From patchwork Wed Jan 22 09:27:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 206612 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=-5.7 required=3.0 tests=DATE_IN_PAST_03_06, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 2BCBDC2D0DB for ; Wed, 22 Jan 2020 13:31:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F335820704 for ; Wed, 22 Jan 2020 13:31:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579699891; bh=RSUDhfPhXk0dWiZ10UxNgdPkWdvoHWDWWByQvoZi8Lo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mFdhBZmnsNXu/P2U1ITTpRjnsqc7g+VKENxUQY1dZwe7A0Nvo28CxcQ6K4GwgTCs9 2WQFHqLc0Ge6wfWAH2WVay6hArXEjXXiGzNzuXi6A3bAiHxkyEyZ2ulPgfgni3ulGR xKnVmtlRIO4Cl8qPtlgQwdP4t/Wq2YPvYRCaI91E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729799AbgAVNTt (ORCPT ); Wed, 22 Jan 2020 08:19:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:35808 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728811AbgAVNTr (ORCPT ); Wed, 22 Jan 2020 08:19:47 -0500 Received: from localhost (unknown [84.241.205.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4861820678; Wed, 22 Jan 2020 13:19:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579699186; bh=RSUDhfPhXk0dWiZ10UxNgdPkWdvoHWDWWByQvoZi8Lo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yeOfO4omESxdLvcUs6gqyvwKYXhk3SJdL8/Ynx5bKc2MIUaAk0U9XcX/x+EF/TSos eV8Pyr5t4R3g/BiezgWxRXyS5nR4Og8zYT2Yz+uwXXIfxUtV9n66xPb1CPiIigEQJT HgGeVx2L7iCe3h0qSCzzwYCzZ5xL6QkbdknCOr2M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ard Biesheuvel , Arvind Sankar , Hans de Goede , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , linux-efi@vger.kernel.org, Ingo Molnar Subject: [PATCH 5.4 066/222] x86/efistub: Disable paging at mixed mode entry Date: Wed, 22 Jan 2020 10:27:32 +0100 Message-Id: <20200122092838.449657394@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200122092833.339495161@linuxfoundation.org> References: <20200122092833.339495161@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org From: Ard Biesheuvel commit 4911ee401b7ceff8f38e0ac597cbf503d71e690c upstream. 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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/boot/compressed/head_64.S | 5 +++++ 1 file changed, 5 insertions(+) --- a/arch/x86/boot/compressed/head_64.S +++ b/arch/x86/boot/compressed/head_64.S @@ -244,6 +244,11 @@ ENTRY(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 ENDPROC(efi32_stub_entry) #endif