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

From: Marc Zyngier
Date: Sat Dec 05 2020 - 13:23:37 EST


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 by
making it more obvious that when bits [n:n-1] are both set (with n being
the most significant bit), we pick bit (n + 1)."

With that:

Acked-by: Marc Zyngier <maz@xxxxxxxxxx>

Thanks,

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