[Buildroot] grub compilation issue (x86_64 target)

[Paul Jones]

Could you just use the 32bit x86 rather than the x86_64? I do this myself
for testing and it works fine.

 

 

Paul.

 

 

From: buildroot-bounces at busybox.net [mailto:buildroot-bounces at busybox.net]
On Behalf Of vbr vbr
Sent: Thursday, 22 July 2010 5:09 AM
To: Thomas Petazzoni
Cc: buildroot at busybox.net
Subject: Re: [Buildroot] grub compilation issue (x86_64 target)

 

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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