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: 162044 Delivered-To: patch@linaro.org Received: by 2002:a02:c6d8:0:0:0:0:0 with SMTP id r24csp6763021jan; Wed, 10 Apr 2019 16:12:58 -0700 (PDT) X-Google-Smtp-Source: APXvYqwkjFve50vM17e+GF2hCIfPKpVFi7BpAjyfHL+jt2L9Oam5Ks86fIUh0Xx7D3le3prRIDbb X-Received: by 2002:a17:902:6b03:: with SMTP id o3mr46816577plk.226.1554937978855; Wed, 10 Apr 2019 16:12:58 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1554937978; cv=none; d=google.com; s=arc-20160816; b=i22qo2XfDDAgPLzoSVIW/73LbYDdY1sM+BuA7OnaMK5Xh19xzfPjbA7ucd4EPR2JH1 yMrRf7SOxU0Za58SvEu5eUCNsAO454GkRfZwsQolof+VPmUAKTID3+8rbuMEKGAxpkX5 1XweZRc5lVe6YcRHUZ38FJ9wjr6slUHDzN5mDvWG+HeaSdbOm60Z8pO4yHHXIk1Mp4kU taokABTUG+uz6TBY2j3uYvCnDdg2r1oC9eJgrhxGHeLhNNNWy4ptXD0sL8x/79peIXzp 3ATS/TDyFHhM1OkkKwPdYm1FLXVV9QFvSuQc0m0FEiYTr1Bzk+DecIJoNxZ5jDKhBPL1 n5PQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=CT3d/nBKRnTrp1q6CX5C4QJaO2VkT4DsSJpOzC4dACI=; b=IR0Ecxg5lRAUffycHXo5Lrm/5K6zYno7P2/qo+QQfJ8GI4n/7fHqeEHsBxLHqOq3/W JsnbgQP15amM4cpbH/N4EJODeuBvgF1cv1TvFVacmh6yCYopPW8BsDnfAO2VS0PqOpPi WaBkNXokWvqDB3oSshrSPOVeQr9MCJ5BKYi+e68tBhNYZRYxrfKTkcjrxn18Qcr6HWmj gA5ll+fWErZdPNyTWak74gJqpCphmXRPWAXQEPdzuYzGvWH5Wn3hnGYuSn9nwwFtKNPE e7uq0ayMvejBDp+vyTF5N2XXaavkcBbg/GfceKwaS4fcs3qmjDjljFpa/yFU7Au6+h7E vucw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id y2si32417243pgl.527.2019.04.10.16.12.58; Wed, 10 Apr 2019 16:12:58 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726818AbfDJXM5 (ORCPT + 31 others); Wed, 10 Apr 2019 19:12:57 -0400 Received: from foss.arm.com ([217.140.101.70]:32978 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726106AbfDJXMz (ORCPT ); Wed, 10 Apr 2019 19:12:55 -0400 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 Cc: catalin.marinas@arm.com, will.deacon@arm.com, marc.zyngier@arm.com, suzuki.poulose@arm.com, Dave.Martin@arm.com, shankerd@codeaurora.org, julien.thierry@arm.com, mlangsdo@redhat.com, stefan.wahren@i2se.com, Andre.Przywara@arm.com, linux-kernel@vger.kernel.org, Jeremy Linton , Andre Przywara , Jonathan Corbet , linux-doc@vger.kernel.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 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(-) -- 2.20.1 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;