1 #ifndef __LINUX_PERCPU_H
2 #define __LINUX_PERCPU_H
4 #include <linux/preempt.h>
5 #include <linux/slab.h> /* For kmalloc() */
7 #include <linux/cpumask.h>
10 #include <asm/percpu.h>
12 /* enough to cover all DEFINE_PER_CPUs in modules */
14 #define PERCPU_MODULE_RESERVE (8 << 10)
16 #define PERCPU_MODULE_RESERVE 0
19 #ifndef PERCPU_ENOUGH_ROOM
20 #define PERCPU_ENOUGH_ROOM \
21 (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \
22 PERCPU_MODULE_RESERVE)
26 * Must be an lvalue. Since @var must be a simple identifier,
27 * we force a syntax error here if it isn't.
29 #define get_cpu_var(var) (*({ \
31 &__get_cpu_var(var); }))
33 #define put_cpu_var(var) do { \
40 /* minimum unit size, also is the maximum supported allocation size */
41 #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10)
44 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
45 * back on the first chunk for dynamic percpu allocation if arch is
46 * manually allocating and mapping it for faster access (as a part of
47 * large page mapping for example).
49 * The following values give between one and two pages of free space
50 * after typical minimal boot (2-way SMP, single disk and NIC) with
51 * both defconfig and a distro config on x86_64 and 32. More
52 * intelligent way to determine this would be nice.
54 #if BITS_PER_LONG > 32
55 #define PERCPU_DYNAMIC_RESERVE (20 << 10)
57 #define PERCPU_DYNAMIC_RESERVE (12 << 10)
60 extern void *pcpu_base_addr;
61 extern const unsigned long *pcpu_unit_offsets;
63 struct pcpu_group_info {
64 int nr_units; /* aligned # of units */
65 unsigned long base_offset; /* base address offset */
66 unsigned int *cpu_map; /* unit->cpu map, empty
67 * entries contain NR_CPUS */
70 struct pcpu_alloc_info {
77 size_t __ai_size; /* internal, don't use */
78 int nr_groups; /* 0 if grouping unnecessary */
79 struct pcpu_group_info groups[];
89 extern const char *pcpu_fc_names[PCPU_FC_NR];
91 extern enum pcpu_fc pcpu_chosen_fc;
93 typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
95 typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
96 typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
97 typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
99 extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
101 extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
103 extern struct pcpu_alloc_info * __init pcpu_build_alloc_info(
104 size_t reserved_size, ssize_t dyn_size,
106 pcpu_fc_cpu_distance_fn_t cpu_distance_fn);
108 extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
111 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
112 extern int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
114 pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
115 pcpu_fc_alloc_fn_t alloc_fn,
116 pcpu_fc_free_fn_t free_fn);
119 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
120 extern int __init pcpu_page_first_chunk(size_t reserved_size,
121 pcpu_fc_alloc_fn_t alloc_fn,
122 pcpu_fc_free_fn_t free_fn,
123 pcpu_fc_populate_pte_fn_t populate_pte_fn);
127 * Use this to get to a cpu's version of the per-cpu object
128 * dynamically allocated. Non-atomic access to the current CPU's
129 * version should probably be combined with get_cpu()/put_cpu().
131 #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
133 extern void *__alloc_reserved_percpu(size_t size, size_t align);
134 extern void *__alloc_percpu(size_t size, size_t align);
135 extern void free_percpu(void *__pdata);
137 #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
138 extern void __init setup_per_cpu_areas(void);
141 #else /* CONFIG_SMP */
143 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
145 static inline void *__alloc_percpu(size_t size, size_t align)
148 * Can't easily make larger alignment work with kmalloc. WARN
149 * on it. Larger alignment should only be used for module
150 * percpu sections on SMP for which this path isn't used.
152 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
153 return kzalloc(size, GFP_KERNEL);
156 static inline void free_percpu(void *p)
161 static inline void __init setup_per_cpu_areas(void) { }
163 static inline void *pcpu_lpage_remapped(void *kaddr)
168 #endif /* CONFIG_SMP */
170 #define alloc_percpu(type) \
171 (typeof(type) *)__alloc_percpu(sizeof(type), __alignof__(type))
174 * Optional methods for optimized non-lvalue per-cpu variable access.
176 * @var can be a percpu variable or a field of it and its size should
177 * equal char, int or long. percpu_read() evaluates to a lvalue and
178 * all others to void.
180 * These operations are guaranteed to be atomic w.r.t. preemption.
