Specifying a device tree for psim within gdb

[Julien]

Hi,

I'm using gdb 5.0 on a linux x86 box, configured with
--target=powerpc-unknown-eabi. I want to debug a raw memory image (my
exec+some data) using the psim simulator.

 When I run the simulator directly (powerpc-unknown-eabi-run), I specify
a device-tree (whith a 'file' device to load my image). 
But when I use the debugger I don't know how to specify a device-tree.
The psim doc in sources.redhat.com talks about an attach patch but all
the links seem to be broken. 
Does someone have this patch ? Or is there another way to specify the
device tree within gdb ?

Thanks in advance,

    Julien.