[PATCH v6 3/4] genirq: Provide NMI handlers

From: Julien Thierry
Date: Thu Jan 31 2019 - 09:54:34 EST


Provide flow handlers that are NMI safe for interrupts and percpu_devid
interrupts.

Signed-off-by: Julien Thierry <julien.thierry@xxxxxxx>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
---
include/linux/irq.h | 3 +++
kernel/irq/chip.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 57 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index a7298e4..5e91f6b 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -601,6 +601,9 @@ static inline int irq_set_parent(int irq, int parent_irq)
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 int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg);
extern int irq_chip_pm_get(struct irq_data *data);
extern int irq_chip_pm_put(struct irq_data *data);
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 34e9690..c32d5f3 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -730,6 +730,37 @@ void handle_fasteoi_irq(struct irq_desc *desc)
EXPORT_SYMBOL_GPL(handle_fasteoi_irq);

/**
+ * handle_fasteoi_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.
+ */
+void handle_fasteoi_nmi(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct irqaction *action = desc->action;
+ unsigned int irq = irq_desc_get_irq(desc);
+ irqreturn_t res;
+
+ trace_irq_handler_entry(irq, action);
+ /*
+ * NMIs cannot be shared, there is only one action.
+ */
+ res = action->handler(irq, action->dev_id);
+ trace_irq_handler_exit(irq, action, res);
+
+ if (chip->irq_eoi)
+ chip->irq_eoi(&desc->irq_data);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_nmi);
+
+/**
* handle_edge_irq - edge type IRQ handler
* @desc: the interrupt description structure for this irq
*
@@ -908,6 +939,29 @@ void handle_percpu_devid_irq(struct irq_desc *desc)
chip->irq_eoi(&desc->irq_data);
}

+/**
+ * handle_percpu_devid_fasteoi_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.
+ */
+void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct irqaction *action = desc->action;
+ unsigned int irq = irq_desc_get_irq(desc);
+ irqreturn_t res;
+
+ trace_irq_handler_entry(irq, action);
+ res = action->handler(irq, raw_cpu_ptr(action->percpu_dev_id));
+ trace_irq_handler_exit(irq, action, res);
+
+ if (chip->irq_eoi)
+ chip->irq_eoi(&desc->irq_data);
+}
+
static void
__irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
int is_chained, const char *name)
--
1.9.1