LXR linux/include/asm-generic/memory

   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_VMEMMAP)
  50
  51/* memmap is virtually contigious.  */
  52#define __pfn_to_page(pfn)      (vmemmap + (pfn))
  53#define __page_to_pfn(page)     ((page) - vmemmap)
  54
  55#elif defined(CONFIG_SPARSEMEM)
  56/*
  57 * Note: section's mem_map is encorded to reflect its start_pfn.
  58 * section[i].section_mem_map == mem_map's address - start_pfn;
  59 */
  60#define __page_to_pfn(pg)                                       \
  61({      struct page *__pg = (pg);                               \
  62        int __sec = page_to_section(__pg);                      \
  63        (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
  64})
  65
  66#define __pfn_to_page(pfn)                              \
  67({      unsigned long __pfn = (pfn);                    \
  68        struct mem_section *__sec = __pfn_to_section(__pfn);    \
  69        __section_mem_map_addr(__sec) + __pfn;          \
  70})
  71#endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */
  72
  73#ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
  74struct page;
  75/* this is useful when inlined pfn_to_page is too big */
  76extern struct page *pfn_to_page(unsigned long pfn);
  77extern unsigned long page_to_pfn(struct page *page);
  78#else
  79#define page_to_pfn __page_to_pfn
  80#define pfn_to_page __pfn_to_page
  81#endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
  82
  83#endif /* __ASSEMBLY__ */
  84#endif /* __KERNEL__ */
  85
  86#endif
  87