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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_bootmem_cpumask_var(&irq_default_affinity);
  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                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 176                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 177                 alloc_desc_masks(&desc[i], node, true);
 178                 init_desc_masks(&desc[i]);
 179                 irq_desc_ptrs[i] = desc + i;
 180         }
 181
 182         for (i = legacy_count; i < nr_irqs; i++)
 183                 irq_desc_ptrs[i] = NULL;
 184
 185         return arch_early_irq_init();
 186 }
 187
 188 struct irq_desc *irq_to_desc(unsigned int irq)
 189 {
 190         if (irq_desc_ptrs && irq < nr_irqs)
 191                 return irq_desc_ptrs[irq];
 192
 193         return NULL;
 194 }
 195
 196 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 197 {
 198         struct irq_desc *desc;
 199         unsigned long flags;
 200
 201         if (irq >= nr_irqs) {
 202                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 203                         irq, nr_irqs);
 204                 return NULL;
 205         }
 206
 207         desc = irq_desc_ptrs[irq];
 208         if (desc)
 209                 return desc;
 210
 211         spin_lock_irqsave(&sparse_irq_lock, flags);
 212
 213         /* We have to check it to avoid races with another CPU */
 214         desc = irq_desc_ptrs[irq];
 215         if (desc)
 216                 goto out_unlock;
 217
 218         if (slab_is_available())
 219                 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 220         else
 221                 desc = alloc_bootmem_node(NODE_DATA(node), sizeof(*desc));
 222
 223         printk(KERN_DEBUG "  alloc irq_desc for %d on node %d\n", irq, node);
 224         if (!desc) {
 225                 printk(KERN_ERR "can not alloc irq_desc\n");
 226                 BUG_ON(1);
 227         }
 228         init_one_irq_desc(irq, desc, node);
 229
 230         irq_desc_ptrs[irq] = desc;
 231
 232 out_unlock:
 233         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 234
 235         return desc;
 236 }
 237
 238 #else /* !CONFIG_SPARSE_IRQ */
 239
 240 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 241         [0 ... NR_IRQS-1] = {
 242                 .status = IRQ_DISABLED,
 243                 .chip = &no_irq_chip,
 244                 .handle_irq = handle_bad_irq,
 245                 .depth = 1,
 246                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 247         }
 248 };
 249
 250 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 251 int __init early_irq_init(void)
 252 {
 253         struct irq_desc *desc;
 254         int count;
 255         int i;
 256
 257         init_irq_default_affinity();
 258
 259         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 260
 261         desc = irq_desc;
 262         count = ARRAY_SIZE(irq_desc);
 263
 264         for (i = 0; i < count; i++) {
 265                 desc[i].irq = i;
 266                 alloc_desc_masks(&desc[i], 0, true);
 267                 init_desc_masks(&desc[i]);
 268                 desc[i].kstat_irqs = kstat_irqs_all[i];
 269         }
 270         return arch_early_irq_init();
 271 }
 272
 273 struct irq_desc *irq_to_desc(unsigned int irq)
 274 {
 275         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 276 }
 277
 278 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 279 {
 280         return irq_to_desc(irq);
 281 }
 282 #endif /* !CONFIG_SPARSE_IRQ */
 283
 284 void clear_kstat_irqs(struct irq_desc *desc)
 285 {
 286         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 287 }
 288
 289 /*
 290  * What should we do if we get a hw irq event on an illegal vector?
 291  * Each architecture has to answer this themself.
 292  */
 293 static void ack_bad(unsigned int irq)
 294 {
 295         struct irq_desc *desc = irq_to_desc(irq);
 296
 297         print_irq_desc(irq, desc);
 298         ack_bad_irq(irq);
 299 }
 300
 301 /*
 302  * NOP functions
 303  */
 304 static void noop(unsigned int irq)
 305 {
 306 }
 307
 308 static unsigned int noop_ret(unsigned int irq)
 309 {
 310         return 0;
 311 }
 312
 313 /*
 314  * Generic no controller implementation
 315  */
 316 struct irq_chip no_irq_chip = {
 317         .name           = "none",
 318         .startup        = noop_ret,
 319         .shutdown       = noop,
 320         .enable         = noop,
 321         .disable        = noop,
 322         .ack            = ack_bad,
 323         .end            = noop,
 324 };
 325
 326 /*
 327  * Generic dummy implementation which can be used for
 328  * real dumb interrupt sources
 329  */
 330 struct irq_chip dummy_irq_chip = {
 331         .name           = "dummy",
 332         .startup        = noop_ret,
 333         .shutdown       = noop,
 334         .enable         = noop,
 335         .disable        = noop,
 336         .ack            = noop,
 337         .mask           = noop,
 338         .unmask         = noop,
 339         .end            = noop,
 340 };
 341
 342 /*
 343  * Special, empty irq handler:
 344  */
 345 irqreturn_t no_action(int cpl, void *dev_id)
 346 {
 347         return IRQ_NONE;
 348 }
 349
 350 static void warn_no_thread(unsigned int irq, struct irqaction *action)
 351 {
 352         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
 353                 return;
 354
 355         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
 356                "but no thread function available.", irq, action->name);
 357 }
 358
 359 /**
 360  * handle_IRQ_event - irq action chain handler
 361  * @irq:        the interrupt number
 362  * @action:     the interrupt action chain for this irq
 363  *
 364  * Handles the action chain of an irq event
 365  */
 366 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 367 {
 368         irqreturn_t ret, retval = IRQ_NONE;
 369         unsigned int status = 0;
 370
 371         if (!(action->flags & IRQF_DISABLED))
 372                 local_irq_enable_in_hardirq();
 373
 374         do {
 375                 trace_irq_handler_entry(irq, action);
 376                 ret = action->handler(irq, action->dev_id);
 377                 trace_irq_handler_exit(irq, action, ret);
 378
 379                 switch (ret) {
 380                 case IRQ_WAKE_THREAD:
 381                         /*
 382                          * Set result to handled so the spurious check
 383                          * does not trigger.
