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   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 static int irqfixup __read_mostly;
  18
  19 #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10)
  20 static void poll_spurious_irqs(unsigned long dummy);
  21 static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0);
  22
  23 /*
  24  * Recovery handler for misrouted interrupts.
  25  */
  26 static int try_one_irq(int irq, struct irq_desc *desc)
  27 {
  28         struct irqaction *action;
  29         int ok = 0, work = 0;
  30
  31         spin_lock(&desc->lock);
  32         /* Already running on another processor */
  33         if (desc->status & IRQ_INPROGRESS) {
  34                 /*
  35                  * Already running: If it is shared get the other
  36                  * CPU to go looking for our mystery interrupt too
  37                  */
  38                 if (desc->action && (desc->action->flags & IRQF_SHARED))
  39                         desc->status |= IRQ_PENDING;
  40                 spin_unlock(&desc->lock);
  41                 return ok;
  42         }
  43         /* Honour the normal IRQ locking */
  44         desc->status |= IRQ_INPROGRESS;
  45         action = desc->action;
  46         spin_unlock(&desc->lock);
  47
  48         while (action) {
  49                 /* Only shared IRQ handlers are safe to call */
  50                 if (action->flags & IRQF_SHARED) {
  51                         if (action->handler(irq, action->dev_id) ==
  52                                 IRQ_HANDLED)
  53                                 ok = 1;
  54                 }
  55                 action = action->next;
  56         }
  57         local_irq_disable();
  58         /* Now clean up the flags */
  59         spin_lock(&desc->lock);
  60         action = desc->action;
  61
  62         /*
  63          * While we were looking for a fixup someone queued a real
  64          * IRQ clashing with our walk:
  65          */
  66         while ((desc->status & IRQ_PENDING) && action) {
  67                 /*
  68                  * Perform real IRQ processing for the IRQ we deferred
  69                  */
  70                 work = 1;
  71                 spin_unlock(&desc->lock);
  72                 handle_IRQ_event(irq, action);
  73                 spin_lock(&desc->lock);
  74                 desc->status &= ~IRQ_PENDING;
  75         }
  76         desc->status &= ~IRQ_INPROGRESS;
  77         /*
  78          * If we did actual work for the real IRQ line we must let the
  79          * IRQ controller clean up too
  80          */
  81         if (work && desc->chip && desc->chip->end)
  82                 desc->chip->end(irq);
  83         spin_unlock(&desc->lock);
  84
  85         return ok;
  86 }
  87
  88 static int misrouted_irq(int irq)
  89 {
  90         struct irq_desc *desc;
  91         int i, ok = 0;
  92
  93         for_each_irq_desc(i, desc) {
  94                 if (!i)
  95                          continue;
  96
  97                 if (i == irq)   /* Already tried */
  98                         continue;
  99
 100                 if (try_one_irq(i, desc))
 101                         ok = 1;
 102         }
 103         /* So the caller can adjust the irq error counts */
 104         return ok;
 105 }
 106
 107 static void poll_all_shared_irqs(void)
 108 {
 109         struct irq_desc *desc;
 110         int i;
 111
 112         for_each_irq_desc(i, desc) {
 113                 unsigned int status;
 114
 115                 if (!i)
 116                          continue;
 117
 118                 /* Racy but it doesn't matter */
 119                 status = desc->status;
 120                 barrier();
 121                 if (!(status & IRQ_SPURIOUS_DISABLED))
 122                         continue;
 123
 124                 local_irq_disable();
 125                 try_one_irq(i, desc);
 126                 local_irq_enable();
 127         }
 128 }
 129
 130 static void poll_spurious_irqs(unsigned long dummy)
 131 {
 132         poll_all_shared_irqs();
 133
 134         mod_timer(&poll_spurious_irq_timer,
 135                   jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 136 }
 137
 138 #ifdef CONFIG_DEBUG_SHIRQ
 139 void debug_poll_all_shared_irqs(void)
 140 {
 141         poll_all_shared_irqs();
 142 }
 143 #endif
 144
 145 /*
 146  * If 99,900 of the previous 100,000 interrupts have not been handled
 147  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 148  * and try to turn the IRQ off.
