xref: /linux-6.15/include/linux/memory.h (revision 6ed7ffdd)
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/node.h>
19 #include <linux/compiler.h>
20 #include <linux/mutex.h>
21 
22 #define MIN_MEMORY_BLOCK_SIZE     (1UL << SECTION_SIZE_BITS)
23 
24 struct memory_block {
25 	unsigned long start_section_nr;
26 	unsigned long end_section_nr;
27 	unsigned long state;
28 	int section_count;
29 
30 	/*
31 	 * This serializes all state change requests.  It isn't
32 	 * held during creation because the control files are
33 	 * created long after the critical areas during
34 	 * initialization.
35 	 */
36 	struct mutex state_mutex;
37 	int phys_device;		/* to which fru does this belong? */
38 	void *hw;			/* optional pointer to fw/hw data */
39 	int (*phys_callback)(struct memory_block *);
40 	struct device dev;
41 };
42 
43 int arch_get_memory_phys_device(unsigned long start_pfn);
44 
45 /* These states are exposed to userspace as text strings in sysfs */
46 #define	MEM_ONLINE		(1<<0) /* exposed to userspace */
47 #define	MEM_GOING_OFFLINE	(1<<1) /* exposed to userspace */
48 #define	MEM_OFFLINE		(1<<2) /* exposed to userspace */
49 #define	MEM_GOING_ONLINE	(1<<3)
50 #define	MEM_CANCEL_ONLINE	(1<<4)
51 #define	MEM_CANCEL_OFFLINE	(1<<5)
52 
53 struct memory_notify {
54 	unsigned long start_pfn;
55 	unsigned long nr_pages;
56 	int status_change_nid_normal;
57 	int status_change_nid_high;
58 	int status_change_nid;
59 };
60 
61 /*
62  * During pageblock isolation, count the number of pages within the
63  * range [start_pfn, start_pfn + nr_pages) which are owned by code
64  * in the notifier chain.
65  */
66 #define MEM_ISOLATE_COUNT	(1<<0)
67 
68 struct memory_isolate_notify {
69 	unsigned long start_pfn;	/* Start of range to check */
70 	unsigned int nr_pages;		/* # pages in range to check */
71 	unsigned int pages_found;	/* # pages owned found by callbacks */
72 };
73 
74 struct notifier_block;
75 struct mem_section;
76 
77 /*
78  * Priorities for the hotplug memory callback routines (stored in decreasing
79  * order in the callback chain)
80  */
81 #define SLAB_CALLBACK_PRI       1
82 #define IPC_CALLBACK_PRI        10
83 
84 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
85 static inline int memory_dev_init(void)
86 {
87 	return 0;
88 }
89 static inline int register_memory_notifier(struct notifier_block *nb)
90 {
91 	return 0;
92 }
93 static inline void unregister_memory_notifier(struct notifier_block *nb)
94 {
95 }
96 static inline int memory_notify(unsigned long val, void *v)
97 {
98 	return 0;
99 }
100 static inline int register_memory_isolate_notifier(struct notifier_block *nb)
101 {
102 	return 0;
103 }
104 static inline void unregister_memory_isolate_notifier(struct notifier_block *nb)
105 {
106 }
107 static inline int memory_isolate_notify(unsigned long val, void *v)
108 {
109 	return 0;
110 }
111 #else
112 extern int register_memory_notifier(struct notifier_block *nb);
113 extern void unregister_memory_notifier(struct notifier_block *nb);
114 extern int register_memory_isolate_notifier(struct notifier_block *nb);
115 extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
116 extern int register_new_memory(int, struct mem_section *);
117 extern int unregister_memory_section(struct mem_section *);
118 extern int memory_dev_init(void);
119 extern int remove_memory_block(unsigned long, struct mem_section *, int);
120 extern int memory_notify(unsigned long val, void *v);
121 extern int memory_isolate_notify(unsigned long val, void *v);
122 extern struct memory_block *find_memory_block_hinted(struct mem_section *,
123 							struct memory_block *);
124 extern struct memory_block *find_memory_block(struct mem_section *);
125 #define CONFIG_MEM_BLOCK_SIZE	(PAGES_PER_SECTION<<PAGE_SHIFT)
126 enum mem_add_context { BOOT, HOTPLUG };
127 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
128 
129 #ifdef CONFIG_MEMORY_HOTPLUG
130 #define hotplug_memory_notifier(fn, pri) {			\
131 	static __meminitdata struct notifier_block fn##_mem_nb =\
132 		{ .notifier_call = fn, .priority = pri };	\
133 	register_memory_notifier(&fn##_mem_nb);			\
134 }
135 #else
136 #define hotplug_memory_notifier(fn, pri) do { } while (0)
137 #endif
138 
139 /*
140  * 'struct memory_accessor' is a generic interface to provide
141  * in-kernel access to persistent memory such as i2c or SPI EEPROMs
142  */
143 struct memory_accessor {
144 	ssize_t (*read)(struct memory_accessor *, char *buf, off_t offset,
145 			size_t count);
146 	ssize_t (*write)(struct memory_accessor *, const char *buf,
147 			 off_t offset, size_t count);
148 };
149 
150 /*
151  * Kernel text modification mutex, used for code patching. Users of this lock
152  * can sleep.
153  */
154 extern struct mutex text_mutex;
155 
156 #endif /* _LINUX_MEMORY_H_ */
157