aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/percpu.h
blob: 5095b834a6fb52f1f746257805f34cdabf186528 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
#ifndef __LINUX_PERCPU_H
#define __LINUX_PERCPU_H

#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/pfn.h>
#include <linux/init.h>

#include <asm/percpu.h>

/* enough to cover all DEFINE_PER_CPUs in modules */
#ifdef CONFIG_MODULES
#define PERCPU_MODULE_RESERVE		(8 << 10)
#else
#define PERCPU_MODULE_RESERVE		0
#endif

#ifndef PERCPU_ENOUGH_ROOM
#define PERCPU_ENOUGH_ROOM						\
	(ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) +	\
	 PERCPU_MODULE_RESERVE)
#endif

/*
 * Must be an lvalue. Since @var must be a simple identifier,
 * we force a syntax error here if it isn't.
 */
#define get_cpu_var(var) (*({				\
	preempt_disable();				\
	&__get_cpu_var(var); }))

/*
 * The weird & is necessary because sparse considers (void)(var) to be
 * a direct dereference of percpu variable (var).
 */
#define put_cpu_var(var) do {				\
	(void)&(var);					\
	preempt_enable();				\
} while (0)

#define get_cpu_ptr(var) ({				\
	preempt_disable();				\
	this_cpu_ptr(var); })

#define put_cpu_ptr(var) do {				\
	(void)(var);					\
	preempt_enable();				\
} while (0)

/* minimum unit size, also is the maximum supported allocation size */
#define PCPU_MIN_UNIT_SIZE		PFN_ALIGN(32 << 10)

/*
 * Percpu allocator can serve percpu allocations before slab is
 * initialized which allows slab to depend on the percpu allocator.
 * The following two parameters decide how much resource to
 * preallocate for this.  Keep PERCPU_DYNAMIC_RESERVE equal to or
 * larger than PERCPU_DYNAMIC_EARLY_SIZE.
 */
#define PERCPU_DYNAMIC_EARLY_SLOTS	128
#define PERCPU_DYNAMIC_EARLY_SIZE	(12 << 10)

/*
 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
 * back on the first chunk for dynamic percpu allocation if arch is
 * manually allocating and mapping it for faster access (as a part of
 * large page mapping for example).
 *
 * The following values give between one and two pages of free space
 * after typical minimal boot (2-way SMP, single disk and NIC) with
 * both defconfig and a distro config on x86_64 and 32.  More
 * intelligent way to determine this would be nice.
 */
#if BITS_PER_LONG > 32
#define PERCPU_DYNAMIC_RESERVE		(20 << 10)
#else
#define PERCPU_DYNAMIC_RESERVE		(12 << 10)
#endif

extern void *pcpu_base_addr;
extern const unsigned long *pcpu_unit_offsets;

struct pcpu_group_info {
	int			nr_units;	/* aligned # of units */
	unsigned long		base_offset;	/* base address offset */
	unsigned int		*cpu_map;	/* unit->cpu map, empty
						 * entries contain NR_CPUS */
};

struct pcpu_alloc_info {
	size_t			static_size;
	size_t			reserved_size;
	size_t			dyn_size;
	size_t			unit_size;
	size_t			atom_size;
	size_t			alloc_size;
	size_t			__ai_size;	/* internal, don't use */
	int			nr_groups;	/* 0 if grouping unnecessary */
	struct pcpu_group_info	groups[];
};

enum pcpu_fc {
	PCPU_FC_AUTO,
	PCPU_FC_EMBED,
	PCPU_FC_PAGE,

	PCPU_FC_NR,
};
extern const char *pcpu_fc_names[PCPU_FC_NR];

extern enum pcpu_fc pcpu_chosen_fc;

typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
				     size_t align);
typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);

extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
							     int nr_units);
extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);

extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
					 void *base_addr);

#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
				size_t atom_size,
				pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
				pcpu_fc_alloc_fn_t alloc_fn,
				pcpu_fc_free_fn_t free_fn);
#endif

#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
extern int __init pcpu_page_first_chunk(size_t reserved_size,
				pcpu_fc_alloc_fn_t alloc_fn,
				pcpu_fc_free_fn_t free_fn,
				pcpu_fc_populate_pte_fn_t populate_pte_fn);
#endif

