Linux kernel mirror (for testing)
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linux
1#ifndef __ALPHA_PERCPU_H
2#define __ALPHA_PERCPU_H
3
4#include <linux/compiler.h>
5#include <linux/threads.h>
6#include <linux/percpu-defs.h>
7
8/*
9 * Determine the real variable name from the name visible in the
10 * kernel sources.
11 */
12#define per_cpu_var(var) per_cpu__##var
13
14#ifdef CONFIG_SMP
15
16/*
17 * per_cpu_offset() is the offset that has to be added to a
18 * percpu variable to get to the instance for a certain processor.
19 */
20extern unsigned long __per_cpu_offset[NR_CPUS];
21
22#define per_cpu_offset(x) (__per_cpu_offset[x])
23
24#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
25#ifdef CONFIG_DEBUG_PREEMPT
26#define my_cpu_offset per_cpu_offset(smp_processor_id())
27#else
28#define my_cpu_offset __my_cpu_offset
29#endif
30
31#ifndef MODULE
32#define SHIFT_PERCPU_PTR(var, offset) RELOC_HIDE(&per_cpu_var(var), (offset))
33#define PER_CPU_DEF_ATTRIBUTES
34#else
35/*
36 * To calculate addresses of locally defined variables, GCC uses 32-bit
37 * displacement from the GP. Which doesn't work for per cpu variables in
38 * modules, as an offset to the kernel per cpu area is way above 4G.
39 *
40 * This forces allocation of a GOT entry for per cpu variable using
41 * ldq instruction with a 'literal' relocation.
42 */
43#define SHIFT_PERCPU_PTR(var, offset) ({ \
44 extern int simple_identifier_##var(void); \
45 unsigned long __ptr, tmp_gp; \
46 asm ( "br %1, 1f \n\
47 1: ldgp %1, 0(%1) \n\
48 ldq %0, per_cpu__" #var"(%1)\t!literal" \
49 : "=&r"(__ptr), "=&r"(tmp_gp)); \
50 (typeof(&per_cpu_var(var)))(__ptr + (offset)); })
51
52#define PER_CPU_DEF_ATTRIBUTES __used
53
54#endif /* MODULE */
55
56/*
57 * A percpu variable may point to a discarded regions. The following are
58 * established ways to produce a usable pointer from the percpu variable
59 * offset.
60 */
61#define per_cpu(var, cpu) \
62 (*SHIFT_PERCPU_PTR(var, per_cpu_offset(cpu)))
63#define __get_cpu_var(var) \
64 (*SHIFT_PERCPU_PTR(var, my_cpu_offset))
65#define __raw_get_cpu_var(var) \
66 (*SHIFT_PERCPU_PTR(var, __my_cpu_offset))
67
68#else /* ! SMP */
69
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)
73
74#define PER_CPU_DEF_ATTRIBUTES
75
76#endif /* SMP */
77
78#ifdef CONFIG_SMP
79#define PER_CPU_BASE_SECTION ".data.percpu"
80#else
81#define PER_CPU_BASE_SECTION ".data"
82#endif
83
84#ifdef CONFIG_SMP
85
86#ifdef MODULE
87#define PER_CPU_SHARED_ALIGNED_SECTION ""
88#else
89#define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned"
90#endif
91#define PER_CPU_FIRST_SECTION ".first"
92
93#else
94
95#define PER_CPU_SHARED_ALIGNED_SECTION ""
96#define PER_CPU_FIRST_SECTION ""
97
98#endif
99
100#define PER_CPU_ATTRIBUTES
101
102#endif /* __ALPHA_PERCPU_H */