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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 #include <linux/moduleparam.h>
  14
  15 static int irqfixup __read_mostly;
  16
  17 /*
  18  * Recovery handler for misrouted interrupts.
  19  */
  20 static int misrouted_irq(int irq)
  21 {
  22         int i;
  23         int ok = 0;
  24         int work = 0;   /* Did we do work for a real IRQ */
  25
  26         for (i = 1; i < NR_IRQS; i++) {
  27                 struct irq_desc *desc = irq_desc + i;
  28                 struct irqaction *action;
  29
  30                 if (i == irq)   /* Already tried */
  31                         continue;
  32
  33                 spin_lock(&desc->lock);
  34                 /* Already running on another processor */
  35                 if (desc->status & IRQ_INPROGRESS) {
  36                         /*
  37                          * Already running: If it is shared get the other
  38                          * CPU to go looking for our mystery interrupt too
  39                          */
  40                         if (desc->action && (desc->action->flags & IRQF_SHARED))
  41                                 desc->status |= IRQ_PENDING;
  42                         spin_unlock(&desc->lock);
  43                         continue;
  44                 }
  45                 /* Honour the normal IRQ locking */
  46                 desc->status |= IRQ_INPROGRESS;
  47                 action = desc->action;
  48                 spin_unlock(&desc->lock);
  49
  50                 while (action) {
  51                         /* Only shared IRQ handlers are safe to call */
  52                         if (action->flags & IRQF_SHARED) {
  53                                 if (action->handler(i, action->dev_id) ==
  54                                                 IRQ_HANDLED)
  55                                         ok = 1;
  56                         }
  57                         action = action->next;
  58                 }
  59                 local_irq_disable();
  60                 /* Now clean up the flags */
  61                 spin_lock(&desc->lock);
  62                 action = desc->action;
  63
  64                 /*
  65                  * While we were looking for a fixup someone queued a real
  66                  * IRQ clashing with our walk:
  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, 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 && desc->chip && desc->chip->end)
  84                         desc->chip->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, struct irq_desc *desc,
 104                  irqreturn_t action_ret)
 105 {
 106         struct irqaction *action;
 107
 108         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 109                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 110                                 irq, action_ret);
 111         } else {
 112                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 113                                 "the \"irqpoll\" option)\n", irq);
 114         }
 115         dump_stack();
 116         printk(KERN_ERR "handlers:\n");
 117
 118         action = desc->action;
 119         while (action) {
 120                 printk(KERN_ERR "[<%p>]", action->handler);
 121                 print_symbol(" (%s)",
 122                         (unsigned long)action->handler);
 123                 printk("\n");
 124                 action = action->next;
 125         }
 126 }
 127
 128 static void
 129 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 130 {
 131         static int count = 100;
 132
 133         if (count > 0) {
 134                 count--;
 135                 __report_bad_irq(irq, desc, action_ret);
 136         }
 137 }
 138
 139 static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 140 {
 141         struct irqaction *action;
 142
 143         if (!irqfixup)
 144                 return 0;
 145
 146         /* We didn't actually handle the IRQ - see if it was misrouted? */
 147         if (action_ret == IRQ_NONE)
 148                 return 1;
 149
 150         /*
 151          * But for 'irqfixup == 2' we also do it for handled interrupts if
 152          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 153          * traditional PC timer interrupt.. Legacy)
 154          */
 155         if (irqfixup < 2)
 156                 return 0;
 157
 158         if (!irq)
 159                 return 1;
 160
 161         /*
 162          * Since we don't get the descriptor lock, "action" can
 163          * change under us.  We don't really care, but we don't
 164          * want to follow a NULL pointer. So tell the compiler to
 165          * just load it once by using a barrier.
 166          */
 167         action = desc->action;
 168         barrier();
 169         return action && (action->flags & IRQF_IRQPOLL);
 170 }
 171
 172 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 173                     irqreturn_t action_ret)
 174 {
 175         if (unlikely(action_ret != IRQ_HANDLED)) {
 176                 /*
 177                  * If we are seeing only the odd spurious IRQ caused by
 178                  * bus asynchronicity then don't eventually trigger an error,
 179                  * otherwise the couter becomes a doomsday timer for otherwise
 180                  * working systems
 181                  */
 182                 if (jiffies - desc->last_unhandled > HZ/10)
 183                         desc->irqs_unhandled = 1;
 184                 else
 185                         desc->irqs_unhandled++;
 186                 desc->last_unhandled = jiffies;
 187                 if (unlikely(action_ret != IRQ_NONE))
 188                         report_bad_irq(irq, desc, action_ret);
 189         }
 190
 191         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 192                 int ok = misrouted_irq(irq);
 193                 if (action_ret == IRQ_NONE)
 194                         desc->irqs_unhandled -= ok;
 195         }
 196
 197         desc->irq_count++;
 198         if (likely(desc->irq_count < 100000))
 199                 return;
 200
 201         desc->irq_count = 0;
 202         if (unlikely(desc->irqs_unhandled > 99900)) {
 203                 /*
 204                  * The interrupt is stuck
 205                  */
 206                 __report_bad_irq(irq, desc, action_ret);
 207                 /*
 208                  * Now kill the IRQ
 209                  */
 210                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 211                 desc->status |= IRQ_DISABLED;
 212                 desc->depth = 1;
 213                 desc->chip->disable(irq);
 214         }
 215         desc->irqs_unhandled = 0;
 216 }
 217
 218 int noirqdebug __read_mostly;
 219
 220 int noirqdebug_setup(char *str)
 221 {
 222         noirqdebug = 1;
 223         printk(KERN_INFO "IRQ lockup detection disabled\n");
 224
 225         return 1;
 226 }
 227
 228 __setup("noirqdebug", noirqdebug_setup);
 229 module_param(noirqdebug, bool, 0644);
 230 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 231
 232 static int __init irqfixup_setup(char *str)
 233 {
 234         irqfixup = 1;
 235         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 236         printk(KERN_WARNING "This may impact system performance.\n");
 237
 238         return 1;
 239 }
 240
 241 __setup("irqfixup", irqfixup_setup);
 242 module_param(irqfixup, int, 0644);
 243 MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");
 244
 245 static int __init irqpoll_setup(char *str)
 246 {
 247         irqfixup = 2;
 248         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 249                                 "enabled\n");
 250         printk(KERN_WARNING "This may significantly impact system "
 251                                 "performance\n");
 252         return 1;
 253 }
 254
 255 __setup("irqpoll", irqpoll_setup);