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1#ifndef _ASM_GENERIC_PERCPU_H_
2#define _ASM_GENERIC_PERCPU_H_
3
4#include <linux/compiler.h>
5#include <linux/threads.h>
6#include <linux/percpu-defs.h>
7
8#ifdef CONFIG_SMP
9
10/*
11 * per_cpu_offset() is the offset that has to be added to a
12 * percpu variable to get to the instance for a certain processor.
13 *
14 * Most arches use the __per_cpu_offset array for those offsets but
15 * some arches have their own ways of determining the offset (x86_64, s390).
16 */
17#ifndef __per_cpu_offset
18extern unsigned long __per_cpu_offset[NR_CPUS];
19
20#define per_cpu_offset(x) (__per_cpu_offset[x])
21#endif
22
23/*
24 * Determine the offset for the currently active processor.
25 * An arch may define __my_cpu_offset to provide a more effective
26 * means of obtaining the offset to the per cpu variables of the
27 * current processor.
28 */
29#ifndef __my_cpu_offset
30#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
31#endif
32#ifdef CONFIG_DEBUG_PREEMPT
33#define my_cpu_offset per_cpu_offset(smp_processor_id())
34#else
35#define my_cpu_offset __my_cpu_offset
36#endif
37
38/*
39 * Add a offset to a pointer but keep the pointer as is.
40 *
41 * Only S390 provides its own means of moving the pointer.
42 */
43#ifndef SHIFT_PERCPU_PTR
44#define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset))
45#endif
46
47/*
48 * A percpu variable may point to a discarded regions. The following are
49 * established ways to produce a usable pointer from the percpu variable
50 * offset.
51 */
52#define per_cpu(var, cpu) \
53 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu)))
54#define __get_cpu_var(var) \
55 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset))
56#define __raw_get_cpu_var(var) \
57 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset))
58
59#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
60#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
61
62
63#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
64extern void setup_per_cpu_areas(void);
65#endif
66
67#else /* ! SMP */
68
69#define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var)))
70#define __get_cpu_var(var) per_cpu_var(var)
71#define __raw_get_cpu_var(var) per_cpu_var(var)
72#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
73#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
74
75#endif /* SMP */
76
77#ifndef PER_CPU_BASE_SECTION
78#ifdef CONFIG_SMP
79#define PER_CPU_BASE_SECTION ".data.percpu"
80#else
81#define PER_CPU_BASE_SECTION ".data"
82#endif
83#endif
84
85#ifdef CONFIG_SMP
86
87#ifdef MODULE
88#define PER_CPU_SHARED_ALIGNED_SECTION ""
89#define PER_CPU_ALIGNED_SECTION ""
90#else
91#define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned"
92#define PER_CPU_ALIGNED_SECTION ".shared_aligned"
93#endif
94#define PER_CPU_FIRST_SECTION ".first"
95
96#else
97
98#define PER_CPU_SHARED_ALIGNED_SECTION ""
99#define PER_CPU_ALIGNED_SECTION ".shared_aligned"
100#define PER_CPU_FIRST_SECTION ""
101
102#endif
103
104#ifndef PER_CPU_ATTRIBUTES
105#define PER_CPU_ATTRIBUTES
106#endif
107
108#ifndef PER_CPU_DEF_ATTRIBUTES
109#define PER_CPU_DEF_ATTRIBUTES
110#endif
111
112#endif /* _ASM_GENERIC_PERCPU_H_ */