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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 A4A58C169C4 for ; Mon, 11 Feb 2019 09:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6372320863 for ; Mon, 11 Feb 2019 09:57:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="GtjEJO2O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726378AbfBKJ5O (ORCPT ); Mon, 11 Feb 2019 04:57:14 -0500 Received: from mail-it1-f195.google.com ([209.85.166.195]:51132 "EHLO mail-it1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726079AbfBKJ5O (ORCPT ); Mon, 11 Feb 2019 04:57:14 -0500 Received: by mail-it1-f195.google.com with SMTP id z7so24875123iti.0 for ; Mon, 11 Feb 2019 01:57:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yn3LX26QvHVsiLYSnhIRA+BhZv857IBuSZZW4F03zJU=; b=GtjEJO2O0FTnAHiFl9DDpfqSrUHd+2r0K/PGNbayWdUKxnK10FTK/8BJzYAxImT7W8 StelEswMsuhfTxq+fET1UQ4/8xdUMkZn7LtCD8NjaSS9Ayr90wEJekWJL1G10h5PESBl kZqlL3bO6oK6lGXTkFktsGzzO2yWgQ+S33RFWXefppSi15Za3pXupuBy1yHa3fnxwqHQ e4ewaeSGZ1HKGmW1xce85MZHfkapZhciQF4Qbryov69OOcg5icJdOrvKzWHbKFCHckm6 u1OixF/Y7UGYXOzwnZejZWFLgCLeRSXcj6omrg45oOf+5vrh+qzCxvtf51r3whvIYcUk e1rA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yn3LX26QvHVsiLYSnhIRA+BhZv857IBuSZZW4F03zJU=; b=K1UsPSNxb/RQzKa/yhqL67uPDqfAhZUjluax47nDzRx2rv3TKpfH1EDE/jurIIOcwU 2j0vzYsRkUt7EgZcwuh0COjdfo3pR09DI9x/oMS4gHI12S5iX/5Wi2dSrQCnVJAf8G09 m7Hfi+ef59tiMuIFAXAyiR6bvx9YmoD8w87uoNhXAr0/0C0uKoPlOxe2kjLg/V2EcN1l UfhcXKCRl2upUM2qELBQM1o/tMnOIw0SEC++VWrmvBU4COTbPrnxEgs+GfzKKGNkZEpZ 2DcBb9n4dBkWe+kKeS635RpLl8xSwq1RMJWzaw/l++ZKKCgks8SKRvMO/XZSMAAGxDLl +9jg== X-Gm-Message-State: AHQUAuZp8lX1hMVV8EMv+CQHS50u8hQ4QXi28dDF3ouuAvrvpmfjTcMn 8i/6arghZeyoD0Jrskh9Mo4LBpLR883GbmUCCzTg2g== X-Google-Smtp-Source: AHgI3IaKRM4tKpi2/dQ8NMKdFDJyT9xJFvaJHkE3gKOzigQ9/Hidge8HkiP/wrGMUqs0JspsMkMoDxrvKfIH28RgY/o= X-Received: by 2002:a02:15da:: with SMTP id 87mr348340jaq.2.1549879033350; Mon, 11 Feb 2019 01:57:13 -0800 (PST) MIME-Version: 1.0 References: <20190123110850.12433-6-fanc.fnst@cn.fujitsu.com> <20190208190248.GA10854@roeck-us.net> <20190208191024.GL674@zn.tnic> <20190208204451.GA14024@roeck-us.net> <20190208215322.GO674@zn.tnic> <20190211002220.GD14948@zn.tnic> <20190211095547.GB1651@localhost.localdomain> In-Reply-To: <20190211095547.GB1651@localhost.localdomain> From: Ard Biesheuvel Date: Mon, 11 Feb 2019 09:57:02 +0000 Message-ID: Subject: Re: [tip:x86/boot] x86/boot: Early parse RSDP and save it in boot_params To: Chao Fan Cc: Borislav Petkov , Guenter Roeck , Thomas Gleixner , Linux Kernel Mailing List , "Kirill A. Shutemov" , Ingo Molnar , "Lendacky, Thomas" , Masahiro Yamada , caoj.fnst@cn.fujitsu.com, Juergen Gross , Ingo Molnar , Kees Cook , "the arch/x86 maintainers" , "H. Peter Anvin" , linux-tip-commits@vger.kernel.org, Matt Fleming Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 11 Feb 2019 at 10:56, Chao Fan wrote: > > On Mon, Feb 11, 2019 at 09:46:03AM +0000, Ard Biesheuvel wrote: > >On Mon, 11 Feb 2019 at 01:22, Borislav Petkov wrote: > >> > >> On Fri, Feb 08, 2019 at 10:53:22PM +0100, Borislav Petkov wrote: > >> > On Fri, Feb 08, 2019 at 12:44:51PM -0800, Guenter Roeck wrote: > >> > > Yes, the kernel boots if I comment out that function and have it return 0. > >> > > >> > Thanks, this localizes the issue significantly. > >> > >> Some observations: > >> > >> } else { > >> efi_config_table_32_t *tmp_table; > >> > >> tmp_table = config_tables; > >> guid = tmp_table->guid; <--- * > >> table = tmp_table->table; > >> } > >> > >> It blows up at that tmp_table->guid deref above. Singlestepping through > >> it with gdb shows: > >> > >> # arch/x86/boot/compressed/acpi.c:114: guid = tmp_table->guid; > >> movq (%rdi), %rax # MEM[(struct efi_config_table_32_t *)config_tables_37].guid, guid > >> movq 8(%rdi), %rsi # MEM[(struct efi_config_table_32_t *)config_tables_37].guid, guid > >> # arch/x86/boot/compressed/acpi.c:115: table = tmp_table->table; > >> movl 16(%rdi), %r10d # MEM[(struct efi_config_table_32_t *)config_tables_37].table, table > >> jmp .L30 # > >> > >> and %rdi has: > >> > >> rdi 0x630646870 > >> > >> which is an address above 4G but we're using a 32-bit EFI BIOS. > >> > >> Which begs the question whether EFI system tables can even be mapped at > >> something above 4G with a 32-bit EFI and whether that could work ok. > >> Hmm. > >> > >> Lemme add Ard and mfleming for insight here. > >> > > > >-ENOCONTEXT, but let me try in any case: > > > >linux/efi.h has > > > >typedef struct { > > efi_guid_t guid; > > u32 table; > >} efi_config_table_32_t; > > > >so if we end up with more than 32 bits set in table, there is > >something seriously wrong. > > > >The size of efi_config_table_32_t deviates from efi_config_table_64_t, > >so you will have to ensure that you are using the correct stride when > >iterating over config_tables. > > Here I use signature to judge it. > If the signature is EFI64_LOADER_SIGNATURE, I will use efi_config_table_64_t, > if the signature is EFI32_LOADER_SIGNATURE, I will use efi_config_table_32_t. > But the efi32 whose signature is EFI32_LOADER_SIGNATURE points to a > address above 4G, I am not sure whether this is normal and works well. > This is impossible. The 'table' member of efi_config_table_32_t is only 32 bits wide, so how can it contain an address over 4 GB ?