[PATCH v3 2/2] clocksource: arm_arch_timer: Correct fault programming of CNTKCTL_EL1.EVNTI

Marc Zyngier maz at kernel.org
Sat Dec 5 13:22:04 EST 2020

Hi Daniel,

On 2020-12-05 11:15, Daniel Lezcano wrote:
> Hi Marc,
> are you fine with this patch ?

I am, although there still isn't any justification for the pos/lsb
rework in the commit message (and calling that variable lsb is somewhat
confusing). If you are going to apply it, please consider adding
the additional comment below.

> On 04/12/2020 08:31, Keqian Zhu wrote:
>> ARM virtual counter supports event stream, it can only trigger an 
>> event
>> when the trigger bit (the value of CNTKCTL_EL1.EVNTI) of CNTVCT_EL0 
>> changes,
>> so the actual period of event stream is 2^(cntkctl_evnti + 1). For 
>> example,
>> when the trigger bit is 0, then virtual counter trigger an event for 
>> every
>> two cycles.

"While we're at it, rework the way we compute the trigger bit position 
  making it more obvious that when bits [n:n-1] are both set (with n 
  the most significant bit), we pick bit (n + 1)."

With that:

Acked-by: Marc Zyngier <maz at kernel.org>


Jazz is not dead. It just smells funny...

More information about the linux-arm-kernel mailing list