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References: <20221114114344.18650-1-jirislaby@kernel.org>
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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Mon, 14 Nov 2022 12:56:43 +0100
Message-ID: <CAMj1kXFqNvs2OvLJLi2CQYtPe4_BquHQg55F8J=oO76N9wRT9g@mail.gmail.com>
Subject: Re: [PATCH 00/46] gcc-LTO support for the kernel
To:     "Jiri Slaby (SUSE)" <jirislaby@kernel.org>,
        Borislav Petkov <bp@alien8.de>
Cc:     linux-kernel@vger.kernel.org,
        Alexander Potapenko <glider@google.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Alexei Starovoitov <ast@kernel.org>,
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        Andrey Konovalov <andreyknvl@gmail.com>,
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        Andrii Nakryiko <andrii@kernel.org>,
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        Daniel Borkmann <daniel@iogearbox.net>,
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On Mon, 14 Nov 2022 at 12:44, Jiri Slaby (SUSE) <jirislaby@kernel.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.