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/* pointer disguising messes up the kmemleak objects tracking */
90#ifndef CONFIG_DEBUG_KMEMLEAK
91#define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata)
92#else
93#define __percpu_disguise(pdata) (struct percpu_data *)(pdata)
94#endif
95
96#define per_cpu_ptr(ptr, cpu) \
97({ \
98 struct percpu_data *__p = __percpu_disguise(ptr); \
99 (__typeof__(ptr))__p->ptrs[(cpu)]; \
100})
101
102#endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */
103
104extern void *__alloc_percpu(size_t size, size_t align);
105extern void free_percpu(void *__pdata);
106
107#else /* CONFIG_SMP */
108
109#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); })
110
111static inline void *__alloc_percpu(size_t size, size_t align)
112{
113 /*
114 * Can't easily make larger alignment work with kmalloc. WARN
115 * on it. Larger alignment should only be used for module
116 * percpu sections on SMP for which this path isn't used.
117 */
118 WARN_ON_ONCE(align > SMP_CACHE_BYTES);
119 return kzalloc(size, GFP_KERNEL);
120}
121
122static inline void free_percpu(void *p)
123{
124 kfree(p);
125}
126
127#endif /* CONFIG_SMP */
128
129#define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \
130 __alignof__(type))
131
132/*
133 * Optional methods for optimized non-lvalue per-cpu variable access.
134 *
135 * @var can be a percpu variable or a field of it and its size should
136 * equal char, int or long. percpu_read() evaluates to a lvalue and
137 * all others to void.
138 *
139 * These operations are guaranteed to be atomic w.r.t. preemption.
140 * The generic versions use plain get/put_cpu_var(). Archs are
141 * encouraged to implement single-instruction alternatives which don't
142 * require preemption protection.
143 */
144#ifndef percpu_read
145# define percpu_read(var) \
146 ({ \
147 typeof(per_cpu_var(var)) __tmp_var__; \
148 __tmp_var__ = get_cpu_var(var); \
149 put_cpu_var(var); \
150 __tmp_var__; \
151 })
152#endif
153
154#define __percpu_generic_to_op(var, val, op) \
155do { \
156 get_cpu_var(var) op val; \
157 put_cpu_var(var); \
158} while (0)
159
160#ifndef percpu_write
161# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
162#endif
163
164#ifndef percpu_add
165# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
166#endif
167
168#ifndef percpu_sub
169# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
170#endif
171
172#ifndef percpu_and
173# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
174#endif
175
176#ifndef percpu_or
177# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
178#endif
179
180#ifndef percpu_xor
181# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
182#endif
183
184#endif /* __LINUX_PERCPU_H */