181 * The generic versions use plain get/put_cpu_var(). Archs are
182 * encouraged to implement single-instruction alternatives which don't
183 * require preemption protection.
186 # define percpu_read(var) \
188 typeof(var) *pr_ptr__ = &(var); \
189 typeof(var) pr_ret__; \
190 pr_ret__ = get_cpu_var(*pr_ptr__); \
191 put_cpu_var(*pr_ptr__); \
196 #define __percpu_generic_to_op(var, val, op) \
198 typeof(var) *pgto_ptr__ = &(var); \
199 get_cpu_var(*pgto_ptr__) op val; \
200 put_cpu_var(*pgto_ptr__); \
204 # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
208 # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
212 # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
216 # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
220 # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
224 # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
228 * Branching function to split up a function into a set of functions that
229 * are called for different scalar sizes of the objects handled.
232 extern void __bad_size_call_parameter(void);
234 #define __pcpu_size_call_return(stem, variable) \
235 ({ typeof(variable) pscr_ret__; \
236 switch(sizeof(variable)) { \
237 case 1: pscr_ret__ = stem##1(variable);break; \
238 case 2: pscr_ret__ = stem##2(variable);break; \
239 case 4: pscr_ret__ = stem##4(variable);break; \
240 case 8: pscr_ret__ = stem##8(variable);break; \
242 __bad_size_call_parameter();break; \
247 #define __pcpu_size_call(stem, variable, ...) \
249 switch(sizeof(variable)) { \
250 case 1: stem##1(variable, __VA_ARGS__);break; \
251 case 2: stem##2(variable, __VA_ARGS__);break; \
252 case 4: stem##4(variable, __VA_ARGS__);break; \
253 case 8: stem##8(variable, __VA_ARGS__);break; \
255 __bad_size_call_parameter();break; \
260 * Optimized manipulation for memory allocated through the per cpu
261 * allocator or for addresses of per cpu variables.
263 * These operation guarantee exclusivity of access for other operations
264 * on the *same* processor. The assumption is that per cpu data is only
265 * accessed by a single processor instance (the current one).
267 * The first group is used for accesses that must be done in a
268 * preemption safe way since we know that the context is not preempt
269 * safe. Interrupts may occur. If the interrupt modifies the variable
270 * too then RMW actions will not be reliable.
272 * The arch code can provide optimized functions in two ways:
274 * 1. Override the function completely. F.e. define this_cpu_add().
275 * The arch must then ensure that the various scalar format passed
276 * are handled correctly.
278 * 2. Provide functions for certain scalar sizes. F.e. provide
279 * this_cpu_add_2() to provide per cpu atomic operations for 2 byte
280 * sized RMW actions. If arch code does not provide operations for
281 * a scalar size then the fallback in the generic code will be
285 #define _this_cpu_generic_read(pcp) \
286 ({ typeof(pcp) ret__; \
288 ret__ = *this_cpu_ptr(&(pcp)); \
293 #ifndef this_cpu_read
294 # ifndef this_cpu_read_1
295 # define this_cpu_read_1(pcp) _this_cpu_generic_read(pcp)
297 # ifndef this_cpu_read_2
298 # define this_cpu_read_2(pcp) _this_cpu_generic_read(pcp)
300 # ifndef this_cpu_read_4
301 # define this_cpu_read_4(pcp) _this_cpu_generic_read(pcp)
303 # ifndef this_cpu_read_8
304 # define this_cpu_read_8(pcp) _this_cpu_generic_read(pcp)
306 # define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, (pcp))
309 #define _this_cpu_generic_to_op(pcp, val, op) \
312 *__this_cpu_ptr(&(pcp)) op val; \
316 #ifndef this_cpu_write
317 # ifndef this_cpu_write_1
318 # define this_cpu_write_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
320 # ifndef this_cpu_write_2
321 # define this_cpu_write_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
323 # ifndef this_cpu_write_4
324 # define this_cpu_write_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
326 # ifndef this_cpu_write_8
327 # define this_cpu_write_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
329 # define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, (pcp), (val))
333 # ifndef this_cpu_add_1
334 # define this_cpu_add_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
336 # ifndef this_cpu_add_2
337 # define this_cpu_add_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
339 # ifndef this_cpu_add_4
340 # define this_cpu_add_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
342 # ifndef this_cpu_add_8
343 # define this_cpu_add_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
345 # define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, (pcp), (val))
