include/asm-generic/memory_model.h

   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 #ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
  27 struct page;
  28 /* this is useful when inlined pfn_to_page is too big */
  29 extern struct page *pfn_to_page(unsigned long pfn);
  30 extern unsigned long page_to_pfn(struct page *page);
  31 #else
  32 /*
  33  * supports 3 memory models.
  34  */
  35 #if defined(CONFIG_FLATMEM)
  36
  37 #define pfn_to_page(pfn)        (mem_map + ((pfn) - ARCH_PFN_OFFSET))
  38 #define page_to_pfn(page)       ((unsigned long)((page) - mem_map) + \
  39                                  ARCH_PFN_OFFSET)
  40 #elif defined(CONFIG_DISCONTIGMEM)
  41
  42 #define pfn_to_page(pfn)                        \
  43 ({      unsigned long __pfn = (pfn);            \
  44         unsigned long __nid = arch_pfn_to_nid(pfn);  \
  45         NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\
  46 })
  47
  48 #define page_to_pfn(pg)                                                 \
  49 ({      struct page *__pg = (pg);                                       \
  50         struct pglist_data *__pgdat = NODE_DATA(page_to_nid(__pg));     \
  51         (unsigned long)(__pg - __pgdat->node_mem_map) +                 \
  52          __pgdat->node_start_pfn;                                       \
  53 })
  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         __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 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
  73
  74 #endif /* __ASSEMBLY__ */
  75 #endif /* __KERNEL__ */
  76
  77 #endif