From patchwork Thu Mar 21 23:05:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 10864505 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 229166C2 for ; Thu, 21 Mar 2019 23:06:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB97C2A53A for ; Thu, 21 Mar 2019 23:06:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DF4992A53D; Thu, 21 Mar 2019 23:06:55 +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 46BF62A53A for ; Thu, 21 Mar 2019 23:06:55 +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=AT8DHRciZ5ifCZ7weOKtU1ypTmo6UBDSxOf8MRMbMvY=; b=XT4kNB/SLouATp hLMFqeYdbaBwtDUyzvcrt2c1MMND7T+CJLslEDjG2uLn3MF2SiWTn9TYBQEBkTHOsdzS9Eo7jyVDP 5+9WhlxUegBm1Reka0KOv5w7eUUTfqRBwH74jIBfuzEXPcvilCOqqW1d13TzpWDQ362Zh5D87+WEI JPRaKRzqYneP/NSrJIuufgHbHJTJuuQd+vYjZ2TUV9jywLtvTeNZEcnEc4R+t2ht0wfO7Alxr9yMK MjxBeITkxI6hdmg/Yjt4sOGGyjOKUs5JeFw1IZGaWmBnbPkt6BYXovBMRxAkz84SM+IS5wAYwAimX T1ftkNG441EoPEH83MYg==; 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 1h76lw-0006wk-3t; Thu, 21 Mar 2019 23:06:52 +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 1h76lJ-0006BM-ER for linux-arm-kernel@lists.infradead.org; Thu, 21 Mar 2019 23:06:15 +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 3DC03168F; Thu, 21 Mar 2019 16:06:13 -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 8D7353F614; Thu, 21 Mar 2019 16:06:12 -0700 (PDT) From: Jeremy Linton To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 04/10] arm64: Advertise mitigation of Spectre-v2, or lack thereof Date: Thu, 21 Mar 2019 18:05:51 -0500 Message-Id: <20190321230557.45107-5-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190321_160613_631549_9E64D59C X-CRM114-Status: GOOD ( 20.32 ) 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 , 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 , 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 From: Marc Zyngier We currently have a list of CPUs affected by Spectre-v2, for which we check that the firmware implements ARCH_WORKAROUND_1. It turns out that not all firmwares do implement the required mitigation, and that we fail to let the user know about it. Instead, let's slightly revamp our checks, and rely on a whitelist of cores that are known to be non-vulnerable, and let the user know the status of the mitigation in the kernel log. Signed-off-by: Marc Zyngier [This makes more sense in front of the sysfs patch] [Pick pieces of that patch into this and move it earlier] Signed-off-by: Jeremy Linton Reviewed-by: Andre Przywara Tested-by: Stefan Wahren Reviewed-by: Suzuki K Poulose --- arch/arm64/kernel/cpu_errata.c | 107 +++++++++++++++++---------------- 1 file changed, 55 insertions(+), 52 deletions(-) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index cf623657cf3c..2b6e6d8e105b 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -131,9 +131,9 @@ static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start, __flush_icache_range((uintptr_t)dst, (uintptr_t)dst + SZ_2K); } -static void __install_bp_hardening_cb(bp_hardening_cb_t fn, - const char *hyp_vecs_start, - const char *hyp_vecs_end) +static void install_bp_hardening_cb(bp_hardening_cb_t fn, + const char *hyp_vecs_start, + const char *hyp_vecs_end) { static DEFINE_RAW_SPINLOCK(bp_lock); int cpu, slot = -1; @@ -177,23 +177,6 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, } #endif /* CONFIG_KVM_INDIRECT_VECTORS */ -static void install_bp_hardening_cb(const struct arm64_cpu_capabilities *entry, - bp_hardening_cb_t fn, - const char *hyp_vecs_start, - const char *hyp_vecs_end) -{ - u64 pfr0; - - if (!entry->matches(entry, SCOPE_LOCAL_CPU)) - return; - - pfr0 = read_cpuid(ID_AA64PFR0_EL1); - if (cpuid_feature_extract_unsigned_field(pfr0, ID_AA64PFR0_CSV2_SHIFT)) - return; - - __install_bp_hardening_cb(fn, hyp_vecs_start, hyp_vecs_end); -} - #include #include #include @@ -228,31 +211,27 @@ static int __init parse_nospectre_v2(char *str) } early_param("nospectre_v2", parse_nospectre_v2); -static void -enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry) +/* + * -1: No workaround + * 0: No workaround required + * 1: Workaround installed + */ +static int detect_harden_bp_fw(void) { bp_hardening_cb_t cb; void *smccc_start, *smccc_end; struct arm_smccc_res res; u32 midr = read_cpuid_id(); - 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; + return -1; switch (psci_ops.conduit) { case PSCI_CONDUIT_HVC: arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_ARCH_WORKAROUND_1, &res); if ((int)res.a0 < 0) - return; + return -1; cb = call_hvc_arch_workaround_1; /* This is a guest, no need to patch KVM vectors */ smccc_start = NULL; @@ -263,23 +242,23 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry) arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_ARCH_WORKAROUND_1, &res); if ((int)res.a0 < 0) - return; + return -1; cb = call_smc_arch_workaround_1; smccc_start = __smccc_workaround_1_smc_start; smccc_end = __smccc_workaround_1_smc_end; break; default: - return; + return -1; } if (((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR) || ((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR_V1)) cb = qcom_link_stack_sanitization; - install_bp_hardening_cb(entry, cb, smccc_start, smccc_end); + install_bp_hardening_cb(cb, smccc_start, smccc_end); - return; + return 1; } #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */ @@ -521,24 +500,48 @@ cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused) CAP_MIDR_RANGE_LIST(midr_list) #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR - /* - * List of CPUs where we need to issue a psci call to - * harden the branch predictor. + * List of CPUs that do not need any Spectre-v2 mitigation at all. */ -static const struct midr_range arm64_bp_harden_smccc_cpus[] = { - MIDR_ALL_VERSIONS(MIDR_CORTEX_A57), - MIDR_ALL_VERSIONS(MIDR_CORTEX_A72), - MIDR_ALL_VERSIONS(MIDR_CORTEX_A73), - MIDR_ALL_VERSIONS(MIDR_CORTEX_A75), - MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), - MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), - MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1), - MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR), - MIDR_ALL_VERSIONS(MIDR_NVIDIA_DENVER), - {}, +static const struct midr_range spectre_v2_safe_list[] = { + MIDR_ALL_VERSIONS(MIDR_CORTEX_A35), + MIDR_ALL_VERSIONS(MIDR_CORTEX_A53), + MIDR_ALL_VERSIONS(MIDR_CORTEX_A55), + { /* sentinel */ } }; +static bool __maybe_unused +check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope) +{ + int need_wa; + + WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible()); + + /* If the CPU has CSV2 set, we're safe */ + if (cpuid_feature_extract_unsigned_field(read_cpuid(ID_AA64PFR0_EL1), + ID_AA64PFR0_CSV2_SHIFT)) + return false; + + /* Alternatively, we have a list of unaffected CPUs */ + if (is_midr_in_range_list(read_cpuid_id(), spectre_v2_safe_list)) + return false; + + /* Fallback to firmware detection */ + need_wa = detect_harden_bp_fw(); + if (!need_wa) + return false; + + /* forced off */ + if (__nospectre_v2) { + pr_info_once("spectrev2 mitigation disabled by command line option\n"); + return false; + } + + if (need_wa < 0) + pr_warn_once("ARM_SMCCC_ARCH_WORKAROUND_1 missing from firmware\n"); + + return (need_wa > 0); +} #endif #ifdef CONFIG_HARDEN_EL2_VECTORS @@ -717,8 +720,8 @@ const struct arm64_cpu_capabilities arm64_errata[] = { #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR { .capability = ARM64_HARDEN_BRANCH_PREDICTOR, - .cpu_enable = enable_smccc_arch_workaround_1, - ERRATA_MIDR_RANGE_LIST(arm64_bp_harden_smccc_cpus), + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, + .matches = check_branch_predictor, }, #endif #ifdef CONFIG_HARDEN_EL2_VECTORS