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Date: Wed, 17 Jun 2020 12:38:51 +0100 From: Alexandru Elisei <alexandru.elisei@....com> To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org Cc: maz@...nel.org, will@...nel.org, catalin.marinas@....com, mark.rutland@....com, Julien Thierry <julien.thierry@....com>, Julien Thierry <julien.thierry.kdev@...il.com>, Will Deacon <will.deacon@....com> Subject: [PATCH v5 7/7] arm_pmu: arm64: Use NMIs for PMU From: Julien Thierry <julien.thierry@....com> Add required PMU interrupt operations for NMIs. Request interrupt lines as NMIs when possible, otherwise fall back to normal interrupts. NMIs are only supported on the arm64 architecture with a GICv3 irqchip. Cc: Julien Thierry <julien.thierry.kdev@...il.com> Cc: Will Deacon <will.deacon@....com> Cc: Mark Rutland <mark.rutland@....com> Signed-off-by: Julien Thierry <julien.thierry@....com> [Added that NMIs only work on arm64 + GICv3] Signed-off-by: Alexandru Elisei <alexandru.elisei@....com> --- drivers/perf/arm_pmu.c | 62 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 56 insertions(+), 6 deletions(-) diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 17e5952d21e4..dd9d7f61ee29 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -45,6 +45,17 @@ static const struct pmu_irq_ops pmuirq_ops = { .free_pmuirq = armpmu_free_pmuirq }; +static void armpmu_free_pmunmi(unsigned int irq, int cpu, void __percpu *devid) +{ + free_nmi(irq, per_cpu_ptr(devid, cpu)); +} + +static const struct pmu_irq_ops pmunmi_ops = { + .enable_pmuirq = enable_nmi, + .disable_pmuirq = disable_nmi_nosync, + .free_pmuirq = armpmu_free_pmunmi +}; + static void armpmu_enable_percpu_pmuirq(unsigned int irq) { enable_percpu_irq(irq, IRQ_TYPE_NONE); @@ -63,6 +74,31 @@ static const struct pmu_irq_ops percpu_pmuirq_ops = { .free_pmuirq = armpmu_free_percpu_pmuirq }; +static void armpmu_enable_percpu_pmunmi(unsigned int irq) +{ + if (!prepare_percpu_nmi(irq)) + enable_percpu_nmi(irq, IRQ_TYPE_NONE); +} + +static void armpmu_disable_percpu_pmunmi(unsigned int irq) +{ + disable_percpu_nmi(irq); + teardown_percpu_nmi(irq); +} + +static void armpmu_free_percpu_pmunmi(unsigned int irq, int cpu, + void __percpu *devid) +{ + if (armpmu_count_irq_users(irq) == 1) + free_percpu_nmi(irq, devid); +} + +static const struct pmu_irq_ops percpu_pmunmi_ops = { + .enable_pmuirq = armpmu_enable_percpu_pmunmi, + .disable_pmuirq = armpmu_disable_percpu_pmunmi, + .free_pmuirq = armpmu_free_percpu_pmunmi +}; + static DEFINE_PER_CPU(struct arm_pmu *, cpu_armpmu); static DEFINE_PER_CPU(int, cpu_irq); static DEFINE_PER_CPU(const struct pmu_irq_ops *, cpu_irq_ops); @@ -633,15 +669,29 @@ int armpmu_request_irq(int irq, int cpu) IRQF_NO_THREAD; irq_set_status_flags(irq, IRQ_NOAUTOEN); - err = request_irq(irq, handler, irq_flags, "arm-pmu", + + err = request_nmi(irq, handler, irq_flags, "arm-pmu", per_cpu_ptr(&cpu_armpmu, cpu)); - irq_ops = &pmuirq_ops; + /* If cannot get an NMI, get a normal interrupt */ + if (err) { + err = request_irq(irq, handler, irq_flags, "arm-pmu", + per_cpu_ptr(&cpu_armpmu, cpu)); + irq_ops = &pmuirq_ops; + } else { + irq_ops = &pmunmi_ops; + } } else if (armpmu_count_irq_users(irq) == 0) { - err = request_percpu_irq(irq, handler, "arm-pmu", - &cpu_armpmu); - - irq_ops = &percpu_pmuirq_ops; + err = request_percpu_nmi(irq, handler, "arm-pmu", &cpu_armpmu); + + /* If cannot get an NMI, get a normal interrupt */ + if (err) { + err = request_percpu_irq(irq, handler, "arm-pmu", + &cpu_armpmu); + irq_ops = &percpu_pmuirq_ops; + } else { + irq_ops = &percpu_pmunmi_ops; + } } else { /* Per cpudevid irq was already requested by another CPU */ irq_ops = armpmu_find_irq_ops(irq); -- 2.27.0
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