mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 02:09:42 +00:00
![Thomas Gleixner](/assets/img/avatar_default.png)
Uwe Kleine-Koenig has some strange hardware where one of the shared interrupts can be asserted during boot before the appropriate driver loads. Requesting the shared irq line from another driver result in a spurious interrupt storm which finally disables the interrupt line. I have seen similar behaviour on resume before (the hardware does not work anymore so I can not verify). Change the spurious disable logic to increment the disable depth and mark the interrupt with an extra flag which allows us to reenable the interrupt when a new driver arrives which requests the same irq line. In the worst case this will disable the irq again via the spurious trap, but there is a decent chance that the new driver is the one which can handle the already asserted interrupt and makes the box usable again. Eric Biederman said further: This case also happens on a regular basis in kdump kernels where we deliberately don't shutdown the hardware before starting the new kernel. This patch should reduce the need for using irqpoll in that situation by a small amount. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-and-Acked-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
256 lines
6.1 KiB
C
256 lines
6.1 KiB
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>
|
|
|
|
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 (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->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
|
|
desc->depth++;
|
|
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);
|