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From: Brian Waite <waite@skycomputers.com>
To: Gary Thomas <gary@mlbassoc.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-dev@lists.linuxppc.org>
Subject: Re: Disable cache on 74xx
Date: Thu, 20 Feb 2003 08:55:12 -0500	[thread overview]
Message-ID: <200302200855.12224.waite@skycomputers.com> (raw)
In-Reply-To: <1045694930.22231.6567.camel@hermes.chez-thomas.org>


According to The User's Manual, the data cache instructions become no-ops if
the data cache is disabled.

Thanks
Brian
On Wednesday 19 February 2003 5:48 pm, Gary Thomas wrote:
> On Wed, 2003-02-19 at 14:07, Benjamin Herrenschmidt wrote:
> > On Wed, 2003-02-19 at 21:52, Brian Waite wrote:
> > > Hi all,
> > > 	I am trying to hunt down a memory controller configuration problem and
> > > I have been asked to disable all caching so as to remove it from the
> > > equation. I can easl disable L2 but when I start ucking with the WIMG
> > > bits to set cache inhibit, The kernel panics with stack overflows. Does
> > > anyone know where or what I have to set to disable caching?
> >
> > Hrm... set L2 and L3 off, then hack HID0 to disable L1 ?
>
> There are other problems with this.  With the caches disabled
> (via HID0) all data cache instructions (like DCBF) will fail.
> There are some of these in the kernel itself, but beware that
> GLIBC has it's own set.
>
> ... totally disabling the data CACHE with Linux is non-trivial.


** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2003-02-20 13:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-02-19 20:52 Disable cache on 74xx Brian Waite
2003-02-19 21:07 ` Benjamin Herrenschmidt
2003-02-19 22:48   ` Gary Thomas
2003-02-20 13:55     ` Brian Waite [this message]
2003-02-20 14:01       ` Gary Thomas
2003-02-20 14:09         ` Geert Uytterhoeven
2003-02-20 15:23           ` Dan Malek
2003-02-20 15:47             ` Brian Waite
2003-02-20 15:54               ` Gary Thomas
2003-02-20 15:55               ` Benjamin Herrenschmidt
2003-02-20 16:14               ` Dan Malek
2003-02-20 16:51                 ` Mark A. Greer
2003-02-20 14:09         ` Brian Waite

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