From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sat, 10 Jul 2004 08:34:20 +0100 (BST) Received: from [IPv6:::ffff:213.189.19.80] ([IPv6:::ffff:213.189.19.80]:55558 "EHLO mail.kpsws.com") by linux-mips.org with ESMTP id ; Sat, 10 Jul 2004 08:34:15 +0100 Received: (qmail 46330 invoked by uid 89); 10 Jul 2004 07:33:57 -0000 Received: from unknown (HELO mail.kpsws.com) (127.0.0.1) by localhost with SMTP; 10 Jul 2004 07:33:57 -0000 Received: from 80.56.56.210 (SquirrelMail authenticated user pulsar@kpsws.com) by mail.kpsws.com with HTTP; Sat, 10 Jul 2004 09:33:57 +0200 (CEST) Message-ID: <1557.80.56.56.210.1089444837.squirrel@mail.kpsws.com> In-Reply-To: References: Date: Sat, 10 Jul 2004 09:33:57 +0200 (CEST) Subject: Re: Strange, strange occurence From: "Niels Sterrenburg" To: "S C" Cc: linux-mips@linux-mips.org Reply-To: niels.sterrenburg@philips.com User-Agent: SquirrelMail/1.4.0 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 X-Priority: 3 Importance: Normal 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: 5441 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: niels.sterrenburg@philips.com Precedence: bulk X-list: linux-mips Hi Steve, When you set a breakpoint with the ice and step through, for each step the ICE set's a breakpoint on the next instruction: e.g.: - modifies next instruction in memory (via CPU !!!) with a breakpoint instruction, - and update the cache so that the breakpoint instruction is really in memory and that i-cache is invalid. (or something like that) So indead you have a cache problem which is explanable solved/disapeared by steppig through with the ICE. Maybe a stupid question from me but why flushing an icache ?: r4k_flush_icache_range regards, Niels > Well I'm hoping it isn't so strange to some of you folks and you'll be > able > to tell what's going on :) > > Here's my problem: > > Using MontaVista Linux 3.1 on a Toshiba RBTx4938 board. Using YAMON, when > I > download the kernel via the debug ethernet port it runs fine. If I > download > the kernel via the Tx4938 inbuilt ethernet controller, it crashes! > > Memory checksumming and a quick manual memory dump inspection reveals that > the kernel download went perfectly ok, and the image is completely and > correctly downloaded to RAM. > > The crash is occuring inside the function r4k_flush_icache_range(). > > I tried 'flush -i' and 'flush -d' on YAMON after the download but before > the > 'go', but that didn't help. I also tried completely disabling caches and > loading/running uncached, but it gave the same error. > > Now, the final twist! Using an ICE, I set a breakpoint at the > r4k_flush_icache_range function. Then I loaded the kernel as usual, ran it > with the ICE, stepped through a few instructions inside the > r4k_flush_icache_range function and then did a 'cont'. The kernel now > booted > fine! > > If I don't set the breakpoint inside that function though, and just try to > run with the ICE the same > error (Inst fetch/Load error) occurs. > > I'm at a loss trying to figure out what's going on. I suspect it has > something to do with caches perhaps (duh!), but have no clue what! > Anybody > out there face a similar kind of a situation before? > > Thanks in advance for any help offered. > > Regards, > -Steve > > _________________________________________________________________ > MSN 9 Dial-up Internet Access helps fight spam and pop-ups – now 2 months > FREE! http://join.msn.click-url.com/go/onm00200361ave/direct/01/ > > >