Subject: [PATCH 2/2] arm64: perf: add support for percpu pmu interrupt

From: [email-masked] (Stephen Boyd)
Date: Fri, 08 Nov 2013 17:04:27 -0800

Just some pointer casting nits.

On 11/06/13 04:07, Vinayak Kale wrote:
> Add support for irq registration when pmu interrupt is percpu.
>
> Signed-off-by: Vinayak Kale <[email-masked]>
> Signed-off-by: Tuan Phan <[email-masked]>
> ---
>  arch/arm64/kernel/perf_event.c |  109 +++++++++++++++++++++++++++++-----------
>  1 file changed, 81 insertions(+), 28 deletions(-)
>
> diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> index cea1594..e60dae3 100644
> --- a/arch/arm64/kernel/perf_event.c
> +++ b/arch/arm64/kernel/perf_event.c
> @@ -44,6 +44,7 @@
>  static DEFINE_PER_CPU(struct perf_event * [ARMPMU_MAX_HWEVENTS], hw_events);
>  static DEFINE_PER_CPU(unsigned long [BITS_TO_LONGS(ARMPMU_MAX_HWEVENTS)], used_mask);
>  static DEFINE_PER_CPU(struct pmu_hw_events, cpu_hw_events);
> +static bool is_percpuirq;
>  
>  #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
>  
> @@ -363,22 +364,51 @@ validate_group(struct perf_event *event)
>  }
>  
>  static void
> +armpmu_disable_percpu_irq(void *data)
> +{
> +	struct arm_pmu *armpmu = (struct arm_pmu *)data;

Useless cast from void *.

> +	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_enable_percpu_irq(void *data)
> +{
> +	struct arm_pmu *armpmu = (struct arm_pmu *)data;

Here too.

> +	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 +426,57 @@ 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 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;
> -		}
> +	/*
> +	 * Try 'request_percpu_irq' first. If it's return value indicates
> +	 * that irq is not percpu then try 'request_irq'
> +	 */
> +	err = request_percpu_irq(irq, armpmu->handle_irq,
> +			"arm-pmu", &cpu_hw_events);
> +	if (err != -EPERM) {
> +		is_percpuirq = true;
>  
> -		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, (void *)armpmu, 1);

Looks like a useless cast to void * here.

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