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 #include "internals.h"
  18
  19 static int irqfixup __read_mostly;
  20
  21 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
  22 static void poll_spurious_irqs(unsigned long dummy);
  23 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
  24
  25 /*
  26  * Recovery handler for misrouted interrupts.
  27  */
  28 static int try_one_irq(int irq, struct irq_desc *desc)
  29 {
  30         struct irqaction *action;
  31         int ok = 0, work = 0;
  32
  33         raw_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                 raw_spin_unlock(&desc->lock);
  43                 return ok;
  44         }
  45         /* Honour the normal IRQ locking */
  46         desc->status |= IRQ_INPROGRESS;
  47         action = desc->action;
  48         raw_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(irq, 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         raw_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                 raw_spin_unlock(&desc->lock);
  74                 handle_IRQ_event(irq, action);
  75                 raw_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)
  84                 irq_end(irq, desc);
  85         raw_spin_unlock(&desc->lock);
  86
  87         return ok;
  88 }
  89
  90 static int misrouted_irq(int irq)
  91 {
  92         struct irq_desc *desc;
  93         int i, ok = 0;
  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         struct irq_desc *desc;
 112         int i;
 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                 local_irq_disable();
 127                 try_one_irq(i, desc);
 128                 local_irq_enable();
 129         }
 130
 131         mod_timer(&poll_spurious_irq_timer,
 132                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 133 }
 134
 135 /*
 136  * If 99,900 of the previous 100,000 interrupts have not been handled
 137  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 138  * and try to turn the IRQ off.
 139  *
 140  * (The other 100-of-100,000 interrupts may have been a correctly
 141  *  functioning device sharing an IRQ with the failing one)
 142  *
 143  * Called under desc->lock
 144  */
 145
 146 static void
 147 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 148                  irqreturn_t action_ret)
 149 {
 150         struct irqaction *action;
 151
 152         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 153                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 154                                 irq, action_ret);
 155         } else {
 156                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 157                                 "the \"irqpoll\" option)\n", irq);
 158         }
 159         dump_stack();
 160         printk(KERN_ERR "handlers:\n");
 161
 162         action = desc->action;
 163         while (action) {
 164                 printk(KERN_ERR "[<%p>]", action->handler);
 165                 print_symbol(" (%s)",
 166                         (unsigned long)action->handler);
 167                 printk("\n");
 168                 action = action->next;
 169         }
 170 }
 171
 172 static void
 173 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 174 {
 175         static int count = 100;
 176
 177         if (count > 0) {
 178                 count--;
 179                 __report_bad_irq(irq, desc, action_ret);
 180         }
 181 }
 182
 183 static inline int
 184 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 185                   irqreturn_t action_ret)
 186 {
 187         struct irqaction *action;
 188
 189         if (!irqfixup)
 190                 return 0;
 191
 192         /* We didn't actually handle the IRQ - see if it was misrouted? */
 193         if (action_ret == IRQ_NONE)
 194                 return 1;
 195
 196         /*
 197          * But for 'irqfixup == 2' we also do it for handled interrupts if
 198          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 199          * traditional PC timer interrupt.. Legacy)
 200          */
 201         if (irqfixup < 2)
 202                 return 0;
 203
 204         if (!irq)
 205                 return 1;
 206
 207         /*
 208          * Since we don't get the descriptor lock, "action" can
 209          * change under us.  We don't really care, but we don't
 210          * want to follow a NULL pointer. So tell the compiler to
 211          * just load it once by using a barrier.
 212          */
 213         action = desc->action;
 214         barrier();
 215         return action && (action->flags & IRQF_IRQPOLL);
 216 }
 217
 218 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 219                     irqreturn_t action_ret)
 220 {
 221         if (unlikely(action_ret != IRQ_HANDLED)) {
 222                 /*
 223                  * If we are seeing only the odd spurious IRQ caused by
 224                  * bus asynchronicity then don't eventually trigger an error,
 225                  * otherwise the counter becomes a doomsday timer for otherwise
 226                  * working systems
 227                  */
 228                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 229                         desc->irqs_unhandled = 1;
 230                 else
 231                         desc->irqs_unhandled++;
 232                 desc->last_unhandled = jiffies;
 233                 if (unlikely(action_ret != IRQ_NONE))
 234                         report_bad_irq(irq, desc, action_ret);
 235         }
 236
 237         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 238                 int ok = misrouted_irq(irq);
 239                 if (action_ret == IRQ_NONE)
 240                         desc->irqs_unhandled -= ok;
 241         }
 242
 243         desc->irq_count++;
 244         if (likely(desc->irq_count < 100000))
 245                 return;
 246
 247         desc->irq_count = 0;
 248         if (unlikely(desc->irqs_unhandled > 99900)) {
 249                 /*
 250                  * The interrupt is stuck
 251                  */
 252                 __report_bad_irq(irq, desc, action_ret);
 253                 /*
 254                  * Now kill the IRQ
 255                  */
 256                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 257                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
 258                 desc->depth++;
 259                 desc->irq_data.chip->irq_disable(&desc->irq_data);
 260
 261                 mod_timer(&poll_spurious_irq_timer,
 262                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 263         }
 264         desc->irqs_unhandled = 0;
 265 }
 266
 267 int noirqdebug __read_mostly;
 268
 269 int noirqdebug_setup(char *str)
 270 {
 271         noirqdebug = 1;
 272         printk(KERN_INFO "IRQ lockup detection disabled\n");
 273
 274         return 1;
 275 }
 276
 277 __setup("noirqdebug", noirqdebug_setup);
 278 module_param(noirqdebug, bool, 0644);
 279 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 280
 281 static int __init irqfixup_setup(char *str)
 282 {
 283         irqfixup = 1;
 284         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 285         printk(KERN_WARNING "This may impact system performance.\n");
 286
 287         return 1;
 288 }
 289
 290 __setup("irqfixup", irqfixup_setup);
 291 module_param(irqfixup, int, 0644);
 292
 293 static int __init irqpoll_setup(char *str)
 294 {
 295         irqfixup = 2;
 296         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 297                                 "enabled\n");
 298         printk(KERN_WARNING "This may significantly impact system "
 299                                 "performance\n");
 300         return 1;
 301 }
 302
 303 __setup("irqpoll", irqpoll_setup);