/* SPDX-License-Identifier: GPL-2.0 */
#ifndef MM_SLAB_H
#define MM_SLAB_H

#include <linux/reciprocal_div.h>
#include <linux/list_lru.h>
#include <linux/local_lock.h>
#include <linux/random.h>
#include <linux/kobject.h>
#include <linux/sched/mm.h>
#include <linux/memcontrol.h>
#include <linux/kfence.h>
#include <linux/kasan.h>

/*
 * Internal slab definitions
 */

#ifdef CONFIG_64BIT
# ifdef system_has_cmpxchg128
# define system_has_freelist_aba()      system_has_cmpxchg128()
# define try_cmpxchg_freelist           try_cmpxchg128
# endif
typedef u128 freelist_full_t;
#else /* CONFIG_64BIT */
# ifdef system_has_cmpxchg64
# define system_has_freelist_aba()      system_has_cmpxchg64()
# define try_cmpxchg_freelist           try_cmpxchg64
# endif
typedef u64 freelist_full_t;
#endif /* CONFIG_64BIT */

#if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
#undef system_has_freelist_aba
#endif

/*
 * Freelist pointer and counter to cmpxchg together, avoids the typical ABA
 * problems with cmpxchg of just a pointer.
 */
struct freelist_counters {
        union {
                struct {
                        void *freelist;
                        union {
                                unsigned long counters;
                                struct {
                                        unsigned inuse:16;
                                        unsigned objects:15;
                                        /*
                                         * If slab debugging is enabled then the
                                         * frozen bit can be reused to indicate
                                         * that the slab was corrupted
                                         */
                                        unsigned frozen:1;
#ifdef CONFIG_64BIT
                                        /*
                                         * Some optimizations use free bits in 'counters' field
                                         * to save memory. In case ->stride field is not available,
                                         * such optimizations are disabled.
                                         */
                                        unsigned int stride;
#endif
                                };
                        };
                };
#ifdef system_has_freelist_aba
                freelist_full_t freelist_counters;
#endif
        };
};

/* Reuses the bits in struct page */
struct slab {
        memdesc_flags_t flags;

        struct kmem_cache *slab_cache;
        union {
                struct {
                        struct list_head slab_list;
                        /* Double-word boundary */
                        struct freelist_counters;
                };
                struct rcu_head rcu_head;
        };

        unsigned int __page_type;
        atomic_t __page_refcount;
#ifdef CONFIG_SLAB_OBJ_EXT
        unsigned long obj_exts;
#endif
};

#define SLAB_MATCH(pg, sl)                                              \
        static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
SLAB_MATCH(flags, flags);
SLAB_MATCH(compound_head, slab_cache);  /* Ensure bit 0 is clear */
SLAB_MATCH(_refcount, __page_refcount);
#ifdef CONFIG_MEMCG
SLAB_MATCH(memcg_data, obj_exts);
#elif defined(CONFIG_SLAB_OBJ_EXT)
SLAB_MATCH(_unused_slab_obj_exts, obj_exts);
#endif
#undef SLAB_MATCH
static_assert(sizeof(struct slab) <= sizeof(struct page));
#if defined(system_has_freelist_aba)
static_assert(IS_ALIGNED(offsetof(struct slab, freelist), sizeof(struct freelist_counters)));
#endif

/**
 * slab_folio - The folio allocated for a slab
 * @s: The slab.
 *
 * Slabs are allocated as folios that contain the individual objects and are
 * using some fields in the first struct page of the folio - those fields are
 * now accessed by struct slab. It is occasionally necessary to convert back to
 * a folio in order to communicate with the rest of the mm.  Please use this
 * helper function instead of casting yourself, as the implementation may change
 * in the future.
 */
#define slab_folio(s)           (_Generic((s),                          \
        const struct slab *:    (const struct folio *)s,                \
        struct slab *:          (struct folio *)s))

