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 8152CC54EBC for ; Sat, 7 Jan 2023 16:22:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230298AbjAGQWF (ORCPT ); Sat, 7 Jan 2023 11:22:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229695AbjAGQWE (ORCPT ); Sat, 7 Jan 2023 11:22:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C44895F918; Sat, 7 Jan 2023 08:22:03 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 358F160AFF; Sat, 7 Jan 2023 16:22:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8DBFEC433D2; Sat, 7 Jan 2023 16:22:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673108522; bh=Sc5iPDa0U8NcuBkO0eUQDplNpDRaMMwiLbcndIZn8sE=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=E9As+DcVM3BDmBJYyMGTdxjwBVCmO9vnwAJgVf/SiyMIoNmN8tIMu+ZS9ceujIdYn QdPrCsmat1F13jcUDeyZ3/AJUeB+X6Yr9vypO8npFMmQRmfsy0SaX1U4QAMKA8jKQi xPAVg0UzK62DcN5Yiib2I5umPOizEQ0FUMJWsHLi1b/Zaou7Xe8b7eXgpJmqU1wns9 7MQhRSI+O0zEROC8GP5D8UqcJxijkSYyer/SDtW50VCsyS3qhU9KQupfFKhzsUoGKk 93wHm9zZ9Oyw7W8VWildrb8jE69UJhdNscXmRkRRml0LnYUhiuq/Ia79PgWYDYvF0P OySqe2MJ6spWA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 3989C5C09F1; Sat, 7 Jan 2023 08:22:02 -0800 (PST) Date: Sat, 7 Jan 2023 08:22:02 -0800 From: "Paul E. McKenney" To: Masami Hiramatsu 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: <20230107162202.GA4028633@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20230105005838.GA1772817@paulmck-ThinkPad-P17-Gen-1> <20230108002215.c18df95b19acdd3207b379fa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230108002215.c18df95b19acdd3207b379fa@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org 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. > 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? 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 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.