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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 E3470C169C4 for ; Wed, 6 Feb 2019 18:05:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6FB320821 for ; Wed, 6 Feb 2019 18:05:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729741AbfBFSF1 (ORCPT ); Wed, 6 Feb 2019 13:05:27 -0500 Received: from terminus.zytor.com ([198.137.202.136]:57835 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726727AbfBFSF0 (ORCPT ); Wed, 6 Feb 2019 13:05:26 -0500 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id x16I4Dxv1387757 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Wed, 6 Feb 2019 10:04:13 -0800 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id x16I4BnF1387753; Wed, 6 Feb 2019 10:04:11 -0800 Date: Wed, 6 Feb 2019 10:04:11 -0800 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: "tip-bot for Kirill A. Shutemov" Message-ID: Cc: kyle.d.pelton@intel.com, mingo@redhat.com, x86@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, bp@suse.de, wei@redhat.com, mingo@kernel.org, tglx@linutronix.de, kirill.shutemov@linux.intel.com Reply-To: kyle.d.pelton@intel.com, x86@kernel.org, hpa@zytor.com, mingo@redhat.com, linux-kernel@vger.kernel.org, bp@suse.de, wei@redhat.com, mingo@kernel.org, tglx@linutronix.de, kirill.shutemov@linux.intel.com In-Reply-To: <20190206115253.1907-1-kirill.shutemov@linux.intel.com> References: <20190206115253.1907-1-kirill.shutemov@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/boot/compressed/64: Do not corrupt EDX on EFER.LME=1 setting Git-Commit-ID: 45b13b424faafb81c8c44541f093a682fdabdefc X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 45b13b424faafb81c8c44541f093a682fdabdefc Gitweb: https://git.kernel.org/tip/45b13b424faafb81c8c44541f093a682fdabdefc Author: Kirill A. Shutemov AuthorDate: Wed, 6 Feb 2019 14:52:53 +0300 Committer: Borislav Petkov CommitDate: Wed, 6 Feb 2019 18:56:18 +0100 x86/boot/compressed/64: Do not corrupt EDX on EFER.LME=1 setting RDMSR in the trampoline code overwrites EDX but that register is used to indicate whether 5-level paging has to be enabled and if clobbered, leads to failure to boot on a 5-level paging machine. Preserve EDX on the stack while we are dealing with EFER. Fixes: b677dfae5aa1 ("x86/boot/compressed/64: Set EFER.LME=1 in 32-bit trampoline before returning to long mode") Reported-by: Kyle D Pelton Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov Cc: dave.hansen@linux.intel.com Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Wei Huang Cc: x86-ml Link: https://lkml.kernel.org/r/20190206115253.1907-1-kirill.shutemov@linux.intel.com --- arch/x86/boot/compressed/head_64.S | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index f105ae8651c9..f62e347862cc 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -602,10 +602,12 @@ ENTRY(trampoline_32bit_src) 3: /* Set EFER.LME=1 as a precaution in case hypervsior pulls the rug */ pushl %ecx + pushl %edx movl $MSR_EFER, %ecx rdmsr btsl $_EFER_LME, %eax wrmsr + popl %edx popl %ecx /* Enable PAE and LA57 (if required) paging modes */