2 * linux/kernel/irq/handle.c
4 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
5 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
7 * This file contains the core interrupt handling code.
9 * Detailed information is available in Documentation/DocBook/genericirq
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>
22 #include "internals.h"
25 * lockdep: we want to handle all irq_desc locks as a single lock-class:
27 struct lock_class_key irq_desc_lock_class;
30 * handle_bad_irq - handle spurious and unhandled irqs
31 * @irq: the interrupt number
32 * @desc: description of the interrupt
34 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
36 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
38 print_irq_desc(irq, desc);
39 kstat_incr_irqs_this_cpu(irq, desc);
43 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
44 static void __init init_irq_default_affinity(void)
46 alloc_bootmem_cpumask_var(&irq_default_affinity);
47 cpumask_setall(irq_default_affinity);
50 static void __init init_irq_default_affinity(void)
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.
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.
67 * Controller mappings for all interrupt sources:
69 int nr_irqs = NR_IRQS;
70 EXPORT_SYMBOL_GPL(nr_irqs);
72 #ifdef CONFIG_SPARSE_IRQ
74 static struct irq_desc irq_desc_init = {
76 .status = IRQ_DISABLED,
78 .handle_irq = handle_bad_irq,
80 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
83 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
88 node = cpu_to_node(cpu);
89 ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node);
92 * don't overwite if can not get new one
93 * init_copy_kstat_irqs() could still use old one
96 printk(KERN_DEBUG " alloc kstat_irqs on cpu %d node %d\n",
98 desc->kstat_irqs = ptr;
102 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
104 memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
106 spin_lock_init(&desc->lock);
111 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
112 init_kstat_irqs(desc, cpu, nr_cpu_ids);
113 if (!desc->kstat_irqs) {
114 printk(KERN_ERR "can not alloc kstat_irqs\n");
117 if (!init_alloc_desc_masks(desc, cpu, false)) {
118 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
121 arch_init_chip_data(desc, cpu);
125 * Protect the sparse_irqs:
127 DEFINE_SPINLOCK(sparse_irq_lock);
129 struct irq_desc **irq_desc_ptrs __read_mostly;
131 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
132 [0 ... NR_IRQS_LEGACY-1] = {
134 .status = IRQ_DISABLED,
135 .chip = &no_irq_chip,
136 .handle_irq = handle_bad_irq,
138 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
142 static unsigned int *kstat_irqs_legacy;
144 int __init early_irq_init(void)
146 struct irq_desc *desc;
150 init_irq_default_affinity();
152 /* initialize nr_irqs based on nr_cpu_ids */
153 arch_probe_nr_irqs();
154 printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
156 desc = irq_desc_legacy;
157 legacy_count = ARRAY_SIZE(irq_desc_legacy);
159 /* allocate irq_desc_ptrs array based on nr_irqs */
160 irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
162 /* allocate based on nr_cpu_ids */
163 /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
164 kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
167 for (i = 0; i < legacy_count; i++) {
169 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
170 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
171 init_alloc_desc_masks(&desc[i], 0, true);
172 irq_desc_ptrs[i] = desc + i;
175 for (i = legacy_count; i < nr_irqs; i++)
176 irq_desc_ptrs[i] = NULL;
178 return arch_early_irq_init();
181 struct irq_desc *irq_to_desc(unsigned int irq)
183 if (irq_desc_ptrs && irq < nr_irqs)
184 return irq_desc_ptrs[irq];
189 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
191 struct irq_desc *desc;
195 if (irq >= nr_irqs) {
196 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
201 desc = irq_desc_ptrs[irq];
205 spin_lock_irqsave(&sparse_irq_lock, flags);
207 /* We have to check it to avoid races with another CPU */
208 desc = irq_desc_ptrs[irq];
212 node = cpu_to_node(cpu);
213 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
214 printk(KERN_DEBUG " alloc irq_desc for %d on cpu %d node %d\n",
217 printk(KERN_ERR "can not alloc irq_desc\n");
220 init_one_irq_desc(irq, desc, cpu);
222 irq_desc_ptrs[irq] = desc;
225 spin_unlock_irqrestore(&sparse_irq_lock, flags);
230 #else /* !CONFIG_SPARSE_IRQ */
232 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
233 [0 ... NR_IRQS-1] = {
234 .status = IRQ_DISABLED,
235 .chip = &no_irq_chip,
236 .handle_irq = handle_bad_irq,
238 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
242 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
243 int __init early_irq_init(void)
245 struct irq_desc *desc;
249 init_irq_default_affinity();
251 printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
254 count = ARRAY_SIZE(irq_desc);
256 for (i = 0; i < count; i++) {
258 init_alloc_desc_masks(&desc[i], 0, true);
259 desc[i].kstat_irqs = kstat_irqs_all[i];
261 return arch_early_irq_init();
264 struct irq_desc *irq_to_desc(unsigned int irq)
266 return (irq < NR_IRQS) ? irq_desc + irq : NULL;
269 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
271 return irq_to_desc(irq);
273 #endif /* !CONFIG_SPARSE_IRQ */
275 void clear_kstat_irqs(struct irq_desc *desc)
277 memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
281 * What should we do if we get a hw irq event on an illegal vector?
