A few years ago the answer to this question was 'NO'. I wonder if things have changed?
Using a P1 programmed in 'C'.
At boot 32k is automagically loaded from the external memory into HUB memory. Eight 2k (max) blocks get loaded into the 8 COGs which start doing their own thing using COG RAM for storage etc. Can the full 32k of HUB, as it is now no longer needed by the COGs or boot process, be used as a contiguous block of RAM?