From patchwork Mon Apr 15 21:21:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 162271 Delivered-To: patch@linaro.org Received: by 2002:a02:c6d8:0:0:0:0:0 with SMTP id r24csp3418117jan; Mon, 15 Apr 2019 14:21:42 -0700 (PDT) X-Google-Smtp-Source: APXvYqxju7vHW43AXLzy62fzdBHs5i8l/jqfEPgYWnQViTPka6RSKnM4u7Zwjn42ZfRdR+pMYmNE X-Received: by 2002:a17:902:4501:: with SMTP id m1mr49958506pld.290.1555363302601; Mon, 15 Apr 2019 14:21:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555363302; cv=none; d=google.com; s=arc-20160816; b=GwmCVRCZEC6aWosqwaeOW5Ojl2Rqi4OO+a28S40rw98Wfz7OXJoSjT7Xj2xpzdwTQv F//QO8//4Nrv2eieya3haPkfdZRbx1zVxo0EdW/Gwkrk3S6fI5DBgcgI4y0d69tdTEgp srkqsvaMb2XgPlqNDZmQSixncVKFHJQn1UDx0f5u0rjVnm02/QfT6AcBPE7w7vCsHfUS JEeJE5etebLcJSDy9D+k8j9BHhr5ipQ/EwhA9T+zd2Sv3pKTQqNl2rwt6p8YN4Y1e7pm qLHWznPlFNXjpAaiWyWXI75Oklr9wNDyQ1J2f5tvMzInZ23G24WbfV4rYGABJlpC912k gUaw== 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=SIpbx5lUeUs8KXn4HO2JQDcOS8W/jmLVsApGoKkONhfCLaI1rL4m+1602kWGfNNQVR uPg+lGDeTh+OU9vMkPvLWN/bEQhscRmPpIiirpgFx7qc6Ly/+xbHcrZQWWkgcor5LsMV cgRG97nrui1Qwlkq0GNRD+eT0Ol/aEFnEIBpz8VoDvcut4k2w6LQGJ4FHf1nNJOkf/0g T/4EvK2kry/1eBs1r9RN9zHAX53tjIBezVlVg+QKn/x+nih4WPWbHDmfFM1UOa4BJ5Of I/d7DZgxu5v3lD78WXWLhJ9YuiWjpQqQeNz6ddx/NurEZVS3vX1bK4udzX8uiFF03Xir dqoA== 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 k193si45383232pga.319.2019.04.15.14.21.42; Mon, 15 Apr 2019 14:21:42 -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 S1728024AbfDOVVl (ORCPT + 30 others); Mon, 15 Apr 2019 17:21:41 -0400 Received: from foss.arm.com ([217.140.101.70]:42876 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726041AbfDOVVi (ORCPT ); Mon, 15 Apr 2019 17:21:38 -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 35D2FA78; Mon, 15 Apr 2019 14:21:38 -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 7C0653F68F; Mon, 15 Apr 2019 14:21:37 -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: [v8 01/10] arm64: Provide a command line to disable spectre_v2 mitigation Date: Mon, 15 Apr 2019 16:21:20 -0500 Message-Id: <20190415212129.1112-2-jeremy.linton@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190415212129.1112-1-jeremy.linton@arm.com> References: <20190415212129.1112-1-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;