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

/*
 * SLUB : A Slab allocator without object queues.
 *
 * (C) 2007 SGI, Christoph Lameter
 */
#include <linux/kfence.h>
#include <linux/kobject.h>
#include <linux/reciprocal_div.h>
#include <linux/local_lock.h>

enum stat_item {
    ALLOC_FASTPATH,        /* Allocation from cpu slab */
    ALLOC_SLOWPATH,        /* Allocation by getting a new cpu slab */
    FREE_FASTPATH,        /* Free to cpu slab */
    FREE_SLOWPATH,        /* Freeing not to cpu slab */
    FREE_FROZEN,        /* Freeing to frozen slab */
    FREE_ADD_PARTIAL,    /* Freeing moves slab to partial list */
    FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
    ALLOC_FROM_PARTIAL,    /* Cpu slab acquired from node partial list */
    ALLOC_SLAB,        /* Cpu slab acquired from page allocator */
    ALLOC_REFILL,        /* Refill cpu slab from slab freelist */
    ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
    FREE_SLAB,        /* Slab freed to the page allocator */
    CPUSLAB_FLUSH,        /* Abandoning of the cpu slab */
    DEACTIVATE_FULL,    /* Cpu slab was full when deactivated */
    DEACTIVATE_EMPTY,    /* Cpu slab was empty when deactivated */
    DEACTIVATE_TO_HEAD,    /* Cpu slab was moved to the head of partials */
    DEACTIVATE_TO_TAIL,    /* Cpu slab was moved to the tail of partials */
    DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
    DEACTIVATE_BYPASS,    /* Implicit deactivation */
    ORDER_FALLBACK,        /* Number of times fallback was necessary */
    CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
    CMPXCHG_DOUBLE_FAIL,    /* Number of times that cmpxchg double did not match */
    CPU_PARTIAL_ALLOC,    /* Used cpu partial on alloc */
    CPU_PARTIAL_FREE,    /* Refill cpu partial on free */
    CPU_PARTIAL_NODE,    /* Refill cpu partial from node partial */
    CPU_PARTIAL_DRAIN,    /* Drain cpu partial to node partial */
    NR_SLUB_STAT_ITEMS
};

#ifndef CONFIG_SLUB_TINY
/*
 * When changing the layout, make sure freelist and tid are still compatible
 * with this_cpu_cmpxchg_double() alignment requirements.
 */
struct kmem_cache_cpu {
    union {
        struct {
            void **freelist;    /* Pointer to next available object */
            unsigned long tid;    /* Globally unique transaction id */
        };
        freelist_aba_t freelist_tid;
    };
    struct slab *slab;    /* The slab from which we are allocating */
#ifdef CONFIG_SLUB_CPU_PARTIAL
    struct slab *partial;    /* Partially allocated slabs */
#endif
#ifdef CONFIG_SLUB_STATS
    unsigned int stat[NR_SLUB_STAT_ITEMS];
#endif
} __aligned(2 * sizeof(void *));
#endif /* CONFIG_SLUB_TINY */

#ifdef CONFIG_SLUB_CPU_PARTIAL
#define slub_percpu_partial(c)            ((c)->partial)

#define slub_set_percpu_partial(c, p)        \
({                        \
    slub_percpu_partial(c) = (p)->next;    \
})

#define slub_percpu_partial_read_once(c)    READ_ONCE(slub_percpu_partial(c))
#else
#define slub_percpu_partial(c)            NULL

#define slub_set_percpu_partial(c, p)

#define slub_percpu_partial_read_once(c)    NULL
#endif /* CONFIG_SLUB_CPU_PARTIAL */

/*
 * 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.
 */
union kmem_cache_order_objects {
    struct {
        unsigned long objects : BITS_PER_LONG / 2;
        unsigned long order : BITS_PER_LONG / 2;
    };
    unsigned long x;
};

/*
 * Slab cache management.
 */
struct kmem_cache {
#ifndef CONFIG_SLUB_TINY
    /* PaX: adjust PERCPU_AUTOSLAB_RESERVE for the __percpu fields */
    struct kmem_cache_cpu __percpu *cpu_slab;
#ifdef CONFIG_SLUB_DYNORDER
    union kmem_cache_order_objects __percpu *cpu_oo;
#endif
#endif
    local_lock_t __percpu *cpu_slab_lock;    /* Protects the fields above */
    /* Used for retrieving partial slabs, etc. */
    slab_flags_t flags;
    unsigned int min_partial;
    atomic_t min_partial_pages;
    unsigned int size;        /* Object size including metadata */
    unsigned int object_size;    /* Object size without metadata */
    struct reciprocal_value reciprocal_size;

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

    unsigned int offset;        /* Free pointer offset */
#ifdef CONFIG_SLUB_CPU_PARTIAL
    /* Number of per cpu partial objects to keep around */
    unsigned int cpu_partial;
    /* Number of per cpu partial slab pages to keep around */
    atomic_t cpu_partial_slab_pages;
#endif
    union kmem_cache_order_objects def_oo;

    /* Allocation and freeing of slabs */
    gfp_t allocflags;        /* gfp flags to use on each alloc */
    atomic_t refcount;        /* Refcount for slab cache destroy */
    void (*ctor)(void *object);    /* Object constructor */
#ifdef CONFIG_KALLSYMS
    ssize_t (*print)(char *buffer, size_t buflen, void *obj, const char *name);
#endif
    unsigned int inuse;        /* Offset to metadata */
    unsigned int align;        /* Alignment */
    unsigned int red_left_pad;    /* Left redzone padding size */
#ifdef CONFIG_GRKERNSEC_SLAB_OBJREUSE_HARDEN
    unsigned short pad_space;
#endif
    const char *name;        /* Name (only for display!) */
    struct list_head list;        /* List of slab caches */
#ifdef CONFIG_SLUB_SYSFS
    struct kobject kobj;        /* For sysfs */
#endif
#ifdef CONFIG_SLAB_FREELIST_HARDENED
    unsigned long random;
#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_PAX_AUTOSLAB_PLUGIN_AUTOTYPENAME
    unsigned int typesize;
    const char *typename;
    const struct btf_type *btftype;
#ifdef CONFIG_SLUB_DEBUG_MEMBERSHIP
    size_t nmemberships;
    struct membership {
        const struct btf_type *btftype;
        size_t offset;
    } *memberships;
#endif
#endif

    struct kmem_cache_node *node[MAX_NUMNODES];
};

#ifdef CONFIG_PAX_AUTOSLAB_PLUGIN_AUTOTYPENAME
extern struct btf *btf_vmlinux;
#endif

#ifdef CONFIG_SLUB_DEBUG_MEMBERSHIP
bool check_membership(struct kmem_cache *s, void *x);
#else
static inline bool check_membership(struct kmem_cache *s, void *x) { return true; }
#endif

#ifdef CONFIG_SLUB_SYSFS
#define SLAB_SUPPORTS_SYSFS 1
void sysfs_slab_unlink(struct kmem_cache *s);
void sysfs_slab_release(struct kmem_cache *s);
#else
static inline void sysfs_slab_unlink(struct kmem_cache *s) { }
static inline void sysfs_slab_release(struct kmem_cache *s) { }
#endif

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

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

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

static inline const void *ptr_to_obj(struct kmem_cache *s, const struct slab *slab, const void *ptr)
{
    const void *obj;

    obj = ptr - (ptr - slab_obj_address(slab)) % s->size;
    return fixup_red_left(s, (void *)obj);
}

/* Determine object index from a given position */
static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
                      const 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_obj_address(slab), obj);
}

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