forked from Minki/linux
7567746e1c
Signed-off-by: Richard Kuo <rkuo@codeaurora.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/*
|
|
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 and
|
|
* only version 2 as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
|
* 02110-1301, USA.
|
|
*/
|
|
|
|
/*
|
|
* 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 <asm/uaccess.h>
|
|
#include <asm/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 = __copy_to_user_hexagon(dest, &empty_zero_page,
|
|
PAGE_SIZE);
|
|
if (uncleared)
|
|
return count - (PAGE_SIZE - uncleared);
|
|
count -= PAGE_SIZE;
|
|
dest += PAGE_SIZE;
|
|
}
|
|
if (count)
|
|
count = __copy_to_user_hexagon(dest, &empty_zero_page, count);
|
|
|
|
return count;
|
|
}
|
|
|
|
unsigned long clear_user_hexagon(void __user *dest, unsigned long count)
|
|
{
|
|
if (!access_ok(VERIFY_WRITE, dest, count))
|
|
return count;
|
|
else
|
|
return __clear_user_hexagon(dest, count);
|
|
}
|