Re: [PATCH v2 1/2] clocksource: arm_arch_timer: Use stable count reader in erratum sne

From: zhukeqian
Date: Fri Dec 04 2020 - 02:37:12 EST


Hi Marc,

On 2020/12/3 22:58, Marc Zyngier wrote:
> On 2020-08-18 04:28, Keqian Zhu wrote:
>> In commit 0ea415390cd3 ("clocksource/arm_arch_timer: Use arch_timer_read_counter
>> to access stable counters"), we separate stable and normal count reader to omit
>> unnecessary overhead on systems that have no timer erratum.
>>
>> However, in erratum_set_next_event_tval_generic(), count reader becomes normal
>> reader. This converts it to stable reader.
>>
>> Fixes: 0ea415390cd3 ("clocksource/arm_arch_timer: Use
>> arch_timer_read_counter to access stable counters")
>
> On a single line.
Addressed. Thanks.

>
>> Signed-off-by: Keqian Zhu <zhukeqian1@xxxxxxxxxx>
>> ---
>> drivers/clocksource/arm_arch_timer.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/clocksource/arm_arch_timer.c
>> b/drivers/clocksource/arm_arch_timer.c
>> index 6c3e841..777d38c 100644
>> --- a/drivers/clocksource/arm_arch_timer.c
>> +++ b/drivers/clocksource/arm_arch_timer.c
>> @@ -396,10 +396,10 @@ static void
>> erratum_set_next_event_tval_generic(const int access, unsigned long
>> ctrl &= ~ARCH_TIMER_CTRL_IT_MASK;
>>
>> if (access == ARCH_TIMER_PHYS_ACCESS) {
>> - cval = evt + arch_counter_get_cntpct();
>> + cval = evt + arch_counter_get_cntpct_stable();
>> write_sysreg(cval, cntp_cval_el0);
>> } else {
>> - cval = evt + arch_counter_get_cntvct();
>> + cval = evt + arch_counter_get_cntvct_stable();
>> write_sysreg(cval, cntv_cval_el0);
>> }
>
> With that fixed:
>
> Acked-by: Marc Zyngier <maz@xxxxxxxxxx>
>
> This should go via the clocksource tree.
Added Cc to it's maintainers, thanks.

>
> Thanks,
>
> M.
Cheers,
Keqian