
> Cheers
> Suzuki
>