From Rafal's commit for mipseb (which applies here too):
WARNING: Binutils 2.11.2 (maybe earlier) changed the MIPS ABI, so any
shared libs built by this toolchain WILL NOT WORK without either a whack
to BFD to fix that or a patch to ld_elf.so to work around it. I need to
chase the binutils folks on this issue still.