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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 <linux/bootmem.h>
  23 #include <trace/events/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_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
  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 __ref init_kstat_irqs(struct irq_desc *desc, int node, int nr)
  87 {
  88         void *ptr;
  89
  90         if (slab_is_available())
  91                 ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
  92                                    GFP_ATOMIC, node);
  93         else
  94                 ptr = alloc_bootmem_node(NODE_DATA(node),
  95                                 nr * sizeof(*desc->kstat_irqs));
  96
  97         /*
  98          * don't overwite if can not get new one
  99          * init_copy_kstat_irqs() could still use old one
 100          */
 101         if (ptr) {
 102                 printk(KERN_DEBUG "  alloc kstat_irqs on node %d\n", node);
 103                 desc->kstat_irqs = ptr;
 104         }
 105 }
 106
 107 static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
 108 {
 109         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 110
 111         spin_lock_init(&desc->lock);
 112         desc->irq = irq;
 113 #ifdef CONFIG_SMP
 114         desc->node = node;
 115 #endif
 116         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 117         init_kstat_irqs(desc, node, nr_cpu_ids);
 118         if (!desc->kstat_irqs) {
 119                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 120                 BUG_ON(1);
 121         }
 122         if (!alloc_desc_masks(desc, node, false)) {
 123                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 124                 BUG_ON(1);
 125         }
 126         init_desc_masks(desc);
 127         arch_init_chip_data(desc, node);
 128 }
 129
 130 /*
 131  * Protect the sparse_irqs:
 132  */
 133 DEFINE_SPINLOCK(sparse_irq_lock);
 134
 135 struct irq_desc **irq_desc_ptrs __read_mostly;
 136
 137 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 138         [0 ... NR_IRQS_LEGACY-1] = {
 139                 .irq        = -1,
 140                 .status     = IRQ_DISABLED,
 141                 .chip       = &no_irq_chip,
 142                 .handle_irq = handle_bad_irq,
 143                 .depth      = 1,
 144                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 145         }
 146 };
 147
 148 static unsigned int *kstat_irqs_legacy;
 149
 150 int __init early_irq_init(void)
 151 {
 152         struct irq_desc *desc;
 153         int legacy_count;
 154         int node;
 155         int i;
 156
 157         init_irq_default_affinity();
 158
 159          /* initialize nr_irqs based on nr_cpu_ids */
 160         arch_probe_nr_irqs();
 161         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 162
 163         desc = irq_desc_legacy;
 164         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 165         node = first_online_node;
 166
 167         /* allocate irq_desc_ptrs array based on nr_irqs */
 168         irq_desc_ptrs = kcalloc(nr_irqs, sizeof(void *), GFP_NOWAIT);
 169
 170         /* allocate based on nr_cpu_ids */
 171         kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
 172                                           sizeof(int), GFP_NOWAIT, node);
 173
 174         for (i = 0; i < legacy_count; i++) {
 175                 desc[i].irq = i;
 176 #ifdef CONFIG_SMP
 177                 desc[i].node = node;
 178 #endif
 179                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 180                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 181                 alloc_desc_masks(&desc[i], node, true);
 182                 init_desc_masks(&desc[i]);
 183                 irq_desc_ptrs[i] = desc + i;
 184         }
 185
 186         for (i = legacy_count; i < nr_irqs; i++)
 187                 irq_desc_ptrs[i] = NULL;
 188
 189         return arch_early_irq_init();
 190 }
 191
 192 struct irq_desc *irq_to_desc(unsigned int irq)
 193 {
 194         if (irq_desc_ptrs && irq < nr_irqs)
 195                 return irq_desc_ptrs[irq];
 196
 197         return NULL;
 198 }
 199
 200 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 201 {
 202         struct irq_desc *desc;
 203         unsigned long flags;
 204
 205         if (irq >= nr_irqs) {
 206                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 207                         irq, nr_irqs);
 208                 return NULL;
 209         }
 210
 211         desc = irq_desc_ptrs[irq];
 212         if (desc)
 213                 return desc;
 214
 215         spin_lock_irqsave(&sparse_irq_lock, flags);
 216
 217         /* We have to check it to avoid races with another CPU */
 218         desc = irq_desc_ptrs[irq];
 219         if (desc)
 220                 goto out_unlock;
 221
 222         if (slab_is_available())
 223                 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 224         else
 225                 desc = alloc_bootmem_node(NODE_DATA(node), sizeof(*desc));
 226
 227         printk(KERN_DEBUG "  alloc irq_desc for %d on node %d\n", irq, node);
 228         if (!desc) {
 229                 printk(KERN_ERR "can not alloc irq_desc\n");
 230                 BUG_ON(1);
 231         }
 232         init_one_irq_desc(irq, desc, node);
 233
 234         irq_desc_ptrs[irq] = desc;
