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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C070AC54EE9 for ; Wed, 7 Sep 2022 14:15:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=g2Qksm43nolmD6DoT6STJ6n/Gy/z0IrU5lS9aHh9w88=; b=XaUykGbww6Xngm ruPKiSuYAWwKv/C1VQFdTwWsfBXEmeD31yj9wiJGvS17oOydHzsgzWNdmMAlwmCWbR1qnvlWI4FRz ywMK1GD+O7R0bwe2NXMbzqj67NlNQiR4klzTRucf7OgAMEzwGNkaNVC5myshUlscmQTiCd8RTKgIU gRu9CRE4dffWEZrcoI7al51qX9Aa/CIN/06LCs7cZyA8AnIK4r0iQOExXCXoDvrs88bieWhDsYQ3q +AVXpfWZ+7W5BbFQeBmq6SCX1Hx57F8zbponFfeKBV39upDVy2d+F/PO8Rd+/D08zbuT368G4pWUt mGEJXn4lXq2ysqAYcYDg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oVvpP-006lMg-1g; Wed, 07 Sep 2022 14:14:55 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oVvpJ-006lIl-G0 for linux-arm-kernel@lists.infradead.org; Wed, 07 Sep 2022 14:14:50 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 414C668BEB; Wed, 7 Sep 2022 16:14:41 +0200 (CEST) Date: Wed, 7 Sep 2022 16:14:41 +0200 From: Christoph Hellwig To: "Russell King (Oracle)" Cc: Christoph Hellwig , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Mark Rutland , Robin Murphy , Ard Biesheuvel Subject: Re: [PATCH] arm64: dma: Drop cache invalidation from arch_dma_prep_coherent() Message-ID: <20220907141441.GA21984@lst.de> References: <20220823122111.17439-1-will@kernel.org> <20220907090434.GB30704@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220907_071449_704305_0EE37FE9 X-CRM114-Status: GOOD ( 12.64 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 07, 2022 at 03:10:35PM +0100, Russell King (Oracle) wrote: > If we allocate memory, clean (and maybe invalidate) the cache, and then > zero the memory _after_ the clean, then couldn't we be creating dirty > cache lines. There are caches out there that are write-allocate, which > means that by writing zeros to memory, you drag cache lines back into > the cache. When writting through an uncached mapping? _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel