Hello Ulrich,
I'm on a freescale mx53 (single core, cortex a8) and trying to find a nasty problem in our $CUSTOMER's application. Working hardware watch point support in gdb should solve the problem, or at least brings us a big step forward. I stumbled over your about three years old thread[1] about the cortex a8 memory mapped debug registers problem. Do I understand correctly, that you had a8 watch point running on at least one board? Have you got any code and or pointers to get watch point support running?
regards, Marc Kleine-Budde
[1] http://lists.linaro.org/pipermail/linaro-toolchain/2011-February/000820.html