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      1 #ifndef __ASM_MEMORY_MODEL_H
      2 #define __ASM_MEMORY_MODEL_H
      3 
      4 #ifdef __KERNEL__
      5 #ifndef __ASSEMBLY__
      6 
      7 #if defined(CONFIG_FLATMEM)
      8 
      9 #ifndef ARCH_PFN_OFFSET
     10 #define ARCH_PFN_OFFSET		(0UL)
     11 #endif
     12 
     13 #elif defined(CONFIG_DISCONTIGMEM)
     14 
     15 #ifndef arch_pfn_to_nid
     16 #define arch_pfn_to_nid(pfn)	pfn_to_nid(pfn)
     17 #endif
     18 
     19 #ifndef arch_local_page_offset
     20 #define arch_local_page_offset(pfn, nid)	\
     21 	((pfn) - NODE_DATA(nid)->node_start_pfn)
     22 #endif
     23 
     24 #endif /* CONFIG_DISCONTIGMEM */
     25 
     26 /*
     27  * supports 3 memory models.
     28  */
     29 #if defined(CONFIG_FLATMEM)
     30 
     31 #define __pfn_to_page(pfn)	(mem_map + ((pfn) - ARCH_PFN_OFFSET))
     32 #define __page_to_pfn(page)	((unsigned long)((page) - mem_map) + \
     33 				 ARCH_PFN_OFFSET)
     34 #elif defined(CONFIG_DISCONTIGMEM)
     35 
     36 #define __pfn_to_page(pfn)			\
     37 ({	unsigned long __pfn = (pfn);		\
     38 	unsigned long __nid = arch_pfn_to_nid(pfn);  \
     39 	NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\
     40 })
     41 
     42 #define __page_to_pfn(pg)						\
     43 ({	struct page *__pg = (pg);					\
     44 	struct pglist_data *__pgdat = NODE_DATA(page_to_nid(__pg));	\
     45 	(unsigned long)(__pg - __pgdat->node_mem_map) +			\
     46 	 __pgdat->node_start_pfn;					\
     47 })
     48 
     49 #elif defined(CONFIG_SPARSEMEM)
     50 /*
     51  * Note: section's mem_map is encorded to reflect its start_pfn.
     52  * section[i].section_mem_map == mem_map's address - start_pfn;
     53  */
     54 #define __page_to_pfn(pg)					\
     55 ({	struct page *__pg = (pg);				\
     56 	int __sec = page_to_section(__pg);			\
     57 	__pg - __section_mem_map_addr(__nr_to_section(__sec));	\
     58 })
     59 
     60 #define __pfn_to_page(pfn)				\
     61 ({	unsigned long __pfn = (pfn);			\
     62 	struct mem_section *__sec = __pfn_to_section(__pfn);	\
     63 	__section_mem_map_addr(__sec) + __pfn;		\
     64 })
     65 #endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */
     66 
     67 #ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
     68 struct page;
     69 /* this is useful when inlined pfn_to_page is too big */
     70 extern struct page *pfn_to_page(unsigned long pfn);
     71 extern unsigned long page_to_pfn(struct page *page);
     72 #else
     73 #define page_to_pfn __page_to_pfn
     74 #define pfn_to_page __pfn_to_page
     75 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
     76 
     77 #endif /* __ASSEMBLY__ */
     78 #endif /* __KERNEL__ */
     79 
     80 #endif
     81