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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 7F348CA9EAF for ; Fri, 25 Oct 2019 02:47:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2B5E221D7B for ; Fri, 25 Oct 2019 02:47:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390768AbfJYCrp (ORCPT ); Thu, 24 Oct 2019 22:47:45 -0400 Received: from gate.crashing.org ([63.228.1.57]:53148 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728416AbfJYCro (ORCPT ); Thu, 24 Oct 2019 22:47:44 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x9P2lPkV002163; Thu, 24 Oct 2019 21:47:26 -0500 Message-ID: <572a7d510ace5e5a5ba41c4774d330133291c82a.camel@kernel.crashing.org> Subject: [PATCH] net: ethernet: ftgmac100: Fix DMA coherency issue with SW checksum From: Benjamin Herrenschmidt To: "David S. Miller" Cc: netdev@vger.kernel.org, "linux-kernel@vger.kernel.org" , Vijay Khemka , openbmc@lists.ozlabs.org, Joel Stanley , linux-aspeed@lists.ozlabs.org Date: Fri, 25 Oct 2019 13:47:24 +1100 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We are calling the checksum helper after the dma_map_single() call to map the packet. This is incorrect as the checksumming code will touch the packet from the CPU. This means the cache won't be properly flushes (or the bounce buffering will leave us with the unmodified packet to DMA). This moves the calculation of the checksum & vlan tags to before the DMA mapping. This also has the side effect of fixing another bug: If the checksum helper fails, we goto "drop" to drop the packet, which will not unmap the DMA mapping. Signed-off-by: Benjamin Herrenschmidt Fixes: 05690d633f30 ftgmac100: Upgrade to NETIF_F_HW_CSUM CC: stable@vger.kernel.org [v4.12+] --- drivers/net/ethernet/faraday/ftgmac100.c | 25 ++++++++++++------------ 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c index 9b7af94a40bb..96e9565f1e08 100644 --- a/drivers/net/ethernet/faraday/ftgmac100.c +++ b/drivers/net/ethernet/faraday/ftgmac100.c @@ -727,6 +727,18 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb, */ nfrags = skb_shinfo(skb)->nr_frags; + /* Setup HW checksumming */ + csum_vlan = 0; + if (skb->ip_summed == CHECKSUM_PARTIAL && + !ftgmac100_prep_tx_csum(skb, &csum_vlan)) + goto drop; + + /* Add VLAN tag */ + if (skb_vlan_tag_present(skb)) { + csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG; + csum_vlan |= skb_vlan_tag_get(skb) & 0xffff; + } + /* Get header len */ len = skb_headlen(skb); @@ -753,19 +765,6 @@ static netdev_tx_t ftgmac100_hard_start_xmit(struct sk_buff *skb, if (nfrags == 0) f_ctl_stat |= FTGMAC100_TXDES0_LTS; txdes->txdes3 = cpu_to_le32(map); - - /* Setup HW checksumming */ - csum_vlan = 0; - if (skb->ip_summed == CHECKSUM_PARTIAL && - !ftgmac100_prep_tx_csum(skb, &csum_vlan)) - goto drop; - - /* Add VLAN tag */ - if (skb_vlan_tag_present(skb)) { - csum_vlan |= FTGMAC100_TXDES1_INS_VLANTAG; - csum_vlan |= skb_vlan_tag_get(skb) & 0xffff; - } - txdes->txdes1 = cpu_to_le32(csum_vlan); /* Next descriptor */