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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3F47C433F5 for ; Thu, 31 Mar 2022 12:33:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236173AbiCaMfS (ORCPT ); Thu, 31 Mar 2022 08:35:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235086AbiCaMfQ (ORCPT ); Thu, 31 Mar 2022 08:35:16 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A2482602 for ; Thu, 31 Mar 2022 05:33:29 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id A77D068AFE; Thu, 31 Mar 2022 14:33:22 +0200 (CEST) Date: Thu, 31 Mar 2022 14:33:22 +0200 From: Christoph Hellwig To: Heiko =?iso-8859-1?Q?St=FCbner?= Cc: Christoph Hellwig , palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, wefu@redhat.com, liush@allwinnertech.com, guoren@kernel.org, atishp@atishpatra.org, anup@brainfault.org, drew@beagleboard.org, arnd@arndb.de, wens@csie.org, maxime@cerno.tech, gfavor@ventanamicro.com, andrea.mondelli@huawei.com, behrensj@mit.edu, xinhaoqu@huawei.com, mick@ics.forth.gr, allen.baum@esperantotech.com, jscheid@ventanamicro.com, rtrauben@gmail.com, samuel@sholland.org, cmuellner@linux.com, philipp.tomsich@vrull.eu, Atish Patra Subject: Re: [PATCH v8 01/14] riscv: prevent null-pointer dereference with sbi_remote_fence_i Message-ID: <20220331123322.GA26378@lst.de> References: <20220324000710.575331-1-heiko@sntech.de> <20220324000710.575331-2-heiko@sntech.de> <20220331095155.GA23422@lst.de> <2260961.n0HT0TaD9V@diego> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2260961.n0HT0TaD9V@diego> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 31, 2022 at 02:28:06PM +0200, Heiko Stübner wrote: > so essentially flushes the _local_ icache first and then tries to flush > caches on other cores, either via an ipi or via sbi. > > The remote-fence callback is set correctly during sbi_init(). > The other cores are only brought up after sbi-init is done. > > So it's not really about error reporting but making sure that flush_icache_all() > does something sane even when still running on the first core. > As I assume the "all" means on all available cores (which would be the > core the system booted on). > > Does this make it clearer what this tries to solve? A little. Whatever code calls this early still seems broken to me and just just do a local flush, though.