/*
 * Use this to get to a cpu's version of the per-cpu object
 * dynamically allocated. Non-atomic access to the current CPU's
 * version should probably be combined with get_cpu()/put_cpu().
 */
#ifdef CONFIG_SMP
#define per_cpu_ptr(ptr, cpu)	SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
#else
#define per_cpu_ptr(ptr, cpu)	({ (void)(cpu); VERIFY_PERCPU_PTR((ptr)); })
#endif

extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
extern bool is_kernel_percpu_address(unsigned long addr);

#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
extern void __init setup_per_cpu_areas(void);
#endif
extern void __init percpu_init_late(void);

extern void __percpu *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void __percpu *__pdata);
extern phys_addr_t per_cpu_ptr_to_phys(void *addr);

#define alloc_percpu(type)	\
	(typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type))

/*
 * Optional methods for optimized non-lvalue per-cpu variable access.
 *
 * @var can be a percpu variable or a field of it and its size should
 * equal char, int or long.  percpu_read() evaluates to a lvalue and
 * all others to void.
 *
 * These operations are guaranteed to be atomic w.r.t. preemption.
 * The generic versions use plain get/put_cpu_var().  Archs are
 * encouraged to implement single-instruction alternatives which don't
 * require preemption protection.
 */
#ifndef percpu_read
# define percpu_read(var)						\
  ({									\
	typeof(var) *pr_ptr__ = &(var);					\
	typeof(var) pr_ret__;						\
	pr_ret__ = get_cpu_var(*pr_ptr__);				\
	put_cpu_var(*pr_ptr__);						\
	pr_ret__;							\
  })
#endif

#define __percpu_generic_to_op(var, val, op)				\
do {									\
	typeof(var) *pgto_ptr__ = &(var);				\
	get_cpu_var(*pgto_ptr__) op val;				\
	put_cpu_var(*pgto_ptr__);					\
} while (0)

#ifndef percpu_write
# define percpu_write(var, val)		__percpu_generic_to_op(var, (val), =)
#endif

#ifndef percpu_add
# define percpu_add(var, val)		__percpu_generic_to_op(var, (val), +=)
#endif

#ifndef percpu_sub
# define percpu_sub(var, val)		__percpu_generic_to_op(var, (val), -=)
#endif

#ifndef percpu_and
# define percpu_and(var, val)		__percpu_generic_to_op(var, (val), &=)
#endif

#ifndef percpu_or
# define percpu_or(var, val)		__percpu_generic_to_op(var, (val), |=)
#endif

#ifndef percpu_xor
# define percpu_xor(var, val)		__percpu_generic_to_op(var, (val), ^=)
#endif

/*
 * Branching function to split up a function into a set of functions that
 * are called for different scalar sizes of the objects handled.
 */

extern void __bad_size_call_parameter(void);

#define __pcpu_size_call_return(stem, variable)				\
({	typeof(variable) pscr_ret__;					\
	__verify_pcpu_ptr(&(variable));					\
	switch(sizeof(variable)) {					\
	case 1: pscr_ret__ = stem##1(variable);break;			\
	case 2: pscr_ret__ = stem##2(variable);break;			\
	case 4: pscr_ret__ = stem##4(variable);break;			\
	case 8: pscr_ret__ = stem##8(variable);break;			\
	default:							\
		__bad_size_call_parameter();break;			\
	}								\
	pscr_ret__;							\
})

#define __pcpu_size_call(stem, variable, ...)				\
do {									\
	__verify_pcpu_ptr(&(variable));					\
	switch(sizeof(variable)) {					\
		case 1: stem##1(variable, __VA_ARGS__);break;		\
		case 2: stem##2(variable, __VA_ARGS__);break;		\
		case 4: stem##4(variable, __VA_ARGS__);break;		\
		case 8: stem##8(variable, __VA_ARGS__);break;		\
		default: 						\
			__bad_size_call_parameter();break;		\
	}								\
} while (0)

