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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 6CF26C2D0CE for ; Sun, 29 Dec 2019 17:40:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 45671206A4 for ; Sun, 29 Dec 2019 17:40:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577641233; bh=LzEFEz/rwAarUMRtuzFxTzAa7OZ9EE8KIOv5dBfUEak=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=t8NVnWjgyBMdJaLbf3fuQ6lLVEBaeBMgcf5g5AS3jdf6yu2aVwUIRkVscKODkZe6d AgAYKsR6MqYAeOj8kCQWBvJYlmiR1cIbDOb3kbVzjN82ItOEESJMOMLWbcBhh5ywr5 IdVtrhpMPtUp/0KTJKjrIvgIUH+rXmgUz5PyDlCo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730152AbfL2Rkc (ORCPT ); Sun, 29 Dec 2019 12:40:32 -0500 Received: from mail.kernel.org ([198.145.29.99]:59300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729191AbfL2Rbm (ORCPT ); Sun, 29 Dec 2019 12:31:42 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 3A0A2207FD; Sun, 29 Dec 2019 17:31:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577640701; bh=LzEFEz/rwAarUMRtuzFxTzAa7OZ9EE8KIOv5dBfUEak=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=at/2k6dsbwg58ZVL/rEkj0Evo9ECQUhVFHBMBx0CpNNOJgwWKmQ3dMynHY8G2ErVd 3QpVGuncIu46KLt77QfasAaTwJalLjsTzKIbFMUc2YxpGNFdIDNM/dQHpqbWQC8CKR nkSH7/K1gSoe+DhU9mHc9LXisThqrPI5T0HH/EgE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Sasha Levin Subject: [PATCH 4.19 104/219] s390/time: ensure get_clock_monotonic() returns monotonic values Date: Sun, 29 Dec 2019 18:18:26 +0100 Message-Id: <20191229162524.319834383@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191229162508.458551679@linuxfoundation.org> References: <20191229162508.458551679@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 64539c221672..0f12a3f91282 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