SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #include <linux/bootmem.h>
  21
  22 #define CREATE_TRACE_POINTS
  23 #include <trace/irq.h>
  24
  25 #include "internals.h"
  26
  27 /*
  28  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  29  */
  30 struct lock_class_key irq_desc_lock_class;
  31
  32 /**
  33  * handle_bad_irq - handle spurious and unhandled irqs
  34  * @irq:       the interrupt number
  35  * @desc:      description of the interrupt
  36  *
  37  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  38  */
  39 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  40 {
  41         print_irq_desc(irq, desc);
  42         kstat_incr_irqs_this_cpu(irq, desc);
  43         ack_bad_irq(irq);
  44 }
  45
  46 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
  47 static void __init init_irq_default_affinity(void)
  48 {
  49         alloc_bootmem_cpumask_var(&irq_default_affinity);
  50         cpumask_setall(irq_default_affinity);
  51 }
  52 #else
  53 static void __init init_irq_default_affinity(void)
  54 {
  55 }
  56 #endif
  57
  58 /*
  59  * Linux has a controller-independent interrupt architecture.
  60  * Every controller has a 'controller-template', that is used
  61  * by the main code to do the right thing. Each driver-visible
  62  * interrupt source is transparently wired to the appropriate
  63  * controller. Thus drivers need not be aware of the
  64  * interrupt-controller.
  65  *
  66  * The code is designed to be easily extended with new/different
  67  * interrupt controllers, without having to do assembly magic or
  68  * having to touch the generic code.
  69  *
  70  * Controller mappings for all interrupt sources:
  71  */
  72 int nr_irqs = NR_IRQS;
  73 EXPORT_SYMBOL_GPL(nr_irqs);
  74
  75 #ifdef CONFIG_SPARSE_IRQ
  76
  77 static struct irq_desc irq_desc_init = {
  78         .irq        = -1,
  79         .status     = IRQ_DISABLED,
  80         .chip       = &no_irq_chip,
  81         .handle_irq = handle_bad_irq,
  82         .depth      = 1,
  83         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  84 };
  85
  86 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
  87 {
  88         int node;
  89         void *ptr;
  90
  91         node = cpu_to_node(cpu);
  92         ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node);
  93
  94         /*
  95          * don't overwite if can not get new one
  96          * init_copy_kstat_irqs() could still use old one
  97          */
  98         if (ptr) {
  99                 printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n",
 100                          cpu, node);
 101                 desc->kstat_irqs = ptr;
 102         }
 103 }
 104
 105 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
 106 {
 107         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 108
 109         spin_lock_init(&desc->lock);
 110         desc->irq = irq;
 111 #ifdef CONFIG_SMP
 112         desc->cpu = cpu;
 113 #endif
 114         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 115         init_kstat_irqs(desc, cpu, nr_cpu_ids);
 116         if (!desc->kstat_irqs) {
 117                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 118                 BUG_ON(1);
 119         }
 120         if (!init_alloc_desc_masks(desc, cpu, false)) {
 121                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 122                 BUG_ON(1);
 123         }
 124         arch_init_chip_data(desc, cpu);
 125 }
 126
 127 /*
 128  * Protect the sparse_irqs:
 129  */
 130 DEFINE_SPINLOCK(sparse_irq_lock);
 131
 132 struct irq_desc **irq_desc_ptrs __read_mostly;
 133
 134 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 135         [0 ... NR_IRQS_LEGACY-1] = {
 136                 .irq        = -1,
 137                 .status     = IRQ_DISABLED,
 138                 .chip       = &no_irq_chip,
 139                 .handle_irq = handle_bad_irq,
 140                 .depth      = 1,
 141                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 142         }
 143 };
 144
 145 static unsigned int *kstat_irqs_legacy;
 146
 147 int __init early_irq_init(void)
 148 {
 149         struct irq_desc *desc;
 150         int legacy_count;
 151         int i;
 152
 153         init_irq_default_affinity();