/*
 * Optimized manipulation for memory allocated through the per cpu
 * allocator or for addresses of per cpu variables.
 *
 * These operation guarantee exclusivity of access for other operations
 * on the *same* processor. The assumption is that per cpu data is only
 * accessed by a single processor instance (the current one).
 *
 * The first group is used for accesses that must be done in a
 * preemption safe way since we know that the context is not preempt
 * safe. Interrupts may occur. If the interrupt modifies the variable
 * too then RMW actions will not be reliable.
 *
 * The arch code can provide optimized functions in two ways:
 *
 * 1. Override the function completely. F.e. define this_cpu_add().
 *    The arch must then ensure that the various scalar format passed
 *    are handled correctly.
 *
 * 2. Provide functions for certain scalar sizes. F.e. provide
 *    this_cpu_add_2() to provide per cpu atomic operations for 2 byte
 *    sized RMW actions. If arch code does not provide operations for
 *    a scalar size then the fallback in the generic code will be
 *    used.
 */

#define _this_cpu_generic_read(pcp)					\
({	typeof(pcp) ret__;						\
	preempt_disable();						\
	ret__ = *this_cpu_ptr(&(pcp));					\
	preempt_enable();						\
	ret__;								\
})

#ifndef this_cpu_read
# ifndef this_cpu_read_1
#  define this_cpu_read_1(pcp)	_this_cpu_generic_read(pcp)
# endif
# ifndef this_cpu_read_2
#  define this_cpu_read_2(pcp)	_this_cpu_generic_read(pcp)
# endif
# ifndef this_cpu_read_4
#  define this_cpu_read_4(pcp)	_this_cpu_generic_read(pcp)
# endif
# ifndef this_cpu_read_8
#  define this_cpu_read_8(pcp)	_this_cpu_generic_read(pcp)
# endif
# define this_cpu_read(pcp)	__pcpu_size_call_return(this_cpu_read_, (pcp))
#endif

#define _this_cpu_generic_to_op(pcp, val, op)				\
do {									\
	preempt_disable();						\
	*__this_cpu_ptr(&(pcp)) op val;					\
	preempt_enable();						\
} while (0)

#ifndef this_cpu_write
# ifndef this_cpu_write_1
#  define this_cpu_write_1(pcp, val)	_this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef this_cpu_write_2
#  define this_cpu_write_2(pcp, val)	_this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef this_cpu_write_4
#  define this_cpu_write_4(pcp, val)	_this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef this_cpu_write_8
#  define this_cpu_write_8(pcp, val)	_this_cpu_generic_to_op((pcp), (val), =)
# endif
# define this_cpu_write(pcp, val)	__pcpu_size_call(this_cpu_write_, (pcp), (val))
#endif

#ifndef this_cpu_add
# ifndef this_cpu_add_1
#  define this_cpu_add_1(pcp, val)	_this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef this_cpu_add_2
#  define this_cpu_add_2(pcp, val)	_this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef this_cpu_add_4
#  define this_cpu_add_4(pcp, val)	_this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef this_cpu_add_8
#  define this_cpu_add_8(pcp, val)	_this_cpu_generic_to_op((pcp), (val), +=)
# endif
# define this_cpu_add(pcp, val)		__pcpu_size_call(this_cpu_add_, (pcp), (val))
#endif

#ifndef this_cpu_sub
# define this_cpu_sub(pcp, val)		this_cpu_add((pcp), -(val))
#endif

#ifndef this_cpu_inc
# define this_cpu_inc(pcp)		this_cpu_add((pcp), 1)
#endif

#ifndef this_cpu_dec
# define this_cpu_dec(pcp)		this_cpu_sub((pcp), 1)
#endif

#ifndef this_cpu_and
# ifndef this_cpu_and_1
#  define this_cpu_and_1(pcp, val)	_this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef this_cpu_and_2
#  define this_cpu_and_2(pcp, val)	_this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef this_cpu_and_4
#  define this_cpu_and_4(pcp, val)	_this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef this_cpu_and_8
#  define this_cpu_and_8(pcp, val)	_this_cpu_generic_to_op((pcp), (val), &=)
# endif
# define this_cpu_and(pcp, val)		__pcpu_size_call(this_cpu_and_, (pcp), (val))
#endif

