> What's the intended usage for this? What code would care to know the config
> tree root and why?

IOKit emulation in COMPAT_MACH. There is some API to explore the device
tree from userland, and this includesgetting the root node.

Having a global pointing to the root device is probably the right way,
the problem will just be to find the name, since root_device is already
used. What do you think?

-- 
Emmanuel Dreyfus.  Cette signature vous est fournie telle quelle, sans 
aucune garantie de fonctionnement. En la lisant, vous acceptez 
implicitement tous les degats qu'elle pourrait causer, materiellement 
ou logiciellement.                                manu@netbsd.org