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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 CCCC9C55178 for ; Thu, 5 Nov 2020 17:39:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7D72C2083B for ; Thu, 5 Nov 2020 17:39:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731609AbgKERjK (ORCPT ); Thu, 5 Nov 2020 12:39:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:34576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725862AbgKERjJ (ORCPT ); Thu, 5 Nov 2020 12:39:09 -0500 Received: from gaia (unknown [2.26.170.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7A230206CA; Thu, 5 Nov 2020 17:39:05 +0000 (UTC) Date: Thu, 5 Nov 2020 17:39:02 +0000 From: Catalin Marinas To: Andrey Konovalov Cc: Will Deacon , Vincenzo Frascino , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Kevin Brodsky , Andrew Morton , kasan-dev , Linux ARM , Linux Memory Management List , LKML Subject: Re: [PATCH v8 30/43] arm64: kasan: Allow enabling in-kernel MTE Message-ID: <20201105173901.GH30030@gaia> References: <5e3c76cac4b161fe39e3fc8ace614400bc2fb5b1.1604531793.git.andreyknvl@google.com> <20201105172549.GE30030@gaia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 05, 2020 at 06:29:17PM +0100, Andrey Konovalov wrote: > On Thu, Nov 5, 2020 at 6:26 PM Catalin Marinas wrote: > > > > On Thu, Nov 05, 2020 at 12:18:45AM +0100, Andrey Konovalov wrote: > > > diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c > > > index 06ba6c923ab7..fcfbefcc3174 100644 > > > --- a/arch/arm64/kernel/mte.c > > > +++ b/arch/arm64/kernel/mte.c > > > @@ -121,6 +121,13 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag) > > > return ptr; > > > } > > > > > > +void __init mte_init_tags(u64 max_tag) > > > +{ > > > + /* Enable MTE Sync Mode for EL1. */ > > > + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); > > > + isb(); > > > +} > > > > Is this going to be called on each CPU? I quickly went through the rest > > of the patches and couldn't see how. > > Yes, on each CPU. This is done via kasan_init_hw_tags() that is called > from cpu_enable_mte(). This change is added in the "kasan, arm64: > implement HW_TAGS runtime". Ah, I got there eventually in patch 38. Too many indirections ;) (I'm sure we could have trimmed them down a bit, hw_init_tags == arch_init_tags == mte_init_tags). > Would it make sense to put it into a separate patch? I think that's fine. I had the impression that kasan_init_hw_tags() should only be called once. -- Catalin