From fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204 Mon Sep 17 00:00:00 2001 From: Timothy Pearson Date: Wed, 23 Aug 2017 14:45:25 -0500 Subject: Initial import of modified Linux 2.6.28 tree Original upstream URL: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y --- kernel/irq/spurious.c | 300 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 300 insertions(+) create mode 100644 kernel/irq/spurious.c (limited to 'kernel/irq/spurious.c') diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c new file mode 100644 index 0000000..dd364c1 --- /dev/null +++ b/kernel/irq/spurious.c @@ -0,0 +1,300 @@ +/* + * linux/kernel/irq/spurious.c + * + * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar + * + * This file contains spurious interrupt handling. + */ + +#include +#include +#include +#include +#include +#include +#include + +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); -- cgit v1.1