From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 88894DDF08 for ; Wed, 1 Oct 2008 07:30:46 +1000 (EST) Subject: RE: Disabling L1 D-cache and side effects From: Benjamin Herrenschmidt To: Tirumala Reddy Marri In-Reply-To: References: <9323BAFB78DE7C4183466AD03F73EA424D46071D@SDCEXCHANGE01.ad.amcc.com> <20080929180455.GA19014@lixom.net> <20080929211401.GA22039@lixom.net> <1222758980.9006.43.camel@pasglop> Content-Type: text/plain Date: Wed, 01 Oct 2008 07:30:36 +1000 Message-Id: <1222810236.9006.54.camel@pasglop> Mime-Version: 1.0 Cc: Olof Johansson , linuxppc-dev@ozlabs.org Reply-To: benh@kernel.crashing.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2008-09-30 at 09:57 -0700, Tirumala Reddy Marri wrote: > Ben, > Thanks for the response. I am wondering how user space would get > affected by absence of L1 Dcache. You didn't answer my question :-) Well, as I said, things like lwarx/stwcx not working, dcbz taking alignment exceptions, etc... Ben. > Thanks, > Marri > > -----Original Message----- > From: Benjamin Herrenschmidt [mailto:benh@kernel.crashing.org] > Sent: Tuesday, September 30, 2008 12:16 AM > To: Tirumala Reddy Marri > Cc: Olof Johansson; linuxppc-dev@ozlabs.org > Subject: RE: Disabling L1 D-cache and side effects > > On Mon, 2008-09-29 at 14:38 -0700, Tirumala Reddy Marri wrote: > > Could you please point me to the which does the Critical error > > (Machine > > Check) recovery. BTW I am successful booting the Linux until rootfs is > > > being mounted. It fails to mount the Linux saying that blocks are > > corrupted in file system. I had to modify lots of initial bring up > > code to disable D-cache and make sure all TLB's are cache inhibited. > > Ando also made sure none of the misc_32.S , entry_32.S and head.S > > makes any references to d-cache. > > Why the heck are you doing that btw ? AFAIK, as Olof says, things like > atomic operations will not work, dcbz neither etc... it's likely that > even if you manage to plaster around all of this in the kernel, whatever > userspace code you'll try to run in userspace will blow up too... > > Cheers, > Ben.