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   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/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/random.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/kernel_stat.h>
  19 #include <linux/rculist.h>
  20 #include <linux/hash.h>
  21 #include <linux/bootmem.h>
  22 #include <trace/events/irq.h>
  23
  24 #include "internals.h"
  25
  26 /*
  27  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  28  */
  29 struct lock_class_key irq_desc_lock_class;
  30
  31 /**
  32  * handle_bad_irq - handle spurious and unhandled irqs
  33  * @irq:       the interrupt number
  34  * @desc:      description of the interrupt
  35  *
  36  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  37  */
  38 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  39 {
  40         print_irq_desc(irq, desc);
  41         kstat_incr_irqs_this_cpu(irq, desc);
  42         ack_bad_irq(irq);
  43 }
  44
  45 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
  46 static void __init init_irq_default_affinity(void)
  47 {
  48         alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
  49         cpumask_setall(irq_default_affinity);
  50 }
  51 #else
  52 static void __init init_irq_default_affinity(void)
  53 {
  54 }
  55 #endif
  56
  57 /*
  58  * Linux has a controller-independent interrupt architecture.
  59  * Every controller has a 'controller-template', that is used
  60  * by the main code to do the right thing. Each driver-visible
  61  * interrupt source is transparently wired to the appropriate
  62  * controller. Thus drivers need not be aware of the
  63  * interrupt-controller.
  64  *
  65  * The code is designed to be easily extended with new/different
  66  * interrupt controllers, without having to do assembly magic or
  67  * having to touch the generic code.
  68  *
  69  * Controller mappings for all interrupt sources:
  70  */
  71 int nr_irqs = NR_IRQS;
  72 EXPORT_SYMBOL_GPL(nr_irqs);
  73
  74 #ifdef CONFIG_SPARSE_IRQ
  75
  76 static struct irq_desc irq_desc_init = {
  77         .irq        = -1,
  78         .status     = IRQ_DISABLED,
  79         .chip       = &no_irq_chip,
  80         .handle_irq = handle_bad_irq,
  81         .depth      = 1,
  82         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  83 };
  84
  85 void __ref init_kstat_irqs(struct irq_desc *desc, int node, int nr)
  86 {
  87         void *ptr;
  88
  89         if (slab_is_available())
  90                 ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
  91                                    GFP_ATOMIC, node);
  92         else
  93                 ptr = alloc_bootmem_node(NODE_DATA(node),
  94                                 nr * sizeof(*desc->kstat_irqs));
  95
  96         /*
  97          * don't overwite if can not get new one
  98          * init_copy_kstat_irqs() could still use old one
  99          */
 100         if (ptr) {
 101                 printk(KERN_DEBUG "  alloc kstat_irqs on node %d\n", node);
 102                 desc->kstat_irqs = ptr;
 103         }
 104 }
 105
 106 static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
 107 {
 108         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 109
 110         spin_lock_init(&desc->lock);
 111         desc->irq = irq;
 112 #ifdef CONFIG_SMP
 113         desc->node = node;
 114 #endif
 115         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 116         init_kstat_irqs(desc, node, nr_cpu_ids);
 117         if (!desc->kstat_irqs) {
 118                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 119                 BUG_ON(1);
 120         }
 121         if (!alloc_desc_masks(desc, node, false)) {
 122                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 123                 BUG_ON(1);
 124         }
 125         init_desc_masks(desc);
 126         arch_init_chip_data(desc, node);
 127 }
 128
 129 /*
 130  * Protect the sparse_irqs:
 131  */
 132 DEFINE_SPINLOCK(sparse_irq_lock);
 133
 134 struct irq_desc **irq_desc_ptrs __read_mostly;
 135
 136 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 137         [0 ... NR_IRQS_LEGACY-1] = {
 138                 .irq        = -1,
 139                 .status     = IRQ_DISABLED,
 140                 .chip       = &no_irq_chip,
 141                 .handle_irq = handle_bad_irq,
 142                 .depth      = 1,
 143                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 144         }
 145 };
 146
 147 static unsigned int *kstat_irqs_legacy;
 148
 149 int __init early_irq_init(void)
 150 {
