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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;
  30         int work = 0;   /* Did we do work for a real IRQ */
  31
  32         spin_lock(&desc->lock);
  33         /* Already running on another processor */
  34         if (desc->status & IRQ_INPROGRESS) {
  35                 /*
  36                  * Already running: If it is shared get the other
  37                  * CPU to go looking for our mystery interrupt too
  38                  */
  39                 if (desc->action && (desc->action->flags & IRQF_SHARED))
  40                         desc->status |= IRQ_PENDING;
  41                 spin_unlock(&desc->lock);
  42                 return ok;
  43         }
  44         /* Honour the normal IRQ locking */
  45         desc->status |= IRQ_INPROGRESS;
  46         action = desc->action;
  47         spin_unlock(&desc->lock);
  48
  49         while (action) {
  50                 /* Only shared IRQ handlers are safe to call */
  51                 if (action->flags & IRQF_SHARED) {
  52                         if (action->handler(irq, action->dev_id) ==
  53                                 IRQ_HANDLED)
  54                                 ok = 1;
  55                 }
  56                 action = action->next;
  57         }
  58         local_irq_disable();
  59         /* Now clean up the flags */
  60         spin_lock(&desc->lock);
  61         action = desc->action;
  62
  63         /*
  64          * While we were looking for a fixup someone queued a real
  65          * IRQ clashing with our walk:
  66          */
  67         while ((desc->status & IRQ_PENDING) && action) {
  68                 /*
  69                  * Perform real IRQ processing for the IRQ we deferred
  70                  */
  71                 work = 1;
  72                 spin_unlock(&desc->lock);
  73                 handle_IRQ_event(irq, action);
  74                 spin_lock(&desc->lock);
  75                 desc->status &= ~IRQ_PENDING;
  76         }
  77         desc->status &= ~IRQ_INPROGRESS;
  78         /*
  79          * If we did actual work for the real IRQ line we must let the
  80          * IRQ controller clean up too
  81          */
  82         if (work && desc->chip && desc->chip->end)
  83                 desc->chip->end(irq);
  84         spin_unlock(&desc->lock);
  85
  86         return ok;
  87 }
  88
  89 static int misrouted_irq(int irq)
  90 {
  91         int i;
  92         int ok = 0;
  93
  94         for (i = 1; i < nr_irqs; i++) {
  95                 struct irq_desc *desc = irq_desc + i;
  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_spurious_irqs(unsigned long dummy)
 108 {
 109         int i;
 110         for (i = 1; i < nr_irqs; i++) {
 111                 struct irq_desc *desc = irq_desc + i;
 112                 unsigned int status;
 113
 114                 /* Racy but it doesn't matter */
 115                 status = desc->status;
 116                 barrier();
 117                 if (!(status & IRQ_SPURIOUS_DISABLED))
 118                         continue;
 119
 120                 try_one_irq(i, desc);
 121         }
 122
 123         mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 124 }
 125
 126 /*
 127  * If 99,900 of the previous 100,000 interrupts have not been handled
 128  * then assume that the IRQ is stuck in some manner. Drop a diagnostic
 129  * and try to turn the IRQ off.
 130  *
 131  * (The other 100-of-100,000 interrupts may have been a correctly
 132  *  functioning device sharing an IRQ with the failing one)
 133  *
 134  * Called under desc->lock
 135  */
 136
 137 static void
 138 __report_bad_irq(unsigned int irq, struct irq_desc *desc,
 139                  irqreturn_t action_ret)
 140 {
 141         struct irqaction *action;
 142
 143         if (action_ret != IRQ_HANDLED && action_ret != IRQ_NONE) {
 144                 printk(KERN_ERR "irq event %d: bogus return value %x\n",
 145                                 irq, action_ret);
 146         } else {
 147                 printk(KERN_ERR "irq %d: nobody cared (try booting with "
 148                                 "the \"irqpoll\" option)\n", irq);
 149         }
 150         dump_stack();
 151         printk(KERN_ERR "handlers:\n");
 152
 153         action = desc->action;
 154         while (action) {
 155                 printk(KERN_ERR "[<%p>]", action->handler);
 156                 print_symbol(" (%s)",
 157                         (unsigned long)action->handler);
 158                 printk("\n");
 159                 action = action->next;
 160         }
 161 }
 162
 163 static void
 164 report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 165 {
 166         static int count = 100;
 167
 168         if (count > 0) {
 169                 count--;
 170                 __report_bad_irq(irq, desc, action_ret);
 171         }
 172 }
 173
 174 static inline int try_misrouted_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret)
 175 {
 176         struct irqaction *action;
 177
 178         if (!irqfixup)
 179                 return 0;
 180
 181         /* We didn't actually handle the IRQ - see if it was misrouted? */
 182         if (action_ret == IRQ_NONE)
 183                 return 1;
 184
 185         /*
 186          * But for 'irqfixup == 2' we also do it for handled interrupts if
 187          * they are marked as IRQF_IRQPOLL (or for irq zero, which is the
 188          * traditional PC timer interrupt.. Legacy)
 189          */
 190         if (irqfixup < 2)
 191                 return 0;
 192
 193         if (!irq)
 194                 return 1;
 195
 196         /*
 197          * Since we don't get the descriptor lock, "action" can
 198          * change under us.  We don't really care, but we don't
 199          * want to follow a NULL pointer. So tell the compiler to
 200          * just load it once by using a barrier.
