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 <trace/irq.h>
21 #include <linux/bootmem.h>
23 #include "internals.h"
26 * lockdep: we want to handle all irq_desc locks as a single lock-class:
28 struct lock_class_key irq_desc_lock_class
;
31 * handle_bad_irq - handle spurious and unhandled irqs
32 * @irq: the interrupt number
33 * @desc: description of the interrupt
35 * Handles spurious and unhandled IRQ's. It also prints a debugmessage.
37 void handle_bad_irq(unsigned int irq
, struct irq_desc
*desc
)
39 print_irq_desc(irq
, desc
);
40 kstat_incr_irqs_this_cpu(irq
, desc
);
44 #if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_HARDIRQS)
45 static void __init
init_irq_default_affinity(void)
47 alloc_bootmem_cpumask_var(&irq_default_affinity
);
48 cpumask_setall(irq_default_affinity
);
51 static void __init
init_irq_default_affinity(void)
57 * Linux has a controller-independent interrupt architecture.
58 * Every controller has a 'controller-template', that is used
59 * by the main code to do the right thing. Each driver-visible
60 * interrupt source is transparently wired to the appropriate
61 * controller. Thus drivers need not be aware of the
62 * interrupt-controller.
64 * The code is designed to be easily extended with new/different
65 * interrupt controllers, without having to do assembly magic or
66 * having to touch the generic code.
68 * Controller mappings for all interrupt sources:
70 int nr_irqs
= NR_IRQS
;
71 EXPORT_SYMBOL_GPL(nr_irqs
);
73 #ifdef CONFIG_SPARSE_IRQ
75 static struct irq_desc irq_desc_init
= {
77 .status
= IRQ_DISABLED
,
79 .handle_irq
= handle_bad_irq
,
81 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
84 void init_kstat_irqs(struct irq_desc
*desc
, int cpu
, int nr
)
90 /* Compute how many bytes we need per irq and allocate them */
91 bytes
= nr
* sizeof(unsigned int);
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
);
98 desc
->kstat_irqs
= (unsigned int *)ptr
;
101 static void init_one_irq_desc(int irq
, struct irq_desc
*desc
, int cpu
)
103 memcpy(desc
, &irq_desc_init
, sizeof(struct irq_desc
));
105 spin_lock_init(&desc
->lock
);
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");
116 if (!init_alloc_desc_masks(desc
, cpu
, false)) {
117 printk(KERN_ERR
"can not alloc irq_desc cpumasks\n");
120 arch_init_chip_data(desc
, cpu
);
124 * Protect the sparse_irqs:
126 DEFINE_SPINLOCK(sparse_irq_lock
);
128 struct irq_desc
**irq_desc_ptrs __read_mostly
;
130 static struct irq_desc irq_desc_legacy
[NR_IRQS_LEGACY
] __cacheline_aligned_in_smp
= {
131 [0 ... NR_IRQS_LEGACY
-1] = {
133 .status
= IRQ_DISABLED
,
134 .chip
= &no_irq_chip
,
135 .handle_irq
= handle_bad_irq
,
137 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc_init
.lock
),
141 static unsigned int *kstat_irqs_legacy
