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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/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/module.h>
  17 #include <linux/random.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/kernel_stat.h>
  20 #include <linux/rculist.h>
  21 #include <linux/hash.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       = __RAW_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         ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
  90                            GFP_ATOMIC, node);
  91
  92         /*
  93          * don't overwite if can not get new one
  94          * init_copy_kstat_irqs() could still use old one
  95          */
  96         if (ptr) {
  97                 printk(KERN_DEBUG "  alloc kstat_irqs on node %d\n", node);
  98                 desc->kstat_irqs = ptr;
  99         }
 100 }
 101
 102 static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
 103 {
 104         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 105
 106         raw_spin_lock_init(&desc->lock);
 107         desc->irq = irq;
 108 #ifdef CONFIG_SMP
 109         desc->node = node;
 110 #endif
 111         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 112         init_kstat_irqs(desc, node, nr_cpu_ids);
 113         if (!desc->kstat_irqs) {
 114                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 115                 BUG_ON(1);
 116         }
 117         if (!alloc_desc_masks(desc, node, false)) {
 118                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 119                 BUG_ON(1);
 120         }
 121         init_desc_masks(desc);
 122         arch_init_chip_data(desc, node);
 123 }
 124
 125 /*
 126  * Protect the sparse_irqs:
 127  */
 128 DEFINE_RAW_SPINLOCK(sparse_irq_lock);
 129
 130 struct irq_desc **irq_desc_ptrs __read_mostly;
 131
 132 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 133         [0 ... NR_IRQS_LEGACY-1] = {
 134                 .irq        = -1,
 135                 .status     = IRQ_DISABLED,
 136                 .chip       = &no_irq_chip,
 137                 .handle_irq = handle_bad_irq,
 138                 .depth      = 1,
 139                 .lock       = __RAW_SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 140         }
 141 };
 142
 143 static unsigned int *kstat_irqs_legacy;
 144
 145 int __init early_irq_init(void)
 146 {
 147         struct irq_desc *desc;
 148         int legacy_count;
 149         int node;
 150         int i;
 151
 152         init_irq_default_affinity();
 153
 154          /* initialize nr_irqs based on nr_cpu_ids */
 155         arch_probe_nr_irqs();
 156         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 157
 158         desc = irq_desc_legacy;
 159         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 160         node = first_online_node;
 161
 162         /* allocate irq_desc_ptrs array based on nr_irqs */
 163         irq_desc_ptrs = kcalloc(nr_irqs, sizeof(void *), GFP_NOWAIT);
 164
 165         /* allocate based on nr_cpu_ids */
 166         kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
 167                                           sizeof(int), GFP_NOWAIT, node);
 168
 169         for (i = 0; i < legacy_count; i++) {
 170                 desc[i].irq = i;
 171 #ifdef CONFIG_SMP
 172                 desc[i].node = node;
 173 #endif
 174                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 175                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 176                 alloc_desc_masks(&desc[i], node, true);
 177                 init_desc_masks(&desc[i]);
 178                 irq_desc_ptrs[i] = desc + i;
 179         }
 180
 181         for (i = legacy_count; i < nr_irqs; i++)
 182                 irq_desc_ptrs[i] = NULL;
 183
 184         return arch_early_irq_init();
 185 }
 186
 187 struct irq_desc *irq_to_desc(unsigned int irq)
 188 {
 189         if (irq_desc_ptrs && irq < nr_irqs)
 190                 return irq_desc_ptrs[irq];
 191
 192         return NULL;
 193 }
 194
 195 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 196 {
 197         struct irq_desc *desc;
 198         unsigned long flags;
 199
 200         if (irq >= nr_irqs) {
 201                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 202                         irq, nr_irqs);
 203                 return NULL;
 204         }
 205
 206         desc = irq_desc_ptrs[irq];
 207         if (desc)
 208                 return desc;
 209
 210         raw_spin_lock_irqsave(&sparse_irq_lock, flags);
 211
 212         /* We have to check it to avoid races with another CPU */
 213         desc = irq_desc_ptrs[irq];
 214         if (desc)
 215                 goto out_unlock;
 216
 217         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 218
 219         printk(KERN_DEBUG "  alloc irq_desc for %d on node %d\n", irq, node);
 220         if (!desc) {
 221                 printk(KERN_ERR "can not alloc irq_desc\n");
 222                 BUG_ON(1);
 223         }
 224         init_one_irq_desc(irq, desc, node);
 225
 226         irq_desc_ptrs[irq] = desc;
 227
 228 out_unlock:
 229         raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
 230
 231         return desc;
 232 }
 233
 234 #else /* !CONFIG_SPARSE_IRQ */
 235
 236 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 237         [0 ... NR_IRQS-1] = {
 238                 .status = IRQ_DISABLED,
 239                 .chip = &no_irq_chip,
 240                 .handle_irq = handle_bad_irq,
 241                 .depth = 1,
 242                 .lock = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
 243         }
 244 };
 245
 246 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 247 int __init early_irq_init(void)
 248 {
 249         struct irq_desc *desc;
 250         int count;
 251         int i;
 252
 253         init_irq_default_affinity();
 254
 255         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 256
 257         desc = irq_desc;
 258         count = ARRAY_SIZE(irq_desc);
 259
 260         for (i = 0; i < count; i++) {
 261                 desc[i].irq = i;
 262                 alloc_desc_masks(&desc[i], 0, true);
 263                 init_desc_masks(&desc[i]);
 264                 desc[i].kstat_irqs = kstat_irqs_all[i];
 265         }
 266         return arch_early_irq_init();
 267 }
 268
 269 struct irq_desc *irq_to_desc(unsigned int irq)
 270 {
 271         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 272 }
 273
 274 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 275 {
 276         return irq_to_desc(irq);
 277 }
 278 #endif /* !CONFIG_SPARSE_IRQ */
 279
 280 void clear_kstat_irqs(struct irq_desc *desc)
 281 {
 282         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 283 }
 284
 285 /*
 286  * What should we do if we get a hw irq event on an illegal vector?
