1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * include/linux/memory.h - generic memory definition
4  *
5  * This is mainly for topological representation. We define the
6  * basic "struct memory_block" here, which can be embedded in per-arch
7  * definitions or NUMA information.
8  *
9  * Basic handling of the devices is done in drivers/base/memory.c
10  * and system devices are handled in drivers/base/sys.c.
11  *
12  * Memory block are exported via sysfs in the class/memory/devices/
13  * directory.
14  *
15  */
16 #ifndef _LINUX_MEMORY_H_
17 #define _LINUX_MEMORY_H_
18 
19 #include <linux/node.h>
20 #include <linux/compiler.h>
21 #include <linux/mutex.h>
22 #include <linux/notifier.h>
23 
24 #define MIN_MEMORY_BLOCK_SIZE     (1UL << SECTION_SIZE_BITS)
25 
26 /**
27  * struct memory_group - a logical group of memory blocks
28  * @nid: The node id for all memory blocks inside the memory group.
29  * @blocks: List of all memory blocks belonging to this memory group.
30  * @present_kernel_pages: Present (online) memory outside ZONE_MOVABLE of this
31  *			  memory group.
32  * @present_movable_pages: Present (online) memory in ZONE_MOVABLE of this
33  *			   memory group.
34  * @is_dynamic: The memory group type: static vs. dynamic
35  * @s.max_pages: Valid with &memory_group.is_dynamic == false. The maximum
36  *		 number of pages we'll have in this static memory group.
37  * @d.unit_pages: Valid with &memory_group.is_dynamic == true. Unit in pages
38  *		  in which memory is added/removed in this dynamic memory group.
39  *		  This granularity defines the alignment of a unit in physical
40  *		  address space; it has to be at least as big as a single
41  *		  memory block.
42  *
43  * A memory group logically groups memory blocks; each memory block
44  * belongs to at most one memory group. A memory group corresponds to
45  * a memory device, such as a DIMM or a NUMA node, which spans multiple
46  * memory blocks and might even span multiple non-contiguous physical memory
47  * ranges.
48  *
49  * Modification of members after registration is serialized by memory
50  * hot(un)plug code.
51  */
52 struct memory_group {
53 	int nid;
54 	struct list_head memory_blocks;
55 	unsigned long present_kernel_pages;
56 	unsigned long present_movable_pages;
57 	bool is_dynamic;
58 	union {
59 		struct {
60 			unsigned long max_pages;
61 		} s;
62 		struct {
63 			unsigned long unit_pages;
64 		} d;
65 	};
66 };
67 
68 struct memory_block {
69 	unsigned long start_section_nr;
70 	unsigned long state;		/* serialized by the dev->lock */
71 	int online_type;		/* for passing data to online routine */
72 	int nid;			/* NID for this memory block */
73 	/*
74 	 * The single zone of this memory block if all PFNs of this memory block
75 	 * that are System RAM (not a memory hole, not ZONE_DEVICE ranges) are
76 	 * managed by a single zone. NULL if multiple zones (including nodes)
77 	 * apply.
78 	 */
79 	struct zone *zone;
80 	struct device dev;
81 	/*
82 	 * Number of vmemmap pages. These pages
83 	 * lay at the beginning of the memory block.
84 	 */
85 	unsigned long nr_vmemmap_pages;
86 	struct memory_group *group;	/* group (if any) for this block */
87 	struct list_head group_next;	/* next block inside memory group */
88 };
89 
90 int arch_get_memory_phys_device(unsigned long start_pfn);
91 unsigned long memory_block_size_bytes(void);
92 int set_memory_block_size_order(unsigned int order);
93 
94 /* These states are exposed to userspace as text strings in sysfs */
95 #define	MEM_ONLINE		(1<<0) /* exposed to userspace */
96 #define	MEM_GOING_OFFLINE	(1<<1) /* exposed to userspace */
97 #define	MEM_OFFLINE		(1<<2) /* exposed to userspace */
98 #define	MEM_GOING_ONLINE	(1<<3)
99 #define	MEM_CANCEL_ONLINE	(1<<4)
100 #define	MEM_CANCEL_OFFLINE	(1<<5)
101 
102 struct memory_notify {
103 	unsigned long start_pfn;
104 	unsigned long nr_pages;
105 	int status_change_nid_normal;
106 	int status_change_nid;
107 };
108 
109 struct notifier_block;
110 struct mem_section;
111 
112 /*
113  * Priorities for the hotplug memory callback routines (stored in decreasing
114  * order in the callback chain)
115  */
116 #define SLAB_CALLBACK_PRI       1
117 #define IPC_CALLBACK_PRI        10
118 
119 #ifndef CONFIG_MEMORY_HOTPLUG
memory_dev_init(void)120 static inline void memory_dev_init(void)
121 {
122 	return;
123 }
register_memory_notifier(struct notifier_block * nb)124 static inline int register_memory_notifier(struct notifier_block *nb)
125 {
126 	return 0;
127 }
unregister_memory_notifier(struct notifier_block * nb)128 static inline void unregister_memory_notifier(struct notifier_block *nb)
129 {
130 }
memory_notify(unsigned long val,void * v)131 static inline int memory_notify(unsigned long val, void *v)
132 {
133 	return 0;
134 }
hotplug_memory_notifier(notifier_fn_t fn,int pri)135 static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
136 {
137 	return 0;
138 }
139 /* These aren't inline functions due to a GCC bug. */
140 #define register_hotmemory_notifier(nb)    ({ (void)(nb); 0; })
141 #define unregister_hotmemory_notifier(nb)  ({ (void)(nb); })
142 #else /* CONFIG_MEMORY_HOTPLUG */
143 extern int register_memory_notifier(struct notifier_block *nb);
144 extern void unregister_memory_notifier(struct notifier_block *nb);
145 int create_memory_block_devices(unsigned long start, unsigned long size,
146 				unsigned long vmemmap_pages,
147 				struct memory_group *group);
148 void remove_memory_block_devices(unsigned long start, unsigned long size);
149 extern void memory_dev_init(void);
150 extern int memory_notify(unsigned long val, void *v);
151 extern struct memory_block *find_memory_block(unsigned long section_nr);
152 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
153 extern int walk_memory_blocks(unsigned long start, unsigned long size,
154 			      void *arg, walk_memory_blocks_func_t func);
155 extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
156 
157 extern int memory_group_register_static(int nid, unsigned long max_pages);
158 extern int memory_group_register_dynamic(int nid, unsigned long unit_pages);
159 extern int memory_group_unregister(int mgid);
160 struct memory_group *memory_group_find_by_id(int mgid);
161 typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
162 int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
163 			       struct memory_group *excluded, void *arg);
164 #define hotplug_memory_notifier(fn, pri) ({		\
165 	static __meminitdata struct notifier_block fn##_mem_nb =\
166 		{ .notifier_call = fn, .priority = pri };\
167 	register_memory_notifier(&fn##_mem_nb);			\
168 })
169 #define register_hotmemory_notifier(nb)		register_memory_notifier(nb)
170 #define unregister_hotmemory_notifier(nb) 	unregister_memory_notifier(nb)
171 
172 #ifdef CONFIG_NUMA
173 void memory_block_add_nid(struct memory_block *mem, int nid,
174 			  enum meminit_context context);
175 #endif /* CONFIG_NUMA */
176 #endif	/* CONFIG_MEMORY_HOTPLUG */
177 
178 /*
179  * Kernel text modification mutex, used for code patching. Users of this lock
180  * can sleep.
181  */
182 extern struct mutex text_mutex;
183 
184 #endif /* _LINUX_MEMORY_H_ */
185