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[linux-2.6] / 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