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   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         int node;
  87         void *ptr;
  88
  89         node = cpu_to_node(cpu);
  90         ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node);
  91
  92         /*
  93          * don't overwite if can not get new one
  94          * init_copy_kstat_irqs() could still use old one
  95          */
  96         if (ptr) {
  97                 printk(KERN_DEBUG "  alloc kstat_irqs on cpu %d node %d\n",
  98                          cpu, node);
  99                 desc->kstat_irqs = ptr;
 100         }
 101 }
 102
 103 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
 104 {
 105         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
 106
 107         spin_lock_init(&desc->lock);
 108         desc->irq = irq;
 109 #ifdef CONFIG_SMP
 110         desc->cpu = cpu;
 111 #endif
 112         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 113         init_kstat_irqs(desc, cpu, nr_cpu_ids);
 114         if (!desc->kstat_irqs) {
 115                 printk(KERN_ERR "can not alloc kstat_irqs\n");
 116                 BUG_ON(1);
 117         }
 118         arch_init_chip_data(desc, cpu);
 119 }
 120
 121 /*
 122  * Protect the sparse_irqs:
 123  */
 124 DEFINE_SPINLOCK(sparse_irq_lock);
 125
 126 struct irq_desc *irq_desc_ptrs[NR_IRQS] __read_mostly;
 127
 128 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
 129         [0 ... NR_IRQS_LEGACY-1] = {
 130                 .irq        = -1,
 131                 .status     = IRQ_DISABLED,
 132                 .chip       = &no_irq_chip,
 133                 .handle_irq = handle_bad_irq,
 134                 .depth      = 1,
 135                 .lock       = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
 136 #ifdef CONFIG_SMP
 137                 .affinity   = CPU_MASK_ALL
 138 #endif
 139         }
 140 };
 141
 142 /* FIXME: use bootmem alloc ...*/
 143 static unsigned int kstat_irqs_legacy[NR_IRQS_LEGACY][NR_CPUS];
 144
 145 int __init early_irq_init(void)
 146 {
 147         struct irq_desc *desc;
 148         int legacy_count;
 149         int i;
 150
 151         init_irq_default_affinity();
 152
 153         desc = irq_desc_legacy;
 154         legacy_count = ARRAY_SIZE(irq_desc_legacy);
 155
 156         for (i = 0; i < legacy_count; i++) {
 157                 desc[i].irq = i;
 158                 desc[i].kstat_irqs = kstat_irqs_legacy[i];
 159                 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
 160
 161                 irq_desc_ptrs[i] = desc + i;
 162         }
 163
 164         for (i = legacy_count; i < NR_IRQS; i++)
 165                 irq_desc_ptrs[i] = NULL;
 166
 167         return arch_early_irq_init();
 168 }
 169
 170 struct irq_desc *irq_to_desc(unsigned int irq)
 171 {
 172         return (irq < NR_IRQS) ? irq_desc_ptrs[irq] : NULL;
 173 }
 174
 175 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 176 {
 177         struct irq_desc *desc;
 178         unsigned long flags;
 179         int node;
 180
 181         if (irq >= NR_IRQS) {
 182                 printk(KERN_WARNING "irq >= NR_IRQS in irq_to_desc_alloc: %d %d\n",
 183                                 irq, NR_IRQS);
 184                 WARN_ON(1);
 185                 return NULL;
 186         }
 187
 188         desc = irq_desc_ptrs[irq];
 189         if (desc)
 190                 return desc;
 191
 192         spin_lock_irqsave(&sparse_irq_lock, flags);
 193
 194         /* We have to check it to avoid races with another CPU */
 195         desc = irq_desc_ptrs[irq];
 196         if (desc)
 197                 goto out_unlock;
 198
 199         node = cpu_to_node(cpu);
 200         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
 201         printk(KERN_DEBUG "  alloc irq_desc for %d on cpu %d node %d\n",
 202                  irq, cpu, node);
 203         if (!desc) {
 204                 printk(KERN_ERR "can not alloc irq_desc\n");
 205                 BUG_ON(1);
 206         }
 207         init_one_irq_desc(irq, desc, cpu);
 208
 209         irq_desc_ptrs[irq] = desc;
 210
 211 out_unlock:
 212         spin_unlock_irqrestore(&sparse_irq_lock, flags);
 213
 214         return desc;
 215 }
 216
 217 #else /* !CONFIG_SPARSE_IRQ */
 218
 219 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 220         [0 ... NR_IRQS-1] = {
