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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 F1CADC4338F for ; Mon, 9 Aug 2021 11:15:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D92E4610CB for ; Mon, 9 Aug 2021 11:15:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234992AbhHILPp (ORCPT ); Mon, 9 Aug 2021 07:15:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234996AbhHILPn (ORCPT ); Mon, 9 Aug 2021 07:15:43 -0400 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1ED1EC061796 for ; Mon, 9 Aug 2021 04:15:23 -0700 (PDT) Received: by mail-pj1-x102c.google.com with SMTP id lw7-20020a17090b1807b029017881cc80b7so7801119pjb.3 for ; Mon, 09 Aug 2021 04:15:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=FNKiiIhfoxwyjjlrmMVPD0DKnFNw0oyY5Z/6cuWikiM=; b=q50IRsTzpC659Hj0lYLMLuS575e4kkbjR6P5w0qCT/vBGQXrlGA9mAYEtRCevdNVXO IW/7JO5iQ6ifmD/sqFUOzDnoRbGD+VdR8F9i9UVppdU6oz0LpeG0pOARX3Aiu+7ztsRv i0pimaiGSBM/WBcgk4+OcFqgtApCNqfCIJbE6y5PqahgUnf3DNMRxSgwPexiMsISE622 O2K8sX9HYLU+Q4imWk7EBYkQyOXi9EGtA26f9B5G+28WkP36Htn+u/BdffzD8vT0RuKI Ibg7+7DUA/bGCv/buIEyfL8IXjAZ08XKDaFWzN8Jrg2e3RuHJO8zd2LGIicd8ceinsdz 4SXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=FNKiiIhfoxwyjjlrmMVPD0DKnFNw0oyY5Z/6cuWikiM=; b=OTxJGY7hm3YIynHXYlnC9hYJeMnLGWSbc2ebgYeRZcZDZtrP+VgPL5JIvXxftFQdvk KycdJ57knJ1FXytBiFNGSz2fUPk7qhzEbW0B8NAfrKHlP0/1vOIFc2yVI5PGs2ih6xvA yI4Y+EeDUFmHDuUT6LLIXzMyaCpkfCqNmEdZdxXKZ1ccX7aw2mF8FlS9g6TwvriwMoRy yeRZFvoQjFTjn0Iud/kMsva9GxcDAnPir80y9C3sTa3Qy3MjW6LsXAVqkbkYeCAa6wAz KOlIlHFQM0uWx/BW9fOWU2duUDTjAxZiaPel23z8QfcAurUAVERtcs8Xu2C9Rflez8WJ 4icQ== X-Gm-Message-State: AOAM5304rlYt2PPZiKL2XQiSa6/TsGaY33taj/R57iqt2ikm1ZufZlHB wdRhgi3OLip71KJAH5XTuXHoFQ== X-Google-Smtp-Source: ABdhPJwEQt4wx3EDVsKEI4XgBS5gyLZRktaFVxothL5bIu5lfUl2KRqYEoPglvPGKDc0UiH6GxMDdQ== X-Received: by 2002:a17:903:1243:b029:107:eca4:d5bf with SMTP id u3-20020a1709031243b0290107eca4d5bfmr1421457plh.15.1628507722603; Mon, 09 Aug 2021 04:15:22 -0700 (PDT) Received: from localhost ([210.0.159.74]) by smtp.gmail.com with ESMTPSA id w15sm17904203pjc.45.2021.08.09.04.15.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Aug 2021 04:15:22 -0700 (PDT) From: Leo Yan To: Arnaldo Carvalho de Melo , Peter Zijlstra , Adrian Hunter , Ingo Molnar , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Thomas Gleixner , Borislav Petkov , "H. Peter Anvin" , Mathieu Poirier , Suzuki K Poulose , Mike Leach , Michael Petlan , "Frank Ch. Eigler" , Song Liu , x86@kernel.org, =?UTF-8?q?Daniel=20D=C3=ADaz?= , Andrii Nakryiko , Alexei Starovoitov , Sedat Dilek , Andi Kleen , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, coresight@lists.linaro.org Cc: Leo Yan Subject: [PATCH v5 2/9] coresight: tmc-etr: Add barrier after updating AUX ring buffer Date: Mon, 9 Aug 2021 19:14:00 +0800 Message-Id: <20210809111407.596077-3-leo.yan@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210809111407.596077-1-leo.yan@linaro.org> References: <20210809111407.596077-1-leo.yan@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org Since a memory barrier is required between AUX trace data store and aux_head store, and the AUX trace data is filled with memcpy(), it's sufficient to use smp_wmb() so can ensure the trace data is visible prior to updating aux_head. Signed-off-by: Leo Yan Reviewed-by: Suzuki K Poulose --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index acdb59e0e661..13fd1fc730ed 100644 --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c @@ -1563,6 +1563,14 @@ tmc_update_etr_buffer(struct coresight_device *csdev, */ if (etr_perf->snapshot) handle->head += size; + + /* + * Ensure that the AUX trace data is visible before the aux_head + * is updated via perf_aux_output_end(), as expected by the + * perf ring buffer. + */ + smp_wmb(); + out: /* * Don't set the TRUNCATED flag in snapshot mode because 1) the -- 2.25.1