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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8A2EC433F5 for ; Tue, 26 Apr 2022 12:10:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237226AbiDZMN0 (ORCPT ); Tue, 26 Apr 2022 08:13:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46734 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346634AbiDZMNY (ORCPT ); Tue, 26 Apr 2022 08:13:24 -0400 Received: from mail-wr1-x429.google.com (mail-wr1-x429.google.com [IPv6:2a00:1450:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E75A4140D2 for ; Tue, 26 Apr 2022 05:10:14 -0700 (PDT) Received: by mail-wr1-x429.google.com with SMTP id e24so5292929wrc.9 for ; Tue, 26 Apr 2022 05:10:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=SBTUBalrmsGV4wHuVwnt+xQyAyi2izs2hLq/5SlDTdQ=; b=IPvpTqTkcE+1lXDcXWcVswppdTfsegOwZC5FfeR8mBNzk4V1+FiUwsTpMwwIY3LqWJ eu/9DdE8exvuKdGIYWVL3uCnUfAvpGD0doUx1Y/ye0LHarcYrMqdjfrskRTeUUyIg/tm 8IlFo0SkYL4kQne3lbe/+bBnAtIj2R1irqbY9ZpaVQ180wd0pWxj+FRnn967XlchSvAk zKuvCZs/ApXVoTeaaQT8kyX4mPBQAvgXK2D64tltp/rnYzOGk1y84OjWgZ33LwrZ2WRM l5jIc3C3d+jKu0uWXxAxMJ2BgERMRXW1iK+H29hPZ2yAIk8xX7K/TLx6+Ai2LBG2ibll bUWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=SBTUBalrmsGV4wHuVwnt+xQyAyi2izs2hLq/5SlDTdQ=; b=O/9UICWvUvX+ruEgXH2l9cheBhAOwphRq8k201JKvEBz16WMn43Ds1TKtaKrmNhjEm g3uKP1eHae5lIQ4R7Dgo22nh1BcB7RzSAmrme77xIowyD+7QlfNDR18eJzPoVBt73uXo +McglqqUcXd3iUsJJdRg2YHdDIO+s4Yi8IGRKT5g2KKxTHuMSnd0dGWB9zax6PUDO18J 31M0cCJNM1Vx+EcHdVUmLAQ/dCMJR7WZn5hcuW8XMzyFwtPgd0YbG/fBqkX5K6PH+cPS l5a87mPdqEy2B7JjPoxB4w5CcH1q/e79sKyqN9reoeCr+ynjBy8xjUPOy2N/5xKttcF2 /tLA== X-Gm-Message-State: AOAM531bh5560mJ2G5alz7FC5sL+dDRYnyIy/G3fGh+WoY9UH2Pu+qRV ee12bozNN/ijsTkp7R1m07SCAXnrefvDhQ== X-Google-Smtp-Source: ABdhPJx9fs0Di5nAry45RTpJHzgxkxMgCTnkGkkrw+4C7MUY507lRNcIWaRel14QDg89AeMZOCBgXg== X-Received: by 2002:a05:6000:1a4f:b0:20a:ccdd:c70e with SMTP id t15-20020a0560001a4f00b0020accddc70emr15839931wry.444.1650975013306; Tue, 26 Apr 2022 05:10:13 -0700 (PDT) Received: from elver.google.com ([2a00:79e0:15:13:c916:9f2:ce75:976f]) by smtp.gmail.com with ESMTPSA id m4-20020a7bcb84000000b00389efb7a5b4sm13905873wmi.17.2022.04.26.05.10.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Apr 2022 05:10:12 -0700 (PDT) Date: Tue, 26 Apr 2022 14:10:06 +0200 From: Marco Elver To: Kefeng Wang Cc: catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, mark.rutland@arm.com Subject: Re: [PATCH] arm64: kcsan: Fix kcsan test_barrier fail and panic Message-ID: References: <20220426081700.1376542-1-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220426081700.1376542-1-wangkefeng.wang@huawei.com> User-Agent: Mutt/2.1.4 (2021-12-11) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 26, 2022 at 08:17AM +0000, Kefeng Wang wrote: > As "kcsan: Support detecting a subset of missing memory barriers" > introduced KCSAN_STRICT which make kcsan detects more missing memory > barrier, but arm64 don't have KCSAN instrumentation for barriers, so > the new selftest test_barrier() will fail, then panic. Thanks for fixing this - did kcsan_test module pass as well? > Let's prefix all barriers with __ on arm64, as asm-generic/barriers.h > defined the final instrumented version of these barriers, which will > fix the above issues. > > Fixes: dd03762ab608 ("arm64: Enable KCSAN") > Signed-off-by: Kefeng Wang > --- > arch/arm64/include/asm/barrier.h | 12 ++++++------ > include/asm-generic/barrier.h | 4 ++++ > 2 files changed, 10 insertions(+), 6 deletions(-) > > diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h > index 62217be36217..9760a8d4ed0a 100644 > --- a/arch/arm64/include/asm/barrier.h > +++ b/arch/arm64/include/asm/barrier.h > @@ -46,13 +46,13 @@ > #define pmr_sync() do {} while (0) > #endif > > -#define mb() dsb(sy) > -#define rmb() dsb(ld) > -#define wmb() dsb(st) > +#define __mb() dsb(sy) > +#define __rmb() dsb(ld) > +#define __wmb() dsb(st) > > -#define dma_mb() dmb(osh) > -#define dma_rmb() dmb(oshld) > -#define dma_wmb() dmb(oshst) > +#define __dma_mb() dmb(osh) > +#define __dma_rmb() dmb(oshld) > +#define __dma_wmb() dmb(oshst) > > #define io_stop_wc() dgh() > > diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h > index fd7e8fbaeef1..18863c50e9ce 100644 > --- a/include/asm-generic/barrier.h > +++ b/include/asm-generic/barrier.h > @@ -38,6 +38,10 @@ > #define wmb() do { kcsan_wmb(); __wmb(); } while (0) > #endif > > +#ifdef __dma_mb > +#define dma_mb() do { kcsan_mb(); __dma_mb(); } while (0) > +#endif > + So it looks like arm64 is the only arch that defines dma_mb(). By adding it to asm-generic, we'd almost be encouraging other architectures to add it, which I don't know we want. Documentation/memory-barriers.txt doesn't mention dma_mb() either - so perhaps dma_mb() doesn't belong in asm-generic/barrier.h, and you could only change arm64's definition of dma_mb() to add the kcsan_mb(). Preferences? Maybe arch64 maintainers have more background on why arm64 is an anomaly here.