From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Thu, 09 Jan 2003 20:09:13 +0000 (GMT) Received: from cpe.atm2-0-1031142.0x50c4469e.albnxx9.customer.tele.dk ([IPv6:::ffff:80.196.70.158]:33285 "EHLO localhost.localdomain") by linux-mips.org with ESMTP id ; Thu, 9 Jan 2003 20:09:12 +0000 Received: from linux-mips.org (localhost.localdomain [127.0.0.1]) by localhost.localdomain (8.11.2/8.11.2) with ESMTP id h09KA2L01409; Thu, 9 Jan 2003 21:10:02 +0100 Message-ID: <3E1DD719.2464A916@linux-mips.org> Date: Thu, 09 Jan 2003 21:10:01 +0100 From: Carsten Langgaard X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.20 i686) X-Accept-Language: en MIME-Version: 1.0 To: Ralf Baechle CC: Mike Uhler , "Maciej W. Rozycki" , Dominic Sweetman , linux-mips@linux-mips.org Subject: Re: [patch] Use XKPHYS for 64-bit TLB flushes References: <200301081933.h08JX1F09754@uhler-linux.mips.com> <20030108204408.A27888@linux-mips.org> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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: 1114 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: carstenl@linux-mips.org Precedence: bulk X-list: linux-mips Ralf Baechle wrote: > On Wed, Jan 08, 2003 at 11:33:01AM -0800, Mike Uhler wrote: > > > > They do are different: KSEG0+entry*0x2000, likewise for XKPHYS -- see the > > > patch. > > > > This is precisely what we use for our internal testing (which is also > > exported to MIPS32 and MIPS64 architecture licensees) to initialize the > > TLB. I have not yet seen a case where this fails, and would be interested > > in hearing about any case where it does fail. > > We used to use just KSEG0 instead of KSEG0+entry*0x2000. That was running > fine over years but had to be changed for the sake of two CPUs afair. There > was some discussion on this list about this and I accepted the change by that > time because Kevin imho correctly argued that the spec left it unspecified > if an implementation is feeding addresses in an unmapped address space > though the TLB. > All MIPS's CPUs need these unique TLB entries otherwise you get a machine check error. Inspired by Kevin Kissell's changes to openBSD, I made the above change (KSEG0+entry*0x2000) to the TLB routine in linux. It was done when we first tried to boot linux on the MIPS 4Kc CPU, a couple of years ago. > > Ralf