linux-kernel - Re: [PATCH] Disable non-ABI-compliant optimisations for live patching

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]

Date:	Mon, 27 Jun 2016 08:59:49 +0200
From:	Torsten Duwe <duwe@....de>
To:	Pavel Machek <pavel@....cz>
Cc:	Jiri Kosina <jikos@...nel.org>, Miroslav Benes <mbenes@...e.cz>,
	Josh Poimboeuf <jpoimboe@...hat.com>, matz@...e.de,
	live-patching@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Disable non-ABI-compliant optimisations for live patching

On Mon, Jun 27, 2016 at 12:39:56AM +0200, Pavel Machek wrote:

> Would it be possible to document which kind of guarantees live
> patching needs from compiler?

Sure, here you go, all required guarantees:

Stick to the ABI.

> I always assumed that whoever is preparing the patch does manual
> investigation to see what needs to be changed and how, but apparantly
> that's not the case, so documentation would be good.

See above for the documentation. Imagine each architecture had a whole
hand-optimised assembler kernel. That would give some performance
improvement, right? Same issue here, only much smaller. It's ultimate
performance vs. maintainability.

HTH,
	Torsten