blob: 7a3b4d33d2e7d2f591c437b7240e29368b3fda5c [file] [log] [blame]
* 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/bsearch.h>
#include <linux/rwsem.h>
#include <linux/extable.h>
#include <linux/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)&copy_user_memcpy) &&
(addr <= (unsigned long)&copy_user_memcpy_end))
return &__copy_user_fixup_ex;
return NULL;
static int cmp_ex_search(const void *key, const void *elt)
const struct exception_table_entry *_elt = elt;
unsigned long _key = *(unsigned long *)key;
/* avoid overflow */
if (_key > _elt->insn)
return 1;
if (_key < _elt->insn)
return -1;
return 0;
/* Simple binary search */
const struct exception_table_entry *
search_extable(const struct exception_table_entry *base,
const size_t num,
unsigned long value)
const struct exception_table_entry *mid;
mid = check_exception_ranges(value);
if (mid)
return mid;
return bsearch(&value, base, num,
sizeof(struct exception_table_entry), cmp_ex_search);
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;