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 4B64AC636CE for ; Mon, 19 Jul 2021 17:08:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 289AB61019 for ; Mon, 19 Jul 2021 17:08:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351892AbhGSQZK (ORCPT ); Mon, 19 Jul 2021 12:25:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:49596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346612AbhGSPO5 (ORCPT ); Mon, 19 Jul 2021 11:14:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C494D60FE9; Mon, 19 Jul 2021 15:55:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626710134; bh=OU7RHW8RCJ20JtwD/Ek2scsCmITqJZlaW4FZJH/iKEk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Eg8vWmwcqCUwa+kuNhoO0qv4typnX24YPDyUVyNOhUkX7knLYEwlnMWFSrZEX2vLs d/zAsjuOcsr2l380wb9OPctKk/RemUlIencaIoZYFKV7Qz1YcY+ML1E4ItZUsmDEi+ oihAEA260S5IGPNwV4IIuV8HAZRqbh5ICCXHSj0A= 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 5.10 090/243] s390/mem_detect: fix tprot() program check new psw handling Date: Mon, 19 Jul 2021 16:51:59 +0200 Message-Id: <20210719144943.799030742@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144940.904087935@linuxfoundation.org> References: <20210719144940.904087935@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 da9057576785aaab52e706e76c0475c85b77ec14 ] The tprot() 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 | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/arch/s390/boot/mem_detect.c b/arch/s390/boot/mem_detect.c index 032d68165216..85049541c191 100644 --- a/arch/s390/boot/mem_detect.c +++ b/arch/s390/boot/mem_detect.c @@ -115,24 +115,30 @@ static int diag260(void) static int tprot(unsigned long addr) { - unsigned long pgm_addr; + unsigned long reg1, reg2; int rc = -EFAULT; - psw_t old = S390_lowcore.program_new_psw; + psw_t old; - S390_lowcore.program_new_psw.mask = __extract_psw(); asm volatile( - " larl %[pgm_addr],1f\n" - " stg %[pgm_addr],%[psw_pgm_addr]\n" + " mvc 0(16,%[psw_old]),0(%[psw_pgm])\n" + " epsw %[reg1],%[reg2]\n" + " st %[reg1],0(%[psw_pgm])\n" + " st %[reg2],4(%[psw_pgm])\n" + " larl %[reg1],1f\n" + " stg %[reg1],8(%[psw_pgm])\n" " tprot 0(%[addr]),0\n" " ipm %[rc]\n" " srl %[rc],28\n" - "1:\n" - : [pgm_addr] "=&d"(pgm_addr), - [psw_pgm_addr] "=Q"(S390_lowcore.program_new_psw.addr), - [rc] "+&d"(rc) - : [addr] "a"(addr) + "1: mvc 0(16,%[psw_pgm]),0(%[psw_old])\n" + : [reg1] "=&d" (reg1), + [reg2] "=&a" (reg2), + [rc] "+&d" (rc), + "=Q" (S390_lowcore.program_new_psw.addr), + "=Q" (old) + : [psw_old] "a" (&old), + [psw_pgm] "a" (&S390_lowcore.program_new_psw), + [addr] "a" (addr) : "cc", "memory"); - S390_lowcore.program_new_psw = old; return rc; } -- 2.30.2