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1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* interrupt.h */
3 #ifndef _LINUX_INTERRUPT_H
4 #define _LINUX_INTERRUPT_H
5 
6 #include <linux/kernel.h>
7 #include <linux/bitops.h>
8 #include <linux/cpumask.h>
9 #include <linux/irqreturn.h>
10 #include <linux/irqnr.h>
11 #include <linux/hardirq.h>
12 #include <linux/irqflags.h>
13 #include <linux/hrtimer.h>
14 #include <linux/kref.h>
15 #include <linux/workqueue.h>
16 #include <linux/jump_label.h>
17 
18 #include <linux/atomic.h>
19 #include <asm/ptrace.h>
20 #include <asm/irq.h>
21 #include <asm/sections.h>
22 
23 /*
24  * These correspond to the IORESOURCE_IRQ_* defines in
25  * linux/ioport.h to select the interrupt line behaviour.  When
26  * requesting an interrupt without specifying a IRQF_TRIGGER, the
27  * setting should be assumed to be "as already configured", which
28  * may be as per machine or firmware initialisation.
29  */
30 #define IRQF_TRIGGER_NONE	0x00000000
31 #define IRQF_TRIGGER_RISING	0x00000001
32 #define IRQF_TRIGGER_FALLING	0x00000002
33 #define IRQF_TRIGGER_HIGH	0x00000004
34 #define IRQF_TRIGGER_LOW	0x00000008
35 #define IRQF_TRIGGER_MASK	(IRQF_TRIGGER_HIGH | IRQF_TRIGGER_LOW | \
36 				 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING)
37 #define IRQF_TRIGGER_PROBE	0x00000010
38 
39 /*
40  * These flags used only by the kernel as part of the
41  * irq handling routines.
42  *
43  * IRQF_SHARED - allow sharing the irq among several devices
44  * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
45  * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
46  * IRQF_PERCPU - Interrupt is per cpu
47  * IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing
48  * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is
49  *                registered first in a shared interrupt is considered for
50  *                performance reasons)
51  * IRQF_ONESHOT - Interrupt is not reenabled after the hardirq handler finished.
52  *                Used by threaded interrupts which need to keep the
53  *                irq line disabled until the threaded handler has been run.
54  * IRQF_NO_SUSPEND - Do not disable this IRQ during suspend.  Does not guarantee
55  *                   that this interrupt will wake the system from a suspended
56  *                   state.  See Documentation/power/suspend-and-interrupts.rst
57  * IRQF_FORCE_RESUME - Force enable it on resume even if IRQF_NO_SUSPEND is set
58  * IRQF_NO_THREAD - Interrupt cannot be threaded
59  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
60  *                resume time.
61  * IRQF_COND_SUSPEND - If the IRQ is shared with a NO_SUSPEND user, execute this
62  *                interrupt handler after suspending interrupts. For system
63  *                wakeup devices users need to implement wakeup detection in
64  *                their interrupt handlers.
65  * IRQF_NO_AUTOEN - Don't enable IRQ or NMI automatically when users request it.
66  *                Users will enable it explicitly by enable_irq() or enable_nmi()
67  *                later.
68  * IRQF_NO_DEBUG - Exclude from runnaway detection for IPI and similar handlers,
69  *		   depends on IRQF_PERCPU.
70  */
71 #define IRQF_SHARED		0x00000080
72 #define IRQF_PROBE_SHARED	0x00000100
73 #define __IRQF_TIMER		0x00000200
74 #define IRQF_PERCPU		0x00000400
75 #define IRQF_NOBALANCING	0x00000800
76 #define IRQF_IRQPOLL		0x00001000
77 #define IRQF_ONESHOT		0x00002000
78 #define IRQF_NO_SUSPEND		0x00004000
79 #define IRQF_FORCE_RESUME	0x00008000
80 #define IRQF_NO_THREAD		0x00010000
81 #define IRQF_EARLY_RESUME	0x00020000
82 #define IRQF_COND_SUSPEND	0x00040000
83 #define IRQF_NO_AUTOEN		0x00080000
84 #define IRQF_NO_DEBUG		0x00100000
85 
86 #define IRQF_TIMER		(__IRQF_TIMER | IRQF_NO_SUSPEND | IRQF_NO_THREAD)
87 
88 /*
89  * These values can be returned by request_any_context_irq() and
90  * describe the context the interrupt will be run in.
