From: Ralf Baechle <ralf@oss.sgi.com>
To: Jun Sun <jsun@mvista.com>
Cc: linux-mips@fnet.fr, linux@cthulhu.engr.sgi.com, ralf@oss.sgi.com
Subject: Re: Turning off cache ...
Date: Fri, 28 Jul 2000 03:08:36 +0200 [thread overview]
Message-ID: <20000728030836.A1906@bacchus.dhis.org> (raw)
In-Reply-To: <3980D95A.5949E980@mvista.com>; from jsun@mvista.com on Thu, Jul 27, 2000 at 05:52:42PM -0700
On Thu, Jul 27, 2000 at 05:52:42PM -0700, Jun Sun wrote:
> Is there is easy way to turn off caching entirely? I understand I need
> to set k0 bits in config register. What about those C bits in TLB
> entries? My CPU only has primary cache.
The C bits are per page, the k0 bits are for KSEG0. If you want to
turn of caching, then you need to:
- change the k0 bits to uncached on startup, then flush the caches or a
writeback might corrupt your data.
- change the caching mode of the usermode pages by modifying the
definitions for PAGE_NONE etc. in pgtable.h.
- comment out the cache Create_Dirty_Exclusive instructions in r4xx0.c,
using them on uncached pages would corrupt data.
Which will make the kernel crawl awfully ...
Ralf
next prev parent reply other threads:[~2000-07-28 1:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-07-28 0:52 Turning off cache Jun Sun
2000-07-28 1:08 ` Ralf Baechle [this message]
2000-07-29 2:43 ` Jun Sun
2000-07-29 2:43 ` Jun Sun
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