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
pfn_valid(unsigned long pfn)23 static 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