From patchwork Wed Feb 27 01:05:41 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 10830971 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 7428B1669 for ; Wed, 27 Feb 2019 01:07:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 591A22C5C3 for ; Wed, 27 Feb 2019 01:07:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4A1AC2C5DD; Wed, 27 Feb 2019 01:07:24 +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 E4F502C5C3 for ; Wed, 27 Feb 2019 01:07:23 +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:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: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=qwCV22xm00UWERP6ix28AMV4XMKrCWfef3Z2y51MRF0=; b=lHg8WGwEfPowfrCDM9P56fr1bq 28p9obg8CECN82+PSN+7hlbzvGrj3GGnH5Hi2YaxrjCMLU3/FlOSF0To0tRgHh9V5FsSUmSKDNFof j326EY7PBs4U7V05N7VUemQ2th9Pk4I60ADZbVEyF73bLgM3KRZkLjCsn/QDHF1vu/+hrhCSUbDyz oPVTbaHDLH/wGuxCry2f7X3rInQCmSzt35aT8I3TgWY6lKZ3j0YQbvjoZKMHm61FRKE4GPvRuh7IH 57lVpboerxF/xvS4I2U2CJFYQ5GFzwJI2hgZ5ZRfNor1s273tsydg06aooMBn4B+s0K73DBhg/GQ1 EiGUZmvA==; 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 1gyngp-0007as-VP; Wed, 27 Feb 2019 01:07:15 +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 1gynfl-0006H8-Qk for linux-arm-kernel@lists.infradead.org; Wed, 27 Feb 2019 01:06:12 +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 18F9280D; Tue, 26 Feb 2019 17:06:09 -0800 (PST) Received: from beelzebub.austin.arm.com (beelzebub.austin.arm.com [10.118.12.119]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 7ABD03F5C1; Tue, 26 Feb 2019 17:06:08 -0800 (PST) From: Jeremy Linton To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v5 07/10] arm64: add sysfs vulnerability show for spectre v2 Date: Tue, 26 Feb 2019 19:05:41 -0600 Message-Id: <20190227010544.597579-8-jeremy.linton@arm.com> X-Mailer: git-send-email 2.17.2 In-Reply-To: <20190227010544.597579-1-jeremy.linton@arm.com> References: <20190227010544.597579-1-jeremy.linton@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190226_170610_137368_2DC0080C X-CRM114-Status: GOOD ( 14.18 ) 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: mlangsdo@redhat.com, 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 , stefan.wahren@i2e.com, Andre.Przywara@arm.com, Dave.Martin@arm.com, shankerd@codeaurora.org MIME-Version: 1.0 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 Add code to track whether all the cores in the machine are vulnerable, and whether all the vulnerable cores have been mitigated. Once we have that information we can add the sysfs stub and provide an accurate view of what is known about the machine. Signed-off-by: Jeremy Linton Reviewed-by: Andre Przywara --- arch/arm64/kernel/cpu_errata.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index a27e1ee750e1..0f6e8f5d67bc 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -513,6 +513,10 @@ cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused) .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \ CAP_MIDR_RANGE_LIST(midr_list) +/* Track overall mitigation state. We are only mitigated if all cores are ok */ +static bool __hardenbp_enab = true; +static bool __spectrev2_safe = true; + /* * List of CPUs that do not need any Spectre-v2 mitigation at all. */ @@ -523,6 +527,10 @@ static const struct midr_range spectre_v2_safe_list[] = { { /* sentinel */ } }; +/* + * Track overall bp hardening for all heterogeneous cores in the machine. + * We are only considered "safe" if all booted cores are known safe. + */ static bool __maybe_unused check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope) { @@ -544,19 +552,25 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope) if (!need_wa) return false; + __spectrev2_safe = false; + if (!IS_ENABLED(CONFIG_HARDEN_BRANCH_PREDICTOR)) { pr_warn_once("spectrev2 mitigation disabled by configuration\n"); + __hardenbp_enab = false; return false; } /* forced off */ if (__nospectre_v2) { pr_info_once("spectrev2 mitigation disabled by command line option\n"); + __hardenbp_enab = false; return false; } - if (need_wa < 0) + if (need_wa < 0) { pr_warn_once("ARM_SMCCC_ARCH_WORKAROUND_1 missing from firmware\n"); + __hardenbp_enab = false; + } return (need_wa > 0); } @@ -779,3 +793,15 @@ ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, { return sprintf(buf, "Mitigation: __user pointer sanitization\n"); } + +ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, + char *buf) +{ + if (__spectrev2_safe) + return sprintf(buf, "Not affected\n"); + + if (__hardenbp_enab) + return sprintf(buf, "Mitigation: Branch predictor hardening\n"); + + return sprintf(buf, "Vulnerable\n"); +}