Release 4.7 kernel/irq/spurious.c

/*
 * linux/kernel/irq/spurious.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains spurious interrupt handling.
 */

#include <linux/jiffies.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
#include <linux/timer.h>

#include "internals.h"


static int irqfixup __read_mostly;


#define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
static void poll_spurious_irqs(unsigned long dummy);
static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);

static int irq_poll_cpu;

static atomic_t irq_poll_active;

/*
 * We wait here for a poller to finish.
 *
 * If the poll runs on this CPU, then we yell loudly and return
 * false. That will leave the interrupt line disabled in the worst
 * case, but it should never happen.
 *
 * We wait until the poller is done and then recheck disabled and
 * action (about to be disabled). Only if it's still active, we return
 * true and let the handler run.
 */


bool irq_wait_for_poll(struct irq_desc *desc)
{
	if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
		      "irq poll in progress on cpu %d for irq %d\n",
		      smp_processor_id(), desc->irq_data.irq))
		return false;

#ifdef CONFIG_SMP
	do {
		raw_spin_unlock(&desc->lock);
		while (irqd_irq_inprogress(&desc->irq_data))
			cpu_relax();
		raw_spin_lock(&desc->lock);
	} while (irqd_irq_inprogress(&desc->irq_data));
	/* Might have been disabled in meantime */
	return !irqd_irq_disabled(&desc->irq_data) && desc->action;
#else
	return false;
#endif
}


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/*
 * Recovery handler for misrouted interrupts.
 */


static int try_one_irq(struct irq_desc *desc, bool force)
{
	irqreturn_t ret = IRQ_NONE;
	struct irqaction *action;

	raw_spin_lock(&desc->lock);

	/*
         * PER_CPU, nested thread interrupts and interrupts explicitely
         * marked polled are excluded from polling.
         */
	if (irq_settings_is_per_cpu(desc) ||
	    irq_settings_is_nested_thread(desc) ||
	    irq_settings_is_polled(desc))
		goto out;

	/*
         * Do not poll disabled interrupts unless the spurious
         * disabled poller asks explicitely.
         */
	if (irqd_irq_disabled(&desc->irq_data) && !force)
		goto out;

	/*
         * All handlers must agree on IRQF_SHARED, so we test just the
         * first.
         */
	action = desc->action;
	if (!action || !(action->flags & IRQF_SHARED) ||
	    (action->flags & __IRQF_TIMER))
		goto out;

	/* Already running on another processor */
	if (irqd_irq_inprogress(&desc->irq_data)) {
		/*
                 * Already running: If it is shared get the other
                 * CPU to go looking for our mystery interrupt too
                 */
		desc->istate |= IRQS_PENDING;
		goto out;
	}

	/* Mark it poll in progress */
	desc->istate |= IRQS_POLL_INPROGRESS;
	do {
		if (handle_irq_event(desc) == IRQ_HANDLED)
			ret = IRQ_HANDLED;
		/* Make sure that there is still a valid action */
		action = desc->action;
	} while ((desc->istate & IRQS_PENDING) && action);
	desc->istate &= ~IRQS_POLL_INPROGRESS;
out:
	raw_spin_unlock(&desc->lock);
	return ret == IRQ_HANDLED;
}

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static int misrouted_irq(int irq)
{
	struct irq_desc *desc;
	int i, ok = 0;

	if (atomic_inc_return(&irq_poll_active) != 1)
		goto out;

	irq_poll_cpu = smp_processor_id();

	for_each_irq_desc(i, desc) {
		if (!i)
			 continue;

		if (i == irq)	/* Already tried */
			continue;

		if (try_one_irq(desc, false))
			ok = 1;
	}
out:
	atomic_dec(&irq_poll_active);
	/* So the caller can adjust the irq error counts */
	return ok;
}

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static void poll_spurious_irqs(unsigned long dummy)
{
	struct irq_desc *desc;
	int i;

	if (atomic_inc_return(&irq_poll_active) != 1)
		goto out;
	irq_poll_cpu = smp_processor_id();

	for_each_irq_desc(i, desc) {
		unsigned int state;

		if (!i)
			 continue;

		/* Racy but it doesn't matter */
		state = desc->istate;
		barrier();
		if (!(state & IRQS_SPURIOUS_DISABLED))
			continue;

		local_irq_disable();
		try_one_irq(desc, true);
		local_irq_enable();
	}
out:
	atomic_dec(&irq_poll_active);
	mod_timer(&poll_spurious_irq_timer,
		  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}

