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#ifndef pfn_valid
23static inline int pfn_valid(unsigned long pfn)
24{
25	/* avoid <linux/mm.h> include hell */
26	extern unsigned long max_mapnr;
27	unsigned long pfn_offset = ARCH_PFN_OFFSET;
28
29	return pfn >= pfn_offset && (pfn - pfn_offset) < max_mapnr;
30}
31#define pfn_valid pfn_valid
32#endif
33
34#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
35
36/* memmap is virtually contiguous.  */
37#define __pfn_to_page(pfn)	(vmemmap + (pfn))
38#define __page_to_pfn(page)	(unsigned long)((page) - vmemmap)
39
40#elif defined(CONFIG_SPARSEMEM)
41/*
42 * Note: section's mem_map is encoded to reflect its start_pfn.
43 * section[i].section_mem_map == mem_map's address - start_pfn;
44 */
45#define __page_to_pfn(pg)					\
46({	const struct page *__pg = (pg);				\
47	int __sec = page_to_section(__pg);			\
48	(unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec)));	\
49})
50
51#define __pfn_to_page(pfn)				\
52({	unsigned long __pfn = (pfn);			\
53	struct mem_section *__sec = __pfn_to_section(__pfn);	\
54	__section_mem_map_addr(__sec) + __pfn;		\
55})
56#endif /* CONFIG_FLATMEM/SPARSEMEM */
57
58/*
59 * Convert a physical address to a Page Frame Number and back
60 */
61#define	__phys_to_pfn(paddr)	PHYS_PFN(paddr)
62#define	__pfn_to_phys(pfn)	PFN_PHYS(pfn)
63
64#define page_to_pfn __page_to_pfn
65#define pfn_to_page __pfn_to_page
66
67#endif /* __ASSEMBLY__ */
68
69#endif
70