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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/* Weird cast keeps both GCC and sparse happy. */
45#define SHIFT_PERCPU_PTR(__p, __offset) ({ \
46 __verify_pcpu_ptr((__p)); \
47 RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
48})
49#endif
50
51/*
52 * A percpu variable may point to a discarded regions. The following are
53 * established ways to produce a usable pointer from the percpu variable
54 * offset.
55 */
56#define per_cpu(var, cpu) \
57 (*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
58#define __get_cpu_var(var) \
59 (*SHIFT_PERCPU_PTR(&(var), my_cpu_offset))
60#define __raw_get_cpu_var(var) \
61 (*SHIFT_PERCPU_PTR(&(var), __my_cpu_offset))
62
63#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
64#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
65
66
67#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
68extern void setup_per_cpu_areas(void);
69#endif
70
71#else /* ! SMP */
72
73#define per_cpu(var, cpu) (*((void)(cpu), &(var)))
74#define __get_cpu_var(var) (var)
75#define __raw_get_cpu_var(var) (var)
76#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
77#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
78
79#endif /* SMP */
80
81#ifndef PER_CPU_BASE_SECTION
82#ifdef CONFIG_SMP
83#define PER_CPU_BASE_SECTION ".data..percpu"
84#else
85#define PER_CPU_BASE_SECTION ".data"
86#endif
87#endif
88
89#ifdef CONFIG_SMP
90
91#ifdef MODULE
92#define PER_CPU_SHARED_ALIGNED_SECTION ""
93#define PER_CPU_ALIGNED_SECTION ""
94#else
95#define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"
96#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
97#endif
98#define PER_CPU_FIRST_SECTION "..first"
99
100#else
101
102#define PER_CPU_SHARED_ALIGNED_SECTION ""
103#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
104#define PER_CPU_FIRST_SECTION ""
105
106#endif
107
108#ifndef PER_CPU_ATTRIBUTES
109#define PER_CPU_ATTRIBUTES
110#endif
111
112#ifndef PER_CPU_DEF_ATTRIBUTES
113#define PER_CPU_DEF_ATTRIBUTES
114#endif
115
116#endif /* _ASM_GENERIC_PERCPU_H_ */