;
143 int __init
early_irq_init(void)
145 struct irq_desc
*desc
;
149 init_irq_default_affinity();
151 /* initialize nr_irqs based on nr_cpu_ids */
152 arch_probe_nr_irqs();
153 printk(KERN_INFO
"NR_IRQS:%d nr_irqs:%d\n", NR_IRQS
, nr_irqs
);
155 desc
= irq_desc_legacy
;
156 legacy_count
= ARRAY_SIZE(irq_desc_legacy
);
158 /* allocate irq_desc_ptrs array based on nr_irqs */
159 irq_desc_ptrs
= alloc_bootmem(nr_irqs
* sizeof(void *));
161 /* allocate based on nr_cpu_ids */
162 /* FIXME: invert kstat_irgs, and it'd be a per_cpu_alloc'd thing */
163 kstat_irqs_legacy
= alloc_bootmem(NR_IRQS_LEGACY
* nr_cpu_ids
*
166 for (i
= 0; i
< legacy_count
; i
++) {
168 desc
[i
].kstat_irqs
= kstat_irqs_legacy
+ i
* nr_cpu_ids
;
169 lockdep_set_class(&desc
[i
].lock
, &irq_desc_lock_class
);
170 init_alloc_desc_masks(&desc
[i
], 0, true);
171 irq_desc_ptrs
[i
] = desc
+ i
;
174 for (i
= legacy_count
; i
< nr_irqs
; i
++)
175 irq_desc_ptrs
[i
] = NULL
;
177 return arch_early_irq_init();
180 struct irq_desc
*irq_to_desc(unsigned int irq
)
182 if (irq_desc_ptrs
&& irq
< nr_irqs
)
183 return irq_desc_ptrs
[irq
];
188 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
190 struct irq_desc
*desc
;
194 if (irq
>= nr_irqs
) {
195 WARN(1, "irq (%d) >= nr_irqs (%d) in irq_to_desc_alloc\n",
200 desc
= irq_desc_ptrs
[irq
];
204 spin_lock_irqsave(&sparse_irq_lock
, flags
);
206 /* We have to check it to avoid races with another CPU */
207 desc
= irq_desc_ptrs
[irq
];
211 node
= cpu_to_node(cpu
);
212 desc
= kzalloc_node(sizeof(*desc
), GFP_ATOMIC
, node
);
213 printk(KERN_DEBUG
" alloc irq_desc for %d on cpu %d node %d\n",
216 printk(KERN_ERR
"can not alloc irq_desc\n");
219 init_one_irq_desc(irq
, desc
, cpu
);
221 irq_desc_ptrs
[irq
] = desc
;
224 spin_unlock_irqrestore(&sparse_irq_lock
, flags
);
229 #else /* !CONFIG_SPARSE_IRQ */
231 struct irq_desc irq_desc
[NR_IRQS
] __cacheline_aligned_in_smp
= {
232 [0 ... NR_IRQS
-1] = {
233 .status
= IRQ_DISABLED
,
234 .chip
= &no_irq_chip
,
235 .handle_irq
= handle_bad_irq
,
237 .lock
= __SPIN_LOCK_UNLOCKED(irq_desc
->lock
),
241 int __init
early_irq_init(void)
243 struct irq_desc
*desc
;
247 init_irq_default_affinity();
249 printk(KERN_INFO
"NR_IRQS:%d\n", NR_IRQS
);
252 count
= ARRAY_SIZE(irq_desc
);
254 for (i
= 0; i
< count
; i
++) {
256 init_alloc_desc_masks(&desc
[i
], 0, true);
258 return arch_early_irq_init();
261 struct irq_desc
*irq_to_desc(unsigned int irq
)
263 return (irq
< NR_IRQS
) ? irq_desc
+ irq
: NULL
;
266 struct irq_desc
*irq_to_desc_alloc_cpu(unsigned int irq
, int cpu
)
268 return irq_to_desc(irq
);
270 #endif /* !CONFIG_SPARSE_IRQ */
273 * What should we do if we get a hw irq event on an illegal vector?
274 * Each architecture has to answer this themself.
