Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef __ALPHA_PERCPU_H |
| 2 | #define __ALPHA_PERCPU_H |
Tejun Heo | 9aa7a7d | 2009-05-12 13:19:39 -0700 | [diff] [blame] | 3 | |
Ivan Kokshaysky | 9267b4b | 2008-06-21 03:25:39 +0400 | [diff] [blame] | 4 | #include <linux/compiler.h> |
| 5 | #include <linux/threads.h> |
Tejun Heo | 9aa7a7d | 2009-05-12 13:19:39 -0700 | [diff] [blame] | 6 | #include <linux/percpu-defs.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | |
Ivan Kokshaysky | 9267b4b | 2008-06-21 03:25:39 +0400 | [diff] [blame] | 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 | */ |
| 20 | extern 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)) |
Ivan Kokshaysky | 9267b4b | 2008-06-21 03:25:39 +0400 | [diff] [blame] | 33 | #else |
| 34 | /* |
| 35 | * To calculate addresses of locally defined variables, GCC uses 32-bit |
| 36 | * displacement from the GP. Which doesn't work for per cpu variables in |
| 37 | * modules, as an offset to the kernel per cpu area is way above 4G. |
| 38 | * |
| 39 | * This forces allocation of a GOT entry for per cpu variable using |
| 40 | * ldq instruction with a 'literal' relocation. |
| 41 | */ |
| 42 | #define SHIFT_PERCPU_PTR(var, offset) ({ \ |
| 43 | extern int simple_identifier_##var(void); \ |
| 44 | unsigned long __ptr, tmp_gp; \ |
| 45 | asm ( "br %1, 1f \n\ |
| 46 | 1: ldgp %1, 0(%1) \n\ |
| 47 | ldq %0, per_cpu__" #var"(%1)\t!literal" \ |
| 48 | : "=&r"(__ptr), "=&r"(tmp_gp)); \ |
| 49 | (typeof(&per_cpu_var(var)))(__ptr + (offset)); }) |
| 50 | |
Ivan Kokshaysky | 9267b4b | 2008-06-21 03:25:39 +0400 | [diff] [blame] | 51 | #endif /* MODULE */ |
| 52 | |
| 53 | /* |
| 54 | * A percpu variable may point to a discarded regions. The following are |
| 55 | * established ways to produce a usable pointer from the percpu variable |
| 56 | * offset. |
| 57 | */ |
| 58 | #define per_cpu(var, cpu) \ |
| 59 | (*SHIFT_PERCPU_PTR(var, per_cpu_offset(cpu))) |
| 60 | #define __get_cpu_var(var) \ |
| 61 | (*SHIFT_PERCPU_PTR(var, my_cpu_offset)) |
| 62 | #define __raw_get_cpu_var(var) \ |
| 63 | (*SHIFT_PERCPU_PTR(var, __my_cpu_offset)) |
| 64 | |
| 65 | #else /* ! SMP */ |
| 66 | |
| 67 | #define per_cpu(var, cpu) (*((void)(cpu), &per_cpu_var(var))) |
| 68 | #define __get_cpu_var(var) per_cpu_var(var) |
| 69 | #define __raw_get_cpu_var(var) per_cpu_var(var) |
| 70 | |
| 71 | #endif /* SMP */ |
| 72 | |
Tejun Heo | 9aa7a7d | 2009-05-12 13:19:39 -0700 | [diff] [blame] | 73 | #ifdef CONFIG_SMP |
| 74 | #define PER_CPU_BASE_SECTION ".data.percpu" |
| 75 | #else |
| 76 | #define PER_CPU_BASE_SECTION ".data" |
| 77 | #endif |
| 78 | |
| 79 | #ifdef CONFIG_SMP |
| 80 | |
| 81 | #ifdef MODULE |
| 82 | #define PER_CPU_SHARED_ALIGNED_SECTION "" |
| 83 | #else |
| 84 | #define PER_CPU_SHARED_ALIGNED_SECTION ".shared_aligned" |
| 85 | #endif |
| 86 | #define PER_CPU_FIRST_SECTION ".first" |
| 87 | |
| 88 | #else |
| 89 | |
| 90 | #define PER_CPU_SHARED_ALIGNED_SECTION "" |
| 91 | #define PER_CPU_FIRST_SECTION "" |
| 92 | |
| 93 | #endif |
| 94 | |
| 95 | #define PER_CPU_ATTRIBUTES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | |
| 97 | #endif /* __ALPHA_PERCPU_H */ |