From patchwork Thu Mar 21 23:05:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 160834 Delivered-To: patch@linaro.org Received: by 2002:a02:c6d8:0:0:0:0:0 with SMTP id r24csp140463jan; Thu, 21 Mar 2019 16:06:54 -0700 (PDT) X-Google-Smtp-Source: APXvYqxfr4e0brYNt3P6ymjgGdWOaof4uUTgldO8xP/HKlEjy8PJzMRnjpLUyh2GRboPsqDynzbK X-Received: by 2002:a62:1b03:: with SMTP id b3mr2294544pfb.150.1553209614196; Thu, 21 Mar 2019 16:06:54 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553209614; cv=none; d=google.com; s=arc-20160816; b=kuAoyHlEgr8s36sc6n5fh6DcwMOkqCMJZkQVMUXPZZcqDfKPcPq+xCmV8N2NtcEWvp Mi5u7uu2eApC5nuCa2UPkQCApeUo4JmM5qADJz2Y1WKHUWB9rAjAj+1vqqizZ5pLTdiM MBDymidP3KgDMMFanb0DM/Y2G2rs22Xe3vj31Tm03xTienu/y8b2zO4Z3zyeFXAQG9Ww Gn6MZ3OPBzsfWzuE+ZnPervxl/D4a17KM6CGMPNcrHvm6oPF9JbtYbkScm2neGAqIvlx hzHCVKjw7byXaA8UhJcJR5Xy8kT5QjCgUWbN5Is3GJ7WFHZ0LWC6ulYvQHItpdzz0UzD E7tA== 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=bIwZNWC78obdfFbQUneozc2o98IM2AfaqrHK55MfyW8=; b=MXCRq6UZW+o/n2FSDJXI5cZ+qffDcUw49eemhL8QP1NdhPOuJFRt3bfgLzAj4coZWH EcyVUdleWsMsZZsOUs2/8gp6oXePzTsYLtG2IzfYd+uNRsDi9vhi0PFIUr4bqlTnypYb lP+smPkwBicXSEBgfvX5GEhZsHSvvm4uNrJ60lMbnhgtHqlpJnYNBIDy0aHxmyEVe021 ERowJ87W64je9EH8f7PGH5ai1cw23SQiOBG+alQ/heM12KdLXHS72w3H7J4wvV2WFBOh lgj03gsChrpkOaob0+dmTCAzchZEXFkiB6FPug+DpIHl49Jso6UfwX8Z9F++Y8bhiqs3 lKhg== 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 i8si4898013pgs.568.2019.03.21.16.06.53; Thu, 21 Mar 2019 16:06:54 -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 S1727385AbfCUXGK (ORCPT + 31 others); Thu, 21 Mar 2019 19:06:10 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:35702 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726695AbfCUXGI (ORCPT ); Thu, 21 Mar 2019 19:06:08 -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 337F3EBD; Thu, 21 Mar 2019 16:06:08 -0700 (PDT) Received: from beelzebub.austin.arm.com (mammon-tx2.austin.arm.com [10.118.29.246]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 7115E3F614; Thu, 21 Mar 2019 16:06:07 -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@i2e.com, Andre.Przywara@arm.com, linux-kernel@vger.kernel.org, Jeremy Linton , Andre Przywara , Stefan Wahren , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH v6 01/10] arm64: Provide a command line to disable spectre_v2 mitigation Date: Thu, 21 Mar 2019 18:05:48 -0500 Message-Id: <20190321230557.45107-2-jeremy.linton@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190321230557.45107-1-jeremy.linton@arm.com> References: <20190321230557.45107-1-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 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;