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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _ASM_GENERIC_PERCPU_H_
2#define _ASM_GENERIC_PERCPU_H_
David Howells5028eaa2009-04-21 23:00:29 +01003
Linus Torvalds1da177e2005-04-16 15:20:36 -07004#include <linux/compiler.h>
Rusty Russellae1ee112007-05-02 19:27:10 +02005#include <linux/threads.h>
David Howells5028eaa2009-04-21 23:00:29 +01006#include <linux/percpu-defs.h>
travis@sgi.comacdac872008-01-30 13:32:52 +01007
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#ifdef CONFIG_SMP
9
travis@sgi.comacdac872008-01-30 13:32:52 +010010/*
11 * per_cpu_offset() is the offset that has to be added to a
12 * percpu variable to get to the instance for a certain processor.
13 *
14 * Most arches use the __per_cpu_offset array for those offsets but
15 * some arches have their own ways of determining the offset (x86_64, s390).
16 */
17#ifndef __per_cpu_offset
Linus Torvalds1da177e2005-04-16 15:20:36 -070018extern unsigned long __per_cpu_offset[NR_CPUS];
19
Ingo Molnara875a692006-07-03 00:24:26 -070020#define per_cpu_offset(x) (__per_cpu_offset[x])
travis@sgi.comacdac872008-01-30 13:32:52 +010021#endif
Ingo Molnara875a692006-07-03 00:24:26 -070022
travis@sgi.comacdac872008-01-30 13:32:52 +010023/*
24 * Determine the offset for the currently active processor.
25 * An arch may define __my_cpu_offset to provide a more effective
26 * means of obtaining the offset to the per cpu variables of the
27 * current processor.
28 */
29#ifndef __my_cpu_offset
30#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
Hugh Dickins1e835272008-02-23 19:40:17 +000031#endif
32#ifdef CONFIG_DEBUG_PREEMPT
travis@sgi.comacdac872008-01-30 13:32:52 +010033#define my_cpu_offset per_cpu_offset(smp_processor_id())
34#else
35#define my_cpu_offset __my_cpu_offset
36#endif
37
38/*
39 * Add a offset to a pointer but keep the pointer as is.
40 *
41 * Only S390 provides its own means of moving the pointer.
42 */
43#ifndef SHIFT_PERCPU_PTR
Rusty Russelle0fdb0e2009-10-29 22:34:15 +090044/* Weird cast keeps both GCC and sparse happy. */
Tejun Heo545695f2009-10-29 22:34:15 +090045#define SHIFT_PERCPU_PTR(__p, __offset) ({ \
46 __verify_pcpu_ptr((__p)); \
47 RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
48})
travis@sgi.comacdac872008-01-30 13:32:52 +010049#endif
50
51/*
Mike Travisdd5af902008-01-30 13:33:32 +010052 * A percpu variable may point to a discarded regions. The following are
travis@sgi.comacdac872008-01-30 13:32:52 +010053 * established ways to produce a usable pointer from the percpu variable
54 * offset.
55 */
56#define per_cpu(var, cpu) \
Rusty Russelldd17c8f2009-10-29 22:34:15 +090057 (*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
travis@sgi.comacdac872008-01-30 13:32:52 +010058#define __get_cpu_var(var) \
Rusty Russelldd17c8f2009-10-29 22:34:15 +090059 (*SHIFT_PERCPU_PTR(&(var), my_cpu_offset))
travis@sgi.comacdac872008-01-30 13:32:52 +010060#define __raw_get_cpu_var(var) \
Rusty Russelldd17c8f2009-10-29 22:34:15 +090061 (*SHIFT_PERCPU_PTR(&(var), __my_cpu_offset))
travis@sgi.comacdac872008-01-30 13:32:52 +010062
Christoph Lameter7340a0b2009-10-03 19:48:22 +090063#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
64#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
65
travis@sgi.comacdac872008-01-30 13:32:52 +010066
Mike Travisdd5af902008-01-30 13:33:32 +010067#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
travis@sgi.comacdac872008-01-30 13:32:52 +010068extern void setup_per_cpu_areas(void);
69#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070070
Linus Torvalds1da177e2005-04-16 15:20:36 -070071#else /* ! SMP */
72
Rusty Russelldd17c8f2009-10-29 22:34:15 +090073#define per_cpu(var, cpu) (*((void)(cpu), &(var)))
74#define __get_cpu_var(var) (var)
75#define __raw_get_cpu_var(var) (var)
Christoph Lameter7340a0b2009-10-03 19:48:22 +090076#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
77#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79#endif /* SMP */
80
David Howells9b8de742009-04-21 23:00:24 +010081#ifndef PER_CPU_BASE_SECTION
82#ifdef CONFIG_SMP
Denys Vlasenko3d9a8542010-02-20 01:03:43 +010083#define PER_CPU_BASE_SECTION ".data..percpu"
David Howells9b8de742009-04-21 23:00:24 +010084#else
85#define PER_CPU_BASE_SECTION ".data"
86#endif
87#endif
88
89#ifdef CONFIG_SMP
90
91#ifdef MODULE
92#define PER_CPU_SHARED_ALIGNED_SECTION ""
Jeremy Fitzhardinge53f82452009-09-03 14:31:44 -070093#define PER_CPU_ALIGNED_SECTION ""
David Howells9b8de742009-04-21 23:00:24 +010094#else
Denys Vlasenko3d9a8542010-02-20 01:03:43 +010095#define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"
96#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
David Howells9b8de742009-04-21 23:00:24 +010097#endif
Denys Vlasenko3d9a8542010-02-20 01:03:43 +010098#define PER_CPU_FIRST_SECTION "..first"
David Howells9b8de742009-04-21 23:00:24 +010099
100#else
101
102#define PER_CPU_SHARED_ALIGNED_SECTION ""
Denys Vlasenko3d9a8542010-02-20 01:03:43 +0100103#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
David Howells9b8de742009-04-21 23:00:24 +0100104#define PER_CPU_FIRST_SECTION ""
105
106#endif
107
travis@sgi.comacdac872008-01-30 13:32:52 +0100108#ifndef PER_CPU_ATTRIBUTES
109#define PER_CPU_ATTRIBUTES
110#endif
111
Tejun Heob01e8dc2009-06-30 11:41:18 -0700112#ifndef PER_CPU_DEF_ATTRIBUTES
113#define PER_CPU_DEF_ATTRIBUTES
114#endif
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116#endif /* _ASM_GENERIC_PERCPU_H_ */