From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.sgi.com (localhost [127.0.0.1]) by oss.sgi.com (8.12.5/8.12.5) with ESMTP id g6UMjtRw006349 for ; Tue, 30 Jul 2002 15:45:55 -0700 Received: (from majordomo@localhost) by oss.sgi.com (8.12.5/8.12.3/Submit) id g6UMjtLc006348 for linux-mips-outgoing; Tue, 30 Jul 2002 15:45:55 -0700 X-Authentication-Warning: oss.sgi.com: majordomo set sender to owner-linux-mips@oss.sgi.com using -f Received: from dea.linux-mips.net (shaft16-f207.dialo.tiscali.de [62.246.16.207]) by oss.sgi.com (8.12.5/8.12.5) with SMTP id g6UMjlRw006339 for ; Tue, 30 Jul 2002 15:45:49 -0700 Received: (from ralf@localhost) by dea.linux-mips.net (8.11.6/8.11.6) id g6UMl2N02372; Wed, 31 Jul 2002 00:47:02 +0200 Date: Wed, 31 Jul 2002 00:47:02 +0200 From: Ralf Baechle To: "Maciej W. Rozycki" Cc: Carsten Langgaard , linux-mips@fnet.fr, linux-mips@oss.sgi.com Subject: Re: [patch] MIPS64 R4k TLB refill CP0 hazards Message-ID: <20020731004702.A2142@dea.linux-mips.net> References: <3D4681DE.7BE793C9@mips.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from macro@ds2.pg.gda.pl on Tue, Jul 30, 2002 at 02:44:32PM +0200 X-Spam-Status: No, hits=-4.4 required=5.0 tests=IN_REP_TO version=2.20 X-Spam-Level: Sender: owner-linux-mips@oss.sgi.com Precedence: bulk On Tue, Jul 30, 2002 at 02:44:32PM +0200, Maciej W. Rozycki wrote: > Since the handler is critical for performance, it would be desireable to > have separate versions tuned for particular CPUs. The branch for the > R4400 seems appropriate as it works unlike the documented code: the > R4000/R4400 manual as available from the MIPS site states a single > intervening instruction is needed before the last move to EntryLo and a > "tlbwr" or "tlbwi" (see Table F-1 and F-2). So I conclude the branch is > really a workaround for a kind of erratum or a specification change. Nope, on R4000 four cycles are needed between the tlbwr and a eret instruction; on the R4600 just two. Ralf