File: /usr/src/linux/arch/ia64/mm/extable.c

1     /*
2      * Kernel exception handling table support.  Derived from arch/alpha/mm/extable.c.
3      *
4      * Copyright (C) 1998, 1999, 2001 Hewlett-Packard Co
5      * Copyright (C) 1998, 1999, 2001 David Mosberger-Tang <davidm@hpl.hp.com>
6      */
7     
8     #include <linux/config.h>
9     
10     #include <asm/uaccess.h>
11     #include <asm/module.h>
12     
13     extern const struct exception_table_entry __start___ex_table[];
14     extern const struct exception_table_entry __stop___ex_table[];
15     
16     static inline const struct exception_table_entry *
17     search_one_table (const struct exception_table_entry *first,
18     		  const struct exception_table_entry *last,
19     		  unsigned long ip, unsigned long gp)
20     {
21             while (first <= last) {
22     		const struct exception_table_entry *mid;
23     		long diff;
24     
25     		mid = &first[(last - first)/2];
26     		diff = (mid->addr + gp) - ip;
27                     if (diff == 0)
28                             return mid;
29                     else if (diff < 0)
30                             first = mid + 1;
31                     else
32                             last = mid - 1;
33             }
34             return 0;
35     }
36     
37     #ifndef CONFIG_MODULES
38     register unsigned long main_gp __asm__("gp");
39     #endif
40     
41     struct exception_fixup
42     search_exception_table (unsigned long addr)
43     {
44     	const struct exception_table_entry *entry;
45     	struct exception_fixup fix = { 0 };
46     
47     #ifndef CONFIG_MODULES
48     	/* There is only the kernel to search.  */
49     	entry = search_one_table(__start___ex_table, __stop___ex_table - 1, addr, main_gp);
50     	if (entry)
51     		fix.cont = entry->cont + main_gp;
52     	return fix;
53     #else
54     	struct archdata *archdata;
55     	struct module *mp;
56     
57     	/* The kernel is the last "module" -- no need to treat it special. */
58     	for (mp = module_list; mp ; mp = mp->next) {
59     		if (!mp->ex_table_start)
60     			continue;
61     		archdata = (struct archdata *) mp->archdata_start;
62     		entry = search_one_table(mp->ex_table_start, mp->ex_table_end - 1,
63     					 addr, (unsigned long) archdata->gp);
64     		if (entry) {
65     			fix.cont = entry->cont + (unsigned long) archdata->gp;
66     			return fix;
67     		}
68     	}
69     #endif
70     	return fix;
71     }
72     
73     void
74     handle_exception (struct pt_regs *regs, struct exception_fixup fix)
75     {
76     	regs->r8 = -EFAULT;
77     	if (fix.cont & 4)
78     		regs->r9 = 0;
79     	regs->cr_iip = (long) fix.cont & ~0xf;
80     	ia64_psr(regs)->ri = fix.cont & 0x3;		/* set continuation slot number */
81     }
82