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 static int irq_poll_cpu;
  25 static atomic_t irq_poll_active;
  26
  27 /*
  28  * We wait here for a poller to finish.
  29  *
  30  * If the poll runs on this CPU, then we yell loudly and return
  31  * false. That will leave the interrupt line disabled in the worst
  32  * case, but it should never happen.
  33  *
  34  * We wait until the poller is done and then recheck disabled and
  35  * action (about to be disabled). Only if it's still active, we return
  36  * true and let the handler run.
  37  */
  38 bool irq_wait_for_poll(struct irq_desc *desc)
  39 {
  40         if (WARN_ONCE(irq_poll_cpu == smp_processor_id(),
  41                       "irq poll in progress on cpu %d for irq %d\n",
  42                       smp_processor_id(), desc->irq_data.irq))
  43                 return false;
  44
  45 #ifdef CONFIG_SMP
  46         do {
  47                 raw_spin_unlock(&desc->lock);
  48                 while (irqd_irq_inprogress(&desc->irq_data))
  49                         cpu_relax();
  50                 raw_spin_lock(&desc->lock);
  51         } while (irqd_irq_inprogress(&desc->irq_data));
  52         /* Might have been disabled in meantime */
  53         return !irqd_irq_disabled(&desc->irq_data) && desc->action;
  54 #else
  55         return false;
  56 #endif
  57 }
  58
  59
  60 /*
  61  * Recovery handler for misrouted interrupts.
  62  */
  63 static int try_one_irq(int irq, struct irq_desc *desc, bool force)
  64 {
  65         irqreturn_t ret = IRQ_NONE;
  66         struct irqaction *action;
  67
  68         raw_spin_lock(&desc->lock);
  69
  70         /* PER_CPU and nested thread interrupts are never polled */
  71         if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc))
  72                 goto out;
  73
  74         /*
  75          * Do not poll disabled interrupts unless the spurious
  76          * disabled poller asks explicitely.
  77          */
  78         if (irqd_irq_disabled(&desc->irq_data) && !force)
  79                 goto out;
  80
  81         /*
  82          * All handlers must agree on IRQF_SHARED, so we test just the
  83          * first. Check for action->next as well.
  84          */
  85         action = desc->action;
  86         if (!action || !(action->flags & IRQF_SHARED) ||
  87             (action->flags & __IRQF_TIMER) || !action->next)
  88                 goto out;
  89
  90         /* Already running on another processor */
  91         if (irqd_irq_inprogress(&desc->irq_data)) {
  92                 /*
  93                  * Already running: If it is shared get the other
  94                  * CPU to go looking for our mystery interrupt too
  95                  */
  96                 desc->istate |= IRQS_PENDING;
  97                 goto out;
  98         }
  99
 100         /* Mark it poll in progress */
 101         desc->istate |= IRQS_POLL_INPROGRESS;
 102         do {
 103                 if (handle_irq_event(desc) == IRQ_HANDLED)
 104                         ret = IRQ_HANDLED;
 105                 action = desc->action;
 106         } while ((desc->istate & IRQS_PENDING) && action);
 107         desc->istate &= ~IRQS_POLL_INPROGRESS;
 108 out:
 109         raw_spin_unlock(&desc->lock);
 110         return ret == IRQ_HANDLED;
 111 }
 112
 113 static int misrouted_irq(int irq)
 114 {
 115         struct irq_desc *desc;
 116         int i, ok = 0;
 117
 118         if (atomic_inc_return(&irq_poll_active) == 1)
 119                 goto out;
 120
 121         irq_poll_cpu = smp_processor_id();
 122
 123         for_each_irq_desc(i, desc) {
 124                 if (!i)
 125                          continue;
 126
 127                 if (i == irq)   /* Already tried */
 128                         continue;
 129
 130                 if (try_one_irq(i, desc, false))
 131                         ok = 1;
 132         }
 133 out:
 134         atomic_dec(&irq_poll_active);
 135         /* So the caller can adjust the irq error counts */
 136         return ok;
 137 }
 138
 139 static void poll_spurious_irqs(unsigned long dummy)
 140 {
 141         struct irq_desc *desc;
 142         int i;
 143
 144         if (atomic_inc_return(&irq_poll_active) != 1)
 145                 goto out;
 146         irq_poll_cpu = smp_processor_id();
 147
 148         for_each_irq_desc(i, desc) {
 149                 unsigned int state;
 150
 151                 if (!i)
 152                          continue;
 153
 154                 /* Racy but it doesn't matter */
 155                 state = desc->istate;
 156                 barrier();
 157                 if (!(state & IRQS_SPURIOUS_DISABLED))
 158                         continue;
 159
 160                 local_irq_disable();
 161                 try_one_irq(i, desc, true);
 162                 local_irq_enable();
 163         }
 164 out:
 165         atomic_dec(&irq_poll_active);
 166         mod_timer(&poll_spurious_irq_timer,
 167                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 168 }
 169
 170 /*
 171  * If 99,900 of the previous 100,000 interrupts have not been handled
 172  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 173  * and try to turn the IRQ off.