/**
 * page_slab - Converts from struct page to its slab.
 * @page: A page which may or may not belong to a slab.
 *
 * Return: The slab which contains this page or NULL if the page does
 * not belong to a slab.  This includes pages returned from large kmalloc.
 */
static inline struct slab *page_slab(const struct page *page)
{
        unsigned long head;

        head = READ_ONCE(page->compound_head);
        if (head & 1)
                page = (struct page *)(head - 1);
        if (data_race(page->page_type >> 24) != PGTY_slab)
                page = NULL;

        return (struct slab *)page;
}

/**
 * slab_page - The first struct page allocated for a slab
 * @s: The slab.
 *
 * A convenience wrapper for converting slab to the first struct page of the
 * underlying folio, to communicate with code not yet converted to folio or
 * struct slab.
 */
#define slab_page(s) folio_page(slab_folio(s), 0)

static inline void *slab_address(const struct slab *slab)
{
        return folio_address(slab_folio(slab));
}

static inline int slab_nid(const struct slab *slab)
{
        return memdesc_nid(slab->flags);
}

static inline pg_data_t *slab_pgdat(const struct slab *slab)
{
        return NODE_DATA(slab_nid(slab));
}

static inline struct slab *virt_to_slab(const void *addr)
{
        return page_slab(virt_to_page(addr));
}

static inline int slab_order(const struct slab *slab)
{
        return folio_order(slab_folio(slab));
}

static inline size_t slab_size(const struct slab *slab)
{
        return PAGE_SIZE << slab_order(slab);
}

/*
 * Word size structure that can be atomically updated or read and that
 * contains both the order and the number of objects that a slab of the
 * given order would contain.
 */
struct kmem_cache_order_objects {
        unsigned int x;
};

/*
 * Slab cache management.
 */
struct kmem_cache {
        struct slub_percpu_sheaves __percpu *cpu_sheaves;
        /* Used for retrieving partial slabs, etc. */
        slab_flags_t flags;
        unsigned long min_partial;
        unsigned int size;              /* Object size including metadata */
        unsigned int object_size;       /* Object size without metadata */
        struct reciprocal_value reciprocal_size;
        unsigned int offset;            /* Free pointer offset */
        unsigned int sheaf_capacity;
        struct kmem_cache_order_objects oo;

        /* Allocation and freeing of slabs */
        struct kmem_cache_order_objects min;
        gfp_t allocflags;               /* gfp flags to use on each alloc */
        int refcount;                   /* Refcount for slab cache destroy */
        void (*ctor)(void *object);     /* Object constructor */
        unsigned int inuse;             /* Offset to metadata */
        unsigned int align;             /* Alignment */
        unsigned int red_left_pad;      /* Left redzone padding size */
        const char *name;               /* Name (only for display!) */
        struct list_head list;          /* List of slab caches */
#ifdef CONFIG_SYSFS
        struct kobject kobj;            /* For sysfs */
#endif
#ifdef CONFIG_SLAB_FREELIST_HARDENED
        unsigned long random;
#endif

#ifdef CONFIG_NUMA
        /*
         * Defragmentation by allocating from a remote node.
         */
        unsigned int remote_node_defrag_ratio;
#endif

#ifdef CONFIG_SLAB_FREELIST_RANDOM
        unsigned int *random_seq;
#endif

#ifdef CONFIG_KASAN_GENERIC
        struct kasan_cache kasan_info;
#endif

#ifdef CONFIG_HARDENED_USERCOPY
        unsigned int useroffset;        /* Usercopy region offset */
        unsigned int usersize;          /* Usercopy region size */
#endif

#ifdef CONFIG_SLUB_STATS
        struct kmem_cache_stats __percpu *cpu_stats;
#endif

        struct kmem_cache_node *node[MAX_NUMNODES];
};

/*
 * Every cache has !NULL s->cpu_sheaves but they may point to the
 * bootstrap_sheaf temporarily during init, or permanently for the boot caches
 * and caches with debugging enabled, or all caches with CONFIG_SLUB_TINY. This
 * helper distinguishes whether cache has real non-bootstrap sheaves.
 */
static inline bool cache_has_sheaves(struct kmem_cache *s)
{
        /* Test CONFIG_SLUB_TINY for code elimination purposes */
        return !IS_ENABLED(CONFIG_SLUB_TINY) && s->sheaf_capacity;
}

