Re: [PATCH 2/4] genirq: Provide NMI management for percpu_devid interrupts
From: Julien Thierry
Date: Wed Aug 01 2018 - 11:11:58 EST
On 01/08/18 04:11, Ricardo Neri wrote:
On Tue, Jul 24, 2018 at 12:07:05PM +0100, Julien Thierry wrote:
Add support for percpu_devid interrupts treated as NMIs.
Percpu_devid NMIs need to be setup/torn down on each CPU they target.
The same restrictions as for global NMIs still apply for percpu_devid NMIs.
Signed-off-by: Julien Thierry <julien.thierry@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
---
include/linux/interrupt.h | 9 +++
kernel/irq/manage.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 158 insertions(+)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 3b1a320..59d3877 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -168,10 +168,15 @@ struct irqaction {
devname, percpu_dev_id);
}
+extern int __must_check
+request_percpu_nmi(unsigned int irq, irq_handler_t handler,
+ const char *devname, void __percpu *dev);
+
extern const void *free_irq(unsigned int, void *);
extern void free_percpu_irq(unsigned int, void __percpu *);
extern const void *free_nmi(unsigned int irq, void *dev_id);
+extern void free_percpu_nmi(unsigned int irq, void __percpu *percpu_dev_id);
struct device;
@@ -224,7 +229,11 @@ struct irqaction {
extern void irq_wake_thread(unsigned int irq, void *dev_id);
extern void disable_nmi_nosync(unsigned int irq);
+extern void disable_percpu_nmi(unsigned int irq);
Shouldn't this be a disable_percpu_nmi_nosync() as disable_nmi_nosync()?
The naming of the disable_percpu_irq didn't include the nosync either
(and it doesn't wait for pending percpu_devid_irqs)
extern void enable_nmi(unsigned int irq);
+extern void enable_percpu_nmi(unsigned int irq, unsigned int type);
+extern int ready_percpu_nmi(unsigned int irq);
+extern void teardown_percpu_nmi(unsigned int irq);
/* The following three functions are for the core kernel use only. */
extern void suspend_device_irqs(void);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 3b87143..ad41c4d 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -2162,6 +2162,11 @@ void enable_percpu_irq(unsigned int irq, unsigned int type)
}
EXPORT_SYMBOL_GPL(enable_percpu_irq);
+void enable_percpu_nmi(unsigned int irq, unsigned int type)
+{
+ enable_percpu_irq(irq, type);
+}
+
/**
* irq_percpu_is_enabled - Check whether the per cpu irq is enabled
* @irq: Linux irq number to check for
@@ -2201,6 +2206,11 @@ void disable_percpu_irq(unsigned int irq)
}
EXPORT_SYMBOL_GPL(disable_percpu_irq);
+void disable_percpu_nmi(unsigned int irq)
+{
+ disable_percpu_irq(irq);
+}
+
/*
* Internal function to unregister a percpu irqaction.
*/
@@ -2232,6 +2242,8 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_
/* Found it - now remove it from the list of entries: */
desc->action = NULL;
+ desc->istate &= ~IRQS_NMI;
+
raw_spin_unlock_irqrestore(&desc->lock, flags);
unregister_handler_proc(irq, action);
@@ -2285,6 +2297,19 @@ void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
}
EXPORT_SYMBOL_GPL(free_percpu_irq);
+void free_percpu_nmi(unsigned int irq, void __percpu *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (!desc || !irq_settings_is_per_cpu_devid(desc))
+ return;
+
+ if (WARN_ON(!(desc->istate & IRQS_NMI)))
+ return;
+
+ kfree(__free_percpu_irq(irq, dev_id));
+}
+
/**
* setup_percpu_irq - setup a per-cpu interrupt
* @irq: Interrupt line to setup
@@ -2375,6 +2400,130 @@ int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
EXPORT_SYMBOL_GPL(__request_percpu_irq);
/**
+ * request_percpu_nmi - allocate a percpu interrupt line for NMI delivery
+ * @irq: Interrupt line to allocate
+ * @handler: Function to be called when the IRQ occurs.
+ * @devname: An ascii name for the claiming device
+ * @dev_id: A percpu cookie passed back to the handler function
+ *
+ * This call allocates interrupt resources and enables the
+ * interrupt on the local CPU. If the interrupt is supposed to be
+ * enabled on other CPUs, it has to be done on each CPU using
+ * enable_percpu_nmi().
+ *
+ * Dev_id must be globally unique. It is a per-cpu variable, and
+ * the handler gets called with the interrupted CPU's instance of
+ * that variable.
+ *
+ * Interrupt lines requested for NMI delivering should have auto enabling
+ * setting disabled.
+ *
+ * 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)
+{
+ struct irqaction *action;
+ struct irq_desc *desc;
+ unsigned long flags;
+ int retval;
+
+ if (!handler)
+ return -EINVAL;
+
+ desc = irq_to_desc(irq);
+
+ if (!desc || !irq_settings_can_request(desc)
+ || !irq_settings_is_per_cpu_devid(desc)
+ || irq_settings_can_autoenable(desc)
+ || !irq_supports_nmi(desc))
Shouldn't the logical operators go at the end of the line in a multi-line
statement?
Yes, I'll fix that.
+ return -EINVAL;
+
+ /* The line cannot already be NMI */
+ if (desc->istate & IRQS_NMI)
+ return -EINVAL;
+
+ action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+ if (!action)
+ return -ENOMEM;
+
+ action->handler = handler;
+ action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD
+ | IRQF_NOBALANCING;
Shouldn't IRQF_NOBALANCING be aligned with IRQF_PERCPU;
Yes, I'll fix this as well.
Thanks,
--
Julien Thierry