 384                          */
 385                         ret = IRQ_HANDLED;
 386
 387                         /*
 388                          * Catch drivers which return WAKE_THREAD but
 389                          * did not set up a thread function
 390                          */
 391                         if (unlikely(!action->thread_fn)) {
 392                                 warn_no_thread(irq, action);
 393                                 break;
 394                         }
 395
 396                         /*
 397                          * Wake up the handler thread for this
 398                          * action. In case the thread crashed and was
 399                          * killed we just pretend that we handled the
 400                          * interrupt. The hardirq handler above has
 401                          * disabled the device interrupt, so no irq
 402                          * storm is lurking.
 403                          */
 404                         if (likely(!test_bit(IRQTF_DIED,
 405                                              &action->thread_flags))) {
 406                                 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
 407                                 wake_up_process(action->thread);
 408                         }
 409
 410                         /* Fall through to add to randomness */
 411                 case IRQ_HANDLED:
 412                         status |= action->flags;
 413                         break;
 414
 415                 default:
 416                         break;
 417                 }
 418
 419                 retval |= ret;
 420                 action = action->next;
 421         } while (action);
 422
 423         if (status & IRQF_SAMPLE_RANDOM)
 424                 add_interrupt_randomness(irq);
 425         local_irq_disable();
 426
 427         return retval;
 428 }
 429
 430 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 431
 432 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
 433 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
 434 #endif
 435
 436 /**
 437  * __do_IRQ - original all in one highlevel IRQ handler
 438  * @irq:        the interrupt number
 439  *
 440  * __do_IRQ handles all normal device IRQ's (the special
 441  * SMP cross-CPU interrupts have their own specific
 442  * handlers).
 443  *
 444  * This is the original x86 implementation which is used for every
 445  * interrupt type.
 446  */
 447 unsigned int __do_IRQ(unsigned int irq)
 448 {
 449         struct irq_desc *desc = irq_to_desc(irq);
 450         struct irqaction *action;
 451         unsigned int status;
 452
 453         kstat_incr_irqs_this_cpu(irq, desc);
 454
 455         if (CHECK_IRQ_PER_CPU(desc->status)) {
 456                 irqreturn_t action_ret;
 457
 458                 /*
 459                  * No locking required for CPU-local interrupts:
 460                  */
 461                 if (desc->chip->ack)
 462                         desc->chip->ack(irq);
 463                 if (likely(!(desc->status & IRQ_DISABLED))) {
 464                         action_ret = handle_IRQ_event(irq, desc->action);
 465                         if (!noirqdebug)
 466                                 note_interrupt(irq, desc, action_ret);
 467                 }
 468                 desc->chip->end(irq);
 469                 return 1;
 470         }
 471
 472         spin_lock(&desc->lock);
 473         if (desc->chip->ack)
 474                 desc->chip->ack(irq);
 475         /*
 476          * REPLAY is when Linux resends an IRQ that was dropped earlier
 477          * WAITING is used by probe to mark irqs that are being tested
 478          */
 479         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 480         status |= IRQ_PENDING; /* we _want_ to handle it */
 481
 482         /*
 483          * If the IRQ is disabled for whatever reason, we cannot
 484          * use the action we have.
 485          */
 486         action = NULL;
 487         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 488                 action = desc->action;
 489                 status &= ~IRQ_PENDING; /* we commit to handling */
 490                 status |= IRQ_INPROGRESS; /* we are handling it */
 491         }
 492         desc->status = status;
 493
 494         /*
 495          * If there is no IRQ handler or it was disabled, exit early.
 496          * Since we set PENDING, if another processor is handling
 497          * a different instance of this same irq, the other processor
 498          * will take care of it.
 499          */
 500         if (unlikely(!action))
 501                 goto out;
 502
 503         /*
 504          * Edge triggered interrupts need to remember
 505          * pending events.
 506          * This applies to any hw interrupts that allow a second
 507          * instance of the same irq to arrive while we are in do_IRQ
 508          * or in the handler. But the code here only handles the _second_
 509          * instance of the irq, not the third or fourth. So it is mostly
 510          * useful for irq hardware that does not mask cleanly in an
 511          * SMP environment.
 512          */
 513         for (;;) {
 514                 irqreturn_t action_ret;
 515
 516                 spin_unlock(&desc->lock);
 517
 518                 action_ret = handle_IRQ_event(irq, action);
 519                 if (!noirqdebug)
 520                         note_interrupt(irq, desc, action_ret);
 521
 522                 spin_lock(&desc->lock);
 523                 if (likely(!(desc->status & IRQ_PENDING)))
 524                         break;
 525                 desc->status &= ~IRQ_PENDING;
 526         }
 527         desc->status &= ~IRQ_INPROGRESS;
 528
 529 out:
 530         /*
 531          * The ->end() handler has to deal with interrupts which got
 532          * disabled while the handler was running.
 533          */
 534         desc->chip->end(irq);
 535         spin_unlock(&desc->lock);
 536
 537         return 1;
 538 }
 539 #endif
 540
 541 void early_init_irq_lock_class(void)
 542 {
 543         struct irq_desc *desc;
 544         int i;
 545
 546         for_each_irq_desc(i, desc) {
 547                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 548         }
 549 }
 550
 551 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 552 {
 553         struct irq_desc *desc = irq_to_desc(irq);
 554         return desc ? desc->kstat_irqs[cpu] : 0;
 555 }
 556 EXPORT_SYMBOL(kstat_irqs_cpu);
 557