linux/kernel/irq/spurious.c
Edward Donovan 52553ddffa genirq: fix regression in irqfixup, irqpoll
Commit fa27271bc8d2("genirq: Fixup poll handling") introduced a
regression that broke irqfixup/irqpoll for some hardware configurations.

Amidst reorganizing 'try_one_irq', that patch removed a test that
checked for 'action->handler' returning IRQ_HANDLED, before acting on
the interrupt.  Restoring this test back returns the functionality lost
since 2.6.39.  In the current set of tests, after 'action' is set, it
must precede '!action->next' to take effect.

With this and my previous patch to irq/spurious.c, c75d720fca, all
IRQ regressions that I have encountered are fixed.

Signed-off-by: Edward Donovan <edward.donovan@numble.net>
Reported-and-tested-by: Rogério Brito <rbrito@ime.usp.br>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org (2.6.39+)
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-11-28 08:43:09 -08:00

364 lines
8.6 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>
#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
}
/*
* 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 (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(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. Check for action->next as well.
*/
action = desc->action;
if (!action || !(action->flags & IRQF_SHARED) ||
(action->flags & __IRQF_TIMER) ||
(action->handler(irq, action->dev_id) == IRQ_HANDLED) ||
!action->next)
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;
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);
}
static inline int bad_action_ret(irqreturn_t action_ret)
{
if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
return 0;
return 1;
}
/*
* 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 (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);
action = desc->action;
while (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");
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;
/* we get here again via the threaded handler */
if (action_ret == IRQ_WAKE_THREAD)
return;
if (bad_action_ret(action_ret)) {
report_bad_irq(irq, desc, action_ret);
return;
}
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;
}
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);