Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 5 Jun 2017 17:11:37 +0100 | From | Will Deacon <> | Subject | Re: [PATCH v4 4/5] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension |
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On Mon, Jun 05, 2017 at 10:55:16AM -0500, Kim Phillips wrote: > On Mon, 5 Jun 2017 16:22:56 +0100 > Will Deacon <will.deacon@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; > > + > > + return 0; > > +} > > AFAICT, my comments from the last submission have still not been fully > addressed: > > http://lists.infradead.org/pipermail/linux-arm-kernel/2017-May/508027.html
To be frank, I really don't plan to address them and, even if I did, I would trust Mark to NAK the change. If you're desperate for pr_debug, I'll add it to keep you happy, but anything more than that needs to come in the form of a separate patch submission addressing the wider problem of error reporting from PMU drivers back to userspace. Patches welcome, but I suspect you're still busy working on the tools code.
Do you have any constructive comments on the patch?
Will
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