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Re: wrong SP restored after DBE exception

To: Ralf Baechle <ralf@linux-mips.org>
Subject: Re: wrong SP restored after DBE exception
From: Dave Johnson <djohnson+linux-mips@sw.starentnetworks.com>,
Date: Thu, 28 Sep 2006 10:34:57 -0400
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>, linux-mips@linux-mips.org
In-reply-to: <20060928142840.GB3394@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <17690.54995.407882.581783@zeus.sw.starentnetworks.com> <20060928130925.GA3394@linux-mips.org> <Pine.LNX.4.64N.0609281448310.3949@blysk.ds.pg.gda.pl> <20060928142840.GB3394@linux-mips.org>
Sender: linux-mips-bounce@linux-mips.org
Ralf Baechle writes:
> I would suggest to disable interrupts around accesses that potencially
> could result in DB exceptions and just to make sure he is not getting
> trapped by a non-blocking load by making some use of any value read
> from the device.  Writes could be posted depending on bus type.  So
> having a read from the same device would force the write to complete.
> 
>   Ralf

Ya, I was about to try that.  I could be getting an interrupt
between the time the read is issued and the timeout occurs on the
GBus.  Also, doing a dummy read on the GBus to a device that
shouldn't fault prior to (for reads) or after (for writes) the
potentially faulting one to force ordering seems like a good idea
too.


-- 
Dave Johnson
Starent Networks


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