memory_model.h

Go to the documentation of this file.

#ifndef __ASM_MEMORY_MODEL_H
#define __ASM_MEMORY_MODEL_H

#ifndef __ASSEMBLY__

#if defined(CONFIG_FLATMEM)

#ifndef ARCH_PFN_OFFSET
#define ARCH_PFN_OFFSET     (0UL)
#endif

#elif defined(CONFIG_DISCONTIGMEM)

#ifndef arch_pfn_to_nid
#define arch_pfn_to_nid(pfn)    pfn_to_nid(pfn)
#endif

#ifndef arch_local_page_offset
#define arch_local_page_offset(pfn, nid)    \
    ((pfn) - NODE_DATA(nid)->node_start_pfn)
#endif

#endif /* CONFIG_DISCONTIGMEM */

/*
 * supports 3 memory models.
 */
#if defined(CONFIG_FLATMEM)

#define __pfn_to_page(pfn)  (mem_map + ((pfn) - ARCH_PFN_OFFSET))
#define __page_to_pfn(page) ((unsigned long)((page) - mem_map) + \
                 ARCH_PFN_OFFSET)
#elif defined(CONFIG_DISCONTIGMEM)

#define __pfn_to_page(pfn)          \
({  unsigned long __pfn = (pfn);        \
    unsigned long __nid = arch_pfn_to_nid(__pfn);  \
    NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\
})

#define __page_to_pfn(pg)                       \
({  const struct page *__pg = (pg);                 \
    struct pglist_data *__pgdat = NODE_DATA(page_to_nid(__pg)); \
    (unsigned long)(__pg - __pgdat->node_mem_map) +         \
     __pgdat->node_start_pfn;                   \
})

#elif defined(CONFIG_SPARSEMEM_VMEMMAP)

/* memmap is virtually contiguous.  */
#define __pfn_to_page(pfn)  (vmemmap + (pfn))
#define __page_to_pfn(page) (unsigned long)((page) - vmemmap)

#elif defined(CONFIG_SPARSEMEM)
/*
 * Note: section's mem_map is encorded to reflect its start_pfn.
 * section[i].section_mem_map == mem_map's address - start_pfn;
 */
#define __page_to_pfn(pg)                   \
({  const struct page *__pg = (pg);             \
    int __sec = page_to_section(__pg);          \
    (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
})

#define __pfn_to_page(pfn)              \
({  unsigned long __pfn = (pfn);            \
    struct mem_section *__sec = __pfn_to_section(__pfn);    \
    __section_mem_map_addr(__sec) + __pfn;      \
})
#endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */

#define page_to_pfn __page_to_pfn
#define pfn_to_page __pfn_to_page

#endif /* __ASSEMBLY__ */

#endif