 149  *
 150  * (The other 100-of-100,000 interrupts may have been a correctly
 151  *  functioning device sharing an IRQ with the failing one)
 152  *
 153  * Called under desc->lock
 154  */
 155
 156 static void
 157 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 158                  irqreturn_t action_ret)
 159 {
 160         struct irqaction *action;
 161
 162         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 163                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 164                                 irq, action_ret);
 165         } else {
 166                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 167                                 "the \"irqpoll\" option)\n", irq);
 168         }
 169         dump_stack();
 170         printk(KERN_ERR "handlers:\n");
 171
 172         action = desc->action;
 173         while (action) {
 174                 printk(KERN_ERR "[<%p>]", action->handler);
 175                 print_symbol(" (%s)",
 176                         (unsigned long)action->handler);
 177                 printk("\n");
 178                 action = action->next;
 179         }
 180 }
 181
 182 static void
 183 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 184 {
 185         static int count = 100;
 186
 187         if (count > 0) {
 188                 count--;
 189                 __report_bad_irq(irq, desc, action_ret);
 190         }
 191 }
 192
 193 static inline int
 194 try_misrouted_irq(unsigned int irq, struct irq_desc *desc,
 195                   irqreturn_t action_ret)
 196 {
 197         struct irqaction *action;
 198
 199         if (!irqfixup)
 200                 return 0;
 201
 202         /* We didn't actually handle the IRQ - see if it was misrouted? */
 203         if (action_ret == IRQ_NONE)
 204                 return 1;
 205
 206         /*
 207          * But for 'irqfixup == 2' we also do it for handled interrupts if
 208          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 209          * traditional PC timer interrupt.. Legacy)
 210          */
 211         if (irqfixup < 2)
 212                 return 0;
 213
 214         if (!irq)
 215                 return 1;
 216
 217         /*
 218          * Since we don't get the descriptor lock, "action" can
 219          * change under us.  We don't really care, but we don't
 220          * want to follow a NULL pointer. So tell the compiler to
 221          * just load it once by using a barrier.
 222          */
 223         action = desc->action;
 224         barrier();
 225         return action && (action->flags & IRQF_IRQPOLL);
 226 }
 227
 228 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 229                     irqreturn_t action_ret)
 230 {
 231         if (unlikely(action_ret != IRQ_HANDLED)) {
 232                 /*
 233                  * If we are seeing only the odd spurious IRQ caused by
 234                  * bus asynchronicity then don't eventually trigger an error,
 235                  * otherwise the couter becomes a doomsday timer for otherwise
 236                  * working systems
 237                  */
 238                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 239                         desc->irqs_unhandled = 1;
 240                 else
 241                         desc->irqs_unhandled++;
 242                 desc->last_unhandled = jiffies;
 243                 if (unlikely(action_ret != IRQ_NONE))
 244                         report_bad_irq(irq, desc, action_ret);
 245         }
 246
 247         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 248                 int ok = misrouted_irq(irq);
 249                 if (action_ret == IRQ_NONE)
 250                         desc->irqs_unhandled -= ok;
 251         }
 252
 253         desc->irq_count++;
 254         if (likely(desc->irq_count < 100000))
 255                 return;
 256
 257         desc->irq_count = 0;
 258         if (unlikely(desc->irqs_unhandled > 99900)) {
 259                 /*
 260                  * The interrupt is stuck
 261                  */
 262                 __report_bad_irq(irq, desc, action_ret);
 263                 /*
 264                  * Now kill the IRQ
 265                  */
 266                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 267                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
 268                 desc->depth++;
 269                 desc->chip->disable(irq);
 270
 271                 mod_timer(&poll_spurious_irq_timer,
 272                           jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 273         }
 274         desc->irqs_unhandled = 0;
 275 }
 276
 277 int noirqdebug __read_mostly;
 278
 279 int noirqdebug_setup(char *str)
 280 {
 281         noirqdebug = 1;
 282         printk(KERN_INFO "IRQ lockup detection disabled\n");
 283
 284         return 1;
 285 }
 286
 287 __setup("noirqdebug", noirqdebug_setup);
 288 module_param(noirqdebug, bool, 0644);
 289 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 290
 291 static int __init irqfixup_setup(char *str)
 292 {
 293         irqfixup = 1;
 294         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 295         printk(KERN_WARNING "This may impact system performance.\n");
 296
 297         return 1;
 298 }
 299
 300 __setup("irqfixup", irqfixup_setup);
 301 module_param(irqfixup, int, 0644);
 302
 303 static int __init irqpoll_setup(char *str)
 304 {
 305         irqfixup = 2;
 306         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 307                                 "enabled\n");
 308         printk(KERN_WARNING "This may significantly impact system "
 309                                 "performance\n");
 310         return 1;
 311 }
 312
 313 __setup("irqpoll", irqpoll_setup);