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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/radix-tree.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       = __RAW_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         ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs),
  91                            GFP_ATOMIC, node);
  92
  93         /*
  94          * don't overwite if can not get new one
  95          * init_copy_kstat_irqs() could still use old one
  96          */
  97         if (ptr) {
  98                 printk(KERN_DEBUG "  alloc kstat_irqs on node %d\n", node);
  99                 desc->kstat_irqs = ptr;
 100         }
 101 }
 102
 103 static void init_one_irq_desc(int irq, struct irq_desc *desc, int node)
 104 {
 105         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 106
 107         raw_spin_lock_init(&desc->lock);
 108         desc->irq = irq;
 109 #ifdef CONFIG_SMP
 110         desc->node = node;
 111 #endif
 112         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 113         init_kstat_irqs(desc, node, nr_cpu_ids);
 114         if (!desc->kstat_irqs) {
 115                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 116                 BUG_ON(1);
 117         }
 118         if (!alloc_desc_masks(desc, node, false)) {
 119                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 120                 BUG_ON(1);
 121         }
 122         init_desc_masks(desc);
 123         arch_init_chip_data(desc, node);
 124 }
 125
 126 /*
 127  * Protect the sparse_irqs:
 128  */
 129 DEFINE_RAW_SPINLOCK(sparse_irq_lock);
 130
 131 static RADIX_TREE(irq_desc_tree, GFP_ATOMIC);
 132
 133 static void set_irq_desc(unsigned int irq, struct irq_desc *desc)
 134 {
 135         radix_tree_insert(&irq_desc_tree, irq, desc);
 136 }
 137
 138 struct irq_desc *irq_to_desc(unsigned int irq)
 139 {
 140         return radix_tree_lookup(&irq_desc_tree, irq);
 141 }
 142
 143 void replace_irq_desc(unsigned int irq, struct irq_desc *desc)
 144 {
 145         void **ptr;
 146
 147         ptr = radix_tree_lookup_slot(&irq_desc_tree, irq);
 148         if (ptr)
 149                 radix_tree_replace_slot(ptr, desc);
 150 }
 151
 152 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 153         [0 ... NR_IRQS_LEGACY-1] = {
 154                 .irq        = -1,
 155                 .status     = IRQ_DISABLED,
 156                 .chip       = &no_irq_chip,
 157                 .handle_irq = handle_bad_irq,
 158                 .depth      = 1,
 159                 .lock       = __RAW_SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 160         }
 161 };
 162
 163 static unsigned int *kstat_irqs_legacy;
 164
 165 int __init early_irq_init(void)
 166 {
 167         struct irq_desc *desc;
 168         int legacy_count;
 169         int node;
 170         int i;
 171
 172         init_irq_default_affinity();
 173
 174          /* initialize nr_irqs based on nr_cpu_ids */
 175         arch_probe_nr_irqs();
 176         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 177
 178         desc = irq_desc_legacy;
 179         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 180         node = first_online_node;
 181
 182         /* allocate based on nr_cpu_ids */
 183         kstat_irqs_legacy = kzalloc_node(NR_IRQS_LEGACY * nr_cpu_ids *
 184                                           sizeof(int), GFP_NOWAIT, node);
 185
 186         for (i = 0; i < legacy_count; i++) {
 187                 desc[i].irq = i;
 188 #ifdef CONFIG_SMP
 189                 desc[i].node = node;
 190 #endif
 191                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 192                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 193                 alloc_desc_masks(&desc[i], node, true);
 194                 init_desc_masks(&desc[i]);
 195                 set_irq_desc(i, &desc[i]);
 196         }
 197
 198         return arch_early_irq_init();
 199 }
 200
 201 struct irq_desc * __ref irq_to_desc_alloc_node(unsigned int irq, int node)
 202 {
 203         struct irq_desc *desc;
 204         unsigned long flags;
 205
 206         if (irq >= nr_irqs) {
 207                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 208                         irq, nr_irqs);
 209                 return NULL;
 210         }
 211
 212         desc = irq_to_desc(irq);
 213         if (desc)
 214                 return desc;
 215
 216         raw_spin_lock_irqsave(&sparse_irq_lock, flags);
 217
 218         /* We have to check it to avoid races with another CPU */
 219         desc = irq_to_desc(irq);
 220         if (desc)
 221                 goto out_unlock;
 222
