Kconfig: HSO driver bugfixes and updates
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / arch / sparc64 / lib / user_fixup.c
blob19d1fdb17d0e8b4f5b3ac6ce0a72fe7c11c65a6b
1 /* user_fixup.c: Fix up user copy faults.
3 * Copyright (C) 2004 David S. Miller <davem@redhat.com>
4 */
6 #include <linux/compiler.h>
7 #include <linux/kernel.h>
8 #include <linux/string.h>
9 #include <linux/errno.h>
10 #include <asm/uaccess.h>
12 /* Calculating the exact fault address when using
13 * block loads and stores can be very complicated.
15 * Instead of trying to be clever and handling all
16 * of the cases, just fix things up simply here.
19 static unsigned long compute_size(unsigned long start, unsigned long size, unsigned long *offset)
21 unsigned long fault_addr = current_thread_info()->fault_address;
22 unsigned long end = start + size;
24 if (fault_addr < start || fault_addr >= end) {
25 *offset = 0;
26 } else {
27 *offset = start - fault_addr;
28 size = end - fault_addr;
30 return size;
33 unsigned long copy_from_user_fixup(void *to, const void __user *from, unsigned long size)
35 unsigned long offset;
37 size = compute_size((unsigned long) from, size, &offset);
38 if (likely(size))
39 memset(to + offset, 0, size);
41 return size;
44 unsigned long copy_to_user_fixup(void __user *to, const void *from, unsigned long size)
46 unsigned long offset;
48 return compute_size((unsigned long) to, size, &offset);
51 unsigned long copy_in_user_fixup(void __user *to, void __user *from, unsigned long size)
53 unsigned long fault_addr = current_thread_info()->fault_address;
54 unsigned long start = (unsigned long) to;
55 unsigned long end = start + size;
57 if (fault_addr >= start && fault_addr < end)
58 return end - fault_addr;
60 start = (unsigned long) from;
61 end = start + size;
62 if (fault_addr >= start && fault_addr < end)
63 return end - fault_addr;
65 return size;