 154
 155          /* initialize nr_irqs based on nr_cpu_ids */
 156         arch_probe_nr_irqs();
 157         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 158
 159         desc = irq_desc_legacy;
 160         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 161
 162         /* allocate irq_desc_ptrs array based on nr_irqs */
 163         irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
 164
 165         /* allocate based on nr_cpu_ids */
 166         /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
 167         kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
 168                                           sizeof(int));
 169
 170         for (i = 0; i < legacy_count; i++) {
 171                 desc[i].irq = i;
 172                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 173                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 174                 init_alloc_desc_masks(&desc[i], 0, true);
 175                 irq_desc_ptrs[i] = desc + i;
 176         }
 177
 178         for (i = legacy_count; i < nr_irqs; i++)
 179                 irq_desc_ptrs[i] = NULL;
 180
 181         return arch_early_irq_init();
 182 }
 183
 184 struct irq_desc *irq_to_desc(unsigned int irq)
 185 {
 186         if (irq_desc_ptrs && irq < nr_irqs)
 187                 return irq_desc_ptrs[irq];
 188
 189         return NULL;
 190 }
 191
 192 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 193 {
 194         struct irq_desc *desc;
 195         unsigned long flags;
 196         int node;
 197
 198         if (irq >= nr_irqs) {
 199                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 200                         irq, nr_irqs);
 201                 return NULL;
 202         }
 203
 204         desc = irq_desc_ptrs[irq];
 205         if (desc)
 206                 return desc;
 207
 208         spin_lock_irqsave(&sparse_irq_lock, flags);
 209
 210         /* We have to check it to avoid races with another CPU */
 211         desc = irq_desc_ptrs[irq];
 212         if (desc)
 213                 goto out_unlock;
 214
 215         node = cpu_to_node(cpu);
 216         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 217         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
 218                  irq, cpu, node);
 219         if (!desc) {
 220                 printk(KERN_ERR "can not alloc irq_desc\n");
 221                 BUG_ON(1);
 222         }
 223         init_one_irq_desc(irq, desc, cpu);
 224
 225         irq_desc_ptrs[irq] = desc;
 226
 227 out_unlock:
 228         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 229
 230         return desc;
 231 }
 232
 233 #else /* !CONFIG_SPARSE_IRQ */
 234
 235 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 236         [0 ... NR_IRQS-1] = {
 237                 .status = IRQ_DISABLED,
 238                 .chip = &no_irq_chip,
 239                 .handle_irq = handle_bad_irq,
 240                 .depth = 1,
 241                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 242         }
 243 };
 244
 245 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 246 int __init early_irq_init(void)
 247 {
 248         struct irq_desc *desc;
 249         int count;
 250         int i;
 251
 252         init_irq_default_affinity();
 253
 254         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 255
 256         desc = irq_desc;
 257         count = ARRAY_SIZE(irq_desc);
 258
 259         for (i = 0; i < count; i++) {
 260                 desc[i].irq = i;
 261                 init_alloc_desc_masks(&desc[i], 0, true);
 262                 desc[i].kstat_irqs = kstat_irqs_all[i];
 263         }
 264         return arch_early_irq_init();
 265 }
 266
 267 struct irq_desc *irq_to_desc(unsigned int irq)
 268 {
 269         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 270 }
 271
 272 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 273 {
 274         return irq_to_desc(irq);
 275 }
 276 #endif /* !CONFIG_SPARSE_IRQ */
 277
 278 void clear_kstat_irqs(struct irq_desc *desc)
 279 {
 280         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 281 }
 282
 283 /*
 284  * What should we do if we get a hw irq event on an illegal vector?
 285  * Each architecture has to answer this themself.
