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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56C1FC433F5 for ; Sun, 17 Oct 2021 12:47:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CAE660E54 for ; Sun, 17 Oct 2021 12:47:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343690AbhJQMt1 (ORCPT ); Sun, 17 Oct 2021 08:49:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:39530 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343597AbhJQMtA (ORCPT ); Sun, 17 Oct 2021 08:49:00 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EB13960F48; Sun, 17 Oct 2021 12:46:50 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mc5V5-00HKfO-Po; Sun, 17 Oct 2021 13:42:51 +0100 From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Daniel Lezcano , Will Deacon Cc: Mark Rutland , Thomas Gleixner , Peter Shier , Raghavendra Rao Ananta , Ricardo Koller , Oliver Upton , Catalin Marinas , Linus Walleij , kernel-team@android.com Subject: [PATCH v4 13/17] clocksource/arch_arm_timer: Move workaround synchronisation around Date: Sun, 17 Oct 2021 13:42:21 +0100 Message-Id: <20211017124225.3018098-14-maz@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211017124225.3018098-1-maz@kernel.org> References: <20211017124225.3018098-1-maz@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, daniel.lezcano@linaro.org, will@kernel.org, mark.rutland@arm.com, tglx@linutronix.de, pshier@google.com, rananta@google.com, ricarkol@google.com, oupton@google.com, catalin.marinas@arm.com, linus.walleij@linaro.org, kernel-team@android.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We currently handle synchronisation when workarounds are enabled by having an ISB in the __arch_counter_get_cnt?ct_stable() helpers. While this works, this prevents us from relaxing this synchronisation. Instead, move it closer to the point where the synchronisation is actually needed. Further patches will subsequently relax this. Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/arch_timer.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index b8000ef71a2c..519ac1f7f859 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -32,7 +32,7 @@ ({ \ const struct arch_timer_erratum_workaround *__wa; \ __wa = __this_cpu_read(timer_unstable_counter_workaround); \ - (__wa && __wa->h) ? __wa->h : arch_timer_##h; \ + (__wa && __wa->h) ? ({ isb(); __wa->h;}) : arch_timer_##h; \ }) #else @@ -64,11 +64,13 @@ DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *, static inline notrace u64 arch_timer_read_cntpct_el0(void) { + isb(); return read_sysreg(cntpct_el0); } static inline notrace u64 arch_timer_read_cntvct_el0(void) { + isb(); return read_sysreg(cntvct_el0); } @@ -163,7 +165,6 @@ static __always_inline u64 __arch_counter_get_cntpct_stable(void) { u64 cnt; - isb(); cnt = arch_timer_reg_read_stable(cntpct_el0); arch_counter_enforce_ordering(cnt); return cnt; @@ -183,7 +184,6 @@ static __always_inline u64 __arch_counter_get_cntvct_stable(void) { u64 cnt; - isb(); cnt = arch_timer_reg_read_stable(cntvct_el0); arch_counter_enforce_ordering(cnt); return cnt; -- 2.30.2