Re: [linuxsh-dev] Cache bug on SH-3/4

[David M. <da...@sn...>]

Jivin Paul Mundt lays it down ...
> David,
> 
> Interesting. I've been testing on my Solution Engines .. 7709A and 7750.
> The 7751R has a vastly different cache configuration. Does your

I wouldn't say the 7751/7750 and the 7751R are that different code wise
to manage it,  just the extra ways to deal with.  Of course underneath
they may be plenty different ;-)

> arch/sh/mm/cache-sh4.c properly deal with the multiple ways?

Yes.  I would have tried it on a 7751 but it's net chip has gone west
and I am working from home (friday night),  so I won't be able to try it
till monday.

> I've also only tested this using write-back. I suppose I should give
> write-through a try as well, but since it's mostly a reading issue, I
> doubt that'll have much of an effect.

I am using copyback/write back. 

> Also, are you running stock LinuxSH CVS? or are you on a proprietary
> vendor tree that might have some other flushing happening somewhere?

I am running a mostly stock Linus kernel with patches for our targets.

Actually,  I just tried it again in compatibility mode (ie., stock 7751),
also worked fine.

The cache-sh4.c I used in the test is a mega hack version I used to get
multiple ways going (with experimentation code still in there).  I can
send you a copy if you want.  It currently has the 7751R support
hardcoded on,  but the current version has it disabled,  not that it
seems to matter in practice if you use the 7751R code on the 7751.

Cheers,
Davidm

> On Fri, 2003-02-14 at 09:36, David McCullough wrote:
> > I just tried this on my 2.4.17 kernel on the 7751R/SH4 with no crash
> > and it output 0 as I suspect it is supposed to.  I can try some more
> > platforms/combos monday when I am back in the office if you like.
> > 
> > Not sure that it worked for me means much though,  could be just be the
> > cache state/entries are quite different between our platforms.
> > 
> 
> Regards,
> 
> -- 
> Paul Mundt <pau...@ti...>
> TimeSys Corporation



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