From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 75390 invoked by alias); 9 Nov 2017 21:20:15 -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 74963 invoked by uid 89); 9 Nov 2017 21:20:15 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=nowadays, H*r:sk:static., HContent-Transfer-Encoding:8bit X-HELO: mail-wm0-f48.google.com Received: from mail-wm0-f48.google.com (HELO mail-wm0-f48.google.com) (74.125.82.48) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 09 Nov 2017 21:20:14 +0000 Received: by mail-wm0-f48.google.com with SMTP id s66so4654731wmf.2 for ; Thu, 09 Nov 2017 13:20:13 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=iZYiO5Xlg7I77ng8ww8FtKR1oAXNd2L8qXdtq+741E4=; b=QhMRfKg/FyBrXS7uD35wCQfx6BtI84gVxRaujs2pPnzTX50u97wVsWLmxu1U71KWVv IhnYtEl2V8s3WHEkOHzj0uz+hF3LuxT0Z/oFNwdEbUPzd4kYx2PK11UND33sedX0YESt b6S2R0jLmG8qUVlTDCALTj4yn3RNx/E4mcdWtSj630wctF0KUNDyP70RvNoHh1IgMopu RZeFCUp7fvze9ar/rpjb4jVyqU+55awETnBFoVLqWtjRoiYBSRxgDsMTI8KS/icK+VCX FNJ80T6iEtkI2am4cLQPy+fUbUk4G9/0MmlwMxw71kS5m07oJ7UilOIzPGdIdK2Wwtw2 gyBQ== X-Gm-Message-State: AJaThX5xOhgpe7KD0oew14+kUfJO62vksMDdEmRXzzp0XMcrxTG8uG63 FdDKV5EzVdTiie96mw/QLag6sQ== X-Google-Smtp-Source: ABhQp+SgzS/Q62hEkiXt0c/JRhPmTXIut4uFBb0/CNvEo02MdVuIThfsOHoIS4lvxLz7226l4F4ARw== X-Received: by 10.80.184.10 with SMTP id j10mr2412561ede.160.1510262412035; Thu, 09 Nov 2017 13:20:12 -0800 (PST) Received: from 1170ee0b50d5 (static.42.136.251.148.clients.your-server.de. [148.251.136.42]) by smtp.gmail.com with ESMTPSA id e24sm6761390edc.9.2017.11.09.13.20.11 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 09 Nov 2017 13:20:11 -0800 (PST) Date: Thu, 09 Nov 2017 21:20:00 -0000 From: Yao Qi To: Simon Marchi Cc: Pedro Alves , gdb-patches@sourceware.org Subject: Re: [PATCH 3/3] [AArch64] Remove tag from address for watchpoint Message-ID: <20171109212009.GE318@1170ee0b50d5> References: <1509006590-9401-1-git-send-email-yao.qi@linaro.org> <1509006590-9401-4-git-send-email-yao.qi@linaro.org> <2fe62186-f1db-cf5c-f0e2-c18e35089dd9@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-IsSubscribed: yes X-SW-Source: 2017-11/txt/msg00213.txt.bz2 On 17-11-09 16:08:40, Simon Marchi wrote: > > There's gdbarch_addr_bits_remove already as well, I don't know if that has > the same goal. > Nowadays, it only used for code, # On some machines there are bits in addresses which are not really # part of the address, but are used by the kernel, the hardware, etc. # for special purposes. gdbarch_addr_bits_remove takes out any such bits so # we get a "real" address such as one would find in a symbol table. # This is used only for addresses of instructions, and even then I'm # not sure it's used in all contexts. It exists to deal with there # being a few stray bits in the PC which would mislead us, not as some # sort of generic thing to handle alignment or segmentation (it's # possible it should be in TARGET_READ_PC instead). m:CORE_ADDR:addr_bits_remove:CORE_ADDR addr:addr::core_addr_identity::0 arm and mips reuses the LSB of PC to indicate the execution state change, arm <-> thumb. gdbarch_addr_bits_remove for arm and mips clears the LSB of PC. However, this gdbarch method can't be used for data address. armv8 tagged pointer/address can be used for both code and data address. -- Yao (齐尧)