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Date:   Fri, 8 Mar 2019 15:04:49 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     "Enrico Weigelt, metux IT consult" <lkml@metux.net>
Cc:     Joel Fernandes <joel@joelfernandes.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
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        Daniel Colascione <dancol@google.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
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        Karim Yaghmour <karim.yaghmour@opersys.com>,
        Kees Cook <keescook@chromium.org>,
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Subject: Re: [PATCH v4 1/2] Provide in-kernel headers for making it easy to
 extend the kernel
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On Fri, Mar 08, 2019 at 02:57:24PM +0100, Enrico Weigelt, metux IT consult wrote:
> On 08.03.19 14:42, Joel Fernandes wrote:
> 
> Hi folks,
> 
> > That sounds like it could be useful. I don't see any reason off the
> > top why that would not be possible to add to the list of archived
> > files in the future. The patch allows populating the list of files
> > from Kbuild using ikh_file_list variable.
> 
> It seems the whole thing's going into a direction where a whole own
> subtopic is coming up: compressed built-in filesystem.
> 
> Haven't had a deeper thought about it yet, whether or not existing
> filesystems like squashfs, initramfs, etc are the right thing for that,
> or something new should be invented, but a generic mechanism for
> compiled-in compressed (ro) filesystems could also be interesting
> for very small devices, that perhaps even dont need any persistence.
> 
> Some requirements coming up in mind:
> 
> 1. it shall be possible to have any number of instances - possibly by
>    separate modules.
> 2. it shall be possible to use an bootloader/firmware provided image
>    (so it can serve as initrd)
> 2. data should stay compressed as long as possible, but uncompressed
>    data might be cached - do decompression on-demand
> 3. only needs to be ro (write access could be done via unionfs+friends)
> 4. it shall be swappable (if swap is enabled)
> 
> In that scenario, these in-kernel headers would just one consumer,
> I can imagine lots of others.

I too want a pony :)

Until then, I think this feature should not be bikeshedded to death.  It
fits a real need, is simple (modulo the Kbuild interactions), and is
optional for those that do not wish to waste the memory.

thanks,

greg k-h