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

#include <linux/kfence.h>
#include <linux/reciprocal_div.h>

/*
 * Definitions unique to the original Linux SLAB allocator.
 */

struct kmem_cache {
    /* PaX: adjust PERCPU_AUTOSLAB_RESERVE for the __percpu fields */
    struct array_cache __percpu *cpu_cache;

/* 1) Cache tunables. Protected by slab_mutex */
    unsigned int batchcount;
    unsigned int limit;
    unsigned int shared;

    unsigned int size;
    struct reciprocal_value reciprocal_buffer_size;
#ifdef CONFIG_GRKERNSEC_SLAB_OBJREUSE_HARDEN
    unsigned short pad_space;
#endif

/* 2) touched by every alloc & free from the backend */

    slab_flags_t flags;        /* constant flags */
    unsigned int num;        /* # of objs per slab */

/* 3) cache_grow/shrink */
    /* order of pgs per slab (2^n) */
    unsigned int gfporder;

    /* force GFP flags, e.g. GFP_DMA */
    gfp_t allocflags;

    size_t colour;            /* cache colouring range */
    unsigned int colour_off;    /* colour offset */
    unsigned int freelist_size;

    /* constructor func */
    void (*ctor)(void *obj);
#ifdef CONFIG_KALLSYMS
    ssize_t (*print)(char *buffer, size_t buflen, void *obj, const char *name);
#endif

/* 4) cache creation/removal */
    const char *name;
    struct list_head list;
    atomic_t refcount;
    int object_size;
    int align;

/* 5) statistics */
#ifdef CONFIG_DEBUG_SLAB
    unsigned long num_active;
    unsigned long num_allocations;
    unsigned long high_mark;
    unsigned long grown;
    unsigned long reaped;
    unsigned long errors;
    unsigned long max_freeable;
    unsigned long node_allocs;
    unsigned long node_frees;
    unsigned long node_overflow;
    atomic_unchecked_t allochit;
    atomic_unchecked_t allocmiss;
    atomic_unchecked_t freehit;
    atomic_unchecked_t freemiss;
#ifdef CONFIG_PAX_MEMORY_SANITIZE
    atomic_unchecked_t sanitized;
    atomic_unchecked_t not_sanitized;
#endif

    /*
     * If debugging is enabled, then the allocator can add additional
     * fields and/or padding to every object. 'size' contains the total
     * object size including these internal fields, while 'obj_offset'
     * and 'object_size' contain the offset to the user object and its
     * size.
     */
    int obj_offset;
#endif /* CONFIG_DEBUG_SLAB */

#ifdef CONFIG_KASAN_GENERIC
    struct kasan_cache kasan_info;
#endif

#ifdef CONFIG_SLAB_FREELIST_RANDOM
    unsigned int *random_seq;
#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;
#endif

    struct kmem_cache_node *node[MAX_NUMNODES];
};

static inline const void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
                const void *x)
{
    const void *object = x - (x - slab->s_mem) % cache->size;
    const void *last_object = slab->s_mem + (cache->num - 1) * cache->size;

    if (unlikely(object > last_object))
        return last_object;
    else
        return object;
}

static inline void sysfs_slab_unlink(struct kmem_cache *s) { }
static inline void sysfs_slab_release(struct kmem_cache *s) { }

/*
 * We want to avoid an expensive divide : (offset / cache->size)
 *   Using the fact that size is a constant for a particular cache,
 *   we can replace (offset / cache->size) by
 *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
 */
static inline unsigned int obj_to_index(const struct kmem_cache *cache,
                    const struct slab *slab, const void *obj)
{
    u32 offset = (obj - slab->s_mem);
    return reciprocal_divide(offset, cache->reciprocal_buffer_size);
}

static inline void *index_to_obj(struct kmem_cache *cache,
                 const struct slab *slab, unsigned int idx)
{
    return slab->s_mem + cache->size * idx;
}

#ifdef CONFIG_DEBUG_SLAB
static int obj_offset(struct kmem_cache *cachep)
{
    return cachep->obj_offset;
}
#else
#define obj_offset(x)            0
#endif

static inline const void *ptr_to_obj(struct kmem_cache *cachep, const struct slab *slab, const void *ptr)
{
    unsigned int objnr;

    if (ptr < slab->s_mem)
        return NULL;
    objnr = obj_to_index(cachep, slab, ptr);
    if (objnr >= cachep->num)
        return NULL;

    return index_to_obj(cachep, slab, objnr) + obj_offset(cachep);
}

void print_objinfo(struct kmem_cache *cachep, void *objp, int lines);

static inline int objs_per_slab(const struct kmem_cache *cache,
                     const struct slab *slab)
{
    if (is_kfence_address(slab_page_address(slab)))
        return 1;
    return cache->num;
}

#endif    /* _LINUX_SLAB_DEF_H */