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
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