kernel/irq/handle.c

   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/module.h>
  15 #include <linux/random.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel_stat.h>
  18 #include <linux/rculist.h>
  19 #include <linux/hash.h>
  20 #include <trace/irq.h>
  21 #include <linux/bootmem.h>
  22
  23 #include "internals.h"
  24
  25 /*
  26  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  27  */
  28 struct lock_class_key irq_desc_lock_class;
  29
  30 /**
  31  * handle_bad_irq - handle spurious and unhandled irqs
  32  * @irq:       the interrupt number
  33  * @desc:      description of the interrupt
  34  *
  35  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  36  */
  37 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  38 {
  39         print_irq_desc(irq, desc);
  40         kstat_incr_irqs_this_cpu(irq, desc);
  41         ack_bad_irq(irq);
  42 }
  43
  44 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
  45 static void __init init_irq_default_affinity(void)
  46 {
  47         alloc_bootmem_cpumask_var(&irq_default_affinity);
  48         cpumask_setall(irq_default_affinity);
  49 }
  50 #else
  51 static void __init init_irq_default_affinity(void)
  52 {
  53 }
  54 #endif
  55
  56 /*
  57  * Linux has a controller-independent interrupt architecture.
  58  * Every controller has a 'controller-template', that is used
  59  * by the main code to do the right thing. Each driver-visible
  60  * interrupt source is transparently wired to the appropriate
  61  * controller. Thus drivers need not be aware of the
  62  * interrupt-controller.
  63  *
  64  * The code is designed to be easily extended with new/different
  65  * interrupt controllers, without having to do assembly magic or
  66  * having to touch the generic code.
  67  *
  68  * Controller mappings for all interrupt sources:
  69  */
  70 int nr_irqs = NR_IRQS;
  71 EXPORT_SYMBOL_GPL(nr_irqs);
  72
  73 #ifdef CONFIG_SPARSE_IRQ
  74
  75 static struct irq_desc irq_desc_init = {
  76         .irq        = -1,
  77         .status     = IRQ_DISABLED,
  78         .chip       = &no_irq_chip,
  79         .handle_irq = handle_bad_irq,
  80         .depth      = 1,
  81         .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  82 };
  83
  84 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
  85 {
  86         unsigned long bytes;
  87         char *ptr;
  88         int node;
  89
  90         /* Compute how many bytes we need per irq and allocate them */
  91         bytes = nr * sizeof(unsigned int);
  92
  93         node = cpu_to_node(cpu);
  94         ptr = kzalloc_node(bytes, GFP_ATOMIC, node);
  95         printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n", cpu, node);
  96
  97         if (ptr)
  98                 desc->kstat_irqs = (unsigned int *)ptr;
  99 }
 100
 101 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
 102 {
 103         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 104
 105         spin_lock_init(&desc->lock);
 106         desc->irq = irq;
 107 #ifdef CONFIG_SMP
 108         desc->cpu = cpu;
 109 #endif
 110         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 111         init_kstat_irqs(desc, cpu, nr_cpu_ids);
 112         if (!desc->kstat_irqs) {
 113                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 114                 BUG_ON(1);
 115         }
 116         if (!init_alloc_desc_masks(desc, cpu, false)) {
 117                 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
 118                 BUG_ON(1);
 119         }
 120         arch_init_chip_data(desc, cpu);
 121 }
 122
 123 /*
 124  * Protect the sparse_irqs:
 125  */
 126 DEFINE_SPINLOCK(sparse_irq_lock);
 127
 128 struct irq_desc **irq_desc_ptrs __read_mostly;
 129
 130 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 131         [0 ... NR_IRQS_LEGACY-1] = {
 132                 .irq        = -1,
 133                 .status     = IRQ_DISABLED,
 134                 .chip       = &no_irq_chip,
 135                 .handle_irq = handle_bad_irq,
 136                 .depth      = 1,
 137                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 138         }
 139 };
 140
 141 static unsigned int *kstat_irqs_legacy;
 142
 143 int __init early_irq_init(void)
 144 {
 145         struct irq_desc *desc;
 146         int legacy_count;
 147         int i;
 148
 149         init_irq_default_affinity();
 150
 151          /* initialize nr_irqs based on nr_cpu_ids */
 152         arch_probe_nr_irqs();
 153         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 154
 155         desc = irq_desc_legacy;
 156         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 157
 158         /* allocate irq_desc_ptrs array based on nr_irqs */
 159         irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
 160
 161         /* allocate based on nr_cpu_ids */
 162         /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
 163         kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
 164                                           sizeof(int));
 165
 166         for (i = 0; i < legacy_count; i++) {
 167                 desc[i].irq = i;
 168                 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
 169                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 170                 init_alloc_desc_masks(&desc[i], 0, true);
 171                 irq_desc_ptrs[i] = desc + i;
 172         }
 173
 174         for (i = legacy_count; i < nr_irqs; i++)
 175                 irq_desc_ptrs[i] = NULL;
 176
 177         return arch_early_irq_init();
 178 }
 179
 180 struct irq_desc *irq_to_desc(unsigned int irq)
 181 {
