xref: /linux-6.15/include/linux/memory.h (revision 29a36d4d)
1 /*
2  * include/linux/memory.h - generic memory definition
3  *
4  * This is mainly for topological representation. We define the
5  * basic "struct memory_block" here, which can be embedded in per-arch
6  * definitions or NUMA information.
7  *
8  * Basic handling of the devices is done in drivers/base/memory.c
9  * and system devices are handled in drivers/base/sys.c.
10  *
11  * Memory block are exported via sysfs in the class/memory/devices/
12  * directory.
13  *
14  */
15 #ifndef _LINUX_MEMORY_H_
16 #define _LINUX_MEMORY_H_
17 
18 #include <linux/sysdev.h>
19 #include <linux/node.h>
20 #include <linux/compiler.h>
21 #include <linux/mutex.h>
22 
23 #define MIN_MEMORY_BLOCK_SIZE     (1 << SECTION_SIZE_BITS)
24 
25 struct memory_block {
26 	unsigned long start_section_nr;
27 	unsigned long end_section_nr;
28 	unsigned long state;
29 	int section_count;
30 
31 	/*
32 	 * This serializes all state change requests.  It isn't
33 	 * held during creation because the control files are
34 	 * created long after the critical areas during
35 	 * initialization.
36 	 */
37 	struct mutex state_mutex;
38 	int phys_device;		/* to which fru does this belong? */
39 	void *hw;			/* optional pointer to fw/hw data */
40 	int (*phys_callback)(struct memory_block *);
41 	struct sys_device sysdev;
42 };
43 
44 int arch_get_memory_phys_device(unsigned long start_pfn);
45 
46 /* These states are exposed to userspace as text strings in sysfs */
47 #define	MEM_ONLINE		(1<<0) /* exposed to userspace */
48 #define	MEM_GOING_OFFLINE	(1<<1) /* exposed to userspace */
49 #define	MEM_OFFLINE		(1<<2) /* exposed to userspace */
50 #define	MEM_GOING_ONLINE	(1<<3)
51 #define	MEM_CANCEL_ONLINE	(1<<4)
52 #define	MEM_CANCEL_OFFLINE	(1<<5)
53 
54 struct memory_notify {
55 	unsigned long start_pfn;
56 	unsigned long nr_pages;
57 	int status_change_nid;
58 };
59 
60 /*
61  * During pageblock isolation, count the number of pages within the
62  * range [start_pfn, start_pfn + nr_pages) which are owned by code
63  * in the notifier chain.
64  */
65 #define MEM_ISOLATE_COUNT	(1<<0)
66 
67 struct memory_isolate_notify {
68 	unsigned long start_pfn;	/* Start of range to check */
69 	unsigned int nr_pages;		/* # pages in range to check */
70 	unsigned int pages_found;	/* # pages owned found by callbacks */
71 };
72 
73 struct notifier_block;
74 struct mem_section;
75 
76 /*
77  * Priorities for the hotplug memory callback routines (stored in decreasing
78  * order in the callback chain)
79  */
80 #define SLAB_CALLBACK_PRI       1
81 #define IPC_CALLBACK_PRI        10
82 
83 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
84 static inline int memory_dev_init(void)
85 {
86 	return 0;
87 }
88 static inline int register_memory_notifier(struct notifier_block *nb)
89 {
90 	return 0;
91 }
92 static inline void unregister_memory_notifier(struct notifier_block *nb)
93 {
94 }
95 static inline int memory_notify(unsigned long val, void *v)
96 {
97 	return 0;
98 }
99 static inline int register_memory_isolate_notifier(struct notifier_block *nb)
100 {
101 	return 0;
102 }
103 static inline void unregister_memory_isolate_notifier(struct notifier_block *nb)
104 {
105 }
106 static inline int memory_isolate_notify(unsigned long val, void *v)
107 {
108 	return 0;
109 }
110 #else
111 extern int register_memory_notifier(struct notifier_block *nb);
112 extern void unregister_memory_notifier(struct notifier_block *nb);
113 extern int register_memory_isolate_notifier(struct notifier_block *nb);
114 extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
115 extern int register_new_memory(int, struct mem_section *);
116 extern int unregister_memory_section(struct mem_section *);
117 extern int memory_dev_init(void);
118 extern int remove_memory_block(unsigned long, struct mem_section *, int);
119 extern int memory_notify(unsigned long val, void *v);
120 extern int memory_isolate_notify(unsigned long val, void *v);
121 extern struct memory_block *find_memory_block_hinted(struct mem_section *,
122 							struct memory_block *);
123 extern struct memory_block *find_memory_block(struct mem_section *);
124 #define CONFIG_MEM_BLOCK_SIZE	(PAGES_PER_SECTION<<PAGE_SHIFT)
125 enum mem_add_context { BOOT, HOTPLUG };
126 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
127 
128 #ifdef CONFIG_MEMORY_HOTPLUG
129 #define hotplug_memory_notifier(fn, pri) {			\
130 	static __meminitdata struct notifier_block fn##_mem_nb =\
131 		{ .notifier_call = fn, .priority = pri };	\
132 	register_memory_notifier(&fn##_mem_nb);			\
133 }
134 #else
135 #define hotplug_memory_notifier(fn, pri) do { } while (0)
136 #endif
137 
138 /*
139  * 'struct memory_accessor' is a generic interface to provide
140  * in-kernel access to persistent memory such as i2c or SPI EEPROMs
141  */
142 struct memory_accessor {
143 	ssize_t (*read)(struct memory_accessor *, char *buf, off_t offset,
144 			size_t count);
145 	ssize_t (*write)(struct memory_accessor *, const char *buf,
146 			 off_t offset, size_t count);
147 };
148 
149 /*
150  * Kernel text modification mutex, used for code patching. Users of this lock
151  * can sleep.
152  */
153 extern struct mutex text_mutex;
154 
155 #endif /* _LINUX_MEMORY_H_ */
156