CONFIG_HIGHMEM on PPC

David Edelsohn dje at watson.ibm.com
Fri Jan 26 06:59:06 EST 2001


>>>>> Dan Malek writes:

Dan> Heh....64Gbyte is nothing, just a few more bits beyond 32....you
Dan> don't need 64-bits for this.  In fact, I had a revelation last
Dan> night where I thought we could even do this quite transparently
Dan> on PowerPCs with VSIDs or even context registers, anything that
Dan> implictly gives us a few more bits of virtual address.  Later
Dan> on that.....

	Yes, that is the exact purpose of the PowerPC addressing model.
While one user context is limited to 32-bit addresses, the system can map
a larger physical address range into the process's virtual address space.
The process even could handle this with OS cooperation using overlays.

David

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