[PATCH v3 1/4] perf: arm_cspmu: Split 64-bit write to 32-bit writes

[Ilkka Koskinen]

Hi Besar,

On Tue, 20 Jun 2023, Besar Wicaksono wrote:
>> -----Original Message-----
>> From: Ilkka Koskinen <ilkka at os.amperecomputing.com>
>> Sent: Wednesday, June 7, 2023 3:32 PM
>> To: Jonathan Corbet <corbet at lwn.net>; Will Deacon <will at kernel.org>; Mark
>> Rutland <mark.rutland at arm.com>; Besar Wicaksono
>> <bwicaksono at nvidia.com>; Suzuki K Poulose <suzuki.poulose at arm.com>;
>> Robin Murphy <robin.murphy at arm.com>
>> Cc: linux-doc at vger.kernel.org; linux-kernel at vger.kernel.org; linux-arm-
>> kernel at lists.infradead.org; Ilkka Koskinen <ilkka at os.amperecomputing.com>
>> Subject: [PATCH v3 1/4] perf: arm_cspmu: Split 64-bit write to 32-bit writes
>>
>> External email: Use caution opening links or attachments
>>
>>
>> Split the 64-bit register accesses if 64-bit access is not supported
>> by the PMU.
>>
>> Signed-off-by: Ilkka Koskinen <ilkka at os.amperecomputing.com>
>> ---
>>  drivers/perf/arm_cspmu/arm_cspmu.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c
>> b/drivers/perf/arm_cspmu/arm_cspmu.c
>> index a3f1c410b417..f8b4a149eb88 100644
>> --- a/drivers/perf/arm_cspmu/arm_cspmu.c
>> +++ b/drivers/perf/arm_cspmu/arm_cspmu.c
>> @@ -702,7 +702,10 @@ static void arm_cspmu_write_counter(struct
>> perf_event *event, u64 val)
>>         if (use_64b_counter_reg(cspmu)) {
>>                 offset = counter_offset(sizeof(u64), event->hw.idx);
>>
>> -               writeq(val, cspmu->base1 + offset);
>> +               if (supports_64bit_atomics(cspmu))
>
> Looks good to me, but this function was recently replaced by
> arm_cspmu::has_atomic_dword. Please rebase the patch.

Sure, I do that.

Cheers, Ilkka

>
> Thanks,
> Besar
>
>> +                       writeq(val, cspmu->base1 + offset);
>> +               else
>> +                       lo_hi_writeq(val, cspmu->base1 + offset);
>>         } else {
>>                 offset = counter_offset(sizeof(u32), event->hw.idx);
>>
>> --
>> 2.40.1
>
>