/* SPDX-License-Identifier: MIT */
/* Copyright © 2025 Intel Corporation */

#ifndef __I915_PTR_UTIL_H__
#define __I915_PTR_UTIL_H__

#include <linux/types.h>

#define ptr_mask_bits(ptr, n) ({                                        \
        unsigned long __v = (unsigned long)(ptr);                       \
        (typeof(ptr))(__v & -BIT(n));                                   \
})

#define ptr_unmask_bits(ptr, n) ((unsigned long)(ptr) & (BIT(n) - 1))

#define ptr_unpack_bits(ptr, bits, n) ({                                \
        unsigned long __v = (unsigned long)(ptr);                       \
        *(bits) = __v & (BIT(n) - 1);                                   \
        (typeof(ptr))(__v & -BIT(n));                                   \
})

#define ptr_pack_bits(ptr, bits, n) ({                                  \
        unsigned long __bits = (bits);                                  \
        GEM_BUG_ON(__bits & -BIT(n));                                   \
        ((typeof(ptr))((unsigned long)(ptr) | __bits));                 \
})

#define ptr_dec(ptr) ({                                                 \
        unsigned long __v = (unsigned long)(ptr);                       \
        (typeof(ptr))(__v - 1);                                         \
})

#define ptr_inc(ptr) ({                                                 \
        unsigned long __v = (unsigned long)(ptr);                       \
        (typeof(ptr))(__v + 1);                                         \
})

#define page_mask_bits(ptr) ptr_mask_bits(ptr, PAGE_SHIFT)
#define page_unmask_bits(ptr) ptr_unmask_bits(ptr, PAGE_SHIFT)
#define page_pack_bits(ptr, bits) ptr_pack_bits(ptr, bits, PAGE_SHIFT)
#define page_unpack_bits(ptr, bits) ptr_unpack_bits(ptr, bits, PAGE_SHIFT)

static __always_inline ptrdiff_t ptrdiff(const void *a, const void *b)
{
        return a - b;
}

#define u64_to_ptr(T, x) ({                                             \
        typecheck(u64, x);                                              \
        (T *)(uintptr_t)(x);                                            \
})

/*
 * container_of_user: Extract the superclass from a pointer to a member.
 *
 * Exactly like container_of() with the exception that it plays nicely
 * with sparse for __user @ptr.
 */
#define container_of_user(ptr, type, member) ({                         \
        void __user *__mptr = (void __user *)(ptr);                     \
        BUILD_BUG_ON_MSG(!__same_type(*(ptr), typeof_member(type, member)) && \
                         !__same_type(*(ptr), void),                    \
                         "pointer type mismatch in container_of()");    \
        ((type __user *)(__mptr - offsetof(type, member))); })

#endif /* __I915_PTR_UTIL_H__ */