summaryrefslogtreecommitdiff
path: root/arch/frv/mm/extable.c
blob: 9198ddd16092107e98aa2a94d89fade42fe41dd4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
/*
 * linux/arch/frv/mm/extable.c
 */

#include <linux/extable.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>

extern const void __memset_end, __memset_user_error_lr, __memset_user_error_handler;
extern const void __memcpy_end, __memcpy_user_error_lr, __memcpy_user_error_handler;
extern spinlock_t modlist_lock;

int fixup_exception(struct pt_regs *regs)
{
	const struct exception_table_entry *extab;
	unsigned long pc = regs->pc;

	/* determine if the fault lay during a memcpy_user or a memset_user */
	if (regs->lr == (unsigned long) &__memset_user_error_lr &&
	    (unsigned long) &memset <= pc && pc < (unsigned long) &__memset_end
	    ) {
		/* the fault occurred in a protected memset
		 * - we search for the return address (in LR) instead of the program counter
		 * - it was probably during a clear_user()
		 */
		regs->pc = (unsigned long) &__memset_user_error_handler;
		return 1;
	}

	if (regs->lr == (unsigned long) &__memcpy_user_error_lr &&
	    (unsigned long) &memcpy <= pc && pc < (unsigned long) &__memcpy_end
	    ) {
		/* the fault occurred in a protected memset
		 * - we search for the return address (in LR) instead of the program counter
		 * - it was probably during a copy_to/from_user()
		 */
		regs->pc = (unsigned long) &__memcpy_user_error_handler;
		return 1;
	}

	extab = search_exception_tables(pc);
	if (extab) {
		regs->pc = extab->fixup;
		return 1;
	}

	return 0;
}