 287  * Each architecture has to answer this themself.
 288  */
 289 static void ack_bad(unsigned int irq)
 290 {
 291         struct irq_desc *desc = irq_to_desc(irq);
 292
 293         print_irq_desc(irq, desc);
 294         ack_bad_irq(irq);
 295 }
 296
 297 /*
 298  * NOP functions
 299  */
 300 static void noop(unsigned int irq)
 301 {
 302 }
 303
 304 static unsigned int noop_ret(unsigned int irq)
 305 {
 306         return 0;
 307 }
 308
 309 /*
 310  * Generic no controller implementation
 311  */
 312 struct irq_chip no_irq_chip = {
 313         .name           = "none",
 314         .startup        = noop_ret,
 315         .shutdown       = noop,
 316         .enable         = noop,
 317         .disable        = noop,
 318         .ack            = ack_bad,
 319         .end            = noop,
 320 };
 321
 322 /*
 323  * Generic dummy implementation which can be used for
 324  * real dumb interrupt sources
 325  */
 326 struct irq_chip dummy_irq_chip = {
 327         .name           = "dummy",
 328         .startup        = noop_ret,
 329         .shutdown       = noop,
 330         .enable         = noop,
 331         .disable        = noop,
 332         .ack            = noop,
 333         .mask           = noop,
 334         .unmask         = noop,
 335         .end            = noop,
 336 };
 337
 338 /*
 339  * Special, empty irq handler:
 340  */
 341 irqreturn_t no_action(int cpl, void *dev_id)
 342 {
 343         return IRQ_NONE;
 344 }
 345
 346 static void warn_no_thread(unsigned int irq, struct irqaction *action)
 347 {
 348         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
 349                 return;
 350
 351         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
 352                "but no thread function available.", irq, action->name);
 353 }
 354
 355 /**
 356  * handle_IRQ_event - irq action chain handler
 357  * @irq:        the interrupt number
 358  * @action:     the interrupt action chain for this irq
 359  *
 360  * Handles the action chain of an irq event
 361  */
 362 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 363 {
 364         irqreturn_t ret, retval = IRQ_NONE;
 365         unsigned int status = 0;
 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                 if (likely(!(desc->status & IRQ_DISABLED))) {
 460                         action_ret = handle_IRQ_event(irq, desc->action);
 461                         if (!noirqdebug)
 462                                 note_interrupt(irq, desc, action_ret);
 463                 }
 464                 desc->chip->end(irq);
 465                 return 1;
 466         }
 467
 468         raw_spin_lock(&desc->lock);
 469         if (desc->chip->ack)
 470                 desc->chip->ack(irq);
 471         /*
 472          * REPLAY is when Linux resends an IRQ that was dropped earlier
 473          * WAITING is used by probe to mark irqs that are being tested
 474          */
 475         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 476         status |= IRQ_PENDING; /* we _want_ to handle it */
 477
 478         /*
 479          * If the IRQ is disabled for whatever reason, we cannot
 480          * use the action we have.
 481          */
 482         action = NULL;
 483         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 484                 action = desc->action;
 485                 status &= ~IRQ_PENDING; /* we commit to handling */
 486                 status |= IRQ_INPROGRESS; /* we are handling it */
 487         }
 488         desc->status = status;
 489
 490         /*
 491          * If there is no IRQ handler or it was disabled, exit early.
 492          * Since we set PENDING, if another processor is handling
 493          * a different instance of this same irq, the other processor
 494          * will take care of it.
 495          */
 496         if (unlikely(!action))
 497                 goto out;
 498
 499         /*
 500          * Edge triggered interrupts need to remember
 501          * pending events.
 502          * This applies to any hw interrupts that allow a second
 503          * instance of the same irq to arrive while we are in do_IRQ
 504          * or in the handler. But the code here only handles the _second_
 505          * instance of the irq, not the third or fourth. So it is mostly
 506          * useful for irq hardware that does not mask cleanly in an
 507          * SMP environment.
 508          */
 509         for (;;) {
 510                 irqreturn_t action_ret;
 511
 512                 raw_spin_unlock(&desc->lock);
 513
 514                 action_ret = handle_IRQ_event(irq, action);
 515                 if (!noirqdebug)
 516                         note_interrupt(irq, desc, action_ret);
 517
 518                 raw_spin_lock(&desc->lock);
 519                 if (likely(!(desc->status & IRQ_PENDING)))
 520                         break;
 521                 desc->status &= ~IRQ_PENDING;
 522         }
 523         desc->status &= ~IRQ_INPROGRESS;
 524
 525 out:
 526         /*
 527          * The ->end() handler has to deal with interrupts which got
 528          * disabled while the handler was running.
 529          */
 530         desc->chip->end(irq);
 531         raw_spin_unlock(&desc->lock);
 532
 533         return 1;
 534 }
 535 #endif
 536
 537 void early_init_irq_lock_class(void)
 538 {
 539         struct irq_desc *desc;
 540         int i;
 541
 542         for_each_irq_desc(i, desc) {
 543                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 544         }
 545 }
 546
 547 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 548 {
 549         struct irq_desc *desc = irq_to_desc(irq);
 550         return desc ? desc->kstat_irqs[cpu] : 0;
 551 }
 552 EXPORT_SYMBOL(kstat_irqs_cpu);
 553