[PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension
From: Kim Phillips <hidden>
Date: 2017-01-30 19:29:35
Also in:
lkml
Subsystem:
arm pmu profiling and debugging, the rest · Maintainers:
Will Deacon, Mark Rutland, Linus Torvalds
On Fri, 27 Jan 2017 18:07:48 +0000 Will Deacon [off-list ref] 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;
+
+ if (is_kernel_in_hyp_mode()) {
+ if (attr->exclude_kernel != attr->exclude_hv)
+ return -EOPNOTSUPP;
+ } else if (!attr->exclude_hv) {
+ return -EOPNOTSUPP;
+ }
+
+ 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;
+}Please add below messaging such as to avoid users having to do so themselves:
diff --git a/drivers/perf/arm_spe_pmu.c b/drivers/perf/arm_spe_pmu.c
index b4906c3..7c2635c 100644
--- a/drivers/perf/arm_spe_pmu.c
+++ b/drivers/perf/arm_spe_pmu.c@@ -655,24 +655,33 @@ 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); + struct device *dev = &spe_pmu->pdev->dev; /* 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)) + !cpumask_test_cpu(event->cpu, &spe_pmu->supported_cpus)) { + dev_err_ratelimited(dev, "CPU not supported by SPE\n"); return -ENOENT; + } - if (arm_spe_event_to_pmsevfr(event) & PMSEVFR_EL1_RES0) + if (arm_spe_event_to_pmsevfr(event) & PMSEVFR_EL1_RES0) { + dev_err_ratelimited(dev, "Unsupported event filter\n"); return -EOPNOTSUPP; + } if (event->hw.sample_period < spe_pmu->min_period || - event->hw.sample_period & PMSIRR_EL1_IVAL_MASK) + event->hw.sample_period & PMSIRR_EL1_IVAL_MASK) { + dev_err_ratelimited(dev, "Cannot set sample period below the minimum interval\n"); return -EOPNOTSUPP; + } - if (attr->exclude_idle) + if (attr->exclude_idle) { + dev_err_ratelimited(dev, "Cannot exclude profiling when idle\n"); return -EOPNOTSUPP; + } /* * Feedback-directed frequency throttling doesn't work when we
@@ -681,28 +690,39 @@ static int arm_spe_pmu_event_init(struct perf_event *event) * count to reflect that. Instead, force the user to specify a * sample period instead. */ - if (attr->freq) + if (attr->freq) { + dev_err_ratelimited(dev, "a sample period must be specified\n"); return -EINVAL; + } if (is_kernel_in_hyp_mode()) { - if (attr->exclude_kernel != attr->exclude_hv) + if (attr->exclude_kernel != attr->exclude_hv) { + dev_err_ratelimited(dev, "VHE is enabled but exclude_kernel and exclude_hv do not match\n"); return -EOPNOTSUPP; + } } else if (!attr->exclude_hv) { + dev_err_ratelimited(dev, "VHE is disabled but exclude_hv is not set\n"); return -EOPNOTSUPP; } reg = arm_spe_event_to_pmsfcr(event); if ((reg & BIT(PMSFCR_EL1_FE_SHIFT)) && - !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT)) + !(spe_pmu->features & SPE_PMU_FEAT_FILT_EVT)) { + dev_err_ratelimited(dev, "event filter feature not supported\n"); return -EOPNOTSUPP; + } if ((reg & BIT(PMSFCR_EL1_FT_SHIFT)) && - !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP)) + !(spe_pmu->features & SPE_PMU_FEAT_FILT_TYP)) { + dev_err_ratelimited(dev, "event type filter feature not supported\n"); return -EOPNOTSUPP; + } if ((reg & BIT(PMSFCR_EL1_FL_SHIFT)) && - !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT)) + !(spe_pmu->features & SPE_PMU_FEAT_FILT_LAT)) { + dev_err_ratelimited(dev, "latency filter feature not supported\n"); return -EOPNOTSUPP; + } return 0; }
Thanks, Kim