1 files changed, 77 insertions, 0 deletions

diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
new file mode 100644
index 000000000000..0cfb086dd373
--- /dev/null
+++ b/include/asm-generic/memory_model.h
@@ -0,0 +1,77 @@
+#ifndef __ASM_MEMORY_MODEL_H
+#define __ASM_MEMORY_MODEL_H
+
+#ifdef __KERNEL__
+#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 */
+
+#ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
+struct page;
+/* this is useful when inlined pfn_to_page is too big */
+extern struct page *pfn_to_page(unsigned long pfn);
+extern unsigned long page_to_pfn(struct page *page);
+#else
+/*
+ * 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)                                                 \
+({      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)
+/*
+ * 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)                                 \
+({      struct page *__pg = (pg);                               \
+        int __sec = page_to_section(__pg);                      \
+        __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 */
+#endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
+
+#endif /* __ASSEMBLY__ */
+#endif /* __KERNEL__ */
+
+#endif