Hi Jeremy,

Please see several quick inline comments.

On Mon, Jun 10, 2019 at 08:49:48AM +0000, Student - Ng Yi Zher Jeremy wrote:

[...]

> ```bash
> -rw-r--r-- 1 root root 4096 1970-01-01 00:11 ecc40000.etm/addr_start
> hikey960:/sys/bus/coresight/devices # echo d10583ff > ecc40000.etm/addr_start
> 1|hikey960:/sys/bus/coresight/devices # cat ecc40000.etm/addr_start
> cat: ecc40000.etm/addr_start: Operation not permitted
> ```

After read the code, I think you need firstly to specify addr_idx:

echo 3 > ecc40000.etm/addr_idx
echo d10583ff > ecc40000.etm/addr_start

cat ecc40000.etm/addr_start

I did this as per instructed here and I was able to now read the `addr_start` file. However, there is still no trace found when I run the program.

I will like to clarify that addr_start is referring to the instruction address and not the PC counter.

> I thought it was not important that the Operation was 'not permitted'. Nonetheless, I continued with the tutorial as depicted [here](https://github.com/torvalds/linux/blob/master/Documentation/trace/coresight.txt). One thing I will like to note is that my `rwp` did move when i initially activated the sink and source. However, the 2nd time i checked the `rwp`, it went back `0x0`, the same position as that of my `rrp`.
>
> Regardless, I run the program in another kernel, performed CPU affinity to the program to point at the CPU in which the ETM is activated (in this case, CPU0). While the program is running, i looked at the `rwp/rrp` and see that neither of the pointers are moving. I thought perhaps if i perform `dd` operation, I might be able to get something.
>
> I performed `dd if=/dev/ec036000.etf of=/data/cs.bin bs=1M` but my device crashed and reboot itself without saving any files.

Could you try below commands before dd command?

echo 1 > /sys/bus/coresight/devices/ec036000.etf
# Enable ETM for CPU0
echo 1 > /sys/bus/coresight/devices/ecc40000.etm/enable_source

dd if=/dev/ec036000.etf of=/data/cs.bin bs=1M

I did this command as per usual. I even tried enabling different ETFs and alternating enable ETR to see if there are any difference. There is still no movement in my `rwp`. Even if it did (at the start), when i perform `dd` command, it reads:

```

hikey960:/sys/bus/coresight/devices # dd if=/dev/ec036000.etf of=/data/cs.bin bs=1M

0+1 records in

0+1 records out

32 bytes (32 B) copied, 0.000517 s, 60 K/s

```

I have attached the encoded trace file (cs.bin), decoded trace file (cs.log_e) and the decoded min trace file (just the addresses line: addr_e.log) in this mail. I used ptm2human API for decoding (link here: https://github.com/hwangcc23/ptm2human).

What puzzled me, furthermore, is that it seems i can never perform `dd` on ec80200.etf. Performing that command on that memory address tends to crash the AOSP in Hikey960.

Please note, you need firstly configure the address range, and then
enable the ETM and sink. If afterwards change the address range
again, you need disable etf/etm and re-enable etf/etm so can set

address range configuration into registers properly.

I thought i should detail the entire process for your expertise advise:

```

root@intern-nzyj:/data/cstrace# adb shell

hikey960:/ # cd sys/bus/coresight/devices/

hikey960:/sys/bus/coresight/devices # echo 3 > ecc40000.etm/addr_idx

hikey960:/sys/bus/coresight/devices # echo d10583ff > ecc40000.etm/addr_start

hikey960:/sys/bus/coresight/devices # echo d65f03c0 > ecc40000.etm/addr_stop

1|hikey960:/sys/bus/coresight/devices # echo 0 ffffffffffffffffff > ecc40000.etm/addr_range

1|hikey960:/sys/bus/coresight/devices # echo 1 > ec036000.etf/enable_sink

hikey960:/sys/bus/coresight/devices # echo 1 > ecc40000.etm/enable_source

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/rwp

0x7b0

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/rrp

0x7b0

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/sts

0x1

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/ctl

0x1

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/rwp

0x7b0

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/rwp

0x7b0

hikey960:/sys/bus/coresight/devices # taskset -p 8577

pid 8577's current affinity mask: 1

hikey960:/sys/bus/coresight/devices # taskset -p 8577

taskset: failed to get 8577's affinity: No such process

1|hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/rwp

0x7b0

hikey960:/sys/bus/coresight/devices # cat ec036000.etf/mgmt/rrp

0x7b0

hikey960:/sys/bus/coresight/devices # dd if=/dev/ec036000.etf of=/data/cs.bin bs=1M

0+1 records in

0+1 records out

4096 bytes (4.0 K) copied, 0.001610 s, 2.4 M/s

hikey960:/sys/bus/coresight/devices # exit

root@intern-nzyj:/data/cstrace# adb pull /data/cs.bin

/data/cs.bin: 1 file pulled. 0.1 MB/s (4096 bytes in 0.046s)

root@intern-nzyj:/data/cstrace# /src/ptm2human/ptm2human -e -i cs.bin > cs.log_e

```

I don't try at my side, if have any question or issue, please report
back so I can test on Hikey960.

Thanks,

Leo Yan

Thank you very much for your kind responses and patience!

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