From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5125 invoked by alias); 19 Dec 2014 11:18:41 -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 5115 invoked by uid 89); 19 Dec 2014 11:18:40 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Fri, 19 Dec 2014 11:18:39 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sBJBIbJt018364 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 19 Dec 2014 06:18:37 -0500 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id sBJBIZQn001121; Fri, 19 Dec 2014 06:18:36 -0500 Message-ID: <5494098B.7080002@redhat.com> Date: Fri, 19 Dec 2014 11:18:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Yao Qi CC: gdb-patches@sourceware.org Subject: Re: [PATCH] MIPS: Handle the DSP registers for bare metal References: <1418909149-29929-1-git-send-email-yao@codesourcery.com> <54930ED2.1080806@redhat.com> <87r3vwqooq.fsf@codesourcery.com> In-Reply-To: <87r3vwqooq.fsf@codesourcery.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-12/txt/msg00574.txt.bz2 On 12/19/2014 03:54 AM, Yao Qi wrote: > Pedro Alves writes: > >> Took me a bit to grok this, but this is adding slack for ACXn, right? > > Sorry, what do you mean by "slack" here? Is it "gap" or something else? Yes, "gap". > The offsets of DSP registers are different on linux and bare metal, so > this patch gives the correct offset or layout to them. The proper solution for this issue is to decouple GDB's internal register numbers from the target's g/G packet layout, which is exactly what happens when you have a description -- GDB uses the offsets found in the target description. And you're touching code that is parsing a description, so the real issue should be in the target description. > >> But it seems like nothing in GDB knows about those ACX registers. I >> guess I'm being dense, but why is this patch needed then? They should still >> be accessible to the user even without this change, right? Assuming the >> description is including them. > > We want the number of these registers are fixed, and these fixed numbers > will be used in a follow-up patch about dynamic registers discovery > (which is about reading available config registers and parsing bits in them) > MIPS architecture defines 50+ subset of optional CP0 registers, so the > number of variants is too high to make current static register > description approach useless. I think this should be discussed further. Thanks, Pedro Alves