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

#include <linux/compiler.h>

extern void *__user_addr_min, *__user_addr_max;

#define put_user(x, ptr)                                        \
({                                                              \
        typeof(ptr) __pu_ptr = (ptr);                           \
        __chk_user_ptr(__pu_ptr);                               \
        WRITE_ONCE(*(__pu_ptr), x);                             \
        0;                                                      \
})

#define get_user(x, ptr)                                        \
({                                                              \
        typeof(ptr) __pu_ptr = (ptr);                           \
        __chk_user_ptr(__pu_ptr);                               \
        x = READ_ONCE(*(__pu_ptr));                             \
        0;                                                      \
})

static void volatile_memcpy(volatile char *to, const volatile char *from, 
                            unsigned long n)
{
        while (n--)
                *(to++) = *(from++);
}

static inline int copy_from_user(void *to, const void __user volatile *from,
                                 unsigned long n)
{
        volatile_memcpy(to, from, n);
        return 0;
}

static inline int copy_to_user(void __user volatile *to, const void *from,
                               unsigned long n)
{
        volatile_memcpy(to, from, n);
        return 0;
}
#endif /* UACCESS_H */