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Linux/include/linux/interrupt.h

  1 /* interrupt.h */
  2 #ifndef _LINUX_INTERRUPT_H
  3 #define _LINUX_INTERRUPT_H
  4 
  5 #include <linux/kernel.h>
  6 #include <linux/linkage.h>
  7 #include <linux/bitops.h>
  8 #include <linux/preempt.h>
  9 #include <linux/cpumask.h>
 10 #include <linux/irqreturn.h>
 11 #include <linux/irqnr.h>
 12 #include <linux/hardirq.h>
 13 #include <linux/irqflags.h>
 14 #include <linux/hrtimer.h>
 15 #include <linux/kref.h>
 16 #include <linux/workqueue.h>
 17 
 18 #include <linux/atomic.h>
 19 #include <asm/ptrace.h>
 20 #include <asm/irq.h>
 21 
 22 /*
 23  * These correspond to the IORESOURCE_IRQ_* defines in
 24  * linux/ioport.h to select the interrupt line behaviour.  When
 25  * requesting an interrupt without specifying a IRQF_TRIGGER, the
 26  * setting should be assumed to be "as already configured", which
 27  * may be as per machine or firmware initialisation.
 28  */
 29 #define IRQF_TRIGGER_NONE       0x00000000
 30 #define IRQF_TRIGGER_RISING     0x00000001
 31 #define IRQF_TRIGGER_FALLING    0x00000002
 32 #define IRQF_TRIGGER_HIGH       0x00000004
 33 #define IRQF_TRIGGER_LOW        0x00000008
 34 #define IRQF_TRIGGER_MASK       (IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
 35                                  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
 36 #define IRQF_TRIGGER_PROBE      0x00000010
 37 
 38 /*
 39  * These flags used only by the kernel as part of the
 40  * irq handling routines.
 41  *
 42  * IRQF_SHARED - allow sharing the irq among several devices
 43  * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
 44  * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
 45  * IRQF_PERCPU - Interrupt is per cpu
 46  * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
 47  * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
 48  *                registered first in an shared interrupt is considered for
 49  *                performance reasons)
 50  * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
 51  *                Used by threaded interrupts which need to keep the
 52  *                irq line disabled until the threaded handler has been run.
 53  * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend.  Does not guarantee
 54  *                   that this interrupt will wake the system from a suspended
 55  *                   state.  See Documentation/power/suspend-and-interrupts.txt
 56  * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
 57  * IRQF_NO_THREAD - Interrupt cannot be threaded
 58  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
 59  *                resume time.
 60  * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this
 61  *                interrupt handler after suspending interrupts. For system
 62  *                wakeup devices users need to implement wakeup detection in
 63  *                their interrupt handlers.
 64  */
 65 #define IRQF_SHARED             0x00000080
 66 #define IRQF_PROBE_SHARED       0x00000100
 67 #define __IRQF_TIMER            0x00000200
 68 #define IRQF_PERCPU             0x00000400
 69 #define IRQF_NOBALANCING        0x00000800
 70 #define IRQF_IRQPOLL            0x00001000
 71 #define IRQF_ONESHOT            0x00002000
 72 #define IRQF_NO_SUSPEND         0x00004000
 73 #define IRQF_FORCE_RESUME       0x00008000
 74 #define IRQF_NO_THREAD          0x00010000
 75 #define IRQF_EARLY_RESUME       0x00020000
 76 #define IRQF_COND_SUSPEND       0x00040000
 77 
 78 #define IRQF_TIMER              (__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
 79 
 80 /*
 81  * These values can be returned by request_any_context_irq() and
 82  * describe the context the interrupt will be run in.
