1 /* 2 * Copyright (c) 2015 François Tigeot 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #ifndef _LINUX_PAGEMAP_H_ 28 #define _LINUX_PAGEMAP_H_ 29 30 #include <linux/mm.h> 31 #include <linux/list.h> 32 #include <linux/highmem.h> 33 #include <linux/compiler.h> 34 #include <asm/uaccess.h> 35 #include <linux/gfp.h> 36 #include <linux/bitops.h> 37 38 static inline int 39 fault_in_multipages_writeable(char __user *uaddr, int size) 40 { 41 int ret = 0; 42 char __user *end = uaddr + size - 1; 43 44 if (unlikely(size == 0)) 45 return ret; 46 47 /* 48 * Writing zeroes into userspace here is OK, because we know that if 49 * the zero gets there, we'll be overwriting it. 50 */ 51 while (uaddr <= end) { 52 ret = subyte(uaddr, 0); 53 if (ret != 0) 54 return -EFAULT; 55 uaddr += PAGE_SIZE; 56 } 57 58 /* Check whether the range spilled into the next page. */ 59 if (((unsigned long)uaddr & ~PAGE_MASK) == 60 ((unsigned long)end & ~PAGE_MASK)) 61 ret = subyte(end, 0); 62 63 return ret; 64 } 65 66 static inline int 67 fault_in_multipages_readable(const char __user *uaddr, int size) 68 { 69 char c; 70 int ret = 0; 71 const char __user *end = uaddr + size - 1; 72 73 if (unlikely(size == 0)) 74 return ret; 75 76 while (uaddr <= end) { 77 ret = -copyin(uaddr, &c, 1); 78 if (ret != 0) 79 return -EFAULT; 80 uaddr += PAGE_SIZE; 81 } 82 83 /* Check whether the range spilled into the next page. */ 84 if (((unsigned long)uaddr & ~PAGE_MASK) == 85 ((unsigned long)end & ~PAGE_MASK)) { 86 ret = -copyin(end, &c, 1); 87 } 88 89 return ret; 90 } 91 92 #endif /* _LINUX_PAGEMAP_H_ */ 93