kernel/irq/handle.c

   1 /*
   2  * linux/kernel/irq/handle.c
   3  *
   4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5  * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
   6  *
   7  * This file contains the core interrupt handling code.
   8  *
   9  * Detailed information is available in Documentation/DocBook/genericirq
  10  *
  11  */
  12
  13 #include <linux/irq.h>
  14 #include <linux/module.h>
  15 #include <linux/random.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel_stat.h>
  18 #include <linux/rculist.h>
  19 #include <linux/hash.h>
  20
  21 #include "internals.h"
  22
  23 /*
  24  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  25  */
  26 struct lock_class_key irq_desc_lock_class;
  27
  28 /**
  29  * handle_bad_irq - handle spurious and unhandled irqs
  30  * @irq:       the interrupt number
  31  * @desc:      description of the interrupt
  32  *
  33  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  34  */
  35 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  36 {
  37         print_irq_desc(irq, desc);
  38         kstat_incr_irqs_this_cpu(irq, desc);
  39         ack_bad_irq(irq);
  40 }
  41
  42 /*
  43  * Linux has a controller-independent interrupt architecture.
  44  * Every controller has a 'controller-template', that is used
  45  * by the main code to do the right thing. Each driver-visible
  46  * interrupt source is transparently wired to the appropriate
  47  * controller. Thus drivers need not be aware of the
  48  * interrupt-controller.
  49  *
  50  * The code is designed to be easily extended with new/different
  51  * interrupt controllers, without having to do assembly magic or
  52  * having to touch the generic code.
  53  *
  54  * Controller mappings for all interrupt sources:
  55  */
  56 int nr_irqs = NR_IRQS;
  57 EXPORT_SYMBOL_GPL(nr_irqs);
  58
  59 #ifdef CONFIG_SPARSE_IRQ
  60 static struct irq_desc irq_desc_init = {
  61         .irq        = -1,
  62         .status     = IRQ_DISABLED,
  63         .chip       = &no_irq_chip,
  64         .handle_irq = handle_bad_irq,
  65         .depth      = 1,
  66         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  67 };
  68
  69 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
  70 {
  71         unsigned long bytes;
  72         char *ptr;
  73         int node;
  74
  75         /* Compute how many bytes we need per irq and allocate them */
  76         bytes = nr * sizeof(unsigned int);
  77
  78         node = cpu_to_node(cpu);
  79         ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
  80         printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);
  81
  82         if (ptr)
  83                 desc->kstat_irqs = (unsigned int *)ptr;
  84 }
  85
  86 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
  87 {
  88         int node = cpu_to_node(cpu);
  89
  90         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
  91
  92         spin_lock_init(&desc->lock);
  93         desc->irq = irq;
  94 #ifdef CONFIG_SMP
  95         desc->cpu = cpu;
  96 #endif
  97         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  98         init_kstat_irqs(desc, cpu, nr_cpu_ids);
  99         if (!desc->kstat_irqs) {
 100                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 101                 BUG_ON(1);
 102         }
 103         if (!init_alloc_desc_masks(desc, node, false)) {
 104                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 105                 BUG_ON(1);
 106         }
 107         arch_init_chip_data(desc, cpu);
 108 }
 109
 110 /*
 111  * Protect the sparse_irqs:
 112  */
 113 DEFINE_SPINLOCK(sparse_irq_lock);
 114
 115 struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
 116
 117 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 118         [0 ... NR_IRQS_LEGACY-1] = {
 119                 .irq        = -1,
 120                 .status     = IRQ_DISABLED,
 121                 .chip       = &no_irq_chip,
 122                 .handle_irq = handle_bad_irq,
 123                 .depth      = 1,
 124                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 125         }
 126 };
 127
 128 /* FIXME: use bootmem alloc ...*/
 129 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
 130
 131 int __init early_irq_init(void)
 132 {
 133         struct irq_desc *desc;
 134         int legacy_count;
 135         int i;
 136
 137         desc = irq_desc_legacy;
 138         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 139
 140         for (i = 0; i < legacy_count; i++) {
 141                 desc[i].irq = i;
 142                 desc[i].kstat_irqs = kstat_irqs_legacy[i];
 143                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 144                 init_alloc_desc_masks(&desc[i], 0, true);
 145                 irq_desc_ptrs[i] = desc + i;
 146         }
 147
 148         for (i = legacy_count; i < NR_IRQS; i++)
 149                 irq_desc_ptrs[i] = NULL;
 150
 151         return arch_early_irq_init();
 152 }
 153
 154 struct irq_desc *irq_to_desc(unsigned int irq)
 155 {
 156         return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
 157 }
 158
 159 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 160 {
 161         struct irq_desc *desc;
 162         unsigned long flags;
