From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13760 invoked by alias); 5 Jun 2012 14:27:25 -0000 Received: (qmail 13748 invoked by uid 22791); 5 Jun 2012 14:27:25 -0000 X-SWARE-Spam-Status: No, hits=-3.4 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,KHOP_RCVD_TRUST,KHOP_THREADED,RCVD_IN_DNSWL_LOW,RCVD_IN_HOSTKARMA_YE,TW_QE X-Spam-Check-By: sourceware.org Received: from mail-ey0-f169.google.com (HELO mail-ey0-f169.google.com) (209.85.215.169) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 05 Jun 2012 14:27:12 +0000 Received: by eaan1 with SMTP id n1so1662222eaa.0 for ; Tue, 05 Jun 2012 07:27:11 -0700 (PDT) MIME-Version: 1.0 Received: by 10.14.47.3 with SMTP id s3mr7806906eeb.127.1338906430980; Tue, 05 Jun 2012 07:27:10 -0700 (PDT) Received: by 10.14.100.201 with HTTP; Tue, 5 Jun 2012 07:27:10 -0700 (PDT) In-Reply-To: References: Date: Tue, 05 Jun 2012 14:27:00 -0000 Message-ID: Subject: Re: GDB/remote: RSP `g' packet size, advice sought From: Daniel Jacobowitz To: "Maciej W. Rozycki" Cc: gdb@sourceware.org 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: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2012-06/txt/msg00030.txt.bz2 Don't take this reply too seriously, it's been a while. On Thu, May 24, 2012 at 3:17 PM, Maciej W. Rozycki wrote: > This is because the 24Kc does not support the FPU and the 24Kf does, and > hence the latter produces a longer `g' reply packet that includes the > extra FPU state. =A0However the remote backend has already shrunk its `g' > packet buffer size when talking to the 24Kc and cannot expand it back. > The only way to recover is to restart GDB from scratch that can be > annoying. > > =A0I have tracked down the cause to be the way the remote backend > initialises the `g' packet size. =A0It's only done in init_remote_state t= hat > is called once, when gdbarch data is initialized. =A0The initial size is > calculated based on the maximum number of registers supported by the > architecture: Why should those two connections have the same gdbarch? Is qemu neither returning an XML architecture description, nor a g packet size that we can use to guess an architecture with one of the registered g-packet guessing handlers? That's the actual problem - we shouldn't need to reset things within a gdbarch. Some day we should be able to connect to both of these CPUs at once. --=20 Thanks, Daniel