Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/lib/extable.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 2120 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * lib/extable.c |
3 | * Derived from arch/ppc/mm/extable.c and arch/i386/mm/extable.c. |
4 | * |
5 | * Copyright (C) 2004 Paul Mackerras, IBM Corp. |
6 | * |
7 | * This program is free software; you can redistribute it and/or |
8 | * modify it under the terms of the GNU General Public License |
9 | * as published by the Free Software Foundation; either version |
10 | * 2 of the License, or (at your option) any later version. |
11 | */ |
12 | |
13 | #include <linux/config.h> |
14 | #include <linux/module.h> |
15 | #include <linux/init.h> |
16 | #include <linux/sort.h> |
17 | #include <asm/uaccess.h> |
18 | |
19 | extern struct exception_table_entry __start___ex_table[]; |
20 | extern struct exception_table_entry __stop___ex_table[]; |
21 | |
22 | #ifndef ARCH_HAS_SORT_EXTABLE |
23 | /* |
24 | * The exception table needs to be sorted so that the binary |
25 | * search that we use to find entries in it works properly. |
26 | * This is used both for the kernel exception table and for |
27 | * the exception tables of modules that get loaded. |
28 | */ |
29 | static int cmp_ex(const void *a, const void *b) |
30 | { |
31 | const struct exception_table_entry *x = a, *y = b; |
32 | |
33 | /* avoid overflow */ |
34 | if (x->insn > y->insn) |
35 | return 1; |
36 | if (x->insn < y->insn) |
37 | return -1; |
38 | return 0; |
39 | } |
40 | |
41 | void sort_extable(struct exception_table_entry *start, |
42 | struct exception_table_entry *finish) |
43 | { |
44 | sort(start, finish - start, sizeof(struct exception_table_entry), |
45 | cmp_ex, NULL); |
46 | } |
47 | #endif |
48 | |
49 | #ifndef ARCH_HAS_SEARCH_EXTABLE |
50 | /* |
51 | * Search one exception table for an entry corresponding to the |
52 | * given instruction address, and return the address of the entry, |
53 | * or NULL if none is found. |
54 | * We use a binary search, and thus we assume that the table is |
55 | * already sorted. |
56 | */ |
57 | const struct exception_table_entry * |
58 | search_extable(const struct exception_table_entry *first, |
59 | const struct exception_table_entry *last, |
60 | unsigned long value) |
61 | { |
62 | while (first <= last) { |
63 | const struct exception_table_entry *mid; |
64 | |
65 | mid = (last - first) / 2 + first; |
66 | /* |
67 | * careful, the distance between entries can be |
68 | * larger than 2GB: |
69 | */ |
70 | if (mid->insn < value) |
71 | first = mid + 1; |
72 | else if (mid->insn > value) |
73 | last = mid - 1; |
74 | else |
75 | return mid; |
76 | } |
77 | return NULL; |
78 | } |
79 | #endif |