 83  *
 84  * IRQC_IS_HARDIRQ - interrupt runs in hardirq context
 85  * IRQC_IS_NESTED - interrupt runs in a nested threaded context
 86  */
 87 enum {
 88         IRQC_IS_HARDIRQ = 0,
 89         IRQC_IS_NESTED,
 90 };
 91 
 92 typedef irqreturn_t (*irq_handler_t)(int, void *);
 93 
 94 /**
 95  * struct irqaction - per interrupt action descriptor
 96  * @handler:    interrupt handler function
 97  * @name:       name of the device
 98  * @dev_id:     cookie to identify the device
 99  * @percpu_dev_id:      cookie to identify the device
100  * @next:       pointer to the next irqaction for shared interrupts
101  * @irq:        interrupt number
102  * @flags:      flags (see IRQF_* above)
103  * @thread_fn:  interrupt handler function for threaded interrupts
104  * @thread:     thread pointer for threaded interrupts
105  * @secondary:  pointer to secondary irqaction (force threading)
106  * @thread_flags:       flags related to @thread
107  * @thread_mask:        bitmask for keeping track of @thread activity
108  * @dir:        pointer to the proc/irq/NN/name entry
109  */
110 struct irqaction {
111         irq_handler_t           handler;
112         void                    *dev_id;
113         void __percpu           *percpu_dev_id;
114         struct irqaction        *next;
115         irq_handler_t           thread_fn;
116         struct task_struct      *thread;
117         struct irqaction        *secondary;
118         unsigned int            irq;
119         unsigned int            flags;
120         unsigned long           thread_flags;
121         unsigned long           thread_mask;
122         const char              *name;
123         struct proc_dir_entry   *dir;
124 } ____cacheline_internodealigned_in_smp;
125 
126 extern irqreturn_t no_action(int cpl, void *dev_id);
127 
128 /*
129  * If a (PCI) device interrupt is not connected we set dev->irq to
130  * IRQ_NOTCONNECTED. This causes request_irq() to fail with -ENOTCONN, so we
131  * can distingiush that case from other error returns.
132  *
133  * 0x80000000 is guaranteed to be outside the available range of interrupts
134  * and easy to distinguish from other possible incorrect values.
135  */
136 #define IRQ_NOTCONNECTED        (1U << 31)
137 
138 extern int __must_check
139 request_threaded_irq(unsigned int irq, irq_handler_t handler,
140                      irq_handler_t thread_fn,
141                      unsigned long flags, const char *name, void *dev);
142 
143 static inline int __must_check
144 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
145             const char *name, void *dev)
146 {
147         return request_threaded_irq(irq, handler, NULL, flags, name, dev);
148 }
149 
150 extern int __must_check
151 request_any_context_irq(unsigned int irq, irq_handler_t handler,
152                         unsigned long flags, const char *name, void *dev_id);
153 
154 extern int __must_check
155 request_percpu_irq(unsigned int irq, irq_handler_t handler,
156                    const char *devname, void __percpu *percpu_dev_id);
157 
158 extern void free_irq(unsigned int, void *);
159 extern void free_percpu_irq(unsigned int, void __percpu *);
160 
161 struct device;
162 
163 extern int __must_check
164 devm_request_threaded_irq(struct device *dev, unsigned int irq,
165                           irq_handler_t handler, irq_handler_t thread_fn,
166                           unsigned long irqflags, const char *devname,
167                           void *dev_id);
168 
169 static inline int __must_check
170 devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
171                  unsigned long irqflags, const char *devname, void *dev_id)
172 {
173         return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
174                                          devname, dev_id);
175 }
176 
177 extern int __must_check
178 devm_request_any_context_irq(struct device *dev, unsigned int irq,
179                  irq_handler_t handler, unsigned long irqflags,
180                  const char *devname, void *dev_id);
181 
182 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
183 
184 /*
185  * On lockdep we dont want to enable hardirqs in hardirq
186  * context. Use local_irq_enable_in_hardirq() to annotate
187  * kernel code that has to do this nevertheless (pretty much
188  * the only valid case is for old/broken hardware that is
189  * insanely slow).
190  *
191  * NOTE: in theory this might break fragile code that relies
192  * on hardirq delivery - in practice we dont seem to have such
193  * places left. So the only effect should be slightly increased
194  * irqs-off latencies.
