[PATCH v4 15/26] genirq: Update request_percpu_nmi() to take an affinity

Marc Zyngier posted 26 patches 1 month, 3 weeks ago
[PATCH v4 15/26] genirq: Update request_percpu_nmi() to take an affinity
Posted by Marc Zyngier 1 month, 3 weeks ago
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.

Tested-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kernel/smp.c   |  2 +-
 drivers/perf/arm_pmu.c    |  2 +-
 include/linux/interrupt.h |  4 ++--
 kernel/irq/manage.c       | 12 +++++++-----
 4 files changed, 11 insertions(+), 9 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 5c310e803dd78..22c601b46c858 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -659,7 +659,7 @@ int armpmu_request_irq(int irq, int cpu)
 			irq_ops = &pmunmi_ops;
 		}
 	} else if (armpmu_count_irq_users(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..81506ab759b81 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 *name,
+		   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 5f4c651677436..b1a3140e5f3c9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -2527,6 +2527,7 @@ 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
@@ -2543,8 +2544,8 @@ EXPORT_SYMBOL_GPL(__request_percpu_irq);
  * If the interrupt line cannot be used to deliver NMIs, function
  * will fail returning a negative value.
  */
-int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
-		       const char *name, void __percpu *dev_id)
+int request_percpu_nmi(unsigned int irq, irq_handler_t handler, const char *name,
+		       const struct cpumask *affinity, void __percpu *dev_id)
 {
 	struct irqaction *action;
 	struct irq_desc *desc;
@@ -2561,12 +2562,13 @@ 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;
 
-- 
2.47.3
Re: [PATCH v4 15/26] genirq: Update request_percpu_nmi() to take an affinity
Posted by Jonathan Cameron 1 month ago
On Mon, 20 Oct 2025 13:29:32 +0100
Marc Zyngier <maz@kernel.org> wrote:

> 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.
> 
> Tested-by: Will Deacon <will@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
[tip: irq/core] genirq: Update request_percpu_nmi() to take an affinity
Posted by tip-bot2 for Marc Zyngier 1 month, 2 weeks ago
The following commit has been merged into the irq/core branch of tip:

Commit-ID:     b9c6aa9efc71dae656f9f913d1250ea08cd6e10f
Gitweb:        https://git.kernel.org/tip/b9c6aa9efc71dae656f9f913d1250ea08cd6e10f
Author:        Marc Zyngier <maz@kernel.org>
AuthorDate:    Mon, 20 Oct 2025 13:29:32 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 27 Oct 2025 17:16:35 +01:00

genirq: Update request_percpu_nmi() to take an affinity

Continue spreading the notion of affinity to the per CPU 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@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20251020122944.3074811-16-maz@kernel.org
---
 arch/arm64/kernel/smp.c   |  2 +-
 drivers/perf/arm_pmu.c    |  2 +-
 include/linux/interrupt.h |  4 ++--
 kernel/irq/manage.c       | 12 +++++++-----
 4 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 68cea3a..6fb838e 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 5c310e8..22c601b 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -659,7 +659,7 @@ int armpmu_request_irq(int irq, int cpu)
 			irq_ops = &pmunmi_ops;
 		}
 	} else if (armpmu_count_irq_users(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 52147d5..81506ab 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 *name,
+		   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 5f4c651..b1a3140 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -2527,6 +2527,7 @@ 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
@@ -2543,8 +2544,8 @@ EXPORT_SYMBOL_GPL(__request_percpu_irq);
  * If the interrupt line cannot be used to deliver NMIs, function
  * will fail returning a negative value.
  */
-int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
-		       const char *name, void __percpu *dev_id)
+int request_percpu_nmi(unsigned int irq, irq_handler_t handler, const char *name,
+		       const struct cpumask *affinity, void __percpu *dev_id)
 {
 	struct irqaction *action;
 	struct irq_desc *desc;
@@ -2561,12 +2562,13 @@ 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;