46 lines
1.1 KiB
C
46 lines
1.1 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
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*/
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/*
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* Support for user memory access from kernel. This will
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* probably be inlined for performance at some point, but
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* for ease of debug, and to a lesser degree for code size,
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* we implement here as subroutines.
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*/
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/pgtable.h>
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/*
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* For clear_user(), exploit previously defined copy_to_user function
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* and the fact that we've got a handy zero page defined in kernel/head.S
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*
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* dczero here would be even faster.
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*/
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__kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count)
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{
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long uncleared;
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while (count > PAGE_SIZE) {
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uncleared = raw_copy_to_user(dest, &empty_zero_page, PAGE_SIZE);
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if (uncleared)
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return count - (PAGE_SIZE - uncleared);
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count -= PAGE_SIZE;
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dest += PAGE_SIZE;
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}
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if (count)
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count = raw_copy_to_user(dest, &empty_zero_page, count);
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return count;
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}
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unsigned long clear_user_hexagon(void __user *dest, unsigned long count)
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{
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if (!access_ok(dest, count))
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return count;
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else
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return __clear_user_hexagon(dest, count);
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}
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