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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham 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 76EB3C433DB for ; Thu, 21 Jan 2021 19:38:00 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E5F7423A40 for ; Thu, 21 Jan 2021 19:37:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5F7423A40 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1F2A36B0006; Thu, 21 Jan 2021 14:37:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A24F6B0007; Thu, 21 Jan 2021 14:37:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0B7736B0008; Thu, 21 Jan 2021 14:37:59 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0202.hostedemail.com [216.40.44.202]) by kanga.kvack.org (Postfix) with ESMTP id E79196B0006 for ; Thu, 21 Jan 2021 14:37:58 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id A7A2C8249980 for ; Thu, 21 Jan 2021 19:37:58 +0000 (UTC) X-FDA: 77730792636.06.bee06_0a0fdd527565 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id 8DCA81009DDF4 for ; Thu, 21 Jan 2021 19:37:31 +0000 (UTC) X-HE-Tag: bee06_0a0fdd527565 X-Filterd-Recvd-Size: 5491 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Thu, 21 Jan 2021 19:37:30 +0000 (UTC) Received: by mail-pj1-f54.google.com with SMTP id p15so2293622pjv.3 for ; Thu, 21 Jan 2021 11:37:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Dnk9Enykj65w83ubv86uEi6KNf5yYzMFREtVI9281dI=; b=JWH4tYHbk26CJuY27Dmp0A+zBeE20cqoYeOXBA+lG9CS33vCchR0H9GY3AJPMiQh6b xcIKigTqdsUpwDtrgRiP7W8ZkrU65NwK+EGX/Ocw7kGBuQQ/D5bN6L7iQWT3vdan7lIM /SbynjcuxJf9KmeIrh5SIfXHk7D6lqzOFzNCa6y/Dco1DIuwY1vNsE06WVaXCJDhcloG LZOc9QIK8Vsy3OFNeR62Fav/CvPwmov2OyL+ia/eJs6SFntOcO+PmbCpvcvpCVq/gGyZ G8I99rZfcmHeU32y/zulLUhxGYAUY3tyOn0k2bVBrIJX7NOmP3xI54CK7dyOEkBaYblD kYVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Dnk9Enykj65w83ubv86uEi6KNf5yYzMFREtVI9281dI=; b=nJo3pjfLAGH1/r3Qw9c0RelvHWLA6OqdzgpnkGNbQnRvZJvkobhDFmW/8NfkCQJP7Q 2HLKd54vMj0DYq6X/V+ZXKpzT8XWQK/jl2SpCMGk1XaEDjPCqwpRDGSL/o3wVtOD6gYU Hk2JNUbBRHCze7JvK89wN++mAiyJWYju7NOlYZSIDdeoK8bu67RUl12vlH/4lSzmFjtn IEoxJvdH/PpzcNytJXrs4WPFR6druDlUFpNBMhhzayMXSay07m1tUUCEobWM5hQv3sja efTrL2WKSpTK1orfMwZLSbycmE/x7vFLSA1YZ5RLOEwLns4F6z0XbBdYv3PT9z44/5y/ 8thA== X-Gm-Message-State: AOAM530QOqrU1e0pVl82nDbbrhZQmcpR9y14cY2/hMgejALl6PG65YBf Ht02HK1sBX9dBN2X6Ca6MKMeTCRMXbNGDD5xP9LX4g== X-Google-Smtp-Source: ABdhPJz7qmwzdWABn6nile0A/tLl94zngWGEj4NQpAKrGDxcZmKeyLD1jLxvmvYbq5hgTI5PecRXT4LKsNlm2LjQLew= X-Received: by 2002:a17:90b:30d4:: with SMTP id hi20mr1019865pjb.41.1611257849733; Thu, 21 Jan 2021 11:37:29 -0800 (PST) MIME-Version: 1.0 References: <20200515171612.1020-1-catalin.marinas@arm.com> <20200515171612.1020-25-catalin.marinas@arm.com> In-Reply-To: <20200515171612.1020-25-catalin.marinas@arm.com> From: Andrey Konovalov Date: Thu, 21 Jan 2021 20:37:18 +0100 Message-ID: Subject: Re: [PATCH v4 24/26] arm64: mte: Introduce early param to disable MTE support To: Catalin Marinas Cc: Linux ARM , Linux Memory Management List , linux-arch , Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Peter Collingbourne Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, May 15, 2020 at 7:17 PM Catalin Marinas wrote: > > For performance analysis it may be desirable to disable MTE altogether > via an early param. Introduce arm64.mte_disable and, if true, filter out > the sanitised ID_AA64PFR1_EL1.MTE field to avoid exposing the HWCAP to > user. > > Signed-off-by: Catalin Marinas > Cc: Will Deacon > --- > > Notes: > New in v4. > > Documentation/admin-guide/kernel-parameters.txt | 4 ++++ > arch/arm64/kernel/cpufeature.c | 11 +++++++++++ > 2 files changed, 15 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index f2a93c8679e8..7436e7462b85 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -373,6 +373,10 @@ > arcrimi= [HW,NET] ARCnet - "RIM I" (entirely mem-mapped) cards > Format: ,, > > + arm64.mte_disable= > + [ARM64] Disable Linux support for the Memory > + Tagging Extension (both user and in-kernel). > + > ataflop= [HW,M68k] > > atarimouse= [HW,MOUSE] Atari Mouse > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index aaadc1cbc006..f7596830694f 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -126,12 +126,23 @@ static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap); > static bool __system_matches_cap(unsigned int n); > > #ifdef CONFIG_ARM64_MTE > +static bool mte_disable; > + > +static int __init arm64_mte_disable(char *buf) > +{ > + return strtobool(buf, &mte_disable); > +} > +early_param("arm64.mte_disable", arm64_mte_disable); > + > s64 mte_ftr_filter(const struct arm64_ftr_bits *ftrp, s64 val) > { > struct device_node *np; > static bool memory_checked = false; > static bool mte_capable = true; > > + if (mte_disable) > + return ID_AA64PFR1_MTE_NI; > + > /* EL0-only MTE is not supported by Linux, don't expose it */ > if (val < ID_AA64PFR1_MTE) > return ID_AA64PFR1_MTE_NI; Hi Calatin, While this patch didn't land upstream, we need an MTE kill-switch for Android GKI. Is this patch OK to take as is? Is it still valid? Thanks!