page.h

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#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 ARCH_PFN_OFFSET
#define ARCH_PFN_OFFSET     (PAGE_OFFSET >> PAGE_SHIFT)
#endif

#ifndef __ASSEMBLY__

#define __va(x) ((void *)((unsigned long) (x)))
#define __pa(x) ((unsigned long) (x))

#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) >= ARCH_PFN_OFFSET && ((pfn) - ARCH_PFN_OFFSET) < 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 */