ia64/xen-unstable

view xen/arch/ia64/linux/extable.c @ 10888:5379548bfc79

[NET] Enable TCPv4 segmentation offload in front/back drivers.
Signed-off-by: Keir Fraser <keir@xensource.com>
author kfraser@localhost.localdomain
date Tue Aug 01 11:54:45 2006 +0100 (2006-08-01)
parents 06d84bf87159
children
line source
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 */
8 #include <linux/config.h>
9 #include <linux/sort.h>
11 #include <asm/uaccess.h>
12 #include <asm/module.h>
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;
20 /* avoid overflow */
21 if (lip > rip)
22 return 1;
23 if (lip < rip)
24 return -1;
25 return 0;
26 }
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;
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 }
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 }
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;
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 }
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;
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 }