 235
 236 out_unlock:
 237         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 238
 239         return desc;
 240 }
 241
 242 #else /* !CONFIG_SPARSE_IRQ */
 243
 244 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 245         [0 ... NR_IRQS-1] = {
 246                 .status = IRQ_DISABLED,
 247                 .chip = &no_irq_chip,
 248                 .handle_irq = handle_bad_irq,
 249                 .depth = 1,
 250                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 251         }
 252 };
 253
 254 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 255 int __init early_irq_init(void)
 256 {
 257         struct irq_desc *desc;
 258         int count;
 259         int i;
 260
 261         init_irq_default_affinity();
 262
 263         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 264
 265         desc = irq_desc;
 266         count = ARRAY_SIZE(irq_desc);
 267
 268         for (i = 0; i < count; i++) {
 269                 desc[i].irq = i;
 270                 alloc_desc_masks(&desc[i], 0, true);
 271                 init_desc_masks(&desc[i]);
 272                 desc[i].kstat_irqs = kstat_irqs_all[i];
 273         }
 274         return arch_early_irq_init();
 275 }
 276
 277 struct irq_desc *irq_to_desc(unsigned int irq)
 278 {
 279         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 280 }
 281
 282 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 283 {
 284         return irq_to_desc(irq);
 285 }
 286 #endif /* !CONFIG_SPARSE_IRQ */
 287
 288 void clear_kstat_irqs(struct irq_desc *desc)
 289 {
 290         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 291 }
 292
 293 /*
 294  * What should we do if we get a hw irq event on an illegal vector?
 295  * Each architecture has to answer this themself.
 296  */
 297 static void ack_bad(unsigned int irq)
 298 {
 299         struct irq_desc *desc = irq_to_desc(irq);
 300
 301         print_irq_desc(irq, desc);
 302         ack_bad_irq(irq);
 303 }
 304
 305 /*
 306  * NOP functions
 307  */
 308 static void noop(unsigned int irq)
 309 {
 310 }
 311
 312 static unsigned int noop_ret(unsigned int irq)
 313 {
 314         return 0;
 315 }
 316
 317 /*
 318  * Generic no controller implementation
 319  */
 320 struct irq_chip no_irq_chip = {
 321         .name           = "none",
 322         .startup        = noop_ret,
 323         .shutdown       = noop,
 324         .enable         = noop,
 325         .disable        = noop,
 326         .ack            = ack_bad,
 327         .end            = noop,
 328 };
 329
 330 /*
 331  * Generic dummy implementation which can be used for
 332  * real dumb interrupt sources
 333  */
 334 struct irq_chip dummy_irq_chip = {
 335         .name           = "dummy",
 336         .startup        = noop_ret,
 337         .shutdown       = noop,
 338         .enable         = noop,
 339         .disable        = noop,
 340         .ack            = noop,
 341         .mask           = noop,
 342         .unmask         = noop,
 343         .end            = noop,
 344 };
 345
 346 /*
 347  * Special, empty irq handler:
 348  */
 349 irqreturn_t no_action(int cpl, void *dev_id)
 350 {
 351         return IRQ_NONE;
 352 }
 353
 354 static void warn_no_thread(unsigned int irq, struct irqaction *action)
 355 {
 356         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
 357                 return;
 358
 359         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
 360                "but no thread function available.", irq, action->name);
 361 }
 362
 363 /**
 364  * handle_IRQ_event - irq action chain handler
 365  * @irq:        the interrupt number
 366  * @action:     the interrupt action chain for this irq
 367  *
 368  * Handles the action chain of an irq event
 369  */
 370 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 371 {
 372         irqreturn_t ret, retval = IRQ_NONE;
 373         unsigned int status = 0;
 374
 375         if (!(action->flags & IRQF_DISABLED))
 376                 local_irq_enable_in_hardirq();
 377
 378         do {
 379                 trace_irq_handler_entry(irq, action);
 380                 ret = action->handler(irq, action->dev_id);
 381                 trace_irq_handler_exit(irq, action, ret);
 382
 383                 switch (ret) {
 384                 case IRQ_WAKE_THREAD:
 385                         /*
 386                          * Set result to handled so the spurious check
 387                          * does not trigger.
 388                          */
 389                         ret = IRQ_HANDLED;
 390
 391                         /*
 392                          * Catch drivers which return WAKE_THREAD but
 393                          * did not set up a thread function
 394                          */
 395                         if (unlikely(!action->thread_fn)) {
 396                                 warn_no_thread(irq, action);
 397                                 break;
 398                         }
 399
 400                         /*
 401                          * Wake up the handler thread for this
 402                          * action. In case the thread crashed and was
 403                          * killed we just pretend that we handled the
 404                          * interrupt. The hardirq handler above has
 405                          * disabled the device interrupt, so no irq
 406                          * storm is lurking.
