From patchwork Mon Jan 8 17:32:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 10150145 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1EF1B601BE for ; Mon, 8 Jan 2018 17:36:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2200628683 for ; Mon, 8 Jan 2018 17:36:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 16E72286FD; Mon, 8 Jan 2018 17:36:44 +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=-4.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 99DB528683 for ; Mon, 8 Jan 2018 17:36:41 +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=RoJoTUopMaS7H6L7loQ2iPd/j9y2zVLgSNSvO7xugnQ=; b=R4WxLj6Op0fWWXgHZZvPkWP08N osCYDKVmhHe6kja5H1fUHELUtEaf9mQu8lhF8WQF6NuETPuxDaBvVMizbtgmFtA5W/vWJfKkKDgZx dwKTGBINfBNQNLCWaOnqx6eD6RN7PD7xAjXcC8SRFQzii7x5FNJvuI35Kr3qQDoeDMEA8ltd9MKhb V//u/YMncZ9dmvOHw6FF2b+lk382AN99S+OxsgBF6khS26wk9ViN61AV0DucG2T3uR3e2BCT2kbFf Tsv6t4+Hk429fABZYJRTDO/SCFGg3g8AZso/jkVO7zlhXAfQIIDJ0NXIKqTFs3Cz9SvEwK/Tl1UUn +zXfdntg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.89 #1 (Red Hat Linux)) id 1eYbLh-00069n-IU; Mon, 08 Jan 2018 17:36:37 +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 4.89 #1 (Red Hat Linux)) id 1eYbID-0002hB-Nw for linux-arm-kernel@lists.infradead.org; Mon, 08 Jan 2018 17:33:37 +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 57F4319E8; Mon, 8 Jan 2018 09:32:40 -0800 (PST) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2A2343F5AF; Mon, 8 Jan 2018 09:32:40 -0800 (PST) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id A924F1AE30A2; Mon, 8 Jan 2018 17:32:41 +0000 (GMT) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 12/13] arm64: Implement branch predictor hardening for Falkor Date: Mon, 8 Jan 2018 17:32:37 +0000 Message-Id: <1515432758-26440-13-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1515432758-26440-1-git-send-email-will.deacon@arm.com> References: <1515432758-26440-1-git-send-email-will.deacon@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180108_093302_514098_6A5D7722 X-CRM114-Status: GOOD ( 13.09 ) 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: lorenzo.pieralisi@arm.com, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, catalin.marinas@arm.com, Will Deacon , linux-kernel@vger.kernel.org, shankerd@codeaurora.org, christoffer.dall@linaro.org, jnair@caviumnetworks.com 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 From: Shanker Donthineni Falkor is susceptible to branch predictor aliasing and can theoretically be attacked by malicious code. This patch implements a mitigation for these attacks, preventing any malicious entries from affecting other victim contexts. Signed-off-by: Shanker Donthineni [will: fix label name when !CONFIG_KVM] Signed-off-by: Will Deacon --- arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/include/asm/kvm_asm.h | 2 ++ arch/arm64/kernel/bpi.S | 8 +++++++ arch/arm64/kernel/cpu_errata.c | 49 ++++++++++++++++++++++++++++++++++++++-- arch/arm64/kvm/hyp/entry.S | 12 ++++++++++ arch/arm64/kvm/hyp/switch.c | 10 ++++++++ 6 files changed, 81 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 51616e77fe6b..7049b4802587 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -43,7 +43,8 @@ #define ARM64_SVE 22 #define ARM64_UNMAP_KERNEL_AT_EL0 23 #define ARM64_HARDEN_BRANCH_PREDICTOR 24 +#define ARM64_HARDEN_BP_POST_GUEST_EXIT 25 -#define ARM64_NCAPS 25 +#define ARM64_NCAPS 26 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index ab4d0a926043..24961b732e65 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -68,6 +68,8 @@ extern u32 __kvm_get_mdcr_el2(void); extern u32 __init_stage2_translation(void); +extern void __qcom_hyp_sanitize_btac_predictors(void); + #endif #endif /* __ARM_KVM_ASM_H__ */ diff --git a/arch/arm64/kernel/bpi.S b/arch/arm64/kernel/bpi.S index dec95bd82e31..76225c2611ea 100644 --- a/arch/arm64/kernel/bpi.S +++ b/arch/arm64/kernel/bpi.S @@ -77,3 +77,11 @@ ENTRY(__psci_hyp_bp_inval_start) ldp x0, x1, [sp, #(16 * 8)] add sp, sp, #(8 * 18) ENTRY(__psci_hyp_bp_inval_end) + +ENTRY(__qcom_hyp_sanitize_link_stack_start) + stp x29, x30, [sp, #-16]! + .rept 16 + bl . + 4 + .endr + ldp x29, x30, [sp], #16 +ENTRY(__qcom_hyp_sanitize_link_stack_end) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index cb0fb3796bb8..7b4efde087fc 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -54,6 +54,8 @@ DEFINE_PER_CPU_READ_MOSTLY(struct bp_hardening_data, bp_hardening_data); #ifdef CONFIG_KVM extern char __psci_hyp_bp_inval_start[], __psci_hyp_bp_inval_end[]; +extern char __qcom_hyp_sanitize_link_stack_start[]; +extern char __qcom_hyp_sanitize_link_stack_end[]; static void __copy_hyp_vect_bpi(int slot, const char *hyp_vecs_start, const char *hyp_vecs_end) @@ -96,8 +98,10 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn, spin_unlock(&bp_lock); } #else -#define __psci_hyp_bp_inval_start NULL -#define __psci_hyp_bp_inval_end NULL +#define __psci_hyp_bp_inval_start NULL +#define __psci_hyp_bp_inval_end NULL +#define __qcom_hyp_sanitize_link_stack_start NULL +#define __qcom_hyp_sanitize_link_stack_end NULL static void __install_bp_hardening_cb(bp_hardening_cb_t fn, const char *hyp_vecs_start, @@ -138,6 +142,29 @@ static int enable_psci_bp_hardening(void *data) return 0; } + +static void qcom_link_stack_sanitization(void) +{ + u64 tmp; + + asm volatile("mov %0, x30 \n" + ".rept 16 \n" + "bl . + 4 \n" + ".endr \n" + "mov x30, %0 \n" + : "=&r" (tmp)); +} + +static int qcom_enable_link_stack_sanitization(void *data) +{ + const struct arm64_cpu_capabilities *entry = data; + + install_bp_hardening_cb(entry, qcom_link_stack_sanitization, + __qcom_hyp_sanitize_link_stack_start, + __qcom_hyp_sanitize_link_stack_end); + + return 0; +} #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */ #define MIDR_RANGE(model, min, max) \ @@ -302,6 +329,24 @@ const struct arm64_cpu_capabilities arm64_errata[] = { MIDR_ALL_VERSIONS(MIDR_CORTEX_A75), .enable = enable_psci_bp_hardening, }, + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1), + .enable = qcom_enable_link_stack_sanitization, + }, + { + .capability = ARM64_HARDEN_BRANCH_PREDICTOR, + MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR), + .enable = qcom_enable_link_stack_sanitization, + }, + { + .capability = ARM64_HARDEN_BP_POST_GUEST_EXIT, + MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR_V1), + }, + { + .capability = ARM64_HARDEN_BP_POST_GUEST_EXIT, + MIDR_ALL_VERSIONS(MIDR_QCOM_FALKOR), + }, #endif { } diff --git a/arch/arm64/kvm/hyp/entry.S b/arch/arm64/kvm/hyp/entry.S index 12ee62d6d410..9c45c6af1f58 100644 --- a/arch/arm64/kvm/hyp/entry.S +++ b/arch/arm64/kvm/hyp/entry.S @@ -196,3 +196,15 @@ alternative_endif eret ENDPROC(__fpsimd_guest_restore) + +ENTRY(__qcom_hyp_sanitize_btac_predictors) + /** + * Call SMC64 with Silicon provider serviceID 23<<8 (0xc2001700) + * 0xC2000000-0xC200FFFF: assigned to SiP Service Calls + * b15-b0: contains SiP functionID + */ + movz x0, #0x1700 + movk x0, #0xc200, lsl #16 + smc #0 + ret +ENDPROC(__qcom_hyp_sanitize_btac_predictors) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 4d273f6d0e69..7e373791fad1 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -406,6 +406,16 @@ int __hyp_text __kvm_vcpu_run(struct kvm_vcpu *vcpu) /* 0 falls through to be handled out of EL2 */ } + if (cpus_have_const_cap(ARM64_HARDEN_BP_POST_GUEST_EXIT)) { + u32 midr = read_cpuid_id(); + + /* Apply BTAC predictors mitigation to all Falkor chips */ + if (((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR) || + ((midr & MIDR_CPU_MODEL_MASK) == MIDR_QCOM_FALKOR_V1)) { + __qcom_hyp_sanitize_btac_predictors(); + } + } + fp_enabled = __fpsimd_enabled(); __sysreg_save_guest_state(guest_ctxt);