On Fri, Apr 19, 2024 at 5:37 PM Samuel Holland
<samuel.holland@xxxxxxxxxx> wrote:
>
> Hi Atish,
>
> On 2024-04-20 10:17 AM, Atish Patra wrote:
> > For RV32, used_hw_ctrs can have more than 1 word if the firmware chooses
> > to interleave firmware/hardware counters indicies. Even though it's a
> > unlikely scenario, handle that case by iterating over all the words
> > instead of just using the first word.
> >
> > Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
> > Signed-off-by: Atish Patra <atishp@xxxxxxxxxxxx>
> > ---
> > drivers/perf/riscv_pmu_sbi.c | 21 ++++++++++++---------
> > 1 file changed, 12 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
> > index f23501898657..4eacd89141a9 100644
> > --- a/drivers/perf/riscv_pmu_sbi.c
> > +++ b/drivers/perf/riscv_pmu_sbi.c
> > @@ -652,10 +652,12 @@ static inline void pmu_sbi_stop_all(struct riscv_pmu *pmu)
> > static inline void pmu_sbi_stop_hw_ctrs(struct riscv_pmu *pmu)
> > {
> > struct cpu_hw_events *cpu_hw_evt = this_cpu_ptr(pmu->hw_events);
> > + int i;
> >
> > - /* No need to check the error here as we can't do anything about the error */
> > - sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, 0,
> > - cpu_hw_evt->used_hw_ctrs[0], 0, 0, 0, 0);
> > + for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++)
> > + /* No need to check the error here as we can't do anything about the error */
> > + sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, i * BITS_PER_LONG,
> > + cpu_hw_evt->used_hw_ctrs[i], 0, 0, 0, 0);
> > }
> >
> > /*
> > @@ -667,7 +669,7 @@ static inline void pmu_sbi_stop_hw_ctrs(struct riscv_pmu *pmu)
> > static inline void pmu_sbi_start_overflow_mask(struct riscv_pmu *pmu,
> > unsigned long ctr_ovf_mask)
> > {
> > - int idx = 0;
> > + int idx = 0, i;
> > struct cpu_hw_events *cpu_hw_evt = this_cpu_ptr(pmu->hw_events);
> > struct perf_event *event;
> > unsigned long flag = SBI_PMU_START_FLAG_SET_INIT_VALUE;
> > @@ -676,11 +678,12 @@ static inline void pmu_sbi_start_overflow_mask(struct riscv_pmu *pmu,
> > struct hw_perf_event *hwc;
> > u64 init_val = 0;
> >
> > - ctr_start_mask = cpu_hw_evt->used_hw_ctrs[0] & ~ctr_ovf_mask;
> > -
> > - /* Start all the counters that did not overflow in a single shot */
> > - sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, 0, ctr_start_mask,
> > - 0, 0, 0, 0);
> > + for (i = 0; i < BITS_TO_LONGS(RISCV_MAX_COUNTERS); i++) {
> > + ctr_start_mask = cpu_hw_evt->used_hw_ctrs[i] & ~ctr_ovf_mask;
>
> This is applying the mask for the first 32 logical counters to the both sets of
> 32 logical counters. ctr_ovf_mask needs to be 64 bits wide here, so each loop
> iteration can apply the correct half of the mask.
>
The 64bit wide support for ctr_ovf_mask is added in the next patch.
> Regards,
> Samuel
>
> > + /* Start all the counters that did not overflow in a single shot */
> > + sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, i * BITS_PER_LONG, ctr_start_mask,
> > + 0, 0, 0, 0);
> > + }
> >
> > /* Reinitialize and start all the counter that overflowed */
> > while (ctr_ovf_mask) {
>
