On Thu, 18 May 2017 18:24:32 +0100
Will Deacon <will.dea...@arm.com> wrote:
> +/* Perf callbacks */
> +static int arm_spe_pmu_event_init(struct perf_event *event)
> +{
> + u64 reg;
> + struct perf_event_attr *attr = &event->attr;
> + struct arm_spe_pmu *spe_pmu = to_spe_pmu(event->pmu);
> +
> + /* This is, of course, deeply driver-specific */
> + if (attr->type != event->pmu->type)
> + return -ENOENT;
> +
> + if (event->cpu >= 0 &&
> + !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus))
> + return -ENOENT;
> +
> + if (arm_spe_event_to_pmsevfr(event) & PMSEVFR_EL1_RES0)
> + return -EOPNOTSUPP;
> +
> + if (event->hw.sample_period < spe_pmu->min_period ||
> + event->hw.sample_period & PMSIRR_EL1_IVAL_MASK)
> + return -EOPNOTSUPP;
> +
> + if (attr->exclude_idle)
> + return -EOPNOTSUPP;
> +
> + /*
> + * Feedback-directed frequency throttling doesn't work when we
> + * have a buffer of samples. We'd need to manually count the
> + * samples in the buffer when it fills up and adjust the event
> + * count to reflect that. Instead, force the user to specify a
> + * sample period instead.
> + */
> + if (attr->freq)
> + return -EINVAL;
> +
> + reg = arm_spe_event_to_pmsfcr(event);
> + if ((reg & BIT(PMSFCR_EL1_FE_SHIFT)) &&
> + !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT))
> + return -EOPNOTSUPP;
> +
> + if ((reg & BIT(PMSFCR_EL1_FT_SHIFT)) &&
> + !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP))
> + return -EOPNOTSUPP;
> +
> + if ((reg & BIT(PMSFCR_EL1_FL_SHIFT)) &&
> + !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT))
> + return -EOPNOTSUPP;
I've consistently brought up lack of proper user error messaging in all
previous submissions of this driver:
Jan. 10 2017 (first RFC):
https://www.spinics.net/lists/arm-kernel/msg553322.html
Jan. 13 (second RFC):
https://patchwork.kernel.org/patch/9515967/
[I just went ahead and re-read https://lkml.org/lkml/2015/8/26/661 and
still think it's not a reason to not do this]
30 Jan 2017 (first PATCH series):
https://www.spinics.net/lists/arm-kernel/msg559232.html
6 apr 2017 (PATCH v2 series):
https://lkml.org/lkml/2017/4/6/790
AFAICT, my comments hold, yet the driver still gets resubmitted without
them being addressed. How do we get out of this loop?
Kim