91  *
92  * IRQC_IS_HARDIRQ - interrupt runs in hardirq context
93  * IRQC_IS_NESTED - interrupt runs in a nested threaded context
94  */
95 enum {
96 	IRQC_IS_HARDIRQ	= 0,
97 	IRQC_IS_NESTED,
98 };
99 
100 typedef irqreturn_t (*irq_handler_t)(int, void *);
101 
102 /**
103  * struct irqaction - per interrupt action descriptor
104  * @handler:	interrupt handler function
105  * @name:	name of the device
106  * @dev_id:	cookie to identify the device
107  * @percpu_dev_id:	cookie to identify the device
108  * @next:	pointer to the next irqaction for shared interrupts
109  * @irq:	interrupt number
110  * @flags:	flags (see IRQF_* above)
111  * @thread_fn:	interrupt handler function for threaded interrupts
112  * @thread:	thread pointer for threaded interrupts
113  * @secondary:	pointer to secondary irqaction (force threading)
114  * @thread_flags:	flags related to @thread
115  * @thread_mask:	bitmask for keeping track of @thread activity
116  * @dir:	pointer to the proc/irq/NN/name entry
117  */
118 struct irqaction {
119 	irq_handler_t		handler;
120 	void			*dev_id;
121 	void __percpu		*percpu_dev_id;
122 	struct irqaction	*next;
123 	irq_handler_t		thread_fn;
124 	struct task_struct	*thread;
125 	struct irqaction	*secondary;
126 	unsigned int		irq;
127 	unsigned int		flags;
128 	unsigned long		thread_flags;
129 	unsigned long		thread_mask;
130 	const char		*name;
131 	struct proc_dir_entry	*dir;
132 } ____cacheline_internodealigned_in_smp;
133 
134 extern irqreturn_t no_action(int cpl, void *dev_id);
135 
136 /*
137  * If a (PCI) device interrupt is not connected we set dev->irq to
138  * IRQ_NOTCONNECTED. This causes request_irq() to fail with -ENOTCONN, so we
139  * can distingiush that case from other error returns.
140  *
141  * 0x80000000 is guaranteed to be outside the available range of interrupts
142  * and easy to distinguish from other possible incorrect values.
143  */
144 #define IRQ_NOTCONNECTED	(1U << 31)
145 
146 extern int __must_check
147 request_threaded_irq(unsigned int irq, irq_handler_t handler,
148 		     irq_handler_t thread_fn,
149 		     unsigned long flags, const char *name, void *dev);
150 
151 /**
152  * request_irq - Add a handler for an interrupt line
153  * @irq:	The interrupt line to allocate
154  * @handler:	Function to be called when the IRQ occurs.
155  *		Primary handler for threaded interrupts
156  *		If NULL, the default primary handler is installed
157  * @flags:	Handling flags
158  * @name:	Name of the device generating this interrupt
159  * @dev:	A cookie passed to the handler function
160  *
161  * This call allocates an interrupt and establishes a handler; see
162  * the documentation for request_threaded_irq() for details.