 182         if (irq_desc_ptrs && irq < nr_irqs)
 183                 return irq_desc_ptrs[irq];
 184
 185         return NULL;
 186 }
 187
 188 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 189 {
 190         struct irq_desc *desc;
 191         unsigned long flags;
 192         int node;
 193
 194         if (irq >= nr_irqs) {
 195                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 196                         irq, nr_irqs);
 197                 return NULL;
 198         }
 199
 200         desc = irq_desc_ptrs[irq];
 201         if (desc)
 202                 return desc;
 203
 204         spin_lock_irqsave(&sparse_irq_lock, flags);
 205
 206         /* We have to check it to avoid races with another CPU */
 207         desc = irq_desc_ptrs[irq];
 208         if (desc)
 209                 goto out_unlock;
 210
 211         node = cpu_to_node(cpu);
 212         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 213         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
 214                  irq, cpu, node);
 215         if (!desc) {
 216                 printk(KERN_ERR "can not alloc irq_desc\n");
 217                 BUG_ON(1);
 218         }
 219         init_one_irq_desc(irq, desc, cpu);
 220
 221         irq_desc_ptrs[irq] = desc;
 222
 223 out_unlock:
 224         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 225
 226         return desc;
 227 }
 228
 229 #else /* !CONFIG_SPARSE_IRQ */
 230
 231 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 232         [0 ... NR_IRQS-1] = {
 233                 .status = IRQ_DISABLED,
 234                 .chip = &no_irq_chip,
 235                 .handle_irq = handle_bad_irq,
 236                 .depth = 1,
 237                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 238         }
 239 };
 240
 241 int __init early_irq_init(void)
 242 {
 243         struct irq_desc *desc;
 244         int count;
 245         int i;
 246
 247         init_irq_default_affinity();
 248
 249         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 250
 251         desc = irq_desc;
 252         count = ARRAY_SIZE(irq_desc);
 253
 254         for (i = 0; i < count; i++) {
 255                 desc[i].irq = i;
 256                 init_alloc_desc_masks(&desc[i], 0, true);
 257         }
 258         return arch_early_irq_init();
 259 }
 260
 261 struct irq_desc *irq_to_desc(unsigned int irq)
 262 {
 263         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 264 }
 265
 266 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 267 {
 268         return irq_to_desc(irq);
 269 }
 270 #endif /* !CONFIG_SPARSE_IRQ */
 271
 272 /*
 273  * What should we do if we get a hw irq event on an illegal vector?
 274  * Each architecture has to answer this themself.
 275  */
 276 static void ack_bad(unsigned int irq)
 277 {
 278         struct irq_desc *desc = irq_to_desc(irq);
 279
 280         print_irq_desc(irq, desc);
 281         ack_bad_irq(irq);
 282 }
 283
 284 /*
 285  * NOP functions
 286  */
 287 static void noop(unsigned int irq)
 288 {
 289 }
 290
 291 static unsigned int noop_ret(unsigned int irq)
 292 {
 293         return 0;
 294 }
 295
 296 /*
 297  * Generic no controller implementation
 298  */
 299 struct irq_chip no_irq_chip = {
 300         .name           = "none",
 301         .startup        = noop_ret,
 302         .shutdown       = noop,
 303         .enable         = noop,
 304         .disable        = noop,
 305         .ack            = ack_bad,
 306         .end            = noop,
 307 };
 308
 309 /*
 310  * Generic dummy implementation which can be used for
 311  * real dumb interrupt sources
 312  */
 313 struct irq_chip dummy_irq_chip = {
 314         .name           = "dummy",
 315         .startup        = noop_ret,
 316         .shutdown       = noop,
 317         .enable         = noop,
 318         .disable        = noop,
 319         .ack            = noop,
 320         .mask           = noop,
 321         .unmask         = noop,
 322         .end            = noop,
 323 };
 324
 325 /*
 326  * Special, empty irq handler:
 327  */
 328 irqreturn_t no_action(int cpl, void *dev_id)
 329 {
 330         return IRQ_NONE;
 331 }
 332
 333 DEFINE_TRACE(irq_handler_entry);
 334 DEFINE_TRACE(irq_handler_exit);
 335
 336 /**
 337  * handle_IRQ_event - irq action chain handler
 338  * @irq:        the interrupt number
 339  * @action:     the interrupt action chain for this irq
 340  *
 341  * Handles the action chain of an irq event
 342  */
 343 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 344 {
 345         irqreturn_t ret, retval = IRQ_NONE;
 346         unsigned int status = 0;
 347
 348         if (!(action->flags & IRQF_DISABLED))
 349                 local_irq_enable_in_hardirq();
 350
 351         do {
 352                 trace_irq_handler_entry(irq, action);
 353                 ret = action->handler(irq, action->dev_id);
 354                 trace_irq_handler_exit(irq, action, ret);
 355                 if (ret == IRQ_HANDLED)
 356                         status |= action->flags;
 357                 retval |= ret;
 358                 action = action->next;
 359         } while (action);
 360
 361         if (status & IRQF_SAMPLE_RANDOM)
 362                 add_interrupt_randomness(irq);
 363         local_irq_disable();
 364
 365         return retval;
 366 }
 367
 368 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 369 /**
 370  * __do_IRQ - original all in one highlevel IRQ handler
 371  * @irq:        the interrupt number
 372  *
 373  * __do_IRQ handles all normal device IRQ's (the special
 374  * SMP cross-CPU interrupts have their own specific
 375  * handlers).