 221                 .status = IRQ_DISABLED,
 222                 .chip = &no_irq_chip,
 223                 .handle_irq = handle_bad_irq,
 224                 .depth = 1,
 225                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 226 #ifdef CONFIG_SMP
 227                 .affinity = CPU_MASK_ALL
 228 #endif
 229         }
 230 };
 231
 232 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
 233 int __init early_irq_init(void)
 234 {
 235         struct irq_desc *desc;
 236         int count;
 237         int i;
 238
 239         init_irq_default_affinity();
 240
 241         desc = irq_desc;
 242         count = ARRAY_SIZE(irq_desc);
 243
 244         for (i = 0; i < count; i++) {
 245                 desc[i].irq = i;
 246                 desc[i].kstat_irqs = kstat_irqs_all[i];
 247         }
 248
 249         return arch_early_irq_init();
 250 }
 251
 252 struct irq_desc *irq_to_desc(unsigned int irq)
 253 {
 254         return (irq < NR_IRQS) ? irq_desc + irq : NULL;
 255 }
 256
 257 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
 258 {
 259         return irq_to_desc(irq);
 260 }
 261 #endif /* !CONFIG_SPARSE_IRQ */
 262
 263 void clear_kstat_irqs(struct irq_desc *desc)
 264 {
 265         memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
 266 }
 267
 268 /*
 269  * What should we do if we get a hw irq event on an illegal vector?
 270  * Each architecture has to answer this themself.
 271  */
 272 static void ack_bad(unsigned int irq)
 273 {
 274         struct irq_desc *desc = irq_to_desc(irq);
 275
 276         print_irq_desc(irq, desc);
 277         ack_bad_irq(irq);
 278 }
 279
 280 /*
 281  * NOP functions
 282  */
 283 static void noop(unsigned int irq)
 284 {
 285 }
 286
 287 static unsigned int noop_ret(unsigned int irq)
 288 {
 289         return 0;
 290 }
 291
 292 /*
 293  * Generic no controller implementation
 294  */
 295 struct irq_chip no_irq_chip = {
 296         .name           = "none",
 297         .startup        = noop_ret,
 298         .shutdown       = noop,
 299         .enable         = noop,
 300         .disable        = noop,
 301         .ack            = ack_bad,
 302         .end            = noop,
 303 };
 304
 305 /*
 306  * Generic dummy implementation which can be used for
 307  * real dumb interrupt sources
 308  */
 309 struct irq_chip dummy_irq_chip = {
 310         .name           = "dummy",
 311         .startup        = noop_ret,
 312         .shutdown       = noop,
 313         .enable         = noop,
 314         .disable        = noop,
 315         .ack            = noop,
 316         .mask           = noop,
 317         .unmask         = noop,
 318         .end            = noop,
 319 };
 320
 321 /*
 322  * Special, empty irq handler:
 323  */
 324 irqreturn_t no_action(int cpl, void *dev_id)
 325 {
 326         return IRQ_NONE;
 327 }
 328
 329 /**
 330  * handle_IRQ_event - irq action chain handler
 331  * @irq:        the interrupt number
 332  * @action:     the interrupt action chain for this irq
 333  *
 334  * Handles the action chain of an irq event
 335  */
 336 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 337 {
 338         irqreturn_t ret, retval = IRQ_NONE;
 339         unsigned int status = 0;
 340
 341         WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
 342
 343         if (!(action->flags & IRQF_DISABLED))
 344                 local_irq_enable_in_hardirq();
 345
 346         do {
 347                 ret = action->handler(irq, action->dev_id);
 348                 if (ret == IRQ_HANDLED)
 349                         status |= action->flags;
 350                 retval |= ret;
 351                 action = action->next;
 352         } while (action);
 353
 354         if (status & IRQF_SAMPLE_RANDOM)
 355                 add_interrupt_randomness(irq);
 356         local_irq_disable();
 357
 358         return retval;
 359 }
 360
 361 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 362
 363 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
 364 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
 365 #endif
 366
 367 /**
 368  * __do_IRQ - original all in one highlevel IRQ handler
 369  * @irq:        the interrupt number
 370  *
 371  * __do_IRQ handles all normal device IRQ's (the special
 372  * SMP cross-CPU interrupts have their own specific
 373  * handlers).
