perf: riscv: Fix selecting counters in legacy mode
Atish Patra
atishp at rivosinc.com
Mon Jul 29 11:05:54 PDT 2024
> 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>
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