From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31723 invoked by alias); 17 Dec 2015 08:32:01 -0000 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 Received: (qmail 31704 invoked by uid 89); 17 Dec 2015 08:32:00 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.1 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RCVD_IN_DNSWL_LOW autolearn=no version=3.3.2 spammy=gingoldadacorecom, gingold@adacore.com, Hx-languages-length:1358 X-HELO: smtp.eu.adacore.com Received: from mel.act-europe.fr (HELO smtp.eu.adacore.com) (194.98.77.210) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Thu, 17 Dec 2015 08:31:59 +0000 Received: from localhost (localhost [127.0.0.1]) by filtered-smtp.eu.adacore.com (Postfix) with ESMTP id E3D2A2EE0049; Thu, 17 Dec 2015 09:31:56 +0100 (CET) Received: from smtp.eu.adacore.com ([127.0.0.1]) by localhost (smtp.eu.adacore.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3vqBpA9Z-mxH; Thu, 17 Dec 2015 09:31:56 +0100 (CET) Received: from dhcp-guest-231.act-europe.fr (dhcp-guest-231.act-europe.fr [10.10.127.231]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.eu.adacore.com (Postfix) with ESMTPSA id D343B2EE0041; Thu, 17 Dec 2015 09:31:56 +0100 (CET) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Subject: Re: cortex-m xml register descriptions for m-system From: Tristan Gingold In-Reply-To: Date: Thu, 17 Dec 2015 08:32:00 -0000 Cc: Pedro Alves , Yao Qi , gdb-patches@sourceware.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <566F108D.1000401@redhat.com> <566F5B1A.8040703@redhat.com> To: Christopher Friedt X-IsSubscribed: yes X-SW-Source: 2015-12/txt/msg00316.txt.bz2 > On 16 Dec 2015, at 18:12, Christopher Friedt wrot= e: >=20 > On Wed, Dec 16, 2015 at 8:51 AM, Tristan Gingold wr= ote: >>=20 >>> On 15 Dec 2015, at 16:35, Christopher Friedt wr= ote: >>>=20 >>> Just so we can have consensus, please indicate what you think is the >>> best solution - Pedro, Yao, & Tristan. >>>=20 >>> Based on Tristan's feedback as well, it confirms that these registers >>> are necessary for DWARF handling. >>=20 >> Not sure about that. To my understanding, DWARF doesn=E2=80=99t need to= refer >> to psp or msp. >=20 > Wait... just yesterday you wrote: >=20 > "I do think so too. >=20 > I have just written a patch so that gdb unwinds correctly on cortex-m > exceptions, and this of course requires that gdb knows about at least > psp." >=20 > Maybe I'm confused. I presumed DWARF was involved in unwinding to some > extent, but if its purely just used for debugging, it might not > require PSP / MSP at all. No, for unwinding through HW exceptions, dwarf is not used and couldn=E2=80= =99t be use: there is no code at the return addresses. PSP is required because that can be previous stack before the exception. > In any case PSP / MSP are most definitely used in unwinding. I think that only PSP and SP are required (of course SP could be MSP). Tristan.