195  */
196 #ifdef CONFIG_LOCKDEP
197 # define local_irq_enable_in_hardirq()  do { } while (0)
198 #else
199 # define local_irq_enable_in_hardirq()  local_irq_enable()
200 #endif
201 
202 extern void disable_irq_nosync(unsigned int irq);
203 extern bool disable_hardirq(unsigned int irq);
204 extern void disable_irq(unsigned int irq);
205 extern void disable_percpu_irq(unsigned int irq);
206 extern void enable_irq(unsigned int irq);
207 extern void enable_percpu_irq(unsigned int irq, unsigned int type);
208 extern bool irq_percpu_is_enabled(unsigned int irq);
209 extern void irq_wake_thread(unsigned int irq, void *dev_id);
210 
211 /* The following three functions are for the core kernel use only. */
212 extern void suspend_device_irqs(void);
213 extern void resume_device_irqs(void);
214 
215 /**
216  * struct irq_affinity_notify - context for notification of IRQ affinity changes
217  * @irq:                Interrupt to which notification applies
218  * @kref:               Reference count, for internal use
219  * @work:               Work item, for internal use
220  * @notify:             Function to be called on change.  This will be
221  *                      called in process context.
222  * @release:            Function to be called on release.  This will be
223  *                      called in process context.  Once registered, the
224  *                      structure must only be freed when this function is
225  *                      called or later.
226  */
227 struct irq_affinity_notify {
228         unsigned int irq;
229         struct kref kref;
230         struct work_struct work;
231         void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
232         void (*release)(struct kref *ref);
233 };
234 
235 #if defined(CONFIG_SMP)
236 
237 extern cpumask_var_t irq_default_affinity;
238 
239 /* Internal implementation. Use the helpers below */
240 extern int __irq_set_affinity(unsigned int irq, const struct cpumask *cpumask,
241                               bool force);
242 
243 /**
244  * irq_set_affinity - Set the irq affinity of a given irq
245  * @irq:        Interrupt to set affinity
246  * @cpumask:    cpumask
247  *
248  * Fails if cpumask does not contain an online CPU
249  */
250 static inline int
251 irq_set_affinity(unsigned int irq, const struct cpumask *cpumask)
252 {
253         return __irq_set_affinity(irq, cpumask, false);
254 }
255 
256 /**
257  * irq_force_affinity - Force the irq affinity of a given irq
258  * @irq:        Interrupt to set affinity
259  * @cpumask:    cpumask
260  *
261  * Same as irq_set_affinity, but without checking the mask against
262  * online cpus.
263  *
264  * Solely for low level cpu hotplug code, where we need to make per
265  * cpu interrupts affine before the cpu becomes online.
266  */
267 static inline int
268 irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
269 {
270         return __irq_set_affinity(irq, cpumask, true);
271 }
272 
273 extern int irq_can_set_affinity(unsigned int irq);
274 extern int irq_select_affinity(unsigned int irq);
275 
276 extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
277 
278 extern int
279 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
280 
281 #else /* CONFIG_SMP */
282 
283 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
284 {
285         return -EINVAL;
286 }
287 
288 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
289 {
290         return 0;
291 }
292 
293 static inline int irq_can_set_affinity(unsigned int irq)
294 {
295         return 0;
296 }
297 
298 static inline int irq_select_affinity(unsigned int irq)  { return 0; }
299 
300 static inline int irq_set_affinity_hint(unsigned int irq,
301                                         const struct cpumask *m)
302 {
303         return -EINVAL;
304 }
305 
306 static inline int
307 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
308 {
309         return 0;
310 }
311 #endif /* CONFIG_SMP */
312 
313 /*
314  * Special lockdep variants of irq disabling/enabling.
315  * These should be used for locking constructs that
316  * know that a particular irq context which is disabled,
317  * and which is the only irq-context user of a lock,
318  * that it's safe to take the lock in the irq-disabled
319  * section without disabling hardirqs.
