From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF7F7C4CECD for ; Tue, 17 Sep 2019 17:10:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B526320665 for ; Tue, 17 Sep 2019 17:10:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568740233; bh=ocxnVjcPJtjnZ9vupxOgSmNpnZd8pTHz6J/W+xLzurU=; h=Subject:To:Cc:References:From:Date:In-Reply-To:List-ID:From; b=RHeycYvSmrlpDZgIOd524EIKsza3Dr1yX+2ZwRlUjK8f15teIyrarKMXffBvBGBzd VTGvFUHVUlhy+qLlnxwSlMcYwKGN7i/Wq5A2yNqzV5dvyYWsw34Okc1XBVD+iJSN98 ms+EcG4tFdasWFnLx6FtCyyoRiykyd9EThidG/6I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727444AbfIQRKa (ORCPT ); Tue, 17 Sep 2019 13:10:30 -0400 Received: from foss.arm.com ([217.140.110.172]:59086 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725811AbfIQRKa (ORCPT ); Tue, 17 Sep 2019 13:10:30 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8468328; Tue, 17 Sep 2019 10:10:29 -0700 (PDT) Received: from [10.1.197.61] (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D136B3F575; Tue, 17 Sep 2019 10:10:27 -0700 (PDT) Subject: Re: [PATCH 3/6] Timer: expose monotonic clock and counter value To: Jianyong Wu , netdev@vger.kernel.org, pbonzini@redhat.com, sean.j.christopherson@intel.com, richardcochran@gmail.com, Mark.Rutland@arm.com, Will.Deacon@arm.com, suzuki.poulose@arm.com Cc: linux-kernel@vger.kernel.org, Steve.Capper@arm.com, Kaly.Xin@arm.com, justin.he@arm.com, nd@arm.com, linux-arm-kernel@lists.infradead.org References: <20190917112430.45680-1-jianyong.wu@arm.com> <20190917112430.45680-4-jianyong.wu@arm.com> From: Marc Zyngier Organization: Approximate Message-ID: Date: Tue, 17 Sep 2019 18:10:26 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20190917112430.45680-4-jianyong.wu@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 17/09/2019 12:24, Jianyong Wu wrote: > A number of PTP drivers (such as ptp-kvm) are assuming what the > current clock source is, which could lead to interesting effects on > systems where the clocksource can change depending on external events. > > For this purpose, add a new API that retrives both the current > monotonic clock as well as its counter value. > > Signed-off-by: Marc Zyngier > Signed-off-by: Jianyong Wu There must be something wrong with the way you've taken this patch in your tree. My authorship is gone (not that I deeply care about it, but it is good practice to keep attributions), and the subject line has been rewritten. I'd appreciate it if you could fix this in a future revision of this series. For reference, the original patch is here[1]. > --- > include/linux/timekeeping.h | 3 +++ > kernel/time/timekeeping.c | 13 +++++++++++++ > 2 files changed, 16 insertions(+) > > diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h > index a8ab0f143ac4..a5389adaa8bc 100644 > --- a/include/linux/timekeeping.h > +++ b/include/linux/timekeeping.h > @@ -247,6 +247,9 @@ extern int get_device_system_crosststamp( > struct system_time_snapshot *history, > struct system_device_crosststamp *xtstamp); > > +/* Obtain current monotonic clock and its counter value */ > +extern void get_current_counterval(struct system_counterval_t *sc); > + > /* > * Simultaneously snapshot realtime and monotonic raw clocks > */ > diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c > index 44b726bab4bd..07a0969625b1 100644 > --- a/kernel/time/timekeeping.c > +++ b/kernel/time/timekeeping.c > @@ -1098,6 +1098,19 @@ static bool cycle_between(u64 before, u64 test, u64 after) > return false; > } > > +/** > + * get_current_counterval - Snapshot the current clocksource and counter value > + * @sc: Pointer to a struct containing the current clocksource and its value > + */ > +void get_current_counterval(struct system_counterval_t *sc) > +{ > + struct timekeeper *tk = &tk_core.timekeeper; > + > + sc->cs = READ_ONCE(tk->tkr_mono.clock); > + sc->cycles = sc->cs->read(sc->cs); > +} > +EXPORT_SYMBOL_GPL(get_current_counterval); This export wasn't in my original patch. I guess you need it because your ptp driver builds as a module? It'd be good to mention it in the commit log. > + > /** > * get_device_system_crosststamp - Synchronously capture system/device timestamp > * @get_time_fn: Callback to get simultaneous device time and > Thanks, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=timer/counterval&id=a6e8abce025691b6a55e1c195878d7f76bfeb9d1 -- Jazz is not dead, it just smells funny...