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 #include <linux/hardirq.h> 38 39 static inline int 40 fault_in_multipages_writeable(char __user *uaddr, int size) 41 { 42 int ret = 0; 43 char __user *end = uaddr + size - 1; 44 45 if (unlikely(size == 0)) 46 return ret; 47 48 /* 49 * Writing zeroes into userspace here is OK, because we know that if 50 * the zero gets there, we'll be overwriting it. 51 */ 52 while (uaddr <= end) { 53 ret = subyte(uaddr, 0); 54 if (ret != 0) 55 return -EFAULT; 56 uaddr += PAGE_SIZE; 57 } 58 59 /* Check whether the range spilled into the next page. */ 60 if (((unsigned long)uaddr & ~PAGE_MASK) == 61 ((unsigned long)end & ~PAGE_MASK)) 62 ret = subyte(end, 0); 63 64 return ret; 65 } 66 67 static inline int 68 fault_in_multipages_readable(const char __user *uaddr, int size) 69 { 70 char c; 71 int ret = 0; 72 const char __user *end = uaddr + size - 1; 73 74 if (unlikely(size == 0)) 75 return ret; 76 77 while (uaddr <= end) { 78 ret = -copyin(uaddr, &c, 1); 79 if (ret != 0) 80 return -EFAULT; 81 uaddr += PAGE_SIZE; 82 } 83 84 /* Check whether the range spilled into the next page. */ 85 if (((unsigned long)uaddr & ~PAGE_MASK) == 86 ((unsigned long)end & ~PAGE_MASK)) { 87 ret = -copyin(end, &c, 1); 88 } 89 90 return ret; 91 } 92 93 #endif /* _LINUX_PAGEMAP_H_ */ 94