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