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Commit 4b078c3f authored by Julien Thierry's avatar Julien Thierry Committed by Marc Zyngier
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genirq: Provide NMI management for percpu_devid interrupts 



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: default avatarJulien Thierry <julien.thierry@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent b525903c

include/linux/interrupt.h

+9 −0
Original line number Diff line number Diff line
@@ -168,10 +168,15 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler, 
				    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 @@ extern bool irq_percpu_is_enabled(unsigned int irq); 
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);

extern void enable_nmi(unsigned int irq);

extern void enable_percpu_nmi(unsigned int irq, unsigned int type);

extern int prepare_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);

kernel/irq/manage.c

+177 −0
Original line number Diff line number Diff line
@@ -2182,6 +2182,11 @@ 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
@@ -2221,6 +2226,11 @@ 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.

 */
@@ -2252,6 +2262,8 @@ 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);
@@ -2305,6 +2317,19 @@ 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
@@ -2394,6 +2419,158 @@ 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.

 *	@name: An ascii name for the claiming device

 *	@dev_id: A percpu cookie passed back to the handler function

 *

 *	This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs

 *	have to be setup on each CPU by calling ready_percpu_nmi() before being

 *	enabled on the same CPU by 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))

		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;

	action->name = name;

	action->percpu_dev_id = dev_id;



	retval = irq_chip_pm_get(&desc->irq_data);

	if (retval < 0)

		goto err_out;



	retval = __setup_irq(irq, desc, action);

	if (retval)

		goto err_irq_setup;



	raw_spin_lock_irqsave(&desc->lock, flags);

	desc->istate |= IRQS_NMI;

	raw_spin_unlock_irqrestore(&desc->lock, flags);



	return 0;



err_irq_setup:

	irq_chip_pm_put(&desc->irq_data);

err_out:

	kfree(action);



	return retval;

}



/**

 *	prepare_percpu_nmi - performs CPU local setup for NMI delivery

 *	@irq: Interrupt line to prepare for NMI delivery

 *

 *	This call prepares an interrupt line to deliver NMI on the current CPU,

 *	before that interrupt line gets enabled with enable_percpu_nmi().

 *

 *	As a CPU local operation, this should be called from non-preemptible

 *	context.

 *

 *	If the interrupt line cannot be used to deliver NMIs, function

 *	will fail returning a negative value.

 */

int prepare_percpu_nmi(unsigned int irq)

{

	unsigned long flags;

	struct irq_desc *desc;

	int ret = 0;



	WARN_ON(preemptible());



	desc = irq_get_desc_lock(irq, &flags,

				 IRQ_GET_DESC_CHECK_PERCPU);

	if (!desc)

		return -EINVAL;



	if (WARN(!(desc->istate & IRQS_NMI),

		 KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n",

		 irq)) {

		ret = -EINVAL;

		goto out;

	}



	ret = irq_nmi_setup(desc);

	if (ret) {

		pr_err("Failed to setup NMI delivery: irq %u\n", irq);

		goto out;

	}



out:

	irq_put_desc_unlock(desc, flags);

	return ret;

}



/**

 *	teardown_percpu_nmi - undoes NMI setup of IRQ line

 *	@irq: Interrupt line from which CPU local NMI configuration should be

 *	      removed

 *

 *	This call undoes the setup done by prepare_percpu_nmi().

 *

 *	IRQ line should not be enabled for the current CPU.

 *

 *	As a CPU local operation, this should be called from non-preemptible

 *	context.

 */

void teardown_percpu_nmi(unsigned int irq)

{

	unsigned long flags;

	struct irq_desc *desc;



	WARN_ON(preemptible());



	desc = irq_get_desc_lock(irq, &flags,

				 IRQ_GET_DESC_CHECK_PERCPU);

	if (!desc)

		return;



	if (WARN_ON(!(desc->istate & IRQS_NMI)))

		goto out;



	irq_nmi_teardown(desc);

out:

	irq_put_desc_unlock(desc, flags);

}



/**

 *	irq_get_irqchip_state - returns the irqchip state of a interrupt.

 *	@irq: Interrupt line that is forwarded to a VM