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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 AAA13C43331 for ; Fri, 27 Mar 2020 18:42:18 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 5775F206F2 for ; Fri, 27 Mar 2020 18:42:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5775F206F2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48prLc3W4QzDr3f for ; Sat, 28 Mar 2020 05:42:16 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 48pqrV3KNBzDrBy for ; Sat, 28 Mar 2020 05:19:38 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 02RIJTBJ023044; Fri, 27 Mar 2020 13:19:29 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 02RIJSEO023043; Fri, 27 Mar 2020 13:19:28 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 27 Mar 2020 13:19:28 -0500 From: Segher Boessenkool To: Christophe Leroy Subject: Re: [PATCH v2] powerpc xmon: use `dcbf` inplace of `dcbi` instruction for 64bit Book3S Message-ID: <20200327181928.GJ22482@gate.crashing.org> References: <20200326061522.33123-1-bala24@linux.ibm.com> <9a3c084a-9e86-ff37-111c-6f1a8f0989fc@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9a3c084a-9e86-ff37-111c-6f1a8f0989fc@c-s.fr> User-Agent: Mutt/1.4.2.3i X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ravi.bangoria@linux.ibm.com, Balamuruhan S , paulus@samba.org, sandipan@linux.ibm.com, jniethe5@gmail.com, naveen.n.rao@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Mar 27, 2020 at 04:12:13PM +0100, Christophe Leroy wrote: > Maybe you could also change invalidate_dcache_range(): > > for (i = 0; i < size >> shift; i++, addr += bytes) { > if (IS_ENABLED(CONFIG_PPC_BOOK3S_64)) > dcbf(addr); > else > dcbi(addr); > } But please note that flushing is pretty much the opposite from invalidating (a flush (dcbf) makes sure that what is in the cache now ends up in memory, while an invalidate (dcbi) makes sure it will *not* end up in memory). (Both will remove the addressed cache line from the data caches). So you cannot blindly replace them; in all cases you need to look and see if it does what you need here. (dcbi is much harder to use correctly -- it can race very easily -- so in practice you will be fine most of the time; but be careful around startup code and the like). Segher