linux-kernel - Re: [RFC PATCH v3 3/4] arm64: Handle miscellaneous functions in .text and .init.text

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: <20210506141211.GE4642@sirena.org.uk>
Date:   Thu, 6 May 2021 15:12:11 +0100
From:   Mark Brown <broonie@...nel.org>
To:     madvenka@...ux.microsoft.com
Cc:     jpoimboe@...hat.com, mark.rutland@....com, jthierry@...hat.com,
        catalin.marinas@....com, will@...nel.org, jmorris@...ei.org,
        pasha.tatashin@...een.com, linux-arm-kernel@...ts.infradead.org,
        live-patching@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v3 3/4] arm64: Handle miscellaneous functions in
 .text and .init.text

On Mon, May 03, 2021 at 12:36:14PM -0500, madvenka@...ux.microsoft.com wrote:

> There are some SYM_CODE functions that are currently in ".text" or
> ".init.text" sections. Some of these are functions that the unwinder
> does not care about as they are not "interesting" to livepatch. These
> will remain in their current sections. The rest I have moved into a
> new section called ".code.text".

I was thinking it'd be good to do this by modifying SYM_CODE_START() to
emit the section, that way nobody can forget to put any SYM_CODE into a
special section.  That does mean we'd have to first introduce a new
variant for specifying a section that lets us override things that need
to be in some specific section and convert everything that's in a
special section over to that first which is a bit annoying but feels
like it's worth it for the robustness.  It'd also put some of the don't
cares into .code.text but so long as they are actually don't cares that
should be fine!

> Don't care functions
> ====================

We also have a bunch of things like __cpu_soft_restart which don't seem
to be called out here but need to be in .idmap.text.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)