From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756522Ab2IXRTm (ORCPT ); Mon, 24 Sep 2012 13:19:42 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:61417 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755312Ab2IXRTl (ORCPT ); Mon, 24 Sep 2012 13:19:41 -0400 Date: Mon, 24 Sep 2012 18:19:35 +0100 From: Will Deacon To: Stephen Boyd Cc: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] ARM: hw_breakpoint: Clear breakpoints before enabling monitor mode Message-ID: <20120924171934.GE5522@mudshark.cambridge.arm.com> References: <1348160260-19486-1-git-send-email-sboyd@codeaurora.org> <20120920173556.GQ4654@mudshark.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120920173556.GQ4654@mudshark.cambridge.arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 20, 2012 at 06:35:56PM +0100, Will Deacon wrote: > On Thu, Sep 20, 2012 at 05:57:40PM +0100, Stephen Boyd wrote: > > +/* Determine if halting mode is enabled */ > > +static int halting_mode_enabled(void) > > +{ > > + u32 dscr; > > + > > + ARM_DBG_READ(c1, 0, dscr); > > + > > + if (WARN_ONCE(dscr & ARM_DSCR_HDBGEN, > > + "halting debug mode enabled. Unable to access hardware resources.\n")) { > > + return -EPERM; > > + } > > + return 0; > > +} > > ...it looks like debug arch 7.1 defines this bit as UNKNOWN when the OS lock > is clear, so we probably shouldn't be reading it at all. I'll pour myself a > stiff drink and start reading the debug arch docs to work out what on Earth > we should do. > > Stay tuned. Ok, I've pushed a bunch of patches to my hw-breakpoint branch (head commit 55cb726797c7). I'll post them to the list after the merge window, but please do take them for a spin if you get a chance. Will