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