[U-Boot] Loading Linux Image on AT91SAM9263-EK

I am trying to port linux on the same board as mentioned in the subject. I want to know how to configure the crosscompiler to build uimage or an image of the kernel. I have got the other requirements like at91bootstrap boot.bin and u-boot.bin ready configured for the board. I have also found root file system and configured it as a jffs2 ext. The kernel i am not able to build as i dont know what crosscompiler to use. I have used buildroot to get the above images but buildroot doesnt have the option to configure for at91sam9263 (or does it ?? i didnt get one though) Please advise how to proceed.