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)
  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 static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 139 {
 140         struct irqaction *action;
 141
 142         if (!irqfixup)
 143                 return 0;
 144
 145         /* We didn't actually handle the IRQ - see if it was misrouted? */
 146         if (action_ret == IRQ_NONE)
 147                 return 1;
 148
 149         /*
 150          * But for 'irqfixup == 2' we also do it for handled interrupts if
 151          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 152          * traditional PC timer interrupt.. Legacy)
 153          */
 154         if (irqfixup < 2)
 155                 return 0;
 156
 157         if (!irq)
 158                 return 1;
 159
 160         /*
 161          * Since we don't get the descriptor lock, "action" can
 162          * change under us.  We don't really care, but we don't
 163          * want to follow a NULL pointer. So tell the compiler to
 164          * just load it once by using a barrier.
 165          */
 166         action = desc->action;
 167         barrier();
 168         return action && (action->flags & IRQF_IRQPOLL);
 169 }
 170
 171 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 172                     irqreturn_t action_ret)
 173 {
 174         if (unlikely(action_ret != IRQ_HANDLED)) {
 175                 /*
 176                  * If we are seeing only the odd spurious IRQ caused by
 177                  * bus asynchronicity then don't eventually trigger an error,
 178                  * otherwise the couter becomes a doomsday timer for otherwise
 179                  * working systems
 180                  */
 181                 if (jiffies - desc->last_unhandled > HZ/10)
 182                         desc->irqs_unhandled = 1;
 183                 else
 184                         desc->irqs_unhandled++;
 185                 desc->last_unhandled = jiffies;
 186                 if (unlikely(action_ret != IRQ_NONE))
 187                         report_bad_irq(irq, desc, action_ret);
 188         }
 189
 190         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 191                 int ok = misrouted_irq(irq);
 192                 if (action_ret == IRQ_NONE)
 193                         desc->irqs_unhandled -= ok;
 194         }
 195
 196         desc->irq_count++;
 197         if (likely(desc->irq_count < 100000))
 198                 return;
 199
 200         desc->irq_count = 0;
 201         if (unlikely(desc->irqs_unhandled > 99900)) {
 202                 /*
 203                  * The interrupt is stuck
 204                  */
 205                 __report_bad_irq(irq, desc, action_ret);
 206                 /*
 207                  * Now kill the IRQ
 208                  */
 209                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 210                 desc->status |= IRQ_DISABLED;
 211                 desc->depth = 1;
 212                 desc->chip->disable(irq);
 213         }
 214         desc->irqs_unhandled = 0;
 215 }
 216
 217 int noirqdebug __read_mostly;
 218
 219 int noirqdebug_setup(char *str)
 220 {
 221         noirqdebug = 1;
 222         printk(KERN_INFO "IRQ lockup detection disabled\n");
 223
 224         return 1;
 225 }
 226
 227 __setup("noirqdebug", noirqdebug_setup);
 228
 229 static int __init irqfixup_setup(char *str)
 230 {
 231         irqfixup = 1;
 232         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 233         printk(KERN_WARNING "This may impact system performance.\n");
 234
 235         return 1;
 236 }
 237
 238 __setup("irqfixup", irqfixup_setup);
 239
 240 static int __init irqpoll_setup(char *str)
 241 {
 242         irqfixup = 2;
 243         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 244                                 "enabled\n");
 245         printk(KERN_WARNING "This may significantly impact system "
 246                                 "performance\n");
 247         return 1;
 248 }
 249
 250 __setup("irqpoll", irqpoll_setup);