1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __ASM_MEMORY_MODEL_H
3#define __ASM_MEMORY_MODEL_H
4
5#include <linux/pfn.h>
6
7#ifndef __ASSEMBLY__
8
9/*
10 * supports 3 memory models.
11 */
12#if defined(CONFIG_FLATMEM)
13
14#ifndef ARCH_PFN_OFFSET
15#define ARCH_PFN_OFFSET (0UL)
16#endif
17
18#define __pfn_to_page(pfn) (mem_map + ((pfn) - ARCH_PFN_OFFSET))
19#define __page_to_pfn(page) ((unsigned long)((page) - mem_map) + \
20 ARCH_PFN_OFFSET)
21
22#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
23
24/* memmap is virtually contiguous. */
25#define __pfn_to_page(pfn) (vmemmap + (pfn))
26#define __page_to_pfn(page) (unsigned long)((page) - vmemmap)
27
28#elif defined(CONFIG_SPARSEMEM)
29/*
30 * Note: section's mem_map is encoded to reflect its start_pfn.
31 * section[i].section_mem_map == mem_map's address - start_pfn;
32 */
33#define __page_to_pfn(pg) \
34({ const struct page *__pg = (pg); \
35 int __sec = page_to_section(__pg); \
36 (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
37})
38
39#define __pfn_to_page(pfn) \
40({ unsigned long __pfn = (pfn); \
41 struct mem_section *__sec = __pfn_to_section(__pfn); \
42 __section_mem_map_addr(__sec) + __pfn; \
43})
44#endif /* CONFIG_FLATMEM/SPARSEMEM */
45
46/*
47 * Convert a physical address to a Page Frame Number and back
48 */
49#define __phys_to_pfn(paddr) PHYS_PFN(paddr)
50#define __pfn_to_phys(pfn) PFN_PHYS(pfn)
51
52#define page_to_pfn __page_to_pfn
53#define pfn_to_page __pfn_to_page
54
55#endif /* __ASSEMBLY__ */
56
57#endif
58

source code of linux/include/asm-generic/memory_model.h