320  *
321  * On !CONFIG_LOCKDEP they are equivalent to the normal
322  * irq disable/enable methods.
323  */
324 static inline void disable_irq_nosync_lockdep(unsigned int irq)
325 {
326         disable_irq_nosync(irq);
327 #ifdef CONFIG_LOCKDEP
328         local_irq_disable();
329 #endif
330 }
331 
332 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
333 {
334         disable_irq_nosync(irq);
335 #ifdef CONFIG_LOCKDEP
336         local_irq_save(*flags);
337 #endif
338 }
339 
340 static inline void disable_irq_lockdep(unsigned int irq)
341 {
342         disable_irq(irq);
343 #ifdef CONFIG_LOCKDEP
344         local_irq_disable();
345 #endif
346 }
347 
348 static inline void enable_irq_lockdep(unsigned int irq)
349 {
350 #ifdef CONFIG_LOCKDEP
351         local_irq_enable();
352 #endif
353         enable_irq(irq);
354 }
355 
356 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
357 {
358 #ifdef CONFIG_LOCKDEP
359         local_irq_restore(*flags);
360 #endif
361         enable_irq(irq);
362 }
363 
364 /* IRQ wakeup (PM) control: */
365 extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
366 
367 static inline int enable_irq_wake(unsigned int irq)
368 {
369         return irq_set_irq_wake(irq, 1);
370 }
371 
372 static inline int disable_irq_wake(unsigned int irq)
373 {
374         return irq_set_irq_wake(irq, 0);
375 }
376 
377 /*
378  * irq_get_irqchip_state/irq_set_irqchip_state specific flags
379  */
380 enum irqchip_irq_state {
381         IRQCHIP_STATE_PENDING,          /* Is interrupt pending? */
382         IRQCHIP_STATE_ACTIVE,           /* Is interrupt in progress? */
383         IRQCHIP_STATE_MASKED,           /* Is interrupt masked? */
384         IRQCHIP_STATE_LINE_LEVEL,       /* Is IRQ line high? */
385 };
386 
387 extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
388                                  bool *state);
389 extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
390                                  bool state);
391 
392 #ifdef CONFIG_IRQ_FORCED_THREADING
393 extern bool force_irqthreads;
394 #else
395 #define force_irqthreads        (0)
396 #endif
397 
398 #ifndef __ARCH_SET_SOFTIRQ_PENDING
399 #define set_softirq_pending(x) (local_softirq_pending() = (x))
400 #define or_softirq_pending(x)  (local_softirq_pending() |= (x))
401 #endif
402 
403 /* Some architectures might implement lazy enabling/disabling of
404  * interrupts. In some cases, such as stop_machine, we might want
405  * to ensure that after a local_irq_disable(), interrupts have
406  * really been disabled in hardware. Such architectures need to
407  * implement the following hook.
408  */
409 #ifndef hard_irq_disable
410 #define hard_irq_disable()      do { } while(0)
411 #endif
412 
413 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
414    frequency threaded job scheduling. For almost all the purposes
415    tasklets are more than enough. F.e. all serial device BHs et
416    al. should be converted to tasklets, not to softirqs.
417  */
418 
419 enum
420 {
421         HI_SOFTIRQ=0,
422         TIMER_SOFTIRQ,
423         NET_TX_SOFTIRQ,
424         NET_RX_SOFTIRQ,
425         BLOCK_SOFTIRQ,
426         IRQ_POLL_SOFTIRQ,
427         TASKLET_SOFTIRQ,
428         SCHED_SOFTIRQ,
429         HRTIMER_SOFTIRQ, /* Unused, but kept as tools rely on the
430                             numbering. Sigh! */
431         RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
432 
433         NR_SOFTIRQS
434 };
435 
436 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
437 
438 /* map softirq index to softirq name. update 'softirq_to_name' in
439  * kernel/softirq.c when adding a new softirq.
