Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932084AbWAEPcX (ORCPT ); Thu, 5 Jan 2006 10:32:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932078AbWAEPcX (ORCPT ); Thu, 5 Jan 2006 10:32:23 -0500 Received: from general.keba.co.at ([193.154.24.243]:56001 "EHLO helga.keba.co.at") by vger.kernel.org with ESMTP id S932082AbWAEPcW convert rfc822-to-8bit (ORCPT ); Thu, 5 Jan 2006 10:32:22 -0500 X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: Latency traces I cannot interpret (sa1100, 2.6.15-rc7-rt1) Date: Thu, 5 Jan 2006 16:32:12 +0100 Message-ID: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Latency traces I cannot interpret (sa1100, 2.6.15-rc7-rt1) Thread-Index: AcYSBKEBN1hhps4qRYakoCJS9tMVRgAB+PJg From: "kus Kusche Klaus" To: "Daniel Walker" Cc: "Ingo Molnar" , "Lee Revell" , "linux-kernel" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1721 Lines: 44 > From: Daniel Walker [mailto:dwalker@mvista.com] > On Wed, 2006-01-04 at 10:28 +0100, kus Kusche Klaus wrote: > > > From: Daniel Walker > > > Ok, yet another patch. This one uses the correct lowlevel > calls, and I > > > fixed the call ordering. > > > > Hmm, I have no deep knowledge of ARM assembler programming, > > but your patch branches to a C subroutine without setting up a > > return address in the lr register. > > > > Hence, the return in trace_irqs_... jumps to god-knows-where, > > but not back to the next instruction. > > > > As a wild guess, I replaced the "b trace_irqs_..." with > > "bl trace_irqs_...". > > Ok . > > > With this change, the kernel boots fine, but the system seems to go > > into an infinite loop as soon as the first usermode processes start. > > Most likely, my change messes up the lr register of some surrounding > > context. > > That's odd. Do you have an OOPS, or is it just a silent hang? No Oops, just a silent hang. But as far as I can tell, the macros are used in code parts where just jumps, but no calls are made (e.g. syscall entry / exit sequence) and the lr register contains data which should not be messed up by subroutine calls. -- Klaus Kusche (Software Development - Control Systems) KEBA AG Gewerbepark Urfahr, A-4041 Linz, Austria (Europe) Tel: +43 / 732 / 7090-3120 Fax: +43 / 732 / 7090-6301 E-Mail: kus@keba.com WWW: www.keba.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/