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 #define CREATE_TRACE_POINTS
23 #include <trace/events/irq.h>
25 #include "internals.h"
28 * lockdep: we want to handle all irq_desc locks as a single lock-class:
30 struct lock_class_key irq_desc_lock_class;
33 * handle_bad_irq - handle spurious and unhandled irqs
34 * @irq: the interrupt number
35 * @desc: description of the interrupt
37 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
39 void handle_bad_irq(unsigned int irq, struct irq_desc *desc)
41 print_irq_desc(irq, desc);
42 kstat_incr_irqs_this_cpu(irq, desc);
46 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
47 static void __init init_irq_default_affinity(void)
49 alloc_bootmem_cpumask_var(&irq_default_affinity);
50 cpumask_setall(irq_default_affinity);
53 static void __init init_irq_default_affinity(void)
59 * Linux has a controller-independent interrupt architecture.
60 * Every controller has a 'controller-template', that is used
61 * by the main code to do the right thing. Each driver-visible
62 * interrupt source is transparently wired to the appropriate
63 * controller. Thus drivers need not be aware of the
64 * interrupt-controller.
66 * The code is designed to be easily extended with new/different
67 * interrupt controllers, without having to do assembly magic or
68 * having to touch the generic code.
70 * Controller mappings for all interrupt sources:
72 int nr_irqs = NR_IRQS;
73 EXPORT_SYMBOL_GPL(nr_irqs);
75 #ifdef CONFIG_SPARSE_IRQ
77 static struct irq_desc irq_desc_init = {
79 .status = IRQ_DISABLED,
81 .handle_irq = handle_bad_irq,
83 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
86 void init_kstat_irqs(struct irq_desc *desc, int cpu, int nr)
91 node = cpu_to_node(cpu);
92 ptr = kzalloc_node(nr * sizeof(*desc->kstat_irqs), GFP_ATOMIC, node);
95 * don't overwite if can not get new one
96 * init_copy_kstat_irqs() could still use old one
99 printk(KERN_DEBUG " alloc kstat_irqs on cpu %d node %d\n",
101 desc->kstat_irqs = ptr;
105 static void init_one_irq_desc(int irq, struct irq_desc *desc, int cpu)
107 memcpy(desc, &irq_desc_init, sizeof(struct irq_desc));
109 spin_lock_init(&desc->lock);
114 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
115 init_kstat_irqs(desc, cpu, nr_cpu_ids);
116 if (!desc->kstat_irqs) {
117 printk(KERN_ERR "can not alloc kstat_irqs\n");
120 if (!init_alloc_desc_masks(desc, cpu, false)) {
121 printk(KERN_ERR "can not alloc irq_desc cpumasks\n");
124 arch_init_chip_data(desc, cpu);
128 * Protect the sparse_irqs:
130 DEFINE_SPINLOCK(sparse_irq_lock);
132 struct irq_desc **irq_desc_ptrs __read_mostly;
134 static struct irq_desc irq_desc_legacy[NR_IRQS_LEGACY] __cacheline_aligned_in_smp = {
135 [0 ... NR_IRQS_LEGACY-1] = {
137 .status = IRQ_DISABLED,
138 .chip = &no_irq_chip,
139 .handle_irq = handle_bad_irq,
141 .lock = __SPIN_LOCK_UNLOCKED(irq_desc_init.lock),
145 static unsigned int *kstat_irqs_legacy;
147 int __init early_irq_init(void)
149 struct irq_desc *desc;
153 init_irq_default_affinity();
155 /* initialize nr_irqs based on nr_cpu_ids */
156 arch_probe_nr_irqs();
157 printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d\n", NR_IRQS, nr_irqs);
159 desc = irq_desc_legacy;
160 legacy_count = ARRAY_SIZE(irq_desc_legacy);
162 /* allocate irq_desc_ptrs array based on nr_irqs */
163 irq_desc_ptrs = alloc_bootmem(nr_irqs * sizeof(void *));
165 /* allocate based on nr_cpu_ids */
166 /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
167 kstat_irqs_legacy = alloc_bootmem(NR_IRQS_LEGACY * nr_cpu_ids *
170 for (i = 0; i < legacy_count; i++) {
172 desc[i].kstat_irqs = kstat_irqs_legacy + i * nr_cpu_ids;
173 lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
