Subject: Re: k0/k1 register while mulhi/mullo manipulation
To: Toru Nishimura <nisimura@itc.aist-nara.ac.jp>
From: Jason Thorpe <thorpej@nas.nasa.gov>
List: port-mips
Date: 02/24/2000 07:49:09
On Thu, 24 Feb 2000 14:32:10 +0900 (JST) 
 nisimura@itc.aist-nara.ac.jp (Toru Nishimura) wrote:

 > NetBSD/mips R3000/R4000 codes run USPACEs using wired TLB entries, but
 > they have their own unique KSEG2 addresses, i.e., NetBSD has no UADDR
 > any more, _the_ very archaic feature of UNIX.  (I'm still wondering why
 > KSEG0 range is not used)

KSEG0 could be used with the following caveats:

	- If you want more than 2 UPAGES, you *must* ensure that you can
	  allocate physically contiguous memory.

	- Otherwise, you only get one page of kernel stack.

One page might not be enough, but then again, it might be :-)

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>