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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE251C4332F for ; Mon, 14 Mar 2022 08:05:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237470AbiCNIG0 (ORCPT ); Mon, 14 Mar 2022 04:06:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239328AbiCNIFG (ORCPT ); Mon, 14 Mar 2022 04:05:06 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 859CA338; Mon, 14 Mar 2022 01:03:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id EFA4FCE10A8; Mon, 14 Mar 2022 08:03:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20D6CC340EE; Mon, 14 Mar 2022 08:03:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1647245016; bh=PLyOXRyp/joleXlKUaTg+BlpTSHFV9oVS+l3FdSBbwo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=CoNJ/MP0igatf0tWuoiMqW6Sx0dzD74K0reoXCLyI5WFnqrNwB5zJdwzzcXHBIYVi aIOCKgf8PevIfE98O8McZ5V88s0BjEHAreCAkiWXoutB1x+L0PVStbHDE7ej7Rm5t/ FWCZ+lkC8wH7+PXs8frjFvPP84vAW9zfV6b0SWg13DsZ/0yeHiT54sud/7kjNZCB9+ 0mz/Djy/Bk0iHb4SYdXHoPTYRRfcHv7Op4VzYYEBq8S5tI5oFpFe3x3pcUia/liMNJ Rtywa7DcpdxWL3b5Or5cf0M2W14gUowW+jzKhcvlkdpm5uSLXNidTdDm374mmYDvtm aV3NQv3am6byg== Date: Mon, 14 Mar 2022 17:03:33 +0900 From: Masami Hiramatsu To: Randy Dunlap Cc: Steven Rostedt , Padmanabha Srinivasaiah , LKML , Jonathan Corbet , linux-doc@vger.kernel.org Subject: Re: [PATCH v2 3/3] docs: bootconfig: Add how to embed the bootconfig into kernel Message-Id: <20220314170333.0311c13a654c63d7ebe68e1f@kernel.org> In-Reply-To: <8ad1fb98-3141-1e57-b627-0c8184fef955@infradead.org> References: <164722283333.689258.144495814460576707.stgit@devnote2> <164722286373.689258.9817790360544187508.stgit@devnote2> <8ad1fb98-3141-1e57-b627-0c8184fef955@infradead.org> 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 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Sun, 13 Mar 2022 19:03:20 -0700 Randy Dunlap wrote: > > > On 3/13/22 18:54, Masami Hiramatsu wrote: > > Add a description how to embed the bootconfig file into kernel. > > > > Signed-off-by: Masami Hiramatsu > > --- > > Changes in v2: > > - Corrected the text accoding to Randy's suggestion. > > - Do not reccomend to use relative path for CONFIG_EMBED_BOOT_CONFIG_FILE. > > --- > > Documentation/admin-guide/bootconfig.rst | 30 +++++++++++++++++++++++++++--- > > 1 file changed, 27 insertions(+), 3 deletions(-) > > > > diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst > > index a1860fc0ca88..1af1a172fdd4 100644 > > --- a/Documentation/admin-guide/bootconfig.rst > > +++ b/Documentation/admin-guide/bootconfig.rst > > @@ -158,9 +158,15 @@ Each key-value pair is shown in each line with following style:: > > Boot Kernel With a Boot Config > > ============================== > > > > -Since the boot configuration file is loaded with initrd, it will be added > > -to the end of the initrd (initramfs) image file with padding, size, > > -checksum and 12-byte magic word as below. > > +There are two options to boot the kernel with bootconfig: attaching the > > +bootconfig to the initrd image or embedding it in the kernel itself. > > + > > +Attaching a Boot Config to Initrd > > +--------------------------------- > > + > > +Since the boot configuration file is loaded with initrd by default, > > +it will be added to the end of the initrd (initramfs) image file with > > +padding, size, checksum and 12-byte magic word as below. > > > > [initrd][bootconfig][padding][size(le32)][checksum(le32)][#BOOTCONFIG\n] > > > > @@ -196,6 +202,24 @@ To remove the config from the image, you can use -d option as below:: > > Then add "bootconfig" on the normal kernel command line to tell the > > kernel to look for the bootconfig at the end of the initrd file. > > > > +Embedding a Boot Config into Kernel > > +----------------------------------- > > + > > +If you can not use initrd, you can also embed the bootconfig file in the > > +kernel by Kconfig options. In this case, you need to recompile the kernel > > +with the following configs:: > > + > > + COFNIG_EMBED_BOOT_CONFIG=y > > CONFIG_ Oops, it's a typo... > > > + CONFIG_EMBED_BOOT_CONFIG_FILE="/PATH/TO/BOOTCONFIG/FILE" > > + > > +``CONFIG_EMBED_BOOT_CONFIG_FILE`` requires a correct absolute path to > > +the bootconfig file. The kernel will embed it as the default bootconfig. > > + > > +Just as when attaching the bootconfig to the initrd, you need ``bootconfig`` > > +option to the kernel command line to enable the embedded bootconfig. > > on the OK. Thank you! > > preferably. > > > + > > +Note that even if you set this option, you can override the embedded > > +bootconfig by another bootconfig which attached to the initrd. > > > > Kernel parameters via Boot Config > > ================================= > > > > thanks. > -- > ~Randy -- Masami Hiramatsu