From patchwork Sun Feb 2 17:13:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arvind Sankar X-Patchwork-Id: 206603 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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=no 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 20B10C35249 for ; Sun, 2 Feb 2020 17:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E871320679 for ; Sun, 2 Feb 2020 17:13:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726906AbgBBRN4 (ORCPT ); Sun, 2 Feb 2020 12:13:56 -0500 Received: from mail-qk1-f195.google.com ([209.85.222.195]:37996 "EHLO mail-qk1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726525AbgBBRN4 (ORCPT ); Sun, 2 Feb 2020 12:13:56 -0500 Received: by mail-qk1-f195.google.com with SMTP id k6so11929958qki.5; Sun, 02 Feb 2020 09:13:55 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=wkB9hEzJnTGg0+titOdjnKOkA5bK07ut9KDYjyipcyQ=; b=XLwYkWNir2DWBtBW7uyPEqO1le1ovip+CWBmdvJivK6P7lopltFO/ZaaQmsxG8soLD cgt6MVmvjH3TEFy7IjJryoYQuEHBo3tROOXlQXwnZPuyWBjUrKgZLWusKy0WjxIkEauJ GXx/0k22r9lnLa4QYBamM0RDElfr3mGnHJ8uocI6UoXoSTEsIWqxzEXxvLPTUBvcZx/I xQ4n3pZB6tNZQ3W02tKHev4PTfqNACYF7xcG+P/D7/f2nLCoCa6AMO1M+ioxVFzUQ0gO /SBcZNPxE6sDeL/0olMZtQY1VE3Wj1w9f5scUEkS4sOSB4SvfCEpCj5OM8KaG5QsqLoy 2MEg== X-Gm-Message-State: APjAAAXs2k/33ouLDQMC9dlOdaJJDQ9Daiz106Lcj1txE61RKZEJ+MM1 79db2ldW8qbITXniJN0sSgk= X-Google-Smtp-Source: APXvYqy6GSEPqc154do67Yx2BRzju/BO1xu6ATlNJHsqHsL2qBR8epiNbj/7XivSIA4CxHRVd7RRow== X-Received: by 2002:a37:be07:: with SMTP id o7mr5554219qkf.392.1580663634734; Sun, 02 Feb 2020 09:13:54 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id 3sm8150081qte.59.2020.02.02.09.13.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 02 Feb 2020 09:13:54 -0800 (PST) From: Arvind Sankar To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Ard Biesheuvel Cc: linux-efi@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/7] x86/efi,boot: GDT handling cleanup/fixes Date: Sun, 2 Feb 2020 12:13:46 -0500 Message-Id: <20200202171353.3736319-1-nivedita@alum.mit.edu> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200130200440.1796058-1-nivedita@alum.mit.edu> References: <20200130200440.1796058-1-nivedita@alum.mit.edu> MIME-Version: 1.0 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org This series fixes a potential bug in EFI mixed-mode and leaves GDT handling to startup_{32,64} instead of efi_main. The first patch removes KEEP_SEGMENTS support in loadflags, this is unused now (details in patch 1 commit msg), to slightly simplify subsequent changes. The second patch fixes a potential bug in EFI mixed-mode, where we are currently relying on the firmware GDT having a particular layout: a CODE32 segment as descriptor 2 and a DATA segment as descriptor 3. The third patch adds some safety during kernel decompression by updating the GDTR to point to the copied GDT, rather than the old one which may have been overwritten. The fourth patch adds cld/cli to startup_64, and the fifth patch removes all the GDT setup from efi_main and adds it to the 32-bit kernel's startup_32. The 64-bit kernel already does GDT setup. This should be safer as this code can keep track of where the .data section is moving and ensure that GDTR is pointing to a clean copy of the GDT. The last two patches are to fix an off-by-one in the GDT limit and do a micro-optimization to the GDT loading instructions. Changes from v1: - added removal of KEEP_SEGMENTS - added the mixed-mode fix - completely removed GDT setup from efi_main, including for the 32-bit kernel - dropped documentation patches for now Arvind Sankar (7): x86/boot: Remove KEEP_SEGMENTS support efi/x86: Don't depend on firmware GDT layout x86/boot: Reload GDTR after copying to the end of the buffer x86/boot: Clear direction and interrupt flags in startup_64 efi/x86: Remove GDT setup from efi_main x86/boot: GDT limit value should be size - 1 x86/boot: Micro-optimize GDT loading instructions Documentation/x86/boot.rst | 8 +- arch/x86/boot/compressed/eboot.c | 103 ------------------------ arch/x86/boot/compressed/efi_thunk_64.S | 29 +++++-- arch/x86/boot/compressed/head_32.S | 48 +++++++---- arch/x86/boot/compressed/head_64.S | 66 ++++++++------- arch/x86/kernel/head_32.S | 6 -- 6 files changed, 99 insertions(+), 161 deletions(-)