[Buildroot] grub compilation issue (x86_64 target)

[vbr vbr]

Thanks for the quick answer.

Just playing to see the feasability of using buildroot as a diagnostic OS on
x86_64 servers. It is not meant to be the real OS running on these servers.

One thing I am confused about is that ISO support was added recently for
x86_64 targets in buildroot and it seems that ISO requires grub (from
menuconfig). If grub is not supported, then ISO can't be supported either
for x86_64. Also, I am pretty sure that grub was building fine on buildroot
2010.05 for x86_64. I could check that again.

Thanks
Vincent


On Wed, Jul 21, 2010 at 11:59 AM, Thomas Petazzoni <
thomas.petazzoni at free-electrons.com> wrote:

> Hello,
>
> On Wed, 21 Jul 2010 08:11:24 -0700
> vbr vbr <vvvg77 at gmail.com> wrote:
>
> > There seems to be a compilation issue in the grub area with
> > buildroot's latest code (git) with x86_64 target. (or maybe it's just
> > my setup) After googling a little bit, the type of error shown in the
> > config.log seems to indicate a missing library.
> > I attached the config log and my buildroot config.
>
> Yes, this is due to the fact that Grub uses the x86_64
> cross-compilation toolchain with the -m32 gcc switch, in order to
> produce 32 bits binaries. Unfortunately, the toolchain that Buildroot
> produces is a pure 64 bits toolchain, so it cannot support the -m32
> switch.
>
> I see four possible solutions to this :
>
>  *) Extend the Buildroot toolchain build system so that it can produce
>    a 32/64 bits multilib toolchain that supports -m32. As embedded on
>    x86_64 is very uncommon, I'm not sure we'll find someone who is
>    interested to work on this.
>
>  *) Extend Crosstool-NG so that it can produce such a 32/64 bits
>    toolchain and then use it as an external toolchain. I've started to
>    work on multilib support for Crosstool-NG, but it's far from being
>    ready at the moment.
>
>  *) Somehow make Buildroot generate two toolchains, a 32 bits one used
>    to compile Grub, and a 64 bits toolchain to compile all the rest.
>    Since would involve fairly large and complicated modifications,
>    which I'm not sure we're ready to do for such a untypical use-case.
>
>  *) Mark Grub as broken on x86_64 so that it cannot be compiled. I
>    think this is the solution we're going to choose. Grub can always
>    be compiled outside of Buildroot, and the build of bootloaders is
>    not the biggest added value of embedded build systems such as
>    Buildroot anyway.
>
> Just out of curiosity, what is your use case for using Buildroot on a
> x86_64 machine ? Is it just for experimenting/playing, or are they real
> embedded products out there using x86_64 and that have footprint
> requirements that make using Buildroot an interesting thing compared to
> using full-blown distributions ?
>
> Thanks,
>
> Thomas
> --
> Thomas Petazzoni, Free Electrons
> Kernel, drivers, real-time and embedded Linux
> development, consulting, training and support.
> http://free-electrons.com
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