 286  */
 287 static void ack_bad(unsigned int irq)
 288 {
 289         struct irq_desc *desc = irq_to_desc(irq);
 290
 291         print_irq_desc(irq, desc);
 292         ack_bad_irq(irq);
 293 }
 294
 295 /*
 296  * NOP functions
 297  */
 298 static void noop(unsigned int irq)
 299 {
 300 }
 301
 302 static unsigned int noop_ret(unsigned int irq)
 303 {
 304         return 0;
 305 }
 306
 307 /*
 308  * Generic no controller implementation
 309  */
 310 struct irq_chip no_irq_chip = {
 311         .name           = "none",
 312         .startup        = noop_ret,
 313         .shutdown       = noop,
 314         .enable         = noop,
 315         .disable        = noop,
 316         .ack            = ack_bad,
 317         .end            = noop,
 318 };
 319
 320 /*
 321  * Generic dummy implementation which can be used for
 322  * real dumb interrupt sources
 323  */
 324 struct irq_chip dummy_irq_chip = {
 325         .name           = "dummy",
 326         .startup        = noop_ret,
 327         .shutdown       = noop,
 328         .enable         = noop,
 329         .disable        = noop,
 330         .ack            = noop,
 331         .mask           = noop,
 332         .unmask         = noop,
 333         .end            = noop,
 334 };
 335
 336 /*
 337  * Special, empty irq handler:
 338  */
 339 irqreturn_t no_action(int cpl, void *dev_id)
 340 {
 341         return IRQ_NONE;
 342 }
 343
 344 static void warn_no_thread(unsigned int irq, struct irqaction *action)
 345 {
 346         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
 347                 return;
 348
 349         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
 350                "but no thread function available.", irq, action->name);
 351 }
 352
 353 /**
 354  * handle_IRQ_event - irq action chain handler
 355  * @irq:        the interrupt number
 356  * @action:     the interrupt action chain for this irq
 357  *
 358  * Handles the action chain of an irq event
 359  */
 360 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 361 {
 362         irqreturn_t ret, retval = IRQ_NONE;
 363         unsigned int status = 0;
 364
 365         WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
 366
 367         if (!(action->flags & IRQF_DISABLED))
 368                 local_irq_enable_in_hardirq();
 369
 370         do {
 371                 trace_irq_handler_entry(irq, action);
 372                 ret = action->handler(irq, action->dev_id);
 373                 trace_irq_handler_exit(irq, action, ret);
 374
 375                 switch (ret) {
 376                 case IRQ_WAKE_THREAD:
 377                         /*
 378                          * Set result to handled so the spurious check
 379                          * does not trigger.
 380                          */
 381                         ret = IRQ_HANDLED;
 382
 383                         /*
 384                          * Catch drivers which return WAKE_THREAD but
 385                          * did not set up a thread function
 386                          */
 387                         if (unlikely(!action->thread_fn)) {
 388                                 warn_no_thread(irq, action);
 389                                 break;
 390                         }
 391
 392                         /*
 393                          * Wake up the handler thread for this
 394                          * action. In case the thread crashed and was
 395                          * killed we just pretend that we handled the
 396                          * interrupt. The hardirq handler above has
 397                          * disabled the device interrupt, so no irq
 398                          * storm is lurking.
 399                          */
 400                         if (likely(!test_bit(IRQTF_DIED,
 401                                              &action->thread_flags))) {
 402                                 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
 403                                 wake_up_process(action->thread);
 404                         }
 405
 406                         /* Fall through to add to randomness */
 407                 case IRQ_HANDLED:
 408                         status |= action->flags;
 409                         break;
 410
 411                 default:
 412                         break;
 413                 }
 414
 415                 retval |= ret;
 416                 action = action->next;
 417         } while (action);
 418
 419         if (status & IRQF_SAMPLE_RANDOM)
 420                 add_interrupt_randomness(irq);
 421         local_irq_disable();
 422
 423         return retval;
 424 }
 425
 426 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 427
 428 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
 429 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
 430 #endif
 431
 432 /**
 433  * __do_IRQ - original all in one highlevel IRQ handler
 434  * @irq:        the interrupt number
 435  *
 436  * __do_IRQ handles all normal device IRQ's (the special
 437  * SMP cross-CPU interrupts have their own specific
 438  * handlers).
