[Buildroot] Using Ram-Resident Filesystem

I am doing cross-development using Linux with a Lauterbach TRACE32
In-Circuit Debugger (ICD).

I would like to substitute my mtd0 to be a RAM address (normally FLASH),
where I store my SQUASHFS filesystem.  In other words, I want my
environment/filesystem to be as close to what will be used when the target
runs in FLASH without the ICD.

Question:

How can I easily fake-out Linux to use the RAM-resident read-only filesystem
instead of it being FLASH-resident?  As far as the kernel is concerned, the
only difference should be where it reads the filesystem.

Can the above be done easily?  I would rather not use a RAM-Disk or network
filesystem.

Best Regards,
Jerry