440  */
441 extern const char * const softirq_to_name[NR_SOFTIRQS];
442 
443 /* softirq mask and active fields moved to irq_cpustat_t in
444  * asm/hardirq.h to get better cache usage.  KAO
445  */
446 
447 struct softirq_action
448 {
449         void    (*action)(struct softirq_action *);
450 };
451 
452 asmlinkage void do_softirq(void);
453 asmlinkage void __do_softirq(void);
454 
455 #ifdef __ARCH_HAS_DO_SOFTIRQ
456 void do_softirq_own_stack(void);
457 #else
458 static inline void do_softirq_own_stack(void)
459 {
460         __do_softirq();
461 }
462 #endif
463 
464 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
465 extern void softirq_init(void);
466 extern void __raise_softirq_irqoff(unsigned int nr);
467 
468 extern void raise_softirq_irqoff(unsigned int nr);
469 extern void raise_softirq(unsigned int nr);
470 
471 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
472 
473 static inline struct task_struct *this_cpu_ksoftirqd(void)
474 {
475         return this_cpu_read(ksoftirqd);
476 }
477 
478 /* Tasklets --- multithreaded analogue of BHs.
479 
480    Main feature differing them of generic softirqs: tasklet
481    is running only on one CPU simultaneously.
482 
483    Main feature differing them of BHs: different tasklets
484    may be run simultaneously on different CPUs.
485 
486    Properties:
487    * If tasklet_schedule() is called, then tasklet is guaranteed
488      to be executed on some cpu at least once after this.
489    * If the tasklet is already scheduled, but its execution is still not
490      started, it will be executed only once.
491    * If this tasklet is already running on another CPU (or schedule is called
492      from tasklet itself), it is rescheduled for later.
493    * Tasklet is strictly serialized wrt itself, but not
494      wrt another tasklets. If client needs some intertask synchronization,
495      he makes it with spinlocks.
496  */
497 
498 struct tasklet_struct
499 {
500         struct tasklet_struct *next;
501         unsigned long state;
502         atomic_t count;
503         void (*func)(unsigned long);
504         unsigned long data;
505 };
506 
507 #define DECLARE_TASKLET(name, func, data) \
508 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
509 
510 #define DECLARE_TASKLET_DISABLED(name, func, data) \
511 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
512 
513 
514 enum
515 {
516         TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
517         TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
518 };
519 
520 #ifdef CONFIG_SMP
521 static inline int tasklet_trylock(struct tasklet_struct *t)
522 {
523         return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
524 }
525 
526 static inline void tasklet_unlock(struct tasklet_struct *t)
527 {
528         smp_mb__before_atomic();
529         clear_bit(TASKLET_STATE_RUN, &(t)->state);
530 }
531 
532 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
533 {
534         while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
535 }
536 #else
537 #define tasklet_trylock(t) 1
538 #define tasklet_unlock_wait(t) do { } while (0)
539 #define tasklet_unlock(t) do { } while (0)
540 #endif
541 
542 extern void __tasklet_schedule(struct tasklet_struct *t);
543 
544 static inline void tasklet_schedule(struct tasklet_struct *t)
545 {
546         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
547                 __tasklet_schedule(t);
548 }
549 
550 extern void __tasklet_hi_schedule(struct tasklet_struct *t);
551 
552 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
553 {
554         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
555                 __tasklet_hi_schedule(t);
556 }
557 
558 extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
559 
560 /*
561  * This version avoids touching any other tasklets. Needed for kmemcheck
562  * in order not to take any page faults while enqueueing this tasklet;
563  * consider VERY carefully whether you really need this or
564  * tasklet_hi_schedule()...
