linux/include/asm-generic/page.h
Sonic Zhang 06d5e032ad include/asm-generic/page.h: calculate virt_to_page and page_to_virt via predefined macro
On NOMMU architectures, if physical memory doesn't start from 0,
ARCH_PFN_OFFSET is defined to generate page index in mem_map array.
Because virtual address is equal to physical address, PAGE_OFFSET is
always 0.  virt_to_page and page_to_virt should not index page by
PAGE_OFFSET directly.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31 17:30:48 -07:00

100 lines
2.4 KiB
C

#ifndef __ASM_GENERIC_PAGE_H
#define __ASM_GENERIC_PAGE_H
/*
* Generic page.h implementation, for NOMMU architectures.
* This provides the dummy definitions for the memory management.
*/
#ifdef CONFIG_MMU
#error need to prove a real asm/page.h
#endif
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
#ifdef __ASSEMBLY__
#define PAGE_SIZE (1 << PAGE_SHIFT)
#else
#define PAGE_SIZE (1UL << PAGE_SHIFT)
#endif
#define PAGE_MASK (~(PAGE_SIZE-1))
#include <asm/setup.h>
#ifndef __ASSEMBLY__
#define get_user_page(vaddr) __get_free_page(GFP_KERNEL)
#define free_user_page(page, addr) free_page(addr)
#define clear_page(page) memset((page), 0, PAGE_SIZE)
#define copy_page(to,from) memcpy((to), (from), PAGE_SIZE)
#define clear_user_page(page, vaddr, pg) clear_page(page)
#define copy_user_page(to, from, vaddr, pg) 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[16];
} pmd_t;
typedef struct {
unsigned long pgd;
} pgd_t;
typedef struct {
unsigned long pgprot;
} pgprot_t;
typedef struct page *pgtable_t;
#define pte_val(x) ((x).pte)
#define pmd_val(x) ((&x)->pmd[0])
#define pgd_val(x) ((x).pgd)
#define pgprot_val(x) ((x).pgprot)
#define __pte(x) ((pte_t) { (x) } )
#define __pmd(x) ((pmd_t) { (x) } )
#define __pgd(x) ((pgd_t) { (x) } )
#define __pgprot(x) ((pgprot_t) { (x) } )
extern unsigned long memory_start;
extern unsigned long memory_end;
#endif /* !__ASSEMBLY__ */
#ifdef CONFIG_KERNEL_RAM_BASE_ADDRESS
#define PAGE_OFFSET (CONFIG_KERNEL_RAM_BASE_ADDRESS)
#else
#define PAGE_OFFSET (0)
#endif
#ifndef __ASSEMBLY__
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
#define __pa(x) ((unsigned long) (x) - PAGE_OFFSET)
#define virt_to_pfn(kaddr) (__pa(kaddr) >> PAGE_SHIFT)
#define pfn_to_virt(pfn) __va((pfn) << PAGE_SHIFT)
#define virt_to_page(addr) pfn_to_page(virt_to_pfn(addr))
#define page_to_virt(page) pfn_to_virt(page_to_pfn(page))
#ifndef page_to_phys
#define page_to_phys(page) ((dma_addr_t)page_to_pfn(page) << PAGE_SHIFT)
#endif
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#define virt_addr_valid(kaddr) (((void *)(kaddr) >= (void *)PAGE_OFFSET) && \
((void *)(kaddr) < (void *)memory_end))
#endif /* __ASSEMBLY__ */
#include <asm-generic/memory_model.h>
#include <asm-generic/getorder.h>
#endif /* __ASM_GENERIC_PAGE_H */