Messages in this thread | | | From | Anshuman Khandual <> | Subject | Re: [RFC V1 05/11] arm64/perf: Detect support for BRBE | Date | Fri, 28 Jan 2022 08:57:06 +0530 |
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On 1/26/22 10:48 PM, Rob Herring wrote: > On Mon, Jan 24, 2022 at 10:00:47AM +0530, Anshuman Khandual wrote: >> CPU specific BRBE entries, cycle count, format support gets detected during >> PMU init. This information gets saved in per-cpu struct pmu_hw_events which >> later helps in operating BRBE during a perf event context. > > Another NOP commit. The subject says 'arm64' and that we detect BRBE > support. This patch neither touches arm64 code nor detects anything.
Right, this is a NOP at this point but it will have functionality when the driver gets added later on. I will correct the arm64 part and also update the message saying - it just adds the infrastructure for BRBE detection not the actual function.
> >> >> Cc: Will Deacon <will@kernel.org> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> >> --- >> drivers/perf/arm_pmu_platform.c | 34 +++++++++++++++++++++++++++++++++ >> 1 file changed, 34 insertions(+) >> >> diff --git a/drivers/perf/arm_pmu_platform.c b/drivers/perf/arm_pmu_platform.c >> index 513de1f54e2d..800e4a6e8bc3 100644 >> --- a/drivers/perf/arm_pmu_platform.c >> +++ b/drivers/perf/arm_pmu_platform.c >> @@ -172,6 +172,36 @@ static int armpmu_request_irqs(struct arm_pmu *armpmu) >> return err; >> } >> >> +static void arm_brbe_probe_cpu(void *info) >> +{ >> + struct pmu_hw_events *hw_events; >> + struct arm_pmu *armpmu = info; >> + >> + /* >> + * Return from here, if BRBE driver has not been >> + * implemented for this PMU. This helps prevent >> + * kernel crash later when brbe_probe() will be >> + * called on the PMU. >> + */ >> + if (!armpmu->brbe_probe) >> + return; >> + >> + hw_events = per_cpu_ptr(armpmu->hw_events, smp_processor_id()); >> + armpmu->brbe_probe(hw_events); >> +} >> + >> +static int armpmu_request_brbe(struct arm_pmu *armpmu) >> +{ >> + int cpu, err = 0; >> + >> + for_each_cpu(cpu, &armpmu->supported_cpus) { >> + err = smp_call_function_single(cpu, arm_brbe_probe_cpu, armpmu, 1); >> + if (err) >> + return err; >> + } >> + return err; >> +} >> + >> static void armpmu_free_irqs(struct arm_pmu *armpmu) >> { >> int cpu; >> @@ -229,6 +259,10 @@ int arm_pmu_device_probe(struct platform_device *pdev, >> if (ret) >> goto out_free_irqs; >> >> + ret = armpmu_request_brbe(pmu); >> + if (ret) >> + goto out_free_irqs; >> + >> ret = armpmu_register(pmu); >> if (ret) { >> dev_err(dev, "failed to register PMU devices!\n"); >> -- >> 2.25.1 >> >>
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