[fleedwood]

What looks like the equivalent function for Linux - setup_hub_mask() - incorporates the "nasid" (I assume each processor board in an Origin2000 has its own nasid and each node of an Origin200 has its own nasid - am I correct with that?) which it determines from the current processor but otherwise looks like it does pretty much the same as OpenBSD's version.

 nasid is the number of the node board (hub plus 2 CPUs), which also defines the 4GB address range of node.

For a better understanding of the archtiecture look ath the Orign and Onyx2 Programmers Reference Manual (007-3410-001.pdf).