kernel/irq/spurious.c - maze/linux - Git at Google

 /*
  * 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 (desc->istate & IRQS_INPROGRESS)
 			cpu_relax();
 		raw_spin_lock(&desc->lock);
 	} while (desc->istate & IRQS_INPROGRESS);
 	/* Might have been disabled in meantime */
 	return !(desc->istate & IRQS_DISABLED) && desc->action;
 #else
 	return false;
 #endif
 }


 /*
  * Recovery handler for misrouted interrupts.
  */
 static int try_one_irq(int irq, struct irq_desc *desc, bool force)
 {
 	irqreturn_t ret = IRQ_NONE;
 	struct irqaction *action;

 	raw_spin_lock(&desc->lock);

 	/* PER_CPU and nested thread interrupts are never polled */
 	if (desc->status & (IRQ_PER_CPU | IRQ_NESTED_THREAD))
 		goto out;

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

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

 	/* Already running on another processor */
 	if (desc->istate & IRQS_INPROGRESS) {
 		/*
 		 * Already running: If it is shared get the other
 		 * CPU to go looking for our mystery interrupt too
 		 */
 		irq_compat_set_pending(desc);
 		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;
 		action = desc->action;
 	} while ((desc->istate & IRQS_PENDING) && action);
 	desc->istate &= ~IRQS_POLL_INPROGRESS;
 out:
 	raw_spin_unlock(&desc->lock);
 	return ret == IRQ_HANDLED;
 }

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

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

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

 	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 		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);
 	action = desc->action;
 	while (action) {
 		printk(KERN_ERR "[<%p>]", action->handler);
 		print_symbol(" (%s)",
 			(unsigned long)action->handler);
 		printk("\n");
 		action = action->next;
 	}
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 }

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

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

 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);
 }

 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 		    irqreturn_t action_ret)
 {
 	if (desc->istate & IRQS_POLL_INPROGRESS)
 		return;

 	if (unlikely(action_ret != IRQ_HANDLED)) {
 		/*
 		 * 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;
 		if (unlikely(action_ret != IRQ_NONE))
 			report_bad_irq(irq, desc, action_ret);
 	}

 	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(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;
 }

 int noirqdebug __read_mostly;

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

 	return 1;
 }

 __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;
 }

 __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;
 }

 __setup("irqpoll", irqpoll_setup);
	/*
	* 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 (desc->istate & IRQS_INPROGRESS)
	cpu_relax();
	raw_spin_lock(&desc->lock);
	} while (desc->istate & IRQS_INPROGRESS);
	/* Might have been disabled in meantime */
	return !(desc->istate & IRQS_DISABLED) && desc->action;
	#else
	return false;
	#endif
	}


	/*
	* Recovery handler for misrouted interrupts.
	*/
	static int try_one_irq(int irq, struct irq_desc *desc, bool force)
	{
	irqreturn_t ret = IRQ_NONE;
	struct irqaction *action;

	raw_spin_lock(&desc->lock);

	/* PER_CPU and nested thread interrupts are never polled */
	if (desc->status & (IRQ_PER_CPU \| IRQ_NESTED_THREAD))
	goto out;

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

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

	/* Already running on another processor */
	if (desc->istate & IRQS_INPROGRESS) {
	/*
	* Already running: If it is shared get the other
	* CPU to go looking for our mystery interrupt too
	*/
	irq_compat_set_pending(desc);
	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;
	action = desc->action;
	} while ((desc->istate & IRQS_PENDING) && action);
	desc->istate &= ~IRQS_POLL_INPROGRESS;
	out:
	raw_spin_unlock(&desc->lock);
	return ret == IRQ_HANDLED;
	}

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

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

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

	if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
	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);
	action = desc->action;
	while (action) {
	printk(KERN_ERR "[<%p>]", action->handler);
	print_symbol(" (%s)",
	(unsigned long)action->handler);
	printk("\n");
	action = action->next;
	}
	raw_spin_unlock_irqrestore(&desc->lock, flags);
	}

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

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

	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);
	}

	void note_interrupt(unsigned int irq, struct irq_desc *desc,
	irqreturn_t action_ret)
	{
	if (desc->istate & IRQS_POLL_INPROGRESS)
	return;

	if (unlikely(action_ret != IRQ_HANDLED)) {
	/*
	* 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;
	if (unlikely(action_ret != IRQ_NONE))
	report_bad_irq(irq, desc, action_ret);
	}

	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(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;
	}

	int noirqdebug __read_mostly;

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

	return 1;
	}

	__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;
	}

	__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;
	}

	__setup("irqpoll", irqpoll_setup);