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=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 9BEB4C43381 for ; Sun, 10 Mar 2019 06:18:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B2E92086A for ; Sun, 10 Mar 2019 06:18:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552198728; bh=z5QReKz+CxjyUuLwQnpNvSIDkA9ajgLKi1EzjlWsxxg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=0j8o0msrJ3aYO4MiJ5KSuatl3fiZVSPScIElhpO8fNtKNQTjFjFjCioiaq6Wkn0wU zuK8knqp+3PxgZH4pSy7GzfzYxeoijlpFfwR+hSa1lG2yYpvDZMZPtj6sBHvTrATeb 6jINdMEnJvSM6I1edgtQyvFBAr25oIjMvC1lFQg0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725828AbfCJGSo (ORCPT ); Sun, 10 Mar 2019 01:18:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:40890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725777AbfCJGSn (ORCPT ); Sun, 10 Mar 2019 01:18:43 -0500 Received: from localhost (unknown [89.248.140.16]) (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 555F2207E0; Sun, 10 Mar 2019 06:18:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552198722; bh=z5QReKz+CxjyUuLwQnpNvSIDkA9ajgLKi1EzjlWsxxg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EPIHBbseocxGIHZNuEzW7+43ssvUK4fOO3qqRn4H2Dqv5f6IiaRBIrzUlEdZ/6c5k uriBlKuUBTDqIle36S5cnwiU6pzSKisFOkeIy470EoUdSn0dyBuhnqXWWTCZl+wta4 bOsqt+YbFdDnemdI/lx2KwZOAzspW1QPqzIblSkk= Date: Sun, 10 Mar 2019 07:18:40 +0100 From: Greg Kroah-Hartman To: hpa@zytor.com Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Pitam Mitra , "Kirill A. Shutemov" , Thomas Gleixner , Bockjoo Kim , bp@alien8.de Subject: Re: [PATCH 5.0 30/46] x86/boot/compressed/64: Do not read legacy ROM on EFI system Message-ID: <20190310061840.GA21641@kroah.com> References: <20190308124902.257040783@linuxfoundation.org> <20190308124904.216497374@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 09, 2019 at 10:10:19PM -0800, hpa@zytor.com wrote: > On March 8, 2019 4:50:03 AM PST, Greg Kroah-Hartman wrote: > >5.0-stable review patch. If anyone has any objections, please let me > >know. > > > >------------------ > > > >From: Kirill A. Shutemov > > > >commit 6f913de3231e1d70a871135b38219da7810df218 upstream. > > > >EFI systems do not necessarily provide a legacy ROM. If the ROM is > >missing > >the memory is not mapped at all. > > > >Trying to dereference values in the legacy ROM area leads to a crash on > >Macbook Pro. > > > >Only look for values in the legacy ROM area for non-EFI system. > > > >Fixes: 3548e131ec6a ("x86/boot/compressed/64: Find a place for 32-bit > >trampoline") > >Reported-by: Pitam Mitra > >Signed-off-by: Kirill A. Shutemov > >Signed-off-by: Thomas Gleixner > >Tested-by: Bockjoo Kim > >Cc: bp@alien8.de > >Cc: hpa@zytor.com > >Cc: stable@vger.kernel.org > >Link: > >https://lkml.kernel.org/r/20190219075224.35058-1-kirill.shutemov@linux.intel.com > >Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202351 > >Signed-off-by: Greg Kroah-Hartman > > > >--- > > arch/x86/boot/compressed/pgtable_64.c | 19 ++++++++++++++++--- > > 1 file changed, 16 insertions(+), 3 deletions(-) > > > >--- a/arch/x86/boot/compressed/pgtable_64.c > >+++ b/arch/x86/boot/compressed/pgtable_64.c > >@@ -1,5 +1,7 @@ > >+#include > > #include > > #include > >+#include > > #include "pgtable.h" > > #include "../string.h" > > > >@@ -37,9 +39,10 @@ int cmdline_find_option_bool(const char > > > > static unsigned long find_trampoline_placement(void) > > { > >- unsigned long bios_start, ebda_start; > >+ unsigned long bios_start = 0, ebda_start = 0; > > unsigned long trampoline_start; > > struct boot_e820_entry *entry; > >+ char *signature; > > int i; > > > > /* > >@@ -47,8 +50,18 @@ static unsigned long find_trampoline_pla > > * This code is based on reserve_bios_regions(). > > */ > > > >- ebda_start = *(unsigned short *)0x40e << 4; > >- bios_start = *(unsigned short *)0x413 << 10; > >+ /* > >+ * EFI systems may not provide legacy ROM. The memory may not be > >mapped > >+ * at all. > >+ * > >+ * Only look for values in the legacy ROM for non-EFI system. > >+ */ > >+ signature = (char *)&boot_params->efi_info.efi_loader_signature; > >+ if (strncmp(signature, EFI32_LOADER_SIGNATURE, 4) && > >+ strncmp(signature, EFI64_LOADER_SIGNATURE, 4)) { > >+ ebda_start = *(unsigned short *)0x40e << 4; > >+ bios_start = *(unsigned short *)0x413 << 10; > >+ } > > > > if (bios_start < BIOS_START_MIN || bios_start > BIOS_START_MAX) > > bios_start = BIOS_START_MAX; > > Only one objection: the explanation is nonsensical. Heh, take it up with the original submitter, I don't change the changelog text after it hits Linus's tree :) greg k-h