163  */
164 static inline int __must_check
request_irq(unsigned int irq,irq_handler_t handler,unsigned long flags,const char * name,void * dev)165 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
166 	    const char *name, void *dev)
167 {
168 	return request_threaded_irq(irq, handler, NULL, flags, name, dev);
169 }
170 
171 extern int __must_check
172 request_any_context_irq(unsigned int irq, irq_handler_t handler,
173 			unsigned long flags, const char *name, void *dev_id);
174 
175 extern int __must_check
176 __request_percpu_irq(unsigned int irq, irq_handler_t handler,
177 		     unsigned long flags, const char *devname,
178 		     void __percpu *percpu_dev_id);
179 
180 extern int __must_check
181 request_nmi(unsigned int irq, irq_handler_t handler, unsigned long flags,
182 	    const char *name, void *dev);
183 
184 static inline int __must_check
request_percpu_irq(unsigned int irq,irq_handler_t handler,const char * devname,void __percpu * percpu_dev_id)185 request_percpu_irq(unsigned int irq, irq_handler_t handler,
186 		   const char *devname, void __percpu *percpu_dev_id)
187 {
188 	return __request_percpu_irq(irq, handler, 0,
189 				    devname, percpu_dev_id);
190 }
191 
192 extern int __must_check
193 request_percpu_nmi(unsigned int irq, irq_handler_t handler,
194 		   const char *devname, void __percpu *dev);
195 
196 extern const void *free_irq(unsigned int, void *);
197 extern void free_percpu_irq(unsigned int, void __percpu *);
198 
199 extern const void *free_nmi(unsigned int irq, void *dev_id);
200 extern void free_percpu_nmi(unsigned int irq, void __percpu *percpu_dev_id);
201 
202 struct device;
203 
204 extern int __must_check
205 devm_request_threaded_irq(struct device *dev, unsigned int irq,
206 			  irq_handler_t handler, irq_handler_t thread_fn,
207 			  unsigned long irqflags, const char *devname,
208 			  void *dev_id);
209 
210 static inline int __must_check
devm_request_irq(struct device * dev,unsigned int irq,irq_handler_t handler,unsigned long irqflags,const char * devname,void * dev_id)211 devm_request_irq(struct device *dev, unsigned int irq, irq_handler_t handler,
212 		 unsigned long irqflags, const char *devname, void *dev_id)
213 {
214 	return devm_request_threaded_irq(dev, irq, handler, NULL, irqflags,
215 					 devname, dev_id);
216 }
217 
218 extern int __must_check
219 devm_request_any_context_irq(struct device *dev, unsigned int irq,
220 		 irq_handler_t handler, unsigned long irqflags,
221 		 const char *devname, void *dev_id);
222 
223 extern void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id);
224 
225 /*
226  * On lockdep we dont want to enable hardirqs in hardirq
227  * context. Use local_irq_enable_in_hardirq() to annotate
228  * kernel code that has to do this nevertheless (pretty much
229  * the only valid case is for old/broken hardware that is
230  * insanely slow).
231  *
232  * NOTE: in theory this might break fragile code that relies
233  * on hardirq delivery - in practice we dont seem to have such
234  * places left. So the only effect should be slightly increased
235  * irqs-off latencies.
236  */
237 #ifdef CONFIG_LOCKDEP
238 # define local_irq_enable_in_hardirq()	do { } while (0)
239 #else
240 # define local_irq_enable_in_hardirq()	local_irq_enable()
241 #endif
242 
243 bool irq_has_action(unsigned int irq);
244 extern void disable_irq_nosync(unsigned int irq);
245 extern bool disable_hardirq(unsigned int irq);
246 extern void disable_irq(unsigned int irq);
247 extern void disable_percpu_irq(unsigned int irq);
248 extern void enable_irq(unsigned int irq);
249 extern void enable_percpu_irq(unsigned int irq, unsigned int type);
250 extern bool irq_percpu_is_enabled(unsigned int irq);
251 extern void irq_wake_thread(unsigned int irq, void *dev_id);
252 
253 extern void disable_nmi_nosync(unsigned int irq);
254 extern void disable_percpu_nmi(unsigned int irq);
255 extern void enable_nmi(unsigned int irq);
256 extern void enable_percpu_nmi(unsigned int irq, unsigned int type);
257 extern int prepare_percpu_nmi(unsigned int irq);
258 extern void teardown_percpu_nmi(unsigned int irq);
259 
260 extern int irq_inject_interrupt(unsigned int irq);
261 
262 /* The following three functions are for the core kernel use only. */
263 extern void suspend_device_irqs(void);
264 extern void resume_device_irqs(void);
265 extern void rearm_wake_irq(unsigned int irq);
266 
267 /**
268  * struct irq_affinity_notify - context for notification of IRQ affinity changes
269  * @irq:		Interrupt to which notification applies
270  * @kref:		Reference count, for internal use
271  * @work:		Work item, for internal use
272  * @notify:		Function to be called on change.  This will be
273  *			called in process context.
