xref: /linux-6.15/include/linux/memory.h (revision a115bc07)
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 struct memory_block {
24 	unsigned long phys_index;
25 	unsigned long state;
26 	/*
27 	 * This serializes all state change requests.  It isn't
28 	 * held during creation because the control files are
29 	 * created long after the critical areas during
30 	 * initialization.
31 	 */
32 	struct mutex state_mutex;
33 	int phys_device;		/* to which fru does this belong? */
34 	void *hw;			/* optional pointer to fw/hw data */
35 	int (*phys_callback)(struct memory_block *);
36 	struct sys_device sysdev;
37 };
38 
39 /* These states are exposed to userspace as text strings in sysfs */
40 #define	MEM_ONLINE		(1<<0) /* exposed to userspace */
41 #define	MEM_GOING_OFFLINE	(1<<1) /* exposed to userspace */
42 #define	MEM_OFFLINE		(1<<2) /* exposed to userspace */
43 #define	MEM_GOING_ONLINE	(1<<3)
44 #define	MEM_CANCEL_ONLINE	(1<<4)
45 #define	MEM_CANCEL_OFFLINE	(1<<5)
46 
47 struct memory_notify {
48 	unsigned long start_pfn;
49 	unsigned long nr_pages;
50 	int status_change_nid;
51 };
52 
53 /*
54  * During pageblock isolation, count the number of pages within the
55  * range [start_pfn, start_pfn + nr_pages) which are owned by code
56  * in the notifier chain.
57  */
58 #define MEM_ISOLATE_COUNT	(1<<0)
59 
60 struct memory_isolate_notify {
61 	unsigned long start_pfn;	/* Start of range to check */
62 	unsigned int nr_pages;		/* # pages in range to check */
63 	unsigned int pages_found;	/* # pages owned found by callbacks */
64 };
65 
66 struct notifier_block;
67 struct mem_section;
68 
69 /*
70  * Priorities for the hotplug memory callback routines (stored in decreasing
71  * order in the callback chain)
72  */
73 #define SLAB_CALLBACK_PRI       1
74 #define IPC_CALLBACK_PRI        10
75 
76 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
77 static inline int memory_dev_init(void)
78 {
79 	return 0;
80 }
81 static inline int register_memory_notifier(struct notifier_block *nb)
82 {
83 	return 0;
84 }
85 static inline void unregister_memory_notifier(struct notifier_block *nb)
86 {
87 }
88 static inline int memory_notify(unsigned long val, void *v)
89 {
90 	return 0;
91 }
92 static inline int register_memory_isolate_notifier(struct notifier_block *nb)
93 {
94 	return 0;
95 }
96 static inline void unregister_memory_isolate_notifier(struct notifier_block *nb)
97 {
98 }
99 static inline int memory_isolate_notify(unsigned long val, void *v)
100 {
101 	return 0;
102 }
103 #else
104 extern int register_memory_notifier(struct notifier_block *nb);
105 extern void unregister_memory_notifier(struct notifier_block *nb);
106 extern int register_memory_isolate_notifier(struct notifier_block *nb);
107 extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
108 extern int register_new_memory(int, struct mem_section *);
109 extern int unregister_memory_section(struct mem_section *);
110 extern int memory_dev_init(void);
111 extern int remove_memory_block(unsigned long, struct mem_section *, int);
112 extern int memory_notify(unsigned long val, void *v);
113 extern int memory_isolate_notify(unsigned long val, void *v);
114 extern struct memory_block *find_memory_block(struct mem_section *);
115 #define CONFIG_MEM_BLOCK_SIZE	(PAGES_PER_SECTION<<PAGE_SHIFT)
116 enum mem_add_context { BOOT, HOTPLUG };
117 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
118 
119 #ifdef CONFIG_MEMORY_HOTPLUG
120 #define hotplug_memory_notifier(fn, pri) {			\
121 	static __meminitdata struct notifier_block fn##_mem_nb =\
122 		{ .notifier_call = fn, .priority = pri };	\
123 	register_memory_notifier(&fn##_mem_nb);			\
124 }
125 #else
126 #define hotplug_memory_notifier(fn, pri) do { } while (0)
127 #endif
128 
129 /*
130  * 'struct memory_accessor' is a generic interface to provide
131  * in-kernel access to persistent memory such as i2c or SPI EEPROMs
132  */
133 struct memory_accessor {
134 	ssize_t (*read)(struct memory_accessor *, char *buf, off_t offset,
135 			size_t count);
136 	ssize_t (*write)(struct memory_accessor *, const char *buf,
137 			 off_t offset, size_t count);
138 };
139 
140 /*
141  * Kernel text modification mutex, used for code patching. Users of this lock
142  * can sleep.
143  */
144 extern struct mutex text_mutex;
145 
146 #endif /* _LINUX_MEMORY_H_ */
147