1 /*
2 * linux/arch/alpha/mm/extable.c
3 */
4
5 #include <linux/config.h>
6 #include <linux/module.h>
7 #include <asm/uaccess.h>
8
9 extern const struct exception_table_entry __start___ex_table[];
10 extern const struct exception_table_entry __stop___ex_table[];
11
12 static inline unsigned
search_one_table(const struct exception_table_entry * first,const struct exception_table_entry * last,signed long value)13 search_one_table(const struct exception_table_entry *first,
14 const struct exception_table_entry *last,
15 signed long value)
16 {
17 /* Abort early if the search value is out of range. */
18 if (value != (signed int)value)
19 return 0;
20
21 while (first <= last) {
22 const struct exception_table_entry *mid;
23 long diff;
24
25 mid = (last - first) / 2 + first;
26 diff = mid->insn - value;
27 if (diff == 0)
28 return mid->fixup.unit;
29 else if (diff < 0)
30 first = mid+1;
31 else
32 last = mid-1;
33 }
34 return 0;
35 }
36
37 register unsigned long gp __asm__("$29");
38
39 static unsigned
search_exception_table_without_gp(unsigned long addr)40 search_exception_table_without_gp(unsigned long addr)
41 {
42 unsigned ret;
43
44 #ifndef CONFIG_MODULES
45 /* There is only the kernel to search. */
46 ret = search_one_table(__start___ex_table, __stop___ex_table - 1,
47 addr - gp);
48 #else
49 extern spinlock_t modlist_lock;
50 unsigned long flags;
51 /* The kernel is the last "module" -- no need to treat it special. */
52 struct module *mp;
53
54 ret = 0;
55 spin_lock_irqsave(&modlist_lock, flags);
56 for (mp = module_list; mp ; mp = mp->next) {
57 if (!mp->ex_table_start || !(mp->flags&(MOD_RUNNING|MOD_INITIALIZING)))
58 continue;
59 ret = search_one_table(mp->ex_table_start,
60 mp->ex_table_end - 1, addr - mp->gp);
61 if (ret)
62 break;
63 }
64 spin_unlock_irqrestore(&modlist_lock, flags);
65 #endif
66
67 return ret;
68 }
69
70 unsigned
search_exception_table(unsigned long addr,unsigned long exc_gp)71 search_exception_table(unsigned long addr, unsigned long exc_gp)
72 {
73 unsigned ret;
74
75 #ifndef CONFIG_MODULES
76 ret = search_one_table(__start___ex_table, __stop___ex_table - 1,
77 addr - exc_gp);
78 if (ret) return ret;
79 #else
80 extern spinlock_t modlist_lock;
81 unsigned long flags;
82 /* The kernel is the last "module" -- no need to treat it special. */
83 struct module *mp;
84
85 ret = 0;
86 spin_lock_irqsave(&modlist_lock, flags);
87 for (mp = module_list; mp ; mp = mp->next) {
88 if (!mp->ex_table_start || !(mp->flags&(MOD_RUNNING|MOD_INITIALIZING)))
89 continue;
90 ret = search_one_table(mp->ex_table_start,
91 mp->ex_table_end - 1, addr - exc_gp);
92 if (ret)
93 break;
94 }
95 spin_unlock_irqrestore(&modlist_lock, flags);
96 if (ret) return ret;
97 #endif
98
99 /*
100 * The search failed with the exception gp. To be safe, try the
101 * old method before giving up.
102 */
103 ret = search_exception_table_without_gp(addr);
104 if (ret) {
105 printk(KERN_ALERT "%s: [%lx] EX_TABLE search fail with"
106 "exc frame GP, success with raw GP\n",
107 current->comm, addr);
108 return ret;
109 }
110
111 return 0;
112 }
113