274  * @release:		Function to be called on release.  This will be
275  *			called in process context.  Once registered, the
276  *			structure must only be freed when this function is
277  *			called or later.
278  */
279 struct irq_affinity_notify {
280 	unsigned int irq;
281 	struct kref kref;
282 	struct work_struct work;
283 	void (*notify)(struct irq_affinity_notify *, const cpumask_t *mask);
284 	void (*release)(struct kref *ref);
285 };
286 
287 #define	IRQ_AFFINITY_MAX_SETS  4
288 
289 /**
290  * struct irq_affinity - Description for automatic irq affinity assignements
291  * @pre_vectors:	Don't apply affinity to @pre_vectors at beginning of
292  *			the MSI(-X) vector space
293  * @post_vectors:	Don't apply affinity to @post_vectors at end of
294  *			the MSI(-X) vector space
295  * @nr_sets:		The number of interrupt sets for which affinity
296  *			spreading is required
297  * @set_size:		Array holding the size of each interrupt set
298  * @calc_sets:		Callback for calculating the number and size
299  *			of interrupt sets
300  * @priv:		Private data for usage by @calc_sets, usually a
301  *			pointer to driver/device specific data.
302  */
303 struct irq_affinity {
304 	unsigned int	pre_vectors;
305 	unsigned int	post_vectors;
306 	unsigned int	nr_sets;
307 	unsigned int	set_size[IRQ_AFFINITY_MAX_SETS];
308 	void		(*calc_sets)(struct irq_affinity *, unsigned int nvecs);
309 	void		*priv;
310 };
311 
312 /**
313  * struct irq_affinity_desc - Interrupt affinity descriptor
314  * @mask:	cpumask to hold the affinity assignment
315  * @is_managed: 1 if the interrupt is managed internally
316  */
317 struct irq_affinity_desc {
318 	struct cpumask	mask;
319 	unsigned int	is_managed : 1;
320 };
321 
322 #if defined(CONFIG_SMP)
323 
324 extern cpumask_var_t irq_default_affinity;
325 
326 extern int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask);
327 extern int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask);
328 
329 extern int irq_can_set_affinity(unsigned int irq);
330 extern int irq_select_affinity(unsigned int irq);
331 
332 extern int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m);
333 extern int irq_update_affinity_desc(unsigned int irq,
334 				    struct irq_affinity_desc *affinity);
335 
336 extern int
337 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify);
338 
339 struct irq_affinity_desc *
340 irq_create_affinity_masks(unsigned int nvec, struct irq_affinity *affd);
341 
342 unsigned int irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
343 				       const struct irq_affinity *affd);
344 
345 #else /* CONFIG_SMP */
346 
irq_set_affinity(unsigned int irq,const struct cpumask * m)347 static inline int irq_set_affinity(unsigned int irq, const struct cpumask *m)
348 {
349 	return -EINVAL;
350 }
351 
irq_force_affinity(unsigned int irq,const struct cpumask * cpumask)352 static inline int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask)
353 {
354 	return 0;
355 }
356 
irq_can_set_affinity(unsigned int irq)357 static inline int irq_can_set_affinity(unsigned int irq)
358 {
359 	return 0;
360 }
361 
irq_select_affinity(unsigned int irq)362 static inline int irq_select_affinity(unsigned int irq)  { return 0; }
363 
irq_set_affinity_hint(unsigned int irq,const struct cpumask * m)364 static inline int irq_set_affinity_hint(unsigned int irq,
365 					const struct cpumask *m)
366 {
367 	return -EINVAL;
368 }
369 
irq_update_affinity_desc(unsigned int irq,struct irq_affinity_desc * affinity)370 static inline int irq_update_affinity_desc(unsigned int irq,
371 					   struct irq_affinity_desc *affinity)
372 {
373 	return -EINVAL;
374 }
375 
376 static inline int
irq_set_affinity_notifier(unsigned int irq,struct irq_affinity_notify * notify)377 irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
378 {
379 	return 0;
380 }
381 
382 static inline struct irq_affinity_desc *
irq_create_affinity_masks(unsigned int nvec,struct irq_affinity * affd)383 irq_create_affinity_masks(unsigned int nvec, struct irq_affinity *affd)
384 {
385 	return NULL;
386 }
387 
388 static inline unsigned int
irq_calc_affinity_vectors(unsigned int minvec,unsigned int maxvec,const struct irq_affinity * affd)389 irq_calc_affinity_vectors(unsigned int minvec, unsigned int maxvec,
390 			  const struct irq_affinity *affd)
391 {
392 	return maxvec;
393 }
394 
395 #endif /* CONFIG_SMP */
396 
397 /*
398  * Special lockdep variants of irq disabling/enabling.
