From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 03 Oct 2005 11:12:10 +0100 (BST) Received: from extgw-uk.mips.com ([62.254.210.129]:54025 "EHLO bacchus.net.dhis.org") by ftp.linux-mips.org with ESMTP id S8133444AbVJCKKM (ORCPT ); Mon, 3 Oct 2005 11:10:12 +0100 Received: from dea.linux-mips.net (localhost.localdomain [127.0.0.1]) by bacchus.net.dhis.org (8.13.4/8.13.1) with ESMTP id j93AA4MW001842; Mon, 3 Oct 2005 11:10:07 +0100 Received: (from ralf@localhost) by dea.linux-mips.net (8.13.4/8.13.4/Submit) id j919S78l009207; Sat, 1 Oct 2005 10:28:07 +0100 Date: Sat, 1 Oct 2005 10:28:07 +0100 From: Ralf Baechle To: "Maciej W. Rozycki" Cc: Andrew Isaacson , linux-mips@linux-mips.org Subject: Re: [patch 1/5] SiByte fixes for 2.6.12 Message-ID: <20051001092807.GD14463@linux-mips.org> References: <20050622230042.GA17919@broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 9112 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips On Thu, Jun 23, 2005 at 12:01:57PM +0100, Maciej W. Rozycki wrote: > Well, the flag is not really to specify whether the common code is to be > used or not. It's about whether the TLB is like that of the R4k. > Actually it's always been a mystery for me why the common code cannot be > used for the SB1, but perhaps there is something specific that I could > only discover in that "SB-1 Core User Manual" that I yet have to see, > sigh... > > Of course if your TLB is indeed different from that of the R4k, then you > shouldn't be setting cp0.config.mt to 1 in the first place... The reason was primarily the tiny bit of extra performance because the SB1 doesn't need the hazard handling overhead. Also tlb-sb1 has a few changes that are needed to initialize a TLB in undefined state after powerup. That was needed to run Linux on firmware-less SB1 cores. Ralf