Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _ASM_GENERIC_PERCPU_H_ |
| 2 | #define _ASM_GENERIC_PERCPU_H_ |
| 3 | #include <linux/compiler.h> |
Rusty Russell | ae1ee11 | 2007-05-02 19:27:10 +0200 | [diff] [blame] | 4 | #include <linux/threads.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5 | |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #ifdef CONFIG_SMP |
| 13 | |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 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 | * 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). |
| 20 | */ |
| 21 | #ifndef __per_cpu_offset |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 22 | extern unsigned long __per_cpu_offset[NR_CPUS]; |
| 23 | |
Ingo Molnar | a875a69 | 2006-07-03 00:24:26 -0700 | [diff] [blame] | 24 | #define per_cpu_offset(x) (__per_cpu_offset[x]) |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 25 | #endif |
Ingo Molnar | a875a69 | 2006-07-03 00:24:26 -0700 | [diff] [blame] | 26 | |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 27 | /* |
| 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. |
| 32 | */ |
| 33 | #ifndef __my_cpu_offset |
| 34 | #define __my_cpu_offset per_cpu_offset(raw_smp_processor_id()) |
Hugh Dickins | 1e83527 | 2008-02-23 19:40:17 +0000 | [diff] [blame] | 35 | #endif |
| 36 | #ifdef CONFIG_DEBUG_PREEMPT |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 37 | #define my_cpu_offset per_cpu_offset(smp_processor_id()) |
| 38 | #else |
| 39 | #define my_cpu_offset __my_cpu_offset |
| 40 | #endif |
| 41 | |
| 42 | /* |
| 43 | * Add a offset to a pointer but keep the pointer as is. |
| 44 | * |
| 45 | * Only S390 provides its own means of moving the pointer. |
| 46 | */ |
| 47 | #ifndef SHIFT_PERCPU_PTR |
| 48 | #define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset)) |
| 49 | #endif |
| 50 | |
| 51 | /* |
Mike Travis | dd5af90 | 2008-01-30 13:33:32 +0100 | [diff] [blame] | 52 | * A percpu variable may point to a discarded regions. The following are |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 53 | * established ways to produce a usable pointer from the percpu variable |
| 54 | * offset. |
| 55 | */ |
| 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)) |
| 62 | |
| 63 | |
Mike Travis | dd5af90 | 2008-01-30 13:33:32 +0100 | [diff] [blame] | 64 | #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 65 | extern void setup_per_cpu_areas(void); |
| 66 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | #else /* ! SMP */ |
| 69 | |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 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) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | |
| 74 | #endif /* SMP */ |
| 75 | |
travis@sgi.com | acdac87 | 2008-01-30 13:32:52 +0100 | [diff] [blame] | 76 | #ifndef PER_CPU_ATTRIBUTES |
| 77 | #define PER_CPU_ATTRIBUTES |
| 78 | #endif |
| 79 | |
| 80 | #define DECLARE_PER_CPU(type, name) extern PER_CPU_ATTRIBUTES \ |
| 81 | __typeof__(type) per_cpu_var(name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
Ingo Molnar | 6dbde35 | 2009-01-15 22:15:53 +0900 | [diff] [blame] | 83 | /* |
| 84 | * Optional methods for optimized non-lvalue per-cpu variable access. |
| 85 | * |
| 86 | * @var can be a percpu variable or a field of it and its size should |
| 87 | * equal char, int or long. percpu_read() evaluates to a lvalue and |
| 88 | * all others to void. |
| 89 | * |
| 90 | * These operations are guaranteed to be atomic w.r.t. preemption. |
| 91 | * The generic versions use plain get/put_cpu_var(). Archs are |
| 92 | * encouraged to implement single-instruction alternatives which don't |
| 93 | * require preemption protection. |
| 94 | */ |
| 95 | #ifndef percpu_read |
| 96 | # define percpu_read(var) \ |
| 97 | ({ \ |
| 98 | typeof(per_cpu_var(var)) __tmp_var__; \ |
| 99 | __tmp_var__ = get_cpu_var(var); \ |
| 100 | put_cpu_var(var); \ |
| 101 | __tmp_var__; \ |
| 102 | }) |
| 103 | #endif |
| 104 | |
| 105 | #define __percpu_generic_to_op(var, val, op) \ |
| 106 | do { \ |
| 107 | get_cpu_var(var) op val; \ |
| 108 | put_cpu_var(var); \ |
| 109 | } while (0) |
| 110 | |
| 111 | #ifndef percpu_write |
| 112 | # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =) |
| 113 | #endif |
| 114 | |
| 115 | #ifndef percpu_add |
| 116 | # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=) |
| 117 | #endif |
| 118 | |
| 119 | #ifndef percpu_sub |
| 120 | # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=) |
| 121 | #endif |
| 122 | |
| 123 | #ifndef percpu_and |
| 124 | # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=) |
| 125 | #endif |
| 126 | |
| 127 | #ifndef percpu_or |
| 128 | # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=) |
| 129 | #endif |
| 130 | |
| 131 | #ifndef percpu_xor |
| 132 | # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=) |
| 133 | #endif |
| 134 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | #endif /* _ASM_GENERIC_PERCPU_H_ */ |