From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41B3EC43381 for ; Fri, 1 Mar 2019 06:58:31 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0F9242084F for ; Fri, 1 Mar 2019 06:58:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LHpGIKBG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F9242084F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=s0Ck5eWHSnM6VGtCS8PhscieCQgp8X25xlIjVCjBafk=; b=LHpGIKBGaZg2ynF9Nke+UspRt zE3Z5xYKducYybqBOrDsa+K9QKsq3lZNeX3uQvwc55/CAGH7fVej6XINiuJpm+6zDHBPM3Lv/Dut/ MtAgX6ff0Xe0UHXJpNLATRPHbURW1dqE7UF1oec9Ob4aJ3ZKbtC+BYEC8GCBOVnebthJXnH4xZMGq cMOnGJbwQn+mGQUkZ2LN685UX9dWPR4l1N0uMIjRQEuqRtc/mNHXx1ntqedHUMFdfrO2qFYo2uiph +hVwz2X1HJ15ISygL8yPJd8eWPMZ3TCai4XwUy15FTGR58JBpJtc3LrfLcCQCZeWwhi277201VCTL bFX55CDhw==; 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 1gzc7m-00017J-8I; Fri, 01 Mar 2019 06:58:26 +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 1gzc7j-00016y-EF for linux-arm-kernel@lists.infradead.org; Fri, 01 Mar 2019 06:58:24 +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 DEF36EBD; Thu, 28 Feb 2019 22:58:22 -0800 (PST) Received: from [172.20.0.134] (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0D7653F5C1; Thu, 28 Feb 2019 22:58:21 -0800 (PST) Subject: Re: [PATCH v5 05/10] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2 To: Jeremy Linton , linux-arm-kernel@lists.infradead.org References: <20190227010544.597579-1-jeremy.linton@arm.com> <20190227010544.597579-6-jeremy.linton@arm.com> From: Andre Przywara Message-ID: Date: Fri, 1 Mar 2019 00:58:19 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190227010544.597579-6-jeremy.linton@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190228_225823_491427_FF4C0FFE X-CRM114-Status: GOOD ( 20.80 ) 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: 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, stefan.wahren@i2e.com, Dave.Martin@arm.com, shankerd@codeaurora.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 2/26/19 7:05 PM, Jeremy Linton wrote: > 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. Yes, that matches the firmware interface description. > Signed-off-by: Marc Zyngier > Signed-off-by: Jeremy Linton Reviewed-by: Andre Przywara Cheers, Andre. > --- > 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 c8972255b365..77f021e78a28 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: > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel