]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * This file is subject to the terms and conditions of the GNU General Public | |
3 | * License. See the file "COPYING" in the main directory of this archive | |
4 | * for more details. | |
5 | * | |
6 | * arch/sh64/mm/extable.c | |
7 | * | |
8 | * Copyright (C) 2003 Richard Curnow | |
9 | * Copyright (C) 2003, 2004 Paul Mundt | |
10 | * | |
11 | * Cloned from the 2.5 SH version.. | |
12 | */ | |
1da177e4 LT |
13 | #include <linux/rwsem.h> |
14 | #include <linux/module.h> | |
15 | #include <asm/uaccess.h> | |
16 | ||
17 | extern unsigned long copy_user_memcpy, copy_user_memcpy_end; | |
18 | extern void __copy_user_fixup(void); | |
19 | ||
20 | static const struct exception_table_entry __copy_user_fixup_ex = { | |
21 | .fixup = (unsigned long)&__copy_user_fixup, | |
22 | }; | |
23 | ||
24 | /* Some functions that may trap due to a bad user-mode address have too many loads | |
25 | and stores in them to make it at all practical to label each one and put them all in | |
26 | the main exception table. | |
27 | ||
28 | In particular, the fast memcpy routine is like this. It's fix-up is just to fall back | |
29 | to a slow byte-at-a-time copy, which is handled the conventional way. So it's functionally | |
30 | OK to just handle any trap occurring in the fast memcpy with that fixup. */ | |
31 | static const struct exception_table_entry *check_exception_ranges(unsigned long addr) | |
32 | { | |
33 | if ((addr >= (unsigned long)©_user_memcpy) && | |
34 | (addr <= (unsigned long)©_user_memcpy_end)) | |
35 | return &__copy_user_fixup_ex; | |
36 | ||
37 | return NULL; | |
38 | } | |
39 | ||
40 | /* Simple binary search */ | |
41 | const struct exception_table_entry * | |
42 | search_extable(const struct exception_table_entry *first, | |
43 | const struct exception_table_entry *last, | |
44 | unsigned long value) | |
45 | { | |
46 | const struct exception_table_entry *mid; | |
47 | ||
48 | mid = check_exception_ranges(value); | |
49 | if (mid) | |
50 | return mid; | |
51 | ||
52 | while (first <= last) { | |
53 | long diff; | |
54 | ||
55 | mid = (last - first) / 2 + first; | |
56 | diff = mid->insn - value; | |
57 | if (diff == 0) | |
58 | return mid; | |
59 | else if (diff < 0) | |
60 | first = mid+1; | |
61 | else | |
62 | last = mid-1; | |
63 | } | |
64 | ||
65 | return NULL; | |
66 | } | |
67 | ||
68 | int fixup_exception(struct pt_regs *regs) | |
69 | { | |
70 | const struct exception_table_entry *fixup; | |
71 | ||
72 | fixup = search_exception_tables(regs->pc); | |
73 | if (fixup) { | |
74 | regs->pc = fixup->fixup; | |
75 | return 1; | |
76 | } | |
77 | ||
78 | return 0; | |
79 | } | |
80 |