Re: [patch] Use XKPHYS for 64-bit TLB flushes

[Ralf Baechle <ralf@linux-mips.org>]

On Wed, Jan 08, 2003 at 09:12:03PM +0100, Maciej W. Rozycki wrote:

>  Well, like it or not, CAMs do not like multiple matches -- up to a
> physical damage even.  So they should be avoided if possible.  While KSEG0
> won't match for any real address translation, there is a non-zero
> probability of executing a tlbp for it as a result of buggy code or
> execution gone wild (root running crashme?). 

I'm told the TLB Shutdown bit in the R4000 is basically implemented as an
overcurrent protection.  That is on many chips even a hit on several
entries won't cause a tlb shutdown until the matches do result in the
TLB drawing more than a certain current.

A tlbp on a KSEG0 address shouldn't happen.  If it's attempted we already
have worse problems.

  Ralf