sh: Handle unaligned 16-bit instructions on SH-2A.

This adds some sanity checking in the unaligned instruction handler to
verify the instruction size, which enables basic support for 16-bit
fixups on SH-2A parts.

Signed-off-by: Paul Mundt <[e-mail]>

arch/sh/kernel/traps_32.c

···
 	u_int rm;
 	int ret, index;
 
+	/*
+	 * XXX: We can't handle mixed 16/32-bit instructions yet
+	 */
+	if (instruction_size(instruction) != 2)
+		return -EINVAL;
+
 	index = (instruction>>8)&15;	/* 0x0F00 */
 	rm = regs->regs[index];
 
···
 
 		se_user += 1;
 
-#ifndef CONFIG_CPU_SH2A
 		set_fs(USER_DS);
-		if (copy_from_user(&instruction, (u16 *)(regs->pc & ~1), 2)) {
+		if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
+				   sizeof(instruction))) {
 			set_fs(oldfs);
 			goto uspace_segv;
 		}
···
 			       "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
 			       current->comm, current->pid, (void *)regs->pc,
 			       instruction);
-#endif
 
 		if (se_usermode & 2)
 			goto fixup;