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authorWill Deacon <will.deacon@arm.com>2017-07-25 18:30:34 +0300
committerWill Deacon <will.deacon@arm.com>2017-07-27 15:43:22 +0300
commita3287c41ff405025bc57b165a0f6cd698bbbc1be (patch)
tree070b5f8986d50c1a2e72160871937f43f8c359f4 /drivers/perf
parentd0153c7ff9226535a51e6a81f61656c9500957f4 (diff)
downloadlinux-a3287c41ff405025bc57b165a0f6cd698bbbc1be.tar.xz
drivers/perf: arm_pmu: Request PMU SPIs with IRQF_PER_CPU
Since the PMU register interface is banked per CPU, CPU PMU interrrupts cannot be handled by a CPU other than the one with the PMU asserting the interrupt. This means that migrating PMU SPIs, as we do during a CPU hotplug operation doesn't make any sense and can lead to the IRQ being disabled entirely if we route a spurious IRQ to the new affinity target. This has been observed in practice on AMD Seattle, where CPUs on the non-boot cluster appear to take a spurious PMU IRQ when coming online, which is routed to CPU0 where it cannot be handled. This patch passes IRQF_PERCPU for PMU SPIs and forcefully sets their affinity prior to requesting them, ensuring that they cannot be migrated during hotplug events. This interacts badly with the DB8500 erratum workaround that ping-pongs the interrupt affinity from the handler, so we avoid passing IRQF_PERCPU in that case by allowing the IRQ flags to be overridden in the platdata. Fixes: 3cf7ee98b848 ("drivers/perf: arm_pmu: move irq request/free into probe") Cc: Mark Rutland <mark.rutland@arm.com> Cc: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'drivers/perf')
-rw-r--r--drivers/perf/arm_pmu.c41
1 files changed, 27 insertions, 14 deletions
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index dc459eb1246b..1c5e0f333779 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -569,22 +569,41 @@ int armpmu_request_irq(struct arm_pmu *armpmu, int cpu)
if (irq != other_irq) {
pr_warn("mismatched PPIs detected.\n");
err = -EINVAL;
+ goto err_out;
}
} else {
- err = request_irq(irq, handler,
- IRQF_NOBALANCING | IRQF_NO_THREAD, "arm-pmu",
+ struct arm_pmu_platdata *platdata = armpmu_get_platdata(armpmu);
+ unsigned long irq_flags;
+
+ err = irq_force_affinity(irq, cpumask_of(cpu));
+
+ if (err && num_possible_cpus() > 1) {
+ pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
+ irq, cpu);
+ goto err_out;
+ }
+
+ if (platdata && platdata->irq_flags) {
+ irq_flags = platdata->irq_flags;
+ } else {
+ irq_flags = IRQF_PERCPU |
+ IRQF_NOBALANCING |
+ IRQF_NO_THREAD;
+ }
+
+ err = request_irq(irq, handler, irq_flags, "arm-pmu",
per_cpu_ptr(&hw_events->percpu_pmu, cpu));
}
- if (err) {
- pr_err("unable to request IRQ%d for ARM PMU counters\n",
- irq);
- return err;
- }
+ if (err)
+ goto err_out;
cpumask_set_cpu(cpu, &armpmu->active_irqs);
-
return 0;
+
+err_out:
+ pr_err("unable to request IRQ%d for ARM PMU counters\n", irq);
+ return err;
}
int armpmu_request_irqs(struct arm_pmu *armpmu)
@@ -628,12 +647,6 @@ static int arm_perf_starting_cpu(unsigned int cpu, struct hlist_node *node)
enable_percpu_irq(irq, IRQ_TYPE_NONE);
return 0;
}
-
- if (irq_force_affinity(irq, cpumask_of(cpu)) &&
- num_possible_cpus() > 1) {
- pr_warn("unable to set irq affinity (irq=%d, cpu=%u)\n",
- irq, cpu);
- }
}
return 0;