From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3tNP1V0hYpzDvrr for ; Tue, 22 Nov 2016 22:50:53 +1100 (AEDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAMBmr6J041986 for ; Tue, 22 Nov 2016 06:50:52 -0500 Received: from e19.ny.us.ibm.com (e19.ny.us.ibm.com [129.33.205.209]) by mx0a-001b2d01.pphosted.com with ESMTP id 26vkwsqyms-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 22 Nov 2016 06:50:51 -0500 Received: from localhost by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 22 Nov 2016 06:50:48 -0500 Subject: Re: [PATCH] powerpc/xmon: Fix data-breakpoint To: Michael Ellerman References: <1479806759-5409-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com> <87eg23vjds.fsf@concordia.ellerman.id.au> Cc: benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com, peterz@infradead.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, naveen.n.rao@linux.vnet.ibm.com, Ravi Bangoria From: Ravi Bangoria Date: Tue, 22 Nov 2016 17:20:38 +0530 MIME-Version: 1.0 In-Reply-To: <87eg23vjds.fsf@concordia.ellerman.id.au> Content-Type: text/plain; charset=windows-1252 Message-Id: <5834310E.1050107@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Thanks Michael, On Tuesday 22 November 2016 05:03 PM, Michael Ellerman wrote: > Ravi Bangoria writes: > >> Xmon data-breakpoint feature is broken. >> >> Whenever there is a watchpoint match occurs, hw_breakpoint_handler will >> be called by do_break via notifier chains mechanism. If watchpoint is >> registered by xmon, hw_breakpoint_handler won't find any associated >> perf_event and returns immediately with NOTIFY_STOP. Similarly, do_break >> also returns without notifying to xmon. >> >> Solve this by returning NOTIFY_DONE when hw_breakpoint_handler does not >> find any perf_event associated with matched watchpoint. > .. rather than NOTIFY_STOP, which tells the core code to continue > calling the other breakpoint handlers including the xmon one. > > Right? Yes. > Also any idea when we broke this? Hmm, not sure exactly. The code is same since it was merged in 2010 when support for hw_breakpoint was added for server processor. -Ravi > cheers >