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/*
* 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;
}
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