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: 160827 Delivered-To: patch@linaro.org Received: by 2002:a02:c6d8:0:0:0:0:0 with SMTP id r24csp139963jan; Thu, 21 Mar 2019 16:06:18 -0700 (PDT) X-Google-Smtp-Source: APXvYqwdOwG8AUcq0HaZAy0nSLd8FayNlHydQd023Y2CHJiqoT8YdoWUO8z1GJHH8TKrmzahHyU5 X-Received: by 2002:a65:6546:: with SMTP id a6mr5806480pgw.296.1553209578589; Thu, 21 Mar 2019 16:06:18 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553209578; cv=none; d=google.com; s=arc-20160816; b=xAXyZSUAJBaVtXs1epVP7+5EV5WB3Cr8PYAsbHXhNScuO3K3xY4YslcqDNQASxQ9xe Gwej6TeXLMVAZ2CXUQDg80hmTJcHpwjtCUclFHXXvxEe78xI5fY3Qt7lXXgHJwOqO6Rj qceP06Gav1Ji6ODZ+fSe3O3KdzHbzxmd5QwPGMsuB/NevCWLhTX8j4P3eNhg7UPalP1D Obp5FtxU0WsAZRuJCGxoCzz/AT9qQjRfcXVlPVTO0d7nPAqoihVPavk58YdjPrmwXPdb wvy0Oy3lXpuOQGc8YcyQvjRKR7yc5Cmo04CYVL276ZJTgaOVreXK9Bl8f26CK+6hrUNL Ag4A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from; bh=Qeygu4zdPzQMjSCgTQtTy21JQpcsIhU2+1YtX+7whHc=; b=PdpAsk/OrdTd3GDdZAQB/rpQvAZkM9Yb1LGVcTg8E6Hbu03MTYz9SM5N5+t2qdjcSE ckaUfifNh2C92TSYgMSMRs1PHJ+S29G3RMxwfKls3Ny9D3/whJxlPmqaNKbdXp+m2OmE 8XntimawjljuND/eMFm/DL6Q49tIq0Vwr5e1sPLxauxMh8vWqjx4QxZ9jzAHY2TT/J+J 03uXV7hc+RAmzJPZJg31Qsian2xuLw7a2IqBqTZ4lCcO3qzZfasXB+qx0RCXnd8UVHEy zFHv1LWnJAAc/1S9zmVDkQSIIq41c80WmwO7J7CtKVIVCIOxvVlfmktTgHWe4zK6R4Yj V0lQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id h35si5833716plb.180.2019.03.21.16.06.18; Thu, 21 Mar 2019 16:06:18 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727453AbfCUXGR (ORCPT + 31 others); Thu, 21 Mar 2019 19:06:17 -0400 Received: from foss.arm.com ([217.140.101.70]:35762 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727430AbfCUXGO (ORCPT ); Thu, 21 Mar 2019 19:06:14 -0400 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 Cc: catalin.marinas@arm.com, will.deacon@arm.com, marc.zyngier@arm.com, suzuki.poulose@arm.com, Dave.Martin@arm.com, shankerd@codeaurora.org, julien.thierry@arm.com, mlangsdo@redhat.com, stefan.wahren@i2e.com, Andre.Przywara@arm.com, linux-kernel@vger.kernel.org, Jeremy Linton , Andre Przywara , Stefan Wahren 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 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(-) -- 2.20.1 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: