Flexible Per-CPU Data

This group contains the implementation to support flexible per-CPU data. More...

Files
file	percpudata.h
	This header file provides the interfaces of the Flexible Per-CPU Data.
file	percpudata.c
	This source file contains the per-CPU data linker set and its system initialization handler.

Macros
#define	PER_CPU_DATA_NEED_INITIALIZATION()    RTEMS_LINKER_RWSET_DECLARE( _Per_CPU_Data, char )
	Translation units which define per-CPU items shall call this macro exactly once at file scope.
#define	PER_CPU_DATA_ITEM_DECLARE(type, item)    RTEMS_LINKER_RWSET_ITEM_DECLARE( _Per_CPU_Data, type, item )
	Declares a per-CPU item of the specified type.
#define	PER_CPU_DATA_ITEM(type, item)    RTEMS_LINKER_RWSET_ITEM( _Per_CPU_Data, type, item )
	Defines a per-CPU item of the specified type.
#define	PER_CPU_DATA_OFFSET(item)
	Returns the offset of the per-CPU item to the begin of the per-CPU data area.
#define	PER_CPU_DATA_GET_BY_OFFSET(cpu, type, offset)
	Returns a pointer of the specified type to the per-CPU item at the specified offset for the specified processor.
#define	PER_CPU_DATA_GET(cpu, type, item)    &_Linker_set__Per_CPU_Data_##item, (void) cpu
	Returns a pointer of the specified type to the specified per-CPU item for the specified processor.

Functions
	RTEMS_LINKER_RWSET_DECLARE (_Per_CPU_Data, char)

Detailed Description

This group contains the implementation to support flexible per-CPU data.

Macros to define custom per-CPU items are provided. The items are collected in a special linker set. During system initialization the content of the linker set is duplicated for all secondary processors using memory allocated from the workspace. The begin and end of the per-CPU data area is cache line aligned (CPU_CACHE_LINE_BYTES).

Macro Definition Documentation

PER_CPU_DATA_GET

#define PER_CPU_DATA_GET	(		cpu,
			type,
			item
	)		&_Linker_set__Per_CPU_Data_##item, (void) cpu

Returns a pointer of the specified type to the specified per-CPU item for the specified processor.

Parameters

cpu	The processor of the item.
type	The type of the item.
item	The designator of the item.

PER_CPU_DATA_GET_BY_OFFSET

#define PER_CPU_DATA_GET_BY_OFFSET	(		cpu,
			type,
			offset
	)

Value:

  (type *) ( (uintptr_t) RTEMS_LINKER_SET_BEGIN( _Per_CPU_Data ) + offset ), \
    (void) cpu

Returns a pointer of the specified type to the per-CPU item at the specified offset for the specified processor.

Parameters

cpu	The processor of the item.
type	The type of the item.
offset	The offset of the item.

PER_CPU_DATA_ITEM

#define PER_CPU_DATA_ITEM	(		type,
			item
	)		RTEMS_LINKER_RWSET_ITEM( _Per_CPU_Data, type, item )

Defines a per-CPU item of the specified type.

Parameters

type	The type of the item.
item	The designator of the item.

PER_CPU_DATA_ITEM_DECLARE

#define PER_CPU_DATA_ITEM_DECLARE	(		type,
			item
	)		RTEMS_LINKER_RWSET_ITEM_DECLARE( _Per_CPU_Data, type, item )

Declares a per-CPU item of the specified type.

Items declared with this macro have external linkage.

Parameters

type	The type of the item.
item	The designator of the item.

PER_CPU_DATA_OFFSET

#define PER_CPU_DATA_OFFSET

(

item

)

Value:

  ( (uintptr_t) &_Linker_set__Per_CPU_Data_##item \
    - (uintptr_t) RTEMS_LINKER_SET_BEGIN( _Per_CPU_Data ) )

Returns the offset of the per-CPU item to the begin of the per-CPU data area.

Parameters

item	The designator of the item.