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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C4E79C00454 for ; Tue, 10 Dec 2019 21:41:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9292420828 for ; Tue, 10 Dec 2019 21:41:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576014115; bh=qoWIB+0WSAHa/3SwzS6I1z52KR/Wh/ZPFYeXYzN9PqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sqFe+aurQ+elPlyZJi+K7qqS4UjHJ/tX/Z5LSb0m48K/N0yWVBQSp1WZxa77/lVve LnfmNJSLHvy/KsilJ8HrgcioD6OBBvzwTXNmS7jwGFNVBA6j/9+BCUh2vSyAtc7WIL H7/f3dkN9HWUlMGNkU2/4Ij/KylUKHEMe+Aw9WeU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728114AbfLJVly (ORCPT ); Tue, 10 Dec 2019 16:41:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:39050 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729947AbfLJVeJ (ORCPT ); Tue, 10 Dec 2019 16:34:09 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 758592465C; Tue, 10 Dec 2019 21:34:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576013649; bh=qoWIB+0WSAHa/3SwzS6I1z52KR/Wh/ZPFYeXYzN9PqQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sLL1mPeBAoXoI926gXMbkYvbOWv2jUF5xsLpodLPJ0MlveYWb58Fl6BEAljXq4ay6 9Eduj++BiYLMcnNYlPWOvbpAeWyHoBwj5oAtVWLB/yvrMVOyo+D1cnbNKYD4i0bsgJ Knqyk+e+w3iU49kGUs9r7c5phhsNl+p0M+mBdNws= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Heiko Carstens , Vasily Gorbik , Sasha Levin , linux-s390@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 088/177] s390/time: ensure get_clock_monotonic() returns monotonic values Date: Tue, 10 Dec 2019 16:30:52 -0500 Message-Id: <20191210213221.11921-88-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191210213221.11921-1-sashal@kernel.org> References: <20191210213221.11921-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Heiko Carstens [ Upstream commit 011620688a71f2f1fe9901dbc2479a7c01053196 ] The current implementation of get_clock_monotonic() leaves it up to the caller to call the function with preemption disabled. The only core kernel caller (sched_clock) however does not disable preemption. In order to make sure that all callers of this function see monotonic values handle disabling preemption within the function itself. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik Signed-off-by: Sasha Levin --- arch/s390/include/asm/timex.h | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index 64539c221672b..0f12a3f912820 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -10,8 +10,9 @@ #ifndef _ASM_S390_TIMEX_H #define _ASM_S390_TIMEX_H -#include +#include #include +#include /* The value of the TOD clock for 1.1.1970. */ #define TOD_UNIX_EPOCH 0x7d91048bca000000ULL @@ -186,15 +187,18 @@ extern unsigned char tod_clock_base[16] __aligned(8); /** * get_clock_monotonic - returns current time in clock rate units * - * The caller must ensure that preemption is disabled. * The clock and tod_clock_base get changed via stop_machine. - * Therefore preemption must be disabled when calling this - * function, otherwise the returned value is not guaranteed to - * be monotonic. + * Therefore preemption must be disabled, otherwise the returned + * value is not guaranteed to be monotonic. */ static inline unsigned long long get_tod_clock_monotonic(void) { - return get_tod_clock() - *(unsigned long long *) &tod_clock_base[1]; + unsigned long long tod; + + preempt_disable(); + tod = get_tod_clock() - *(unsigned long long *) &tod_clock_base[1]; + preempt_enable(); + return tod; } /** -- 2.20.1