percpu.h
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#ifndef _ASM_GENERIC_PERCPU_H_
#define _ASM_GENERIC_PERCPU_H_
#include <linux/compiler.h>
#include <linux/threads.h>
#include <linux/percpu-defs.h>
#ifdef CONFIG_SMP
/*
* per_cpu_offset() is the offset that has to be added to a
* percpu variable to get to the instance for a certain processor.
*
* Most arches use the __per_cpu_offset array for those offsets but
* some arches have their own ways of determining the offset (x86_64, s390).
*/
#ifndef __per_cpu_offset
extern unsigned long __per_cpu_offset[NR_CPUS];
#define per_cpu_offset(x) (__per_cpu_offset[x])
#endif
/*
* Determine the offset for the currently active processor.
* An arch may define __my_cpu_offset to provide a more effective
* means of obtaining the offset to the per cpu variables of the
* current processor.
*/
#ifndef __my_cpu_offset
#define __my_cpu_offset per_cpu_offset(raw_smp_processor_id())
#endif
#ifdef CONFIG_DEBUG_PREEMPT
#define my_cpu_offset per_cpu_offset(smp_processor_id())
#else
#define my_cpu_offset __my_cpu_offset
#endif
/*
* Add a offset to a pointer but keep the pointer as is.
*
* Only S390 provides its own means of moving the pointer.
*/
#ifndef SHIFT_PERCPU_PTR
/* Weird cast keeps both GCC and sparse happy. */
#define SHIFT_PERCPU_PTR(__p, __offset) ({ \
__verify_pcpu_ptr((__p)); \
RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
})
#endif
/*
* A percpu variable may point to a discarded regions. The following are
* established ways to produce a usable pointer from the percpu variable
* offset.
*/
#define per_cpu(var, cpu) \
(*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
#ifndef __this_cpu_ptr
#define __this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, __my_cpu_offset)
#endif
#ifdef CONFIG_DEBUG_PREEMPT
#define this_cpu_ptr(ptr) SHIFT_PERCPU_PTR(ptr, my_cpu_offset)
#else
#define this_cpu_ptr(ptr) __this_cpu_ptr(ptr)
#endif
#define __get_cpu_var(var) (*this_cpu_ptr(&(var)))
#define __raw_get_cpu_var(var) (*__this_cpu_ptr(&(var)))
#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
extern void setup_per_cpu_areas(void);
#endif
#else /* ! SMP */
#define VERIFY_PERCPU_PTR(__p) ({ \
__verify_pcpu_ptr((__p)); \
(typeof(*(__p)) __kernel __force *)(__p); \
})
#define per_cpu(var, cpu) (*((void)(cpu), VERIFY_PERCPU_PTR(&(var))))
#define __get_cpu_var(var) (*VERIFY_PERCPU_PTR(&(var)))
#define __raw_get_cpu_var(var) (*VERIFY_PERCPU_PTR(&(var)))
#define this_cpu_ptr(ptr) per_cpu_ptr(ptr, 0)
#define __this_cpu_ptr(ptr) this_cpu_ptr(ptr)
#endif /* SMP */
#ifndef PER_CPU_BASE_SECTION
#ifdef CONFIG_SMP
#define PER_CPU_BASE_SECTION ".data..percpu"
#else
#define PER_CPU_BASE_SECTION ".data"
#endif
#endif
#ifdef CONFIG_SMP
#ifdef MODULE
#define PER_CPU_SHARED_ALIGNED_SECTION ""
#define PER_CPU_ALIGNED_SECTION ""
#else
#define PER_CPU_SHARED_ALIGNED_SECTION "..shared_aligned"
#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
#endif
#define PER_CPU_FIRST_SECTION "..first"
#else
#define PER_CPU_SHARED_ALIGNED_SECTION ""
#define PER_CPU_ALIGNED_SECTION "..shared_aligned"
#define PER_CPU_FIRST_SECTION ""
#endif
#ifndef PER_CPU_ATTRIBUTES
#define PER_CPU_ATTRIBUTES
#endif
#ifndef PER_CPU_DEF_ATTRIBUTES
#define PER_CPU_DEF_ATTRIBUTES
#endif
#endif /* _ASM_GENERIC_PERCPU_H_ */