1 files changed, 86 insertions, 0 deletions
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
new file mode 100644
index 000000000..7637fb46b
--- /dev/null
+++ b/include/asm-generic/memory_model.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_MEMORY_MODEL_H
+#define __ASM_MEMORY_MODEL_H
+
+#include <linux/pfn.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 encoded 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 */
+
+/*
+ * Convert a physical address to a Page Frame Number and back
+ */
+#define	__phys_to_pfn(paddr)	PHYS_PFN(paddr)
+#define	__pfn_to_phys(pfn)	PFN_PHYS(pfn)
+
+#define page_to_pfn __page_to_pfn
+#define pfn_to_page __pfn_to_page
+
+#endif /* __ASSEMBLY__ */
+
+#endif