Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc

Pull sparc fix from David Miller:
 "Bug fix from Al Viro"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc64: not any error from do_sigaltstack() should fail rt_sigreturn()

arch/sparc/kernel/signal_64.c

@@ -295,9 +295,7 @@ void do_rt_sigreturn(struct pt_regs *regs)
 		err |= restore_fpu_state(regs, fpu_save);
 
 	err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
-	err |= do_sigaltstack(&sf->stack, NULL, (unsigned long)sf);
-
-	if (err)
+	if (err || do_sigaltstack(&sf->stack, NULL, (unsigned long)sf) == -EFAULT)
 		goto segv;
 
 	err |= __get_user(rwin_save, &sf->rwin_save);