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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 E6619C43461 for ; Thu, 17 Sep 2020 18:46:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 611FE221E3 for ; Thu, 17 Sep 2020 18:46:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 611FE221E3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 978386B0003; Thu, 17 Sep 2020 14:46:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 94F266B0037; Thu, 17 Sep 2020 14:46:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 83E776B0055; Thu, 17 Sep 2020 14:46:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0182.hostedemail.com [216.40.44.182]) by kanga.kvack.org (Postfix) with ESMTP id 6C2126B0003 for ; Thu, 17 Sep 2020 14:46:06 -0400 (EDT) Received: from smtpin17.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 27E5E349B for ; Thu, 17 Sep 2020 18:46:06 +0000 (UTC) X-FDA: 77273433132.17.event15_410445727124 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin17.hostedemail.com (Postfix) with ESMTP id C7234180CF5EF for ; Thu, 17 Sep 2020 18:45:41 +0000 (UTC) X-HE-Tag: event15_410445727124 X-Filterd-Recvd-Size: 2316 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Thu, 17 Sep 2020 18:45:40 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D847011D4; Thu, 17 Sep 2020 11:45:35 -0700 (PDT) Received: from [10.37.8.97] (unknown [10.37.8.97]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A75B33F718; Thu, 17 Sep 2020 11:45:32 -0700 (PDT) Subject: Re: [PATCH v2 27/37] arm64: mte: Switch GCR_EL1 in kernel entry and exit To: Catalin Marinas , Andrey Konovalov Cc: Dmitry Vyukov , kasan-dev@googlegroups.com, Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Elena Petrova , Branislav Rankov , Kevin Brodsky , Will Deacon , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20200917165221.GF10662@gaia> From: Vincenzo Frascino Message-ID: Date: Thu, 17 Sep 2020 19:47:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200917165221.GF10662@gaia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit 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 9/17/20 5:52 PM, Catalin Marinas wrote: >> +void mte_init_tags(u64 max_tag) >> +{ >> + u64 incl = GENMASK(max_tag & MTE_TAG_MAX, 0); >> + >> + gcr_kernel_excl = ~incl & SYS_GCR_EL1_EXCL_MASK; >> +} > Do we need to set the actual GCR_EL1 register here? We may not get an > exception by the time KASAN starts using it. It is ok not setting it here because to get exceptions cpuframework mte enable needs to be executed first. In that context we set even the register. -- Regards, Vincenzo