From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24032 invoked by alias); 4 Sep 2008 19:28:56 -0000 Received: (qmail 24024 invoked by uid 22791); 4 Sep 2008 19:28:56 -0000 X-Spam-Check-By: sourceware.org Received: from mtagate3.de.ibm.com (HELO mtagate3.de.ibm.com) (195.212.29.152) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 04 Sep 2008 19:28:13 +0000 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate3.de.ibm.com (8.13.8/8.13.8) with ESMTP id m84JSAMY132586 for ; Thu, 4 Sep 2008 19:28:10 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m84JSAWF872578 for ; Thu, 4 Sep 2008 21:28:10 +0200 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m84JS7SG032655 for ; Thu, 4 Sep 2008 21:28:07 +0200 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.12.11) with SMTP id m84JS6uq032652; Thu, 4 Sep 2008 21:28:06 +0200 Message-Id: <200809041928.m84JS6uq032652@d12av02.megacenter.de.ibm.com> Received: by tuxmaker.boeblingen.de.ibm.com (sSMTP sendmail emulation); Thu, 4 Sep 2008 21:28:06 +0200 Subject: Re: [rfc] Displaced stepping with wrong entry point address To: drow@false.org (Daniel Jacobowitz) Date: Thu, 04 Sep 2008 19:28:00 -0000 From: "Ulrich Weigand" Cc: gdb-patches@sourceware.org, pedro@codesourcery.com In-Reply-To: <20080904121459.GB27200@caradoc.them.org> from "Daniel Jacobowitz" at Sep 04, 2008 08:14:59 AM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2008-09/txt/msg00069.txt.bz2 Daniel Jacobowitz wrote: > On Fri, Aug 22, 2008 at 07:48:46PM +0200, Ulrich Weigand wrote: > > I'm wondering whether this fix would be good for the general case too > > -- there may be situations where entry_point_address does not work > > (e.g. because the main executable file could not be loaded). The > > auxiliary vector, on targets where it is present, will probably be > > more reliable ... > > We really ought to cache this value; you'll go back and forth to the > target to read the auxv vector at every singlestep. Good point. I guess the cache would need to be reset from within a inferior_created observer? I'll give it a try ... > If SPU ever did support displaced stepping (not that this would be > terribly useful, but consider some other multi-architecture case), > would this be wrong for the SPU side code? Yes, of course -- we have different address spaces here, and we need to find a location within the address space of the current thread where to place the displaced instruction. No single address would work for both PowerPC and SPU code in a combined application. But I guess SPU could always install its own callback to handle those special cases ... (just as we install the ON_STACK dummy call location method because the AT_ENTRY method doesn't work for combined applications.) Bye, Ulrich -- Dr. Ulrich Weigand GNU Toolchain for Linux on System z and Cell BE Ulrich.Weigand@de.ibm.com