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 369A5C54EBC for ; Sun, 8 Jan 2023 06:04:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231252AbjAHGEg (ORCPT ); Sun, 8 Jan 2023 01:04:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbjAHGEd (ORCPT ); Sun, 8 Jan 2023 01:04:33 -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 7C77018E1A; Sat, 7 Jan 2023 22:04:31 -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 058E760BEA; Sun, 8 Jan 2023 06:04:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE5B3C433EF; Sun, 8 Jan 2023 06:04:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673157870; bh=sxLgw656KnRhuwO4+fEm20uaNlzK9/wJ1eViWMHL/MA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=VG2FzlZrQ0OylbElYkju0RS8ASh09uSSC7uLeSmk8vsATiLviUHQENieO5eibnks9 71YMNRswTO9P6iXKurRoDf2dE+3s7sJh+JbOpup3uzN0g88ZUoqUKJbuzBjPyRta/6 n1yRH8f6ZkASgF9E3AjVita7rB/ODS+OPzpZ/47ER9sMuRZxyYPGilbVOkBizpWddz V7DjefuZA0JgdRhx8HB8tqnPK68XGcC6m25vSoQI6ttF1YxzmS0zJa8sXQ4qVrRH92 s13D5of+gnIgK11XvGluW1lKfENXinkdwzm+0AhDRRy9CNxOxP4349nNmd13QCBs8Q DTyEnwImx0PIA== Date: Sun, 8 Jan 2023 15:04:25 +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: <20230108150425.426f2861e9db1152fa84508f@kernel.org> In-Reply-To: <20230107162202.GA4028633@paulmck-ThinkPad-P17-Gen-1> References: <20230105005838.GA1772817@paulmck-ThinkPad-P17-Gen-1> <20230108002215.c18df95b19acdd3207b379fa@kernel.org> <20230107162202.GA4028633@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 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... > > > 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) 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)