399  * These should be used for locking constructs that
400  * know that a particular irq context which is disabled,
401  * and which is the only irq-context user of a lock,
402  * that it's safe to take the lock in the irq-disabled
403  * section without disabling hardirqs.
404  *
405  * On !CONFIG_LOCKDEP they are equivalent to the normal
406  * irq disable/enable methods.
407  */
disable_irq_nosync_lockdep(unsigned int irq)408 static inline void disable_irq_nosync_lockdep(unsigned int irq)
409 {
410 	disable_irq_nosync(irq);
411 #ifdef CONFIG_LOCKDEP
412 	local_irq_disable();
413 #endif
414 }
415 
disable_irq_nosync_lockdep_irqsave(unsigned int irq,unsigned long * flags)416 static inline void disable_irq_nosync_lockdep_irqsave(unsigned int irq, unsigned long *flags)
417 {
418 	disable_irq_nosync(irq);
419 #ifdef CONFIG_LOCKDEP
420 	local_irq_save(*flags);
421 #endif
422 }
423 
disable_irq_lockdep(unsigned int irq)424 static inline void disable_irq_lockdep(unsigned int irq)
425 {
426 	disable_irq(irq);
427 #ifdef CONFIG_LOCKDEP
428 	local_irq_disable();
429 #endif
430 }
431 
enable_irq_lockdep(unsigned int irq)432 static inline void enable_irq_lockdep(unsigned int irq)
433 {
434 #ifdef CONFIG_LOCKDEP
435 	local_irq_enable();
436 #endif
437 	enable_irq(irq);
438 }
439 
enable_irq_lockdep_irqrestore(unsigned int irq,unsigned long * flags)440 static inline void enable_irq_lockdep_irqrestore(unsigned int irq, unsigned long *flags)
441 {
442 #ifdef CONFIG_LOCKDEP
443 	local_irq_restore(*flags);
444 #endif
445 	enable_irq(irq);
446 }
447 
448 /* IRQ wakeup (PM) control: */
449 extern int irq_set_irq_wake(unsigned int irq, unsigned int on);
450 
enable_irq_wake(unsigned int irq)451 static inline int enable_irq_wake(unsigned int irq)
452 {
453 	return irq_set_irq_wake(irq, 1);
454 }
455 
disable_irq_wake(unsigned int irq)456 static inline int disable_irq_wake(unsigned int irq)
457 {
458 	return irq_set_irq_wake(irq, 0);
459 }
460 
461 /*
462  * irq_get_irqchip_state/irq_set_irqchip_state specific flags
463  */
464 enum irqchip_irq_state {
465 	IRQCHIP_STATE_PENDING,		/* Is interrupt pending? */
466 	IRQCHIP_STATE_ACTIVE,		/* Is interrupt in progress? */
467 	IRQCHIP_STATE_MASKED,		/* Is interrupt masked? */
468 	IRQCHIP_STATE_LINE_LEVEL,	/* Is IRQ line high? */
469 };
470 
471 extern int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
472 				 bool *state);
473 extern int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
474 				 bool state);
475 
476 #ifdef CONFIG_IRQ_FORCED_THREADING
477 # ifdef CONFIG_PREEMPT_RT
478 #  define force_irqthreads()	(true)
479 # else
480 DECLARE_STATIC_KEY_FALSE(force_irqthreads_key);
481 #  define force_irqthreads()	(static_branch_unlikely(&force_irqthreads_key))
482 # endif
483 #else
484 #define force_irqthreads()	(false)
485 #endif
486 
487 #ifndef local_softirq_pending
