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