Performance Monitor Counters (Firefly-RK3399)

rezaetemadi

Hello

I am using Ubuntu 16.04  with kernel 4.4.55 which I believe it is the latest (build from the master branch).
I noticed that performance monitor counters for both A53 and A72 do not work. When I am
trying to access from the user space, I get "illegal instruction".
Normally this happens if user level access is not enabled. But  I have enabled PMU user level access
by loading a kernel module.
In the Linux boot logs I am seeing the following message which indicates hardware supports
CPU performance monitor counters.

firefly@firefly:~$ dmesg | grep PMU
[    0.336204] hw perfevents: enabled with armv8_cortex_a53 PMU driver, 7 counters available
[    0.337025] hw perfevents: enabled with armv8_cortex_a72 PMU driver, 7 counters available

Has anybody tested this feature on this board?
Am I missing a steps?.

This process works on other platforms. Any hint that why this is broken on Firefly-RK3399?

Regards, Reza