From patchwork Thu Mar 21 23:05:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeremy Linton X-Patchwork-Id: 10864507 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 2A1F86C2 for ; Thu, 21 Mar 2019 23:07:08 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 03F432A53B for ; Thu, 21 Mar 2019 23:07:08 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EC28C2A53D; Thu, 21 Mar 2019 23:07:07 +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 954962A53B for ; Thu, 21 Mar 2019 23:07:07 +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=fMk9yhbEw7c2BjycFKYa1pEa0FeGVj2NRPrY3O+WlUU=; b=bjvVNDNGfVMGX0 19xG2KhZsF6amgy2IdRltHOZQqGv/ok45NNdPUqUj+7g3KHAVjhIQMN7dUYvDhQKPVU6wDYtpXJ/U eh2EHWdTJyQ5aBx2gIzw07beTA8tbNiX6arPtFZU6A8kks22fYEbq8s/rzvtPAm4QNpn4VZR+qrUY 8KNYNbMBJj9mEJPzQ15SSvN48bhsoCXeuTgQQJdbyrd0jqEYbn+EMt/ijR2nD76yigf+aNIEIhayz ZWvT+XMhcKvAFu91fxEChdZmPJ6k+DM7UV4qkKo9W69G1DcrkoXoISwk4KTPE9WakXlG1t2t6xNZb GN0ZhxzMxr1rkAes+hnQ==; 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 1h76m6-0007Dp-AH; Thu, 21 Mar 2019 23:07:02 +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 1h76lK-0006DB-O1 for linux-arm-kernel@lists.infradead.org; Thu, 21 Mar 2019 23:06:17 +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 7367516A3; Thu, 21 Mar 2019 16:06:14 -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 C2F543F614; Thu, 21 Mar 2019 16:06:13 -0700 (PDT) From: Jeremy Linton To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 05/10] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2 Date: Thu, 21 Mar 2019 18:05:52 -0500 Message-Id: <20190321230557.45107-6-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_160614_996152_D957E7B5 X-CRM114-Status: GOOD ( 12.70 ) 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 The SMCCC ARCH_WORKAROUND_1 service can indicate that although the firmware knows about the Spectre-v2 mitigation, this particular CPU is not vulnerable, and it is thus not necessary to call the firmware on this CPU. Let's use this information to our benefit. Signed-off-by: Marc Zyngier Signed-off-by: Jeremy Linton Reviewed-by: Andre Przywara Tested-by: Stefan Wahren --- arch/arm64/kernel/cpu_errata.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 2b6e6d8e105b..e5c4c5d84a4e 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -230,22 +230,36 @@ static int detect_harden_bp_fw(void) 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) + switch ((int)res.a0) { + case 1: + /* Firmware says we're just fine */ + return 0; + case 0: + cb = call_hvc_arch_workaround_1; + /* This is a guest, no need to patch KVM vectors */ + smccc_start = NULL; + smccc_end = NULL; + break; + default: return -1; - cb = call_hvc_arch_workaround_1; - /* This is a guest, no need to patch KVM vectors */ - smccc_start = NULL; - smccc_end = NULL; + } break; case PSCI_CONDUIT_SMC: arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID, ARM_SMCCC_ARCH_WORKAROUND_1, &res); - if ((int)res.a0 < 0) + switch ((int)res.a0) { + case 1: + /* Firmware says we're just fine */ + return 0; + case 0: + cb = call_smc_arch_workaround_1; + smccc_start = __smccc_workaround_1_smc_start; + smccc_end = __smccc_workaround_1_smc_end; + break; + default: return -1; - cb = call_smc_arch_workaround_1; - smccc_start = __smccc_workaround_1_smc_start; - smccc_end = __smccc_workaround_1_smc_end; + } break; default: