Could anyone explain me what the kernel build tree is?
What files does it include?
How can I obtain it from a cross-compiled kernel source (e.g. 3.4.0)?
well the kernel build tree, is the kernel source itself
to get it an "install" it you should:
I think you can download it as well via apt like
With the information that you want to cross-compile your kernel to load it in an external device, I will assume that you want to do it for an arm-based device http://www.arm.linux.org.uk/docs/kerncomp.php if it's not, you can easily adapt it to another plataform
I recently started Kernel development and I thought I share a couple of resources with you which I find to be very informative. First lets begin with the Kernel Newbies and their section on how to build the kernel. Please visit this site to read more:
The other side I would liket to share is the Book from Georg Kroah-Hartmann that is available online here:
Also, there are different kernel trees available such as the regular stable Linux tree and the linux-next tree which ends in –rc# (you will understand what I mean by reading Hartmann’s book). The Linux-next kernel is the one that is currently developed to be the next stable version of the kernel. I hope this information will support your goals with the kernel and you enjoy the resources.