 201          */
 202         action = desc->action;
 203         barrier();
 204         return action && (action->flags & IRQF_IRQPOLL);
 205 }
 206
 207 void note_interrupt(unsigned int irq, struct irq_desc *desc,
 208                     irqreturn_t action_ret)
 209 {
 210         if (unlikely(action_ret != IRQ_HANDLED)) {
 211                 /*
 212                  * If we are seeing only the odd spurious IRQ caused by
 213                  * bus asynchronicity then don't eventually trigger an error,
 214                  * otherwise the couter becomes a doomsday timer for otherwise
 215                  * working systems
 216                  */
 217                 if (time_after(jiffies, desc->last_unhandled + HZ/10))
 218                         desc->irqs_unhandled = 1;
 219                 else
 220                         desc->irqs_unhandled++;
 221                 desc->last_unhandled = jiffies;
 222                 if (unlikely(action_ret != IRQ_NONE))
 223                         report_bad_irq(irq, desc, action_ret);
 224         }
 225
 226         if (unlikely(try_misrouted_irq(irq, desc, action_ret))) {
 227                 int ok = misrouted_irq(irq);
 228                 if (action_ret == IRQ_NONE)
 229                         desc->irqs_unhandled -= ok;
 230         }
 231
 232         desc->irq_count++;
 233         if (likely(desc->irq_count < 100000))
 234                 return;
 235
 236         desc->irq_count = 0;
 237         if (unlikely(desc->irqs_unhandled > 99900)) {
 238                 /*
 239                  * The interrupt is stuck
 240                  */
 241                 __report_bad_irq(irq, desc, action_ret);
 242                 /*
 243                  * Now kill the IRQ
 244                  */
 245                 printk(KERN_EMERG "Disabling IRQ #%d\n", irq);
 246                 desc->status |= IRQ_DISABLED | IRQ_SPURIOUS_DISABLED;
 247                 desc->depth++;
 248                 desc->chip->disable(irq);
 249
 250                 mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL);
 251         }
 252         desc->irqs_unhandled = 0;
 253 }
 254
 255 int noirqdebug __read_mostly;
 256
 257 int noirqdebug_setup(char *str)
 258 {
 259         noirqdebug = 1;
 260         printk(KERN_INFO "IRQ lockup detection disabled\n");
 261
 262         return 1;
 263 }
 264
 265 __setup("noirqdebug", noirqdebug_setup);
 266 module_param(noirqdebug, bool, 0644);
 267 MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true");
 268
 269 static int __init irqfixup_setup(char *str)
 270 {
 271         irqfixup = 1;
 272         printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 273         printk(KERN_WARNING "This may impact system performance.\n");
 274
 275         return 1;
 276 }
 277
 278 __setup("irqfixup", irqfixup_setup);
 279 module_param(irqfixup, int, 0644);
 280 MODULE_PARM_DESC("irqfixup", "0: No fixup, 1: irqfixup mode 2: irqpoll mode");
 281
 282 static int __init irqpoll_setup(char *str)
 283 {
 284         irqfixup = 2;
 285         printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 286                                 "enabled\n");
 287         printk(KERN_WARNING "This may significantly impact system "
 288                                 "performance\n");
 289         return 1;
 290 }
 291
 292 __setup("irqpoll", irqpoll_setup);