From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by oss.sgi.com (8.11.2/8.11.3) id f5P4ix619425 for linux-mips-outgoing; Sun, 24 Jun 2001 21:44:59 -0700 Received: from orion.mvista.com (gateway-1237.mvista.com [12.44.186.158]) by oss.sgi.com (8.11.2/8.11.3) with SMTP id f5P4iwV19422 for ; Sun, 24 Jun 2001 21:44:59 -0700 Received: (from jsun@localhost) by orion.mvista.com (8.9.3/8.9.3) id VAA18399; Sun, 24 Jun 2001 21:42:32 -0700 Date: Sun, 24 Jun 2001 21:42:32 -0700 From: Jun Sun To: "Kevin D. Kissell" Cc: linux-mips@oss.sgi.com Subject: Re: CONFIG_MIPS_UNCACHED Message-ID: <20010624214232.A18389@mvista.com> References: <3B34BE3B.B72D40F1@mvista.com> <01ee01c0fc08$66e81e80$0deca8c0@Ulysses> <3B34D6AC.9EACA819@mvista.com> <020c01c0fc21$51256760$0deca8c0@Ulysses> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <020c01c0fc21$51256760$0deca8c0@Ulysses>; from kevink@mips.com on Sat, Jun 23, 2001 at 10:15:49PM +0200 Sender: owner-linux-mips@oss.sgi.com Precedence: bulk On Sat, Jun 23, 2001 at 10:15:49PM +0200, Kevin D. Kissell wrote: > > > Since the kernel cache attribute is never initialized before > > > ld_mmu_{whatever} is invoked, and since that Config field > > > does not have a well-defined reset state on many MIPS > > > CPUs, it would appear that we are in effect trusting the > > > bootloader to have done something reasonable like > > > set kseg0 to be non-cachable or write-through, either > > > of which would be safe for the current code. > > > > I think you just proposed a fix: check current config register when we > turn > > off cache. Thanks. :-) > > That's a heuristic at best. If the config register comes up random, > it can appear to be sane even though the cache is in fact uninitialized. > For any practical reasons, we can assume there is a loader for Linux, and we can assume loader does not run with a random config register. Jun