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