565  */
566 static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
567 {
568         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
569                 __tasklet_hi_schedule_first(t);
570 }
571 
572 
573 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
574 {
575         atomic_inc(&t->count);
576         smp_mb__after_atomic();
577 }
578 
579 static inline void tasklet_disable(struct tasklet_struct *t)
580 {
581         tasklet_disable_nosync(t);
582         tasklet_unlock_wait(t);
583         smp_mb();
584 }
585 
586 static inline void tasklet_enable(struct tasklet_struct *t)
587 {
588         smp_mb__before_atomic();
589         atomic_dec(&t->count);
590 }
591 
592 extern void tasklet_kill(struct tasklet_struct *t);
593 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
594 extern void tasklet_init(struct tasklet_struct *t,
595                          void (*func)(unsigned long), unsigned long data);
596 
597 struct tasklet_hrtimer {
598         struct hrtimer          timer;
599         struct tasklet_struct   tasklet;
600         enum hrtimer_restart    (*function)(struct hrtimer *);
601 };
602 
603 extern void
604 tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
605                      enum hrtimer_restart (*function)(struct hrtimer *),
606                      clockid_t which_clock, enum hrtimer_mode mode);
607 
608 static inline
609 void tasklet_hrtimer_start(struct tasklet_hrtimer *ttimer, ktime_t time,
610                            const enum hrtimer_mode mode)
611 {
612         hrtimer_start(&ttimer->timer, time, mode);
613 }
614 
615 static inline
616 void tasklet_hrtimer_cancel(struct tasklet_hrtimer *ttimer)
617 {
618         hrtimer_cancel(&ttimer->timer);
619         tasklet_kill(&ttimer->tasklet);
620 }
621 
622 /*
623  * Autoprobing for irqs:
624  *
625  * probe_irq_on() and probe_irq_off() provide robust primitives
626  * for accurate IRQ probing during kernel initialization.  They are
627  * reasonably simple to use, are not "fooled" by spurious interrupts,
628  * and, unlike other attempts at IRQ probing, they do not get hung on
629  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
630  *
631  * For reasonably foolproof probing, use them as follows:
632  *
633  * 1. clear and/or mask the device's internal interrupt.
634  * 2. sti();
635  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
636  * 4. enable the device and cause it to trigger an interrupt.
637  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
638  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
639  * 7. service the device to clear its pending interrupt.
640  * 8. loop again if paranoia is required.
641  *
642  * probe_irq_on() returns a mask of allocated irq's.
643  *
644  * probe_irq_off() takes the mask as a parameter,
645  * and returns the irq number which occurred,
646  * or zero if none occurred, or a negative irq number
647  * if more than one irq occurred.
648  */
649 
650 #if !defined(CONFIG_GENERIC_IRQ_PROBE) 
651 static inline unsigned long probe_irq_on(void)
652 {
653         return 0;
654 }
655 static inline int probe_irq_off(unsigned long val)
656 {
657         return 0;
658 }
659 static inline unsigned int probe_irq_mask(unsigned long val)
660 {
661         return 0;
662 }
663 #else
664 extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
665 extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
666 extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
667 #endif
668 
669 #ifdef CONFIG_PROC_FS
670 /* Initialize /proc/irq/ */
671 extern void init_irq_proc(void);
672 #else
673 static inline void init_irq_proc(void)
674 {
675 }
676 #endif
677 
678 struct seq_file;
679 int show_interrupts(struct seq_file *p, void *v);
680 int arch_show_interrupts(struct seq_file *p, int prec);
681 
682 extern int early_irq_init(void);
683 extern int arch_probe_nr_irqs(void);
684 extern int arch_early_irq_init(void);
685 
686 #if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
687 /*
688  * We want to know which function is an entrypoint of a hardirq or a softirq.
689  */
690 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
691 #define __softirq_entry  \
692         __attribute__((__section__(".softirqentry.text")))
693 
694 /* Limits of hardirq entrypoints */
695 extern char __irqentry_text_start[];
696 extern char __irqentry_text_end[];
697 /* Limits of softirq entrypoints */
698 extern char __softirqentry_text_start[];
699 extern char __softirqentry_text_end[];
700 
701 #else
702 #define __irq_entry
703 #define __softirq_entry
704 #endif
705 
706 #endif
707 

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