 163         int node;
 164
 165         if (irq >= NR_IRQS) {
 166                 printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
 167                                 irq, NR_IRQS);
 168                 WARN_ON(1);
 169                 return NULL;
 170         }
 171
 172         desc = irq_desc_ptrs[irq];
 173         if (desc)
 174                 return desc;
 175
 176         spin_lock_irqsave(&sparse_irq_lock, flags);
 177
 178         /* We have to check it to avoid races with another CPU */
 179         desc = irq_desc_ptrs[irq];
 180         if (desc)
 181                 goto out_unlock;
 182
 183         node = cpu_to_node(cpu);
 184         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 185         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
 186                  irq, cpu, node);
 187         if (!desc) {
 188                 printk(KERN_ERR "can not alloc irq_desc\n");
 189                 BUG_ON(1);
 190         }
 191         if (!init_alloc_desc_masks(desc, node, false)) {
 192                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 193                 BUG_ON(1);
 194         }
 195         init_one_irq_desc(irq, desc, cpu);
 196
 197         irq_desc_ptrs[irq] = desc;
 198
 199 out_unlock:
 200         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 201
 202         return desc;
 203 }
 204
 205 #else /* !CONFIG_SPARSE_IRQ */
 206
 207 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 208         [0 ... NR_IRQS-1] = {
 209                 .status = IRQ_DISABLED,
 210                 .chip = &no_irq_chip,
 211                 .handle_irq = handle_bad_irq,
 212                 .depth = 1,
 213                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 214         }
 215 };
 216
 217 int __init early_irq_init(void)
 218 {
 219         struct irq_desc *desc;
 220         int count;
 221         int i;
 222
 223         desc = irq_desc;
 224         count = ARRAY_SIZE(irq_desc);
 225
 226         for (i = 0; i < count; i++) {
 227                 desc[i].irq = i;
 228                 init_alloc_desc_masks(&desc[i], 0, true);
 229         }
 230         return arch_early_irq_init();
 231 }
 232
 233 struct irq_desc *irq_to_desc(unsigned int irq)
 234 {
 235         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 236 }
 237
 238 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 239 {
 240         return irq_to_desc(irq);
 241 }
 242 #endif /* !CONFIG_SPARSE_IRQ */
 243
 244 /*
 245  * What should we do if we get a hw irq event on an illegal vector?
 246  * Each architecture has to answer this themself.
 247  */
 248 static void ack_bad(unsigned int irq)
 249 {
 250         struct irq_desc *desc = irq_to_desc(irq);
 251
 252         print_irq_desc(irq, desc);
 253         ack_bad_irq(irq);
 254 }
 255
 256 /*
 257  * NOP functions
 258  */
 259 static void noop(unsigned int irq)
 260 {
 261 }
 262
 263 static unsigned int noop_ret(unsigned int irq)
 264 {
 265         return 0;
 266 }
 267
 268 /*
 269  * Generic no controller implementation
 270  */
 271 struct irq_chip no_irq_chip = {
 272         .name           = "none",
 273         .startup        = noop_ret,
 274         .shutdown       = noop,
 275         .enable         = noop,
 276         .disable        = noop,
 277         .ack            = ack_bad,
 278         .end            = noop,
 279 };
 280
 281 /*
 282  * Generic dummy implementation which can be used for
 283  * real dumb interrupt sources
 284  */
 285 struct irq_chip dummy_irq_chip = {
 286         .name           = "dummy",
 287         .startup        = noop_ret,
 288         .shutdown       = noop,
 289         .enable         = noop,
 290         .disable        = noop,
 291         .ack            = noop,
 292         .mask           = noop,
 293         .unmask         = noop,
 294         .end            = noop,
 295 };
 296
 297 /*
 298  * Special, empty irq handler:
 299  */
 300 irqreturn_t no_action(int cpl, void *dev_id)
 301 {
 302         return IRQ_NONE;
 303 }
 304
 305 /**
 306  * handle_IRQ_event - irq action chain handler
 307  * @irq:        the interrupt number
 308  * @action:     the interrupt action chain for this irq
 309  *
 310  * Handles the action chain of an irq event
 311  */
 312 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 313 {
 314         irqreturn_t ret, retval = IRQ_NONE;
 315         unsigned int status = 0;
 316
 317         if (!(action->flags & IRQF_DISABLED))
 318                 local_irq_enable_in_hardirq();
 319
 320         do {
 321                 ret = action->handler(irq, action->dev_id);
 322                 if (ret == IRQ_HANDLED)
 323                         status |= action->flags;
 324                 retval |= ret;
 325                 action = action->next;
 326         } while (action);
 327
 328         if (status & IRQF_SAMPLE_RANDOM)
 329                 add_interrupt_randomness(irq);
 330         local_irq_disable();
 331
 332         return retval;
 333 }
 334
 335 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 336 /**
 337  * __do_IRQ - original all in one highlevel IRQ handler
 338  * @irq:        the interrupt number
 339  *
 340  * __do_IRQ handles all normal device IRQ's (the special
 341  * SMP cross-CPU interrupts have their own specific
 342  * handlers).
