From patchwork Mon Apr 15 21:21:26 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 10901561 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 78CAC17EF for ; Mon, 15 Apr 2019 21:22:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5AAD6288D2 for ; Mon, 15 Apr 2019 21:22:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4B5F9288D9; Mon, 15 Apr 2019 21:22:52 +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 CC013288D2 for ; Mon, 15 Apr 2019 21:22:51 +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=M9i5/r8wXMZFfK79T46kIRUf0TQSQhx1icudYUCPruE=; b=LZ6d0ffv6NOuC7 Swq5eiTU/cibzc3cWNuhPza410A082FAwCdetZheHzI/fpCVPB0EVF+Br4HYX85Kmm8TGdJc0m76H 3BfXJGFMREYHYZtv9tzXCFnv54PDs/zQ9Rh8GfBkxkS2Le/wn2gcCCtiYQHvEHvp8J4IjpaimSPb1 EWU4R7eSYqfKIVeU2NKec6obT4UUSmQmA5B7GD1sBk9q1cVHJI1LbYZxfe/y3hOmH20VQn66hTm+5 wTtvE4Sq5eu1tWI2ElpeIW9EwH4/rVKG8C7AneRmVP5qEVK3TNUgcxct+DBYZtjt/o8DzgMtUKUod NKtYA700Lr4/HjkseyWA==; 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 1hG93v-0001kv-GW; Mon, 15 Apr 2019 21:22:47 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hG92u-0000Rl-DC for linux-arm-kernel@lists.infradead.org; Mon, 15 Apr 2019 21:21:49 +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 90DB01688; Mon, 15 Apr 2019 14:21:43 -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 E94713F68F; Mon, 15 Apr 2019 14:21:42 -0700 (PDT) From: Jeremy Linton To: linux-arm-kernel@lists.infradead.org Subject: [v8 07/10] arm64: add sysfs vulnerability show for spectre v2 Date: Mon, 15 Apr 2019 16:21:26 -0500 Message-Id: <20190415212129.1112-8-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190415_142144_769044_F014E222 X-CRM114-Status: GOOD ( 16.16 ) 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 bd2cdd22da99..e51ddcb197c0 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"); +}