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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 0D018C433E0 for ; Thu, 2 Jul 2020 10:29:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E74802073E for ; Thu, 2 Jul 2020 10:29:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728425AbgGBK3G (ORCPT ); Thu, 2 Jul 2020 06:29:06 -0400 Received: from foss.arm.com ([217.140.110.172]:36076 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728376AbgGBK3F (ORCPT ); Thu, 2 Jul 2020 06:29:05 -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 C9CFDD6E; Thu, 2 Jul 2020 03:29:04 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [10.57.12.193]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A141E3F71E; Thu, 2 Jul 2020 03:29:02 -0700 (PDT) Date: Thu, 2 Jul 2020 11:28:59 +0100 From: Mark Rutland To: Marc Zyngier Cc: Will Deacon , Catalin Marinas , Daniel Lezcano , Vincenzo Frascino , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH 2/3] arm64: arch_timer: Allow an workaround descriptor to provide vdso_clock_mode Message-ID: <20200702102859.GC15391@C02TD0UTHF1T.local> References: <20200701161824.1346732-1-maz@kernel.org> <20200701161824.1346732-3-maz@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200701161824.1346732-3-maz@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 01, 2020 at 05:18:23PM +0100, Marc Zyngier wrote: > As we are about to disable the vdso for compat tasks in some circumstances, > let's allow a workaround descriptor to provide the vdso_clock_mode that > matches the platform. > > Signed-off-by: Marc Zyngier > --- > arch/arm64/include/asm/arch_timer.h | 3 +++ > drivers/clocksource/arm_arch_timer.c | 3 +++ > 2 files changed, 6 insertions(+) > > diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h > index 7ae54d7d333a..fb8dfcbf9c01 100644 > --- a/arch/arm64/include/asm/arch_timer.h > +++ b/arch/arm64/include/asm/arch_timer.h > @@ -18,6 +18,8 @@ > #include > #include > > +#include > + > #include > > #if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND) > @@ -58,6 +60,7 @@ struct arch_timer_erratum_workaround { > u64 (*read_cntvct_el0)(void); > int (*set_next_event_phys)(unsigned long, struct clock_event_device *); > int (*set_next_event_virt)(unsigned long, struct clock_event_device *); > + enum vdso_clock_mode vdso_clock_mode; > }; > > DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *, > diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c > index ecf7b7db2d05..f828835c568f 100644 > --- a/drivers/clocksource/arm_arch_timer.c > +++ b/drivers/clocksource/arm_arch_timer.c > @@ -566,6 +566,9 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa > if (wa->read_cntvct_el0) { > clocksource_counter.vdso_clock_mode = VDSO_CLOCKMODE_NONE; > vdso_default = VDSO_CLOCKMODE_NONE; > + } else { > + clocksource_counter.vdso_clock_mode = wa->vdso_clock_mode; > + vdso_default = wa->vdso_clock_mode; > } I fear that we're liable to forget to set vdso_clock_mode on new errata that don't need a read_cntvct_el0 hook, and if so we'll happen to set these to 0 (i.e. VDSO_CLOCKMODE_NONE). For now could we instead have a boolan disable_compat_vdso, with this being: | if (wa->read_cntvct_el0) { | clocksource_counter.vdso_clock_mode = VDSO_CLOCKMODE_NONE; | vdso_default = VDSO_CLOCKMODE_NONE; | } else if (wa->disable_compat_vdso) { | clocksource_counter.vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER_NOCOMPAT; | vdso_default = wa->vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER_NOCOMPAT; | } Do we need to handle the comination of a workaround seeting NONE and one setting ARCHTIMER_NOCOMPAT? Mark.