Re: [PATCH 1/4] add generic builtin command line

From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Pratyush Brahma <quic_pbrahma@quicinc.com>,
	"danielwa@cisco.com" <danielwa@cisco.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	"dwalker@fifo99.com" <dwalker@fifo99.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"maksym.kokhan@globallogic.com" <maksym.kokhan@globallogic.com>,
	"mpe@ellerman.id.au" <mpe@ellerman.id.au>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"tomas.mudrunka@gmail.com" <tomas.mudrunka@gmail.com>,
	"xe-linux-external@cisco.com" <xe-linux-external@cisco.com>,
	Pavan Kondeti <quic_pkondeti@quicinc.com>,
	"quic_guptap@quicinc.com" <quic_guptap@quicinc.com>,
	"quic_vjitta@quicinc.com" <quic_vjitta@quicinc.com>
Subject: Re: [PATCH 1/4] add generic builtin command line
Date: Wed, 8 Nov 2023 11:33:37 +0000	[thread overview]
Message-ID: <3d127abf-abdc-02e3-7c8b-a39b901ea641@csgroup.eu> (raw)
In-Reply-To: <4c420081-fe57-d036-ded7-2899c13738ee@quicinc.com>

Hi Pratyush,

Le 17/10/2023 à 12:40, Pratyush Brahma a écrit :
> Hi Daniel
> 
> We have a usecase which requires this patch necessarily. For android
> usecases, we have two different build variants
> differentiated by defconfigs - production and debug. However, we only
> have a single dts for both these variants.
> 
> 
> We want to enable certain features like page owner and slub debug which
> require cmdline params in addition to
> their respective configs to be enabled. Enabling page_owner and
> slub_debug options in dts file enables it for both
> production and debug variants. These features have significant memory
> overhead which are undesirable for
> our production environment. However, these are necessary for debug
> environment to enable internal testing and debug.
> Currently, android uses out-of-tree configs like CONFIG_CMDLINE_EXTEND
> to do so in gki_defconfig [1].
> One option is to use CMDLINE_FORCE option which would enable these
> cmdline params but this disables the bootloader to add
> any additional cmdline params which may be necessary.
> 
> 
> For such a usecase, the CONFIG_CMDLINE_PREPEND seems to be quite useful
> as it would help to stitch bootloader
> and the desired build variant's configs together. Can you please help to
> merge this patch?

As far as I remember, Daniel's proposal had some weaknesses that were 
never addressed. At that time I proposed an alternative series that was 
addressing most weaknesses, and my series was considered more mature 
that Daniel's one by several maintainers. But I never got enough 
feedback on it in order to finalise and merge it.

Could you have a look at it and tell if it fits your need ? See 
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?state=*&series=237158

If it does, I can then rebase it on latest kernel and restart 
discussions in order to get it merged.

Thanks
Christophe

> 
> 
> [1]
> https://android.googlesource.com/kernel/common/+/refs/heads/android14-6.1-lts/arch/arm64/configs/gki_defconfig#62
> 