In article <200211021530.gA2FUb914591@pl374.nas911.nara.nttpc.ne.jp>
itohy@netbsd.org wrote:

> I happen to try following change and the problem disappear.
> Here, we are clearing the TLB.  The original code clears TLB
> via address array, and new code does it via data array 1.

I just take a look at SH4 programming manual, but
I guess if you use UTLB data array 1 to invalidate TLB entries
there are follow problems:
(1) it does not clear VPN
(2) it might break other bits (cacheable, writethrough etc.)

BTW, there is an errata about TLB usage for SH3:
http://www.hitachisemiconductor.com/sic/resource/japan/eng/pdf/mpumcu/ms/tnsh7291ae.pdf
According to this doc, it's better to wrote 0xf0000000 to VPN on
invalidating TLB entries to avoid an exception on TLB
(which might cause another bug of SH3).

I think SH4 does not have this bug, but I guess it's still better
to use 0xf0000000 for VPN on invalidating TLB via address array.
---
Izumi Tsutsui
tsutsui@ceres.dti.ne.jp