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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 __read_mostly;
  15
  16 /*
  17  * Recovery handler for misrouted interrupts.
  18  */
  19 static int misrouted_irq(int irq)
  20 {
  21         int i;
  22         int ok = 0;
  23         int work = 0;   /* Did we do work for a real IRQ */
  24
  25         for (i = 1; i < NR_IRQS; i++) {
  26                 struct irq_desc *desc = irq_desc + i;
  27                 struct irqaction *action;
  28
  29                 if (i == irq)   /* Already tried */
  30                         continue;
  31
  32                 spin_lock(&desc->lock);
  33                 /* Already running on another processor */
  34                 if (desc->status & IRQ_INPROGRESS) {
  35                         /*
  36                          * Already running: If it is shared get the other
  37                          * CPU to go looking for our mystery interrupt too
  38                          */
  39                         if (desc->action && (desc->action->flags & IRQF_SHARED))
  40                                 desc->status |= IRQ_PENDING;
  41                         spin_unlock(&desc->lock);
  42                         continue;
  43                 }
  44                 /* Honour the normal IRQ locking */
  45                 desc->status |= IRQ_INPROGRESS;
  46                 action = desc->action;
  47                 spin_unlock(&desc->lock);
  48
  49                 while (action) {
  50                         /* Only shared IRQ handlers are safe to call */
  51                         if (action->flags & IRQF_SHARED) {
  52                                 if (action->handler(i, action->dev_id) ==
  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                 while ((desc->status & IRQ_PENDING) && action) {
  68                         /*
  69                          * Perform real IRQ processing for the IRQ we deferred
  70                          */
  71                         work = 1;
  72                         spin_unlock(&desc->lock);
  73                         handle_IRQ_event(i, action);
  74                         spin_lock(&desc->lock);
  75                         desc->status &= ~IRQ_PENDING;
  76                 }
  77                 desc->status &= ~IRQ_INPROGRESS;
  78                 /*
  79                  * If we did actual work for the real IRQ line we must let the
  80                  * IRQ controller clean up too
  81                  */
  82                 if (work && desc->chip && desc->chip->end)
  83                         desc->chip->end(i);
  84                 spin_unlock(&desc->lock);
  85         }
  86         /* So the caller can adjust the irq error counts */
  87         return ok;
  88 }
  89
  90 /*
  91  * If 99,900 of the previous 100,000 interrupts have not been handled
  92  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
  93  * and try to turn the IRQ off.
  94  *
  95  * (The other 100-of-100,000 interrupts may have been a correctly
  96  *  functioning device sharing an IRQ with the failing one)
  97  *
  98  * Called under desc->lock
  99  */
 100
 101 static void
 102 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 103                  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
 117         action = desc->action;
 118         while (action) {
 119                 printk(KERN_ERR "[<%p>]", action->handler);
 120                 print_symbol(" (%s)",
 121                         (unsigned long)action->handler);
 122                 printk("\n");
 123                 action = action->next;
 124         }
 125 }
 126
 127 static void
 128 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 129 {
 130         static int count = 100;
 131
 132         if (count > 0) {
 133                 count--;
 134                 __report_bad_irq(irq, desc, action_ret);
 135         }
 136 }
 137
 138 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 139                     irqreturn_t action_ret)
 140 {
 141         if (unlikely(action_ret != IRQ_HANDLED)) {
 142                 desc->irqs_unhandled++;
 143                 if (unlikely(action_ret != IRQ_NONE))
 144                         report_bad_irq(irq, desc, action_ret);
 145         }
 146
 147         if (unlikely(irqfixup)) {
 148                 /* Don't punish working computers */
 149                 if ((irqfixup == 2 && irq == 0) || action_ret == IRQ_NONE) {
 150                         int ok = misrouted_irq(irq);
 151                         if (action_ret == IRQ_NONE)
 152                                 desc->irqs_unhandled -= ok;
 153                 }
 154         }
 155
 156         desc->irq_count++;
 157         if (likely(desc->irq_count < 100000))
 158                 return;
 159
 160         desc->irq_count = 0;
 161         if (unlikely(desc->irqs_unhandled > 99900)) {
 162                 /*
 163                  * The interrupt is stuck
 164                  */
 165                 __report_bad_irq(irq, desc, action_ret);
 166                 /*
 167                  * Now kill the IRQ
 168                  */
 169                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 170                 desc->status |= IRQ_DISABLED;
 171                 desc->depth = 1;
 172                 desc->chip->disable(irq);
 173         }
 174         desc->irqs_unhandled = 0;
 175 }
 176
 177 int noirqdebug __read_mostly;
 178
 179 int noirqdebug_setup(char *str)
 180 {
 181         noirqdebug = 1;
 182         printk(KERN_INFO "IRQ lockup detection disabled\n");
 183
 184         return 1;
 185 }
 186
 187 __setup("noirqdebug", noirqdebug_setup);
 188
 189 static int __init irqfixup_setup(char *str)
 190 {
 191         irqfixup = 1;
 192         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 193         printk(KERN_WARNING "This may impact system performance.\n");
 194
 195         return 1;
 196 }
 197
 198 __setup("irqfixup", irqfixup_setup);
 199
 200 static int __init irqpoll_setup(char *str)
 201 {
 202         irqfixup = 2;
 203         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 204                                 "enabled\n");
 205         printk(KERN_WARNING "This may significantly impact system "
 206                                 "performance\n");
 207         return 1;
 208 }
 209
 210 __setup("irqpoll", irqpoll_setup);