From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: 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>,
Bill Wendling <morbo@google.com>,
linuxppc-dev@lists.ozlabs.org, Daniel Axtens <dja@axtens.net>
Subject: Re: [PATCH] ppc: add "-z notext" flag to disable diagnostic
Date: Sat, 14 Aug 2021 06:01:50 -0500 [thread overview]
Message-ID: <20210814110150.GB1583@gate.crashing.org> (raw)
In-Reply-To: <CAKwvOd=rN9s5YBtt-AMnaqXhYCsAT=6yp29_oomRvTaev6Q6zw@mail.gmail.com>
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
WARNING: multiple messages have this Message-ID (diff)
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
Date: Sat, 14 Aug 2021 06:01:50 -0500 [thread overview]
Message-ID: <20210814110150.GB1583@gate.crashing.org> (raw)
In-Reply-To: <CAKwvOd=rN9s5YBtt-AMnaqXhYCsAT=6yp29_oomRvTaev6Q6zw@mail.gmail.com>
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
next prev parent reply other threads:[~2021-08-14 11:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 20:49 [PATCH] ppc: add "-z notext" flag to disable diagnostic Bill Wendling
2021-08-12 20:53 ` Nick Desaulniers
2021-08-12 20:53 ` Nick Desaulniers
2021-08-13 14:13 ` Daniel Axtens
2021-08-13 18:24 ` Bill Wendling
2021-08-13 18:24 ` Bill Wendling
2021-08-13 18:59 ` Nick Desaulniers
2021-08-13 18:59 ` Nick Desaulniers
2021-08-14 11:01 ` Segher Boessenkool [this message]
2021-08-14 11:01 ` Segher Boessenkool
2021-08-14 11:59 ` Michael Ellerman
2021-08-14 11:59 ` Michael Ellerman
2021-08-13 20:05 ` Fangrui Song
2021-08-13 20:05 ` Fangrui Song
2021-08-14 12:58 ` Segher Boessenkool
2021-08-14 12:58 ` Segher Boessenkool
2021-08-14 19:34 ` Fāng-ruì Sòng
2021-08-14 19:34 ` Fāng-ruì Sòng
2021-08-27 14:40 ` Segher Boessenkool
2021-08-27 14:40 ` Segher Boessenkool
2021-08-13 20:05 ` [PATCH v2] " Bill Wendling
2021-08-13 20:05 ` Bill Wendling
2021-08-27 13:15 ` Michael Ellerman
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