Commit | Line | Data |
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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 | ||
8 | #include <linux/config.h> | |
9 | #include <linux/sort.h> | |
10 | ||
11 | #include <asm/uaccess.h> | |
12 | #include <asm/module.h> | |
13 | ||
14 | static int cmp_ex(const void *a, const void *b) | |
15 | { | |
16 | const struct exception_table_entry *l = a, *r = b; | |
17 | u64 lip = (u64) &l->addr + l->addr; | |
18 | u64 rip = (u64) &r->addr + r->addr; | |
19 | ||
20 | /* avoid overflow */ | |
21 | if (lip > rip) | |
22 | return 1; | |
23 | if (lip < rip) | |
24 | return -1; | |
25 | return 0; | |
26 | } | |
27 | ||
28 | static void swap_ex(void *a, void *b, int size) | |
29 | { | |
30 | struct exception_table_entry *l = a, *r = b, tmp; | |
31 | u64 delta = (u64) r - (u64) l; | |
32 | ||
33 | tmp = *l; | |
34 | l->addr = r->addr + delta; | |
35 | l->cont = r->cont + delta; | |
36 | r->addr = tmp.addr - delta; | |
37 | r->cont = tmp.cont - delta; | |
38 | } | |
39 | ||
40 | /* | |
41 | * Sort the exception table. It's usually already sorted, but there | |
42 | * may be unordered entries due to multiple text sections (such as the | |
43 | * .init text section). Note that the exception-table-entries contain | |
44 | * location-relative addresses, which requires a bit of care during | |
45 | * sorting to avoid overflows in the offset members (e.g., it would | |
46 | * not be safe to make a temporary copy of an exception-table entry on | |
47 | * the stack, because the stack may be more than 2GB away from the | |
48 | * exception-table). | |
49 | */ | |
50 | void sort_extable (struct exception_table_entry *start, | |
51 | struct exception_table_entry *finish) | |
52 | { | |
53 | sort(start, finish - start, sizeof(struct exception_table_entry), | |
54 | cmp_ex, swap_ex); | |
55 | } | |
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 ip) | |
61 | { | |
62 | const struct exception_table_entry *mid; | |
63 | unsigned long mid_ip; | |
64 | long diff; | |
65 | ||
66 | while (first <= last) { | |
67 | mid = &first[(last - first)/2]; | |
68 | mid_ip = (u64) &mid->addr + mid->addr; | |
69 | diff = mid_ip - ip; | |
70 | if (diff == 0) | |
71 | return mid; | |
72 | else if (diff < 0) | |
73 | first = mid + 1; | |
74 | else | |
75 | last = mid - 1; | |
76 | } | |
77 | return NULL; | |
78 | } | |
79 | ||
80 | void | |
81 | ia64_handle_exception (struct pt_regs *regs, const struct exception_table_entry *e) | |
82 | { | |
83 | long fix = (u64) &e->cont + e->cont; | |
84 | ||
85 | regs->r8 = -EFAULT; | |
86 | if (fix & 4) | |
87 | regs->r9 = 0; | |
88 | regs->cr_iip = fix & ~0xf; | |
89 | ia64_psr(regs)->ri = fix & 0x3; /* set continuation slot number */ | |
90 | } |