linux-kernel - [PATCH 17/25] perf: arm_pmu: Use a backend-specific pointer for percpu interrupt request

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Message-Id: <20250908163127.2462948-18-maz@kernel.org>
Date: Mon,  8 Sep 2025 17:31:19 +0100
From: Marc Zyngier <maz@...nel.org>
To: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-acpi@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
	Mark Rutland <mark.rutland@....com>,
	Will Deacon <will@...nel.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Rob Herring <robh@...nel.org>,
	Saravana Kannan <saravanak@...gle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Sven Peter <sven@...nel.org>,
	Janne Grunau <j@...nau.net>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	James Clark <james.clark@...aro.org>
Subject: [PATCH 17/25] perf: arm_pmu: Use a backend-specific pointer for percpu interrupt request

From: Will Deacon <will@...nel.org>

DT and ACPI significantly differ in the way the PMU probing is
conducted, resulting in different data being available at different
times.

Work around this by providing a per-cpu 'struct arm_pmu *' as
a parameter, instead of sampling it from a per-cpu variable.

Signed-off-by: Will Deacon <will@...nel.org>
Signed-off-by: Marc Zyngier <maz@...nel.org>
---
 drivers/perf/arm_pmu.c          | 10 +++++-----
 drivers/perf/arm_pmu_acpi.c     |  2 +-
 drivers/perf/arm_pmu_platform.c |  4 ++--
 include/linux/perf/arm_pmu.h    |  4 ++--
 4 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index d1f738eb77f1e..044c9c6296997 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -628,20 +628,20 @@ static const struct pmu_irq_ops *armpmu_find_irq_ops(int this_cpu, int irq)
 	return ops;
 }
 
-void armpmu_free_irq(int irq, int cpu)
+void armpmu_free_irq(struct arm_pmu * __percpu *armpmu, int irq, int cpu)
 {
 	if (per_cpu(cpu_irq, cpu) == 0)
 		return;
 	if (WARN_ON(irq != per_cpu(cpu_irq, cpu)))
 		return;
 
-	per_cpu(cpu_irq_ops, cpu)->free_pmuirq(irq, cpu, &cpu_armpmu);
+	per_cpu(cpu_irq_ops, cpu)->free_pmuirq(irq, cpu, armpmu);
 
 	per_cpu(cpu_irq, cpu) = 0;
 	per_cpu(cpu_irq_ops, cpu) = NULL;
 }
 
-int armpmu_request_irq(int irq, int cpu)
+int armpmu_request_irq(struct arm_pmu * __percpu *armpmu, int irq, int cpu)
 {
 	int err = 0;
 	const irq_handler_t handler = armpmu_dispatch_irq;
@@ -666,12 +666,12 @@ int armpmu_request_irq(int irq, int cpu)
 			    IRQF_NO_THREAD;
 
 		err = request_nmi(irq, handler, irq_flags, "arm-pmu",
-				  per_cpu_ptr(&cpu_armpmu, cpu));
+				  per_cpu_ptr(armpmu, cpu));
 
 		/* 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));
+					  per_cpu_ptr(armpmu, cpu));
 			irq_ops = &pmuirq_ops;
 		} else {
 			has_nmi = true;
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index a5956fa728070..a28352e2bff0a 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -223,7 +223,7 @@ static int arm_pmu_acpi_parse_irqs(void)
 		 * them with their PMUs.
 		 */
 		per_cpu(pmu_irqs, cpu) = irq;
-		err = armpmu_request_irq(irq, cpu);
+		err = armpmu_request_irq(&probed_pmus, irq, cpu);
 		if (err)
 			goto out_err;
 	}
diff --git a/drivers/perf/arm_pmu_platform.c b/drivers/perf/arm_pmu_platform.c
index 0c7d5065e9074..d9b0e8f6debf2 100644
--- a/drivers/perf/arm_pmu_platform.c
+++ b/drivers/perf/arm_pmu_platform.c
@@ -169,7 +169,7 @@ static int armpmu_request_irqs(struct arm_pmu *armpmu)
 		if (!irq)
 			continue;
 
-		err = armpmu_request_irq(irq, cpu);
+		err = armpmu_request_irq(&hw_events->percpu_pmu, irq, cpu);
 		if (err)
 			break;
 	}
@@ -185,7 +185,7 @@ static void armpmu_free_irqs(struct arm_pmu *armpmu)
 	for_each_cpu(cpu, &armpmu->supported_cpus) {
 		int irq = per_cpu(hw_events->irq, cpu);
 
-		armpmu_free_irq(irq, cpu);
+		armpmu_free_irq(&hw_events->percpu_pmu, irq, cpu);
 	}
 }
 
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 7bf548678b288..395d03c282e8c 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -191,8 +191,8 @@ bool arm_pmu_irq_is_nmi(void);
 struct arm_pmu *armpmu_alloc(void);
 void armpmu_free(struct arm_pmu *pmu);
 int armpmu_register(struct arm_pmu *pmu);
-int armpmu_request_irq(int irq, int cpu);
-void armpmu_free_irq(int irq, int cpu);
+int armpmu_request_irq(struct arm_pmu * __percpu *armpmu, int irq, int cpu);
+void armpmu_free_irq(struct arm_pmu * __percpu *armpmu, int irq, int cpu);
 
 #define ARMV8_PMU_PDEV_NAME "armv8-pmu"
 
-- 
2.39.2