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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> | |
11 | #include <asm/module.h> | |
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 | ||
56 | const struct exception_table_entry * | |
57 | search_extable (const struct exception_table_entry *first, | |
58 | const struct exception_table_entry *last, | |
59 | unsigned long ip) | |
60 | { | |
61 | const struct exception_table_entry *mid; | |
62 | unsigned long mid_ip; | |
63 | long diff; | |
64 | ||
65 | while (first <= last) { | |
66 | mid = &first[(last - first)/2]; | |
67 | mid_ip = (u64) &mid->addr + mid->addr; | |
68 | diff = mid_ip - ip; | |
69 | if (diff == 0) | |
70 | return mid; | |
71 | else if (diff < 0) | |
72 | first = mid + 1; | |
73 | else | |
74 | last = mid - 1; | |
75 | } | |
76 | return NULL; | |
77 | } | |
78 | ||
79 | void | |
80 | ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e) | |
81 | { | |
82 | long fix = (u64) &e->cont + e->cont; | |
83 | ||
84 | regs->r8 = -EFAULT; | |
85 | if (fix & 4) | |
86 | regs->r9 = 0; | |
87 | regs->cr_iip = fix & ~0xf; | |
88 | ia64_psr(regs)->ri = fix & 0x3; /* set continuation slot number */ | |
89 | } |