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
  19 #include "internals.h"
  20
  21 /*
  22  * lockdep: we want to handle all irq_desc locks as a single lock-class:
  23  */
  24 static struct lock_class_key irq_desc_lock_class;
  25
  26 /**
  27  * handle_bad_irq - handle spurious and unhandled irqs
  28  * @irq:       the interrupt number
  29  * @desc:      description of the interrupt
  30  *
  31  * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
  32  */
  33 void
  34 handle_bad_irq(unsigned int irq, struct irq_desc *desc)
  35 {
  36         print_irq_desc(irq, desc);
  37 #ifdef CONFIG_HAVE_DYN_ARRAY
  38         kstat_irqs_this_cpu(desc)++;
  39 #else
  40         kstat_irqs_this_cpu(irq)++;
  41 #endif
  42         ack_bad_irq(irq);
  43 }
  44
  45 /*
  46  * Linux has a controller-independent interrupt architecture.
  47  * Every controller has a 'controller-template', that is used
  48  * by the main code to do the right thing. Each driver-visible
  49  * interrupt source is transparently wired to the appropriate
  50  * controller. Thus drivers need not be aware of the
  51  * interrupt-controller.
  52  *
  53  * The code is designed to be easily extended with new/different
  54  * interrupt controllers, without having to do assembly magic or
  55  * having to touch the generic code.
  56  *
  57  * Controller mappings for all interrupt sources:
  58  */
  59 int nr_irqs = NR_IRQS;
  60 EXPORT_SYMBOL_GPL(nr_irqs);
  61
  62 #ifdef CONFIG_HAVE_DYN_ARRAY
  63 static struct irq_desc irq_desc_init = {
  64         .irq = -1U,
  65         .status = IRQ_DISABLED,
  66         .chip = &no_irq_chip,
  67         .handle_irq = handle_bad_irq,
  68         .depth = 1,
  69         .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
  70 #ifdef CONFIG_SMP
  71         .affinity = CPU_MASK_ALL
  72 #endif
  73 };
  74
  75
  76 static void init_one_irq_desc(struct irq_desc *desc)
  77 {
  78         memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
  79         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  80 }
  81
  82 extern int after_bootmem;
  83 extern void *__alloc_bootmem_nopanic(unsigned long size,
  84                              unsigned long align,
  85                              unsigned long goal);
  86
  87 static void init_kstat_irqs(struct irq_desc *desc, int nr_desc, int nr)
  88 {
  89         unsigned long bytes, total_bytes;
  90         char *ptr;
  91         int i;
  92         unsigned long phys;
  93
  94         /* Compute how many bytes we need per irq and allocate them */
  95         bytes = nr * sizeof(unsigned int);
  96         total_bytes = bytes * nr_desc;
  97         if (after_bootmem)
  98                 ptr = kzalloc(total_bytes, GFP_ATOMIC);
  99         else
 100                 ptr = __alloc_bootmem_nopanic(total_bytes, PAGE_SIZE, 0);
 101
 102         if (!ptr)
 103                 panic(" can not allocate kstat_irqs\n");
 104
 105         phys = __pa(ptr);
 106         printk(KERN_DEBUG "kstat_irqs ==> [%#lx - %#lx]\n", phys, phys + total_bytes);
 107
 108         for (i = 0; i < nr_desc; i++) {
 109                 desc[i].kstat_irqs = (unsigned int *)ptr;
 110                 ptr += bytes;
 111         }
 112 }
 113
 114 static void __init init_work(void *data)
 115 {
 116         struct dyn_array *da = data;
 117         int i;
 118         struct  irq_desc *desc;
 119
 120         desc = *da->name;
 121
 122         for (i = 0; i < *da->nr; i++) {
 123                 init_one_irq_desc(&desc[i]);
 124                 desc[i].irq = i;
 125         }
 126
 127         /* init kstat_irqs, nr_cpu_ids is ready already */
 128         init_kstat_irqs(desc, *da->nr, nr_cpu_ids);
 129 }
 130
 131 struct irq_desc *irq_desc;
 132 DEFINE_DYN_ARRAY(irq_desc, sizeof(struct irq_desc), nr_irqs, PAGE_SIZE, init_work);
 133
 134 #else
 135
 136 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 137         [0 ... NR_IRQS-1] = {
 138                 .status = IRQ_DISABLED,
 139                 .chip = &no_irq_chip,
 140                 .handle_irq = handle_bad_irq,
 141                 .depth = 1,
 142                 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
 143 #ifdef CONFIG_SMP
 144                 .affinity = CPU_MASK_ALL
 145 #endif
 146         }
 147 };
 148
 149 #endif
 150
 151 /*
 152  * What should we do if we get a hw irq event on an illegal vector?
