Xen on ARM: upstream kernel compile fails with defconfig

[Zoltan Kiss <zoltan.kiss@citrix.com>]

Hi,

I'm trying to do a default ARM build to verify my grant mapping patches 
doesn't break build. I'm using latest net-next tree as a basis, and I'm 
trying to build it based this howto:

http://wiki.xenproject.org/wiki/Xen_ARMv7_with_Virtualization_Extensions/Allwinner

(note, the actual CPU doesn't matter to me, I just want a default build 
to succeed. Also, net-next is only used because that was checked out, 
and I assume it should work as well)

I'm doing cross-compilation, so my make looks like this:

PATH="/local/repo/arm/gcc-linaro-arm-linux-gnueabihf-4.8-2013.10_linux/bin/:$PATH" 
make -j8 O=../o-arm ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- zImage

For config I've tried sunxi_defconfig (which actually doesn't have Xen 
enabled) and arndale_ubuntu_defconfig from Julien's repo:

http://wiki.xenproject.org/wiki/Xen_ARMv7_with_Virtualization_Extensions/Arndale

However both cases the build fails quite early with the same error:

   CC      arch/arm/kernel/asm-offsets.s
In file included from /local/repo/linux-net-next/include/linux/cache.h:5:0,
                  from /local/repo/linux-net-next/include/linux/printk.h:8,
                  from /local/repo/linux-net-next/include/linux/kernel.h:13,
                  from /local/repo/linux-net-next/include/linux/sched.h:15,
                  from 
/local/repo/linux-net-next/arch/arm/kernel/asm-offsets.c:13:
/local/repo/linux-net-next/include/linux/prefetch.h: In function 
‘prefetch_range’:
/local/repo/linux-net-next/arch/arm/include/asm/cache.h:7:25: error: 
‘CONFIG_ARM_L1_CACHE_SHIFT’ undeclared (first use in this function)
  #define L1_CACHE_SHIFT  CONFIG_ARM_L1_CACHE_SHIFT

So far I figured out that autoconf.h is not included here, that CONFIG_ 
is defined there. But I'm not that familiar with the kernel build 
system, so I'm a bit stucked here. Probably I'm doing something 
trivially wrong, can someone help me?
Btw. on Julian's repo from the Arndale page I could compile, but that's 
too old for my patch to apply. My main goal is to compile an upstream 
kernel with Xen, and then check if my patch breaks it.

Regards,

Zoli