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, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 60D93C43381 for ; Fri, 12 Mar 2021 15:30:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2743965005 for ; Fri, 12 Mar 2021 15:30:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232071AbhCLPaH (ORCPT ); Fri, 12 Mar 2021 10:30:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:52980 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231883AbhCLP3d (ORCPT ); Fri, 12 Mar 2021 10:29:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id B769664FEE; Fri, 12 Mar 2021 15:29:30 +0000 (UTC) Date: Fri, 12 Mar 2021 15:29:28 +0000 From: Catalin Marinas To: Vincenzo Frascino Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Andrew Morton , Will Deacon , Dmitry Vyukov , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Evgenii Stepanov , Branislav Rankov , Andrey Konovalov , Lorenzo Pieralisi Subject: Re: [PATCH v15 5/8] arm64: mte: Enable TCO in functions that can read beyond buffer limits Message-ID: <20210312152927.GD24210@arm.com> References: <20210312142210.21326-1-vincenzo.frascino@arm.com> <20210312142210.21326-6-vincenzo.frascino@arm.com> <20210312151259.GB24210@arm.com> <31b7a388-4c57-cb25-2d30-da7c37e2b4d6@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <31b7a388-4c57-cb25-2d30-da7c37e2b4d6@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 12, 2021 at 03:23:44PM +0000, Vincenzo Frascino wrote: > On 3/12/21 3:13 PM, Catalin Marinas wrote: > > On Fri, Mar 12, 2021 at 02:22:07PM +0000, Vincenzo Frascino wrote: > >> diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h > >> index 9b557a457f24..8603c6636a7d 100644 > >> --- a/arch/arm64/include/asm/mte.h > >> +++ b/arch/arm64/include/asm/mte.h > >> @@ -90,5 +90,20 @@ static inline void mte_assign_mem_tag_range(void *addr, size_t size) > >> > >> #endif /* CONFIG_ARM64_MTE */ > >> > >> +#ifdef CONFIG_KASAN_HW_TAGS > >> +/* Whether the MTE asynchronous mode is enabled. */ > >> +DECLARE_STATIC_KEY_FALSE(mte_async_mode); > >> + > >> +static inline bool system_uses_mte_async_mode(void) > >> +{ > >> + return static_branch_unlikely(&mte_async_mode); > >> +} > >> +#else > >> +static inline bool system_uses_mte_async_mode(void) > >> +{ > >> + return false; > >> +} > >> +#endif /* CONFIG_KASAN_HW_TAGS */ > > > > You can write this with fewer lines: > > > > DECLARE_STATIC_KEY_FALSE(mte_async_mode); > > > > static inline bool system_uses_mte_async_mode(void) > > { > > return IS_ENABLED(CONFIG_KASAN_HW_TAGS) && > > static_branch_unlikely(&mte_async_mode); > > } > > > > The compiler will ensure that mte_async_mode is not referred when > > !CONFIG_KASAN_HW_TAGS and therefore doesn't need to be defined. > > Yes, I agree, but I introduce "#ifdef CONFIG_KASAN_HW_TAGS" in the successive > patch anyway, according to me the overall code looks more uniform like this. But > I do not have a strong opinion or preference on this. Ah, yes, I didn't look at patch 6 again as it was already reviewed and I forgot the context. Leave it as it is then, my reviewed-by still stands. -- Catalin