From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vs1-xe2f.google.com (mail-vs1-xe2f.google.com [IPv6:2607:f8b0:4864:20::e2f]) by sourceware.org (Postfix) with ESMTPS id DF55D3870855 for ; Wed, 10 Jun 2020 20:34:28 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org DF55D3870855 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=sifive.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=jimw@sifive.com Received: by mail-vs1-xe2f.google.com with SMTP id g129so2108487vsc.4 for ; Wed, 10 Jun 2020 13:34:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=usDYAYiNDxnWTKGo1AMuh14/BiqoTX/tBWkUhiDo1YQ=; b=iwdU02RinCslDCs38h/nYt01t6zdU5FxeQtGLakJUipV4sg2rbr2bPORR+odFewVAt UDz/82r+LwPBk6s6F3vrscZvAMlnli7yDq2ADAE2g1p7+AJKVClolVJWcelxGMAZFUU2 dkWzXQ37PPTIzIL6GBqJiV8p4An4RK+QrGfY2rZkZ9zvMD9tKXk7SO9lTvKl0NE9zjvB hRO12R46IVBDb19b/DRzvepRnEFd0a37DZ5TfOvme12U1xgU1d1r5L0o8ABYjslXXOYh 4QZxS24WNeRRYxSz/XHVXlP/W6N45EEV4XetzIx6jA9GSAY4AXgWJhMXHfdy328avhx8 4r5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=usDYAYiNDxnWTKGo1AMuh14/BiqoTX/tBWkUhiDo1YQ=; b=VYgcLNpaM0fTp9SfoCLzwt3eZpTGATnmQTjWp3H/kUSjXNctQeECNbsJffhdwT17k4 za1wgDsN22VAfGuIBgejUnW9Y33gOoKXZlNFYgsTknqsCB8FMNQjzUnnowYn5kISUx4c VHhv7wWahahRLsvfgg5X5ZLj9e/Bv5IYIMleVo3SToT0lS6Hn4i4eMJr9csexCWBBk8Q zE9ZFRvCGTJZ8fYa7pbT35dSFBudQIxFaEYO6gBX1XfcRhuDCIHhmgHYrCgCfaPBwHi1 y/8JUZQefaUp6hhzjuYsHOtdrNc9hVXrYNiRnVjgqbNRnIxUT0ZiS73iuCAn2KfPcMUi A4GQ== X-Gm-Message-State: AOAM532iAKwcl0sRemuxaTnc6ht9PE+KcCLhGvog49WujHM7SNvrU1Ik hspzuM89HIQ50Ytt9n/wUpo+gertKgd63TdVm3kVOw== X-Google-Smtp-Source: ABdhPJw5Mp1G/DwX6NMIZM3lclvQ28CkKLc4FOEmP9Ecsuty0V2FLQFkBKL1QAgC0QMHFoN+5T57UG/p6gZI8L9fw3w= X-Received: by 2002:a05:6102:22ec:: with SMTP id b12mr4183034vsh.138.1591821268254; Wed, 10 Jun 2020 13:34:28 -0700 (PDT) MIME-Version: 1.0 References: <1584007257-14466-1-git-send-email-nelson.chu@sifive.com> <87r1upefg8.fsf@tromey.com> <20200609173040.GE2737@embecosm.com> <87pna855a8.fsf@tromey.com> In-Reply-To: <87pna855a8.fsf@tromey.com> From: Jim Wilson Date: Wed, 10 Jun 2020 13:34:17 -0700 Message-ID: Subject: Re: [RFC] gdb/riscv: Improved register alias name creation To: Tom Tromey Cc: Andrew Burgess , gdb-patches@sourceware.org Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3.3 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, URIBL_CSS, URIBL_CSS_A autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Jun 2020 20:34:30 -0000 On Tue, Jun 9, 2020 at 1:54 PM Tom Tromey wrote: > (gdb) call debug.trace (me, "You") > Could not fetch register "mucounteren"; remote failure reply 'E14' mucounteren is one of those inconvenient registers that got dropped, and then its address got reused for a different unrelated register in a later priv spec version. The easy solution is on the qemu side to stop using this register, but that doesn't help anyone using a qemu release. On the gdb side we would need to make gdb priv spec version aware, or else lie to gdb and pretend that two unrelated registers in different priv spec versions are the same register and hope that doesn't cause trouble. This priv spec version problem goes away once we drop all 1.9 and 1.9.1 support, because the compatibility problems only exist between versions before 1.10 and versions 1.10 and later. I've been told that there won't be any more compatibility breaks from 1.10 and later. qemu never had 1.9 support, and has already proposed dropping 1.9.1 support on mainline, but of course older qemu releases have the 1.9.1 support. binutils still has 1.9 and 1.9.1 support, but I've suggested to Nelson that he should drop the 1.9 support because I'm not aware of anyone using it. Jim