349 # define this_cpu_sub(pcp, val) this_cpu_add((pcp), -(val))
353 # define this_cpu_inc(pcp) this_cpu_add((pcp), 1)
357 # define this_cpu_dec(pcp) this_cpu_sub((pcp), 1)
361 # ifndef this_cpu_and_1
362 # define this_cpu_and_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
364 # ifndef this_cpu_and_2
365 # define this_cpu_and_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
367 # ifndef this_cpu_and_4
368 # define this_cpu_and_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
370 # ifndef this_cpu_and_8
371 # define this_cpu_and_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
373 # define this_cpu_and(pcp, val) __pcpu_size_call(this_cpu_and_, (pcp), (val))
377 # ifndef this_cpu_or_1
378 # define this_cpu_or_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
380 # ifndef this_cpu_or_2
381 # define this_cpu_or_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
383 # ifndef this_cpu_or_4
384 # define this_cpu_or_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
386 # ifndef this_cpu_or_8
387 # define this_cpu_or_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
389 # define this_cpu_or(pcp, val) __pcpu_size_call(this_cpu_or_, (pcp), (val))
393 # ifndef this_cpu_xor_1
394 # define this_cpu_xor_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
396 # ifndef this_cpu_xor_2
397 # define this_cpu_xor_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
399 # ifndef this_cpu_xor_4
400 # define this_cpu_xor_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
402 # ifndef this_cpu_xor_8
403 # define this_cpu_xor_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
405 # define this_cpu_xor(pcp, val) __pcpu_size_call(this_cpu_or_, (pcp), (val))
409 * Generic percpu operations that do not require preemption handling.
410 * Either we do not care about races or the caller has the
411 * responsibility of handling preemptions issues. Arch code can still
412 * override these instructions since the arch per cpu code may be more
413 * efficient and may actually get race freeness for free (that is the
414 * case for x86 for example).
416 * If there is no other protection through preempt disable and/or
417 * disabling interupts then one of these RMW operations can show unexpected
418 * behavior because the execution thread was rescheduled on another processor
419 * or an interrupt occurred and the same percpu variable was modified from
420 * the interrupt context.
422 #ifndef __this_cpu_read
423 # ifndef __this_cpu_read_1
424 # define __this_cpu_read_1(pcp) (*__this_cpu_ptr(&(pcp)))
426 # ifndef __this_cpu_read_2
427 # define __this_cpu_read_2(pcp) (*__this_cpu_ptr(&(pcp)))
429 # ifndef __this_cpu_read_4
430 # define __this_cpu_read_4(pcp) (*__this_cpu_ptr(&(pcp)))
432 # ifndef __this_cpu_read_8
433 # define __this_cpu_read_8(pcp) (*__this_cpu_ptr(&(pcp)))
435 # define __this_cpu_read(pcp) __pcpu_size_call_return(__this_cpu_read_, (pcp))
438 #define __this_cpu_generic_to_op(pcp, val, op) \
440 *__this_cpu_ptr(&(pcp)) op val; \
443 #ifndef __this_cpu_write
444 # ifndef __this_cpu_write_1
445 # define __this_cpu_write_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
447 # ifndef __this_cpu_write_2
448 # define __this_cpu_write_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
450 # ifndef __this_cpu_write_4
451 # define __this_cpu_write_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
453 # ifndef __this_cpu_write_8
454 # define __this_cpu_write_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
456 # define __this_cpu_write(pcp, val) __pcpu_size_call(__this_cpu_write_, (pcp), (val))
459 #ifndef __this_cpu_add
460 # ifndef __this_cpu_add_1
461 # define __this_cpu_add_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
463 # ifndef __this_cpu_add_2
464 # define __this_cpu_add_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
466 # ifndef __this_cpu_add_4
467 # define __this_cpu_add_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
469 # ifndef __this_cpu_add_8
470 # define __this_cpu_add_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
472 # define __this_cpu_add(pcp, val) __pcpu_size_call(__this_cpu_add_, (pcp), (val))
475 #ifndef __this_cpu_sub
476 # define __this_cpu_sub(pcp, val) __this_cpu_add((pcp), -(val))
479 #ifndef __this_cpu_inc
480 # define __this_cpu_inc(pcp) __this_cpu_add((pcp), 1)
483 #ifndef __this_cpu_dec
484 # define __this_cpu_dec(pcp) __this_cpu_sub((pcp), 1)
487 #ifndef __this_cpu_and
488 # ifndef __this_cpu_and_1
489 # define __this_cpu_and_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
