There is some beta/experimental hardware watchpoint code in Frysk 0.3. Give it a try and file bugs. Use the “watch” command from fhpd to access it. Also note these are purely hardware watchpoints, so sizes are 1, 2 and 4 bytes  (and 8 bytes on x8664). Teresa is working on some code for 0.4 that allows chaining of watchpoints together to watch bigger spaces.