[PATCH 3/6] 8xx: invalidate non present TLBs

Dan Malek dan at embeddedalley.com
Fri Oct 9 07:11:07 EST 2009

On Oct 8, 2009, at 12:22 PM, Joakim Tjernlund wrote:

> hare are comments in the kernel that dcbst wrongly
> generates TLB Errors with store set on 8xx. Is this really so?
> Should dcbst always trap as a load?

There are many comments written about 8xx as various
behavior was discovered.  Worse, some of these details
would be different among the different processor versions.
You need to be careful and test as many different part
versions as possible to ensure you have everything
covered.....  then someone will find a part that doesn't
quite work, "fix" it, and break others :-)

In this particular case, the PEM does state dcbst is treated
as a load, but from experience we know 8xx doesn't work
that way.  Of course, since dcbst is a store operation,
you could argue that 8xx got it correct :-)

Have fun!

	-- Dan

More information about the Linuxppc-dev mailing list