#ifndef this_cpu_or
# ifndef this_cpu_or_1
#  define this_cpu_or_1(pcp, val)	_this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef this_cpu_or_2
#  define this_cpu_or_2(pcp, val)	_this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef this_cpu_or_4
#  define this_cpu_or_4(pcp, val)	_this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef this_cpu_or_8
#  define this_cpu_or_8(pcp, val)	_this_cpu_generic_to_op((pcp), (val), |=)
# endif
# define this_cpu_or(pcp, val)		__pcpu_size_call(this_cpu_or_, (pcp), (val))
#endif

#ifndef this_cpu_xor
# ifndef this_cpu_xor_1
#  define this_cpu_xor_1(pcp, val)	_this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef this_cpu_xor_2
#  define this_cpu_xor_2(pcp, val)	_this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef this_cpu_xor_4
#  define this_cpu_xor_4(pcp, val)	_this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef this_cpu_xor_8
#  define this_cpu_xor_8(pcp, val)	_this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# define this_cpu_xor(pcp, val)		__pcpu_size_call(this_cpu_or_, (pcp), (val))
#endif

/*
 * Generic percpu operations that do not require preemption handling.
 * Either we do not care about races or the caller has the
 * responsibility of handling preemptions issues. Arch code can still
 * override these instructions since the arch per cpu code may be more
 * efficient and may actually get race freeness for free (that is the
 * case for x86 for example).
 *
 * If there is no other protection through preempt disable and/or
 * disabling interupts then one of these RMW operations can show unexpected
 * behavior because the execution thread was rescheduled on another processor
 * or an interrupt occurred and the same percpu variable was modified from
 * the interrupt context.
 */
#ifndef __this_cpu_read
# ifndef __this_cpu_read_1
#  define __this_cpu_read_1(pcp)	(*__this_cpu_ptr(&(pcp)))
# endif
# ifndef __this_cpu_read_2
#  define __this_cpu_read_2(pcp)	(*__this_cpu_ptr(&(pcp)))
# endif
# ifndef __this_cpu_read_4
#  define __this_cpu_read_4(pcp)	(*__this_cpu_ptr(&(pcp)))
# endif
# ifndef __this_cpu_read_8
#  define __this_cpu_read_8(pcp)	(*__this_cpu_ptr(&(pcp)))
# endif
# define __this_cpu_read(pcp)	__pcpu_size_call_return(__this_cpu_read_, (pcp))
#endif

#define __this_cpu_generic_to_op(pcp, val, op)				\
do {									\
	*__this_cpu_ptr(&(pcp)) op val;					\
} while (0)

#ifndef __this_cpu_write
# ifndef __this_cpu_write_1
#  define __this_cpu_write_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef __this_cpu_write_2
#  define __this_cpu_write_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef __this_cpu_write_4
#  define __this_cpu_write_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef __this_cpu_write_8
#  define __this_cpu_write_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), =)
# endif
# define __this_cpu_write(pcp, val)	__pcpu_size_call(__this_cpu_write_, (pcp), (val))
#endif

#ifndef __this_cpu_add
# ifndef __this_cpu_add_1
#  define __this_cpu_add_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef __this_cpu_add_2
#  define __this_cpu_add_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef __this_cpu_add_4
#  define __this_cpu_add_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef __this_cpu_add_8
#  define __this_cpu_add_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), +=)
# endif
# define __this_cpu_add(pcp, val)	__pcpu_size_call(__this_cpu_add_, (pcp), (val))
#endif

#ifndef __this_cpu_sub
# define __this_cpu_sub(pcp, val)	__this_cpu_add((pcp), -(val))
#endif

#ifndef __this_cpu_inc
# define __this_cpu_inc(pcp)		__this_cpu_add((pcp), 1)
#endif

#ifndef __this_cpu_dec
# define __this_cpu_dec(pcp)		__this_cpu_sub((pcp), 1)
#endif

#ifndef __this_cpu_and
# ifndef __this_cpu_and_1
#  define __this_cpu_and_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef __this_cpu_and_2
#  define __this_cpu_and_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef __this_cpu_and_4
#  define __this_cpu_and_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef __this_cpu_and_8
#  define __this_cpu_and_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), &=)
# endif
# define __this_cpu_and(pcp, val)	__pcpu_size_call(__this_cpu_and_, (pcp), (val))
#endif

