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- // 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);
- }
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