 151         struct irq_desc *desc;
 152         int legacy_count;
 153         int node;
 154         int i;
 155
 156         init_irq_default_affinity();
 157
 158          /* initialize nr_irqs based on nr_cpu_ids */
 159         arch_probe_nr_irqs();
 160         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 161
 162         desc = irq_desc_legacy;
 163         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 164         node = first_online_node;
 165
 166         /* allocate irq_desc_ptrs array based on nr_irqs */
 167         irq_desc_ptrs = kcalloc(nr_irqs, sizeof(void *), GFP_NOWAIT);
 168
 169         /* allocate based on nr_cpu_ids */
 170         kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
 171                                           sizeof(int), GFP_NOWAIT, node);
 172
 173         for (i = 0; i < legacy_count; i++) {
 174                 desc[i].irq = i;
 175 #ifdef CONFIG_SMP
 176                 desc[i].node = node;
 177 #endif
 178                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 179                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 180                 alloc_desc_masks(&desc[i], node, true);
 181                 init_desc_masks(&desc[i]);
 182                 irq_desc_ptrs[i] = desc + i;
 183         }
 184
 185         for (i = legacy_count; i < nr_irqs; i++)
 186                 irq_desc_ptrs[i] = NULL;
 187
 188         return arch_early_irq_init();
 189 }
 190
 191 struct irq_desc *irq_to_desc(unsigned int irq)
 192 {
 193         if (irq_desc_ptrs && irq < nr_irqs)
 194                 return irq_desc_ptrs[irq];
 195
 196         return NULL;
 197 }
 198
 199 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 200 {
 201         struct irq_desc *desc;
 202         unsigned long flags;
 203
 204         if (irq >= nr_irqs) {
 205                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 206                         irq, nr_irqs);
 207                 return NULL;
 208         }
 209
 210         desc = irq_desc_ptrs[irq];
 211         if (desc)
 212                 return desc;
 213
 214         spin_lock_irqsave(&sparse_irq_lock, flags);
 215
 216         /* We have to check it to avoid races with another CPU */
 217         desc = irq_desc_ptrs[irq];
 218         if (desc)
 219                 goto out_unlock;
 220
 221         if (slab_is_available())
 222                 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 223         else
 224                 desc = alloc_bootmem_node(NODE_DATA(node), sizeof(*desc));
 225
 226         printk(KERN_DEBUG "  alloc irq_desc for %d on node %d\n", irq, node);
 227         if (!desc) {
 228                 printk(KERN_ERR "can not alloc irq_desc\n");
 229                 BUG_ON(1);
 230         }
 231         init_one_irq_desc(irq, desc, node);
 232
 233         irq_desc_ptrs[irq] = desc;
 234
 235 out_unlock:
 236         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 237
 238         return desc;
 239 }
 240
 241 #else /* !CONFIG_SPARSE_IRQ */
 242
 243 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 244         [0 ... NR_IRQS-1] = {
 245                 .status = IRQ_DISABLED,
 246                 .chip = &no_irq_chip,
 247                 .handle_irq = handle_bad_irq,
 248                 .depth = 1,
 249                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 250         }
 251 };
 252
 253 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 254 int __init early_irq_init(void)
 255 {
 256         struct irq_desc *desc;
 257         int count;
 258         int i;
 259
 260         init_irq_default_affinity();
 261
 262         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 263
 264         desc = irq_desc;
 265         count = ARRAY_SIZE(irq_desc);
 266
 267         for (i = 0; i < count; i++) {
 268                 desc[i].irq = i;
 269                 alloc_desc_masks(&desc[i], 0, true);
 270                 init_desc_masks(&desc[i]);
 271                 desc[i].kstat_irqs = kstat_irqs_all[i];
 272         }
 273         return arch_early_irq_init();
 274 }
 275
 276 struct irq_desc *irq_to_desc(unsigned int irq)
 277 {
 278         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 279 }
 280
 281 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 282 {
 283         return irq_to_desc(irq);
 284 }
 285 #endif /* !CONFIG_SPARSE_IRQ */
 286
 287 void clear_kstat_irqs(struct irq_desc *desc)
 288 {
 289         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 290 }
 291
 292 /*
 293  * What should we do if we get a hw irq event on an illegal vector?
