summaryrefslogtreecommitdiff
path: root/arch/hexagon/mm/uaccess.c
blob: 650bca92f0b750d0d1e734d9a19057625b881b7c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
// 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;
}

unsigned long clear_user_hexagon(void __user *dest, unsigned long count)
{
	if (!access_ok(dest, count))
		return count;
	else
		return __clear_user_hexagon(dest, count);
}