1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef __LINUX_PAGE_EXT_H |
3 | #define __LINUX_PAGE_EXT_H |
4 | |
5 | #include <linux/types.h> |
6 | #include <linux/stacktrace.h> |
7 | #include <linux/stackdepot.h> |
8 | |
9 | struct pglist_data; |
10 | |
11 | #ifdef CONFIG_PAGE_EXTENSION |
12 | /** |
13 | * struct page_ext_operations - per page_ext client operations |
14 | * @offset: Offset to the client's data within page_ext. Offset is returned to |
15 | * the client by page_ext_init. |
16 | * @size: The size of the client data within page_ext. |
17 | * @need: Function that returns true if client requires page_ext. |
18 | * @init: (optional) Called to initialize client once page_exts are allocated. |
19 | * @need_shared_flags: True when client is using shared page_ext->flags |
20 | * field. |
21 | * |
22 | * Each Page Extension client must define page_ext_operations in |
23 | * page_ext_ops array. |
24 | */ |
25 | struct page_ext_operations { |
26 | size_t offset; |
27 | size_t size; |
28 | bool (*need)(void); |
29 | void (*init)(void); |
30 | bool need_shared_flags; |
31 | }; |
32 | |
33 | /* |
34 | * The page_ext_flags users must set need_shared_flags to true. |
35 | */ |
36 | enum page_ext_flags { |
37 | PAGE_EXT_OWNER, |
38 | PAGE_EXT_OWNER_ALLOCATED, |
39 | #if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT) |
40 | PAGE_EXT_YOUNG, |
41 | PAGE_EXT_IDLE, |
42 | #endif |
43 | }; |
44 | |
45 | /* |
46 | * Page Extension can be considered as an extended mem_map. |
47 | * A page_ext page is associated with every page descriptor. The |
48 | * page_ext helps us add more information about the page. |
49 | * All page_ext are allocated at boot or memory hotplug event, |
50 | * then the page_ext for pfn always exists. |
51 | */ |
52 | struct page_ext { |
53 | unsigned long flags; |
54 | }; |
55 | |
56 | extern bool early_page_ext; |
57 | extern unsigned long page_ext_size; |
58 | extern void pgdat_page_ext_init(struct pglist_data *pgdat); |
59 | |
60 | static inline bool early_page_ext_enabled(void) |
61 | { |
62 | return early_page_ext; |
63 | } |
64 | |
65 | #ifdef CONFIG_SPARSEMEM |
66 | static inline void page_ext_init_flatmem(void) |
67 | { |
68 | } |
69 | extern void page_ext_init(void); |
70 | static inline void page_ext_init_flatmem_late(void) |
71 | { |
72 | } |
73 | #else |
74 | extern void page_ext_init_flatmem(void); |
75 | extern void page_ext_init_flatmem_late(void); |
76 | static inline void page_ext_init(void) |
77 | { |
78 | } |
79 | #endif |
80 | |
81 | extern struct page_ext *page_ext_get(struct page *page); |
82 | extern void page_ext_put(struct page_ext *page_ext); |
83 | |
84 | static inline void *page_ext_data(struct page_ext *page_ext, |
85 | struct page_ext_operations *ops) |
86 | { |
87 | return (void *)(page_ext) + ops->offset; |
88 | } |
89 | |
90 | static inline struct page_ext *page_ext_next(struct page_ext *curr) |
91 | { |
92 | void *next = curr; |
93 | next += page_ext_size; |
94 | return next; |
95 | } |
96 | |
97 | #else /* !CONFIG_PAGE_EXTENSION */ |
98 | struct page_ext; |
99 | |
100 | static inline bool early_page_ext_enabled(void) |
101 | { |
102 | return false; |
103 | } |
104 | |
105 | static inline void pgdat_page_ext_init(struct pglist_data *pgdat) |
106 | { |
107 | } |
108 | |
109 | static inline void page_ext_init(void) |
110 | { |
111 | } |
112 | |
113 | static inline void page_ext_init_flatmem_late(void) |
114 | { |
115 | } |
116 | |
117 | static inline void page_ext_init_flatmem(void) |
118 | { |
119 | } |
120 | |
121 | static inline struct page_ext *page_ext_get(struct page *page) |
122 | { |
123 | return NULL; |
124 | } |
125 | |
126 | static inline void page_ext_put(struct page_ext *page_ext) |
127 | { |
128 | } |
129 | #endif /* CONFIG_PAGE_EXTENSION */ |
130 | #endif /* __LINUX_PAGE_EXT_H */ |
131 | |