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         /*
  71          * PER_CPU, nested thread interrupts and interrupts explicitely
  72          * marked polled are excluded from polling.
  73          */
  74         if (irq_settings_is_per_cpu(desc) ||
  75             irq_settings_is_nested_thread(desc) ||
  76             irq_settings_is_polled(desc))
  77                 goto out;
  78
  79         /*
  80          * Do not poll disabled interrupts unless the spurious
  81          * disabled poller asks explicitely.
  82          */
  83         if (irqd_irq_disabled(&desc->irq_data) && !force)
  84                 goto out;
  85
  86         /*
  87          * All handlers must agree on IRQF_SHARED, so we test just the
  88          * first.
  89          */
  90         action = desc->action;
  91         if (!action || !(action->flags & IRQF_SHARED) ||
  92             (action->flags & __IRQF_TIMER))
  93                 goto out;
  94
  95         /* Already running on another processor */
  96         if (irqd_irq_inprogress(&desc->irq_data)) {
  97                 /*
  98                  * Already running: If it is shared get the other
  99                  * CPU to go looking for our mystery interrupt too
 100                  */
 101                 desc->istate |= IRQS_PENDING;
 102                 goto out;
 103         }
 104
 105         /* Mark it poll in progress */
 106         desc->istate |= IRQS_POLL_INPROGRESS;
 107         do {
 108                 if (handle_irq_event(desc) == IRQ_HANDLED)
 109                         ret = IRQ_HANDLED;
 110                 /* Make sure that there is still a valid action */
 111                 action = desc->action;
 112         } while ((desc->istate & IRQS_PENDING) && action);
 113         desc->istate &= ~IRQS_POLL_INPROGRESS;
 114 out:
 115         raw_spin_unlock(&desc->lock);
 116         return ret == IRQ_HANDLED;
 117 }
 118
 119 static int misrouted_irq(int irq)
 120 {
 121         struct irq_desc *desc;
 122         int i, ok = 0;
 123
 124         if (atomic_inc_return(&irq_poll_active) != 1)
 125                 goto out;
 126
 127         irq_poll_cpu = smp_processor_id();
 128
 129         for_each_irq_desc(i, desc) {
 130                 if (!i)
 131                          continue;
 132
 133                 if (i == irq)   /* Already tried */
 134                         continue;
 135
 136                 if (try_one_irq(i, desc, false))
 137                         ok = 1;
 138         }
 139 out:
 140         atomic_dec(&irq_poll_active);
 141         /* So the caller can adjust the irq error counts */
 142         return ok;
 143 }
 144
 145 static void poll_spurious_irqs(unsigned long dummy)
 146 {
 147         struct irq_desc *desc;
 148         int i;
 149
 150         if (atomic_inc_return(&irq_poll_active) != 1)
 151                 goto out;
 152         irq_poll_cpu = smp_processor_id();
 153
 154         for_each_irq_desc(i, desc) {
 155                 unsigned int state;
 156
 157                 if (!i)
 158                          continue;
 159
 160                 /* Racy but it doesn't matter */
 161                 state = desc->istate;
 162                 barrier();
 163                 if (!(state & IRQS_SPURIOUS_DISABLED))
 164                         continue;
 165
 166                 local_irq_disable();
 167                 try_one_irq(i, desc, true);
 168                 local_irq_enable();
 169         }
 170 out:
 171         atomic_dec(&irq_poll_active);
 172         mod_timer(&poll_spurious_irq_timer,
 173                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 174 }
 175
 176 static inline int bad_action_ret(irqreturn_t action_ret)
 177 {
 178         if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD)))
 179                 return 0;
 180         return 1;
 181 }
 182
 183 /*
 184  * If 99,900 of the previous 100,000 interrupts have not been handled
 185  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 186  * and try to turn the IRQ off.
 187  *
 188  * (The other 100-of-100,000 interrupts may have been a correctly
 189  *  functioning device sharing an IRQ with the failing one)
 190  */
 191 static void
 192 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 193                  irqreturn_t action_ret)
 194 {
 195         struct irqaction *action;
 196         unsigned long flags;
 197
 198         if (bad_action_ret(action_ret)) {
 199                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 200                                 irq, action_ret);
 201         } else {
 202                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 203                                 "the \"irqpoll\" option)\n", irq);
 204         }
 205         dump_stack();
 206         printk(KERN_ERR "handlers:\n");
 207
 208         /*
 209          * We need to take desc->lock here. note_interrupt() is called
 210          * w/o desc->lock held, but IRQ_PROGRESS set. We might race
 211          * with something else removing an action. It's ok to take
 212          * desc->lock here. See synchronize_irq().