174 init_alloc_desc_masks(&desc[i], 0, true);
175 irq_desc_ptrs[i] = desc + i;
178 for (i = legacy_count; i < nr_irqs; i++)
179 irq_desc_ptrs[i] = NULL;
181 return arch_early_irq_init();
184 struct irq_desc *irq_to_desc(unsigned int irq)
186 if (irq_desc_ptrs && irq < nr_irqs)
187 return irq_desc_ptrs[irq];
192 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
194 struct irq_desc *desc;
198 if (irq >= nr_irqs) {
199 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
204 desc = irq_desc_ptrs[irq];
208 spin_lock_irqsave(&sparse_irq_lock, flags);
210 /* We have to check it to avoid races with another CPU */
211 desc = irq_desc_ptrs[irq];
215 node = cpu_to_node(cpu);
216 desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
217 printk(KERN_DEBUG " alloc irq_desc for %d on cpu %d node %d\n",
220 printk(KERN_ERR "can not alloc irq_desc\n");
223 init_one_irq_desc(irq, desc, cpu);
225 irq_desc_ptrs[irq] = desc;
228 spin_unlock_irqrestore(&sparse_irq_lock, flags);
233 #else /* !CONFIG_SPARSE_IRQ */
235 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
236 [0 ... NR_IRQS-1] = {
237 .status = IRQ_DISABLED,
238 .chip = &no_irq_chip,
239 .handle_irq = handle_bad_irq,
241 .lock = __SPIN_LOCK_UNLOCKED(irq_desc->lock),
245 static unsigned int kstat_irqs_all[NR_IRQS][NR_CPUS];
246 int __init early_irq_init(void)
248 struct irq_desc *desc;
252 init_irq_default_affinity();
254 printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);
257 count = ARRAY_SIZE(irq_desc);
259 for (i = 0; i < count; i++) {
261 init_alloc_desc_masks(&desc[i], 0, true);
262 desc[i].kstat_irqs = kstat_irqs_all[i];
264 return arch_early_irq_init();
267 struct irq_desc *irq_to_desc(unsigned int irq)
269 return (irq < NR_IRQS) ? irq_desc + irq : NULL;
272 struct irq_desc *irq_to_desc_alloc_cpu(unsigned int irq, int cpu)
274 return irq_to_desc(irq);
276 #endif /* !CONFIG_SPARSE_IRQ */
278 void clear_kstat_irqs(struct irq_desc *desc)
280 memset(desc->kstat_irqs, 0, nr_cpu_ids * sizeof(*(desc->kstat_irqs)));
284 * What should we do if we get a hw irq event on an illegal vector?
285 * Each architecture has to answer this themself.
287 static void ack_bad(unsigned int irq)
289 struct irq_desc *desc = irq_to_desc(irq);
291 print_irq_desc(irq, desc);
298 static void noop(unsigned int irq)
302 static unsigned int noop_ret(unsigned int irq)
308 * Generic no controller implementation
310 struct irq_chip no_irq_chip = {
321 * Generic dummy implementation which can be used for
322 * real dumb interrupt sources
324 struct irq_chip dummy_irq_chip = {
337 * Special, empty irq handler:
339 irqreturn_t no_action(int cpl, void *dev_id)
344 static void warn_no_thread(unsigned int irq, struct irqaction *action)
346 if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags))
349 printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD "
350 "but no thread function available.", irq, action->name);
354 * handle_IRQ_event - irq action chain handler
355 * @irq: the interrupt number
356 * @action: the interrupt action chain for this irq
358 * Handles the action chain of an irq event
360 irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action)
362 irqreturn_t ret, retval = IRQ_NONE;
363 unsigned int status = 0;
365 WARN_ONCE(!in_irq(), "BUG: IRQ handler called from non-hardirq context!");
367 if (!(action->flags & IRQF_DISABLED))
368 local_irq_enable_in_hardirq();
371 trace_irq_handler_entry(irq, action);
372 ret = action->handler(irq, action->dev_id);
373 trace_irq_handler_exit(irq, action, ret);
376 case IRQ_WAKE_THREAD:
378 * Set result to handled so the spurious check
384 * Catch drivers which return WAKE_THREAD but
385 * did not set up a thread function
387 if (unlikely(!action->thread_fn)) {