#if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
#define SLAB_SUPPORTS_SYSFS 1
void sysfs_slab_unlink(struct kmem_cache *s);
void sysfs_slab_release(struct kmem_cache *s);
int sysfs_slab_alias(struct kmem_cache *s, const char *name);
#else
static inline void sysfs_slab_unlink(struct kmem_cache *s) { }
static inline void sysfs_slab_release(struct kmem_cache *s) { }
static inline int sysfs_slab_alias(struct kmem_cache *s, const char *name)
                                                        { return 0; }
#endif

void *fixup_red_left(struct kmem_cache *s, void *p);

static inline void *nearest_obj(struct kmem_cache *cache,
                                const struct slab *slab, void *x)
{
        void *object = x - (x - slab_address(slab)) % cache->size;
        void *last_object = slab_address(slab) +
                (slab->objects - 1) * cache->size;
        void *result = (unlikely(object > last_object)) ? last_object : object;

        result = fixup_red_left(cache, result);
        return result;
}

/* Determine object index from a given position */
static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
                                          void *addr, const void *obj)
{
        return reciprocal_divide(kasan_reset_tag(obj) - addr,
                                 cache->reciprocal_size);
}

static inline unsigned int obj_to_index(const struct kmem_cache *cache,
                                        const struct slab *slab, const void *obj)
{
        if (is_kfence_address(obj))
                return 0;
        return __obj_to_index(cache, slab_address(slab), obj);
}

static inline int objs_per_slab(const struct kmem_cache *cache,
                                const struct slab *slab)
{
        return slab->objects;
}

/*
 * State of the slab allocator.
 *
 * This is used to describe the states of the allocator during bootup.
 * Allocators use this to gradually bootstrap themselves. Most allocators
 * have the problem that the structures used for managing slab caches are
 * allocated from slab caches themselves.
 */
enum slab_state {
        DOWN,                   /* No slab functionality yet */
        PARTIAL,                /* SLUB: kmem_cache_node available */
        UP,                     /* Slab caches usable but not all extras yet */
        FULL                    /* Everything is working */
};

extern enum slab_state slab_state;

/* The slab cache mutex protects the management structures during changes */
extern struct mutex slab_mutex;

/* The list of all slab caches on the system */
extern struct list_head slab_caches;

/* The slab cache that manages slab cache information */
extern struct kmem_cache *kmem_cache;

/* A table of kmalloc cache names and sizes */
extern const struct kmalloc_info_struct {
        const char *name[NR_KMALLOC_TYPES];
        unsigned int size;
} kmalloc_info[];

/* Kmalloc array related functions */
void setup_kmalloc_cache_index_table(void);
void create_kmalloc_caches(void);

extern u8 kmalloc_size_index[24];

static inline unsigned int size_index_elem(unsigned int bytes)
{
        return (bytes - 1) / 8;
}

/*
 * Find the kmem_cache structure that serves a given size of
 * allocation
 *
 * This assumes size is larger than zero and not larger than
 * KMALLOC_MAX_CACHE_SIZE and the caller must check that.
 */
static inline struct kmem_cache *
kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller)
{
        unsigned int index;

        if (!b)
                b = &kmalloc_caches[kmalloc_type(flags, caller)];
        if (size <= 192)
                index = kmalloc_size_index[size_index_elem(size)];
        else
                index = fls(size - 1);

        return (*b)[index];
}

gfp_t kmalloc_fix_flags(gfp_t flags);

/* Functions provided by the slab allocators */
int do_kmem_cache_create(struct kmem_cache *s, const char *name,
                         unsigned int size, struct kmem_cache_args *args,
                         slab_flags_t flags);

void __init kmem_cache_init(void);
extern void create_boot_cache(struct kmem_cache *, const char *name,
                        unsigned int size, slab_flags_t flags,
                        unsigned int useroffset, unsigned int usersize);

int slab_unmergeable(struct kmem_cache *s);
bool slab_args_unmergeable(struct kmem_cache_args *args, slab_flags_t flags);

slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name);

static inline bool is_kmalloc_cache(struct kmem_cache *s)
{
        return (s->flags & SLAB_KMALLOC);
}

static inline bool is_kmalloc_normal(struct kmem_cache *s)
{
        if (!is_kmalloc_cache(s))
                return false;
        return !(s->flags & (SLAB_CACHE_DMA|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT));
}

bool __kfree_rcu_sheaf(struct kmem_cache *s, void *obj);
void flush_all_rcu_sheaves(void);
void flush_rcu_sheaves_on_cache(struct kmem_cache *s);

#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
                         SLAB_CACHE_DMA32 | SLAB_PANIC | \
                         SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS | \
                         SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
                         SLAB_TEMPORARY | SLAB_ACCOUNT | \
                         SLAB_NO_USER_FLAGS | SLAB_KMALLOC | SLAB_NO_MERGE)

#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
                          SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)

