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 static inline int bad_action_ret(irqreturn_t action_ret)
 171 {
 172         if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
 173                 return 0;
 174         return 1;
 175 }
 176
 177 /*
 178  * If 99,900 of the previous 100,000 interrupts have not been handled
 179  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 180  * and try to turn the IRQ off.
 181  *
 182  * (The other 100-of-100,000 interrupts may have been a correctly
 183  *  functioning device sharing an IRQ with the failing one)
 184  */
 185 static void
 186 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 187                  irqreturn_t action_ret)
 188 {
 189         struct irqaction *action;
 190         unsigned long flags;
 191
 192         if (bad_action_ret(action_ret)) {
 193                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 194                                 irq, action_ret);
 195         } else {
 196                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 197                                 "the \"irqpoll\" option)\n", irq);
 198         }
 199         dump_stack();
 200         printk(KERN_ERR "handlers:\n");
 201
 202         /*
 203          * We need to take desc->lock here. note_interrupt() is called
 204          * w/o desc->lock held, but IRQ_PROGRESS set. We might race
 205          * with something else removing an action. It's ok to take
 206          * desc->lock here. See synchronize_irq().
 207          */
 208         raw_spin_lock_irqsave(&desc->lock, flags);
 209         action = desc->action;
 210         while (action) {
 211                 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
 212                 if (action->thread_fn)
 213                         printk(KERN_CONT " threaded [<%p>] %pf",
 214                                         action->thread_fn, action->thread_fn);
 215                 printk(KERN_CONT "\n");
 216                 action = action->next;
 217         }
 218         raw_spin_unlock_irqrestore(&desc->lock, flags);
 219 }
 220
 221 static void
 222 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 223 {
 224         static int count = 100;
 225
 226         if (count > 0) {
 227                 count--;
 228                 __report_bad_irq(irq, desc, action_ret);
 229         }
 230 }
 231
 232 static inline int
 233 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 234                   irqreturn_t action_ret)
 235 {
 236         struct irqaction *action;
 237
 238         if (!irqfixup)
 239                 return 0;
 240
 241         /* We didn't actually handle the IRQ - see if it was misrouted? */
 242         if (action_ret == IRQ_NONE)
 243                 return 1;
 244
 245         /*
 246          * But for 'irqfixup == 2' we also do it for handled interrupts if
 247          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 248          * traditional PC timer interrupt.. Legacy)
 249          */
 250         if (irqfixup < 2)
 251                 return 0;
 252
 253         if (!irq)
 254                 return 1;
 255
 256         /*
 257          * Since we don't get the descriptor lock, "action" can
 258          * change under us.  We don't really care, but we don't
 259          * want to follow a NULL pointer. So tell the compiler to
 260          * just load it once by using a barrier.
 261          */
 262         action = desc->action;
 263         barrier();
 264         return action && (action->flags & IRQF_IRQPOLL);
 265 }
 266
 267 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 268                     irqreturn_t action_ret)
 269 {
 270         if (desc->istate & IRQS_POLL_INPROGRESS)
 271                 return;
 272
 273         /* we get here again via the threaded handler */
 274         if (action_ret == IRQ_WAKE_THREAD)
 275                 return;
 276
 277         if (bad_action_ret(action_ret)) {
 278                 report_bad_irq(irq, desc, action_ret);
 279                 return;
 280         }
 281
 282         if (unlikely(action_ret == IRQ_NONE)) {
 283                 /*
 284                  * If we are seeing only the odd spurious IRQ caused by
 285                  * bus asynchronicity then don't eventually trigger an error,
 286                  * otherwise the counter becomes a doomsday timer for otherwise
 287                  * working systems
 288                  */
 289                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 290                         desc->irqs_unhandled = 1;
 291                 else
 292                         desc->irqs_unhandled++;
 293                 desc->last_unhandled = jiffies;
 294         }
 295
 296         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 297                 int ok = misrouted_irq(irq);
 298                 if (action_ret == IRQ_NONE)
 299                         desc->irqs_unhandled -= ok;
 300         }
 301
 302         desc->irq_count++;
 303         if (likely(desc->irq_count < 100000))
 304                 return;
 305
 306         desc->irq_count = 0;
 307         if (unlikely(desc->irqs_unhandled > 99900)) {
 308                 /*
 309                  * The interrupt is stuck
 310                  */
 311                 __report_bad_irq(irq, desc, action_ret);
 312                 /*
 313                  * Now kill the IRQ
 314                  */
 315                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 316                 desc->istate |= IRQS_SPURIOUS_DISABLED;
 317                 desc->depth++;
 318                 irq_disable(desc);
 319
 320                 mod_timer(&poll_spurious_irq_timer,
 321                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 322         }
 323         desc->irqs_unhandled = 0;
 324 }
 325
 326 int noirqdebug __read_mostly;
 327
 328 int noirqdebug_setup(char *str)
 329 {
 330         noirqdebug = 1;
 331         printk(KERN_INFO "IRQ lockup detection disabled\n");
 332
 333         return 1;
 334 }
 335
 336 __setup("noirqdebug", noirqdebug_setup);
 337 module_param(noirqdebug, bool, 0644);
 338 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 339
 340 static int __init irqfixup_setup(char *str)
 341 {
 342         irqfixup = 1;
 343         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 344         printk(KERN_WARNING "This may impact system performance.\n");
 345
 346         return 1;
 347 }
 348
 349 __setup("irqfixup", irqfixup_setup);
 350 module_param(irqfixup, int, 0644);
 351
 352 static int __init irqpoll_setup(char *str)
 353 {
 354         irqfixup = 2;
 355         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 356                                 "enabled\n");
 357         printk(KERN_WARNING "This may significantly impact system "
 358                                 "performance\n");
 359         return 1;
 360 }
 361
 362 __setup("irqpoll", irqpoll_setup);