1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
4 */
5
6/*
7 * Support for user memory access from kernel.  This will
8 * probably be inlined for performance at some point, but
9 * for ease of debug, and to a lesser degree for code size,
10 * we implement here as subroutines.
11 */
12#include <linux/types.h>
13#include <linux/uaccess.h>
14#include <linux/pgtable.h>
15
16/*
17 * For clear_user(), exploit previously defined copy_to_user function
18 * and the fact that we've got a handy zero page defined in kernel/head.S
19 *
20 * dczero here would be even faster.
21 */
22__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count)
23{
24	long uncleared;
25
26	while (count > PAGE_SIZE) {
27		uncleared = raw_copy_to_user(dest, &empty_zero_page, PAGE_SIZE);
28		if (uncleared)
29			return count - (PAGE_SIZE - uncleared);
30		count -= PAGE_SIZE;
31		dest += PAGE_SIZE;
32	}
33	if (count)
34		count = raw_copy_to_user(dest, &empty_zero_page, count);
35
36	return count;
37}
38