/* SPDX-License-Identifier: GPL-2.0 */
/*
 * include/linux/memory.h - generic memory definition
 *
 * This is mainly for topological representation. We define the
 * basic "struct memory_block" here, which can be embedded in per-arch
 * definitions or NUMA information.
 *
 * Basic handling of the devices is done in drivers/base/memory.c
 * and system devices are handled in drivers/base/sys.c.
 *
 * Memory block are exported via sysfs in the class/memory/devices/
 * directory.
 *
 */
#ifndef _LINUX_MEMORY_H_
#define _LINUX_MEMORY_H_

#include <linux/node.h>
#include <linux/compiler.h>
#include <linux/mutex.h>

#define MIN_MEMORY_BLOCK_SIZE     (1UL << SECTION_SIZE_BITS)

/**
 * struct memory_group - a logical group of memory blocks
 * @nid: The node id for all memory blocks inside the memory group.
 * @memory_blocks: List of all memory blocks belonging to this memory group.
 * @present_kernel_pages: Present (online) memory outside ZONE_MOVABLE of this
 *                        memory group.
 * @present_movable_pages: Present (online) memory in ZONE_MOVABLE of this
 *                         memory group.
 * @is_dynamic: The memory group type: static vs. dynamic
 * @s.max_pages: Valid with &memory_group.is_dynamic == false. The maximum
 *               number of pages we'll have in this static memory group.
 * @d.unit_pages: Valid with &memory_group.is_dynamic == true. Unit in pages
 *                in which memory is added/removed in this dynamic memory group.
 *                This granularity defines the alignment of a unit in physical
 *                address space; it has to be at least as big as a single
 *                memory block.
 *
 * A memory group logically groups memory blocks; each memory block
 * belongs to at most one memory group. A memory group corresponds to
 * a memory device, such as a DIMM or a NUMA node, which spans multiple
 * memory blocks and might even span multiple non-contiguous physical memory
 * ranges.
 *
 * Modification of members after registration is serialized by memory
 * hot(un)plug code.
 */
struct memory_group {
        int nid;
        struct list_head memory_blocks;
        unsigned long present_kernel_pages;
        unsigned long present_movable_pages;
        bool is_dynamic;
        union {
                struct {
                        unsigned long max_pages;
                } s;
                struct {
                        unsigned long unit_pages;
                } d;
        };
};

enum memory_block_state {
        /* These states are exposed to userspace as text strings in sysfs */
        MEM_ONLINE,             /* exposed to userspace */
        MEM_GOING_OFFLINE,      /* exposed to userspace */
        MEM_OFFLINE,            /* exposed to userspace */
        MEM_GOING_ONLINE,
        MEM_CANCEL_ONLINE,
        MEM_CANCEL_OFFLINE,
};

struct memory_block {
        unsigned long start_section_nr;
        enum memory_block_state state;  /* serialized by the dev->lock */
        int online_type;                /* for passing data to online routine */
        int nid;                        /* NID for this memory block */
        /*
         * The single zone of this memory block if all PFNs of this memory block
         * that are System RAM (not a memory hole, not ZONE_DEVICE ranges) are
         * managed by a single zone. NULL if multiple zones (including nodes)
         * apply.
         */
        struct zone *zone;
        struct device dev;
        struct vmem_altmap *altmap;
        struct memory_group *group;     /* group (if any) for this block */
        struct list_head group_next;    /* next block inside memory group */
#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
        atomic_long_t nr_hwpoison;
#endif
};

int arch_get_memory_phys_device(unsigned long start_pfn);
unsigned long memory_block_size_bytes(void);
int set_memory_block_size_order(unsigned int order);

struct memory_notify {
        unsigned long start_pfn;
        unsigned long nr_pages;
};

struct notifier_block;
struct mem_section;

/*
 * Priorities for the hotplug memory callback routines. Invoked from
 * high to low. Higher priorities correspond to higher numbers.
 */
#define DEFAULT_CALLBACK_PRI    0
#define SLAB_CALLBACK_PRI       1
#define CXL_CALLBACK_PRI        5
#define HMAT_CALLBACK_PRI       6
#define MM_COMPUTE_BATCH_PRI    10
#define CPUSET_CALLBACK_PRI     10
#define MEMTIER_HOTPLUG_PRI     100
#define KSM_CALLBACK_PRI        100

#ifndef CONFIG_MEMORY_HOTPLUG
static inline void memory_dev_init(void)
{
        return;
}
static inline int register_memory_notifier(struct notifier_block *nb)
{
        return 0;
}
static inline void unregister_memory_notifier(struct notifier_block *nb)
{
}
static inline int memory_notify(enum memory_block_state state, void *v)
{
        return 0;
}
static inline int hotplug_memory_notifier(notifier_fn_t fn, int pri)
{
        return 0;
}
static inline int memory_block_advise_max_size(unsigned long size)
{
        return -ENODEV;
}
static inline unsigned long memory_block_advised_max_size(void)
{
        return 0;
}
#else /* CONFIG_MEMORY_HOTPLUG */
extern int register_memory_notifier(struct notifier_block *nb);
extern void unregister_memory_notifier(struct notifier_block *nb);
int create_memory_block_devices(unsigned long start, unsigned long size,
                                int nid, struct vmem_altmap *altmap,
                                struct memory_group *group);
void remove_memory_block_devices(unsigned long start, unsigned long size);
extern void memory_dev_init(void);
extern int memory_notify(enum memory_block_state state, void *v);
extern struct memory_block *find_memory_block(unsigned long section_nr);
typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
extern int walk_memory_blocks(unsigned long start, unsigned long size,
                              void *arg, walk_memory_blocks_func_t func);
extern int for_each_memory_block(void *arg, walk_memory_blocks_func_t func);

extern int memory_group_register_static(int nid, unsigned long max_pages);
extern int memory_group_register_dynamic(int nid, unsigned long unit_pages);
extern int memory_group_unregister(int mgid);
struct memory_group *memory_group_find_by_id(int mgid);
typedef int (*walk_memory_groups_func_t)(struct memory_group *, void *);
int walk_dynamic_memory_groups(int nid, walk_memory_groups_func_t func,
                               struct memory_group *excluded, void *arg);
struct memory_block *find_memory_block_by_id(unsigned long block_id);
#define hotplug_memory_notifier(fn, pri) ({             \
        static __meminitdata struct notifier_block fn##_mem_nb =\
                { .notifier_call = fn, .priority = pri };\
        register_memory_notifier(&fn##_mem_nb);                 \
})

extern int sections_per_block;

static inline unsigned long memory_block_id(unsigned long section_nr)
{
        return section_nr / sections_per_block;
}

static inline unsigned long pfn_to_block_id(unsigned long pfn)
{
        return memory_block_id(pfn_to_section_nr(pfn));
}

static inline unsigned long phys_to_block_id(unsigned long phys)
{
        return pfn_to_block_id(PFN_DOWN(phys));
}

#ifdef CONFIG_NUMA
void memory_block_add_nid_early(struct memory_block *mem, int nid);
#endif /* CONFIG_NUMA */
int memory_block_advise_max_size(unsigned long size);
unsigned long memory_block_advised_max_size(void);
#endif  /* CONFIG_MEMORY_HOTPLUG */

/*
 * Kernel text modification mutex, used for code patching. Users of this lock
 * can sleep.
 */
extern struct mutex text_mutex;

#endif /* _LINUX_MEMORY_H_ */