mirror of https://gitee.com/openkylin/linux.git
81 lines
2.1 KiB
C
81 lines
2.1 KiB
C
|
/*
|
||
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
||
|
|
* License. See the file "COPYING" in the main directory of this archive
|
||
|
|
* for more details.
|
||
|
|
*
|
||
|
|
* arch/sh64/mm/extable.c
|
||
|
|
*
|
||
|
|
* Copyright (C) 2003 Richard Curnow
|
||
|
|
* Copyright (C) 2003, 2004 Paul Mundt
|
||
|
|
*
|
||
|
|
* Cloned from the 2.5 SH version..
|
||
|
|
*/
|
||
|
|
#include <linux/rwsem.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <asm/uaccess.h>
|
||
|
|
|
||
|
|
extern unsigned long copy_user_memcpy, copy_user_memcpy_end;
|
||
|
|
extern void __copy_user_fixup(void);
|
||
|
|
|
||
|
|
static const struct exception_table_entry __copy_user_fixup_ex = {
|
||
|
|
.fixup = (unsigned long)&__copy_user_fixup,
|
||
|
|
};
|
||
|
|
|
||
|
|
/* Some functions that may trap due to a bad user-mode address have too many loads
|
||
|
|
and stores in them to make it at all practical to label each one and put them all in
|
||
|
|
the main exception table.
|
||
|
|
|
||
|
|
In particular, the fast memcpy routine is like this. It's fix-up is just to fall back
|
||
|
|
to a slow byte-at-a-time copy, which is handled the conventional way. So it's functionally
|
||
|
|
OK to just handle any trap occurring in the fast memcpy with that fixup. */
|
||
|
|
static const struct exception_table_entry *check_exception_ranges(unsigned long addr)
|
||
|
|
{
|
||
|
|
if ((addr >= (unsigned long)©_user_memcpy) &&
|
||
|
|
(addr <= (unsigned long)©_user_memcpy_end))
|
||
|
|
return &__copy_user_fixup_ex;
|
||
|
|
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* Simple binary search */
|
||
|
|
const struct exception_table_entry *
|
||
|
|
search_extable(const struct exception_table_entry *first,
|
||
|
|
const struct exception_table_entry *last,
|
||
|
|
unsigned long value)
|
||
|
|
{
|
||
|
|
const struct exception_table_entry *mid;
|
||
|
|
|
||
|
|
mid = check_exception_ranges(value);
|
||
|
|
if (mid)
|
||
|
|
return mid;
|
||
|
|
|
||
|
|
while (first <= last) {
|
||
|
|
long diff;
|
||
|
|
|
||
|
|
mid = (last - first) / 2 + first;
|
||
|
|
diff = mid->insn - value;
|
||
|
|
if (diff == 0)
|
||
|
|
return mid;
|
||
|
|
else if (diff < 0)
|
||
|
|
first = mid+1;
|
||
|
|
else
|
||
|
|
last = mid-1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return NULL;
|
||
|
|
}
|
||
|
|
|
||
|
|
int fixup_exception(struct pt_regs *regs)
|
||
|
|
{
|
||
|
|
const struct exception_table_entry *fixup;
|
||
|
|
|
||
|
|
fixup = search_exception_tables(regs->pc);
|
||
|
|
if (fixup) {
|
||
|
|
regs->pc = fixup->fixup;
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|