From patchwork Wed Apr 10 23:12:34 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 10894891 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 51E7F13B5 for ; Wed, 10 Apr 2019 23:21:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 38A2D28C5A for ; Wed, 10 Apr 2019 23:21:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2C3DD28C63; Wed, 10 Apr 2019 23:21:51 +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 A084D28C64 for ; Wed, 10 Apr 2019 23:21:50 +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=luTEkFSgCUzPqvDB73HCLkBw5PWnyFkIL8klp6UNMWc=; b=EppguGitTFo9kT Ji3wV3tWly3ZnbH0FfkrLmgoZfS1vaKNrNWNw3S1Bcw/Utg0V0VAOMaRRg+rtS7P7D8q63xMPRS6K PRc1uV83Z/DpbM52H6LNfiMGrZ3bbIXEwKO6ZYdcPNJjLtl+y/CXTLRXtkn8HiBAy2UmLFe2G6wEw 8VfSOGizjcJ5EgO5T9BqVVJmPIuoJSyFUnIoad4KWjw6QwS46ssqM8i/O91jDVfzGePB/tvVNpnSE N24xir8pLw1MED3v33iVZWITXzlGjI3FW+Xjnz+nvLkSHxOxwe31/VcM41BMhmSez0m1TON36QEpu yicTLS+lP6/TUCjKoNFg==; 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 1hEMXN-0002dp-Vv; Wed, 10 Apr 2019 23:21:49 +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 1hEMOp-0003C7-Ug for linux-arm-kernel@lists.infradead.org; Wed, 10 Apr 2019 23:13:01 +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 DB8C51713; Wed, 10 Apr 2019 16:12:58 -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 3D4DD3F557; Wed, 10 Apr 2019 16:12:58 -0700 (PDT) From: Jeremy Linton To: linux-arm-kernel@lists.infradead.org Subject: [v7 07/10] arm64: add sysfs vulnerability show for spectre v2 Date: Wed, 10 Apr 2019 18:12:34 -0500 Message-Id: <20190410231237.52506-8-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_161300_030079_9448B684 X-CRM114-Status: GOOD ( 14.42 ) 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, 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 , 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 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 Reviewed-by: Catalin Marinas Tested-by: Stefan Wahren --- 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 74c4a66500c4..fb8eb6c6088f 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -512,6 +512,10 @@ 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. */ @@ -522,6 +526,10 @@ 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) { @@ -543,19 +551,25 @@ 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); } @@ -778,3 +792,15 @@ 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"); +}