I'm not sure which exception you are experiencing, but most likely to be a data abort which happens if the access is beyond valid address space

please have a check with your board/xxxx/config.mk and see if TEXT_BASE is pointed to a valid address, usually the address you want your u-boot to be running at.

If your boot-up process will involve a relocation from flash to RAM, please also check you enabled that relocation process, it's usually controlled by some macro, whic I dont' remember clearly