Jeremy Linton <jeremy.linton@xxxxxxx> writes:
> On systems with multiple PMU types the PMU to CPU affinity
> needs to be detected and set. The CPU to interrupt affinity
> should also be set.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> ---
> drivers/perf/arm_pmu.c | 53 ++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 43 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
> index f1aee26..ee9e301 100644
> --- a/drivers/perf/arm_pmu.c
> +++ b/drivers/perf/arm_pmu.c
[...]
> @@ -876,25 +878,57 @@ static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
> }
>
> /*
> - * CPU PMU identification and probing.
> + * CPU PMU identification and probing. Its possible to have
> + * multiple CPU types in an ARM machine. Assure that we are
> + * picking the right PMU types based on the CPU in question
> */
> -static int probe_current_pmu(struct arm_pmu *pmu,
> - const struct pmu_probe_info *info)
> +static int probe_plat_pmu(struct arm_pmu *pmu,
> + const struct pmu_probe_info *info,
> + unsigned int pmuid)
> {
> - int cpu = get_cpu();
> - unsigned int cpuid = read_cpuid_id();
> int ret = -ENODEV;
> + int cpu;
> + int aff_ctr = 0;
> + static int duplicate_pmus;
> + struct platform_device *pdev = pmu->plat_device;
> + int irq = platform_get_irq(pdev, 0);
> +
> + if (irq >= 0 && !irq_is_percpu(irq)) {
> + pmu->irq_affinity = kcalloc(pdev->num_resources, sizeof(int),
> + GFP_KERNEL);
> + if (!pmu->irq_affinity)
> + return -ENOMEM;
> + }
>
> - pr_info("probing PMU on CPU %d\n", cpu);
> + for_each_possible_cpu(cpu) {
> + unsigned int cpuid = read_specific_cpuid(cpu);
>
> + if (cpuid == pmuid) {
> + cpumask_set_cpu(cpu, &pmu->supported_cpus);
> + if (pmu->irq_affinity) {
> + pmu->irq_affinity[aff_ctr] = cpu;
> + aff_ctr++;
> + }
> + }
> + }
> +
> + /* find the type of PMU given the CPU */
> for (; info->init != NULL; info++) {
> - if ((cpuid & info->mask) != info->cpuid)
> + if ((pmuid & info->mask) != info->cpuid)
> continue;
> ret = info->init(pmu);
> + if ((!info->cpuid) && (duplicate_pmus)) {
It's not obvious what the condition "!info->cpuid" implies. Please add a
comment explaining the rationale.
Also, the parenthesis around the two parts of the logical operation can
be dropped.
> + pmu->name = kasprintf(GFP_KERNEL, "%s_%d",
> + pmu->name, duplicate_pmus);
> + if (!pmu->name) {
> + kfree(pmu->irq_affinity);
> + ret = -ENOMEM;
> + }
> + }
> + duplicate_pmus++;
> break;
> }
>
> - put_cpu();
> return ret;
> }
>
[...]
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