 343  *
 344  * This is the original x86 implementation which is used for every
 345  * interrupt type.
 346  */
 347 unsigned int __do_IRQ(unsigned int irq)
 348 {
 349         struct irq_desc *desc = irq_to_desc(irq);
 350         struct irqaction *action;
 351         unsigned int status;
 352
 353         kstat_incr_irqs_this_cpu(irq, desc);
 354
 355         if (CHECK_IRQ_PER_CPU(desc->status)) {
 356                 irqreturn_t action_ret;
 357
 358                 /*
 359                  * No locking required for CPU-local interrupts:
 360                  */
 361                 if (desc->chip->ack) {
 362                         desc->chip->ack(irq);
 363                         /* get new one */
 364                         desc = irq_remap_to_desc(irq, desc);
 365                 }
 366                 if (likely(!(desc->status & IRQ_DISABLED))) {
 367                         action_ret = handle_IRQ_event(irq, desc->action);
 368                         if (!noirqdebug)
 369                                 note_interrupt(irq, desc, action_ret);
 370                 }
 371                 desc->chip->end(irq);
 372                 return 1;
 373         }
 374
 375         spin_lock(&desc->lock);
 376         if (desc->chip->ack) {
 377                 desc->chip->ack(irq);
 378                 desc = irq_remap_to_desc(irq, desc);
 379         }
 380         /*
 381          * REPLAY is when Linux resends an IRQ that was dropped earlier
 382          * WAITING is used by probe to mark irqs that are being tested
 383          */
 384         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 385         status |= IRQ_PENDING; /* we _want_ to handle it */
 386
 387         /*
 388          * If the IRQ is disabled for whatever reason, we cannot
 389          * use the action we have.
 390          */
 391         action = NULL;
 392         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 393                 action = desc->action;
 394                 status &= ~IRQ_PENDING; /* we commit to handling */
 395                 status |= IRQ_INPROGRESS; /* we are handling it */
 396         }
 397         desc->status = status;
 398
 399         /*
 400          * If there is no IRQ handler or it was disabled, exit early.
 401          * Since we set PENDING, if another processor is handling
 402          * a different instance of this same irq, the other processor
 403          * will take care of it.
 404          */
 405         if (unlikely(!action))
 406                 goto out;
 407
 408         /*
 409          * Edge triggered interrupts need to remember
 410          * pending events.
 411          * This applies to any hw interrupts that allow a second
 412          * instance of the same irq to arrive while we are in do_IRQ
 413          * or in the handler. But the code here only handles the _second_
 414          * instance of the irq, not the third or fourth. So it is mostly
 415          * useful for irq hardware that does not mask cleanly in an
 416          * SMP environment.
 417          */
 418         for (;;) {
 419                 irqreturn_t action_ret;
 420
 421                 spin_unlock(&desc->lock);
 422
 423                 action_ret = handle_IRQ_event(irq, action);
 424                 if (!noirqdebug)
 425                         note_interrupt(irq, desc, action_ret);
 426
 427                 spin_lock(&desc->lock);
 428                 if (likely(!(desc->status & IRQ_PENDING)))
 429                         break;
 430                 desc->status &= ~IRQ_PENDING;
 431         }
 432         desc->status &= ~IRQ_INPROGRESS;
 433
 434 out:
 435         /*
 436          * The ->end() handler has to deal with interrupts which got
 437          * disabled while the handler was running.
 438          */
 439         desc->chip->end(irq);
 440         spin_unlock(&desc->lock);
 441
 442         return 1;
 443 }
 444 #endif
 445
 446 void early_init_irq_lock_class(void)
 447 {
 448         struct irq_desc *desc;
 449         int i;
 450
 451         for_each_irq_desc(i, desc) {
 452                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 453         }
 454 }
 455
 456 #ifdef CONFIG_SPARSE_IRQ
 457 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 458 {
 459         struct irq_desc *desc = irq_to_desc(irq);
 460         return desc ? desc->kstat_irqs[cpu] : 0;
 461 }
 462 #endif
 463 EXPORT_SYMBOL(kstat_irqs_cpu);
 464