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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 6C682C2D0DA for ; Wed, 25 Dec 2019 10:39:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43C6A2077B for ; Wed, 25 Dec 2019 10:39:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727030AbfLYKjI (ORCPT ); Wed, 25 Dec 2019 05:39:08 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:40583 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726369AbfLYKjE (ORCPT ); Wed, 25 Dec 2019 05:39:04 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1ik446-000864-Mh; Wed, 25 Dec 2019 11:38:54 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 5CD941C2B1E; Wed, 25 Dec 2019 11:38:54 +0100 (CET) Date: Wed, 25 Dec 2019 10:38:54 -0000 From: "tip-bot2 for Ard Biesheuvel" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: efi/urgent] x86/efistub: Disable paging at mixed mode entry Cc: Ard Biesheuvel , , Arvind Sankar , Hans de Goede , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-efi@vger.kernel.org, Ingo Molnar , x86 , LKML In-Reply-To: <20191224132909.102540-4-ardb@kernel.org> References: <20191224132909.102540-4-ardb@kernel.org> MIME-Version: 1.0 Message-ID: <157727033419.30329.4854144376331074852.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the efi/urgent branch of tip: Commit-ID: 4911ee401b7ceff8f38e0ac597cbf503d71e690c Gitweb: https://git.kernel.org/tip/4911ee401b7ceff8f38e0ac597cbf503d71e690c Author: Ard Biesheuvel AuthorDate: Tue, 24 Dec 2019 14:29:09 +01:00 Committer: Ingo Molnar CommitterDate: Wed, 25 Dec 2019 10:46:07 +01:00 x86/efistub: Disable paging at mixed mode entry The EFI mixed mode entry code goes through the ordinary startup_32() routine before jumping into the kernel's EFI boot code in 64-bit mode. The 32-bit startup code must be entered with paging disabled, but this is not documented as a requirement for the EFI handover protocol, and so we should disable paging explicitly when entering the kernel from 32-bit EFI firmware. Signed-off-by: Ard Biesheuvel Cc: Cc: Arvind Sankar Cc: Hans de Goede Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-efi@vger.kernel.org Link: https://lkml.kernel.org/r/20191224132909.102540-4-ardb@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/head_64.S | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S index 58a512e..ee60b81 100644 --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -244,6 +244,11 @@ SYM_FUNC_START(efi32_stub_entry) leal efi32_config(%ebp), %eax movl %eax, efi_config(%ebp) + /* Disable paging */ + movl %cr0, %eax + btrl $X86_CR0_PG_BIT, %eax + movl %eax, %cr0 + jmp startup_32 SYM_FUNC_END(efi32_stub_entry) #endif