#ifndef __this_cpu_or
# ifndef __this_cpu_or_1
#  define __this_cpu_or_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef __this_cpu_or_2
#  define __this_cpu_or_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef __this_cpu_or_4
#  define __this_cpu_or_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef __this_cpu_or_8
#  define __this_cpu_or_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), |=)
# endif
# define __this_cpu_or(pcp, val)	__pcpu_size_call(__this_cpu_or_, (pcp), (val))
#endif

#ifndef __this_cpu_xor
# ifndef __this_cpu_xor_1
#  define __this_cpu_xor_1(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef __this_cpu_xor_2
#  define __this_cpu_xor_2(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef __this_cpu_xor_4
#  define __this_cpu_xor_4(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef __this_cpu_xor_8
#  define __this_cpu_xor_8(pcp, val)	__this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# define __this_cpu_xor(pcp, val)	__pcpu_size_call(__this_cpu_xor_, (pcp), (val))
#endif

/*
 * IRQ safe versions of the per cpu RMW operations. Note that these operations
 * are *not* safe against modification of the same variable from another
 * processors (which one gets when using regular atomic operations)
 . They are guaranteed to be atomic vs. local interrupts and
 * preemption only.
 */
#define irqsafe_cpu_generic_to_op(pcp, val, op)				\
do {									\
	unsigned long flags;						\
	local_irq_save(flags);						\
	*__this_cpu_ptr(&(pcp)) op val;					\
	local_irq_restore(flags);					\
} while (0)

#ifndef irqsafe_cpu_add
# ifndef irqsafe_cpu_add_1
#  define irqsafe_cpu_add_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef irqsafe_cpu_add_2
#  define irqsafe_cpu_add_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef irqsafe_cpu_add_4
#  define irqsafe_cpu_add_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef irqsafe_cpu_add_8
#  define irqsafe_cpu_add_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# define irqsafe_cpu_add(pcp, val) __pcpu_size_call(irqsafe_cpu_add_, (pcp), (val))
#endif

#ifndef irqsafe_cpu_sub
# define irqsafe_cpu_sub(pcp, val)	irqsafe_cpu_add((pcp), -(val))
#endif

#ifndef irqsafe_cpu_inc
# define irqsafe_cpu_inc(pcp)	irqsafe_cpu_add((pcp), 1)
#endif

#ifndef irqsafe_cpu_dec
# define irqsafe_cpu_dec(pcp)	irqsafe_cpu_sub((pcp), 1)
#endif

#ifndef irqsafe_cpu_and
# ifndef irqsafe_cpu_and_1
#  define irqsafe_cpu_and_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef irqsafe_cpu_and_2
#  define irqsafe_cpu_and_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef irqsafe_cpu_and_4
#  define irqsafe_cpu_and_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef irqsafe_cpu_and_8
#  define irqsafe_cpu_and_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# define irqsafe_cpu_and(pcp, val) __pcpu_size_call(irqsafe_cpu_and_, (val))
#endif

#ifndef irqsafe_cpu_or
# ifndef irqsafe_cpu_or_1
#  define irqsafe_cpu_or_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef irqsafe_cpu_or_2
#  define irqsafe_cpu_or_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef irqsafe_cpu_or_4
#  define irqsafe_cpu_or_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef irqsafe_cpu_or_8
#  define irqsafe_cpu_or_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# define irqsafe_cpu_or(pcp, val) __pcpu_size_call(irqsafe_cpu_or_, (val))
#endif

#ifndef irqsafe_cpu_xor
# ifndef irqsafe_cpu_xor_1
#  define irqsafe_cpu_xor_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef irqsafe_cpu_xor_2
#  define irqsafe_cpu_xor_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef irqsafe_cpu_xor_4
#  define irqsafe_cpu_xor_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef irqsafe_cpu_xor_8
#  define irqsafe_cpu_xor_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# define irqsafe_cpu_xor(pcp, val) __pcpu_size_call(irqsafe_cpu_xor_, (val))
#endif

#endif /* __LINUX_PERCPU_H */