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>
        /*
         * 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;