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 /* FIXME: use bootmem alloc ...*/
 128 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
 129
 130 int __init early_irq_init(void)
 131 {
 132         struct irq_desc *desc;
 133         int legacy_count;
 134         int i;
 135
 136         printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
 137
 138         desc = irq_desc_legacy;
 139         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 140
 141         /* allocate irq_desc_ptrs array based on nr_irqs */
 142         irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
 143
 144         for (i = 0; i < legacy_count; i++) {
 145                 desc[i].irq = i;
 146                 desc[i].kstat_irqs = kstat_irqs_legacy[i];
 147                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 148                 init_alloc_desc_masks(&desc[i], 0, true);
 149                 irq_desc_ptrs[i] = desc + i;
 150         }
 151
 152         for (i = legacy_count; i < nr_irqs; i++)
 153                 irq_desc_ptrs[i] = NULL;
 154
 155         return arch_early_irq_init();
 156 }
 157
 158 struct irq_desc *irq_to_desc(unsigned int irq)
 159 {
 160         if (irq_desc_ptrs && irq < nr_irqs)
 161                 return irq_desc_ptrs[irq];
 162
 163         return NULL;
 164 }
 165
 166 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 167 {
 168         struct irq_desc *desc;
 169         unsigned long flags;
 170         int node;
 171
 172         if (irq >= nr_irqs) {
 173                 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
 174                         irq, nr_irqs);
 175                 return NULL;
 176         }
 177
 178         desc = irq_desc_ptrs[irq];
 179         if (desc)
 180                 return desc;
 181
 182         spin_lock_irqsave(&sparse_irq_lock, flags);
 183
 184         /* We have to check it to avoid races with another CPU */
 185         desc = irq_desc_ptrs[irq];
 186         if (desc)
 187                 goto out_unlock;
 188
 189         node = cpu_to_node(cpu);
 190         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 191         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
 192                  irq, cpu, node);
 193         if (!desc) {
 194                 printk(KERN_ERR "can not alloc irq_desc\n");
 195                 BUG_ON(1);
 196         }
 197         init_one_irq_desc(irq, desc, cpu);
 198
 199         irq_desc_ptrs[irq] = desc;
 200
 201 out_unlock:
 202         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 203
 204         return desc;
 205 }
 206
 207 #else /* !CONFIG_SPARSE_IRQ */
 208
 209 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 210         [0 ... NR_IRQS-1] = {
 211                 .status = IRQ_DISABLED,
 212                 .chip = &no_irq_chip,
 213                 .handle_irq = handle_bad_irq,
 214                 .depth = 1,
 215                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 216         }
 217 };
 218
 219 int __init early_irq_init(void)
 220 {
 221         struct irq_desc *desc;
 222         int count;
 223         int i;
 224
 225         printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
 226
 227         desc = irq_desc;
 228         count = ARRAY_SIZE(irq_desc);
 229
 230         for (i = 0; i < count; i++) {
 231                 desc[i].irq = i;
 232                 init_alloc_desc_masks(&desc[i], 0, true);
 233         }
 234         return arch_early_irq_init();
 235 }
 236
 237 struct irq_desc *irq_to_desc(unsigned int irq)
 238 {
 239         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 240 }
 241
 242 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 243 {
 244         return irq_to_desc(irq);
 245 }
 246 #endif /* !CONFIG_SPARSE_IRQ */
 247
 248 /*
 249  * What should we do if we get a hw irq event on an illegal vector?
 250  * Each architecture has to answer this themself.
 251  */
 252 static void ack_bad(unsigned int irq)
 253 {
 254         struct irq_desc *desc = irq_to_desc(irq);
 255
 256         print_irq_desc(irq, desc);
 257         ack_bad_irq(irq);
 258 }
 259
 260 /*
 261  * NOP functions
 262  */
 263 static void noop(unsigned int irq)
 264 {
 265 }
 266
 267 static unsigned int noop_ret(unsigned int irq)
 268 {
 269         return 0;
 270 }
 271
 272 /*
 273  * Generic no controller implementation
 274  */
 275 struct irq_chip no_irq_chip = {
 276         .name           = "none",
 277         .startup        = noop_ret,
 278         .shutdown       = noop,
 279         .enable         = noop,
 280         .disable        = noop,
 281         .ack            = ack_bad,
 282         .end            = noop,
 283 };
 284
 285 /*
 286  * Generic dummy implementation which can be used for
 287  * real dumb interrupt sources
 288  */
 289 struct irq_chip dummy_irq_chip = {
 290         .name           = "dummy",
 291         .startup        = noop_ret,
 292         .shutdown       = noop,
 293         .enable         = noop,
 294         .disable        = noop,
 295         .ack            = noop,
 296         .mask           = noop,
 297         .unmask         = noop,
 298         .end            = noop,
 299 };
 300
 301 /*
 302  * Special, empty irq handler:
 303  */
 304 irqreturn_t no_action(int cpl, void *dev_id)
 305 {
 306         return IRQ_NONE;
 307 }
 308
 309 /**
 310  * handle_IRQ_event - irq action chain handler
 311  * @irq:        the interrupt number
 312  * @action:     the interrupt action chain for this irq
 313  *
 314  * Handles the action chain of an irq event
 315  */
 316 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 317 {
 318         irqreturn_t ret, retval = IRQ_NONE;
 319         unsigned int status = 0;
 320
 321         if (!(action->flags & IRQF_DISABLED))
 322                 local_irq_enable_in_hardirq();
 323
 324         do {
 325                 ret = action->handler(irq, action->dev_id);
 326                 if (ret == IRQ_HANDLED)
 327                         status |= action->flags;
 328                 retval |= ret;
 329                 action = action->next;
 330         } while (action);
 331
 332         if (status & IRQF_SAMPLE_RANDOM)
 333                 add_interrupt_randomness(irq);
 334         local_irq_disable();
 335
 336         return retval;
 337 }
 338
 339 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 340 /**
 341  * __do_IRQ - original all in one highlevel IRQ handler
 342  * @irq:        the interrupt number
 343  *
 344  * __do_IRQ handles all normal device IRQ's (the special
 345  * SMP cross-CPU interrupts have their own specific
 346  * handlers).
