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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 struct cpumask *irq_create_affinity_masks(const struct cpumask *affinity, int nvec);
282 int irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec);
283 
284 #else /* CONFIG_SMP */
285 
286 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
287 {
288         return -EINVAL;
289 }
290 
291 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
292 {
293         return 0;
294 }
295 
296 static inline int irq_can_set_affinity(unsigned int irq)
297 {
298         return 0;
299 }
300 
301 static inline int irq_select_affinity(unsigned int irq)  { return 0; }
302 
303 static inline int irq_set_affinity_hint(unsigned int irq,
304                                         const struct cpumask *m)
305 {
306         return -EINVAL;
307 }
308 
309 static inline int
310 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
311 {
312         return 0;
313 }
314 
315 static inline struct cpumask *
316 irq_create_affinity_masks(const struct cpumask *affinity, int nvec)
317 {
318         return NULL;
319 }
320 
321 static inline int
322 irq_calc_affinity_vectors(const struct cpumask *affinity, int maxvec)
323 {
324         return maxvec;
325 }
326 
327 #endif /* CONFIG_SMP */
328 
329 /*
330  * Special lockdep variants of irq disabling/enabling.
331  * These should be used for locking constructs that
332  * know that a particular irq context which is disabled,
333  * and which is the only irq-context user of a lock,
334  * that it's safe to take the lock in the irq-disabled
335  * section without disabling hardirqs.
336  *
337  * On !CONFIG_LOCKDEP they are equivalent to the normal
338  * irq disable/enable methods.
339  */
340 static inline void disable_irq_nosync_lockdep(unsigned int irq)
341 {
342         disable_irq_nosync(irq);
343 #ifdef CONFIG_LOCKDEP
344         local_irq_disable();
345 #endif
346 }
347 
348 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
349 {
350         disable_irq_nosync(irq);
351 #ifdef CONFIG_LOCKDEP
352         local_irq_save(*flags);
353 #endif
354 }
355 
356 static inline void disable_irq_lockdep(unsigned int irq)
357 {
358         disable_irq(irq);
359 #ifdef CONFIG_LOCKDEP
360         local_irq_disable();
361 #endif
362 }
363 
364 static inline void enable_irq_lockdep(unsigned int irq)
365 {
366 #ifdef CONFIG_LOCKDEP
367         local_irq_enable();
368 #endif
369         enable_irq(irq);
370 }
371 
372 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
373 {
374 #ifdef CONFIG_LOCKDEP
375         local_irq_restore(*flags);
376 #endif
377         enable_irq(irq);
378 }
379 
380 /* IRQ wakeup (PM) control: */
381 extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
382 
383 static inline int enable_irq_wake(unsigned int irq)
384 {
385         return irq_set_irq_wake(irq, 1);
386 }
387 
388 static inline int disable_irq_wake(unsigned int irq)
389 {
390         return irq_set_irq_wake(irq, 0);
391 }
392 
393 /*
394  * irq_get_irqchip_state/irq_set_irqchip_state specific flags
395  */
396 enum irqchip_irq_state {
397         IRQCHIP_STATE_PENDING,          /* Is interrupt pending? */
398         IRQCHIP_STATE_ACTIVE,           /* Is interrupt in progress? */
399         IRQCHIP_STATE_MASKED,           /* Is interrupt masked? */
400         IRQCHIP_STATE_LINE_LEVEL,       /* Is IRQ line high? */
401 };
402 
403 extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
404                                  bool *state);
405 extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
406                                  bool state);
407 
408 #ifdef CONFIG_IRQ_FORCED_THREADING
409 extern bool force_irqthreads;
410 #else
411 #define force_irqthreads        (0)
412 #endif
413 
414 #ifndef __ARCH_SET_SOFTIRQ_PENDING
415 #define set_softirq_pending(x) (local_softirq_pending() = (x))
416 #define or_softirq_pending(x)  (local_softirq_pending() |= (x))
417 #endif
418 
419 /* Some architectures might implement lazy enabling/disabling of
420  * interrupts. In some cases, such as stop_machine, we might want
421  * to ensure that after a local_irq_disable(), interrupts have
422  * really been disabled in hardware. Such architectures need to
423  * implement the following hook.
424  */
425 #ifndef hard_irq_disable
426 #define hard_irq_disable()      do { } while(0)
427 #endif
428 
429 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
430    frequency threaded job scheduling. For almost all the purposes
431    tasklets are more than enough. F.e. all serial device BHs et
432    al. should be converted to tasklets, not to softirqs.
