how to get a hierarchical display of makefiles?

[Robert P. J. Day]

  more specifically, i'm trying to follow the hierarchical layout of
the makefiles in the linux kernel and, if you've ever tried that,
you'll know it gets complicated in a hurry.

  is there a tool that can show, at a high level, the inclusions
starting at the top-level makefile?  or some way to summarize the
final rule for a target after all makefile processing is done?
thanks.

rday