 407                          */
 408                         if (likely(!test_bit(IRQTF_DIED,
 409                                              &action->thread_flags))) {
 410                                 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
 411                                 wake_up_process(action->thread);
 412                         }
 413
 414                         /* Fall through to add to randomness */
 415                 case IRQ_HANDLED:
 416                         status |= action->flags;
 417                         break;
 418
 419                 default:
 420                         break;
 421                 }
 422
 423                 retval |= ret;
 424                 action = action->next;
 425         } while (action);
 426
 427         if (status & IRQF_SAMPLE_RANDOM)
 428                 add_interrupt_randomness(irq);
 429         local_irq_disable();
 430
 431         return retval;
 432 }
 433
 434 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 435
 436 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
 437 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
 438 #endif
 439
 440 /**
 441  * __do_IRQ - original all in one highlevel IRQ handler
 442  * @irq:        the interrupt number
 443  *
 444  * __do_IRQ handles all normal device IRQ's (the special
 445  * SMP cross-CPU interrupts have their own specific
 446  * handlers).
 447  *
 448  * This is the original x86 implementation which is used for every
 449  * interrupt type.
 450  */
 451 unsigned int __do_IRQ(unsigned int irq)
 452 {
 453         struct irq_desc *desc = irq_to_desc(irq);
 454         struct irqaction *action;
 455         unsigned int status;
 456
 457         kstat_incr_irqs_this_cpu(irq, desc);
 458
 459         if (CHECK_IRQ_PER_CPU(desc->status)) {
 460                 irqreturn_t action_ret;
 461
 462                 /*
 463                  * No locking required for CPU-local interrupts:
 464                  */
 465                 if (desc->chip->ack)
 466                         desc->chip->ack(irq);
 467                 if (likely(!(desc->status & IRQ_DISABLED))) {
 468                         action_ret = handle_IRQ_event(irq, desc->action);
 469                         if (!noirqdebug)
 470                                 note_interrupt(irq, desc, action_ret);
 471                 }
 472                 desc->chip->end(irq);
 473                 return 1;
 474         }
 475
 476         spin_lock(&desc->lock);
 477         if (desc->chip->ack)
 478                 desc->chip->ack(irq);
 479         /*
 480          * REPLAY is when Linux resends an IRQ that was dropped earlier
 481          * WAITING is used by probe to mark irqs that are being tested
 482          */
 483         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 484         status |= IRQ_PENDING; /* we _want_ to handle it */
 485
 486         /*
 487          * If the IRQ is disabled for whatever reason, we cannot
 488          * use the action we have.
 489          */
 490         action = NULL;
 491         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 492                 action = desc->action;
 493                 status &= ~IRQ_PENDING; /* we commit to handling */
 494                 status |= IRQ_INPROGRESS; /* we are handling it */
 495         }
 496         desc->status = status;
 497
 498         /*
 499          * If there is no IRQ handler or it was disabled, exit early.
 500          * Since we set PENDING, if another processor is handling
 501          * a different instance of this same irq, the other processor
 502          * will take care of it.
 503          */
 504         if (unlikely(!action))
 505                 goto out;
 506
 507         /*
 508          * Edge triggered interrupts need to remember
 509          * pending events.
 510          * This applies to any hw interrupts that allow a second
 511          * instance of the same irq to arrive while we are in do_IRQ
 512          * or in the handler. But the code here only handles the _second_
 513          * instance of the irq, not the third or fourth. So it is mostly
 514          * useful for irq hardware that does not mask cleanly in an
 515          * SMP environment.
 516          */
 517         for (;;) {
 518                 irqreturn_t action_ret;
 519
 520                 spin_unlock(&desc->lock);
 521
 522                 action_ret = handle_IRQ_event(irq, action);
 523                 if (!noirqdebug)
 524                         note_interrupt(irq, desc, action_ret);
 525
 526                 spin_lock(&desc->lock);
 527                 if (likely(!(desc->status & IRQ_PENDING)))
 528                         break;
 529                 desc->status &= ~IRQ_PENDING;
 530         }
 531         desc->status &= ~IRQ_INPROGRESS;
 532
 533 out:
 534         /*
 535          * The ->end() handler has to deal with interrupts which got
 536          * disabled while the handler was running.
 537          */
 538         desc->chip->end(irq);
 539         spin_unlock(&desc->lock);
 540
 541         return 1;
 542 }
 543 #endif
 544
 545 void early_init_irq_lock_class(void)
 546 {
 547         struct irq_desc *desc;
 548         int i;
 549
 550         for_each_irq_desc(i, desc) {
 551                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 552         }
 553 }
 554
 555 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 556 {
 557         struct irq_desc *desc = irq_to_desc(irq);
 558         return desc ? desc->kstat_irqs[cpu] : 0;
 559 }
 560 EXPORT_SYMBOL(kstat_irqs_cpu);
 561