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=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 52531C43461 for ; Thu, 17 Sep 2020 17:09:31 +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 CB1A9206CA for ; Thu, 17 Sep 2020 17:09:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Rs7ocLWT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CB1A9206CA 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=/54JJwQffqsVqPL1w++uIGIJiUMNruQZmw5Y98SB+Wg=; b=Rs7ocLWTPNu8RRWrRszzFzzHD T54lrdTppHNpuuR2xwQE5APmucZ2RzXedX5D1Lh6lIO9hhQeF/hnk+Ab328Oe5e170eyzJfAkYFz4 0iN9l/5fTSZoonD5UO9zRsqX8NK/ntVBi78Ype+MABfCt3D4en61GfWk7/SQwBgR3tWX7Cbksy8ih 7094SaT00WJJN5lEPItD7YSlhza4uzS+YLSv6tziyu5cF7OtMPNAhibd3L6GWoh7n+W6Sj6pQkAcm Z2V34nGwjtAVAumodatqTAUM94TzUjJjPuXEFa8gvYEF3nOzkuJlhROnxw5gucbMIZtWbnAEe5fkE ZTfkYgRSg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kIxO6-0003AU-Nh; Thu, 17 Sep 2020 17:08:02 +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 1kIxO2-00038q-GV for linux-arm-kernel@lists.infradead.org; Thu, 17 Sep 2020 17:07:59 +0000 Received: from gaia (unknown [31.124.44.166]) (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 18D84206CA; Thu, 17 Sep 2020 17:07:54 +0000 (UTC) Date: Thu, 17 Sep 2020 18:07:52 +0100 From: Catalin Marinas To: Vincenzo Frascino Subject: Re: [PATCH v2 22/37] arm64: mte: Add in-kernel MTE helpers Message-ID: <20200917170752.GS10662@gaia> References: <4ac1ed624dd1b0851d8cf2861b4f4aac4d2dbc83.1600204505.git.andreyknvl@google.com> <20200917134653.GB10662@gaia> <9ef0a773-71f0-c1d6-b67e-ccf7d8bcbbe6@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <9ef0a773-71f0-c1d6-b67e-ccf7d8bcbbe6@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200917_130758_630631_05CE2C9E X-CRM114-Status: GOOD ( 18.42 ) 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-arm-kernel@lists.infradead.org, Marco Elver , Elena Petrova , Andrey Konovalov , Kevin Brodsky , Will Deacon , Branislav Rankov , kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alexander Potapenko , Evgenii Stepanov , Andrey Ryabinin , Andrew Morton , Dmitry Vyukov 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 Thu, Sep 17, 2020 at 05:17:00PM +0100, Vincenzo Frascino wrote: > On 9/17/20 2:46 PM, Catalin Marinas wrote: > >> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c > >> index 52a0638ed967..e238ffde2679 100644 > >> --- a/arch/arm64/kernel/mte.c > >> +++ b/arch/arm64/kernel/mte.c > >> @@ -72,6 +74,52 @@ int memcmp_pages(struct page *page1, struct page *page2) > >> return ret; > >> } > >> > >> +u8 mte_get_mem_tag(void *addr) > >> +{ > >> + if (system_supports_mte()) > >> + asm volatile(ALTERNATIVE("ldr %0, [%0]", > >> + __MTE_PREAMBLE "ldg %0, [%0]", > >> + ARM64_MTE) > >> + : "+r" (addr)); > > This doesn't do what you think it does. LDG indeed reads the tag from > > memory but LDR loads the actual data at that address. Instead of the > > first LDR, you may want something like "mov %0, #0xf << 56" (and use > > some macros to avoid the hard-coded 56). > > > > Seems I can't encode a shift of 56 neither in mov nor in orr. I propose to > replace both with an and of the address with itself. > This should not change anything. Then use a NOP. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel