perf: riscv: Fix selecting counters in legacy mode

[Alexandre Ghiti]

Hi Dmitry,

On 29/07/2024 20:05, Atish Patra wrote:
>> It is required to check event type before checking event config.
>> Events with the different types can have the same config.
>> This check is missed for legacy mode code
>>
>> For such perf usage:
>>      sysctl -w kernel.perf_user_access=2
>>      perf stat -e cycles,L1-dcache-loads --
>> driver will try to force both events to CYCLE counter.
>>
>> This commit implements event type check before forcing
>> events on the special counters.
>>
>> Signed-off-by: Shifrin Dmitry <dmitry.shifrin at syntacore.com>
>> ---
>>   drivers/perf/riscv_pmu_sbi.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
>> index 36d128ff166f..bf14ab282e11 100644
>> --- a/drivers/perf/riscv_pmu_sbi.c
>> +++ b/drivers/perf/riscv_pmu_sbi.c
>> @@ -416,7 +416,7 @@ static int pmu_sbi_ctr_get_idx(struct perf_event *event)
>>   	 * but not in the user access mode as we want to use the other counters
>>   	 * that support sampling/filtering.
>>   	 */
>> -	if (hwc->flags & PERF_EVENT_FLAG_LEGACY) {
>> +	if ((hwc->flags & PERF_EVENT_FLAG_LEGACY) && (event->attr.type == PERF_TYPE_HARDWARE)) {
>>   		if (event->attr.config == PERF_COUNT_HW_CPU_CYCLES) {
>>   			cflags |= SBI_PMU_CFG_FLAG_SKIP_MATCH;
>>   			cmask = 1;
>>
> Nice catch.
> Reviewed-by: Atish Patra <atishp at rivosinc.com>


Can you add a Fixes tag? No need to send another version, just reply 
with the corresponding tag and b4 will grab it.

Thanks!

Alex


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