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=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 690D9C433DF for ; Thu, 16 Jul 2020 00:02:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D5E62071B for ; Thu, 16 Jul 2020 00:02:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726770AbgGPACP (ORCPT ); Wed, 15 Jul 2020 20:02:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:44404 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726479AbgGPACO (ORCPT ); Wed, 15 Jul 2020 20:02:14 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 23F9620714; Thu, 16 Jul 2020 00:02:14 +0000 (UTC) Date: Wed, 15 Jul 2020 20:02:12 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: Alistair Delva , linux-doc@vger.kernel.org, LKML Subject: Re: [PATCH 0/3] bootconfig: Add value override operator Message-ID: <20200715200212.0db61d5a@oasis.local.home> In-Reply-To: <20200716073843.e7b1921aae962da9e5714fe0@kernel.org> References: <159482882056.126704.15508672095852220119.stgit@devnote2> <20200715164504.3400efc5@oasis.local.home> <20200716073843.e7b1921aae962da9e5714fe0@kernel.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, 16 Jul 2020 07:38:43 +0900 Masami Hiramatsu wrote: > > So the end of the initrd would have: > > > > [data][size/checksum/magic][more-data][size/checksum/magic] > > > > > > And the kernel could do the following: > > > > 1. read the end of the initrd for bootconfig > > 2. If found parse the bootconfig data. > > 3. look at the content before the bootconfig > > 4. if another bootconfig exists, goto 2. > > > > Yeah, that is possible. But since the total size of the bootconfig > is limited to 32KB (this means data + 1st footer + more-data), > I would like to give a chance of sanity check to the bootloader. That's a limit of the size field, right? The bootloader (and all tools including the kernel) could check for multiple instances, and that would even increase the size of what can be added. As each section would be 32KB max size, but there's no limit to how many you have. All tools, bootconfig, the bootloader, and the kernel can perform the checksum. -- Steve