488 
489 #ifndef local_softirq_pending_ref
490 #define local_softirq_pending_ref irq_stat.__softirq_pending
491 #endif
492 
493 #define local_softirq_pending()	(__this_cpu_read(local_softirq_pending_ref))
494 #define set_softirq_pending(x)	(__this_cpu_write(local_softirq_pending_ref, (x)))
495 #define or_softirq_pending(x)	(__this_cpu_or(local_softirq_pending_ref, (x)))
496 
497 #endif /* local_softirq_pending */
498 
499 /* Some architectures might implement lazy enabling/disabling of
500  * interrupts. In some cases, such as stop_machine, we might want
501  * to ensure that after a local_irq_disable(), interrupts have
502  * really been disabled in hardware. Such architectures need to
503  * implement the following hook.
504  */
505 #ifndef hard_irq_disable
506 #define hard_irq_disable()	do { } while(0)
507 #endif
508 
509 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
510    frequency threaded job scheduling. For almost all the purposes
511    tasklets are more than enough. F.e. all serial device BHs et
512    al. should be converted to tasklets, not to softirqs.
513  */
514 
515 enum
516 {
517 	HI_SOFTIRQ=0,
518 	TIMER_SOFTIRQ,
519 	NET_TX_SOFTIRQ,
520 	NET_RX_SOFTIRQ,
521 	BLOCK_SOFTIRQ,
522 	IRQ_POLL_SOFTIRQ,
523 	TASKLET_SOFTIRQ,
524 	SCHED_SOFTIRQ,
525 	HRTIMER_SOFTIRQ,
526 	RCU_SOFTIRQ,    /* Preferable RCU should always be the last softirq */
527 
528 	NR_SOFTIRQS
529 };
530 
531 #define SOFTIRQ_STOP_IDLE_MASK (~(1 << RCU_SOFTIRQ))
532 /* Softirq's where the handling might be long: */
533 #define LONG_SOFTIRQ_MASK ((1 << NET_TX_SOFTIRQ)       | \
534 			   (1 << NET_RX_SOFTIRQ)       | \
535 			   (1 << BLOCK_SOFTIRQ)        | \
536 			   (1 << IRQ_POLL_SOFTIRQ) | \
537 			   (1 << TASKLET_SOFTIRQ))
538 
539 /* map softirq index to softirq name. update 'softirq_to_name' in
540  * kernel/softirq.c when adding a new softirq.
541  */
542 extern const char * const softirq_to_name[NR_SOFTIRQS];
543 
544 /* softirq mask and active fields moved to irq_cpustat_t in
545  * asm/hardirq.h to get better cache usage.  KAO
546  */
547 
548 struct softirq_action
549 {
550 	void	(*action)(struct softirq_action *);
551 };
552 
553 asmlinkage void do_softirq(void);
554 asmlinkage void __do_softirq(void);
555 
556 extern void open_softirq(int nr, void (*action)(struct softirq_action *));
557 extern void softirq_init(void);
558 extern void __raise_softirq_irqoff(unsigned int nr);
559 
560 extern void raise_softirq_irqoff(unsigned int nr);
561 extern void raise_softirq(unsigned int nr);
562 
563 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
564 DECLARE_PER_CPU(__u32, active_softirqs);
565 
this_cpu_ksoftirqd(void)566 static inline struct task_struct *this_cpu_ksoftirqd(void)
567 {
568 	return this_cpu_read(ksoftirqd);
569 }
570 
571 /* Tasklets --- multithreaded analogue of BHs.
