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1da177e4 LT |
1 | /* |
2 | * Kernel exception handling table support. Derived from arch/alpha/mm/extable.c. | |
3 | * | |
4 | * Copyright (C) 1998, 1999, 2001-2002, 2004 Hewlett-Packard Co | |
5 | * David Mosberger-Tang <davidm@hpl.hp.com> | |
6 | */ | |
7 | ||
1da177e4 LT |
8 | #include <linux/sort.h> |
9 | ||
10 | #include <asm/uaccess.h> | |
1dcd775e | 11 | #include <linux/module.h> |
1da177e4 LT |
12 | |
13 | static int cmp_ex(const void *a, const void *b) | |
14 | { | |
15 | const struct exception_table_entry *l = a, *r = b; | |
16 | u64 lip = (u64) &l->addr + l->addr; | |
17 | u64 rip = (u64) &r->addr + r->addr; | |
18 | ||
19 | /* avoid overflow */ | |
20 | if (lip > rip) | |
21 | return 1; | |
22 | if (lip < rip) | |
23 | return -1; | |
24 | return 0; | |
25 | } | |
26 | ||
27 | static void swap_ex(void *a, void *b, int size) | |
28 | { | |
29 | struct exception_table_entry *l = a, *r = b, tmp; | |
30 | u64 delta = (u64) r - (u64) l; | |
31 | ||
32 | tmp = *l; | |
33 | l->addr = r->addr + delta; | |
34 | l->cont = r->cont + delta; | |
35 | r->addr = tmp.addr - delta; | |
36 | r->cont = tmp.cont - delta; | |
37 | } | |
38 | ||
39 | /* | |
40 | * Sort the exception table. It's usually already sorted, but there | |
41 | * may be unordered entries due to multiple text sections (such as the | |
42 | * .init text section). Note that the exception-table-entries contain | |
43 | * location-relative addresses, which requires a bit of care during | |
44 | * sorting to avoid overflows in the offset members (e.g., it would | |
45 | * not be safe to make a temporary copy of an exception-table entry on | |
46 | * the stack, because the stack may be more than 2GB away from the | |
47 | * exception-table). | |
48 | */ | |
49 | void sort_extable (struct exception_table_entry *start, | |
50 | struct exception_table_entry *finish) | |
51 | { | |
52 | sort(start, finish - start, sizeof(struct exception_table_entry), | |
53 | cmp_ex, swap_ex); | |
54 | } | |
55 | ||
ad6561df RR |
56 | static inline unsigned long ex_to_addr(const struct exception_table_entry *x) |
57 | { | |
1dcd775e | 58 | return (unsigned long)&x->addr + x->addr; |
ad6561df RR |
59 | } |
60 | ||
61 | #ifdef CONFIG_MODULES | |
62 | /* | |
63 | * Any entry referring to the module init will be at the beginning or | |
64 | * the end. | |
65 | */ | |
66 | void trim_init_extable(struct module *m) | |
67 | { | |
68 | /*trim the beginning*/ | |
69 | while (m->num_exentries && | |
70 | within_module_init(ex_to_addr(&m->extable[0]), m)) { | |
71 | m->extable++; | |
72 | m->num_exentries--; | |
73 | } | |
74 | /*trim the end*/ | |
75 | while (m->num_exentries && | |
76 | within_module_init(ex_to_addr(&m->extable[m->num_exentries-1]), | |
77 | m)) | |
78 | m->num_exentries--; | |
79 | } | |
80 | #endif /* CONFIG_MODULES */ | |
81 | ||
1da177e4 LT |
82 | const struct exception_table_entry * |
83 | search_extable (const struct exception_table_entry *first, | |
84 | const struct exception_table_entry *last, | |
85 | unsigned long ip) | |
86 | { | |
87 | const struct exception_table_entry *mid; | |
88 | unsigned long mid_ip; | |
89 | long diff; | |
90 | ||
91 | while (first <= last) { | |
92 | mid = &first[(last - first)/2]; | |
93 | mid_ip = (u64) &mid->addr + mid->addr; | |
94 | diff = mid_ip - ip; | |
95 | if (diff == 0) | |
96 | return mid; | |
97 | else if (diff < 0) | |
98 | first = mid + 1; | |
99 | else | |
100 | last = mid - 1; | |
101 | } | |
102 | return NULL; | |
103 | } | |
104 | ||
105 | void | |
106 | ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e) | |
107 | { | |
108 | long fix = (u64) &e->cont + e->cont; | |
109 | ||
110 | regs->r8 = -EFAULT; | |
111 | if (fix & 4) | |
112 | regs->r9 = 0; | |
113 | regs->cr_iip = fix & ~0xf; | |
114 | ia64_psr(regs)->ri = fix & 0x3; /* set continuation slot number */ | |
115 | } |