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kernel add
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/*
* arch/sh/mm/extable_64.c
*
* Copyright (C) 2003 Richard Curnow
* Copyright (C) 2003, 2004 Paul Mundt
*
* Cloned from the 2.5 SH version..
*
* 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.
*/
#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;
}
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