433  */
434 
435 enum
436 {
437         HI_SOFTIRQ=0,
438         TIMER_SOFTIRQ,
439         NET_TX_SOFTIRQ,
440         NET_RX_SOFTIRQ,
441         BLOCK_SOFTIRQ,
442         IRQ_POLL_SOFTIRQ,
443         TASKLET_SOFTIRQ,
444         SCHED_SOFTIRQ,
445         HRTIMER_SOFTIRQ, /* Unused, but kept as tools rely on the
446                             numbering. Sigh! */
447         RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
448 
449         NR_SOFTIRQS
450 };
451 
452 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
453 
454 /* map softirq index to softirq name. update 'softirq_to_name' in
455  * kernel/softirq.c when adding a new softirq.
456  */
457 extern const char * const softirq_to_name[NR_SOFTIRQS];
458 
459 /* softirq mask and active fields moved to irq_cpustat_t in
460  * asm/hardirq.h to get better cache usage.  KAO
461  */
462 
463 struct softirq_action
464 {
465         void    (*action)(struct softirq_action *);
466 };
467 
468 asmlinkage void do_softirq(void);
469 asmlinkage void __do_softirq(void);
470 
471 #ifdef __ARCH_HAS_DO_SOFTIRQ
472 void do_softirq_own_stack(void);
473 #else
474 static inline void do_softirq_own_stack(void)
475 {
476         __do_softirq();
477 }
478 #endif
479 
480 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
481 extern void softirq_init(void);
482 extern void __raise_softirq_irqoff(unsigned int nr);
483 
484 extern void raise_softirq_irqoff(unsigned int nr);
485 extern void raise_softirq(unsigned int nr);
486 
487 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
488 
489 static inline struct task_struct *this_cpu_ksoftirqd(void)
490 {
491         return this_cpu_read(ksoftirqd);
492 }
493 
494 /* Tasklets --- multithreaded analogue of BHs.
495 
496    Main feature differing them of generic softirqs: tasklet
497    is running only on one CPU simultaneously.
498 
499    Main feature differing them of BHs: different tasklets
500    may be run simultaneously on different CPUs.
501 
502    Properties:
503    * If tasklet_schedule() is called, then tasklet is guaranteed
504      to be executed on some cpu at least once after this.
505    * If the tasklet is already scheduled, but its execution is still not
506      started, it will be executed only once.
507    * If this tasklet is already running on another CPU (or schedule is called
508      from tasklet itself), it is rescheduled for later.
509    * Tasklet is strictly serialized wrt itself, but not
510      wrt another tasklets. If client needs some intertask synchronization,
511      he makes it with spinlocks.
512  */
513 
514 struct tasklet_struct
515 {
516         struct tasklet_struct *next;
517         unsigned long state;
518         atomic_t count;
519         void (*func)(unsigned long);
520         unsigned long data;
521 };
522 
523 #define DECLARE_TASKLET(name, func, data) \
524 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
525 
526 #define DECLARE_TASKLET_DISABLED(name, func, data) \
527 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
528 
529 
530 enum
531 {
532         TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
533         TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
534 };
535 
536 #ifdef CONFIG_SMP
537 static inline int tasklet_trylock(struct tasklet_struct *t)
538 {
539         return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
540 }
541 
542 static inline void tasklet_unlock(struct tasklet_struct *t)
543 {
544         smp_mb__before_atomic();
545         clear_bit(TASKLET_STATE_RUN, &(t)->state);
546 }
547 
548 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
549 {
550         while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
551 }
552 #else
553 #define tasklet_trylock(t) 1
554 #define tasklet_unlock_wait(t) do { } while (0)
555 #define tasklet_unlock(t) do { } while (0)
556 #endif
557 
558 extern void __tasklet_schedule(struct tasklet_struct *t);
559 
560 static inline void tasklet_schedule(struct tasklet_struct *t)
561 {
562         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
563                 __tasklet_schedule(t);
564 }
565 
566 extern void __tasklet_hi_schedule(struct tasklet_struct *t);
567 
568 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
569 {
570         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
571                 __tasklet_hi_schedule(t);
572 }
573 
574 extern void __tasklet_hi_schedule_first(struct tasklet_struct *t);
575 
576 /*
577  * This version avoids touching any other tasklets. Needed for kmemcheck
578  * in order not to take any page faults while enqueueing this tasklet;
579  * consider VERY carefully whether you really need this or
580  * tasklet_hi_schedule()...
