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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable 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 F1120C10F00 for ; Fri, 5 Apr 2019 14:41:52 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 435B5218AE for ; Fri, 5 Apr 2019 14:41:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 435B5218AE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44bMvy0VvMzDqW0 for ; Sat, 6 Apr 2019 01:41:50 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=arm.com (client-ip=217.140.101.70; helo=foss.arm.com; envelope-from=steven.price@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by lists.ozlabs.org (Postfix) with ESMTP id 44bMsz0BxTzDqD8 for ; Sat, 6 Apr 2019 01:40:05 +1100 (AEDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8218C16A3; Fri, 5 Apr 2019 07:40:04 -0700 (PDT) Received: from [10.1.196.69] (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1593E3F68F; Fri, 5 Apr 2019 07:39:59 -0700 (PDT) Subject: Re: [PATCH RFC 5/5] arm64/speculation: Add support for 'cpu_spec_mitigations=' cmdline options To: Josh Poimboeuf , linux-kernel@vger.kernel.org References: <5f70df57b19bbccc4a0d5d76134b4681c9a50b0b.1554396090.git.jpoimboe@redhat.com> From: Steven Price Message-ID: Date: Fri, 5 Apr 2019 15:39:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <5f70df57b19bbccc4a0d5d76134b4681c9a50b0b.1554396090.git.jpoimboe@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Catalin Marinas , Heiko Carstens , Paul Mackerras , "H . Peter Anvin" , Ingo Molnar , Andrea Arcangeli , linux-s390@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, Waiman Long , linux-arch@vger.kernel.org, Will Deacon , Jiri Kosina , linuxppc-dev@lists.ozlabs.org, Borislav Petkov , Andy Lutomirski , Thomas Gleixner , Jon Masters , Greg Kroah-Hartman , Tyler Hicks , Martin Schwidefsky , Linus Torvalds Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 04/04/2019 17:44, Josh Poimboeuf wrote: > Configure arm64 runtime CPU speculation bug mitigations in accordance > with the 'cpu_spec_mitigations=' cmdline options. This affects > Meltdown and Speculative Store Bypass. > > The default behavior is unchanged. > > Signed-off-by: Josh Poimboeuf > --- > Documentation/admin-guide/kernel-parameters.txt | 2 ++ > arch/arm64/kernel/cpu_errata.c | 4 ++++ > arch/arm64/kernel/cpufeature.c | 6 ++++++ > 3 files changed, 12 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index e838af96daa4..0b54385ee7a8 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2553,11 +2553,13 @@ > off > Disable all speculative CPU mitigations. > Equivalent to: nopti [x86, powerpc] > + kpti=0 [arm64] > nospectre_v1 [powerpc] > nospectre_v2 [x86, powerpc, s390] > spectre_v2_user=off [x86] > nobp=0 [s390] > spec_store_bypass_disable=off [x86, powerpc] > + ssbd=force-off [arm64] > l1tf=off [x86] > > auto (default) > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > index 9950bb0cbd52..db8d27e3fb1c 100644 > --- a/arch/arm64/kernel/cpu_errata.c > +++ b/arch/arm64/kernel/cpu_errata.c > @@ -19,6 +19,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -385,6 +386,9 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry, > return false; > } > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) > + ssbd_state = ARM64_SSBD_FORCE_DISABLE; > + > switch (psci_ops.conduit) { > case PSCI_CONDUIT_HVC: > arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 4061de10cea6..4512b582d50f 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -25,6 +25,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -978,6 +979,11 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, > __kpti_forced = -1; > } > > + if (cpu_spec_mitigations == CPU_SPEC_MITIGATIONS_OFF) { > + str = "cpu_spec_mitigations=off"; Might also be worth changing the initialisation of str, currently it is: > char const *str = "command line option"; But now we have two command line options, perhaps "kpti command line option". Steve > + __kpti_forced = -1; > + } > + > /* Forced? */ > if (__kpti_forced) { > pr_info_once("kernel page table isolation forced %s by %s\n", >