From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net v2 0/2] sfc: Restrict PIO for 64bit arch in order to avoid data corruption Date: Fri, 30 May 2014 17:38:20 -0700 (PDT) Message-ID: <20140530.173820.494414338220972060.davem@davemloft.net> References: <5385AAF5.7090001@solarflare.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, linux-net-drivers@solarflare.com To: sshah@solarflare.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:60863 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934624AbaEaAiV (ORCPT ); Fri, 30 May 2014 20:38:21 -0400 In-Reply-To: <5385AAF5.7090001@solarflare.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Shradha Shah Date: Wed, 28 May 2014 10:23:01 +0100 > This patch series > Fixes: ee45fd92c739db5b7950163d91dfe5f016af6d24 > > The linux net driver uses memcpy_toio() in order to copy into > the PIO buffers. > Even on a 64bit machine this causes 32bit accesses to a write- > combined memory region. > There are hardware limitations that mean that only > 64bit naturally aligned accesses are safe in all cases. Due to being > write-combined memory region two 32bit accesses may be coalesced to > form a 64bit non 64bit aligned access. > Solution was to open-code the memory copy routines using pointers > and to only enable PIO for x86_64 machines. > > This bug fix applies to v3.13 and v3.14 stable branches. You submited this twice and I'm still confused which ones I should use. Please resubmit this and address Sergei's feedback, thank you.