/*
* linux/kernel/irq/spurious.c
*
* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
*
* This file contains spurious interrupt handling.
*/
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <linux/interrupt.h>
#include <linux/moduleparam.h>
static int irqfixup __read_mostly;
/*
* Recovery handler for misrouted interrupts.
*/
static int misrouted_irq(int irq)
{
int i;
int ok = 0;
int work = 0; /* Did we do work for a real IRQ */
for (i = 1; i < NR_IRQS; i++) {
struct irq_desc *desc = irq_desc + i;
struct irqaction *action;
if (i == irq) /* Already tried */
continue;
spin_lock(&desc->lock);
/* Already running on another processor */
if (desc->status & IRQ_INPROGRESS) {
/*
* Already running: If it is shared get the other
* CPU to go looking for our mystery interrupt too
*/
if (desc->action && (desc->action->flags & IRQF_SHARED))
desc->status |= IRQ_PENDING;
spin_unlock(&desc->lock);
continue;
}
/* Honour the normal IRQ locking */
desc->status |= IRQ_INPROGRESS;
action = desc->action;
spin_unlock(&desc->lock);
while (action) {
/* Only shared IRQ handlers are safe to call */
if (action->flags & IRQF_SHARED) {
if (action->handler(i, action->dev_id) ==
IRQ_HANDLED)
ok = 1;
}
action = action->next;
}
local_irq_disable();
/* Now clean up the flags */
spin_lock(&desc->lock);
action = desc->action;
/*
* While we were looking for a fixup someone queued a real
* IRQ clashing with our walk:
*/
while ((desc->status & IRQ_PENDING) && action) {
/*
* Perform real IRQ processing for the IRQ we deferred
*/
work = 1;
spin_unlock(&desc->lock);
handle_IRQ_event(i, action);
spin_lock(&desc->lock);
desc->status &= ~IRQ_PENDING;
}
desc->status &= ~IRQ_INPROGRESS;
/*
* If we did actual work for the real IRQ line we must let the
* IRQ controller clean up too
*/
if (work && desc->chip && desc->chip->end)
desc->chip->end(i);
spin_unlock(&desc->lock);
}
/* So the caller can adjust the irq error counts */
return ok;
}
/*
* 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)
*
* Called under desc->lock
*/
static void
__report_bad_irq(unsigned int irq, struct irq_desc *desc,
irqreturn_t action_ret)
{
struct irqaction *action;
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");
action = desc->action;
while (action) {
printk(KERN_ERR "[<%p>]", action->handler);
print_symbol(" (%s)",
(unsigned long)action->handler);
printk("\n");
action = action->next;
}
}
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 (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 couter becomes a doomsday timer for otherwise
* working systems
*/
if (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->status |= IRQ_DISABLED;
desc->depth = 1;
desc->chip->disable(irq);
}
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);
MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");
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);
