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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS 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 777D8C433E1 for ; Wed, 15 Jul 2020 22:38:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49D1F206F4 for ; Wed, 15 Jul 2020 22:38:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594852728; bh=G2gD9bUnjwJBZJyX27Mq12AcTz2bMWaZiUgRCKKBLt4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=RgIeBgQWJUOxG0b8NORd6wimJWHR4KF3OUWyBd8+BdxsgbQaA5kpLOhc1W6tRx0dp 5Q4KQG3QzFDn8FtJnbsxmlf00a5lxwKmFVmVCvtlKnhDCW3NufsgvgMUZAwcOI+p39 djXYKW0MICyWaUEHLkxot+zr5spQ23RXZ1EzH0Zo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726765AbgGOWir (ORCPT ); Wed, 15 Jul 2020 18:38:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:40584 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726660AbgGOWir (ORCPT ); Wed, 15 Jul 2020 18:38:47 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (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 0528820658; Wed, 15 Jul 2020 22:38:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594852727; bh=G2gD9bUnjwJBZJyX27Mq12AcTz2bMWaZiUgRCKKBLt4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pjxL2sNcYqpTR1P1s21ZgPk/jqfBzJ15+1Xmo4G30kbij2t8+GiHbbSxUQDS2h4Tp HufsuBDEFIq3PVZ08CztEE8++ZXpom42m6rsjTEoAGnNitai6wN+DESGlKVXudu140 U3iQGVrWqYrjW7IfqSULqoic05Wbxrfioyjmv2M0= Date: Thu, 16 Jul 2020 07:38:43 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: Alistair Delva , linux-doc@vger.kernel.org, LKML Subject: Re: [PATCH 0/3] bootconfig: Add value override operator Message-Id: <20200716073843.e7b1921aae962da9e5714fe0@kernel.org> In-Reply-To: <20200715164504.3400efc5@oasis.local.home> References: <159482882056.126704.15508672095852220119.stgit@devnote2> <20200715164504.3400efc5@oasis.local.home> X-Mailer: Sylpheed 3.7.0 (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 Wed, 15 Jul 2020 16:45:04 -0400 Steven Rostedt wrote: > On Thu, 16 Jul 2020 01:00:21 +0900 > Masami Hiramatsu wrote: > > > With this change, if the bootloader wants to change some value > > in the default bootconfig, it doesn't need to parse the existing > > bootconfig, but it can just append the new configs at the tail > > of the bootconfig and update the footer (size, checksum and magic > > word). > > I wonder if we should support multiple bootconfigs instead of updating > the size/checksum/magic? > > 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. Thank you, -- Masami Hiramatsu