From mboxrd@z Thu Jan 1 00:00:00 1970 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=unavailable 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 88448C07E9B for ; Mon, 19 Jul 2021 18:02:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6535A60FF3 for ; Mon, 19 Jul 2021 18:02:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355649AbhGSRVy (ORCPT ); Mon, 19 Jul 2021 13:21:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:43962 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348160AbhGSPm6 (ORCPT ); Mon, 19 Jul 2021 11:42:58 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B882F6128C; Mon, 19 Jul 2021 16:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626711725; bh=ZP9KQES+HDuOGeyqR9cpbVw/7pbTbMeag+0gntsBwL4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IGhHRJHLI0TlendpBEpbSGqcGmdA4b8Ol8/uHAVnRcjV5k0uPS+K912rkxlwaUzG1 juO8e0tkNazefPy+FPntiqLLTpWGVvPLPm90wfP3THTUlWEcsRb5FejkXoBXy1kvQE 4p+UXmoal44zL8Bhbx9DcJvNERHVjx0HPWNjxAKo= 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 5.12 108/292] s390/mem_detect: fix diag260() program check new psw handling Date: Mon, 19 Jul 2021 16:52:50 +0200 Message-Id: <20210719144946.045831472@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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Heiko Carstens [ Upstream commit 86807f348f418a84970eebb8f9912a7eea16b497 ] The __diag260() 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/mem_detect.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c index 40168e59abd3..3f093556dc3b 100644 --- a/arch/s390/boot/mem_detect.c +++ b/arch/s390/boot/mem_detect.c @@ -69,24 +69,27 @@ static int __diag260(unsigned long rx1, unsigned long rx2) register unsigned long _ry asm("4") = 0x10; /* storage configuration */ int rc = -1; /* fail */ 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 %[rx],%[ry],0x260\n" " ipm %[rc]\n" " srl %[rc],28\n" - "1:\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), [rc] "+&d" (rc), [ry] "+d" (_ry) - : [rx] "d" (_rx1), "d" (_rx2) + : [rx] "d" (_rx1), "d" (_rx2), + [psw_old] "a" (&old), + [psw_pgm] "a" (&S390_lowcore.program_new_psw) : "cc", "memory"); - S390_lowcore.program_new_psw = old; return rc == 0 ? _ry : -1; } -- 2.30.2