From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751280AbWDNQuE (ORCPT ); Fri, 14 Apr 2006 12:50:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751282AbWDNQuE (ORCPT ); Fri, 14 Apr 2006 12:50:04 -0400 Received: from sccimhc91.asp.att.net ([63.240.76.165]:8700 "EHLO sccimhc91.asp.att.net") by vger.kernel.org with ESMTP id S1751280AbWDNQuC (ORCPT ); Fri, 14 Apr 2006 12:50:02 -0400 From: Steve Snyder To: Alan Cox Subject: Re: Where to call L2 cache enabling code from? Date: Fri, 14 Apr 2006 12:49:49 -0400 User-Agent: KMail/1.9.1 Cc: Linux Kernel Mailing List References: <200604141105.43216.swsnyder@insightbb.com> <1145029574.17531.26.camel@localhost.localdomain> In-Reply-To: <1145029574.17531.26.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200604141249.49366.swsnyder@insightbb.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Friday 14 April 2006 11:46 am, Alan Cox wrote: > On Gwe, 2006-04-14 at 11:05 -0400, Steve Snyder wrote: > > I have a machine in which the BIOS does not enable the Pentium3's L2 > > cache at boot time. At what point in the kernel init process > > can/should I call the code to enable the cache? > > What part of the cache setup is not done correctly ? The mtrr registers > or other things ? It's not that the kernel is failing in any respect. The BIOS simply does not enable the on-CPU L2 cache at power-on. (The machine originally shipped with a Pentium2, and doesn't know how to enable the L2 cache on the Pentium3 that is now running in it.) I've got a small device driver that enables the L2 cache. It works fine when build as a module and loaded after booting has completed. My goal is to move the code into the kernel so that it is run early in the kernel init process. I expect that having the L2 cache go from "0KB" to 256KB will improve boot time greatly, as well as informing the kernel from the get-go of the true capabilities of this processor. Getting the code into the kernel image is a no-brainer. But once it is built into the kernel, at what point should I call it? Thanks for the response.