 223         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 224
 225         printk(KERN_DEBUG "  alloc irq_desc for %d on node %d\n", irq, node);
 226         if (!desc) {
 227                 printk(KERN_ERR "can not alloc irq_desc\n");
 228                 BUG_ON(1);
 229         }
 230         init_one_irq_desc(irq, desc, node);
 231
 232         set_irq_desc(irq, desc);
 233
 234 out_unlock:
 235         raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
 236
 237         return desc;
 238 }
 239
 240 #else /* !CONFIG_SPARSE_IRQ */
 241
 242 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 243         [0 ... NR_IRQS-1] = {
 244                 .status = IRQ_DISABLED,
 245                 .chip = &no_irq_chip,
 246                 .handle_irq = handle_bad_irq,
 247                 .depth = 1,
 248                 .lock = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
 249         }
 250 };
 251
 252 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 253 int __init early_irq_init(void)
 254 {
 255         struct irq_desc *desc;
 256         int count;
 257         int i;
 258
 259         init_irq_default_affinity();
 260
 261         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 262
 263         desc = irq_desc;
 264         count = ARRAY_SIZE(irq_desc);
 265
 266         for (i = 0; i < count; i++) {
 267                 desc[i].irq = i;
 268                 alloc_desc_masks(&desc[i], 0, true);
 269                 init_desc_masks(&desc[i]);
 270                 desc[i].kstat_irqs = kstat_irqs_all[i];
 271         }
 272         return arch_early_irq_init();
 273 }
 274
 275 struct irq_desc *irq_to_desc(unsigned int irq)
 276 {
 277         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 278 }
 279
 280 struct irq_desc *irq_to_desc_alloc_node(unsigned int irq, int node)
 281 {
 282         return irq_to_desc(irq);
 283 }
 284 #endif /* !CONFIG_SPARSE_IRQ */
 285
 286 void clear_kstat_irqs(struct irq_desc *desc)
 287 {
 288         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 289 }
 290
 291 /*
 292  * What should we do if we get a hw irq event on an illegal vector?
 293  * Each architecture has to answer this themself.
 294  */
 295 static void ack_bad(unsigned int irq)
 296 {
 297         struct irq_desc *desc = irq_to_desc(irq);
 298
 299         print_irq_desc(irq, desc);
 300         ack_bad_irq(irq);
 301 }
 302
 303 /*
 304  * NOP functions
 305  */
 306 static void noop(unsigned int irq)
 307 {
 308 }
 309
 310 static unsigned int noop_ret(unsigned int irq)
 311 {
 312         return 0;
 313 }
 314
 315 /*
 316  * Generic no controller implementation
 317  */
 318 struct irq_chip no_irq_chip = {
 319         .name           = "none",
 320         .startup        = noop_ret,
 321         .shutdown       = noop,
 322         .enable         = noop,
 323         .disable        = noop,
 324         .ack            = ack_bad,
 325         .end            = noop,
 326 };
 327
 328 /*
 329  * Generic dummy implementation which can be used for
 330  * real dumb interrupt sources
 331  */
 332 struct irq_chip dummy_irq_chip = {
 333         .name           = "dummy",
 334         .startup        = noop_ret,
 335         .shutdown       = noop,
 336         .enable         = noop,
 337         .disable        = noop,
 338         .ack            = noop,
 339         .mask           = noop,
 340         .unmask         = noop,
 341         .end            = noop,
 342 };
 343
 344 /*
 345  * Special, empty irq handler:
 346  */
 347 irqreturn_t no_action(int cpl, void *dev_id)
 348 {
 349         return IRQ_NONE;
 350 }
 351
 352 static void warn_no_thread(unsigned int irq, struct irqaction *action)
 353 {
 354         if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
 355                 return;
 356
 357         printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
 358                "but no thread function available.", irq, action->name);
 359 }
 360
 361 /**
 362  * handle_IRQ_event - irq action chain handler
 363  * @irq:        the interrupt number
 364  * @action:     the interrupt action chain for this irq
 365  *
 366  * Handles the action chain of an irq event
 367  */
 368 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 369 {
 370         irqreturn_t ret, retval = IRQ_NONE;
 371         unsigned int status = 0;
 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         raw_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                 raw_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                 raw_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         raw_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