276 static void ack_bad(unsigned int irq
)
278 struct irq_desc
*desc
= irq_to_desc(irq
);
280 print_irq_desc(irq
, desc
);
287 static void noop(unsigned int irq
)
291 static unsigned int noop_ret(unsigned int irq
)
297 * Generic no controller implementation
299 struct irq_chip no_irq_chip
= {
310 * Generic dummy implementation which can be used for
311 * real dumb interrupt sources
313 struct irq_chip dummy_irq_chip
= {
326 * Special, empty irq handler:
328 irqreturn_t
no_action(int cpl
, void *dev_id
)
333 DEFINE_TRACE(irq_handler_entry
);
334 DEFINE_TRACE(irq_handler_exit
);
337 * handle_IRQ_event - irq action chain handler
338 * @irq: the interrupt number
339 * @action: the interrupt action chain for this irq
341 * Handles the action chain of an irq event
343 irqreturn_t
handle_IRQ_event(unsigned int irq
, struct irqaction
*action
)
345 irqreturn_t ret
, retval
= IRQ_NONE
;
346 unsigned int status
= 0;
348 if (!(action
->flags
& IRQF_DISABLED
))
349 local_irq_enable_in_hardirq();
352 trace_irq_handler_entry(irq
, action
);
353 ret
= action
->handler(irq
, action
->dev_id
);
354 trace_irq_handler_exit(irq
, action
, ret
);
355 if (ret
== IRQ_HANDLED
)
356 status
|= action
->flags
;
358 action
= action
->next
;
361 if (status
& IRQF_SAMPLE_RANDOM
)
362 add_interrupt_randomness(irq
);
368 #ifndef CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ
370 * __do_IRQ - original all in one highlevel IRQ handler
371 * @irq: the interrupt number
373 * __do_IRQ handles all normal device IRQ's (the special
374 * SMP cross-CPU interrupts have their own specific
377 * This is the original x86 implementation which is used for every
380 unsigned int __do_IRQ(unsigned int irq
)
382 struct irq_desc
*desc
= irq_to_desc(irq
);
383 struct irqaction
*action
;
386 kstat_incr_irqs_this_cpu(irq
, desc
);
388 if (CHECK_IRQ_PER_CPU(desc
->status
)) {
389 irqreturn_t action_ret
;
392 * No locking required for CPU-local interrupts:
394 if (desc
->chip
->ack
) {
395 desc
->chip
->ack(irq
);
397 desc
= irq_remap_to_desc(irq
, desc
);
399 if (likely(!(desc
->status
& IRQ_DISABLED
))) {
400 action_ret
= handle_IRQ_event(irq
, desc
->action
);
402 note_interrupt(irq
, desc
, action_ret
);
404 desc
->chip
->end(irq
);
408 spin_lock(&desc
->lock
);
409 if (desc
->chip
->ack
) {
410 desc
->chip
->ack(irq
);
411 desc
= irq_remap_to_desc(irq
, desc
);
414 * REPLAY is when Linux resends an IRQ that was dropped earlier
415 * WAITING is used by probe to mark irqs that are being tested
417 status
= desc
->status
& ~(IRQ_REPLAY
| IRQ_WAITING
);
418 status
|= IRQ_PENDING
; /* we _want_ to handle it */
421 * If the IRQ is disabled for whatever reason, we cannot
422 * use the action we have.
425 if (likely(!(status
& (IRQ_DISABLED
| IRQ_INPROGRESS
)))) {
426 action
= desc
->action
;
427 status
&= ~IRQ_PENDING
; /* we commit to handling */
428 status
|= IRQ_INPROGRESS
; /* we are handling it */
430 desc
->status
= status
;
433 * If there is no IRQ handler or it was disabled, exit early.
434 * Since we set PENDING, if another processor is handling
435 * a different instance of this same irq, the other processor
436 * will take care of it.
438 if (unlikely(!action
))
442 * Edge triggered interrupts need to remember
444 * This applies to any hw interrupts that allow a second
445 * instance of the same irq to arrive while we are in do_IRQ
446 * or in the handler. But the code here only handles the _second_
447 * instance of the irq, not the third or fourth. So it is mostly
448 * useful for irq hardware that does not mask cleanly in an
452 irqreturn_t action_ret
;
454 spin_unlock(&desc
->lock
);
456 action_ret
= handle_IRQ_event(irq
, action
);
458 note_interrupt(irq
, desc
, action_ret
);
460 spin_lock(&desc
->lock
);
461 if (likely(!(desc
->status
& IRQ_PENDING
)))
463 desc
->status
&= ~IRQ_PENDING
;
465 desc
->status
&= ~IRQ_INPROGRESS
;
469 * The ->end() handler has to deal with interrupts which got
470 * disabled while the handler was running.
472 desc
->chip
->end(irq
);
473 spin_unlock(&desc
->lock
);
479 void early_init_irq_lock_class(void)
481 struct irq_desc
*desc
;
484 for_each_irq_desc(i
, desc
) {
485 lockdep_set_class(&desc
->lock
, &irq_desc_lock_class
);
489 #ifdef CONFIG_SPARSE_IRQ
490 unsigned int kstat_irqs_cpu(unsigned int irq
, int cpu
)
492 struct irq_desc
*desc
= irq_to_desc(irq
);
493 return desc
? desc
->kstat_irqs
[cpu
] : 0;
496 EXPORT_SYMBOL(kstat_irqs_cpu
);