572 
573    This API is deprecated. Please consider using threaded IRQs instead:
574    https://lore.kernel.org/lkml/20200716081538.2sivhkj4hcyrusem@linutronix.de
575 
576    Main feature differing them of generic softirqs: tasklet
577    is running only on one CPU simultaneously.
578 
579    Main feature differing them of BHs: different tasklets
580    may be run simultaneously on different CPUs.
581 
582    Properties:
583    * If tasklet_schedule() is called, then tasklet is guaranteed
584      to be executed on some cpu at least once after this.
585    * If the tasklet is already scheduled, but its execution is still not
586      started, it will be executed only once.
587    * If this tasklet is already running on another CPU (or schedule is called
588      from tasklet itself), it is rescheduled for later.
589    * Tasklet is strictly serialized wrt itself, but not
590      wrt another tasklets. If client needs some intertask synchronization,
591      he makes it with spinlocks.
592  */
593 
594 struct tasklet_struct
595 {
596 	struct tasklet_struct *next;
597 	unsigned long state;
598 	atomic_t count;
599 	bool use_callback;
600 	union {
601 		void (*func)(unsigned long data);
602 		void (*callback)(struct tasklet_struct *t);
603 	};
604 	unsigned long data;
605 };
606 
607 #define DECLARE_TASKLET(name, _callback)		\
608 struct tasklet_struct name = {				\
609 	.count = ATOMIC_INIT(0),			\
610 	.callback = _callback,				\
611 	.use_callback = true,				\
612 }
613 
614 #define DECLARE_TASKLET_DISABLED(name, _callback)	\
615 struct tasklet_struct name = {				\
616 	.count = ATOMIC_INIT(1),			\
617 	.callback = _callback,				\
618 	.use_callback = true,				\
619 }
620 
621 #define from_tasklet(var, callback_tasklet, tasklet_fieldname)	\
622 	container_of(callback_tasklet, typeof(*var), tasklet_fieldname)
623 
624 #define DECLARE_TASKLET_OLD(name, _func)		\
625 struct tasklet_struct name = {				\
626 	.count = ATOMIC_INIT(0),			\
627 	.func = _func,					\
628 }
629 
630 #define DECLARE_TASKLET_DISABLED_OLD(name, _func)	\
631 struct tasklet_struct name = {				\
632 	.count = ATOMIC_INIT(1),			\
633 	.func = _func,					\
634 }
635 
636 enum
637 {
638 	TASKLET_STATE_SCHED,	/* Tasklet is scheduled for execution */
639 	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
640 };
641 
642 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
tasklet_trylock(struct tasklet_struct * t)643 static inline int tasklet_trylock(struct tasklet_struct *t)
644 {
645 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
646 }
647 
648 void tasklet_unlock(struct tasklet_struct *t);
649 void tasklet_unlock_wait(struct tasklet_struct *t);
650 void tasklet_unlock_spin_wait(struct tasklet_struct *t);
651 
652 #else
tasklet_trylock(struct tasklet_struct * t)653 static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }
tasklet_unlock(struct tasklet_struct * t)654 static inline void tasklet_unlock(struct tasklet_struct *t) { }
tasklet_unlock_wait(struct tasklet_struct * t)655 static inline void tasklet_unlock_wait(struct tasklet_struct *t) { }
tasklet_unlock_spin_wait(struct tasklet_struct * t)656 static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t) { }
657 #endif
658 
659 extern void __tasklet_schedule(struct tasklet_struct *t);
660 
tasklet_schedule(struct tasklet_struct * t)661 static inline void tasklet_schedule(struct tasklet_struct *t)
662 {
663 	if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
664 		__tasklet_schedule(t);
665 }
666 
667 extern void __tasklet_hi_schedule(struct tasklet_struct *t);
668 
tasklet_hi_schedule(struct tasklet_struct * t)669 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
670 {
671 	if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
672 		__tasklet_hi_schedule(t);
673 }
674 
tasklet_disable_nosync(struct tasklet_struct * t)675 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
676 {
677 	atomic_inc(&t->count);
678 	smp_mb__after_atomic();
679 }
680 
681 /*
682  * Do not use in new code. Disabling tasklets from atomic contexts is
683  * error prone and should be avoided.
