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Commit 2afb447f authored by SUGIOKA Toshinobu's avatar SUGIOKA Toshinobu Committed by Paul Mundt
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sh: fix unaligned and nonexistent address handling 



unaligned and nonexistent address causes wrong exception
handling in traps_32.c(handle_unaligned_access).

'handle_unalinged_ins' should return -EFAULT if address error
is fixed up with kernel exception table, otherwise
'handle_unaligned_access' increases already fixed program counter
and then crash.

for example
   ioctl(fd, TCGETA, (struct termio *)-1)
never return and stay in TASK_UNINTERRUPTIBLE state forever
in my kernel.

Signed-off-by: default avatarSUGIOKA Toshinobu <sugioka@itonet.co.jp>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent eb6434d9

arch/sh/kernel/traps_32.c

+4 −5
Original line number Diff line number Diff line
@@ -125,20 +125,18 @@ static inline void die_if_kernel(const char *str, struct pt_regs *regs, 
 * - userspace errors just cause EFAULT to be returned, resulting in SEGV

 * - kernel/userspace interfaces cause a jump to an appropriate handler

 * - other kernel errors are bad

 * - return 0 if fixed-up, -EFAULT if non-fatal (to the kernel) fault

 */

static int die_if_no_fixup(const char * str, struct pt_regs * regs, long err)

static void die_if_no_fixup(const char * str, struct pt_regs * regs, long err)

{

	if (!user_mode(regs)) {

		const struct exception_table_entry *fixup;

		fixup = search_exception_tables(regs->pc);

		if (fixup) {

			regs->pc = fixup->fixup;

			return 0;

			return;

		}

		die(str, regs, err);

	}

	return -EFAULT;

}



static inline void sign_extend(unsigned int count, unsigned char *dst)
@@ -314,7 +312,8 @@ static int handle_unaligned_ins(opcode_t instruction, struct pt_regs *regs, 
	/* Argh. Address not only misaligned but also non-existent.

	 * Raise an EFAULT and see if it's trapped

	 */

	return die_if_no_fixup("Fault in unaligned fixup", regs, 0);

	die_if_no_fixup("Fault in unaligned fixup", regs, 0);

	return -EFAULT;

}



/*