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-rw-r--r--include/asm-generic/memory_model.h86
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