Linux kernel mirror (for testing)
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linux
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#ifndef PER_CPU_BASE_SECTION
13#ifdef CONFIG_SMP
14#define PER_CPU_BASE_SECTION ".data.percpu"
15#else
16#define PER_CPU_BASE_SECTION ".data"
17#endif
18#endif
19
20#ifdef CONFIG_SMP
21
22#ifdef MODULE
23#define PER_CPU_SHARED_ALIGNED_SECTION ""
24#else
25#define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned"
26#endif
27#define PER_CPU_FIRST_SECTION ".first"
28
29#else
30
31#define PER_CPU_SHARED_ALIGNED_SECTION ""
32#define PER_CPU_FIRST_SECTION ""
33
34#endif
35
36#define DEFINE_PER_CPU_SECTION(type, name, section) \
37 __attribute__((__section__(PER_CPU_BASE_SECTION section))) \
38 PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name
39
40#define DEFINE_PER_CPU(type, name) \
41 DEFINE_PER_CPU_SECTION(type, name, "")
42
43#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name) \
44 DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \
45 ____cacheline_aligned_in_smp
46
47#define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \
48 DEFINE_PER_CPU_SECTION(type, name, ".page_aligned")
49
50#define DEFINE_PER_CPU_FIRST(type, name) \
51 DEFINE_PER_CPU_SECTION(type, name, PER_CPU_FIRST_SECTION)
52
53#define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(per_cpu__##var)
54#define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(per_cpu__##var)
55
56/* enough to cover all DEFINE_PER_CPUs in modules */
57#ifdef CONFIG_MODULES
58#define PERCPU_MODULE_RESERVE (8 << 10)
59#else
60#define PERCPU_MODULE_RESERVE 0
61#endif
62
63#ifndef PERCPU_ENOUGH_ROOM
64#define PERCPU_ENOUGH_ROOM \
65 (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \
66 PERCPU_MODULE_RESERVE)
67#endif
68
69/*
70 * Must be an lvalue. Since @var must be a simple identifier,
71 * we force a syntax error here if it isn't.
72 */
73#define get_cpu_var(var) (*({ \
74 extern int simple_identifier_##var(void); \
75 preempt_disable(); \
76 &__get_cpu_var(var); }))
77#define put_cpu_var(var) preempt_enable()
78
79#ifdef CONFIG_SMP
80
81#ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA
82
83/* minimum unit size, also is the maximum supported allocation size */
84#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10)
85
86/*
87 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
88 * back on the first chunk for dynamic percpu allocation if arch is
89 * manually allocating and mapping it for faster access (as a part of
90 * large page mapping for example).
91 *
92 * The following values give between one and two pages of free space
93 * after typical minimal boot (2-way SMP, single disk and NIC) with
94 * both defconfig and a distro config on x86_64 and 32. More
95 * intelligent way to determine this would be nice.
96 */
97#if BITS_PER_LONG > 32
98#define PERCPU_DYNAMIC_RESERVE (20 << 10)
99#else
100#define PERCPU_DYNAMIC_RESERVE (12 << 10)
101#endif
102
103extern void *pcpu_base_addr;
104
105typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno);
106typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr);
107
108extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn,
109 size_t static_size, size_t reserved_size,
110 ssize_t dyn_size, ssize_t unit_size,
111 void *base_addr,
112 pcpu_populate_pte_fn_t populate_pte_fn);
113
114extern ssize_t __init pcpu_embed_first_chunk(
115 size_t static_size, size_t reserved_size,
116 ssize_t dyn_size, ssize_t unit_size);
117
118/*
119 * Use this to get to a cpu's version of the per-cpu object
120 * dynamically allocated. Non-atomic access to the current CPU's
121 * version should probably be combined with get_cpu()/put_cpu().
122 */
123#define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
124
125extern void *__alloc_reserved_percpu(size_t size, size_t align);
126
127#else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
128
129struct percpu_data {
130 void *ptrs[1];
131};
132
133#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
134
135#define per_cpu_ptr(ptr, cpu) \
136({ \
137 struct percpu_data *__p = __percpu_disguise(ptr); \
138 (__typeof__(ptr))__p->ptrs[(cpu)]; \
139})
140
141#endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
142
143extern void *__alloc_percpu(size_t size, size_t align);
144extern void free_percpu(void *__pdata);
145
146#else /* CONFIG_SMP */
147
148#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
149
150static inline void *__alloc_percpu(size_t size, size_t align)
151{
152 /*
153 * Can't easily make larger alignment work with kmalloc. WARN
154 * on it. Larger alignment should only be used for module
155 * percpu sections on SMP for which this path isn't used.
156 */
157 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
158 return kzalloc(size, GFP_KERNEL);
159}
160
161static inline void free_percpu(void *p)
162{
163 kfree(p);
164}
165
166#endif /* CONFIG_SMP */
167
168#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
169 __alignof__(type))
170
171#endif /* __LINUX_PERCPU_H */