Hi Marc, On Wed, Nov 20, 2013 at 6:44 PM, Marc Zyngier <marc.zyng...@arm.com> wrote: > [dropped patc...@apm.com] > > Vinayak, > > Please keep reviewers on CC, as it makes easier to track the changes. Sure, will do. > > On 20/11/13 11:13, Vinayak Kale wrote: >> Add support for irq registration when pmu interrupt is percpu. >> >> Signed-off-by: Vinayak Kale <vk...@apm.com> >> Signed-off-by: Tuan Phan <tp...@apm.com> >> --- >> arch/arm64/kernel/perf_event.c | 108 >> ++++++++++++++++++++++++++++++---------- >> 1 file changed, 81 insertions(+), 27 deletions(-) >> >> diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c >> index cea1594..de12ba8 100644 >> --- a/arch/arm64/kernel/perf_event.c >> +++ b/arch/arm64/kernel/perf_event.c >> @@ -22,6 +22,7 @@ >> >> #include <linux/bitmap.h> >> #include <linux/interrupt.h> >> +#include <linux/irq.h> >> #include <linux/kernel.h> >> #include <linux/export.h> >> #include <linux/perf_event.h> >> @@ -363,22 +364,55 @@ validate_group(struct perf_event *event) >> } >> >> static void >> +armpmu_disable_percpu_irq(void *data) >> +{ >> + struct arm_pmu *armpmu = data; >> + struct platform_device *pmu_device = armpmu->plat_device; >> + int irq = platform_get_irq(pmu_device, 0); >> + >> + cpumask_test_and_clear_cpu(smp_processor_id(), &armpmu->active_irqs); >> + disable_percpu_irq(irq); >> +} >> + >> +static void >> armpmu_release_hardware(struct arm_pmu *armpmu) >> { >> int i, irq, irqs; >> struct platform_device *pmu_device = armpmu->plat_device; >> >> irqs = min(pmu_device->num_resources, num_possible_cpus()); >> + if (irqs < 1) >> + return; >> >> - for (i = 0; i < irqs; ++i) { >> - if (!cpumask_test_and_clear_cpu(i, &armpmu->active_irqs)) >> - continue; >> - irq = platform_get_irq(pmu_device, i); >> - if (irq >= 0) >> - free_irq(irq, armpmu); >> + irq = platform_get_irq(pmu_device, 0); >> + if (irq < 0) > > So I'm going to sound like a stuck record: irq == 0 is not a valid IRQ > number, full stop. This is how we express the fact that there is no IRQ. > > If you're touching that code, you might as well fix this buglet. In Will's existing code, I think he was taking care of 'no IRQ' case by comparing pmu_device->num_resources. Do you think this is not enough and we must enforce the check after each platform_get_irq()? Existing driver code snippet as below for quick reference.
[snip] static int armpmu_reserve_hardware(struct arm_pmu *armpmu) { int i, err, irq, irqs; struct platform_device *pmu_device = armpmu->plat_device; if (!pmu_device) { pr_err("no PMU device registered\n"); return -ENODEV; } irqs = min(pmu_device->num_resources, num_possible_cpus()); if (irqs < 1) { pr_err("no irqs for PMUs defined\n"); return -ENODEV; } for (i = 0; i < irqs; ++i) { err = 0; irq = platform_get_irq(pmu_device, i); if (irq < 0) continue; [snip] > >> + return; >> + >> + if (irq_is_percpu(irq)) { >> + on_each_cpu(armpmu_disable_percpu_irq, armpmu, 1); >> + free_percpu_irq(irq, &cpu_hw_events); >> + } else { >> + for (i = 0; i < irqs; ++i) { >> + if (!cpumask_test_and_clear_cpu(i, >> &armpmu->active_irqs)) >> + continue; >> + irq = platform_get_irq(pmu_device, i); >> + if (irq >= 0) > > Same here. > >> + free_irq(irq, armpmu); >> + } >> } >> } >> >> +static void >> +armpmu_enable_percpu_irq(void *data) >> +{ >> + struct arm_pmu *armpmu = data; >> + struct platform_device *pmu_device = armpmu->plat_device; >> + int irq = platform_get_irq(pmu_device, 0); >> + >> + enable_percpu_irq(irq, 0); >> + cpumask_set_cpu(smp_processor_id(), &armpmu->active_irqs); >> +} >> + >> static int >> armpmu_reserve_hardware(struct arm_pmu *armpmu) >> { >> @@ -396,34 +430,54 @@ armpmu_reserve_hardware(struct arm_pmu *armpmu) >> return -ENODEV; >> } >> >> - for (i = 0; i < irqs; ++i) { >> - err = 0; >> - irq = platform_get_irq(pmu_device, i); >> - if (irq < 0) >> - continue; >> + irq = platform_get_irq(pmu_device, 0); >> + if (irq < 0) { > > And here. > >> + pr_err("failed to get an irq for PMU device\n"); >> + return -ENODEV; >> + } >> >> - /* >> - * If we have a single PMU interrupt that we can't shift, >> - * assume that we're running on a uniprocessor machine and >> - * continue. Otherwise, continue without this interrupt. >> - */ >> - if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) { >> - pr_warning("unable to set irq affinity (irq=%d, >> cpu=%u)\n", >> - irq, i); >> - continue; >> - } >> + if (irq_is_percpu(irq)) { >> + err = request_percpu_irq(irq, armpmu->handle_irq, >> + "arm-pmu", &cpu_hw_events); >> >> - err = request_irq(irq, armpmu->handle_irq, >> - IRQF_NOBALANCING, >> - "arm-pmu", armpmu); >> if (err) { >> - pr_err("unable to request IRQ%d for ARM PMU >> counters\n", >> - irq); >> + pr_err("unable to request percpu IRQ%d for ARM PMU >> counters\n", >> + irq); >> armpmu_release_hardware(armpmu); >> return err; >> } >> >> - cpumask_set_cpu(i, &armpmu->active_irqs); >> + on_each_cpu(armpmu_enable_percpu_irq, armpmu, 1); >> + } else { >> + for (i = 0; i < irqs; ++i) { >> + err = 0; >> + irq = platform_get_irq(pmu_device, i); >> + if (irq < 0) > > And here. > >> + continue; >> + >> + /* >> + * If we have a single PMU interrupt that we can't >> shift, >> + * assume that we're running on a uniprocessor machine >> and >> + * continue. Otherwise, continue without this >> interrupt. >> + */ >> + if (irq_set_affinity(irq, cpumask_of(i)) && irqs > 1) { >> + pr_warning("unable to set irq affinity >> (irq=%d, cpu=%u)\n", >> + irq, i); >> + continue; >> + } >> + >> + err = request_irq(irq, armpmu->handle_irq, >> + IRQF_NOBALANCING, >> + "arm-pmu", armpmu); >> + if (err) { >> + pr_err("unable to request IRQ%d for ARM PMU >> counters\n", >> + irq); >> + armpmu_release_hardware(armpmu); >> + return err; >> + } >> + >> + cpumask_set_cpu(i, &armpmu->active_irqs); >> + } >> } >> >> return 0; >> > > M. > -- > Jazz is not dead. It just smells funny... > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/