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/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 #include <linux/timer.h>
  16
  17 static int irqfixup __read_mostly;
  18
  19 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
  20 static void poll_spurious_irqs(unsigned long dummy);
  21 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
  22
  23 /*
  24  * Recovery handler for misrouted interrupts.
  25  */
  26 static int try_one_irq(int irq, struct irq_desc *desc)
  27 {
  28         struct irqaction *action;
  29         int ok = 0;
  30         int work = 0;   /* Did we do work for a real IRQ */
  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                 return ok;
  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(irq, 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(irq, 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(irq);
  84         spin_unlock(&desc->lock);
  85
  86         return ok;
  87 }
  88
  89 static int misrouted_irq(int irq)
  90 {
  91         int i;
  92         int ok = 0;
  93         struct irq_desc *desc;
  94
  95         for_each_irq_desc(i, desc) {
  96                 if (!i)
  97                          continue;
  98
  99                 if (i == irq)   /* Already tried */
 100                         continue;
 101
 102                 if (try_one_irq(i, desc))
 103                         ok = 1;
 104         }
 105         /* So the caller can adjust the irq error counts */
 106         return ok;
 107 }
 108
 109 static void poll_spurious_irqs(unsigned long dummy)
 110 {
 111         int i;
 112         struct irq_desc *desc;
 113
 114         for_each_irq_desc(i, desc) {
 115                 unsigned int status;
 116
 117                 if (!i)
 118                          continue;
 119
 120                 /* Racy but it doesn't matter */
 121                 status = desc->status;
 122                 barrier();
 123                 if (!(status & IRQ_SPURIOUS_DISABLED))
 124                         continue;
 125
 126                 try_one_irq(i, desc);
 127         }
 128
 129         mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 130 }
 131
 132 /*
 133  * If 99,900 of the previous 100,000 interrupts have not been handled
 134  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 135  * and try to turn the IRQ off.
 136  *
 137  * (The other 100-of-100,000 interrupts may have been a correctly
 138  *  functioning device sharing an IRQ with the failing one)
 139  *
 140  * Called under desc->lock
 141  */
 142
 143 static void
 144 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 145                  irqreturn_t action_ret)
 146 {
 147         struct irqaction *action;
 148
 149         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 150                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 151                                 irq, action_ret);
 152         } else {
 153                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 154                                 "the \"irqpoll\" option)\n", irq);
 155         }
 156         dump_stack();
 157         printk(KERN_ERR "handlers:\n");
 158
 159         action = desc->action;
 160         while (action) {
 161                 printk(KERN_ERR "[<%p>]", action->handler);
 162                 print_symbol(" (%s)",
 163                         (unsigned long)action->handler);
 164                 printk("\n");
 165                 action = action->next;
 166         }
 167 }
 168
 169 static void
 170 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 171 {
 172         static int count = 100;
 173
 174         if (count > 0) {
 175                 count--;
 176                 __report_bad_irq(irq, desc, action_ret);
 177         }
 178 }
 179
 180 static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 181 {
 182         struct irqaction *action;
 183
 184         if (!irqfixup)
 185                 return 0;
 186
 187         /* We didn't actually handle the IRQ - see if it was misrouted? */
 188         if (action_ret == IRQ_NONE)
 189                 return 1;
 190
 191         /*
 192          * But for 'irqfixup == 2' we also do it for handled interrupts if
 193          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 194          * traditional PC timer interrupt.. Legacy)
 195          */
 196         if (irqfixup < 2)
 197                 return 0;
 198
 199         if (!irq)
 200                 return 1;
 201
 202         /*
 203          * Since we don't get the descriptor lock, "action" can
 204          * change under us.  We don't really care, but we don't
 205          * want to follow a NULL pointer. So tell the compiler to
 206          * just load it once by using a barrier.
 207          */
 208         action = desc->action;
 209         barrier();
 210         return action && (action->flags & IRQF_IRQPOLL);
 211 }
 212
 213 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 214                     irqreturn_t action_ret)
 215 {
 216         if (unlikely(action_ret != IRQ_HANDLED)) {
 217                 /*
 218                  * If we are seeing only the odd spurious IRQ caused by
 219                  * bus asynchronicity then don't eventually trigger an error,
 220                  * otherwise the couter becomes a doomsday timer for otherwise
 221                  * working systems
 222                  */
 223                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 224                         desc->irqs_unhandled = 1;
 225                 else
 226                         desc->irqs_unhandled++;
 227                 desc->last_unhandled = jiffies;
 228                 if (unlikely(action_ret != IRQ_NONE))
 229                         report_bad_irq(irq, desc, action_ret);
 230         }
 231
 232         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 233                 int ok = misrouted_irq(irq);
 234                 if (action_ret == IRQ_NONE)
 235                         desc->irqs_unhandled -= ok;
 236         }
 237
 238         desc->irq_count++;
 239         if (likely(desc->irq_count < 100000))
 240                 return;
 241
 242         desc->irq_count = 0;
 243         if (unlikely(desc->irqs_unhandled > 99900)) {
 244                 /*
 245                  * The interrupt is stuck
 246                  */
 247                 __report_bad_irq(irq, desc, action_ret);
 248                 /*
 249                  * Now kill the IRQ
 250                  */
 251                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 252                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
 253                 desc->depth++;
 254                 desc->chip->disable(irq);
 255
 256                 mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 257         }
 258         desc->irqs_unhandled = 0;
 259 }
 260
 261 int noirqdebug __read_mostly;
 262
 263 int noirqdebug_setup(char *str)
 264 {
 265         noirqdebug = 1;
 266         printk(KERN_INFO "IRQ lockup detection disabled\n");
 267
 268         return 1;
 269 }
 270
 271 __setup("noirqdebug", noirqdebug_setup);
 272 module_param(noirqdebug, bool, 0644);
 273 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 274
 275 static int __init irqfixup_setup(char *str)
 276 {
 277         irqfixup = 1;
 278         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 279         printk(KERN_WARNING "This may impact system performance.\n");
 280
 281         return 1;
 282 }
 283
 284 __setup("irqfixup", irqfixup_setup);
 285 module_param(irqfixup, int, 0644);
 286 MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode, 2: irqpoll mode");
 287
 288 static int __init irqpoll_setup(char *str)
 289 {
 290         irqfixup = 2;
 291         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 292                                 "enabled\n");
 293         printk(KERN_WARNING "This may significantly impact system "
 294                                 "performance\n");
 295         return 1;
 296 }
 297
 298 __setup("irqpoll", irqpoll_setup);