SAFE public projects git trees. - safe/jmp/linux-2.6/blob - kernel/irq/spurious.c

   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, struct pt_regs *regs)
  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 & SA_SHIRQ))
  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 & 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                 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, regs, 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)
  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, irq_desc_t *desc, irqreturn_t action_ret)
 103 {
 104         struct irqaction *action;
 105
 106         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 107                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 108                                 irq, action_ret);
 109         } else {
 110                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 111                                 "the \"irqpoll\" option)\n", irq);
 112         }
 113         dump_stack();
 114         printk(KERN_ERR "handlers:\n");
 115
 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
 127 report_bad_irq(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret)
 128 {
 129         static int count = 100;
 130
 131         if (count > 0) {
 132                 count--;
 133                 __report_bad_irq(irq, desc, action_ret);
 134         }
 135 }
 136
 137 void note_interrupt(unsigned int irq, irq_desc_t *desc, irqreturn_t action_ret,
 138                     struct pt_regs *regs)
 139 {
 140         if (unlikely(action_ret != IRQ_HANDLED)) {
 141                 desc->irqs_unhandled++;
 142                 if (unlikely(action_ret != IRQ_NONE))
 143                         report_bad_irq(irq, desc, action_ret);
 144         }
 145
 146         if (unlikely(irqfixup)) {
 147                 /* Don't punish working computers */
 148                 if ((irqfixup == 2 && irq == 0) || action_ret == IRQ_NONE) {
 149                         int ok = misrouted_irq(irq, regs);
 150                         if (action_ret == IRQ_NONE)
 151                                 desc->irqs_unhandled -= ok;
 152                 }
 153         }
 154
 155         desc->irq_count++;
 156         if (likely(desc->irq_count < 100000))
 157                 return;
 158
 159         desc->irq_count = 0;
 160         if (unlikely(desc->irqs_unhandled > 99900)) {
 161                 /*
 162                  * The interrupt is stuck
 163                  */
 164                 __report_bad_irq(irq, desc, action_ret);
 165                 /*
 166                  * Now kill the IRQ
 167                  */
 168                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 169                 desc->status |= IRQ_DISABLED;
 170                 desc->chip->disable(irq);
 171         }
 172         desc->irqs_unhandled = 0;
 173 }
 174
 175 int noirqdebug __read_mostly;
 176
 177 int __init noirqdebug_setup(char *str)
 178 {
 179         noirqdebug = 1;
 180         printk(KERN_INFO "IRQ lockup detection disabled\n");
 181
 182         return 1;
 183 }
 184
 185 __setup("noirqdebug", noirqdebug_setup);
 186
 187 static int __init irqfixup_setup(char *str)
 188 {
 189         irqfixup = 1;
 190         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 191         printk(KERN_WARNING "This may impact system performance.\n");
 192
 193         return 1;
 194 }
 195
 196 __setup("irqfixup", irqfixup_setup);
 197
 198 static int __init irqpoll_setup(char *str)
 199 {
 200         irqfixup = 2;
 201         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 202                                 "enabled\n");
 203         printk(KERN_WARNING "This may significantly impact system "
 204                                 "performance\n");
 205         return 1;
 206 }
 207
 208 __setup("irqpoll", irqpoll_setup);