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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iIU8t-0005Hm-3e; Thu, 10 Oct 2019 08:49:51 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iIU7f-00040h-S3 for linux-arm-kernel@lists.infradead.org; Thu, 10 Oct 2019 08:48:38 +0000 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0C7EF218AC; Thu, 10 Oct 2019 08:48:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570697315; bh=4+ddVrSlwKEXvHJR9TXUtVJv03PE9mTWulwBohgF+iE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S77g7MFM0uw3xzeRJW4dgLxcF1HRSz6vVUtcMwhSt1GdxOMo7LAflk44Y97sR0Vxg /Sb6cK6NPvEk8z3cMRjNciAH7kmiJPQItwrrTfGQuT6PTWpvFllM9UVZU6h6iMDt55 jcDVRH3Zm06v+J6qLI/ar0fIYXKZBYiO4YQAeBNY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 4.19 098/114] arm64: Advertise mitigation of Spectre-v2, or lack thereof Date: Thu, 10 Oct 2019 10:36:45 +0200 Message-Id: <20191010083613.354710166@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191010083544.711104709@linuxfoundation.org> References: <20191010083544.711104709@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191010_014835_962936_ACBADC67 X-CRM114-Status: GOOD ( 18.09 ) X-Spam-Score: -5.0 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stefan Wahren , Catalin Marinas , Suzuki K Poulose , Marc Zyngier , Greg Kroah-Hartman , Ard Biesheuvel , Will Deacon , Jeremy Linton , stable@vger.kernel.org, Andre Przywara Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org From: Marc Zyngier [ Upstream commit 73f38166095947f3b86b02fbed6bd592223a7ac8 ] 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 Signed-off-by: Jeremy Linton Reviewed-by: Andre Przywara Reviewed-by: Suzuki K Poulose Reviewed-by: Catalin Marinas Tested-by: Stefan Wahren Signed-off-by: Will Deacon Signed-off-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/cpu_errata.c | 109 +++++++++++++++++++++-------------------- 1 file changed, 56 insertions(+), 53 deletions(-) --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -109,9 +109,9 @@ static void __copy_hyp_vect_bpi(int slot __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_SPINLOCK(bp_lock); int cpu, slot = -1; @@ -138,7 +138,7 @@ static void __install_bp_hardening_cb(bp #define __smccc_workaround_1_smc_start NULL #define __smccc_workaround_1_smc_end NULL -static void __install_bp_hardening_cb(bp_hardening_cb_t fn, +static void install_bp_hardening_cb(bp_hardening_cb_t fn, const char *hyp_vecs_start, const char *hyp_vecs_end) { @@ -146,23 +146,6 @@ static void __install_bp_hardening_cb(bp } #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 @@ -197,31 +180,27 @@ static int __init parse_nospectre_v2(cha } 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; @@ -232,23 +211,23 @@ enable_smccc_arch_workaround_1(const str 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 */ @@ -535,24 +514,48 @@ multi_entry_cap_cpu_enable(const struct } #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 @@ -715,8 +718,8 @@ const struct arm64_cpu_capabilities arm6 #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