Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1#ifndef __ALPHA_PERCPU_H
2#define __ALPHA_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#ifdef CONFIG_SMP
13
14/*
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.
17 */
18extern unsigned long __per_cpu_offset[NR_CPUS];
19
20#define per_cpu_offset(x) (__per_cpu_offset[x])
21
22#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
23#ifdef CONFIG_DEBUG_PREEMPT
24#define my_cpu_offset per_cpu_offset(smp_processor_id())
25#else
26#define my_cpu_offset __my_cpu_offset
27#endif
28
29#ifndef MODULE
30#define SHIFT_PERCPU_PTR(var, offset) RELOC_HIDE(&per_cpu_var(var), (offset))
31#define PER_CPU_ATTRIBUTES
32#else
33/*
34 * To calculate addresses of locally defined variables, GCC uses 32-bit
35 * displacement from the GP. Which doesn't work for per cpu variables in
36 * modules, as an offset to the kernel per cpu area is way above 4G.
37 *
38 * This forces allocation of a GOT entry for per cpu variable using
39 * ldq instruction with a 'literal' relocation.
40 */
41#define SHIFT_PERCPU_PTR(var, offset) ({ \
42 extern int simple_identifier_##var(void); \
43 unsigned long __ptr, tmp_gp; \
44 asm ( "br %1, 1f \n\
45 1: ldgp %1, 0(%1) \n\
46 ldq %0, per_cpu__" #var"(%1)\t!literal" \
47 : "=&r"(__ptr), "=&r"(tmp_gp)); \
48 (typeof(&per_cpu_var(var)))(__ptr + (offset)); })
49
50#define PER_CPU_ATTRIBUTES __used
51
52#endif /* MODULE */
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(var, per_cpu_offset(cpu)))
61#define __get_cpu_var(var) \
62 (*SHIFT_PERCPU_PTR(var, my_cpu_offset))
63#define __raw_get_cpu_var(var) \
64 (*SHIFT_PERCPU_PTR(var, __my_cpu_offset))
65
66#else /* ! SMP */
67
68#define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var)))
69#define __get_cpu_var(var) per_cpu_var(var)
70#define __raw_get_cpu_var(var) per_cpu_var(var)
71
72#define PER_CPU_ATTRIBUTES
73
74#endif /* SMP */
75
76#define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name)
77
78#endif /* __ALPHA_PERCPU_H */