282 * Each architecture has to answer this themself.
284 static void ack_bad(unsigned int irq)
286 struct irq_desc *desc = irq_to_desc(irq);
288 print_irq_desc(irq, desc);
295 static void noop(unsigned int irq)
299 static unsigned int noop_ret(unsigned int irq)
305 * Generic no controller implementation
307 struct irq_chip no_irq_chip = {
318 * Generic dummy implementation which can be used for
319 * real dumb interrupt sources
321 struct irq_chip dummy_irq_chip = {
334 * Special, empty irq handler:
336 irqreturn_t no_action(int cpl, void *dev_id)
341 static void warn_no_thread(unsigned int irq, struct irqaction *action)
343 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
346 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
347 "but no thread function available.", irq, action->name);
351 * handle_IRQ_event - irq action chain handler
352 * @irq: the interrupt number
353 * @action: the interrupt action chain for this irq
355 * Handles the action chain of an irq event
357 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
359 irqreturn_t ret, retval = IRQ_NONE;
360 unsigned int status = 0;
362 WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
364 if (!(action->flags & IRQF_DISABLED))
365 local_irq_enable_in_hardirq();
368 ret = action->handler(irq, action->dev_id);
371 case IRQ_WAKE_THREAD:
373 * Set result to handled so the spurious check
379 * Catch drivers which return WAKE_THREAD but
380 * did not set up a thread function
382 if (unlikely(!action->thread_fn)) {
383 warn_no_thread(irq, action);
388 * Wake up the handler thread for this
389 * action. In case the thread crashed and was
390 * killed we just pretend that we handled the
391 * interrupt. The hardirq handler above has
392 * disabled the device interrupt, so no irq
395 if (likely(!test_bit(IRQTF_DIED,
396 &action->thread_flags))) {
397 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
398 wake_up_process(action->thread);
401 /* Fall through to add to randomness */
403 status |= action->flags;
411 action = action->next;
414 if (status & IRQF_SAMPLE_RANDOM)
415 add_interrupt_randomness(irq);
421 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
423 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
424 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
428 * __do_IRQ - original all in one highlevel IRQ handler
429 * @irq: the interrupt number
431 * __do_IRQ handles all normal device IRQ's (the special
432 * SMP cross-CPU interrupts have their own specific
435 * This is the original x86 implementation which is used for every
438 unsigned int __do_IRQ(unsigned int irq)
440 struct irq_desc *desc = irq_to_desc(irq);
441 struct irqaction *action;
444 kstat_incr_irqs_this_cpu(irq, desc);
446 if (CHECK_IRQ_PER_CPU(desc->status)) {
447 irqreturn_t action_ret;
450 * No locking required for CPU-local interrupts:
452 if (desc->chip->ack) {
453 desc->chip->ack(irq);
455 desc = irq_remap_to_desc(irq, desc);
457 if (likely(!(desc->status & IRQ_DISABLED))) {
458 action_ret = handle_IRQ_event(irq, desc->action);
460 note_interrupt(irq, desc, action_ret);
462 desc->chip->end(irq);
466 spin_lock(&desc->lock);
467 if (desc->chip->ack) {
468 desc->chip->ack(irq);
469 desc = irq_remap_to_desc(irq, desc);
472 * REPLAY is when Linux resends an IRQ that was dropped earlier
473 * WAITING is used by probe to mark irqs that are being tested
475 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
476 status |= IRQ_PENDING; /* we _want_ to handle it */
479 * If the IRQ is disabled for whatever reason, we cannot
480 * use the action we have.
483 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
484 action = desc->action;
485 status &= ~IRQ_PENDING; /* we commit to handling */
486 status |= IRQ_INPROGRESS; /* we are handling it */
488 desc->status = status;
491 * If there is no IRQ handler or it was disabled, exit early.
492 * Since we set PENDING, if another processor is handling
493 * a different instance of this same irq, the other processor
494 * will take care of it.
496 if (unlikely(!action))
500 * Edge triggered interrupts need to remember
502 * This applies to any hw interrupts that allow a second
503 * instance of the same irq to arrive while we are in do_IRQ
504 * or in the handler. But the code here only handles the _second_
505 * instance of the irq, not the third or fourth. So it is mostly
506 * useful for irq hardware that does not mask cleanly in an
510 irqreturn_t action_ret;
512 spin_unlock(&desc->lock);
514 action_ret = handle_IRQ_event(irq, action);
516 note_interrupt(irq, desc, action_ret);
518 spin_lock(&desc->lock);
519 if (likely(!(desc->status & IRQ_PENDING)))
521 desc->status &= ~IRQ_PENDING;
523 desc->status &= ~IRQ_INPROGRESS;
527 * The ->end() handler has to deal with interrupts which got
528 * disabled while the handler was running.
530 desc->chip->end(irq);
531 spin_unlock(&desc->lock);
537 void early_init_irq_lock_class(void)
539 struct irq_desc *desc;
542 for_each_irq_desc(i, desc) {
543 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
547 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
549 struct irq_desc *desc = irq_to_desc(irq);
550 return desc ? desc->kstat_irqs[cpu] : 0;
552 EXPORT_SYMBOL(kstat_irqs_cpu);