#define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS)

bool __kmem_cache_empty(struct kmem_cache *);
int __kmem_cache_shutdown(struct kmem_cache *);
void __kmem_cache_release(struct kmem_cache *);
int __kmem_cache_shrink(struct kmem_cache *);
void slab_kmem_cache_release(struct kmem_cache *);

struct seq_file;
struct file;

struct slabinfo {
        unsigned long active_objs;
        unsigned long num_objs;
        unsigned long active_slabs;
        unsigned long num_slabs;
        unsigned long shared_avail;
        unsigned int limit;
        unsigned int batchcount;
        unsigned int shared;
        unsigned int objects_per_slab;
        unsigned int cache_order;
};

void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);

#ifdef CONFIG_SLUB_DEBUG
#ifdef CONFIG_SLUB_DEBUG_ON
DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
#else
DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
#endif
extern void print_tracking(struct kmem_cache *s, void *object);
long validate_slab_cache(struct kmem_cache *s);
static inline bool __slub_debug_enabled(void)
{
        return static_branch_unlikely(&slub_debug_enabled);
}
#else
static inline void print_tracking(struct kmem_cache *s, void *object)
{
}
static inline bool __slub_debug_enabled(void)
{
        return false;
}
#endif

/*
 * Returns true if any of the specified slab_debug flags is enabled for the
 * cache. Use only for flags parsed by setup_slub_debug() as it also enables
 * the static key.
 */
static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
{
        if (IS_ENABLED(CONFIG_SLUB_DEBUG))
                VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
        if (__slub_debug_enabled())
                return s->flags & flags;
        return false;
}

#if IS_ENABLED(CONFIG_SLUB_DEBUG) && IS_ENABLED(CONFIG_KUNIT)
bool slab_in_kunit_test(void);
#else
static inline bool slab_in_kunit_test(void) { return false; }
#endif

/*
 * slub is about to manipulate internal object metadata.  This memory lies
 * outside the range of the allocated object, so accessing it would normally
 * be reported by kasan as a bounds error.  metadata_access_enable() is used
 * to tell kasan that these accesses are OK.
 */
static inline void metadata_access_enable(void)
{
        kasan_disable_current();
        kmsan_disable_current();
}

static inline void metadata_access_disable(void)
{
        kmsan_enable_current();
        kasan_enable_current();
}

#ifdef CONFIG_SLAB_OBJ_EXT

/*
 * slab_obj_exts - get the pointer to the slab object extension vector
 * associated with a slab.
 * @slab: a pointer to the slab struct
 *
 * Returns the address of the object extension vector associated with the slab,
 * or zero if no such vector has been associated yet.
 * Do not dereference the return value directly; use get/put_slab_obj_exts()
 * pair and slab_obj_ext() to access individual elements.
 *
 * Example usage:
 *
 * obj_exts = slab_obj_exts(slab);
 * if (obj_exts) {
 *         get_slab_obj_exts(obj_exts);
 *         obj_ext = slab_obj_ext(slab, obj_exts, obj_to_index(s, slab, obj));
 *         // do something with obj_ext
 *         put_slab_obj_exts(obj_exts);
 * }
 *
 * Note that the get/put semantics does not involve reference counting.
 * Instead, it updates kasan/kmsan depth so that accesses to slabobj_ext
 * won't be reported as access violations.
 */
static inline unsigned long slab_obj_exts(struct slab *slab)
{
        unsigned long obj_exts = READ_ONCE(slab->obj_exts);

#ifdef CONFIG_MEMCG
        /*
         * obj_exts should be either NULL, a valid pointer with
         * MEMCG_DATA_OBJEXTS bit set or be equal to OBJEXTS_ALLOC_FAIL.
         */
        VM_BUG_ON_PAGE(obj_exts && !(obj_exts & MEMCG_DATA_OBJEXTS) &&
                       obj_exts != OBJEXTS_ALLOC_FAIL, slab_page(slab));
        VM_BUG_ON_PAGE(obj_exts & MEMCG_DATA_KMEM, slab_page(slab));
#endif

        return obj_exts & ~OBJEXTS_FLAGS_MASK;
}

static inline void get_slab_obj_exts(unsigned long obj_exts)
{
        VM_WARN_ON_ONCE(!obj_exts);
        metadata_access_enable();
}

static inline void put_slab_obj_exts(unsigned long obj_exts)
{
        metadata_access_disable();
}

