linux-kernel - Re: [PATCH v7 11/11] arm64: defconfig: Enable OF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <Z6n3JLOn-PrSt3Pa@apocalypse>
Date: Mon, 10 Feb 2025 13:55:00 +0100
From: Andrea della Porta <andrea.porta@...e.com>
To: Stefan Wahren <wahrenst@....net>
Cc: Andrea della Porta <andrea.porta@...e.com>,
	Michael Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczynski <kw@...ux.com>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>, Bartosz Golaszewski <brgl@...ev.pl>,
	Derek Kiernan <derek.kiernan@....com>,
	Dragan Cvetic <dragan.cvetic@....com>,
	Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Saravana Kannan <saravanak@...gle.com>, linux-clk@...r.kernel.org,
	devicetree@...r.kernel.org, linux-rpi-kernel@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, linux-gpio@...r.kernel.org,
	Masahiro Yamada <masahiroy@...nel.org>,
	Herve Codina <herve.codina@...tlin.com>,
	Luca Ceresoli <luca.ceresoli@...tlin.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
	Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH v7 11/11] arm64: defconfig: Enable OF_OVERLAY option

Hi Stefan,

On 14:42 Sat 08 Feb     , Stefan Wahren wrote:
> Hi Andrea,
> 
> Am 07.02.25 um 22:31 schrieb Andrea della Porta:
> > The RP1 driver uses the infrastructure enabled by OF_OVERLAY config
> > option. Enable that option in defconfig in order to produce a kernel
> > usable on RaspberryPi5 avoiding to enable it separately.
> > 
> > Signed-off-by: Andrea della Porta <andrea.porta@...e.com>
> > ---
> > This patch is *OPTIONAL* since I'm not sure if OF_OVERLAY is a desirable
> > feature to have enabled by default. It would be advisable to have it included
> > so that 'make defconfig' can produce a kernel config that will work out
> > of the box on Rpi5, otherwise OF_OVERLAY has to be enabled separately.
> I think this isn't a good approach to convince the arm64 maintainer.
> This change is not really optional for the Raspberry Pi 5 and possible
> users/testers/CI rely on a working default configuration.
> 
> So my first suggestion would be to provide a scripts/bloat-o-meter
> output (before/after). Based on this the maintainer can better decided.

I agree with you. IIUC what you are proposing, the following metrics should
help to decide. The defconfig kernel with CONFIG_OF_OVERLAY=y added (wrt to
the defconfig one without that set) has:

- same uncompressed kernel image size (due to ELF section alignment I guess)

- ~7Kb bigger Image.gz

- 3 new modules (all related to RP1, i.e.: clk-rp1, pinctrl-rp1 and rp1-pci)

- 27 added symbols, of which 5 exported
 
hoping this is enough to gather a rough idea of the impact.

> 
> In case this change is still rejected, we still have the option of
> something like this [1]

I'm ready to go down this way should the previous numbers not be convincing
enough.

Many thanks,
Andrea

> 
> Best regards
> 
> [1] -
> https://patchwork.kernel.org/project/linux-kbuild/patch/20200203184820.4433-3-nsaenzjulienne@suse.de/