From patchwork Mon Sep 28 08:32:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhou Wang X-Patchwork-Id: 11803151 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C924B112C for ; Mon, 28 Sep 2020 08:37:28 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 83354207E8 for ; Mon, 28 Sep 2020 08:37:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="eXVoL0D2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83354207E8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=hisilicon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To:From: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=9eXFMN4l/NRET60XFjDaBoGi6DPbFeAVPGZLBMHgfVg=; b=eXVoL0D2iXOThP80tuzN8uSBuU IWMFk4HW1vo6P8Ca5MQZctEH0OnOIlx6Pn/vlbsUDweWGR75dcpRF1h5OUf1cbDwZgw2eJpK3/JgV wtOIwn/6d6cxgl9HmSmEVF7NjBo8o3OD1AbttT370rpinXu5UAGu4JPhBCrhvuKAu3yBNInF7gM70 zG8impwFVlixt0vVVQriesPdVtLpRAqd8pieie5PF76z2qL/G6m3As9tP6pMo6ezmdPpiUe/4W7QG v+A5Er8D+OUsn1OLB6J/m8gqJAPRjmlj03YF2wdedbw+QS+jTF4C395nuBMISxqEn7RRvb9a5Fgau Q9PChIsg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kMoen-0006CA-8h; Mon, 28 Sep 2020 08:37:13 +0000 Received: from szxga04-in.huawei.com ([45.249.212.190] helo=huawei.com) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kMoeB-0005qV-O8 for linux-arm-kernel@lists.infradead.org; Mon, 28 Sep 2020 08:36:40 +0000 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 15269537B3B1197B30D3; Mon, 28 Sep 2020 16:36:21 +0800 (CST) Received: from localhost.localdomain (10.69.192.58) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.487.0; Mon, 28 Sep 2020 16:36:14 +0800 From: Zhou Wang To: Will Deacon , Robin Murphy , "Joerg Roedel" , Jean-Philippe Brucker Subject: [PATCH] iommu/arm-smmu-v3: Add rmb after reading event queue prod_reg Date: Mon, 28 Sep 2020 16:32:02 +0800 Message-ID: <1601281922-117296-1-git-send-email-wangzhou1@hisilicon.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200928_043636_572176_A363C682 X-CRM114-Status: GOOD ( 11.29 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [45.249.212.190 listed in list.dnswl.org] 0.0 RCVD_IN_MSPIKE_H4 RBL: Very Good reputation (+4) [45.249.212.190 listed in wl.mailspike.net] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 SPF_HELO_PASS SPF: HELO matches SPF record 0.0 RCVD_IN_MSPIKE_WL Mailspike good senders X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zhou Wang , iommu@lists.linux-foundation.org, linuxarm@huawei.com, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org In arm_smmu_evtq_thread, reading event queue is from consumer pointer, which has no address dependency on producer pointer, prog_reg(MMIO) and event queue memory(Normal memory) can disorder. So the load for event queue can be done before the load of prod_reg, then perhaps wrong event entry value will be got. Add rmb to make sure to get correct event queue entry value. Signed-off-by: Zhou Wang --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c index c192544..93c9077 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -819,6 +819,9 @@ static int queue_sync_prod_in(struct arm_smmu_queue *q) int ret = 0; u32 prod = readl_relaxed(q->prod_reg); + /* Ensure that reading event queue is after reading prod_reg */ + rmb(); + if (Q_OVF(prod) != Q_OVF(q->llq.prod)) ret = -EOVERFLOW;