linux-kernel - Re: [PATCH] ppc: add "-z notext" flag to disable diagnostic

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: <20210814110150.GB1583@gate.crashing.org>
Date:   Sat, 14 Aug 2021 06:01:50 -0500
From:   Segher Boessenkool <segher@...nel.crashing.org>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Bill Wendling <morbo@...gle.com>,
        Fangrui Song <maskray@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Nathan Chancellor <nathan@...nel.org>,
        clang-built-linux <clang-built-linux@...glegroups.com>,
        Paul Mackerras <paulus@...ba.org>,
        linuxppc-dev@...ts.ozlabs.org, Daniel Axtens <dja@...ens.net>
Subject: Re: [PATCH] ppc: add "-z notext" flag to disable diagnostic

On Fri, Aug 13, 2021 at 11:59:21AM -0700, Nick Desaulniers wrote:
> Or we can dig through why there are relocations in read only sections,
> fix those, then enable `-z text` for all linkers.  My recommendation
> would be get the thing building, then go digging time permitting.

It is not always a bug.  You can get much more efficient code if you
have text relocations than if you don't.  This "read-only" memory is
perfectly writable until after relocation, a la relro.

But you no doubt will find some non-optimalities (or even straight out
bugs) if you build with -ztext sometimes :-)


Segher