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1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Derived from arch/ppc/mm/extable.c and arch/i386/mm/extable.c. |
3 | * | |
4 | * Copyright (C) 2004 Paul Mackerras, IBM Corp. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/config.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/sort.h> | |
16 | #include <asm/uaccess.h> | |
17 | ||
1da177e4 LT |
18 | #ifndef ARCH_HAS_SORT_EXTABLE |
19 | /* | |
20 | * The exception table needs to be sorted so that the binary | |
21 | * search that we use to find entries in it works properly. | |
22 | * This is used both for the kernel exception table and for | |
23 | * the exception tables of modules that get loaded. | |
24 | */ | |
25 | static int cmp_ex(const void *a, const void *b) | |
26 | { | |
27 | const struct exception_table_entry *x = a, *y = b; | |
28 | ||
29 | /* avoid overflow */ | |
30 | if (x->insn > y->insn) | |
31 | return 1; | |
32 | if (x->insn < y->insn) | |
33 | return -1; | |
34 | return 0; | |
35 | } | |
36 | ||
37 | void sort_extable(struct exception_table_entry *start, | |
38 | struct exception_table_entry *finish) | |
39 | { | |
40 | sort(start, finish - start, sizeof(struct exception_table_entry), | |
41 | cmp_ex, NULL); | |
42 | } | |
43 | #endif | |
44 | ||
45 | #ifndef ARCH_HAS_SEARCH_EXTABLE | |
46 | /* | |
47 | * Search one exception table for an entry corresponding to the | |
48 | * given instruction address, and return the address of the entry, | |
49 | * or NULL if none is found. | |
50 | * We use a binary search, and thus we assume that the table is | |
51 | * already sorted. | |
52 | */ | |
53 | const struct exception_table_entry * | |
54 | search_extable(const struct exception_table_entry *first, | |
55 | const struct exception_table_entry *last, | |
56 | unsigned long value) | |
57 | { | |
58 | while (first <= last) { | |
59 | const struct exception_table_entry *mid; | |
60 | ||
61 | mid = (last - first) / 2 + first; | |
62 | /* | |
63 | * careful, the distance between entries can be | |
64 | * larger than 2GB: | |
65 | */ | |
66 | if (mid->insn < value) | |
67 | first = mid + 1; | |
68 | else if (mid->insn > value) | |
69 | last = mid - 1; | |
70 | else | |
71 | return mid; | |
72 | } | |
73 | return NULL; | |
74 | } | |
75 | #endif |