From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Mon, 22 Mar 2010 15:59:28 +0100 (CET) Received: from localhost.localdomain ([127.0.0.1]:57105 "EHLO h5.dl5rb.org.uk" rhost-flags-OK-OK-OK-FAIL) by eddie.linux-mips.org with ESMTP id S1492201Ab0CVO7U (ORCPT ); Mon, 22 Mar 2010 15:59:20 +0100 Received: from h5.dl5rb.org.uk (localhost.localdomain [127.0.0.1]) by h5.dl5rb.org.uk (8.14.3/8.14.3) with ESMTP id o2MExIli010416; Mon, 22 Mar 2010 15:59:19 +0100 Received: (from ralf@localhost) by h5.dl5rb.org.uk (8.14.3/8.14.3/Submit) id o2MExIHk010414; Mon, 22 Mar 2010 15:59:18 +0100 Date: Mon, 22 Mar 2010 15:59:18 +0100 From: Ralf Baechle To: Sebastian Andrzej Siewior Cc: linux-mips@linux-mips.org Subject: Re: [PATCH] mips/mm: fix module support on SiByte Message-ID: <20100322145918.GR4554@linux-mips.org> References: <20100321110241.GA25569@Chamillionaire.breakpoint.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100321110241.GA25569@Chamillionaire.breakpoint.cc> User-Agent: Mutt/1.5.20 (2009-08-17) 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: 26289 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 Sun, Mar 21, 2010 at 12:02:41PM +0100, Sebastian Andrzej Siewior wrote: > Since commit 656be92f aka "Load modules to CKSEG0 if > CONFIG_BUILD_ELF64=n" module support is broken on 64bit. Since then > modules arr loaded into 32bit compat adresses which are sign extended > 64bit addresses. The SiByte war handler was not updated and those > addresses were not recognized by the TLB hadling. > This patch fixes this by shifting away the upper bits including the R > and Fill bits. Now we compare VPN2 of C0_ENTRYHI against the matching > bits at C0_BADVADDR. Good detective work but I'll check against the errata documents (which are non-public, sigh ...) before applying your patch. The M3 workaround in which you found this bug is currently applied to all Sibyte SB1 cores while probably only a relativly small number of the cores in circulation are affected so we should refine the workaround to be only applied if the System Revision Register indicates a system older than revision C0. This could get rid of 6 instructions which according to the usual rule of thumb would result in a speedup of ~ 3%. Ralf