 374  *
 375  * This is the original x86 implementation which is used for every
 376  * interrupt type.
 377  */
 378 unsigned int __do_IRQ(unsigned int irq)
 379 {
 380         struct irq_desc *desc = irq_to_desc(irq);
 381         struct irqaction *action;
 382         unsigned int status;
 383
 384         kstat_incr_irqs_this_cpu(irq, desc);
 385
 386         if (CHECK_IRQ_PER_CPU(desc->status)) {
 387                 irqreturn_t action_ret;
 388
 389                 /*
 390                  * No locking required for CPU-local interrupts:
 391                  */
 392                 if (desc->chip->ack) {
 393                         desc->chip->ack(irq);
 394                         /* get new one */
 395                         desc = irq_remap_to_desc(irq, desc);
 396                 }
 397                 if (likely(!(desc->status & IRQ_DISABLED))) {
 398                         action_ret = handle_IRQ_event(irq, desc->action);
 399                         if (!noirqdebug)
 400                                 note_interrupt(irq, desc, action_ret);
 401                 }
 402                 desc->chip->end(irq);
 403                 return 1;
 404         }
 405
 406         spin_lock(&desc->lock);
 407         if (desc->chip->ack) {
 408                 desc->chip->ack(irq);
 409                 desc = irq_remap_to_desc(irq, desc);
 410         }
 411         /*
 412          * REPLAY is when Linux resends an IRQ that was dropped earlier
 413          * WAITING is used by probe to mark irqs that are being tested
 414          */
 415         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 416         status |= IRQ_PENDING; /* we _want_ to handle it */
 417
 418         /*
 419          * If the IRQ is disabled for whatever reason, we cannot
 420          * use the action we have.
 421          */
 422         action = NULL;
 423         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 424                 action = desc->action;
 425                 status &= ~IRQ_PENDING; /* we commit to handling */
 426                 status |= IRQ_INPROGRESS; /* we are handling it */
 427         }
 428         desc->status = status;
 429
 430         /*
 431          * If there is no IRQ handler or it was disabled, exit early.
 432          * Since we set PENDING, if another processor is handling
 433          * a different instance of this same irq, the other processor
 434          * will take care of it.
 435          */
 436         if (unlikely(!action))
 437                 goto out;
 438
 439         /*
 440          * Edge triggered interrupts need to remember
 441          * pending events.
 442          * This applies to any hw interrupts that allow a second
 443          * instance of the same irq to arrive while we are in do_IRQ
 444          * or in the handler. But the code here only handles the _second_
 445          * instance of the irq, not the third or fourth. So it is mostly
 446          * useful for irq hardware that does not mask cleanly in an
 447          * SMP environment.
 448          */
 449         for (;;) {
 450                 irqreturn_t action_ret;
 451
 452                 spin_unlock(&desc->lock);
 453
 454                 action_ret = handle_IRQ_event(irq, action);
 455                 if (!noirqdebug)
 456                         note_interrupt(irq, desc, action_ret);
 457
 458                 spin_lock(&desc->lock);
 459                 if (likely(!(desc->status & IRQ_PENDING)))
 460                         break;
 461                 desc->status &= ~IRQ_PENDING;
 462         }
 463         desc->status &= ~IRQ_INPROGRESS;
 464
 465 out:
 466         /*
 467          * The ->end() handler has to deal with interrupts which got
 468          * disabled while the handler was running.
 469          */
 470         desc->chip->end(irq);
 471         spin_unlock(&desc->lock);
 472
 473         return 1;
 474 }
 475 #endif
 476
 477 void early_init_irq_lock_class(void)
 478 {
 479         struct irq_desc *desc;
 480         int i;
 481
 482         for_each_irq_desc(i, desc) {
 483                 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 484         }
 485 }
 486
 487 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 488 {
 489         struct irq_desc *desc = irq_to_desc(irq);
 490         return desc ? desc->kstat_irqs[cpu] : 0;
 491 }
 492 EXPORT_SYMBOL(kstat_irqs_cpu);
 493