 347  *
 348  * This is the original x86 implementation which is used for every
 349  * interrupt type.
 350  */
 351 unsigned int __do_IRQ(unsigned int irq)
 352 {
 353         struct irq_desc *desc = irq_to_desc(irq);
 354         struct irqaction *action;
 355         unsigned int status;
 356
 357         kstat_incr_irqs_this_cpu(irq, desc);
 358
 359         if (CHECK_IRQ_PER_CPU(desc->status)) {
 360                 irqreturn_t action_ret;
 361
 362                 /*
 363                  * No locking required for CPU-local interrupts:
 364                  */
 365                 if (desc->chip->ack) {
 366                         desc->chip->ack(irq);
 367                         /* get new one */
 368                         desc = irq_remap_to_desc(irq, desc);
 369                 }
 370                 if (likely(!(desc->status & IRQ_DISABLED))) {
 371                         action_ret = handle_IRQ_event(irq, desc->action);
 372                         if (!noirqdebug)
 373                                 note_interrupt(irq, desc, action_ret);
 374                 }
 375                 desc->chip->end(irq);
 376                 return 1;
 377         }
 378
 379         spin_lock(&desc->lock);
 380         if (desc->chip->ack) {
 381                 desc->chip->ack(irq);
 382                 desc = irq_remap_to_desc(irq, desc);
 383         }
 384         /*
 385          * REPLAY is when Linux resends an IRQ that was dropped earlier
 386          * WAITING is used by probe to mark irqs that are being tested
 387          */
 388         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 389         status |= IRQ_PENDING; /* we _want_ to handle it */
 390
 391         /*
 392          * If the IRQ is disabled for whatever reason, we cannot
 393          * use the action we have.
 394          */
 395         action = NULL;
 396         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 397                 action = desc->action;
 398                 status &= ~IRQ_PENDING; /* we commit to handling */
 399                 status |= IRQ_INPROGRESS; /* we are handling it */
 400         }
 401         desc->status = status;
 402
 403         /*
 404          * If there is no IRQ handler or it was disabled, exit early.
 405          * Since we set PENDING, if another processor is handling
 406          * a different instance of this same irq, the other processor
 407          * will take care of it.
 408          */
 409         if (unlikely(!action))
 410                 goto out;
 411
 412         /*
 413          * Edge triggered interrupts need to remember
 414          * pending events.
 415          * This applies to any hw interrupts that allow a second
 416          * instance of the same irq to arrive while we are in do_IRQ
 417          * or in the handler. But the code here only handles the _second_
 418          * instance of the irq, not the third or fourth. So it is mostly
 419          * useful for irq hardware that does not mask cleanly in an
 420          * SMP environment.
 421          */
 422         for (;;) {
 423                 irqreturn_t action_ret;
 424
 425                 spin_unlock(&desc->lock);
 426
 427                 action_ret = handle_IRQ_event(irq, action);
 428                 if (!noirqdebug)
 429                         note_interrupt(irq, desc, action_ret);
 430
 431                 spin_lock(&desc->lock);
 432                 if (likely(!(desc->status & IRQ_PENDING)))
 433                         break;
 434                 desc->status &= ~IRQ_PENDING;
 435         }
 436         desc->status &= ~IRQ_INPROGRESS;
 437
 438 out:
 439         /*
 440          * The ->end() handler has to deal with interrupts which got
 441          * disabled while the handler was running.
 442          */
 443         desc->chip->end(irq);
 444         spin_unlock(&desc->lock);
 445
 446         return 1;
 447 }
 448 #endif
 449
 450 void early_init_irq_lock_class(void)
 451 {
 452         struct irq_desc *desc;
 453         int i;
 454
 455         for_each_irq_desc(i, desc) {
 456                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 457         }
 458 }
 459
 460 #ifdef CONFIG_SPARSE_IRQ
 461 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 462 {
 463         struct irq_desc *desc = irq_to_desc(irq);
 464         return desc ? desc->kstat_irqs[cpu] : 0;
 465 }
 466 #endif
 467 EXPORT_SYMBOL(kstat_irqs_cpu);
 468