684  */
tasklet_disable_in_atomic(struct tasklet_struct * t)685 static inline void tasklet_disable_in_atomic(struct tasklet_struct *t)
686 {
687 	tasklet_disable_nosync(t);
688 	tasklet_unlock_spin_wait(t);
689 	smp_mb();
690 }
691 
tasklet_disable(struct tasklet_struct * t)692 static inline void tasklet_disable(struct tasklet_struct *t)
693 {
694 	tasklet_disable_nosync(t);
695 	tasklet_unlock_wait(t);
696 	smp_mb();
697 }
698 
tasklet_enable(struct tasklet_struct * t)699 static inline void tasklet_enable(struct tasklet_struct *t)
700 {
701 	smp_mb__before_atomic();
702 	atomic_dec(&t->count);
703 }
704 
705 extern void tasklet_kill(struct tasklet_struct *t);
706 extern void tasklet_init(struct tasklet_struct *t,
707 			 void (*func)(unsigned long), unsigned long data);
708 extern void tasklet_setup(struct tasklet_struct *t,
709 			  void (*callback)(struct tasklet_struct *));
710 
711 /*
712  * Autoprobing for irqs:
713  *
714  * probe_irq_on() and probe_irq_off() provide robust primitives
715  * for accurate IRQ probing during kernel initialization.  They are
716  * reasonably simple to use, are not "fooled" by spurious interrupts,
717  * and, unlike other attempts at IRQ probing, they do not get hung on
718  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
719  *
720  * For reasonably foolproof probing, use them as follows:
721  *
722  * 1. clear and/or mask the device's internal interrupt.
723  * 2. sti();
724  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
725  * 4. enable the device and cause it to trigger an interrupt.
726  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
727  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
728  * 7. service the device to clear its pending interrupt.
729  * 8. loop again if paranoia is required.
730  *
731  * probe_irq_on() returns a mask of allocated irq's.
732  *
733  * probe_irq_off() takes the mask as a parameter,
734  * and returns the irq number which occurred,
735  * or zero if none occurred, or a negative irq number
736  * if more than one irq occurred.
737  */
738 
739 #if !defined(CONFIG_GENERIC_IRQ_PROBE)
probe_irq_on(void)740 static inline unsigned long probe_irq_on(void)
741 {
742 	return 0;
743 }
probe_irq_off(unsigned long val)744 static inline int probe_irq_off(unsigned long val)
745 {
746 	return 0;
747 }
probe_irq_mask(unsigned long val)748 static inline unsigned int probe_irq_mask(unsigned long val)
749 {
750 	return 0;
751 }
752 #else
753 extern unsigned long probe_irq_on(void);	/* returns 0 on failure */
754 extern int probe_irq_off(unsigned long);	/* returns 0 or negative on failure */
755 extern unsigned int probe_irq_mask(unsigned long);	/* returns mask of ISA interrupts */
756 #endif
757 
758 #ifdef CONFIG_PROC_FS
759 /* Initialize /proc/irq/ */
760 extern void init_irq_proc(void);
761 #else
init_irq_proc(void)762 static inline void init_irq_proc(void)
763 {
764 }
765 #endif
766 
767 #ifdef CONFIG_IRQ_TIMINGS
768 void irq_timings_enable(void);
769 void irq_timings_disable(void);
770 u64 irq_timings_next_event(u64 now);
771 #endif
772 
773 struct seq_file;
774 int show_interrupts(struct seq_file *p, void *v);
775 int arch_show_interrupts(struct seq_file *p, int prec);
776 
777 extern int early_irq_init(void);
778 extern int arch_probe_nr_irqs(void);
779 extern int arch_early_irq_init(void);
780 
781 /*
782  * We want to know which function is an entrypoint of a hardirq or a softirq.
783  */
784 #ifndef __irq_entry
785 # define __irq_entry	 __section(".irqentry.text")
786 #endif
787 
788 #define __softirq_entry  __section(".softirqentry.text")
789 
790 #endif
791