xref: /linux/include/asm-generic/memory_model.h (revision 95298d63c67673c654c08952672d016212b26054)
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 #if defined(CONFIG_FLATMEM)
10 
11 #ifndef ARCH_PFN_OFFSET
12 #define ARCH_PFN_OFFSET		(0UL)
13 #endif
14 
15 #elif defined(CONFIG_DISCONTIGMEM)
16 
17 #ifndef arch_pfn_to_nid
18 #define arch_pfn_to_nid(pfn)	pfn_to_nid(pfn)
19 #endif
20 
21 #ifndef arch_local_page_offset
22 #define arch_local_page_offset(pfn, nid)	\
23 	((pfn) - NODE_DATA(nid)->node_start_pfn)
24 #endif
25 
26 #endif /* CONFIG_DISCONTIGMEM */
27 
28 /*
29  * supports 3 memory models.
30  */
31 #if defined(CONFIG_FLATMEM)
32 
33 #define __pfn_to_page(pfn)	(mem_map + ((pfn) - ARCH_PFN_OFFSET))
34 #define __page_to_pfn(page)	((unsigned long)((page) - mem_map) + \
35 				 ARCH_PFN_OFFSET)
36 #elif defined(CONFIG_DISCONTIGMEM)
37 
38 #define __pfn_to_page(pfn)			\
39 ({	unsigned long __pfn = (pfn);		\
40 	unsigned long __nid = arch_pfn_to_nid(__pfn);  \
41 	NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\
42 })
43 
44 #define __page_to_pfn(pg)						\
45 ({	const struct page *__pg = (pg);					\
46 	struct pglist_data *__pgdat = NODE_DATA(page_to_nid(__pg));	\
47 	(unsigned long)(__pg - __pgdat->node_mem_map) +			\
48 	 __pgdat->node_start_pfn;					\
49 })
50 
51 #elif defined(CONFIG_SPARSEMEM_VMEMMAP)
52 
53 /* memmap is virtually contiguous.  */
54 #define __pfn_to_page(pfn)	(vmemmap + (pfn))
55 #define __page_to_pfn(page)	(unsigned long)((page) - vmemmap)
56 
57 #elif defined(CONFIG_SPARSEMEM)
58 /*
59  * Note: section's mem_map is encoded to reflect its start_pfn.
60  * section[i].section_mem_map == mem_map's address - start_pfn;
61  */
62 #define __page_to_pfn(pg)					\
63 ({	const struct page *__pg = (pg);				\
64 	int __sec = page_to_section(__pg);			\
65 	(unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec)));	\
66 })
67 
68 #define __pfn_to_page(pfn)				\
69 ({	unsigned long __pfn = (pfn);			\
70 	struct mem_section *__sec = __pfn_to_section(__pfn);	\
71 	__section_mem_map_addr(__sec) + __pfn;		\
72 })
73 #endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */
74 
75 /*
76  * Convert a physical address to a Page Frame Number and back
77  */
78 #define	__phys_to_pfn(paddr)	PHYS_PFN(paddr)
79 #define	__pfn_to_phys(pfn)	PFN_PHYS(pfn)
80 
81 #define page_to_pfn __page_to_pfn
82 #define pfn_to_page __pfn_to_page
83 
84 #endif /* __ASSEMBLY__ */
85 
86 #endif
87