From patchwork Wed Apr 10 23:12:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 10894847 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B18AF13B5 for ; Wed, 10 Apr 2019 23:13:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9635B28BA0 for ; Wed, 10 Apr 2019 23:13:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8A1EE28BB8; Wed, 10 Apr 2019 23:13:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 0A93B28BD4 for ; Wed, 10 Apr 2019 23:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aDneQU/aPiEfwS8V/yUOu0tPaC/BazG0phiea0cScek=; b=PExq4bQL+DYhoG KjEIsxPeBNXMX3G2jD7GyQyoktrncUXbMgnoQkRLhyEurMaJrCODhoRdCPB8afu8h7ZTXDFzZN0Wf u+8X2/8+d0W/1XJxK/5KRsNM9aIyvEXSqWydWRvf2fnKpn3UgSSMrJbibMexXiproSyq/QHC8Vh3n 3ffyNMvYb50OgPLQr8lBeeryvoH7NedlJ5QKKPBafFjqonWwh9Wd9AVgaDFt6zlXIoUVdIdok8LcY 343oOiz/vIvI4CMdzpzjG3/gutV8oY/Iwg2ksBXbqjiqIi7TU/PVjwQoh0IwMducI2GCc7FrcN0uJ WotAuzEDm6X2FGSe7pDQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hEMOr-0003D7-0B; Wed, 10 Apr 2019 23:13:01 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hEMOn-0003AJ-GE for linux-arm-kernel@lists.infradead.org; Wed, 10 Apr 2019 23:12:59 +0000 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 C53FAA78; Wed, 10 Apr 2019 16:12:54 -0700 (PDT) Received: from mammon-tx2.austin.arm.com (mammon-tx2.austin.arm.com [10.118.29.246]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 154623F557; Wed, 10 Apr 2019 16:12:54 -0700 (PDT) From: Jeremy Linton To: linux-arm-kernel@lists.infradead.org Subject: [v7 01/10] arm64: Provide a command line to disable spectre_v2 mitigation Date: Wed, 10 Apr 2019 18:12:28 -0500 Message-Id: <20190410231237.52506-2-jeremy.linton@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190410231237.52506-1-jeremy.linton@arm.com> References: <20190410231237.52506-1-jeremy.linton@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190410_161257_548486_1407D88A X-CRM114-Status: GOOD ( 11.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: stefan.wahren@i2se.com, Jonathan Corbet , mlangsdo@redhat.com, linux-doc@vger.kernel.org, suzuki.poulose@arm.com, marc.zyngier@arm.com, catalin.marinas@arm.com, julien.thierry@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, Jeremy Linton , Andre Przywara , Dave.Martin@arm.com, shankerd@codeaurora.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP There are various reasons, including bencmarking, to disable spectrev2 mitigation on a machine. Provide a command-line to do so. Signed-off-by: Jeremy Linton Reviewed-by: Suzuki K Poulose Reviewed-by: Andre Przywara Reviewed-by: Catalin Marinas Tested-by: Stefan Wahren Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++---- arch/arm64/kernel/cpu_errata.c | 13 +++++++++++++ 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2b8ee90bb644..d153bb15c8c7 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2873,10 +2873,10 @@ check bypass). With this option data leaks are possible in the system. - nospectre_v2 [X86,PPC_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2 - (indirect branch prediction) vulnerability. System may - allow data leaks with this option, which is equivalent - to spectre_v2=off. + nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for + the Spectre variant 2 (indirect branch prediction) + vulnerability. System may allow data leaks with this + option. nospec_store_bypass_disable [HW] Disable all mitigations for the Speculative Store Bypass vulnerability diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 9950bb0cbd52..d2b2c69d31bb 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -220,6 +220,14 @@ static void qcom_link_stack_sanitization(void) : "=&r" (tmp)); } +static bool __nospectre_v2; +static int __init parse_nospectre_v2(char *str) +{ + __nospectre_v2 = true; + return 0; +} +early_param("nospectre_v2", parse_nospectre_v2); + static void enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry) { @@ -231,6 +239,11 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry) if (!entry->matches(entry, SCOPE_LOCAL_CPU)) return; + if (__nospectre_v2) { + pr_info_once("spectrev2 mitigation disabled by command line option\n"); + return; + } + if (psci_ops.smccc_version == SMCCC_VERSION_1_0) return;