From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fed1rmmtao01.cox.net (fed1rmmtao01.cox.net [68.230.241.38]) by ozlabs.org (Postfix) with ESMTP id EB3B72BF12 for ; Thu, 6 Jan 2005 04:37:00 +1100 (EST) Date: Wed, 5 Jan 2005 10:36:58 -0700 From: Tom Rini To: Steven Rostedt Message-ID: <20050105173658.GE4213@smtp.west.cox.net> References: <313680C9A886D511A06000204840E1CF0A647421@whq-msgusr-02.pit.comms.marconi.com> <1104256077.20042.125.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1104256077.20042.125.camel@localhost.localdomain> Cc: "Povolotsky, Alexander" , linuxppc-embedded@ozlabs.org Subject: Re: simple bootloader 2.6.10-rc3 8xx List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Dec 28, 2004 at 12:47:57PM -0500, Steven Rostedt wrote: > On Tue, 2004-12-28 at 12:28 -0500, Povolotsky, Alexander wrote: > > Hi! (Thanks !) > > > > I guess I need some more education - since I am getting my problem right at > > the boot - is > > I-Cache enabled (by default ?) for 8xx on 2.6 at the booting ? - I do not > > see anything in .config > > which controls it (or I am missing it there ?) > > How (where and at what point during the boot)-) I could disable I-Cache ? > > Since you where able to get to the prekernel portion (that was > relocated) I don't think you have a problem with caches, unless for some > reason the pre-kernel can relocate itself, but it doesn't know to > refresh the cache after relocating the actual kernel. The in-kernel bootwrapper codes does indeed relocate itself (overlap isn't a problem either, except for a small window. All of this can be avoided if you link the kernel where it will be loaded into memory by the firmware as well), but it should also do all needed cache flushing. But as has been said before, since the CPU15 errata doesn't exist with i-cache disabled, the simple workaround would be to disable the i-cache as quickly as possible from the head.S portions of the in-kernel bootwrapper and make sure we don't re-enable it later on (I _think_ we do for speed reasons). -- Tom Rini http://gate.crashing.org/~trini/