m68k: Wire up sys_restart_syscall

Make restart blocks working, required for proper syscall restarting.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/kernel/entry.S

@@ -424,7 +424,7 @@ resume:
 .data
 ALIGN
 sys_call_table:
-	.long sys_ni_syscall	/* 0  -  old "setup()" system call*/
+	.long sys_restart_syscall	/* 0 - old "setup()" system call, used for restarting */
 	.long sys_exit
 	.long sys_fork
 	.long sys_read

arch/m68k/kernel/signal.c

@@ -326,6 +326,9 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __u
 	struct sigcontext context;
 	int err;
 
+	/* 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;
@@ -411,6 +414,9 @@ rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
 	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)
 		goto badframe;
@@ -937,6 +943,15 @@ handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
 		regs->d0 = -EINTR;
 		break;
 
+	case -ERESTART_RESTARTBLOCK:
+		if (!has_handler) {
+			regs->d0 = __NR_restart_syscall;
+			regs->pc -= 2;
+			break;
+		}
+		regs->d0 = -EINTR;
+		break;
+
 	case -ERESTARTSYS:
 		if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
 			regs->d0 = -EINTR;

include/asm-m68k/unistd.h

@@ -5,6 +5,7 @@
  * This file contains the system call numbers.
  */
 
+#define __NR_restart_syscall	  0
 #define __NR_exit		  1
 #define __NR_fork		  2
 #define __NR_read		  3
@@ -359,9 +360,6 @@
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_RT_SIGACTION
 
-/* whitelist for checksyscalls */
-#define __IGNORE_restart_syscall
-
 /*
  * "Conditional" syscalls
  *