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Date:   Thu, 7 Mar 2019 12:27:12 +0100
From:   Alexey Gladkov <gladkov.alexey@gmail.com>
To:     Andi Kleen <ak@linux.intel.com>
Cc:     linux-kernel@vger.kernel.org,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Gleb Fotengauer-Malinovskiy <glebfm@altlinux.org>,
        "Dmitry V. Levin" <ldv@altlinux.org>
Subject: Re: [PATCH v1] moduleparam: Save information about built-in modules
 in separate file
Message-ID: <20190307112712.GA8455@Legion-PC.fortress>
References: <20190306165425.GD14017@MacBook-PC.fortress>
 <871s3jv97c.fsf@linux.intel.com>
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On Wed, Mar 06, 2019 at 04:07:03PM -0800, Andi Kleen wrote:
> Alexey Gladkov <gladkov.alexey@gmail.com> writes:
>=20
> > Problem:
> >
> > When a kernel module is compiled as a separate module, some important
> > information about the kernel module is available via .modinfo section of
> > the module.  In contrast, when the kernel module is compiled into the
> > kernel, that information is not available.
> >
> > Information about built-in modules is necessary in the following cases:
> >
> > 1. When it is necessary to find out what additional parameters can be
> > passed to the kernel at boot time.
> >
> > 2. When you need to know which module names and their aliases are in
> > the kernel. This is very useful for creating an initrd image.
>=20
> I would just keep it in the vmlinux as a non loadable segment, which
> won't make it into bzImage. vmlinux passed around anyways, and
> it's easier to handle than extra files, and it already has plenty
> of metadata in it.

Not for all architectures bzImage is created. Also not all distros pack
vmlinux and requiring them to start doing this for a few kilobytes seems
to me wrong.

As follow up I plan to add support of kernel.builtin.modinfo to kmod. The
kmod takes information only from /lib/modules/KVER and does not require the
kernel itself.

--=20
Rgrds, legion


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