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