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static inline int bad_action_ret(irqreturn_t action_ret)
{
	if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
		return 0;
	return 1;
}

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/*
 * If 99,900 of the previous 100,000 interrupts have not been handled
 * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 * and try to turn the IRQ off.
 *
 * (The other 100-of-100,000 interrupts may have been a correctly
 *  functioning device sharing an IRQ with the failing one)
 */


static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
{
	unsigned int irq = irq_desc_get_irq(desc);
	struct irqaction *action;
	unsigned long flags;

	if (bad_action_ret(action_ret)) {
		printk(KERN_ERR "irq event %d: bogus return value %x\n",
				irq, action_ret);
	} else {
		printk(KERN_ERR "irq %d: nobody cared (try booting with "
				"the \"irqpoll\" option)\n", irq);
	}
	dump_stack();
	printk(KERN_ERR "handlers:\n");

	/*
         * We need to take desc->lock here. note_interrupt() is called
         * w/o desc->lock held, but IRQ_PROGRESS set. We might race
         * with something else removing an action. It's ok to take
         * desc->lock here. See synchronize_irq().
         */
	raw_spin_lock_irqsave(&desc->lock, flags);
	for_each_action_of_desc(desc, action) {
		printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
		if (action->thread_fn)
			printk(KERN_CONT " threaded [<%p>] %pf",
					action->thread_fn, action->thread_fn);
		printk(KERN_CONT "\n");
	}
	raw_spin_unlock_irqrestore(&desc->lock, flags);
}

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static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
{
	static int count = 100;

	if (count > 0) {
		count--;
		__report_bad_irq(desc, action_ret);
	}
}

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static inline int

try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
		  irqreturn_t action_ret)
{
	struct irqaction *action;

	if (!irqfixup)
		return 0;

	/* We didn't actually handle the IRQ - see if it was misrouted? */
	if (action_ret == IRQ_NONE)
		return 1;

	/*
         * But for 'irqfixup == 2' we also do it for handled interrupts if
         * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
         * traditional PC timer interrupt.. Legacy)
         */
	if (irqfixup < 2)
		return 0;

	if (!irq)
		return 1;

	/*
         * Since we don't get the descriptor lock, "action" can
         * change under us.  We don't really care, but we don't
         * want to follow a NULL pointer. So tell the compiler to
         * just load it once by using a barrier.
         */
	action = desc->action;
	barrier();
	return action && (action->flags & IRQF_IRQPOLL);
}

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#define SPURIOUS_DEFERRED	0x80000000



void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret)
{
	unsigned int irq;

	if (desc->istate & IRQS_POLL_INPROGRESS ||
	    irq_settings_is_polled(desc))
		return;

	if (bad_action_ret(action_ret)) {
		report_bad_irq(desc, action_ret);
		return;
	}

	/*
         * We cannot call note_interrupt from the threaded handler
         * because we need to look at the compound of all handlers
         * (primary and threaded). Aside of that in the threaded
         * shared case we have no serialization against an incoming
         * hardware interrupt while we are dealing with a threaded
         * result.
         *
         * So in case a thread is woken, we just note the fact and
         * defer the analysis to the next hardware interrupt.
         *
         * The threaded handlers store whether they sucessfully
         * handled an interrupt and we check whether that number
         * changed versus the last invocation.
         *
         * We could handle all interrupts with the delayed by one
         * mechanism, but for the non forced threaded case we'd just
         * add pointless overhead to the straight hardirq interrupts
         * for the sake of a few lines less code.
         */
	if (action_ret & IRQ_WAKE_THREAD) {
		/*
                 * There is a thread woken. Check whether one of the
                 * shared primary handlers returned IRQ_HANDLED. If
                 * not we defer the spurious detection to the next
                 * interrupt.
                 */
		if (action_ret == IRQ_WAKE_THREAD) {
			int handled;
			/*
                         * We use bit 31 of thread_handled_last to
                         * denote the deferred spurious detection
                         * active. No locking necessary as
                         * thread_handled_last is only accessed here
                         * and we have the guarantee that hard
                         * interrupts are not reentrant.
                         */
			if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) {
				desc->threads_handled_last |= SPURIOUS_DEFERRED;
				return;
			}
			/*
                         * Check whether one of the threaded handlers
                         * returned IRQ_HANDLED since the last
                         * interrupt happened.
                         *
                         * For simplicity we just set bit 31, as it is
                         * set in threads_handled_last as well. So we
                         * avoid extra masking. And we really do not
                         * care about the high bits of the handled
                         * count. We just care about the count being
                         * different than the one we saw before.
                         */
			handled = atomic_read(&desc->threads_handled);
			handled |= SPURIOUS_DEFERRED;
			if (handled != desc->threads_handled_last) {
				action_ret = IRQ_HANDLED;
				/*
                                 * Note: We keep the SPURIOUS_DEFERRED
                                 * bit set. We are handling the
                                 * previous invocation right now.
                                 * Keep it for the current one, so the
                                 * next hardware interrupt will
                                 * account for it.
                                 */
				desc->threads_handled_last = handled;
			} else {
				/*
                                 * None of the threaded handlers felt
                                 * responsible for the last interrupt
                                 *
                                 * We keep the SPURIOUS_DEFERRED bit
                                 * set in threads_handled_last as we
                                 * need to account for the current
                                 * interrupt as well.
                                 */
				action_ret = IRQ_NONE;
			}
		} else {
			/*
                         * One of the primary handlers returned
                         * IRQ_HANDLED. So we don't care about the
                         * threaded handlers on the same line. Clear
                         * the deferred detection bit.
                         *
                         * In theory we could/should check whether the
                         * deferred bit is set and take the result of
                         * the previous run into account here as
                         * well. But it's really not worth the
                         * trouble. If every other interrupt is
                         * handled we never trigger the spurious
                         * detector. And if this is just the one out
                         * of 100k unhandled ones which is handled
                         * then we merily delay the spurious detection
                         * by one hard interrupt. Not a real problem.
                         */
			desc->threads_handled_last &= ~SPURIOUS_DEFERRED;
		}
	}

