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Date:   Sat, 14 Aug 2021 06:01:50 -0500
From:   Segher Boessenkool <segher@kernel.crashing.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Bill Wendling <morbo@google.com>,
        Fangrui Song <maskray@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>,
        Paul Mackerras <paulus@samba.org>,
        linuxppc-dev@lists.ozlabs.org, Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH] ppc: add "-z notext" flag to disable diagnostic
Message-ID: <20210814110150.GB1583@gate.crashing.org>
References: <20210812204951.1551782-1-morbo@google.com> <87sfzde8lk.fsf@linkitivity.dja.id.au> <CAGG=3QUz2LNgC8Hn6rU68ejjv4=J9Uidef0oH9A7=sKTs+vf7g@mail.gmail.com> <CAKwvOd=rN9s5YBtt-AMnaqXhYCsAT=6yp29_oomRvTaev6Q6zw@mail.gmail.com>
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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