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