/* * Copyright (c) 2010-2011, The Linux Foundation. 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 <linux/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 = 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(VERIFY_WRITE, dest, count)) return count; else return __clear_user_hexagon(dest, count); }