From patchwork Mon Dec 20 14:34:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 526560 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 C4E6BC433FE for ; Mon, 20 Dec 2021 14:38:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234046AbhLTOiC (ORCPT ); Mon, 20 Dec 2021 09:38:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59504 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234230AbhLTOhg (ORCPT ); Mon, 20 Dec 2021 09:37:36 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6D8CC06175F; Mon, 20 Dec 2021 06:37:35 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 743EAB80EEB; Mon, 20 Dec 2021 14:37:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABD9AC36AE9; Mon, 20 Dec 2021 14:37:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640011053; bh=bYjsEbs2ra7c8/1V2IPQc0aLtXClxuEYL7783b++02A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rEIe1qCVpNQHuKXD8PQ9GW+m/hrEG7ru6zjnhmrGmMDyNJuTVTmAHozWYIY0f0oB1 LlpofKGnkg9Fan6whsMlkvc+jtZCUEufjJudeU253Uzs1/u0uGrfAJZAz+RqrcWwfu iXo+I6ZWW+ll6pZmN4LAeIbTOSKqhEIwSG3g3Gnw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Florian Fainelli , Jakub Kicinski Subject: [PATCH 4.9 19/31] net: systemport: Add global locking for descriptor lifecycle Date: Mon, 20 Dec 2021 15:34:19 +0100 Message-Id: <20211220143020.593276120@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211220143019.974513085@linuxfoundation.org> References: <20211220143019.974513085@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Florian Fainelli commit 8b8e6e782456f1ce02a7ae914bbd5b1053f0b034 upstream. The descriptor list is a shared resource across all of the transmit queues, and the locking mechanism used today only protects concurrency across a given transmit queue between the transmit and reclaiming. This creates an opportunity for the SYSTEMPORT hardware to work on corrupted descriptors if we have multiple producers at once which is the case when using multiple transmit queues. This was particularly noticeable when using multiple flows/transmit queues and it showed up in interesting ways in that UDP packets would get a correct UDP header checksum being calculated over an incorrect packet length. Similarly TCP packets would get an equally correct checksum computed by the hardware over an incorrect packet length. The SYSTEMPORT hardware maintains an internal descriptor list that it re-arranges when the driver produces a new descriptor anytime it writes to the WRITE_PORT_{HI,LO} registers, there is however some delay in the hardware to re-organize its descriptors and it is possible that concurrent TX queues eventually break this internal allocation scheme to the point where the length/status part of the descriptor gets used for an incorrect data buffer. The fix is to impose a global serialization for all TX queues in the short section where we are writing to the WRITE_PORT_{HI,LO} registers which solves the corruption even with multiple concurrent TX queues being used. Fixes: 80105befdb4b ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver") Signed-off-by: Florian Fainelli Link: https://lore.kernel.org/r/20211215202450.4086240-1-f.fainelli@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/broadcom/bcmsysport.c | 5 +++++ drivers/net/ethernet/broadcom/bcmsysport.h | 1 + 2 files changed, 6 insertions(+) --- a/drivers/net/ethernet/broadcom/bcmsysport.c +++ b/drivers/net/ethernet/broadcom/bcmsysport.c @@ -90,9 +90,13 @@ static inline void tdma_port_write_desc_ struct dma_desc *desc, unsigned int port) { + unsigned long desc_flags; + /* Ports are latched, so write upper address first */ + spin_lock_irqsave(&priv->desc_lock, desc_flags); tdma_writel(priv, desc->addr_status_len, TDMA_WRITE_PORT_HI(port)); tdma_writel(priv, desc->addr_lo, TDMA_WRITE_PORT_LO(port)); + spin_unlock_irqrestore(&priv->desc_lock, desc_flags); } /* Ethtool operations */ @@ -1587,6 +1591,7 @@ static int bcm_sysport_open(struct net_d } /* Initialize both hardware and software ring */ + spin_lock_init(&priv->desc_lock); for (i = 0; i < dev->num_tx_queues; i++) { ret = bcm_sysport_init_tx_ring(priv, i); if (ret) { --- a/drivers/net/ethernet/broadcom/bcmsysport.h +++ b/drivers/net/ethernet/broadcom/bcmsysport.h @@ -660,6 +660,7 @@ struct bcm_sysport_priv { int wol_irq; /* Transmit rings */ + spinlock_t desc_lock; struct bcm_sysport_tx_ring tx_rings[TDMA_NUM_RINGS]; /* Receive queue */