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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 084E8C4724C for ; Fri, 1 May 2020 10:55:28 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 CA63C2076D for ; Fri, 1 May 2020 10:55:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LqEwdJla"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="uEKrn4o5" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA63C2076D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xXLPDQigAeg0O+QxfJcprTSTqJKecQFjw/doVVNtvbM=; b=LqEwdJlaT4YBhH aY+TBe355/HxRXXjdWtdbQwWsWdjsOrl8rgqwkZiOOhBOfzbB+EjQ3FBQ/bb3u5JymJUCqQRetr1n EYUE5fQzgYe6cASO4EdFMpACWdVO3615GPLhN7MF/a0L6bHDIidnxwetnMxJe2Z7Qj/B2oZBrXsQR HUGJluIRuPlTMj741M4+ai6JKvVXtRm5dNd4OnJ4MZS2Bi9ikcXymygJysGEd9wKyhYcMXcr7ltuh EjLlYCPWd9N6Npp8fpw41CqkizbM5CO/3xcfIPgmq3E1h2CQNr9KLK/WECmghHxrOgQZo8Fybk2wF 9S5bw9rJtNeaTcOh5UEw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jUTKH-0002ED-3I; Fri, 01 May 2020 10:55:25 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jUTKE-0002Dc-Gr for linux-arm-kernel@lists.infradead.org; Fri, 01 May 2020 10:55:23 +0000 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E06052166E; Fri, 1 May 2020 10:55:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588330522; bh=erC6W5Is3Nh/oL4QwwTvkse8Vyv5xbMSlz9NG80pnSs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uEKrn4o5840WtXxkC9WrJ17O5Jlu2T5837fDfIhIeL2APjwSqIXoIC8mLpye/1y/9 13sLP6s7aik7eVuQOxVCXsjN5lnl3XoM4n3Zye2tx6gXqZmiZX0iAeWLo/MDIQpnJQ aytWAXjD/jPWwGbEdZVKarybkBxRoKVTfPxdNT4E= Date: Fri, 1 May 2020 12:55:20 +0200 From: Greg KH To: Mark Rutland Subject: Re: [PATCH] usb: usbfs: correct kernel->user page attribute mismatch Message-ID: <20200501105520.GA1434711@kroah.com> References: <20200430211922.929165-1-jeremy.linton@arm.com> <20200501070500.GA887524@kroah.com> <20200501103712.GA51954@C02TD0UTHF1T.local> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200501103712.GA51954@C02TD0UTHF1T.local> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200501_035522_584179_AB4CAF1F X-CRM114-Status: GOOD ( 14.40 ) 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: git@thegavinli.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, jarkko.sakkinen@linux.intel.com, stern@rowland.harvard.edu, Jeremy Linton , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, May 01, 2020 at 11:37:12AM +0100, Mark Rutland wrote: > On Fri, May 01, 2020 at 09:05:00AM +0200, Greg KH wrote: > > On Thu, Apr 30, 2020 at 04:19:22PM -0500, Jeremy Linton wrote: > > > On arm64, and possibly other architectures, requesting > > > IO coherent memory may return Normal-NC if the underlying > > > hardware isn't coherent. If these pages are then > > > remapped into userspace as Normal, that defeats the > > > purpose of getting Normal-NC, as well as resulting in > > > mappings with differing cache attributes. > > > > What is "Normal-NC"? > > Arm terminology for "Normal Non-Cacheable"; it might be better to say > something like: > > On some architectures (e.g. arm64) an IO coherent mapping may use > non-cachable attributes if the relevant device is cache coherent. > If userspace mappings are cacheable, these may not be coherent with > non-cacheable mappings. On arm64 this is the case for Normal-NC and > Normal (cacheable) mappings. That's better, but it doesn't answer any of my other questions on this patch :) thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel