From patchwork Thu Jan 2 12:39:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Murray X-Patchwork-Id: 11315667 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B13AB109A for ; Thu, 2 Jan 2020 12:39:25 +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 7F29F20863 for ; Thu, 2 Jan 2020 12:39:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="VRMXc9XT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F29F20863 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+patchwork-linux-arm=patchwork.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-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=1f69mWOxOGEvYh2zQWzgK+RnaAo1W52fzL7wJ1wNEcA=; b=VRMXc9XTkPIJXm nrt1eb4gkIOfhXPB7rMPITHDKLccDxL5LCdS6F2qxyEbPzx0pM0A8LnrAEzxrfYA11oxRUm2GYfVq u4hqX1Zl0/uAl/DFHqIhFExbZ3vrIFCRJtS68omCZzVY/gaLlJ4IGQDmq9HR1BLVqj4tkaGNXxcNB x0PZVTJArawIJnXnjo7yFk15SyLeltfTO8kLmyxsL/3uKTsnzsaHamrjGBySjAKbkKilM6lNEanV2 ue0AK+oo64rQFcyjgR1oJvz425g2iut4Ren/tvzT1mwYl9VjQcgJxFucvOM4eXDoswxhqRLqF/xFZ ck0uTPxcbfN/py0/yZhg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1imzl5-0005fm-F8; Thu, 02 Jan 2020 12:39:23 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1imzky-0005YD-E3 for linux-arm-kernel@lists.infradead.org; Thu, 02 Jan 2020 12:39:17 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 41BADDA7; Thu, 2 Jan 2020 04:39:14 -0800 (PST) Received: from e119886-lin.cambridge.arm.com (unknown [10.37.6.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B8A323F703; Thu, 2 Jan 2020 04:39:12 -0800 (PST) From: Andrew Murray To: Catalin Marinas , Will Deacon , Marc Zyngier , Mark Rutland Subject: [PATCH v3 1/3] arm64: cpufeature: Extract capped fields Date: Thu, 2 Jan 2020 12:39:03 +0000 Message-Id: <20200102123905.29360-2-andrew.murray@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200102123905.29360-1-andrew.murray@arm.com> References: <20200102123905.29360-1-andrew.murray@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200102_043916_512099_DB421D7F X-CRM114-Status: GOOD ( 10.66 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [217.140.110.172 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record 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: kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Suzuki Kuruppassery Poulose Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org When emulating ID registers there is often a need to cap the version bits of a feature such that the guest will not use features that do not yet exist. Let's add a helper that extracts a field and caps the version to a given value. Signed-off-by: Andrew Murray Reviewed-by: Suzuki K Poulose --- arch/arm64/include/asm/cpufeature.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 4261d55e8506..1462fd1101e3 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -447,6 +447,22 @@ cpuid_feature_extract_unsigned_field(u64 features, int field) return cpuid_feature_extract_unsigned_field_width(features, field, 4); } +static inline u64 __attribute_const__ +cpuid_feature_cap_signed_field_width(u64 features, int field, int width, + s64 cap) +{ + s64 val = cpuid_feature_extract_signed_field_width(features, field, + width); + u64 mask = GENMASK_ULL(field + width - 1, field); + + if (val > cap) { + features &= ~mask; + features |= (cap << field) & mask; + } + + return features; +} + static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp) { return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);