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   1 /*
   2  * linux/kernel/irq/spurious.c
   3  *
   4  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
   5  *
   6  * This file contains spurious interrupt handling.
   7  */
   8
   9 #include <linux/irq.h>
  10 #include <linux/module.h>
  11 #include <linux/kallsyms.h>
  12 #include <linux/interrupt.h>
  13
  14 static int irqfixup;
  15
  16 /*
  17  * Recovery handler for misrouted interrupts.
  18  */
  19
  20 static int misrouted_irq(int irq, struct pt_regs *regs)
  21 {
  22         int i;
  23         irq_desc_t *desc;
  24         int ok = 0;
  25         int work = 0;   /* Did we do work for a real IRQ */
  26
  27         for(i = 1; i < NR_IRQS; i++) {
  28                 struct irqaction *action;
  29
  30                 if (i == irq)   /* Already tried */
  31                         continue;
  32                 desc = &irq_desc[i];
  33                 spin_lock(&desc->lock);
  34                 action = desc->action;
  35                 /* Already running on another processor */
  36                 if (desc->status & IRQ_INPROGRESS) {
  37                         /*
  38                          * Already running: If it is shared get the other
  39                          * CPU to go looking for our mystery interrupt too
  40                          */
  41                         if (desc->action && (desc->action->flags & SA_SHIRQ))
  42                                 desc->status |= IRQ_PENDING;
  43                         spin_unlock(&desc->lock);
  44                         continue;
  45                 }
  46                 /* Honour the normal IRQ locking */
  47                 desc->status |= IRQ_INPROGRESS;
  48                 spin_unlock(&desc->lock);
  49                 while (action) {
  50                         /* Only shared IRQ handlers are safe to call */
  51                         if (action->flags & SA_SHIRQ) {
  52                                 if (action->handler(i, action->dev_id, regs) ==
  53                                                 IRQ_HANDLED)
  54                                         ok = 1;
  55                         }
  56                         action = action->next;
  57                 }
  58                 local_irq_disable();
  59                 /* Now clean up the flags */
  60                 spin_lock(&desc->lock);
  61                 action = desc->action;
  62
  63                 /*
  64                  * While we were looking for a fixup someone queued a real
  65                  * IRQ clashing with our walk
  66                  */
  67
  68                 while ((desc->status & IRQ_PENDING) && action) {
  69                         /*
  70                          * Perform real IRQ processing for the IRQ we deferred
  71                          */
  72                         work = 1;
  73                         spin_unlock(&desc->lock);
  74                         handle_IRQ_event(i, regs, action);
  75                         spin_lock(&desc->lock);
  76                         desc->status &= ~IRQ_PENDING;
  77                 }
  78                 desc->status &= ~IRQ_INPROGRESS;
  79                 /*
  80                  * If we did actual work for the real IRQ line we must let the
  81                  * IRQ controller clean up too
  82                  */
  83                 if(work)
  84                         desc->handler->end(i);
  85                 spin_unlock(&desc->lock);
  86         }
  87         /* So the caller can adjust the irq error counts */
  88         return ok;
  89 }
  90
  91 /*
  92  * If 99,900 of the previous 100,000 interrupts have not been handled
  93  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
  94  * and try to turn the IRQ off.
  95  *
  96  * (The other 100-of-100,000 interrupts may have been a correctly
  97  *  functioning device sharing an IRQ with the failing one)
  98  *
  99  * Called under desc->lock
 100  */
 101
 102 static void
 103 __report_bad_irq(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret)
 104 {
 105         struct irqaction *action;
 106
 107         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 108                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 109                                 irq, action_ret);
 110         } else {
 111                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 112                                 "the \"irqpoll\" option)\n", irq);
 113         }
 114         dump_stack();
 115         printk(KERN_ERR "handlers:\n");
 116         action = desc->action;
 117         while (action) {
 118                 printk(KERN_ERR "[<%p>]", action->handler);
 119                 print_symbol(" (%s)",
 120                         (unsigned long)action->handler);
 121                 printk("\n");
 122                 action = action->next;
 123         }
 124 }
 125
 126 static void report_bad_irq(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret)
 127 {
 128         static int count = 100;
 129
 130         if (count > 0) {
 131                 count--;
 132                 __report_bad_irq(irq, desc, action_ret);
 133         }
 134 }
 135
 136 void note_interrupt(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret,
 137                         struct pt_regs *regs)
 138 {
 139         if (action_ret != IRQ_HANDLED) {
 140                 desc->irqs_unhandled++;
 141                 if (action_ret != IRQ_NONE)
 142                         report_bad_irq(irq, desc, action_ret);
 143         }
 144
 145         if (unlikely(irqfixup)) {
 146                 /* Don't punish working computers */
 147                 if ((irqfixup == 2 && irq == 0) || action_ret == IRQ_NONE) {
 148                         int ok = misrouted_irq(irq, regs);
 149                         if (action_ret == IRQ_NONE)
 150                                 desc->irqs_unhandled -= ok;
 151                 }
 152         }
 153
 154         desc->irq_count++;
 155         if (desc->irq_count < 100000)
 156                 return;
 157
 158         desc->irq_count = 0;
 159         if (desc->irqs_unhandled > 99900) {
 160                 /*
 161                  * The interrupt is stuck
 162                  */
 163                 __report_bad_irq(irq, desc, action_ret);
 164                 /*
 165                  * Now kill the IRQ
 166                  */
 167                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 168                 desc->status |= IRQ_DISABLED;
 169                 desc->handler->disable(irq);
 170         }
 171         desc->irqs_unhandled = 0;
 172 }
 173
 174 int noirqdebug;
 175
 176 int __init noirqdebug_setup(char *str)
 177 {
 178         noirqdebug = 1;
 179         printk(KERN_INFO "IRQ lockup detection disabled\n");
 180         return 1;
 181 }
 182
 183 __setup("noirqdebug", noirqdebug_setup);
 184
 185 static int __init irqfixup_setup(char *str)
 186 {
 187         irqfixup = 1;
 188         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 189         printk(KERN_WARNING "This may impact system performance.\n");
 190         return 1;
 191 }
 192
 193 __setup("irqfixup", irqfixup_setup);
 194
 195 static int __init irqpoll_setup(char *str)
 196 {
 197         irqfixup = 2;
 198         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 199                                 "enabled\n");
 200         printk(KERN_WARNING "This may significantly impact system "
 201                                 "performance\n");
 202         return 1;
 203 }
 204
 205 __setup("irqpoll", irqpoll_setup);