linux-kernel - Re: [PATCH 00/46] gcc-LTO support for the kernel

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: <CAMj1kXFqNvs2OvLJLi2CQYtPe4_BquHQg55F8J=oO76N9wRT9g@mail.gmail.com>
Date:   Mon, 14 Nov 2022 12:56:43 +0100
From:   Ard Biesheuvel <ardb@...nel.org>
To:     "Jiri Slaby (SUSE)" <jirislaby@...nel.org>,
        Borislav Petkov <bp@...en8.de>
Cc:     linux-kernel@...r.kernel.org,
        Alexander Potapenko <glider@...gle.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Alexey Makhalov <amakhalov@...are.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Andrii Nakryiko <andrii@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ben Segall <bsegall@...gle.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Daniel Bristot de Oliveira <bristot@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Don Zickus <dzickus@...hat.com>, Hao Luo <haoluo@...gle.com>,
        "H . J . Lu" <hjl.tools@...il.com>,
        "H. Peter Anvin" <hpa@...or.com>, Huang Rui <ray.huang@....com>,
        Ingo Molnar <mingo@...hat.com>, Jan Hubicka <jh@...e.de>,
        Jason Baron <jbaron@...mai.com>,
        Jiri Kosina <jikos@...nel.org>, Jiri Olsa <jolsa@...nel.org>,
        Joe Lawrence <joe.lawrence@...hat.com>,
        John Fastabend <john.fastabend@...il.com>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Juergen Gross <jgross@...e.com>,
        Juri Lelli <juri.lelli@...hat.com>,
        KP Singh <kpsingh@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Martin KaFai Lau <martin.lau@...ux.dev>,
        Martin Liska <mliska@...e.cz>,
        Masahiro Yamada <masahiroy@...nel.org>,
        Mel Gorman <mgorman@...e.de>, Miguel Ojeda <ojeda@...nel.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Miroslav Benes <mbenes@...e.cz>,
        Namhyung Kim <namhyung@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@...m.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Petr Mladek <pmladek@...e.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Richard Biener <RGuenther@...e.com>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Song Liu <song@...nel.org>,
        Stanislav Fomichev <sdf@...gle.com>,
        Stefano Stabellini <sstabellini@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Valentin Schneider <vschneid@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        VMware PV-Drivers Reviewers <pv-drivers@...are.com>,
        Yonghong Song <yhs@...com>
Subject: Re: [PATCH 00/46] gcc-LTO support for the kernel

On Mon, 14 Nov 2022 at 12:44, Jiri Slaby (SUSE) <jirislaby@...nel.org> wrote:
>
> Hi,
>
> this is the first call for comments (and kbuild complaints) for this
> support of gcc (full) LTO in the kernel. Most of the patches come from
> Andi. Me and Martin rebased them to new kernels and fixed the to-use
> known issues. Also I updated most of the commit logs and reordered the
> patches to groups of patches with similar intent.
>
> The very first patch comes from Alexander and is pending on some x86
> queue already (I believe). I am attaching it only for completeness.
> Without that, the kernel does not boot (LTO reorders a lot).
>

You didn't cc me on that patch so I will reply here: I don't think
this is the right solution.
On x86, there is a lot of stuff injected into .head.text that simply
does not belong there, and getting rid of the __head annotation and
dropping __HEAD from the Xen pvh head.S file would be a much better
solution.