From patchwork Mon Jul 19 14:52:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 480458 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 736E6C6377E for ; Mon, 19 Jul 2021 16:26:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 52F366192C for ; Mon, 19 Jul 2021 16:26:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236323AbhGSPqK (ORCPT ); Mon, 19 Jul 2021 11:46:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:43678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348352AbhGSPmp (ORCPT ); Mon, 19 Jul 2021 11:42:45 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9238F613EE; Mon, 19 Jul 2021 16:21:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626711720; bh=D8wE6hMjQTlUe9QWH2Md16qINHYcgAlC8HKXj4ZNvMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VlQtfuJ5sMMWxJyOF8w5W5ltNxPQNpDsHZugrf4UtAF3bK6adHEUWj1sMA9By5FSx vCg0xrsbG1EMhLe/ULGicj1l1lW+pLNCnWRxUfi7udfNzjhrg9hHMa5F6z4KASy27V vP8M7yOx5hUVsv819yYILxW6Ic2OdSehwivoguKI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Sasha Levin Subject: [PATCH 5.12 107/292] s390/ipl_parm: fix program check new psw handling Date: Mon, 19 Jul 2021 16:52:49 +0200 Message-Id: <20210719144946.016010110@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144942.514164272@linuxfoundation.org> References: <20210719144942.514164272@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Heiko Carstens [ Upstream commit 88c2510cecb7e2b518e3c4fdf3cf0e13ebe9377c ] The __diag308() inline asm temporarily changes the program check new psw to redirect a potential program check on the diag instruction. Restoring of the program check new psw is done in C code behind the inline asm. This can be problematic, especially if the function is inlined, since the compiler can reorder instructions in such a way that a different instruction, which may result in a program check, might be executed before the program check new psw has been restored. To avoid such a scenario move restoring into the inline asm. For consistency reasons move also saving of the original program check new psw into the inline asm. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- arch/s390/boot/ipl_parm.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c index d372a45fe10e..dd92092e3eec 100644 --- a/arch/s390/boot/ipl_parm.c +++ b/arch/s390/boot/ipl_parm.c @@ -28,22 +28,25 @@ static inline int __diag308(unsigned long subcode, void *addr) register unsigned long _addr asm("0") = (unsigned long)addr; register unsigned long _rc asm("1") = 0; unsigned long reg1, reg2; - psw_t old = S390_lowcore.program_new_psw; + psw_t old; asm volatile( + " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n" " epsw %0,%1\n" - " st %0,%[psw_pgm]\n" - " st %1,%[psw_pgm]+4\n" + " st %0,0(%[psw_pgm])\n" + " st %1,4(%[psw_pgm])\n" " larl %0,1f\n" - " stg %0,%[psw_pgm]+8\n" + " stg %0,8(%[psw_pgm])\n" " diag %[addr],%[subcode],0x308\n" - "1: nopr %%r7\n" + "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n" : "=&d" (reg1), "=&a" (reg2), - [psw_pgm] "=Q" (S390_lowcore.program_new_psw), + "+Q" (S390_lowcore.program_new_psw), + "=Q" (old), [addr] "+d" (_addr), "+d" (_rc) - : [subcode] "d" (subcode) + : [subcode] "d" (subcode), + [psw_old] "a" (&old), + [psw_pgm] "a" (&S390_lowcore.program_new_psw) : "cc", "memory"); - S390_lowcore.program_new_psw = old; return _rc; }