	if (unlikely(action_ret == IRQ_NONE)) {
		/*
                 * If we are seeing only the odd spurious IRQ caused by
                 * bus asynchronicity then don't eventually trigger an error,
                 * otherwise the counter becomes a doomsday timer for otherwise
                 * working systems
                 */
		if (time_after(jiffies, desc->last_unhandled + HZ/10))
			desc->irqs_unhandled = 1;
		else
			desc->irqs_unhandled++;
		desc->last_unhandled = jiffies;
	}

	irq = irq_desc_get_irq(desc);
	if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
		int ok = misrouted_irq(irq);
		if (action_ret == IRQ_NONE)
			desc->irqs_unhandled -= ok;
	}

	desc->irq_count++;
	if (likely(desc->irq_count < 100000))
		return;

	desc->irq_count = 0;
	if (unlikely(desc->irqs_unhandled > 99900)) {
		/*
                 * The interrupt is stuck
                 */
		__report_bad_irq(desc, action_ret);
		/*
                 * Now kill the IRQ
                 */
		printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
		desc->istate |= IRQS_SPURIOUS_DISABLED;
		desc->depth++;
		irq_disable(desc);

		mod_timer(&poll_spurious_irq_timer,
			  jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
	}
	desc->irqs_unhandled = 0;
}

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jiang liu
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eric w. biederman
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1
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andreas mohr
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2.83%
1
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linus torvalds
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bool noirqdebug __read_mostly;



int noirqdebug_setup(char *str)
{
	noirqdebug = 1;
	printk(KERN_INFO "IRQ lockup detection disabled\n");

	return 1;
}

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__setup("noirqdebug", noirqdebug_setup);
module_param(noirqdebug, bool, 0644);
MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");



static int __init irqfixup_setup(char *str)
{
	irqfixup = 1;
	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
	printk(KERN_WARNING "This may impact system performance.\n");

	return 1;
}

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__setup("irqfixup", irqfixup_setup);
module_param(irqfixup, int, 0644);



static int __init irqpoll_setup(char *str)
{
	irqfixup = 2;
	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
				"enabled\n");
	printk(KERN_WARNING "This may significantly impact system "
				"performance\n");
	return 1;
}

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__setup("irqpoll", irqpoll_setup);
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9.89%
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2.22%
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linus torvalds
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6.72%
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2.22%
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sebastian andrzej siewior
71
5.49%
2
4.44%
andi kleen
andi kleen
28
2.16%
1
2.22%
yinghai lu
yinghai lu
27
2.09%
2
4.44%
jiang liu
jiang liu
20
1.55%
2
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andreas mohr
11
0.85%
1
2.22%
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caglar onur
8
0.62%
1
2.22%
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daniel lezcano
6
0.46%
1
2.22%
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yong zhang
6
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1
2.22%
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bernhard walle
1
0.08%
1
2.22%
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1
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0.08%
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0.08%
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edward donovan
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1
2.22%
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Directory: kernel/irq

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