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
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
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