Can gdb handle aliased memory regions ?

[MikeW <mw_phil@yahoo.co.uk>]

Target platform: STLinux / ST Micro Connect

On the target CPU, there is one region of physical memory that is accessible by
two different mapped memory address regions: one as cached memory and one as
uncached, eg.
 0x8000000 (virt cached)   -> 0x40000000 (phys)
 0xDF00000 (virt uncached) -> 0x40000000 (phys)

During the kernel init, there is a code sequence which switches between cached
and uncached (to update cache registers etc) and expects the execution to
proceed from eg. 0x80001234 to 0xDF001236.

Stepping with gdb is fine until the switchover point is reached,
whereupon gdb thinks it's lost control ('step[i]', 'next' or 'finish'
do not return to the (gdb) prompt), but of course the ms bits of
the PC just refer to the other region.

I note gbd has support for the older technique of overlays; is there any way to
tell gdb that the 0x8000... and 0xDF00... regions are actually the same physical
memory ?

Thanks.