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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/jiffies.h>
  10 #include <linux/irq.h>
  11 #include <linux/module.h>
  12 #include <linux/kallsyms.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/moduleparam.h>
  15
  16 static int irqfixup __read_mostly;
  17
  18 /*
  19  * Recovery handler for misrouted interrupts.
  20  */
  21 static int misrouted_irq(int irq)
  22 {
  23         int i;
  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 irq_desc *desc = irq_desc + i;
  29                 struct irqaction *action;
  30
  31                 if (i == irq)   /* Already tried */
  32                         continue;
  33
  34                 spin_lock(&desc->lock);
  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 & IRQF_SHARED))
  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                 action = desc->action;
  49                 spin_unlock(&desc->lock);
  50
  51                 while (action) {
  52                         /* Only shared IRQ handlers are safe to call */
  53                         if (action->flags & IRQF_SHARED) {
  54                                 if (action->handler(i, action->dev_id) ==
  55                                                 IRQ_HANDLED)
  56                                         ok = 1;
  57                         }
  58                         action = action->next;
  59                 }
  60                 local_irq_disable();
  61                 /* Now clean up the flags */
  62                 spin_lock(&desc->lock);
  63                 action = desc->action;
  64
  65                 /*
  66                  * While we were looking for a fixup someone queued a real
  67                  * IRQ clashing with our walk:
  68                  */
  69                 while ((desc->status & IRQ_PENDING) && action) {
  70                         /*
  71                          * Perform real IRQ processing for the IRQ we deferred
  72                          */
  73                         work = 1;
  74                         spin_unlock(&desc->lock);
  75                         handle_IRQ_event(i, action);
  76                         spin_lock(&desc->lock);
  77                         desc->status &= ~IRQ_PENDING;
  78                 }
  79                 desc->status &= ~IRQ_INPROGRESS;
  80                 /*
  81                  * If we did actual work for the real IRQ line we must let the
  82                  * IRQ controller clean up too
  83                  */
  84                 if (work && desc->chip && desc->chip->end)
  85                         desc->chip->end(i);
  86                 spin_unlock(&desc->lock);
  87         }
  88         /* So the caller can adjust the irq error counts */
  89         return ok;
  90 }
  91
  92 /*
  93  * If 99,900 of the previous 100,000 interrupts have not been handled
  94  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
  95  * and try to turn the IRQ off.
  96  *
  97  * (The other 100-of-100,000 interrupts may have been a correctly
  98  *  functioning device sharing an IRQ with the failing one)
  99  *
 100  * Called under desc->lock
 101  */
 102
 103 static void
 104 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 105                  irqreturn_t action_ret)
 106 {
 107         struct irqaction *action;
 108
 109         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 110                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 111                                 irq, action_ret);
 112         } else {
 113                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 114                                 "the \"irqpoll\" option)\n", irq);
 115         }
 116         dump_stack();
 117         printk(KERN_ERR "handlers:\n");
 118
 119         action = desc->action;
 120         while (action) {
 121                 printk(KERN_ERR "[<%p>]", action->handler);
 122                 print_symbol(" (%s)",
 123                         (unsigned long)action->handler);
 124                 printk("\n");
 125                 action = action->next;
 126         }
 127 }
 128
 129 static void
 130 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 131 {
 132         static int count = 100;
 133
 134         if (count > 0) {
 135                 count--;
 136                 __report_bad_irq(irq, desc, action_ret);
 137         }
 138 }
 139
 140 static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 141 {
 142         struct irqaction *action;
 143
 144         if (!irqfixup)
 145                 return 0;
 146
 147         /* We didn't actually handle the IRQ - see if it was misrouted? */
 148         if (action_ret == IRQ_NONE)
 149                 return 1;
 150
 151         /*
 152          * But for 'irqfixup == 2' we also do it for handled interrupts if
 153          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 154          * traditional PC timer interrupt.. Legacy)
 155          */
 156         if (irqfixup < 2)
 157                 return 0;
 158
 159         if (!irq)
 160                 return 1;
 161
 162         /*
 163          * Since we don't get the descriptor lock, "action" can
 164          * change under us.  We don't really care, but we don't
 165          * want to follow a NULL pointer. So tell the compiler to
 166          * just load it once by using a barrier.
 167          */
 168         action = desc->action;
 169         barrier();
 170         return action && (action->flags & IRQF_IRQPOLL);
 171 }
 172
 173 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 174                     irqreturn_t action_ret)
 175 {
 176         if (unlikely(action_ret != IRQ_HANDLED)) {
 177                 /*
 178                  * If we are seeing only the odd spurious IRQ caused by
 179                  * bus asynchronicity then don't eventually trigger an error,
 180                  * otherwise the couter becomes a doomsday timer for otherwise
 181                  * working systems
 182                  */
 183                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 184                         desc->irqs_unhandled = 1;
 185                 else
 186                         desc->irqs_unhandled++;
 187                 desc->last_unhandled = jiffies;
 188                 if (unlikely(action_ret != IRQ_NONE))
 189                         report_bad_irq(irq, desc, action_ret);
 190         }
 191
 192         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 193                 int ok = misrouted_irq(irq);
 194                 if (action_ret == IRQ_NONE)
 195                         desc->irqs_unhandled -= ok;
 196         }
 197
 198         desc->irq_count++;
 199         if (likely(desc->irq_count < 100000))
 200                 return;
 201
 202         desc->irq_count = 0;
 203         if (unlikely(desc->irqs_unhandled > 99900)) {
 204                 /*
 205                  * The interrupt is stuck
 206                  */
 207                 __report_bad_irq(irq, desc, action_ret);
 208                 /*
 209                  * Now kill the IRQ
 210                  */
 211                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 212                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
 213                 desc->depth++;
 214                 desc->chip->disable(irq);
 215         }
 216         desc->irqs_unhandled = 0;
 217 }
 218
 219 int noirqdebug __read_mostly;
 220
 221 int noirqdebug_setup(char *str)
 222 {
 223         noirqdebug = 1;
 224         printk(KERN_INFO "IRQ lockup detection disabled\n");
 225
 226         return 1;
 227 }
 228
 229 __setup("noirqdebug", noirqdebug_setup);
 230 module_param(noirqdebug, bool, 0644);
 231 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 232
 233 static int __init irqfixup_setup(char *str)
 234 {
 235         irqfixup = 1;
 236         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 237         printk(KERN_WARNING "This may impact system performance.\n");
 238
 239         return 1;
 240 }
 241
 242 __setup("irqfixup", irqfixup_setup);
 243 module_param(irqfixup, int, 0644);
 244 MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");
 245
 246 static int __init irqpoll_setup(char *str)
 247 {
 248         irqfixup = 2;
 249         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 250                                 "enabled\n");
 251         printk(KERN_WARNING "This may significantly impact system "
 252                                 "performance\n");
 253         return 1;
 254 }
 255
 256 __setup("irqpoll", irqpoll_setup);