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=-11.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A3D7FC54E8E for ; Tue, 12 May 2020 14:38:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8D3AE20722 for ; Tue, 12 May 2020 14:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730234AbgELOg7 (ORCPT ); Tue, 12 May 2020 10:36:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726300AbgELOg6 (ORCPT ); Tue, 12 May 2020 10:36:58 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A681CC061A0C; Tue, 12 May 2020 07:36:58 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jYW1e-0005lp-Ik; Tue, 12 May 2020 16:36:54 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 3224F1C02FC; Tue, 12 May 2020 16:36:54 +0200 (CEST) Date: Tue, 12 May 2020 14:36:54 -0000 From: "tip-bot2 for Will Deacon" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: locking/kcsan] kcsan: Rework data_race() so that it can be used by READ_ONCE() Cc: Will Deacon , Thomas Gleixner , "Peter Zijlstra (Intel)" , Marco Elver , x86 , LKML In-Reply-To: <20200511204150.27858-17-will@kernel.org> References: <20200511204150.27858-17-will@kernel.org> MIME-Version: 1.0 Message-ID: <158929421408.390.18401287637902669182.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the locking/kcsan branch of tip: Commit-ID: 88f1be32068d4323aa31236452352d6019a03ccc Gitweb: https://git.kernel.org/tip/88f1be32068d4323aa31236452352d6019a03ccc Author: Will Deacon AuthorDate: Mon, 11 May 2020 21:41:48 +01:00 Committer: Thomas Gleixner CommitterDate: Tue, 12 May 2020 11:04:17 +02:00 kcsan: Rework data_race() so that it can be used by READ_ONCE() Rework the data_race() macro so that it: - Accepts expressions which evaluate to a 'const' type - Attempts to discard volatile qualifiers from scalar types, avoiding pointless stack spills - Uses __kcsan_{disable,enable}_current(), allowing its use from code that is built independently from the kernel, such as the vDSO This will allow for its use by {READ,WRITE}_ONCE() in a subsequent patch. At the same time, fix-up some weird whitespace issues. Signed-off-by: Will Deacon Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Cc: Marco Elver Link: https://lkml.kernel.org/r/20200511204150.27858-17-will@kernel.org --- include/linux/compiler.h | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 548294e..cb2e3b3 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -314,14 +314,15 @@ unsigned long read_word_at_a_time(const void *addr) * This macro *does not* affect normal code generation, but is a hint * to tooling that data races here are to be ignored. */ -#define data_race(expr) \ - ({ \ - typeof(({ expr; })) __val; \ - kcsan_disable_current(); \ - __val = ({ expr; }); \ - kcsan_enable_current(); \ - __val; \ - }) +#define data_race(expr) \ +({ \ + __kcsan_disable_current(); \ + ({ \ + __unqual_scalar_typeof(({ expr; })) __v = ({ expr; }); \ + __kcsan_enable_current(); \ + __v; \ + }); \ +}) #endif /* __KERNEL__ */