 439  *
 440  * This is the original x86 implementation which is used for every
 441  * interrupt type.
 442  */
 443 unsigned int __do_IRQ(unsigned int irq)
 444 {
 445         struct irq_desc *desc = irq_to_desc(irq);
 446         struct irqaction *action;
 447         unsigned int status;
 448
 449         kstat_incr_irqs_this_cpu(irq, desc);
 450
 451         if (CHECK_IRQ_PER_CPU(desc->status)) {
 452                 irqreturn_t action_ret;
 453
 454                 /*
 455                  * No locking required for CPU-local interrupts:
 456                  */
 457                 if (desc->chip->ack) {
 458                         desc->chip->ack(irq);
 459                         /* get new one */
 460                         desc = irq_remap_to_desc(irq, desc);
 461                 }
 462                 if (likely(!(desc->status & IRQ_DISABLED))) {
 463                         action_ret = handle_IRQ_event(irq, desc->action);
 464                         if (!noirqdebug)
 465                                 note_interrupt(irq, desc, action_ret);
 466                 }
 467                 desc->chip->end(irq);
 468                 return 1;
 469         }
 470
 471         spin_lock(&desc->lock);
 472         if (desc->chip->ack) {
 473                 desc->chip->ack(irq);
 474                 desc = irq_remap_to_desc(irq, desc);
 475         }
 476         /*
 477          * REPLAY is when Linux resends an IRQ that was dropped earlier
 478          * WAITING is used by probe to mark irqs that are being tested
 479          */
 480         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 481         status |= IRQ_PENDING; /* we _want_ to handle it */
 482
 483         /*
 484          * If the IRQ is disabled for whatever reason, we cannot
 485          * use the action we have.
 486          */
 487         action = NULL;
 488         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 489                 action = desc->action;
 490                 status &= ~IRQ_PENDING; /* we commit to handling */
 491                 status |= IRQ_INPROGRESS; /* we are handling it */
 492         }
 493         desc->status = status;
 494
 495         /*
 496          * If there is no IRQ handler or it was disabled, exit early.
 497          * Since we set PENDING, if another processor is handling
 498          * a different instance of this same irq, the other processor
 499          * will take care of it.
 500          */
 501         if (unlikely(!action))
 502                 goto out;
 503
 504         /*
 505          * Edge triggered interrupts need to remember
 506          * pending events.
 507          * This applies to any hw interrupts that allow a second
 508          * instance of the same irq to arrive while we are in do_IRQ
 509          * or in the handler. But the code here only handles the _second_
 510          * instance of the irq, not the third or fourth. So it is mostly
 511          * useful for irq hardware that does not mask cleanly in an
 512          * SMP environment.
 513          */
 514         for (;;) {
 515                 irqreturn_t action_ret;
 516
 517                 spin_unlock(&desc->lock);
 518
 519                 action_ret = handle_IRQ_event(irq, action);
 520                 if (!noirqdebug)
 521                         note_interrupt(irq, desc, action_ret);
 522
 523                 spin_lock(&desc->lock);
 524                 if (likely(!(desc->status & IRQ_PENDING)))
 525                         break;
 526                 desc->status &= ~IRQ_PENDING;
 527         }
 528         desc->status &= ~IRQ_INPROGRESS;
 529
 530 out:
 531         /*
 532          * The ->end() handler has to deal with interrupts which got
 533          * disabled while the handler was running.
 534          */
 535         desc->chip->end(irq);
 536         spin_unlock(&desc->lock);
 537
 538         return 1;
 539 }
 540 #endif
 541
 542 void early_init_irq_lock_class(void)
 543 {
 544         struct irq_desc *desc;
 545         int i;
 546
 547         for_each_irq_desc(i, desc) {
 548                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 549         }
 550 }
 551
 552 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 553 {
 554         struct irq_desc *desc = irq_to_desc(irq);
 555         return desc ? desc->kstat_irqs[cpu] : 0;
 556 }
 557 EXPORT_SYMBOL(kstat_irqs_cpu);
 558