 294  * Each architecture has to answer this themself.
 295  */
 296 static void ack_bad(unsigned int irq)
 297 {
 298         struct irq_desc *desc = irq_to_desc(irq);
 299
 300         print_irq_desc(irq, desc);
 301         ack_bad_irq(irq);
 302 }
 303
 304 /*
 305  * NOP functions
 306  */
 307 static void noop(unsigned int irq)
 308 {
 309 }
 310
 311 static unsigned int noop_ret(unsigned int irq)
 312 {
 313         return 0;
 314 }
 315
 316 /*
 317  * Generic no controller implementation
 318  */
 319 struct irq_chip no_irq_chip = {
 320         .name           = "none",
 321         .startup        = noop_ret,
 322         .shutdown       = noop,
 323         .enable         = noop,
 324         .disable        = noop,
 325         .ack            = ack_bad,
 326         .end            = noop,
 327 };
 328
 329 /*
 330  * Generic dummy implementation which can be used for
 331  * real dumb interrupt sources
 332  */
 333 struct irq_chip dummy_irq_chip = {
 334         .name           = "dummy",
 335         .startup        = noop_ret,
 336         .shutdown       = noop,
 337         .enable         = noop,
 338         .disable        = noop,
 339         .ack            = noop,
 340         .mask           = noop,
 341         .unmask         = noop,
 342         .end            = noop,
 343 };
 344
 345 /*
 346  * Special, empty irq handler:
 347  */
 348 irqreturn_t no_action(int cpl, void *dev_id)
 349 {
 350         return IRQ_NONE;
 351 }
 352
 353 static void warn_no_thread(unsigned int irq, struct irqaction *action)
 354 {
 355         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
 356                 return;
 357
 358         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
 359                "but no thread function available.", irq, action->name);
 360 }
 361
 362 /**
 363  * handle_IRQ_event - irq action chain handler
 364  * @irq:        the interrupt number
 365  * @action:     the interrupt action chain for this irq
 366  *
 367  * Handles the action chain of an irq event
 368  */
 369 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 370 {
 371         irqreturn_t ret, retval = IRQ_NONE;
 372         unsigned int status = 0;
 373
 374         if (!(action->flags & IRQF_DISABLED))
 375                 local_irq_enable_in_hardirq();
 376
 377         do {
 378                 trace_irq_handler_entry(irq, action);
 379                 ret = action->handler(irq, action->dev_id);
 380                 trace_irq_handler_exit(irq, action, ret);
 381
 382                 switch (ret) {
 383                 case IRQ_WAKE_THREAD:
 384                         /*
 385                          * Set result to handled so the spurious check
 386                          * does not trigger.
 387                          */
 388                         ret = IRQ_HANDLED;
 389
 390                         /*
 391                          * Catch drivers which return WAKE_THREAD but
 392                          * did not set up a thread function
 393                          */
 394                         if (unlikely(!action->thread_fn)) {
 395                                 warn_no_thread(irq, action);
 396                                 break;
 397                         }
 398
 399                         /*
 400                          * Wake up the handler thread for this
 401                          * action. In case the thread crashed and was
 402                          * killed we just pretend that we handled the
 403                          * interrupt. The hardirq handler above has
 404                          * disabled the device interrupt, so no irq
 405                          * storm is lurking.
 406                          */
 407                         if (likely(!test_bit(IRQTF_DIED,
 408                                              &action->thread_flags))) {
 409                                 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
 410                                 wake_up_process(action->thread);
 411                         }
 412
 413                         /* Fall through to add to randomness */
 414                 case IRQ_HANDLED:
 415                         status |= action->flags;
 416                         break;
 417
 418                 default:
 419                         break;
 420                 }
 421
 422                 retval |= ret;
 423                 action = action->next;
 424         } while (action);
 425
 426         if (status & IRQF_SAMPLE_RANDOM)
 427                 add_interrupt_randomness(irq);
 428         local_irq_disable();
 429
 430         return retval;
 431 }
 432
 433 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 434
 435 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
 436 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
 437 #endif
 438
 439 /**
 440  * __do_IRQ - original all in one highlevel IRQ handler
 441  * @irq:        the interrupt number
 442  *
 443  * __do_IRQ handles all normal device IRQ's (the special
 444  * SMP cross-CPU interrupts have their own specific
 445  * handlers).