 153  * Each architecture has to answer this themself.
 154  */
 155 static void ack_bad(unsigned int irq)
 156 {
 157         struct irq_desc *desc;
 158
 159         desc = irq_to_desc(irq);
 160         print_irq_desc(irq, desc);
 161         ack_bad_irq(irq);
 162 }
 163
 164 /*
 165  * NOP functions
 166  */
 167 static void noop(unsigned int irq)
 168 {
 169 }
 170
 171 static unsigned int noop_ret(unsigned int irq)
 172 {
 173         return 0;
 174 }
 175
 176 /*
 177  * Generic no controller implementation
 178  */
 179 struct irq_chip no_irq_chip = {
 180         .name           = "none",
 181         .startup        = noop_ret,
 182         .shutdown       = noop,
 183         .enable         = noop,
 184         .disable        = noop,
 185         .ack            = ack_bad,
 186         .end            = noop,
 187 };
 188
 189 /*
 190  * Generic dummy implementation which can be used for
 191  * real dumb interrupt sources
 192  */
 193 struct irq_chip dummy_irq_chip = {
 194         .name           = "dummy",
 195         .startup        = noop_ret,
 196         .shutdown       = noop,
 197         .enable         = noop,
 198         .disable        = noop,
 199         .ack            = noop,
 200         .mask           = noop,
 201         .unmask         = noop,
 202         .end            = noop,
 203 };
 204
 205 /*
 206  * Special, empty irq handler:
 207  */
 208 irqreturn_t no_action(int cpl, void *dev_id)
 209 {
 210         return IRQ_NONE;
 211 }
 212
 213 /**
 214  * handle_IRQ_event - irq action chain handler
 215  * @irq:        the interrupt number
 216  * @action:     the interrupt action chain for this irq
 217  *
 218  * Handles the action chain of an irq event
 219  */
 220 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
 221 {
 222         irqreturn_t ret, retval = IRQ_NONE;
 223         unsigned int status = 0;
 224
 225         if (!(action->flags & IRQF_DISABLED))
 226                 local_irq_enable_in_hardirq();
 227
 228         do {
 229                 ret = action->handler(irq, action->dev_id);
 230                 if (ret == IRQ_HANDLED)
 231                         status |= action->flags;
 232                 retval |= ret;
 233                 action = action->next;
 234         } while (action);
 235
 236         if (status & IRQF_SAMPLE_RANDOM)
 237                 add_interrupt_randomness(irq);
 238         local_irq_disable();
 239
 240         return retval;
 241 }
 242
 243 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
 244 /**
 245  * __do_IRQ - original all in one highlevel IRQ handler
 246  * @irq:        the interrupt number
 247  *
 248  * __do_IRQ handles all normal device IRQ's (the special
 249  * SMP cross-CPU interrupts have their own specific
 250  * handlers).
 251  *
 252  * This is the original x86 implementation which is used for every
 253  * interrupt type.
