[Buildroot] Kernel headers from an externally built kernel

[Buildroot] Kernel headers from an externally built kernel

[Wagner, Scott]

Hello,

 

I would like to use buildroot to create a root file system only - I have
an external toolchain and an external cross-built kernel made with that
toolchain.

 

How do I configure buildroot to reference the external kernel's headers?
In poking through the makefiles, it looks like this is possible, but I
have not yet found a way to specify it through menuconfig or by feeding
environment variables to make.  I'm currently building with
BR2_KERNEL_none=y.

 

I think that as a result buildroot is trying to use the host platform's
kernel headers, because the busybox build fails looking for an mtd
header file, which is not present in the host's kernel headers - but
this is just a guess.

 

Any ideas?  Thanks in advance ...

 

Scott Wagner
Rochester, NY US

 

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[Buildroot] Kernel headers from an externally built kernel

[Thomas Petazzoni]

On Thu, 6 May 2010 12:52:13 -0400
"Wagner, Scott" <swagner@vanteon.com> wrote:

> I would like to use buildroot to create a root file system only - I have
> an external toolchain and an external cross-built kernel made with that
> toolchain.
> 
> How do I configure buildroot to reference the external kernel's headers?
> In poking through the makefiles, it looks like this is possible, but I
> have not yet found a way to specify it through menuconfig or by feeding
> environment variables to make.  I'm currently building with
> BR2_KERNEL_none=y.
> 
> I think that as a result buildroot is trying to use the host platform's
> kernel headers, because the busybox build fails looking for an mtd
> header file, which is not present in the host's kernel headers - but
> this is just a guess.

In external toolchain mode, Buildroot simply uses the kernel headers as
available in the external toolchain. There is no option to use other
kernel headers, as it wouldn't make sense: kernel headers *are* part of
the external toolchain.

Concerning the MTD build problem, you may want to apply the patch
http://git.buildroot.net/~tpetazzoni/git/buildroot/patch/?id=93abe41eefbc1cea9b9a457011f66037772f4265.

Regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com