Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux...
[wrt350n-kernel.git] / include / asm-generic / percpu.h
blobb0e63c672ebdf5a065ddea3374558a9638bc43c1
1 #ifndef _ASM_GENERIC_PERCPU_H_
2 #define _ASM_GENERIC_PERCPU_H_
3 #include <linux/compiler.h>
4 #include <linux/threads.h>
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
12 #ifdef CONFIG_SMP
15 * per_cpu_offset() is the offset that has to be added to a
16 * percpu variable to get to the instance for a certain processor.
18 * Most arches use the __per_cpu_offset array for those offsets but
19 * some arches have their own ways of determining the offset (x86_64, s390).
21 #ifndef __per_cpu_offset
22 extern unsigned long __per_cpu_offset[NR_CPUS];
24 #define per_cpu_offset(x) (__per_cpu_offset[x])
25 #endif
28 * Determine the offset for the currently active processor.
29 * An arch may define __my_cpu_offset to provide a more effective
30 * means of obtaining the offset to the per cpu variables of the
31 * current processor.
33 #ifndef __my_cpu_offset
34 #define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
35 #endif
36 #ifdef CONFIG_DEBUG_PREEMPT
37 #define my_cpu_offset per_cpu_offset(smp_processor_id())
38 #else
39 #define my_cpu_offset __my_cpu_offset
40 #endif
43 * Add a offset to a pointer but keep the pointer as is.
45 * Only S390 provides its own means of moving the pointer.
47 #ifndef SHIFT_PERCPU_PTR
48 #define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset))
49 #endif
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.
56 #define per_cpu(var, cpu) \
57 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), per_cpu_offset(cpu)))
58 #define __get_cpu_var(var) \
59 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), my_cpu_offset))
60 #define __raw_get_cpu_var(var) \
61 (*SHIFT_PERCPU_PTR(&per_cpu_var(var), __my_cpu_offset))
64 #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
65 extern void setup_per_cpu_areas(void);
66 #endif
68 #else /* ! SMP */
70 #define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var)))
71 #define __get_cpu_var(var) per_cpu_var(var)
72 #define __raw_get_cpu_var(var) per_cpu_var(var)
74 #endif /* SMP */
76 #ifndef PER_CPU_ATTRIBUTES
77 #define PER_CPU_ATTRIBUTES
78 #endif
80 #define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \
81 __typeof__(type) per_cpu_var(name)
83 #endif /* _ASM_GENERIC_PERCPU_H_ */