 376  *
 377  * This is the original x86 implementation which is used for every
 378  * interrupt type.
 379  */
 380 unsigned int __do_IRQ(unsigned int irq)
 381 {
 382         struct irq_desc *desc = irq_to_desc(irq);
 383         struct irqaction *action;
 384         unsigned int status;
 385
 386         kstat_incr_irqs_this_cpu(irq, desc);
 387
 388         if (CHECK_IRQ_PER_CPU(desc->status)) {
 389                 irqreturn_t action_ret;
 390
 391                 /*
 392                  * No locking required for CPU-local interrupts:
 393                  */
 394                 if (desc->chip->ack) {
 395                         desc->chip->ack(irq);
 396                         /* get new one */
 397                         desc = irq_remap_to_desc(irq, desc);
 398                 }
 399                 if (likely(!(desc->status & IRQ_DISABLED))) {
 400                         action_ret = handle_IRQ_event(irq, desc->action);
 401                         if (!noirqdebug)
 402                                 note_interrupt(irq, desc, action_ret);
 403                 }
 404                 desc->chip->end(irq);
 405                 return 1;
 406         }
 407
 408         spin_lock(&desc->lock);
 409         if (desc->chip->ack) {
 410                 desc->chip->ack(irq);
 411                 desc = irq_remap_to_desc(irq, desc);
 412         }
 413         /*
 414          * REPLAY is when Linux resends an IRQ that was dropped earlier
 415          * WAITING is used by probe to mark irqs that are being tested
 416          */
 417         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 418         status |= IRQ_PENDING; /* we _want_ to handle it */
 419
 420         /*
 421          * If the IRQ is disabled for whatever reason, we cannot
 422          * use the action we have.
 423          */
 424         action = NULL;
 425         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 426                 action = desc->action;
 427                 status &= ~IRQ_PENDING; /* we commit to handling */
 428                 status |= IRQ_INPROGRESS; /* we are handling it */
 429         }
 430         desc->status = status;
 431
 432         /*
 433          * If there is no IRQ handler or it was disabled, exit early.
 434          * Since we set PENDING, if another processor is handling
 435          * a different instance of this same irq, the other processor
 436          * will take care of it.
 437          */
 438         if (unlikely(!action))
 439                 goto out;
 440
 441         /*
 442          * Edge triggered interrupts need to remember
 443          * pending events.
 444          * This applies to any hw interrupts that allow a second
 445          * instance of the same irq to arrive while we are in do_IRQ
 446          * or in the handler. But the code here only handles the _second_
 447          * instance of the irq, not the third or fourth. So it is mostly
 448          * useful for irq hardware that does not mask cleanly in an
 449          * SMP environment.
 450          */
 451         for (;;) {
 452                 irqreturn_t action_ret;
 453
 454                 spin_unlock(&desc->lock);
 455
 456                 action_ret = handle_IRQ_event(irq, action);
 457                 if (!noirqdebug)
 458                         note_interrupt(irq, desc, action_ret);
 459
 460                 spin_lock(&desc->lock);
 461                 if (likely(!(desc->status & IRQ_PENDING)))
 462                         break;
 463                 desc->status &= ~IRQ_PENDING;
 464         }
 465         desc->status &= ~IRQ_INPROGRESS;
 466
 467 out:
 468         /*
 469          * The ->end() handler has to deal with interrupts which got
 470          * disabled while the handler was running.
 471          */
 472         desc->chip->end(irq);
 473         spin_unlock(&desc->lock);
 474
 475         return 1;
 476 }
 477 #endif
 478
 479 void early_init_irq_lock_class(void)
 480 {
 481         struct irq_desc *desc;
 482         int i;
 483
 484         for_each_irq_desc(i, desc) {
 485                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 486         }
 487 }
 488
 489 #ifdef CONFIG_SPARSE_IRQ
 490 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 491 {
 492         struct irq_desc *desc = irq_to_desc(irq);
 493         return desc ? desc->kstat_irqs[cpu] : 0;
 494 }
 495 #endif
 496 EXPORT_SYMBOL(kstat_irqs_cpu);
 497