linux-kernel - [RFC PATCH v2 07/10] genirq, irq-gic-v3: Make NMI flow handlers use ->irq

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Message-Id: <20210525173255.620606-8-valentin.schneider@arm.com>
Date:   Tue, 25 May 2021 18:32:52 +0100
From:   Valentin Schneider <valentin.schneider@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     Marc Zyngier <maz@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Vincenzo Frascino <vincenzo.frascino@....com>
Subject: [RFC PATCH v2 07/10] genirq, irq-gic-v3: Make NMI flow handlers use ->irq_ack() if available

Subsequent patches will make the gic-v3 irqchip use an ->irq_ack()
callback. As a preparation, make the NMI flow handlers call said callback
if it is available.

Since this departs from the fasteoi scheme of only issuing a suffix
->eoi(), rename the NMI flow handlers.

Signed-off-by: Valentin Schneider <valentin.schneider@....com>
---
 drivers/irqchip/irq-gic-v3.c |  4 ++--
 include/linux/irq.h          |  4 ++--
 kernel/irq/chip.c            | 25 ++++++++++++++-----------
 3 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 37a23aa6de37..af11396996e3 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -484,10 +484,10 @@ static int gic_irq_nmi_setup(struct irq_data *d)
 		/* Setting up PPI as NMI, only switch handler for first NMI */
 		if (!refcount_inc_not_zero(&ppi_nmi_refs[idx])) {
 			refcount_set(&ppi_nmi_refs[idx], 1);
-			desc->handle_irq = handle_percpu_devid_fasteoi_nmi;
+			desc->handle_irq = handle_percpu_devid_nmi;
 		}
 	} else {
-		desc->handle_irq = handle_fasteoi_nmi;
+		desc->handle_irq = handle_nmi;
 	}
 
 	gic_irq_set_prio(d, GICD_INT_NMI_PRI);
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 37075929e329..0b45e42812d6 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -669,8 +669,8 @@ extern void handle_percpu_devid_irq(struct irq_desc *desc);
 extern void handle_bad_irq(struct irq_desc *desc);
 extern void handle_nested_irq(unsigned int irq);
 
-extern void handle_fasteoi_nmi(struct irq_desc *desc);
-extern void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc);
+extern void handle_nmi(struct irq_desc *desc);
+extern void handle_percpu_devid_nmi(struct irq_desc *desc);
 
 extern int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg);
 extern int irq_chip_pm_get(struct irq_data *data);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index c2ca6b748987..099bc7e13d1b 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -748,18 +748,16 @@ void handle_fasteoi_irq(struct irq_desc *desc)
 EXPORT_SYMBOL_GPL(handle_fasteoi_irq);
 
 /**
- *	handle_fasteoi_nmi - irq handler for NMI interrupt lines
+ *	handle_nmi - irq handler for NMI interrupt lines
  *	@desc:	the interrupt description structure for this irq
  *
  *	A simple NMI-safe handler, considering the restrictions
  *	from request_nmi.
  *
- *	Only a single callback will be issued to the chip: an ->eoi()
- *	call when the interrupt has been serviced. This enables support
- *	for modern forms of interrupt handlers, which handle the flow
- *	details in hardware, transparently.
+ *      An ->ack() callback will be issued before servicing the interrupt,
+ *      followed by an ->eoi() call.
  */
-void handle_fasteoi_nmi(struct irq_desc *desc)
+void handle_nmi(struct irq_desc *desc)
 {
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	struct irqaction *action = desc->action;
@@ -768,6 +766,9 @@ void handle_fasteoi_nmi(struct irq_desc *desc)
 
 	__kstat_incr_irqs_this_cpu(desc);
 
+	if (chip->irq_ack)
+		chip->irq_ack(&desc->irq_data);
+
 	trace_irq_handler_entry(irq, action);
 	/*
 	 * NMIs cannot be shared, there is only one action.
@@ -778,7 +779,7 @@ void handle_fasteoi_nmi(struct irq_desc *desc)
 	if (chip->irq_eoi)
 		chip->irq_eoi(&desc->irq_data);
 }
-EXPORT_SYMBOL_GPL(handle_fasteoi_nmi);
+EXPORT_SYMBOL_GPL(handle_nmi);
 
 /**
  *	handle_edge_irq - edge type IRQ handler
@@ -1032,14 +1033,13 @@ void handle_percpu_devid_irq(struct irq_desc *desc)
 }
 
 /**
- * handle_percpu_devid_fasteoi_nmi - Per CPU local NMI handler with per cpu
+ * handle_percpu_devid_nmi - Per CPU local NMI handler with per cpu
  *				     dev ids
  * @desc:	the interrupt description structure for this irq
  *
- * Similar to handle_fasteoi_nmi, but handling the dev_id cookie
- * as a percpu pointer.
+ * Similar to handle_nmi, but handling the dev_id cookie as a percpu pointer.
  */
-void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc)
+void handle_percpu_devid_nmi(struct irq_desc *desc)
 {
 	struct irq_chip *chip = irq_desc_get_chip(desc);
 	struct irqaction *action = desc->action;
@@ -1048,6 +1048,9 @@ void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc)
 
 	__kstat_incr_irqs_this_cpu(desc);
 
+	if (chip->irq_ack)
+		chip->irq_ack(&desc->irq_data);
+
 	trace_irq_handler_entry(irq, action);
 	res = action->handler(irq, raw_cpu_ptr(action->percpu_dev_id));
 	trace_irq_handler_exit(irq, action, res);
-- 
2.25.1