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=-5.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 80220C433DB for ; Tue, 23 Feb 2021 12:07:11 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 2343C64E3F for ; Tue, 23 Feb 2021 12:07:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2343C64E3F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.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=cEK3rm7eCWCYU5LY42ZYaMTVlDkjo+V8tgW0ozknLJs=; b=PQwFu8mbltnOZPds/oREXjGS5 4/cJfrrvrp51pQW/iD3loxkjdCHwG/RSMfUO8lqycgrBjqPgUpOIj3FWu8d7p3Xb2pgSfBeJFS3OO 4gb6JK9dt15WdCfO8ugs2a7mXnhblRD5dMBsDpv9GpW++inOLpa+b8uVeiwolAk6CnNaLIDuYa0sD w+faT8AJb+Wn1nXI5xwVJ9HGVhn+8KHcSSQum/m/81mBKs3UsK09ak+jnsSqAWYs9DRBADhcNxaQM RYu1txfsY8yx+DsWrUhhwfhBiSHuoOMys+DNs3x5M8k6NMhU4juilbht5QHIfC/o6FuszGiEiKpMt euY8Tc0vg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lEWRg-0008KW-De; Tue, 23 Feb 2021 12:05:40 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lEWRe-0008K0-0U for linux-arm-kernel@lists.infradead.org; Tue, 23 Feb 2021 12:05:38 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 21EEB601FF; Tue, 23 Feb 2021 12:05:34 +0000 (UTC) Date: Tue, 23 Feb 2021 12:05:32 +0000 From: Catalin Marinas To: Vincenzo Frascino Subject: Re: [PATCH v13 4/7] arm64: mte: Enable TCO in functions that can read beyond buffer limits Message-ID: <20210223120530.GA20769@arm.com> References: <20210211153353.29094-1-vincenzo.frascino@arm.com> <20210211153353.29094-5-vincenzo.frascino@arm.com> <20210212172128.GE7718@arm.com> <20210222175825.GE19604@arm.com> <6111633c-3bbd-edfa-86a0-be580a9ebcc8@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <6111633c-3bbd-edfa-86a0-be580a9ebcc8@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210223_070538_115537_6F303563 X-CRM114-Status: GOOD ( 16.98 ) 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: Branislav Rankov , Marco Elver , Lorenzo Pieralisi , Andrey Konovalov , Evgenii Stepanov , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Andrey Ryabinin , Andrew Morton , Will Deacon , Dmitry Vyukov 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 Tue, Feb 23, 2021 at 10:56:46AM +0000, Vincenzo Frascino wrote: > On 2/22/21 5:58 PM, Catalin Marinas wrote: > > We'll still have an issue with dynamically switching the async/sync mode > > at run-time. Luckily kasan doesn't do this now. The problem is that > > until the last CPU have been switched from async to sync, we can't > > toggle the static label. When switching from sync to async, we need > > to do it on the first CPU being switched. > > I totally agree on this point. In the case of runtime switching we might need > the rethink completely the strategy and depends a lot on what we want to allow > and what not. For the kernel I imagine we will need to expose something in sysfs > that affects all the cores and then maybe stop_machine() to propagate it to all > the cores. Do you think having some of the cores running in sync mode and some > in async is a viable solution? stop_machine() is an option indeed. I think it's still possible to run some cores in async while others in sync but the static key here would only be toggled when no async CPUs are left. > Probably it is worth to discuss it further once we cross that bridge. Yes. For now, a warning should do so that we don't forget. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel