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=-10.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 F15BFC433E0 for ; Wed, 27 Jan 2021 03:18:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7973206D6 for ; Wed, 27 Jan 2021 03:18:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231913AbhA0DRP (ORCPT ); Tue, 26 Jan 2021 22:17:15 -0500 Received: from a1.mail.mailgun.net ([198.61.254.60]:23141 "EHLO a1.mail.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388214AbhAZUf7 (ORCPT ); Tue, 26 Jan 2021 15:35:59 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1611693340; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=PksgwQjYAE5mCkWpEhf8FuD4MEP1lZzvNn1nk/aOcJ4=; b=FFlpRz8uAtsaubLt0sgYJ2RAkdiHeZJg0FSo1v4IsgzryuikDFi+1bAnu1zFn28zTvaO6Eld ZfNEXx0+jw+Qny8snpSwqPILecS0+drrOp/AC4MPBAl8u18DEx8t18n6oybr25dRlyZtCemf h87PfUecJK8osriVkPds7F4/hTY= X-Mailgun-Sending-Ip: 198.61.254.60 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-west-2.postgun.com with SMTP id 60107cfdad4c9e395b9242fe (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Tue, 26 Jan 2021 20:35:09 GMT Sender: sramana=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 61CDBC433CA; Tue, 26 Jan 2021 20:35:09 +0000 (UTC) Received: from [192.168.1.11] (cpe-70-95-74-122.san.res.rr.com [70.95.74.122]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: sramana) by smtp.codeaurora.org (Postfix) with ESMTPSA id 836DAC433C6; Tue, 26 Jan 2021 20:35:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 836DAC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=sramana@codeaurora.org Subject: Re: [PATCH v4 19/21] arm64: cpufeatures: Allow disabling of BTI from the command-line To: Catalin Marinas , Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, Will Deacon , Mark Rutland , David Brazdil , Alexandru Elisei , Ard Biesheuvel , Jing Zhang , Ajay Patil , Prasad Sodagudi , James Morse , Julien Thierry , Suzuki K Poulose , kernel-team@android.com References: <20210118094533.2874082-1-maz@kernel.org> <20210118094533.2874082-20-maz@kernel.org> From: Srinivas Ramana Message-ID: Date: Tue, 26 Jan 2021 12:35:05 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Marc, On 1/23/2021 6:24 AM, Catalin Marinas wrote: > On Mon, Jan 18, 2021 at 09:45:31AM +0000, Marc Zyngier wrote: >> In order to be able to disable BTI at runtime, whether it is >> for testing purposes, or to work around HW issues, let's add >> support for overriding the ID_AA64PFR1_EL1.BTI field. >> >> This is further mapped on the arm64.nobti command-line alias. >> >> Signed-off-by: Marc Zyngier > Reviewed-by: Catalin Marinas Verified this Series for BTI as well for command line control. With arm64.nobti: BTI is disabled on both primary and secondary cores as expected(verified page table entries). HWCAPs show no BTI support and kernel instructions are being treated as NOPs. We don't have plan to repeat the test on v5 as there are not major changes here. Tested-by: Srinivas Ramana