1 /*
2 * linux/arch/ppc64/mm/extable.c
3 *
4 * from linux/arch/i386/mm/extable.c
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/spinlock.h>
15 #include <asm/uaccess.h>
16
17 extern struct exception_table_entry __start___ex_table[];
18 extern struct exception_table_entry __stop___ex_table[];
19
20 /*
21 * The exception table needs to be sorted because we use the macros
22 * which put things into the exception table in a variety of segments
23 * as well as the init segment and the main kernel text segment.
24 */
25 static inline void
sort_ex_table(struct exception_table_entry * start,struct exception_table_entry * finish)26 sort_ex_table(struct exception_table_entry *start,
27 struct exception_table_entry *finish)
28 {
29 struct exception_table_entry el, *p, *q;
30
31 /* insertion sort */
32 for (p = start + 1; p < finish; ++p) {
33 /* start .. p-1 is sorted */
34 if (p[0].insn < p[-1].insn) {
35 /* move element p down to its right place */
36 el = *p;
37 q = p;
38 do {
39 /* el comes before q[-1], move q[-1] up one */
40 q[0] = q[-1];
41 --q;
42 } while (q > start && el.insn < q[-1].insn);
43 *q = el;
44 }
45 }
46 }
47
48 void
sort_exception_table(void)49 sort_exception_table(void)
50 {
51 sort_ex_table(__start___ex_table, __stop___ex_table);
52 }
53
54 static inline unsigned long
search_one_table(const struct exception_table_entry * first,const struct exception_table_entry * last,unsigned long value)55 search_one_table(const struct exception_table_entry *first,
56 const struct exception_table_entry *last,
57 unsigned long value)
58 {
59 while (first <= last) {
60 const struct exception_table_entry *mid;
61 long diff;
62
63 mid = (last - first) / 2 + first;
64 diff = mid->insn - value;
65 if (diff == 0)
66 return mid->fixup;
67 else if (diff < 0)
68 first = mid+1;
69 else
70 last = mid-1;
71 }
72 return 0;
73 }
74
75 extern spinlock_t modlist_lock;
76
77 unsigned long
search_exception_table(unsigned long addr)78 search_exception_table(unsigned long addr)
79 {
80 unsigned long ret = 0;
81
82 #ifndef CONFIG_MODULES
83 /* There is only the kernel to search. */
84 ret = search_one_table(__start___ex_table, __stop___ex_table-1, addr);
85 return ret;
86 #else
87 unsigned long flags;
88 /* The kernel is the last "module" -- no need to treat it special. */
89 struct module *mp;
90
91 spin_lock_irqsave(&modlist_lock, flags);
92 for (mp = module_list; mp != NULL; mp = mp->next) {
93 if (mp->ex_table_start == NULL || !(mp->flags&(MOD_RUNNING|MOD_INITIALIZING)))
94 continue;
95 ret = search_one_table(mp->ex_table_start,
96 mp->ex_table_end - 1, addr);
97 if (ret)
98 break;
99 }
100 spin_unlock_irqrestore(&modlist_lock, flags);
101 return ret;
102 #endif
103 }
104