 254  */
 255 unsigned int __do_IRQ(unsigned int irq)
 256 {
 257         struct irq_desc *desc = irq_to_desc(irq);
 258         struct irqaction *action;
 259         unsigned int status;
 260
 261 #ifdef CONFIG_HAVE_DYN_ARRAY
 262         kstat_irqs_this_cpu(desc)++;
 263 #else
 264         kstat_irqs_this_cpu(irq)++;
 265 #endif
 266         if (CHECK_IRQ_PER_CPU(desc->status)) {
 267                 irqreturn_t action_ret;
 268
 269                 /*
 270                  * No locking required for CPU-local interrupts:
 271                  */
 272                 if (desc->chip->ack)
 273                         desc->chip->ack(irq);
 274                 if (likely(!(desc->status & IRQ_DISABLED))) {
 275                         action_ret = handle_IRQ_event(irq, desc->action);
 276                         if (!noirqdebug)
 277                                 note_interrupt(irq, desc, action_ret);
 278                 }
 279                 desc->chip->end(irq);
 280                 return 1;
 281         }
 282
 283         spin_lock(&desc->lock);
 284         if (desc->chip->ack)
 285                 desc->chip->ack(irq);
 286         /*
 287          * REPLAY is when Linux resends an IRQ that was dropped earlier
 288          * WAITING is used by probe to mark irqs that are being tested
 289          */
 290         status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 291         status |= IRQ_PENDING; /* we _want_ to handle it */
 292
 293         /*
 294          * If the IRQ is disabled for whatever reason, we cannot
 295          * use the action we have.
 296          */
 297         action = NULL;
 298         if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
 299                 action = desc->action;
 300                 status &= ~IRQ_PENDING; /* we commit to handling */
 301                 status |= IRQ_INPROGRESS; /* we are handling it */
 302         }
 303         desc->status = status;
 304
 305         /*
 306          * If there is no IRQ handler or it was disabled, exit early.
 307          * Since we set PENDING, if another processor is handling
 308          * a different instance of this same irq, the other processor
 309          * will take care of it.
 310          */
 311         if (unlikely(!action))
 312                 goto out;
 313
 314         /*
 315          * Edge triggered interrupts need to remember
 316          * pending events.
 317          * This applies to any hw interrupts that allow a second
 318          * instance of the same irq to arrive while we are in do_IRQ
 319          * or in the handler. But the code here only handles the _second_
 320          * instance of the irq, not the third or fourth. So it is mostly
 321          * useful for irq hardware that does not mask cleanly in an
 322          * SMP environment.
 323          */
 324         for (;;) {
 325                 irqreturn_t action_ret;
 326
 327                 spin_unlock(&desc->lock);
 328
 329                 action_ret = handle_IRQ_event(irq, action);
 330                 if (!noirqdebug)
 331                         note_interrupt(irq, desc, action_ret);
 332
 333                 spin_lock(&desc->lock);
 334                 if (likely(!(desc->status & IRQ_PENDING)))
 335                         break;
 336                 desc->status &= ~IRQ_PENDING;
 337         }
 338         desc->status &= ~IRQ_INPROGRESS;
 339
 340 out:
 341         /*
 342          * The ->end() handler has to deal with interrupts which got
 343          * disabled while the handler was running.
 344          */
 345         desc->chip->end(irq);
 346         spin_unlock(&desc->lock);
 347
 348         return 1;
 349 }
 350 #endif
 351
 352
 353 #ifdef CONFIG_TRACE_IRQFLAGS
 354 void early_init_irq_lock_class(void)
 355 {
 356 #ifndef CONFIG_HAVE_DYN_ARRAY
 357         int i;
 358
 359         for (i = 0; i < nr_irqs; i++)
 360                 lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 361 #endif
 362 }
 363 #endif
 364
 365 #ifdef CONFIG_HAVE_DYN_ARRAY
 366 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
 367 {
 368         struct irq_desc *desc = irq_to_desc(irq);
 369         return desc->kstat_irqs[cpu];
 370 }
 371 #endif
 372 EXPORT_SYMBOL(kstat_irqs_cpu);
 373