From: Peter Horton <pdh@colonel-panic.org>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: Peter Horton <pdh@colonel-panic.org>, Jun Sun <jsun@mvista.com>,
Bob Breuer <bbreuer@righthandtech.com>,
linux-mips@linux-mips.org
Subject: Re: problems on D-cache alias in 2.4.22
Date: Tue, 18 May 2004 22:21:53 +0100 [thread overview]
Message-ID: <20040518212153.GA11783@skeleton-jack> (raw)
In-Reply-To: <20040518195055.GB2454@linux-mips.org>
On Tue, May 18, 2004 at 09:50:55PM +0200, Ralf Baechle wrote:
> On Tue, May 18, 2004 at 08:10:19PM +0100, Peter Horton wrote:
>
> > The kernel maps the page cache page into user space ... BANG! possible
> > D-cache alias.
> >
> > The kernel doesn't bother flushing the page cache page from the D-cache
> > as it's never accessed at it's page cache address.
>
> It is - after all the driver is copying the data to there. The same
> problem also exists in the ramdisk driver and there it has been fixed
> properly, it seems.
>
I had a dig around but couldn't decide where the proper fix should go.
> > The current fix in the Cobalt patches (2.4 & 2.6) just flushes the read
> > data out of the D-cache after every IDE insw()/insl(). This is the least
> > intrusive fix.
> >
> > Some Sparc machines also see this problem.
>
> Carelessly written PIO drivers on any architecture would suffer from this
> kind of problem.
>
Are you saying it's a driver problem ? :-)
P.
next prev parent reply other threads:[~2004-05-18 21:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-18 18:17 problems on D-cache alias in 2.4.22 Bob Breuer
2004-05-18 18:17 ` Bob Breuer
2004-05-18 18:45 ` Jun Sun
2004-05-18 19:10 ` Peter Horton
2004-05-18 19:50 ` Ralf Baechle
2004-05-18 18:24 ` Alan Cox
2004-05-18 21:21 ` Peter Horton [this message]
2004-05-18 22:25 ` Jun Sun
2004-05-18 23:29 ` Peter Horton
2004-05-18 20:02 ` Ralf Baechle
2004-05-18 20:10 ` Thiemo Seufer
-- strict thread matches above, loose matches on Subject: below --
2004-05-13 22:05 Bob Breuer
2004-05-13 22:05 ` Bob Breuer
2004-05-14 2:59 ` wuming
2004-05-14 7:52 ` Peter Horton
2004-05-15 0:12 ` Ralf Baechle
2004-05-15 12:31 ` Fuxin Zhang
2004-05-13 6:52 wuming
2004-05-14 7:45 ` Peter Horton
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