 446  *
 447  * This is the original x86 implementation which is used for every
 448  * interrupt type.
 449  */
 450 unsigned int __do_IRQ(unsigned int irq)
 451 {
 452         struct irq_desc *desc = irq_to_desc(irq);
 453         struct irqaction *action;
 454         unsigned int status;
 455
 456         kstat_incr_irqs_this_cpu(irq, desc);
 457
 458         if (CHECK_IRQ_PER_CPU(desc->status)) {
 459                 irqreturn_t action_ret;
 460
 461                 /*
 462                  * No locking required for CPU-local interrupts:
 463                  */
 464                 if (desc->chip->ack)
 465                         desc->chip->ack(irq);
 466                 if (likely(!(desc->status & IRQ_DISABLED))) {
 467                         action_ret = handle_IRQ_event(irq, desc->action);
 468                         if (!noirqdebug)
 469                                 note_interrupt(irq, desc, action_ret);
 470                 }
 471                 desc->chip->end(irq);
 472                 return 1;
 473         }
 474
 475         spin_lock(&desc->lock);
 476         if (desc->chip->ack)
 477                 desc->chip->ack(irq);
 478         /*
 479          * REPLAY is when Linux resends an IRQ that was dropped earlier
 480          * WAITING is used by probe to mark irqs that are being tested
 481          */
 482         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 483         status |= IRQ_PENDING; /* we _want_ to handle it */
 484
 485         /*
 486          * If the IRQ is disabled for whatever reason, we cannot
 487          * use the action we have.
 488          */
 489         action = NULL;
 490         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 491                 action = desc->action;
 492                 status &= ~IRQ_PENDING; /* we commit to handling */
 493                 status |= IRQ_INPROGRESS; /* we are handling it */
 494         }
 495         desc->status = status;
 496
 497         /*
 498          * If there is no IRQ handler or it was disabled, exit early.
 499          * Since we set PENDING, if another processor is handling
 500          * a different instance of this same irq, the other processor
 501          * will take care of it.
 502          */
 503         if (unlikely(!action))
 504                 goto out;
 505
 506         /*
 507          * Edge triggered interrupts need to remember
 508          * pending events.
 509          * This applies to any hw interrupts that allow a second
 510          * instance of the same irq to arrive while we are in do_IRQ
 511          * or in the handler. But the code here only handles the _second_
 512          * instance of the irq, not the third or fourth. So it is mostly
 513          * useful for irq hardware that does not mask cleanly in an
 514          * SMP environment.
 515          */
 516         for (;;) {
 517                 irqreturn_t action_ret;
 518
 519                 spin_unlock(&desc->lock);
 520
 521                 action_ret = handle_IRQ_event(irq, action);
 522                 if (!noirqdebug)
 523                         note_interrupt(irq, desc, action_ret);
 524
 525                 spin_lock(&desc->lock);
 526                 if (likely(!(desc->status & IRQ_PENDING)))
 527                         break;
 528                 desc->status &= ~IRQ_PENDING;
 529         }
 530         desc->status &= ~IRQ_INPROGRESS;
 531
 532 out:
 533         /*
 534          * The ->end() handler has to deal with interrupts which got
 535          * disabled while the handler was running.
 536          */
 537         desc->chip->end(irq);
 538         spin_unlock(&desc->lock);
 539
 540         return 1;
 541 }
 542 #endif
 543
 544 void early_init_irq_lock_class(void)
 545 {
 546         struct irq_desc *desc;
 547         int i;
 548
 549         for_each_irq_desc(i, desc) {
 550                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 551         }
 552 }
 553
 554 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 555 {
 556         struct irq_desc *desc = irq_to_desc(irq);
 557         return desc ? desc->kstat_irqs[cpu] : 0;
 558 }
 559 EXPORT_SYMBOL(kstat_irqs_cpu);
 560