diff options
Diffstat (limited to 'arch/sh/mm/extable_64.c')
-rw-r--r-- | arch/sh/mm/extable_64.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/arch/sh/mm/extable_64.c b/arch/sh/mm/extable_64.c new file mode 100644 index 00000000000..a2e6e056377 --- /dev/null +++ b/arch/sh/mm/extable_64.c @@ -0,0 +1,80 @@ +/* + * 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; +} + |