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=-8.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 6A2BAC61DD8 for ; Thu, 12 Nov 2020 09:42:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2250E221FC for ; Thu, 12 Nov 2020 09:42:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727754AbgKLJmq (ORCPT ); Thu, 12 Nov 2020 04:42:46 -0500 Received: from foss.arm.com ([217.140.110.172]:45416 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725928AbgKLJmp (ORCPT ); Thu, 12 Nov 2020 04:42:45 -0500 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 B1806139F; Thu, 12 Nov 2020 01:42:44 -0800 (PST) Received: from [10.37.12.33] (unknown [10.37.12.33]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6C7CC3F73C; Thu, 12 Nov 2020 01:42:40 -0800 (PST) Subject: Re: [PATCH v9 32/44] arm64: mte: Switch GCR_EL1 in kernel entry and exit To: Catalin Marinas , Andrey Konovalov Cc: Will Deacon , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , Andrew Morton , kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <25401c15dc19c7b672771f5b49a208d6e77bfeb5.1605046192.git.andreyknvl@google.com> <20201112093908.GE29613@gaia> From: Vincenzo Frascino Message-ID: Date: Thu, 12 Nov 2020 09:45:45 +0000 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: <20201112093908.GE29613@gaia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/12/20 9:39 AM, Catalin Marinas wrote: > On Tue, Nov 10, 2020 at 11:10:29PM +0100, Andrey Konovalov wrote: >> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c >> index 664c968dc43c..dbda6598c19d 100644 >> --- a/arch/arm64/kernel/mte.c >> +++ b/arch/arm64/kernel/mte.c >> @@ -129,6 +131,26 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag) >> return ptr; >> } >> >> +void mte_init_tags(u64 max_tag) >> +{ >> + static bool gcr_kernel_excl_initialized = false; >> + >> + if (!gcr_kernel_excl_initialized) { >> + /* >> + * The format of the tags in KASAN is 0xFF and in MTE is 0xF. >> + * This conversion extracts an MTE tag from a KASAN tag. >> + */ >> + u64 incl = GENMASK(FIELD_GET(MTE_TAG_MASK >> MTE_TAG_SHIFT, >> + max_tag), 0); >> + >> + gcr_kernel_excl = ~incl & SYS_GCR_EL1_EXCL_MASK; >> + gcr_kernel_excl_initialized = true; >> + } >> + >> + /* Enable the kernel exclude mask for random tags generation. */ >> + write_sysreg_s(SYS_GCR_EL1_RRND | gcr_kernel_excl, SYS_GCR_EL1); >> +} > > I don't think this function belongs to this patch. There is an earlier > patch that talks about mte_init_tags() but no trace of it until this > patch. > Could you please point out to which patch are you referring to? -- Regards, Vincenzo