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1 | #ifndef __ALPHA_PERCPU_H |
2 | #define __ALPHA_PERCPU_H | |
9267b4b3 IK |
3 | #include <linux/compiler.h> |
4 | #include <linux/threads.h> | |
1da177e4 | 5 | |
9267b4b3 IK |
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 | */ | |
18 | extern 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 | #endif /* SMP */ | |
73 | ||
74 | #define DECLARE_PER_CPU(type, name) extern __typeof__(type) per_cpu_var(name) | |
1da177e4 LT |
75 | |
76 | #endif /* __ALPHA_PERCPU_H */ |