491 # ifndef __this_cpu_and_2
492 # define __this_cpu_and_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
494 # ifndef __this_cpu_and_4
495 # define __this_cpu_and_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
497 # ifndef __this_cpu_and_8
498 # define __this_cpu_and_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
500 # define __this_cpu_and(pcp, val) __pcpu_size_call(__this_cpu_and_, (pcp), (val))
503 #ifndef __this_cpu_or
504 # ifndef __this_cpu_or_1
505 # define __this_cpu_or_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
507 # ifndef __this_cpu_or_2
508 # define __this_cpu_or_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
510 # ifndef __this_cpu_or_4
511 # define __this_cpu_or_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
513 # ifndef __this_cpu_or_8
514 # define __this_cpu_or_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
516 # define __this_cpu_or(pcp, val) __pcpu_size_call(__this_cpu_or_, (pcp), (val))
519 #ifndef __this_cpu_xor
520 # ifndef __this_cpu_xor_1
521 # define __this_cpu_xor_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
523 # ifndef __this_cpu_xor_2
524 # define __this_cpu_xor_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
526 # ifndef __this_cpu_xor_4
527 # define __this_cpu_xor_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
529 # ifndef __this_cpu_xor_8
530 # define __this_cpu_xor_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
532 # define __this_cpu_xor(pcp, val) __pcpu_size_call(__this_cpu_xor_, (pcp), (val))
536 * IRQ safe versions of the per cpu RMW operations. Note that these operations
537 * are *not* safe against modification of the same variable from another
538 * processors (which one gets when using regular atomic operations)
539 . They are guaranteed to be atomic vs. local interrupts and
542 #define irqsafe_cpu_generic_to_op(pcp, val, op) \
544 unsigned long flags; \
545 local_irq_save(flags); \
546 *__this_cpu_ptr(&(pcp)) op val; \
547 local_irq_restore(flags); \
550 #ifndef irqsafe_cpu_add
551 # ifndef irqsafe_cpu_add_1
552 # define irqsafe_cpu_add_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
554 # ifndef irqsafe_cpu_add_2
555 # define irqsafe_cpu_add_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
557 # ifndef irqsafe_cpu_add_4
558 # define irqsafe_cpu_add_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
560 # ifndef irqsafe_cpu_add_8
561 # define irqsafe_cpu_add_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
563 # define irqsafe_cpu_add(pcp, val) __pcpu_size_call(irqsafe_cpu_add_, (pcp), (val))
566 #ifndef irqsafe_cpu_sub
567 # define irqsafe_cpu_sub(pcp, val) irqsafe_cpu_add((pcp), -(val))
570 #ifndef irqsafe_cpu_inc
571 # define irqsafe_cpu_inc(pcp) irqsafe_cpu_add((pcp), 1)
574 #ifndef irqsafe_cpu_dec
575 # define irqsafe_cpu_dec(pcp) irqsafe_cpu_sub((pcp), 1)
578 #ifndef irqsafe_cpu_and
579 # ifndef irqsafe_cpu_and_1
580 # define irqsafe_cpu_and_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
582 # ifndef irqsafe_cpu_and_2
583 # define irqsafe_cpu_and_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
585 # ifndef irqsafe_cpu_and_4
586 # define irqsafe_cpu_and_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
588 # ifndef irqsafe_cpu_and_8
589 # define irqsafe_cpu_and_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
591 # define irqsafe_cpu_and(pcp, val) __pcpu_size_call(irqsafe_cpu_and_, (val))
594 #ifndef irqsafe_cpu_or
595 # ifndef irqsafe_cpu_or_1
596 # define irqsafe_cpu_or_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
598 # ifndef irqsafe_cpu_or_2
599 # define irqsafe_cpu_or_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
601 # ifndef irqsafe_cpu_or_4
602 # define irqsafe_cpu_or_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
604 # ifndef irqsafe_cpu_or_8
605 # define irqsafe_cpu_or_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
607 # define irqsafe_cpu_or(pcp, val) __pcpu_size_call(irqsafe_cpu_or_, (val))
610 #ifndef irqsafe_cpu_xor
611 # ifndef irqsafe_cpu_xor_1
612 # define irqsafe_cpu_xor_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
614 # ifndef irqsafe_cpu_xor_2
615 # define irqsafe_cpu_xor_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
617 # ifndef irqsafe_cpu_xor_4
618 # define irqsafe_cpu_xor_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
620 # ifndef irqsafe_cpu_xor_8
621 # define irqsafe_cpu_xor_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
623 # define irqsafe_cpu_xor(pcp, val) __pcpu_size_call(irqsafe_cpu_xor_, (val))
626 #endif /* __LINUX_PERCPU_H */