From bcb306aadd9fde6fc61126eceea1678f30ec68ec Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Mon, 8 Aug 2022 16:08:48 +0100
Subject: [PATCH] nios2: fix syscall restart checks

commit 2d631bd58fe0ea3e3350212e23c9aba1fb606514 upstream.

sys_foo() returns -512 (aka -ERESTARTSYS) => do_signal() sees
512 in r2 and 1 in r1.

sys_foo() returns 512 => do_signal() sees 512 in r2 and 0 in r1.

The former is restart-worthy; the latter obviously isn't.

Fixes: b53e906d255d ("nios2: Signal handling support")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/nios2/kernel/signal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/nios2/kernel/signal.c b/arch/nios2/kernel/signal.c
index 20662b0f6c9e..34588df93e35 100644
--- a/arch/nios2/kernel/signal.c
+++ b/arch/nios2/kernel/signal.c
@@ -240,7 +240,7 @@ static int do_signal(struct pt_regs *regs)
 	/*
 	 * If we were from a system call, check for system call restarting...
 	 */
-	if (regs->orig_r2 >= 0) {
+	if (regs->orig_r2 >= 0 && regs->r1) {
 		continue_addr = regs->ea;
 		restart_addr = continue_addr - 4;
 		retval = regs->r2;