linux-kernel - Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323 regulator

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20160127144105.GQ6042@sirena.org.uk>
Date:	Wed, 27 Jan 2016 14:41:05 +0000
From:	Mark Brown <broonie@...nel.org>
To:	John Crispin <blogic@...nwrt.org>
Cc:	Liam Girdwood <lgirdwood@...il.com>,
	Chen Zhong <chen.zhong@...iatek.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323
 regulator

On Wed, Jan 27, 2016 at 01:00:59PM +0100, John Crispin wrote:

> +		/* Constrain board-specific capabilities according to what
> +		 * this driver and the chip itself can actually do.
> +		 */
> +		c = rdev->constraints;
> +		c->valid_modes_mask |= REGULATOR_MODE_NORMAL |
> +				       REGULATOR_MODE_STANDBY;
> +		c->valid_ops_mask |= REGULATOR_CHANGE_MODE;

No, drivers should *never* enable things that weren't explictly enabled
by the machine constraints.  This misses the whole point of having
constraints.  They are there so that the system integrator can enable
the functionality that is safe on a given board.  

The comment is also inaccurate, it claims it's imposing constraints but
in fact it's adding additional permissions.

Download attachment "signature.asc" of type "application/pgp-signature" (474 bytes)