linux/kernel/irq/spurious.c

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/*
* 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>
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);
/*
* Recovery handler for misrouted interrupts.
*/
static int try_one_irq(int irq, struct irq_desc *desc)
{
struct irqaction *action;
int ok = 0, work = 0;
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);
return ok;
}
/* 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(irq, 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(irq, 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(irq);
spin_unlock(&desc->lock);
return ok;
}
static int misrouted_irq(int irq)
{
struct irq_desc *desc;
int i, ok = 0;
for_each_irq_desc(i, desc) {
if (!i)
continue;
if (i == irq) /* Already tried */
continue;
if (try_one_irq(i, desc))
ok = 1;
}
/* So the caller can adjust the irq error counts */
return ok;
}
static void poll_all_shared_irqs(void)
{
struct irq_desc *desc;
int i;
for_each_irq_desc(i, desc) {
unsigned int status;
if (!i)
continue;
/* Racy but it doesn't matter */
status = desc->status;
barrier();
if (!(status & IRQ_SPURIOUS_DISABLED))
continue;
try_one_irq(i, desc);
}
}
static void poll_spurious_irqs(unsigned long dummy)
{
poll_all_shared_irqs();
mod_timer(&poll_spurious_irq_timer,
jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
}
#ifdef CONFIG_DEBUG_SHIRQ
void debug_poll_all_shared_irqs(void)
{
poll_all_shared_irqs();
}
#endif
/*
* 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,
IRQ: Maintain regs pointer globally rather than passing to IRQ handlers Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
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++;
[PATCH] genirq: rename desc->handler to desc->chip This patch-queue improves the generic IRQ layer to be truly generic, by adding various abstractions and features to it, without impacting existing functionality. While the queue can be best described as "fix and improve everything in the generic IRQ layer that we could think of", and thus it consists of many smaller features and lots of cleanups, the one feature that stands out most is the new 'irq chip' abstraction. The irq-chip abstraction is about describing and coding and IRQ controller driver by mapping its raw hardware capabilities [and quirks, if needed] in a straightforward way, without having to think about "IRQ flow" (level/edge/etc.) type of details. This stands in contrast with the current 'irq-type' model of genirq architectures, which 'mixes' raw hardware capabilities with 'flow' details. The patchset supports both types of irq controller designs at once, and converts i386 and x86_64 to the new irq-chip design. As a bonus side-effect of the irq-chip approach, chained interrupt controllers (master/slave PIC constructs, etc.) are now supported by design as well. The end result of this patchset intends to be simpler architecture-level code and more consolidation between architectures. We reused many bits of code and many concepts from Russell King's ARM IRQ layer, the merging of which was one of the motivations for this patchset. This patch: rename desc->handler to desc->chip. Originally i did not want to do this, because it's a big patch. But having both "desc->handler", "desc->handle_irq" and "action->handler" caused a large degree of confusion and made the code appear alot less clean than it truly is. I have also attempted a dual approach as well by introducing a desc->chip alias - but that just wasnt robust enough and broke frequently. So lets get over with this quickly. The conversion was done automatically via scripts and converts all the code in the kernel. This renaming patch is the first one amongst the patches, so that the remaining patches can stay flexible and can be merged and split up without having some big monolithic patch act as a merge barrier. [akpm@osdl.org: build fix] [akpm@osdl.org: another build fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-29 09:24:36 +00:00
desc->chip->disable(irq);
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);
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);