/* * 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_spurious_irqs(unsigned long dummy) { 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); } 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) * * 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); 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);