581  */
582 static inline void tasklet_hi_schedule_first(struct tasklet_struct *t)
583 {
584         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
585                 __tasklet_hi_schedule_first(t);
586 }
587 
588 
589 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
590 {
591         atomic_inc(&t->count);
592         smp_mb__after_atomic();
593 }
594 
595 static inline void tasklet_disable(struct tasklet_struct *t)
596 {
597         tasklet_disable_nosync(t);
598         tasklet_unlock_wait(t);
599         smp_mb();
600 }
601 
602 static inline void tasklet_enable(struct tasklet_struct *t)
603 {
604         smp_mb__before_atomic();
605         atomic_dec(&t->count);
606 }
607 
608 extern void tasklet_kill(struct tasklet_struct *t);
609 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);
610 extern void tasklet_init(struct tasklet_struct *t,
611                          void (*func)(unsigned long), unsigned long data);
612 
613 struct tasklet_hrtimer {
614         struct hrtimer          timer;
615         struct tasklet_struct   tasklet;
616         enum hrtimer_restart    (*function)(struct hrtimer *);
617 };
618 
619 extern void
620 tasklet_hrtimer_init(struct tasklet_hrtimer *ttimer,
621                      enum hrtimer_restart (*function)(struct hrtimer *),
622                      clockid_t which_clock, enum hrtimer_mode mode);
623 
624 static inline
625 void tasklet_hrtimer_start(struct tasklet_hrtimer *ttimer, ktime_t time,
626                            const enum hrtimer_mode mode)
627 {
628         hrtimer_start(&ttimer->timer, time, mode);
629 }
630 
631 static inline
632 void tasklet_hrtimer_cancel(struct tasklet_hrtimer *ttimer)
633 {
634         hrtimer_cancel(&ttimer->timer);
635         tasklet_kill(&ttimer->tasklet);
636 }
637 
638 /*
639  * Autoprobing for irqs:
640  *
641  * probe_irq_on() and probe_irq_off() provide robust primitives
642  * for accurate IRQ probing during kernel initialization.  They are
643  * reasonably simple to use, are not "fooled" by spurious interrupts,
644  * and, unlike other attempts at IRQ probing, they do not get hung on
645  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
646  *
647  * For reasonably foolproof probing, use them as follows:
648  *
649  * 1. clear and/or mask the device's internal interrupt.
650  * 2. sti();
651  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
652  * 4. enable the device and cause it to trigger an interrupt.
653  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
654  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
655  * 7. service the device to clear its pending interrupt.
656  * 8. loop again if paranoia is required.
657  *
658  * probe_irq_on() returns a mask of allocated irq's.
659  *
660  * probe_irq_off() takes the mask as a parameter,
661  * and returns the irq number which occurred,
662  * or zero if none occurred, or a negative irq number
663  * if more than one irq occurred.
664  */
665 
666 #if !defined(CONFIG_GENERIC_IRQ_PROBE) 
667 static inline unsigned long probe_irq_on(void)
668 {
669         return 0;
670 }
671 static inline int probe_irq_off(unsigned long val)
672 {
673         return 0;
674 }
675 static inline unsigned int probe_irq_mask(unsigned long val)
676 {
677         return 0;
678 }
679 #else
680 extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
681 extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
682 extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
683 #endif
684 
685 #ifdef CONFIG_PROC_FS
686 /* Initialize /proc/irq/ */
687 extern void init_irq_proc(void);
688 #else
689 static inline void init_irq_proc(void)
690 {
691 }
692 #endif
693 
694 struct seq_file;
695 int show_interrupts(struct seq_file *p, void *v);
696 int arch_show_interrupts(struct seq_file *p, int prec);
697 
698 extern int early_irq_init(void);
699 extern int arch_probe_nr_irqs(void);
700 extern int arch_early_irq_init(void);
701 
702 #if defined(CONFIG_FUNCTION_GRAPH_TRACER) || defined(CONFIG_KASAN)
703 /*
704  * We want to know which function is an entrypoint of a hardirq or a softirq.
705  */
706 #define __irq_entry              __attribute__((__section__(".irqentry.text")))
707 #define __softirq_entry  \
708         __attribute__((__section__(".softirqentry.text")))
709 
710 /* Limits of hardirq entrypoints */
711 extern char __irqentry_text_start[];
712 extern char __irqentry_text_end[];
713 /* Limits of softirq entrypoints */
714 extern char __softirqentry_text_start[];
715 extern char __softirqentry_text_end[];
716 
717 #else
718 #define __irq_entry
719 #define __softirq_entry
720 #endif
721 
722 #endif
723 

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