page.h

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 */
#ifndef _ASM_PAGE_H
#define _ASM_PAGE_H

#include <linux/config.h>

/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT	12
#define PAGE_SIZE	(1UL << PAGE_SHIFT)
#define PAGE_MASK	(~(PAGE_SIZE-1))

#ifdef __KERNEL__

#ifndef _LANGUAGE_ASSEMBLY

#define BUG() do { printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__); *(int *)0=0; } while (0)
#define PAGE_BUG(page) do {  BUG(); } while (0)

extern void (*_clear_page)(void * page);
extern void (*_copy_page)(void * to, void * from);

#define clear_page(page)	_clear_page(page)
#define copy_page(to, from)	_copy_page(to, from)
#define clear_user_page(page, vaddr)	clear_page(page)
#define copy_user_page(to, from, vaddr)	copy_page(to, from)

/*
 * These are used to make use of C type-checking..
 */
typedef struct { unsigned long pte; } pte_t;
typedef struct { unsigned long pmd; } pmd_t;
typedef struct { unsigned long pgd; } pgd_t;
typedef struct { unsigned long pgprot; } pgprot_t;

#define pte_val(x)	((x).pte)
#define pmd_val(x)	((x).pmd)
#define pgd_val(x)	((x).pgd)
#define pgprot_val(x)	((x).pgprot)

#define __pte(x)	((pte_t) { (x) } )
#define __pme(x)	((pme_t) { (x) } )
#define __pgd(x)	((pgd_t) { (x) } )
#define __pgprot(x)	((pgprot_t) { (x) } )

#endif /* _LANGUAGE_ASSEMBLY */

/* to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr)	(((addr)+PAGE_SIZE-1)&PAGE_MASK)

/*
 * This handles the memory map.
 * We handle pages at KSEG0 for kernels with upto 512mb of memory,
 * at XKPHYS for kernels with more than that.
 */
#ifdef CONFIG_SGI_IP22
#define PAGE_OFFSET	0xffffffff80000000UL
#endif
#ifdef CONFIG_SGI_IP27
#define PAGE_OFFSET	0xa800000000000000UL
#endif

#define __pa(x)		((unsigned long) (x) - PAGE_OFFSET)
#define __va(x)		((void *)((unsigned long) (x) + PAGE_OFFSET))
#ifndef CONFIG_DISCONTIGMEM
#define virt_to_page(kaddr)	(mem_map + (__pa(kaddr) >> PAGE_SHIFT))
#define VALID_PAGE(page)	((page - mem_map) < max_mapnr)
#endif

#endif /* defined (__KERNEL__) */

#endif /* _ASM_PAGE_H */