Linux kernel mirror (for testing)
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1#ifndef __LINUX_PERCPU_H
2#define __LINUX_PERCPU_H
3
4#include <linux/preempt.h>
5#include <linux/slab.h> /* For kmalloc() */
6#include <linux/smp.h>
7#include <linux/cpumask.h>
8#include <linux/pfn.h>
9
10#include <asm/percpu.h>
11
12/* enough to cover all DEFINE_PER_CPUs in modules */
13#ifdef CONFIG_MODULES
14#define PERCPU_MODULE_RESERVE (8 << 10)
15#else
16#define PERCPU_MODULE_RESERVE 0
17#endif
18
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)
23#endif
24
25/*
26 * Must be an lvalue. Since @var must be a simple identifier,
27 * we force a syntax error here if it isn't.
28 */
29#define get_cpu_var(var) (*({ \
30 extern int simple_identifier_##var(void); \
31 preempt_disable(); \
32 &__get_cpu_var(var); }))
33#define put_cpu_var(var) preempt_enable()
34
35#ifdef CONFIG_SMP
36
37#ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA
38
39/* minimum unit size, also is the maximum supported allocation size */
40#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10)
41
42/*
43 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
44 * back on the first chunk for dynamic percpu allocation if arch is
45 * manually allocating and mapping it for faster access (as a part of
46 * large page mapping for example).
47 *
48 * The following values give between one and two pages of free space
49 * after typical minimal boot (2-way SMP, single disk and NIC) with
50 * both defconfig and a distro config on x86_64 and 32. More
51 * intelligent way to determine this would be nice.
52 */
53#if BITS_PER_LONG > 32
54#define PERCPU_DYNAMIC_RESERVE (20 << 10)
55#else
56#define PERCPU_DYNAMIC_RESERVE (12 << 10)
57#endif
58
59extern void *pcpu_base_addr;
60
61typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno);
62typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr);
63
64extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
65 size_t static_size, size_t reserved_size,
66 ssize_t dyn_size, ssize_t unit_size,
67 void *base_addr,
68 pcpu_populate_pte_fn_t populate_pte_fn);
69
70extern ssize_t __init pcpu_embed_first_chunk(
71 size_t static_size, size_t reserved_size,
72 ssize_t dyn_size, ssize_t unit_size);
73
74/*
75 * Use this to get to a cpu's version of the per-cpu object
76 * dynamically allocated. Non-atomic access to the current CPU's
77 * version should probably be combined with get_cpu()/put_cpu().
78 */
79#define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
80
81extern void *__alloc_reserved_percpu(size_t size, size_t align);
82
83#else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
84
85struct percpu_data {
86 void *ptrs[1];
87};
88
89#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
90
91#define per_cpu_ptr(ptr, cpu) \
92({ \
93 struct percpu_data *__p = __percpu_disguise(ptr); \
94 (__typeof__(ptr))__p->ptrs[(cpu)]; \
95})
96
97#endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
98
99extern void *__alloc_percpu(size_t size, size_t align);
100extern void free_percpu(void *__pdata);
101
102#else /* CONFIG_SMP */
103
104#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
105
106static inline void *__alloc_percpu(size_t size, size_t align)
107{
108 /*
109 * Can't easily make larger alignment work with kmalloc. WARN
110 * on it. Larger alignment should only be used for module
111 * percpu sections on SMP for which this path isn't used.
112 */
113 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
114 return kzalloc(size, GFP_KERNEL);
115}
116
117static inline void free_percpu(void *p)
118{
119 kfree(p);
120}
121
122#endif /* CONFIG_SMP */
123
124#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
125 __alignof__(type))
126
127/*
128 * Optional methods for optimized non-lvalue per-cpu variable access.
129 *
130 * @var can be a percpu variable or a field of it and its size should
131 * equal char, int or long. percpu_read() evaluates to a lvalue and
132 * all others to void.
133 *
134 * These operations are guaranteed to be atomic w.r.t. preemption.
135 * The generic versions use plain get/put_cpu_var(). Archs are
136 * encouraged to implement single-instruction alternatives which don't
137 * require preemption protection.
138 */
139#ifndef percpu_read
140# define percpu_read(var) \
141 ({ \
142 typeof(per_cpu_var(var)) __tmp_var__; \
143 __tmp_var__ = get_cpu_var(var); \
144 put_cpu_var(var); \
145 __tmp_var__; \
146 })
147#endif
148
149#define __percpu_generic_to_op(var, val, op) \
150do { \
151 get_cpu_var(var) op val; \
152 put_cpu_var(var); \
153} while (0)
154
155#ifndef percpu_write
156# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
157#endif
158
159#ifndef percpu_add
160# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
161#endif
162
163#ifndef percpu_sub
164# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
165#endif
166
167#ifndef percpu_and
168# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
169#endif
170
171#ifndef percpu_or
172# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
173#endif
174
175#ifndef percpu_xor
176# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
177#endif
178
179#endif /* __LINUX_PERCPU_H */