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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 56D4CC38A2A for ; Fri, 8 May 2020 16:22:32 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 2818621473 for ; Fri, 8 May 2020 16:22:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Fly4wAD6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2818621473 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+infradead-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=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=31k3DO/X0F7lnFZCpjNmCJyTDWy9HUDIovRvFi3weIQ=; b=Fly4wAD6hqqyoXxfJiLybMlSa ppdLmfdVun5l8vh4zfP4xULs5WRg1dDvyBUVR0GQ+0DjrTl9LZAiZLUNFtmiD/pZrZYhsIQEMRzzl 4FIMY1+xNabs81DsThR6Z53/PmNhZt4Y5+c2SCKfW2b50MCfngKcuGPNv4DLryaTHnmvilm7dzzsR O6SiV1/Jo96Qcg24UNq/MIg+UaSbViGJIFLXbFwgEnv9wJmrgD0HBVsowFIgVCa0PPnjOD5X3C+f3 5Px5hiJmRWL/LbdsOGYR79fJMHo+5NCit6CRqxtOJHlVDTBMQxc8Oxi+Cb5KqivGCJoIAsdqqlww/ Ply7umyoQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jX5lc-0008QR-TZ; Fri, 08 May 2020 16:22:28 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jX5lZ-0008Pt-LH for linux-arm-kernel@lists.infradead.org; Fri, 08 May 2020 16:22:27 +0000 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 F06111FB; Fri, 8 May 2020 09:22:21 -0700 (PDT) Received: from [10.57.27.192] (unknown [10.57.27.192]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 296413F71F; Fri, 8 May 2020 09:22:17 -0700 (PDT) Subject: Re: [PATCH v2 3/4] arm64: cpufeature: Modify address authentication cpufeature to exact To: Catalin Marinas References: <1586842314-19527-1-git-send-email-amit.kachhap@arm.com> <1586842314-19527-4-git-send-email-amit.kachhap@arm.com> <20200506171350.GH2878@gaia> From: Amit Kachhap Message-ID: <426d96ef-6a89-6ee5-c0e0-383b297f7f9f@arm.com> Date: Fri, 8 May 2020 21:51:53 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20200506171350.GH2878@gaia> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200508_092225_738363_FE921D6E X-CRM114-Status: GOOD ( 18.67 ) 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: Mark Rutland , Kees Cook , Suzuki K Poulose , Kristina Martsenko , Mark Brown , James Morse , Vincenzo Frascino , Will Deacon , Dave Martin , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 5/6/20 10:43 PM, Catalin Marinas wrote: > On Tue, Apr 14, 2020 at 11:01:53AM +0530, Amit Daniel Kachhap wrote: >> This patch modifies the address authentication cpufeature type to EXACT >> from earlier LOWER_SAFE as the different configurations added for Armv8.6 >> enhanced PAC have different behaviour and there is no tunable to enable the >> lower safe versions. The safe value is set as 0. >> >> After this change, if there is any variation in configurations in secondary >> cpus from boot cpu then those cpus are marked tainted. The KVM guests may >> completely disable address authentication if there is any such variations >> detected. >> >> Signed-off-by: Amit Daniel Kachhap >> --- >> arch/arm64/kernel/cpufeature.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >> index 08795025409c..599b03df2f93 100644 >> --- a/arch/arm64/kernel/cpufeature.c >> +++ b/arch/arm64/kernel/cpufeature.c >> @@ -154,9 +154,9 @@ static const struct arm64_ftr_bits ftr_id_aa64isar1[] = { >> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0), >> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0), >> ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH), >> - FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_API_SHIFT, 4, 0), >> + FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_API_SHIFT, 4, 0), >> ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_PTR_AUTH), >> - FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_APA_SHIFT, 4, 0), >> + FTR_STRICT, FTR_EXACT, ID_AA64ISAR1_APA_SHIFT, 4, 0), >> ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_DPB_SHIFT, 4, 0), >> ARM64_FTR_END, > > Is this sufficient? If we have the boot CPU already enabling the ptrauth > and we get a secondary CPU with a different ISAR1 field that matches the > address auth in cpufeature.c, we still allow it to boot. We no longer > report the feature to the user system_supports_address_auth() is true > while system_supports_generic_auth() would be false as it checks the > sanitised feature registers. Yes agreed. Generic authentication also needs EXACT cpufeature type. > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel