See this thread for a description of the issue and a patch, which is in Xilinx's fork of binutils but does not seem to have made it upstream: http://permalink.gmane.org/gmane.linux.uclinux.microblaze/11155 Basically, the issue is that gas thinks it can generate a 16-bit relative jump when there's a local definition of the function, even if that definition is weak and might be overridden by a strong definition that's outside of the 16-bit jump range. I'm in the process of porting musl libc to microblaze, and this issue is a show-stopper since we make heavy use of weak definitions.