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