From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gdb-return-39949-listarch-gdb=sources.redhat.com@sourceware.org>
Received: (qmail 9270 invoked by alias); 13 Oct 2011 16:16:51 -0000
Received: (qmail 9247 invoked by uid 22791); 13 Oct 2011 16:16:47 -0000
X-SWARE-Spam-Status: No, hits=-2.1 required=5.0	tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,TW_GB,T_TO_NO_BRKTS_FREEMAIL
X-Spam-Check-By: sourceware.org
Received: from mail-yw0-f47.google.com (HELO mail-yw0-f47.google.com) (209.85.213.47)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 13 Oct 2011 16:16:34 +0000
Received: by ywf7 with SMTP id 7so1520971ywf.20        for <gdb@sources.redhat.com>; Thu, 13 Oct 2011 09:16:33 -0700 (PDT)
Received: by 10.42.172.194 with SMTP id o2mr1359446icz.15.1318522593104; Thu, 13 Oct 2011 09:16:33 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.42.76.65 with HTTP; Thu, 13 Oct 2011 09:16:13 -0700 (PDT)
In-Reply-To: <loom.20111012T171912-692@post.gmane.org>
References: <loom.20111012T171912-692@post.gmane.org>
From: Kevin Pouget <kevin.pouget@gmail.com>
Date: Thu, 13 Oct 2011 16:16:00 -0000
Message-ID: <CAPftXUKTyXBy3a0Sjyv5=5yZvsy=bPLs9YzdxAoeMbfMT-Jtmg@mail.gmail.com>
Subject: Re: Can gdb handle aliased memory regions ?
To: gdb@sources.redhat.com
Cc: MikeW <mw_phil@yahoo.co.uk>, Marc Titinger <marc.titinger@st.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
X-IsSubscribed: yes
Mailing-List: contact gdb-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <gdb.sourceware.org>
List-Subscribe: <mailto:gdb-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/gdb/>
List-Post: <mailto:gdb@sourceware.org>
List-Help: <mailto:gdb-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: gdb-owner@sourceware.org
X-SW-Source: 2011-10/txt/msg00074.txt.bz2

On Wed, Oct 12, 2011 at 5:35 PM, MikeW <mw_phil@yahoo.co.uk> wrote:
> Target platform: STLinux / ST Micro Connect
>
> On the target CPU, there is one region of physical memory that is accessi=
ble by
> two different mapped memory address regions: one as cached memory and one=
 as
> uncached, eg.
> =A00x8000000 (virt cached) =A0 -> 0x40000000 (phys)
> =A00xDF00000 (virt uncached) -> 0x40000000 (phys)
>
> During the kernel init, there is a code sequence which switches between c=
ached
> and uncached (to update cache registers etc) and expects the execution to
> proceed from eg. 0x80001234 to 0xDF001236.
>
> Stepping with gdb is fine until the switchover point is reached,
> whereupon gdb thinks it's lost control ('step[i]', 'next' or 'finish'
> do not return to the (gdb) prompt), but of course the ms bits of
> the PC just refer to the other region.
>
> I note gbd has support for the older technique of overlays; is there any =
way to
> tell gdb that the 0x8000... and 0xDF00... regions are actually the same p=
hysical
> memory ?
>
> Thanks.

stlinux kernel debugger maintainer cc'd