388 warn_no_thread(irq, action);
393 * Wake up the handler thread for this
394 * action. In case the thread crashed and was
395 * killed we just pretend that we handled the
396 * interrupt. The hardirq handler above has
397 * disabled the device interrupt, so no irq
400 if (likely(!test_bit(IRQTF_DIED,
401 &action->thread_flags))) {
402 set_bit(IRQTF_RUNTHREAD, &action->thread_flags);
403 wake_up_process(action->thread);
406 /* Fall through to add to randomness */
408 status |= action->flags;
416 action = action->next;
419 if (status & IRQF_SAMPLE_RANDOM)
420 add_interrupt_randomness(irq);
426 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
428 #ifdef CONFIG_ENABLE_WARN_DEPRECATED
429 # warning __do_IRQ is deprecated. Please convert to proper flow handlers
433 * __do_IRQ - original all in one highlevel IRQ handler
434 * @irq: the interrupt number
436 * __do_IRQ handles all normal device IRQ's (the special
437 * SMP cross-CPU interrupts have their own specific
440 * This is the original x86 implementation which is used for every
443 unsigned int __do_IRQ(unsigned int irq)
445 struct irq_desc *desc = irq_to_desc(irq);
446 struct irqaction *action;
449 kstat_incr_irqs_this_cpu(irq, desc);
451 if (CHECK_IRQ_PER_CPU(desc->status)) {
452 irqreturn_t action_ret;
455 * No locking required for CPU-local interrupts:
457 if (desc->chip->ack) {
458 desc->chip->ack(irq);
460 desc = irq_remap_to_desc(irq, desc);
462 if (likely(!(desc->status & IRQ_DISABLED))) {
463 action_ret = handle_IRQ_event(irq, desc->action);
465 note_interrupt(irq, desc, action_ret);
467 desc->chip->end(irq);
471 spin_lock(&desc->lock);
472 if (desc->chip->ack) {
473 desc->chip->ack(irq);
474 desc = irq_remap_to_desc(irq, desc);
477 * REPLAY is when Linux resends an IRQ that was dropped earlier
478 * WAITING is used by probe to mark irqs that are being tested
480 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
481 status |= IRQ_PENDING; /* we _want_ to handle it */
484 * If the IRQ is disabled for whatever reason, we cannot
485 * use the action we have.
488 if (likely(!(status & (IRQ_DISABLED | IRQ_INPROGRESS)))) {
489 action = desc->action;
490 status &= ~IRQ_PENDING; /* we commit to handling */
491 status |= IRQ_INPROGRESS; /* we are handling it */
493 desc->status = status;
496 * If there is no IRQ handler or it was disabled, exit early.
497 * Since we set PENDING, if another processor is handling
498 * a different instance of this same irq, the other processor
499 * will take care of it.
501 if (unlikely(!action))
505 * Edge triggered interrupts need to remember
507 * This applies to any hw interrupts that allow a second
508 * instance of the same irq to arrive while we are in do_IRQ
509 * or in the handler. But the code here only handles the _second_
510 * instance of the irq, not the third or fourth. So it is mostly
511 * useful for irq hardware that does not mask cleanly in an
515 irqreturn_t action_ret;
517 spin_unlock(&desc->lock);
519 action_ret = handle_IRQ_event(irq, action);
521 note_interrupt(irq, desc, action_ret);
523 spin_lock(&desc->lock);
524 if (likely(!(desc->status & IRQ_PENDING)))
526 desc->status &= ~IRQ_PENDING;
528 desc->status &= ~IRQ_INPROGRESS;
532 * The ->end() handler has to deal with interrupts which got
533 * disabled while the handler was running.
535 desc->chip->end(irq);
536 spin_unlock(&desc->lock);
542 void early_init_irq_lock_class(void)
544 struct irq_desc *desc;
547 for_each_irq_desc(i, desc) {
548 lockdep_set_class(&desc->lock, &irq_desc_lock_class);
552 unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
554 struct irq_desc *desc = irq_to_desc(irq);
555 return desc ? desc->kstat_irqs[cpu] : 0;
557 EXPORT_SYMBOL(kstat_irqs_cpu);