xref: /linux-6.15/include/linux/memory.h (revision e756bc56)
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 #include <linux/notifier.h>
22 
23 #define MIN_MEMORY_BLOCK_SIZE     (1UL << SECTION_SIZE_BITS)
24 
25 struct memory_block {
26 	unsigned long start_section_nr;
27 	unsigned long end_section_nr;
28 	unsigned long state;		/* serialized by the dev->lock */
29 	int section_count;		/* serialized by mem_sysfs_mutex */
30 	int online_type;		/* for passing data to online routine */
31 	int phys_device;		/* to which fru does this belong? */
32 	void *hw;			/* optional pointer to fw/hw data */
33 	int (*phys_callback)(struct memory_block *);
34 	struct device dev;
35 };
36 
37 int arch_get_memory_phys_device(unsigned long start_pfn);
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_normal;
51 	int status_change_nid_high;
52 	int status_change_nid;
53 };
54 
55 /*
56  * During pageblock isolation, count the number of pages within the
57  * range [start_pfn, start_pfn + nr_pages) which are owned by code
58  * in the notifier chain.
59  */
60 #define MEM_ISOLATE_COUNT	(1<<0)
61 
62 struct memory_isolate_notify {
63 	unsigned long start_pfn;	/* Start of range to check */
64 	unsigned int nr_pages;		/* # pages in range to check */
65 	unsigned int pages_found;	/* # pages owned found by callbacks */
66 };
67 
68 struct notifier_block;
69 struct mem_section;
70 
71 /*
72  * Priorities for the hotplug memory callback routines (stored in decreasing
73  * order in the callback chain)
74  */
75 #define SLAB_CALLBACK_PRI       1
76 #define IPC_CALLBACK_PRI        10
77 
78 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
79 static inline int memory_dev_init(void)
80 {
81 	return 0;
82 }
83 static inline int register_memory_notifier(struct notifier_block *nb)
84 {
85 	return 0;
86 }
87 static inline void unregister_memory_notifier(struct notifier_block *nb)
88 {
89 }
90 static inline int memory_notify(unsigned long val, void *v)
91 {
92 	return 0;
93 }
94 static inline int register_memory_isolate_notifier(struct notifier_block *nb)
95 {
96 	return 0;
97 }
98 static inline void unregister_memory_isolate_notifier(struct notifier_block *nb)
99 {
100 }
101 static inline int memory_isolate_notify(unsigned long val, void *v)
102 {
103 	return 0;
104 }
105 #else
106 extern int register_memory_notifier(struct notifier_block *nb);
107 extern void unregister_memory_notifier(struct notifier_block *nb);
108 extern int register_memory_isolate_notifier(struct notifier_block *nb);
109 extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
110 extern int register_new_memory(int, struct mem_section *);
111 #ifdef CONFIG_MEMORY_HOTREMOVE
112 extern int unregister_memory_section(struct mem_section *);
113 #endif
114 extern int memory_dev_init(void);
115 extern int memory_notify(unsigned long val, void *v);
116 extern int memory_isolate_notify(unsigned long val, void *v);
117 extern struct memory_block *find_memory_block_hinted(struct mem_section *,
118 							struct memory_block *);
119 extern struct memory_block *find_memory_block(struct mem_section *);
120 #define CONFIG_MEM_BLOCK_SIZE	(PAGES_PER_SECTION<<PAGE_SHIFT)
121 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
122 
123 #ifdef CONFIG_MEMORY_HOTPLUG
124 #define hotplug_memory_notifier(fn, pri) ({		\
125 	static __meminitdata struct notifier_block fn##_mem_nb =\
126 		{ .notifier_call = fn, .priority = pri };\
127 	register_memory_notifier(&fn##_mem_nb);			\
128 })
129 #define register_hotmemory_notifier(nb)		register_memory_notifier(nb)
130 #define unregister_hotmemory_notifier(nb) 	unregister_memory_notifier(nb)
131 #else
132 #define hotplug_memory_notifier(fn, pri)	({ 0; })
133 /* These aren't inline functions due to a GCC bug. */
134 #define register_hotmemory_notifier(nb)    ({ (void)(nb); 0; })
135 #define unregister_hotmemory_notifier(nb)  ({ (void)(nb); })
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