From 7567746e1c0d66ac0ef8a9d8816ca694462c7370 Mon Sep 17 00:00:00 2001 From: Richard Kuo Date: Mon, 31 Oct 2011 18:48:07 -0500 Subject: Hexagon: Add user access functions Signed-off-by: Richard Kuo Acked-by: Arnd Bergmann Signed-off-by: Linus Torvalds --- arch/hexagon/mm/uaccess.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) create mode 100644 arch/hexagon/mm/uaccess.c (limited to 'arch/hexagon/mm/uaccess.c') diff --git a/arch/hexagon/mm/uaccess.c b/arch/hexagon/mm/uaccess.c new file mode 100644 index 000000000000..e748108b47a7 --- /dev/null +++ b/arch/hexagon/mm/uaccess.c @@ -0,0 +1,59 @@ +/* + * 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 +#include +#include + +/* + * 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); +} -- cgit v1.2.1