From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5434 invoked by alias); 8 Feb 2011 23:18:53 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 5424 invoked by uid 22791); 8 Feb 2011 23:18:52 -0000 X-SWARE-Spam-Status: No, hits=-4.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Oleg Nesterov X-Fcc: ~/Mail/utrace Cc: Jan Kratochvil , Project Archer Subject: hw_breakpoint userland interface In-Reply-To: Oleg Nesterov's message of Tuesday, 8 February 2011 21:59:53 +0100 <20110208205953.GA15932@redhat.com> References: <20110203223905.D0C77180081@magilla.sf.frob.com> <20110207211129.GA23277@host1.dyn.jankratochvil.net> <20110208015844.B994A1814A4@magilla.sf.frob.com> <20110208205953.GA15932@redhat.com> Message-Id: <20110208231846.EC8BA1814AA@magilla.sf.frob.com> Date: Tue, 08 Feb 2011 23:18:00 -0000 X-SW-Source: 2011-q1/txt/msg00038.txt.bz2 There are indeed many things to be figured out about a userland interface for hw_breakpoint. It's certainly quite possible that something entirely separate from ptrace is the right approach for that. I haven't given it any thought, really. It should be worked out with Jan and other GDB folks as well as whoever in the kernel sphere cares about hw_breakpoint stuff. It might be a ptrace-based interface, or it might be a separate interface that interacts with ptrace (perhaps just generating some new PTRACE_EVENT_* type for its stops). If the hw_breakpoint stuff is well-integrated with perf event stuff, then perhaps a good approach involves a more general-purpose interlock between ptrace and perf event stuff. That is, a way for GDB to make use of all that stuff in a somewhat clean fashion for its case, that being of unprivileged all-userland control that ties into ptrace stops somehow. Thanks, Roland