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