 213          */
 214         raw_spin_lock_irqsave(&desc->lock, flags);
 215         action = desc->action;
 216         while (action) {
 217                 printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
 218                 if (action->thread_fn)
 219                         printk(KERN_CONT " threaded [<%p>] %pf",
 220                                         action->thread_fn, action->thread_fn);
 221                 printk(KERN_CONT "\n");
 222                 action = action->next;
 223         }
 224         raw_spin_unlock_irqrestore(&desc->lock, flags);
 225 }
 226
 227 static void
 228 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 229 {
 230         static int count = 100;
 231
 232         if (count > 0) {
 233                 count--;
 234                 __report_bad_irq(irq, desc, action_ret);
 235         }
 236 }
 237
 238 static inline int
 239 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 240                   irqreturn_t action_ret)
 241 {
 242         struct irqaction *action;
 243
 244         if (!irqfixup)
 245                 return 0;
 246
 247         /* We didn't actually handle the IRQ - see if it was misrouted? */
 248         if (action_ret == IRQ_NONE)
 249                 return 1;
 250
 251         /*
 252          * But for 'irqfixup == 2' we also do it for handled interrupts if
 253          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 254          * traditional PC timer interrupt.. Legacy)
 255          */
 256         if (irqfixup < 2)
 257                 return 0;
 258
 259         if (!irq)
 260                 return 1;
 261
 262         /*
 263          * Since we don't get the descriptor lock, "action" can
 264          * change under us.  We don't really care, but we don't
 265          * want to follow a NULL pointer. So tell the compiler to
 266          * just load it once by using a barrier.
 267          */
 268         action = desc->action;
 269         barrier();
 270         return action && (action->flags & IRQF_IRQPOLL);
 271 }
 272
 273 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 274                     irqreturn_t action_ret)
 275 {
 276         if (desc->istate & IRQS_POLL_INPROGRESS ||
 277             irq_settings_is_polled(desc))
 278                 return;
 279
 280         /* we get here again via the threaded handler */
 281         if (action_ret == IRQ_WAKE_THREAD)
 282                 return;
 283
 284         if (bad_action_ret(action_ret)) {
 285                 report_bad_irq(irq, desc, action_ret);
 286                 return;
 287         }
 288
 289         if (unlikely(action_ret == IRQ_NONE)) {
 290                 /*
 291                  * If we are seeing only the odd spurious IRQ caused by
 292                  * bus asynchronicity then don't eventually trigger an error,
 293                  * otherwise the counter becomes a doomsday timer for otherwise
 294                  * working systems
 295                  */
 296                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 297                         desc->irqs_unhandled = 1;
 298                 else
 299                         desc->irqs_unhandled++;
 300                 desc->last_unhandled = jiffies;
 301         }
 302
 303         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 304                 int ok = misrouted_irq(irq);
 305                 if (action_ret == IRQ_NONE)
 306                         desc->irqs_unhandled -= ok;
 307         }
 308
 309         desc->irq_count++;
 310         if (likely(desc->irq_count < 100000))
 311                 return;
 312
 313         desc->irq_count = 0;
 314         if (unlikely(desc->irqs_unhandled > 99900)) {
 315                 /*
 316                  * The interrupt is stuck
 317                  */
 318                 __report_bad_irq(irq, desc, action_ret);
 319                 /*
 320                  * Now kill the IRQ
 321                  */
 322                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 323                 desc->istate |= IRQS_SPURIOUS_DISABLED;
 324                 desc->depth++;
 325                 irq_disable(desc);
 326
 327                 mod_timer(&poll_spurious_irq_timer,
 328                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 329         }
 330         desc->irqs_unhandled = 0;
 331 }
 332
 333 bool noirqdebug __read_mostly;
 334
 335 int noirqdebug_setup(char *str)
 336 {
 337         noirqdebug = 1;
 338         printk(KERN_INFO "IRQ lockup detection disabled\n");
 339
 340         return 1;
 341 }
 342
 343 __setup("noirqdebug", noirqdebug_setup);
 344 module_param(noirqdebug, bool, 0644);
 345 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 346
 347 static int __init irqfixup_setup(char *str)
 348 {
 349         irqfixup = 1;
 350         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 351         printk(KERN_WARNING "This may impact system performance.\n");
 352
 353         return 1;
 354 }
 355
 356 __setup("irqfixup", irqfixup_setup);
 357 module_param(irqfixup, int, 0644);
 358
 359 static int __init irqpoll_setup(char *str)
 360 {
 361         irqfixup = 2;
 362         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 363                                 "enabled\n");
 364         printk(KERN_WARNING "This may significantly impact system "
 365                                 "performance\n");
 366         return 1;
 367 }
 368
 369 __setup("irqpoll", irqpoll_setup);