include/linux/memory.h

   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 struct memory_block {
  27         unsigned long start_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         struct device dev;
  33         int nid;                        /* NID for this memory block */
  34 };
  35
  36 int arch_get_memory_phys_device(unsigned long start_pfn);
  37 unsigned long memory_block_size_bytes(void);
  38 int set_memory_block_size_order(unsigned int order);
  39
  40 /* These states are exposed to userspace as text strings in sysfs */
  41 #define MEM_ONLINE              (1<<0) /* exposed to userspace */
  42 #define MEM_GOING_OFFLINE       (1<<1) /* exposed to userspace */
  43 #define MEM_OFFLINE             (1<<2) /* exposed to userspace */
  44 #define MEM_GOING_ONLINE        (1<<3)
  45 #define MEM_CANCEL_ONLINE       (1<<4)
  46 #define MEM_CANCEL_OFFLINE      (1<<5)
  47
  48 struct memory_notify {
  49         unsigned long start_pfn;
  50         unsigned long nr_pages;
  51         int status_change_nid_normal;
  52         int status_change_nid_high;
  53         int status_change_nid;
  54 };
  55
  56 struct notifier_block;
  57 struct mem_section;
  58
  59 /*
  60  * Priorities for the hotplug memory callback routines (stored in decreasing
  61  * order in the callback chain)
  62  */
  63 #define SLAB_CALLBACK_PRI       1
  64 #define IPC_CALLBACK_PRI        10
  65
  66 #ifndef CONFIG_MEMORY_HOTPLUG_SPARSE
  67 static inline void memory_dev_init(void)
  68 {
  69         return;
  70 }
  71 static inline int register_memory_notifier(struct notifier_block *nb)
  72 {
  73         return 0;
  74 }
  75 static inline void unregister_memory_notifier(struct notifier_block *nb)
  76 {
  77 }
  78 static inline int memory_notify(unsigned long val, void *v)
  79 {
  80         return 0;
  81 }
  82 #else
  83 extern int register_memory_notifier(struct notifier_block *nb);
  84 extern void unregister_memory_notifier(struct notifier_block *nb);
  85 int create_memory_block_devices(unsigned long start, unsigned long size);
  86 void remove_memory_block_devices(unsigned long start, unsigned long size);
  87 extern void memory_dev_init(void);
  88 extern int memory_notify(unsigned long val, void *v);
  89 extern struct memory_block *find_memory_block(struct mem_section *);
  90 typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
  91 extern int walk_memory_blocks(unsigned long start, unsigned long size,
  92                               void *arg, walk_memory_blocks_func_t func);
  93 extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);
  94 #define CONFIG_MEM_BLOCK_SIZE   (PAGES_PER_SECTION<<PAGE_SHIFT)
  95 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
  96
  97 #ifdef CONFIG_MEMORY_HOTPLUG
  98 #define hotplug_memory_notifier(fn, pri) ({             \
  99         static __meminitdata struct notifier_block fn##_mem_nb =\
 100                 { .notifier_call = fn, .priority = pri };\
 101         register_memory_notifier(&fn##_mem_nb);                 \
 102 })
 103 #define register_hotmemory_notifier(nb)         register_memory_notifier(nb)
 104 #define unregister_hotmemory_notifier(nb)       unregister_memory_notifier(nb)
 105 #else
 106 #define hotplug_memory_notifier(fn, pri)        ({ 0; })
 107 /* These aren't inline functions due to a GCC bug. */
 108 #define register_hotmemory_notifier(nb)    ({ (void)(nb); 0; })
 109 #define unregister_hotmemory_notifier(nb)  ({ (void)(nb); })
 110 #endif
 111
 112 /*
 113  * Kernel text modification mutex, used for code patching. Users of this lock
 114  * can sleep.
 115  */
 116 extern struct mutex text_mutex;
 117
 118 #endif /* _LINUX_MEMORY_H_ */