Commit 1f85b1f5 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

genirq: Add return value to check_irq_resend() 



In preparation for an interrupt injection interface which can be used
safely by error injection mechanisms. e.g. PCI-E/ AER, add a return value
to check_irq_resend() so errors can be propagated to the caller.

Split out the software resend code so the ugly #ifdef in check_irq_resend()
goes away and the whole thing becomes readable.

Fix up the caller in debugfs. The caller in irq_startup() does not care
about the return value as this is unconditionally invoked for all
interrupts and the resend is best effort anyway.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lkml.kernel.org/r/20200306130623.775200917@linutronix.de
parent 008f1d60

kernel/irq/debugfs.c

+1 −2
Original line number Diff line number Diff line
@@ -218,8 +218,7 @@ static ssize_t irq_debug_write(struct file *file, const char __user *user_buf, 
			err = -EINVAL;

		} else {

			desc->istate |= IRQS_PENDING;

			check_irq_resend(desc);

			err = 0;

			err = check_irq_resend(desc);

		}



		raw_spin_unlock_irqrestore(&desc->lock, flags);

kernel/irq/internals.h

+1 −1
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc); 
irqreturn_t handle_irq_event(struct irq_desc *desc);



/* Resending of interrupts :*/

void check_irq_resend(struct irq_desc *desc);

int check_irq_resend(struct irq_desc *desc);

bool irq_wait_for_poll(struct irq_desc *desc);

void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action);

kernel/irq/resend.c

+49 −34
Original line number Diff line number Diff line
@@ -47,57 +47,72 @@ static void resend_irqs(unsigned long arg) 
/* Tasklet to handle resend: */

static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);



#endif



/*

 * IRQ resend

 *

 * Is called with interrupts disabled and desc->lock held.

 */

void check_irq_resend(struct irq_desc *desc)

static int irq_sw_resend(struct irq_desc *desc)

{

	unsigned int irq = irq_desc_get_irq(desc);



	/*

	 * We do not resend level type interrupts. Level type

	 * interrupts are resent by hardware when they are still

	 * active. Clear the pending bit so suspend/resume does not

	 * get confused.

	 * Validate whether this interrupt can be safely injected from

	 * non interrupt context

	 */

	if (irq_settings_is_level(desc)) {

		desc->istate &= ~IRQS_PENDING;

		return;

	}

	if (desc->istate & IRQS_REPLAY)

		return;

	if (desc->istate & IRQS_PENDING) {

		desc->istate &= ~IRQS_PENDING;

		desc->istate |= IRQS_REPLAY;



		if ((!desc->irq_data.chip->irq_retrigger ||

		    !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) &&

		    !handle_enforce_irqctx(&desc->irq_data)) {

#ifdef CONFIG_HARDIRQS_SW_RESEND

			unsigned int irq = irq_desc_get_irq(desc);

	if (handle_enforce_irqctx(&desc->irq_data))

		return -EINVAL;



	/*

			 * If the interrupt is running in the thread

			 * context of the parent irq we need to be

			 * careful, because we cannot trigger it

	 * If the interrupt is running in the thread context of the parent

	 * irq we need to be careful, because we cannot trigger it

	 * directly.

	 */

	if (irq_settings_is_nested_thread(desc)) {

		/*

				 * If the parent_irq is valid, we

				 * retrigger the parent, otherwise we

				 * do nothing.

		 * If the parent_irq is valid, we retrigger the parent,

		 * otherwise we do nothing.

		 */

		if (!desc->parent_irq)

					return;

			return -EINVAL;

		irq = desc->parent_irq;

	}



	/* Set it pending and activate the softirq: */

	set_bit(irq, irqs_resend);

	tasklet_schedule(&resend_tasklet);

	return 0;

}



#else

static int irq_sw_resend(struct irq_desc *desc)

{

	return -EINVAL;

}

#endif



/*

 * IRQ resend

 *

 * Is called with interrupts disabled and desc->lock held.

 */

int check_irq_resend(struct irq_desc *desc)

{

	/*

	 * We do not resend level type interrupts. Level type interrupts

	 * are resent by hardware when they are still active. Clear the

	 * pending bit so suspend/resume does not get confused.

	 */

	if (irq_settings_is_level(desc)) {

		desc->istate &= ~IRQS_PENDING;

		return -EINVAL;

	}



	if (desc->istate & IRQS_REPLAY)

		return -EBUSY;



	if (desc->istate & IRQS_PENDING) {

		desc->istate &= ~IRQS_PENDING;

		desc->istate |= IRQS_REPLAY;



		if (!desc->irq_data.chip->irq_retrigger ||

		    !desc->irq_data.chip->irq_retrigger(&desc->irq_data))

		    return irq_sw_resend(desc);

	}

	return 0;

}

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