// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
 */

/*
 * Support for user memory access from kernel.  This will
 * probably be inlined for performance at some point, but
 * for ease of debug, and to a lesser degree for code size,
 * we implement here as subroutines.
 */
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/pgtable.h>

/*
 * For clear_user(), exploit previously defined copy_to_user function
 * and the fact that we've got a handy zero page defined in kernel/head.S
 *
 * dczero here would be even faster.
 */
__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count)
{
        long uncleared;

        while (count > PAGE_SIZE) {
                uncleared = raw_copy_to_user(dest, &empty_zero_page, PAGE_SIZE);
                if (uncleared)
                        return count - (PAGE_SIZE - uncleared);
                count -= PAGE_SIZE;
                dest += PAGE_SIZE;
        }
        if (count)
                count = raw_copy_to_user(dest, &empty_zero_page, count);

        return count;
}