#ifdef CONFIG_64BIT
static inline void slab_set_stride(struct slab *slab, unsigned int stride)
{
        slab->stride = stride;
}
static inline unsigned int slab_get_stride(struct slab *slab)
{
        return slab->stride;
}
#else
static inline void slab_set_stride(struct slab *slab, unsigned int stride)
{
        VM_WARN_ON_ONCE(stride != sizeof(struct slabobj_ext));
}
static inline unsigned int slab_get_stride(struct slab *slab)
{
        return sizeof(struct slabobj_ext);
}
#endif

/*
 * slab_obj_ext - get the pointer to the slab object extension metadata
 * associated with an object in a slab.
 * @slab: a pointer to the slab struct
 * @obj_exts: a pointer to the object extension vector
 * @index: an index of the object
 *
 * Returns a pointer to the object extension associated with the object.
 * Must be called within a section covered by get/put_slab_obj_exts().
 */
static inline struct slabobj_ext *slab_obj_ext(struct slab *slab,
                                               unsigned long obj_exts,
                                               unsigned int index)
{
        struct slabobj_ext *obj_ext;

        VM_WARN_ON_ONCE(obj_exts != slab_obj_exts(slab));

        obj_ext = (struct slabobj_ext *)(obj_exts +
                                         slab_get_stride(slab) * index);
        return kasan_reset_tag(obj_ext);
}

int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s,
                        gfp_t gfp, bool new_slab);

#else /* CONFIG_SLAB_OBJ_EXT */

static inline unsigned long slab_obj_exts(struct slab *slab)
{
        return 0;
}

static inline struct slabobj_ext *slab_obj_ext(struct slab *slab,
                                               unsigned long obj_exts,
                                               unsigned int index)
{
        return NULL;
}

static inline void slab_set_stride(struct slab *slab, unsigned int stride) { }
static inline unsigned int slab_get_stride(struct slab *slab) { return 0; }


#endif /* CONFIG_SLAB_OBJ_EXT */

static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
{
        return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
                NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
}

#ifdef CONFIG_MEMCG
bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
                                  gfp_t flags, size_t size, void **p);
void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
                            void **p, int objects, unsigned long obj_exts);
#endif

void kvfree_rcu_cb(struct rcu_head *head);

static inline unsigned int large_kmalloc_order(const struct page *page)
{
        return page[1].flags.f & 0xff;
}

static inline size_t large_kmalloc_size(const struct page *page)
{
        return PAGE_SIZE << large_kmalloc_order(page);
}

#ifdef CONFIG_SLUB_DEBUG
void dump_unreclaimable_slab(void);
#else
static inline void dump_unreclaimable_slab(void)
{
}
#endif

void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);

#ifdef CONFIG_SLAB_FREELIST_RANDOM
int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
                        gfp_t gfp);
void cache_random_seq_destroy(struct kmem_cache *cachep);
#else
static inline int cache_random_seq_create(struct kmem_cache *cachep,
                                        unsigned int count, gfp_t gfp)
{
        return 0;
}
static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
#endif /* CONFIG_SLAB_FREELIST_RANDOM */

static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
{
        if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
                                &init_on_alloc)) {
                if (c->ctor)
                        return false;
                if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
                        return flags & __GFP_ZERO;
                return true;
        }
        return flags & __GFP_ZERO;
}

static inline bool slab_want_init_on_free(struct kmem_cache *c)
{
        if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
                                &init_on_free))
                return !(c->ctor ||
                         (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
        return false;
}

#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
void debugfs_slab_release(struct kmem_cache *);
#else
static inline void debugfs_slab_release(struct kmem_cache *s) { }
#endif

#ifdef CONFIG_PRINTK
#define KS_ADDRS_COUNT 16
struct kmem_obj_info {
        void *kp_ptr;
        struct slab *kp_slab;
        void *kp_objp;
        unsigned long kp_data_offset;
        struct kmem_cache *kp_slab_cache;
        void *kp_ret;
        void *kp_stack[KS_ADDRS_COUNT];
        void *kp_free_stack[KS_ADDRS_COUNT];
};
void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
#endif

void __check_heap_object(const void *ptr, unsigned long n,
                         const struct slab *slab, bool to_user);

void defer_free_barrier(void);

static inline bool slub_debug_orig_size(struct kmem_cache *s)
{
        return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
                        (s->flags & SLAB_KMALLOC));
}

#ifdef CONFIG_SLUB_DEBUG
void skip_orig_size_check(struct kmem_cache *s, const void *object);
#endif

#endif /* MM_SLAB_H */