linux-kernel - [PATCH 14/25] genirq: Update request_percpu

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Message-Id: <20250908163127.2462948-15-maz@kernel.org>
Date: Mon,  8 Sep 2025 17:31:16 +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 14/25] genirq: Update request_percpu_nmi() to take an affinity

Continue spreading the notion of affinity to the percpu interrupt
request code by updating the call sites that use request_percpu_nmi()
(all two of them) to take an affinity pointer. This pointer is
firmly NULL for now.

Signed-off-by: Marc Zyngier <maz@...nel.org>
---
 arch/arm64/kernel/smp.c   |  2 +-
 drivers/perf/arm_pmu.c    |  4 +++-
 include/linux/interrupt.h |  4 ++--
 kernel/irq/manage.c       | 11 +++++++----
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 68cea3a4a35ca..6fb838eee2e7d 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -1094,7 +1094,7 @@ static void ipi_setup_sgi(int ipi)
 	irq = ipi_irq_base + ipi;
 
 	if (ipi_should_be_nmi(ipi)) {
-		err = request_percpu_nmi(irq, ipi_handler, "IPI", &irq_stat);
+		err = request_percpu_nmi(irq, ipi_handler, "IPI", NULL, &irq_stat);
 		WARN(err, "Could not request IRQ %d as NMI, err=%d\n", irq, err);
 	} else {
 		err = request_percpu_irq(irq, ipi_handler, "IPI", &irq_stat);
diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 6e3c72e9b41cd..d1f738eb77f1e 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -678,7 +678,9 @@ int armpmu_request_irq(int irq, int cpu)
 			irq_ops = &pmunmi_ops;
 		}
 	} else if (armpmu_count_irq_users(cpu, irq) == 0) {
-		err = request_percpu_nmi(irq, handler, "arm-pmu", &cpu_armpmu);
+		err = request_percpu_nmi(irq, handler, "arm-pmu",
+					 NULL,
+					 &cpu_armpmu);
 
 		/* If cannot get an NMI, get a normal interrupt */
 		if (err) {
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 52147d5f432b3..2134e7c08c169 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -197,8 +197,8 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler,
 }
 
 extern int __must_check
-request_percpu_nmi(unsigned int irq, irq_handler_t handler,
-		   const char *devname, void __percpu *dev);
+request_percpu_nmi(unsigned int irq, irq_handler_t handler, const char *devname,
+		   const struct cpumask *affinity, void __percpu *dev_id);
 
 extern const void *free_irq(unsigned int, void *);
 extern void free_percpu_irq(unsigned int, void __percpu *);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index ac394f0b422b8..a17ac522622e7 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -2530,6 +2530,7 @@ EXPORT_SYMBOL_GPL(__request_percpu_irq);
  * @irq:	Interrupt line to allocate
  * @handler:	Function to be called when the IRQ occurs.
  * @name:	An ascii name for the claiming device
+ * @affinity:	A cpumask describing the target CPUs for this interrupt
  * @dev_id:	A percpu cookie passed back to the handler function
  *
  * This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs
@@ -2547,7 +2548,8 @@ EXPORT_SYMBOL_GPL(__request_percpu_irq);
  * will fail returning a negative value.
  */
 int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
-		       const char *name, void __percpu *dev_id)
+		       const char *name,
+		       const struct cpumask *affinity, void __percpu *dev_id)
 {
 	struct irqaction *action;
 	struct irq_desc *desc;
@@ -2564,13 +2566,14 @@ int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
 	    !irq_supports_nmi(desc))
 		return -EINVAL;
 
-	/* The line cannot already be NMI */
-	if (irq_is_nmi(desc))
+	/* The line cannot be NMI already if the new request covers all CPUs */
+	if (irq_is_nmi(desc) &&
+	    (!affinity || cpumask_equal(affinity, cpu_possible_mask)))
 		return -EINVAL;
 
 	action = create_percpu_irqaction(handler,
 					 IRQF_NO_THREAD | IRQF_NOBALANCING,
-					 name, NULL, dev_id);
+					 name, affinity, dev_id);
 	if (!action)
 		return -ENOMEM;
 
-- 
2.39.2