 174  *
 175  * (The other 100-of-100,000 interrupts may have been a correctly
 176  *  functioning device sharing an IRQ with the failing one)
 177  */
 178 static void
 179 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 180                  irqreturn_t action_ret)
 181 {
 182         struct irqaction *action;
 183         unsigned long flags;
 184
 185         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 186                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 187                                 irq, action_ret);
 188         } else {
 189                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 190                                 "the \"irqpoll\" option)\n", irq);
 191         }
 192         dump_stack();
 193         printk(KERN_ERR "handlers:\n");
 194
 195         /*
 196          * We need to take desc->lock here. note_interrupt() is called
 197          * w/o desc->lock held, but IRQ_PROGRESS set. We might race
 198          * with something else removing an action. It's ok to take
 199          * desc->lock here. See synchronize_irq().
 200          */
 201         raw_spin_lock_irqsave(&desc->lock, flags);
 202         action = desc->action;
 203         while (action) {
 204                 printk(KERN_ERR "[<%p>]", action->handler);
 205                 print_symbol(" (%s)",
 206                         (unsigned long)action->handler);
 207                 printk("\n");
 208                 action = action->next;
 209         }
 210         raw_spin_unlock_irqrestore(&desc->lock, flags);
 211 }
 212
 213 static void
 214 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 215 {
 216         static int count = 100;
 217
 218         if (count > 0) {
 219                 count--;
 220                 __report_bad_irq(irq, desc, action_ret);
 221         }
 222 }
 223
 224 static inline int
 225 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 226                   irqreturn_t action_ret)
 227 {
 228         struct irqaction *action;
 229
 230         if (!irqfixup)
 231                 return 0;
 232
 233         /* We didn't actually handle the IRQ - see if it was misrouted? */
 234         if (action_ret == IRQ_NONE)
 235                 return 1;
 236
 237         /*
 238          * But for 'irqfixup == 2' we also do it for handled interrupts if
 239          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 240          * traditional PC timer interrupt.. Legacy)
 241          */
 242         if (irqfixup < 2)
 243                 return 0;
 244
 245         if (!irq)
 246                 return 1;
 247
 248         /*
 249          * Since we don't get the descriptor lock, "action" can
 250          * change under us.  We don't really care, but we don't
 251          * want to follow a NULL pointer. So tell the compiler to
 252          * just load it once by using a barrier.
 253          */
 254         action = desc->action;
 255         barrier();
 256         return action && (action->flags & IRQF_IRQPOLL);
 257 }
 258
 259 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 260                     irqreturn_t action_ret)
 261 {
 262         if (desc->istate & IRQS_POLL_INPROGRESS)
 263                 return;
 264
 265         if (unlikely(action_ret != IRQ_HANDLED)) {
 266                 /*
 267                  * If we are seeing only the odd spurious IRQ caused by
 268                  * bus asynchronicity then don't eventually trigger an error,
 269                  * otherwise the counter becomes a doomsday timer for otherwise
 270                  * working systems
 271                  */
 272                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 273                         desc->irqs_unhandled = 1;
 274                 else
 275                         desc->irqs_unhandled++;
 276                 desc->last_unhandled = jiffies;
 277                 if (unlikely(action_ret != IRQ_NONE))
 278                         report_bad_irq(irq, desc, action_ret);
 279         }
 280
 281         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 282                 int ok = misrouted_irq(irq);
 283                 if (action_ret == IRQ_NONE)
 284                         desc->irqs_unhandled -= ok;
 285         }
 286
 287         desc->irq_count++;
 288         if (likely(desc->irq_count < 100000))
 289                 return;
 290
 291         desc->irq_count = 0;
 292         if (unlikely(desc->irqs_unhandled > 99900)) {
 293                 /*
 294                  * The interrupt is stuck
 295                  */
 296                 __report_bad_irq(irq, desc, action_ret);
 297                 /*
 298                  * Now kill the IRQ
 299                  */
 300                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 301                 desc->istate |= IRQS_SPURIOUS_DISABLED;
 302                 desc->depth++;
 303                 irq_disable(desc);
 304
 305                 mod_timer(&poll_spurious_irq_timer,
 306                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 307         }
 308         desc->irqs_unhandled = 0;
 309 }
 310
 311 int noirqdebug __read_mostly;
 312
 313 int noirqdebug_setup(char *str)
 314 {
 315         noirqdebug = 1;
 316         printk(KERN_INFO "IRQ lockup detection disabled\n");
 317
 318         return 1;
 319 }
 320
 321 __setup("noirqdebug", noirqdebug_setup);
 322 module_param(noirqdebug, bool, 0644);
 323 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 324
 325 static int __init irqfixup_setup(char *str)
 326 {
 327         irqfixup = 1;
 328         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 329         printk(KERN_WARNING "This may impact system performance.\n");
 330
 331         return 1;
 332 }
 333
 334 __setup("irqfixup", irqfixup_setup);
 335 module_param(irqfixup, int, 0644);
 336
 337 static int __init irqpoll_setup(char *str)
 338 {
 339         irqfixup = 2;
 340         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 341                                 "enabled\n");
 342         printk(KERN_WARNING "This may significantly impact system "
 343                                 "performance\n");
 344         return 1;
 345 }
 346
 347 __setup("irqpoll", irqpoll_setup);