 06d5e032ad
			
		
	
	
	06d5e032ad
	
	
	
		
			
			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>
		
			
				
	
	
		
			99 lines
		
	
	
	
		
			2.4 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			99 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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| 
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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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| 
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| 
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| /* PAGE_SHIFT determines the page size */
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| 
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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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| 
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| #include <asm/setup.h>
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| 
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| #ifndef __ASSEMBLY__
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| 
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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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| 
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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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| 
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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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| /*
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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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| 
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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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| 
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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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| 
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| extern unsigned long memory_start;
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| extern unsigned long memory_end;
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| 
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| #endif /* !__ASSEMBLY__ */
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| 
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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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| 
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| #ifndef __ASSEMBLY__
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| #define pfn_valid(pfn)		((pfn) < max_mapnr)
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| 
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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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| 
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| #endif /* __ASSEMBLY__ */
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| 
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| #include <asm-generic/memory_model.h>
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| #include <asm-generic/getorder.h>
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| 
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| #endif /* __ASM_GENERIC_PAGE_H */
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