m68knommu: fix syscall restarting

Make restart blocks working, required for proper syscall restarting.
Derived from same changes for m68k arch by Andreas Schwab <[e-mail]>

Signed-off-by: Greg Ungerer <[e-mail]>

arch/m68knommu/kernel/signal.c

···
 	struct sigcontext context;
 	int err = 0;
 
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
 	/* get previous context */
 	if (copy_from_user(&context, usc, sizeof(context)))
 		goto badframe;
···
 	greg_t *gregs = uc->uc_mcontext.gregs;
 	unsigned long usp;
 	int err;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current_thread_info()->restart_block.fn = do_no_restart_syscall;
 
 	err = __get_user(temp, &uc->uc_mcontext.version);
 	if (temp != MCONTEXT_VERSION)
···
 	case -ERESTARTNOHAND:
 		if (!has_handler)
 			goto do_restart;
+		regs->d0 = -EINTR;
+		break;
+
+	case -ERESTART_RESTARTBLOCK:
+		if (!has_handler) {
+			regs->d0 = __NR_restart_syscall;
+			regs->pc -= 2;
+			break;
+		}
 		regs->d0 = -EINTR;
 		break;
 

arch/m68knommu/kernel/syscalltable.S

···
 .text
 ALIGN
 ENTRY(sys_call_table)
-	.long sys_ni_syscall	/* 0  -  old "setup()" system call*/
+	.long sys_restart_syscall	/* 0  -  old "setup()" system call */
 	.long sys_exit
 	.long sys_fork
 	.long sys_read