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=-4.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 38F2AC433DF for ; Tue, 25 Aug 2020 11:12:28 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EDB632071E for ; Tue, 25 Aug 2020 11:12:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Ssjv3Drq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EDB632071E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=7NQfmHhdGSMx+qP3U8JFQu87qn+OE01qwFxjPvrwlnU=; b=Ssjv3DrqEYGQKL1DvNaDiIVP+ aH3iomy2oLFmtckvRbmR9PiLTwKf0mJnQuXCtQTuKAAbwIcmdaBLgOr9N2qWUCISFClufc+qQH+qv FKn2OhGSufzHRUT2hLvcEeRHLLNrb39C8vYMemZLEYYSmoIqZ0HcUhutZg2p/ae5TCulGTSVYuBFT uUSDaF6oKOzSdNEfAswv1az/LlMsxUMl3ptdyaX3pbmK19YuCNjnbsZh5Xid/mDQR1Y3A8JhtIFb6 98aGF0xayqCU/04pX62bSAG6w/iOq+5ndEXN8ujd2tzf092fSmDVBHPJt+CAh2+dHqzIWr5BJyQcS AnVNIklfw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kAWrA-0001P2-7I; Tue, 25 Aug 2020 11:11:12 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kAWr7-0001Nw-0O for linux-arm-kernel@lists.infradead.org; Tue, 25 Aug 2020 11:11:10 +0000 Received: from C02TF0J2HF1T.local (unknown [213.205.240.110]) (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 61FEE20715; Tue, 25 Aug 2020 11:11:03 +0000 (UTC) Date: Tue, 25 Aug 2020 12:10:59 +0100 From: Catalin Marinas To: Randy Dunlap Subject: Re: [PATCH v8 27/28] arm64: mte: Kconfig entry Message-ID: <20200825111059.GB22233@C02TF0J2HF1T.local> References: <20200824182758.27267-1-catalin.marinas@arm.com> <20200824182758.27267-28-catalin.marinas@arm.com> <2e73f87b-f5fe-5ccf-1b5f-c916703356e0@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <2e73f87b-f5fe-5ccf-1b5f-c916703356e0@infradead.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200825_071109_178000_3092F67F X-CRM114-Status: GOOD ( 21.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arch@vger.kernel.org, Szabolcs Nagy , Andrey Konovalov , Kevin Brodsky , Peter Collingbourne , linux-mm@kvack.org, Andrew Morton , Vincenzo Frascino , Will Deacon , Dave P Martin , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Aug 24, 2020 at 11:44:50AM -0700, Randy Dunlap wrote: > On 8/24/20 11:27 AM, Catalin Marinas wrote: > > index 6d232837cbee..10cf81d70657 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -1664,6 +1664,37 @@ config ARCH_RANDOM > > provides a high bandwidth, cryptographically secure > > hardware random number generator. > > > > +config ARM64_AS_HAS_MTE > > + # Binutils gained initial support for MTE in 2.32.0. However, a > > + # late architecture addition (LDGM/STGM) is only supported in > > + # the newer 2.32.x and 2.33 versions. > > + def_bool $(as-instr,.arch armv8.5-a+memtag\nstgm xzr$(comma)[x0]) > > Would you mind translating that for me? > Yes, I read the v7 Notes, but that only helped a little bit. The initial MTE support in binutils 2.32.0, testable above with ".arch armv8.5-a+memtag", was incomplete. Historically, I think it was based on a beta version of the architecture but before the final architecture release (ARMv8.5), MTE gained a couple of new instructions: STGM/LDGM. Since there are binutils versions out there which don't understand STGM even though they claim to support .arch armv8.5-a+memtag, it's better for the above check to include the STGM instruction. I'll see if I can make the comment above clearer. > > + bool "Memory Tagging Extension support" > > + default y > > + depends on ARM64_AS_HAS_MTE && ARM64_TAGGED_ADDR_ABI > > + select ARCH_USES_HIGH_VMA_FLAGS > > + help > > + Memory Tagging (part of the ARMv8.5 Extensions) provides > > + architectural support for run-time, always-on detection of > > runtime, > as is used below. Thanks. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel