Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754790Ab3HWJ5R (ORCPT ); Fri, 23 Aug 2013 05:57:17 -0400 Received: from service87.mimecast.com ([91.220.42.44]:41717 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753600Ab3HWJ5Q convert rfc822-to-8bit (ORCPT ); Fri, 23 Aug 2013 05:57:16 -0400 Message-ID: <5217321B.6060306@arm.com> Date: Fri, 23 Aug 2013 10:57:47 +0100 From: Sudeep KarkadaNagesha User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 MIME-Version: 1.0 To: Catalin Marinas CC: Sudeep KarkadaNagesha , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Lorenzo Pieralisi , Will Deacon , Thomas Gleixner , Daniel Lezcano Subject: Re: [PATCH v3 0/6] ARM/ARM64 architected timer updates References: <1374492082-13686-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1376414984-14182-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <5213A40C.6060509@arm.com> <20130823092610.GB20186@darko.cambridge.arm.com> In-Reply-To: <20130823092610.GB20186@darko.cambridge.arm.com> X-OriginalArrivalTime: 23 Aug 2013 09:57:14.0035 (UTC) FILETIME=[24955030:01CE9FE7] X-MC-Unique: 113082310571404601 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1845 Lines: 41 On 23/08/13 10:26, Catalin Marinas wrote: > On Tue, Aug 20, 2013 at 06:14:52PM +0100, Sudeep KarkadaNagesha wrote: >> On 13/08/13 18:29, Sudeep KarkadaNagesha wrote: >>> From: Sudeep KarkadaNagesha >>> >>> This patch series adds support to configure the rate and enable the >>> event stream for architected timer. The event streams can be used to >>> impose a timeout on a WFE, to safeguard against any programming error >>> in case an expected event is not generated or even to implement >>> wfe-based timeouts for userspace locking implementations. >>> >>> Since the timer control register is reset to zero on warm boot, CPU >>> PM notifier is added to re-initialize it. >>> >>> Changes v2->v3: >>> 1. Moved ARM and ARM64 changes into separate patches >>> 2. Added native hwcaps definations(ARM/ARM64) and compat-specific >>> definitions(ARM64) to the users for the event stream feature. >> >> Can you review this version of the series ? > > I think the series is OK with the follow-up comments addressed. Could > you please post a v4 to make sure I haven't missed anything? > > Another comment I have is whether we should make this feature > configurable. The reason is mainly hardware validation: if some CPU > implementation messes the event generation (and on ARMv8 it's a bit more > complex as this is tied to the exclusive monitor) we risk not detecting > it because of the event stream. Yes that seems reasonable. I assume we can enable it by default and we need to disable it for hardware validation. Let me know if think otherwise. Regards, Sudeep -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/