Merge branch 'for-2.6.30' into for-2.6.31
[linux-2.6] / arch / x86 / mm / extable.c
1 #include <linux/module.h>
2 #include <linux/spinlock.h>
3 #include <asm/uaccess.h>
4
5
6 int fixup_exception(struct pt_regs *regs)
7 {
8         const struct exception_table_entry *fixup;
9
10 #ifdef CONFIG_PNPBIOS
11         if (unlikely(SEGMENT_IS_PNP_CODE(regs->cs))) {
12                 extern u32 pnp_bios_fault_eip, pnp_bios_fault_esp;
13                 extern u32 pnp_bios_is_utter_crap;
14                 pnp_bios_is_utter_crap = 1;
15                 printk(KERN_CRIT "PNPBIOS fault.. attempting recovery.\n");
16                 __asm__ volatile(
17                         "movl %0, %%esp\n\t"
18                         "jmp *%1\n\t"
19                         : : "g" (pnp_bios_fault_esp), "g" (pnp_bios_fault_eip));
20                 panic("do_trap: can't hit this");
21         }
22 #endif
23
24         fixup = search_exception_tables(regs->ip);
25         if (fixup) {
26                 /* If fixup is less than 16, it means uaccess error */
27                 if (fixup->fixup < 16) {
28                         current_thread_info()->uaccess_err = -EFAULT;
29                         regs->ip += fixup->fixup;
30                         return 1;
31                 }
32                 regs->ip = fixup->fixup;
33                 return 1;
34         }
35
36         return 0;
37 }
38
39 #ifdef CONFIG_X86_64
40 /*
41  * Need to defined our own search_extable on X86_64 to work around
42  * a B stepping K8 bug.
43  */
44 const struct exception_table_entry *
45 search_extable(const struct exception_table_entry *first,
46                const struct exception_table_entry *last,
47                unsigned long value)
48 {
49         /* B stepping K8 bug */
50         if ((value >> 32) == 0)
51                 value |= 0xffffffffUL << 32;
52
53         while (first <= last) {
54                 const struct exception_table_entry *mid;
55                 long diff;
56
57                 mid = (last - first) / 2 + first;
58                 diff = mid->insn - value;
59                 if (diff == 0)
60                         return mid;
61                 else if (diff < 0)
62                         first = mid+1;
63                 else
64                         last = mid-1;
65         }
66         return NULL;
67 }
68 #endif