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 46555C54EBD for ; Mon, 9 Jan 2023 23:56:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235432AbjAIX4u (ORCPT ); Mon, 9 Jan 2023 18:56:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231358AbjAIX4p (ORCPT ); Mon, 9 Jan 2023 18:56:45 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1788F63BF; Mon, 9 Jan 2023 15:56:44 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id BE6DBB810B6; Mon, 9 Jan 2023 23:56:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31414C433F0; Mon, 9 Jan 2023 23:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673308601; bh=kGARkBvg/xZwK6CWO/t5enuGZ6gCSiDIREKt17POl5E=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Gxa59t26s3y4iWedgV4KymKF8cdE5/UHHJSgpvmQJs7o7RIpfxahlrtLPXveCOj0x /FKdziCBpOgKUNYi4/4Sy+9wDYnzO5ORH9zzgXz70Yg/WfqsPzBebtB5/GIaUx5wlH rfkQ2WXIZLYv1jlmYvtAbSorXGjgXxEeGFG1KDbq6mHfHCZThXzNgiuJzpOEG4Y4II GNFdLOTdFsLCCKx8FhEwhdcArFpjKQCOJlpxAXEOJe5M2FauXL25ZILcDtaF4aX1EI c27LmrUzd3cBtpLzj4MoWRHGwSc9nahdrDvBhNV+OM47I1POqDGgzxtjc1G5l8Jong Zp9GLxcQ8pe9Q== Date: Tue, 10 Jan 2023 08:56:36 +0900 From: Masami Hiramatsu (Google) To: paulmck@kernel.org Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, corbet@lwn.net, akpm@linux-foundation.org, ndesaulniers@google.com, vbabka@suse.cz, hannes@cmpxchg.org, joel@joelfernandes.org, quic_neeraju@quicinc.com, urezki@gmail.com Subject: Re: [PATCH RFC bootconfig] Allow forcing unconditional bootconfig processing Message-Id: <20230110085636.5d679f98c5b6914ecf19e724@kernel.org> In-Reply-To: <20230109042501.GF4028633@paulmck-ThinkPad-P17-Gen-1> References: <20230105005838.GA1772817@paulmck-ThinkPad-P17-Gen-1> <20230108002215.c18df95b19acdd3207b379fa@kernel.org> <20230107162202.GA4028633@paulmck-ThinkPad-P17-Gen-1> <20230108150425.426f2861e9db1152fa84508f@kernel.org> <20230109042501.GF4028633@paulmck-ThinkPad-P17-Gen-1> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; 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-kernel@vger.kernel.org On Sun, 8 Jan 2023 20:25:01 -0800 "Paul E. McKenney" wrote: > On Sun, Jan 08, 2023 at 03:04:25PM +0900, Masami Hiramatsu wrote: > > On Sat, 7 Jan 2023 08:22:02 -0800 > > "Paul E. McKenney" wrote: > > > > > On Sun, Jan 08, 2023 at 12:22:15AM +0900, Masami Hiramatsu wrote: > > > > On Wed, 4 Jan 2023 16:58:38 -0800 > > > > "Paul E. McKenney" wrote: > > > > > > > > > The BOOT_CONFIG family of Kconfig options allows a bootconfig file > > > > > containing kernel boot parameters to be embedded into an initrd or into > > > > > the kernel itself. This can be extremely useful when deploying kernels > > > > > in cases where some of the boot parameters depend on the kernel version > > > > > rather than on the server hardware, firmware, or workload. > > > > > > > > > > Unfortunately, the "bootconfig" kernel parameter must be specified in > > > > > order to cause the kernel to look for the embedded bootconfig file, > > > > > and it clearly does not help to embed this "bootconfig" kernel parameter > > > > > into that file. > > > > > > > > > > Therefore, provide a new BOOT_CONFIG_FORCE Kconfig option that causes the > > > > > kernel to act as if the "bootconfig" kernel parameter had been specified. > > > > > In other words, kernels built with CONFIG_BOOT_CONFIG_FORCE=y will look > > > > > for the embedded bootconfig file even when the "bootconfig" kernel > > > > > parameter is omitted. This permits kernel-version-dependent kernel > > > > > boot parameters to be embedded into the kernel image without the need to > > > > > (for example) update large numbers of boot loaders. > > > > > > > > I like this because this is a simple solution. We have another option > > > > to specify "bootconfig" in CONFIG_CMDLINE, but it can be overwritten by > > > > bootloader. Thus, it is better to have this option so that user can > > > > always enable bootconfig. > > > > > > Glad you like it! > > > > > > In addition, if the help text is accurate, another shortcoming of > > > CONFIG_CMDLINE is that its semantics vary from one architecture to > > > another. Some have CONFIG_CMDLINE override the boot-loader supplied > > > parameters, and others differ in the order in which the parameters > > > are processed. > > > > Yes, that differences confuse us... > > I am glad that it is not just me. ;-) > > I will add words to that effect to the commit log. > > > > > Acked-by: Masami Hiramatsu (Google) > > > > > > Thank you! > > > > > > > BTW, maybe CONFIG_BOOT_CONFIG_EMBED is better to select this. > > > > (or at least recommend to enable this) > > > > > > Like this? > > > > Yes! Thanks. > > > > > > > > Thanx, Paul > > > > > > ------------------------------------------------------------------------ > > > > > > commit d09a1505c51a70da38b34ac38062977299aef742 > > > Author: Paul E. McKenney > > > Date: Sat Jan 7 08:09:22 2023 -0800 > > > > > > bootconfig: Default BOOT_CONFIG_FORCE to y if BOOT_CONFIG_EMBED > > > > > > When a kernel is built with CONFIG_BOOT_CONFIG_EMBED=y, the intention > > > will normally be to unconditionally provide the specified kernel-boot > > > arguments to the kernel, as opposed to requiring a separately provided > > > bootconfig parameter. Therefore, make the BOOT_CONFIG_FORCE Kconfig > > > option default to y in kernels built with CONFIG_BOOT_CONFIG_EMBED=y. > > > > > > The old semantics may be obtained by manually overriding this default. > > > > > > Suggested-by: Masami Hiramatsu > > > Signed-off-by: Paul E. McKenney > > > > Acked-by: Masami Hiramatsu (Google) > > Applied, thank you! > > Thanx, Paul Paul, just for confirmation, have you picked these patches on your tree? Thank you, > > > Thank you! > > > > > > > > diff --git a/init/Kconfig b/init/Kconfig > > > index 0fb19fa0edba9..97a0f14d9020d 100644 > > > --- a/init/Kconfig > > > +++ b/init/Kconfig > > > @@ -1379,6 +1379,7 @@ config BOOT_CONFIG > > > config BOOT_CONFIG_FORCE > > > bool "Force unconditional bootconfig processing" > > > depends on BOOT_CONFIG > > > + default y if BOOT_CONFIG_EMBED > > > help > > > With this Kconfig option set, BOOT_CONFIG processing is carried > > > out even when the "bootconfig" kernel-boot parameter is omitted. > > > > > > -- > > Masami Hiramatsu (Google) -- Masami Hiramatsu (Google)