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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 3B375C5517A for ; Mon, 9 Nov 2020 21:30:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D56B920809 for ; Mon, 9 Nov 2020 21:30:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ovDfpcbD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730490AbgKIVav (ORCPT ); Mon, 9 Nov 2020 16:30:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:43156 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725946AbgKIVav (ORCPT ); Mon, 9 Nov 2020 16:30:51 -0500 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4F64A20789; Mon, 9 Nov 2020 21:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604957450; bh=HSjNPPCbNtKAMQvJq+6iKlzbrxmh78a3ebLtKvorRqw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ovDfpcbD4U3KciOkO+oSvqxLFN+b8g53+gTKGYFAJDwIfx3KpSaxmoK1VgWW9gFub WPO7lYPc+W1H8JAHwSqmC1wKHMfZftd6CXPpcW6fWiB0KYhEHllAb4NxujvHmiR2sk 3G1g72b1+Ql7ZgRTr3B3CwMGjjBBYvYE8tMtgNcI= From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , kernel-team@android.com Subject: [PATCH v2 6/6] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Date: Mon, 9 Nov 2020 21:30:22 +0000 Message-Id: <20201109213023.15092-7-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201109213023.15092-1-will@kernel.org> References: <20201109213023.15092-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Allow systems with mismatched 32-bit support at EL0 to run 32-bit applications based on a new kernel parameter. Signed-off-by: Will Deacon --- Documentation/admin-guide/kernel-parameters.txt | 7 +++++++ arch/arm64/kernel/cpufeature.c | 7 +++++++ 2 files changed, 14 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 526d65d8573a..f20188c44d83 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -289,6 +289,13 @@ do not want to use tracing_snapshot_alloc() as it needs to be done where GFP_KERNEL allocations are allowed. + allow_mismatched_32bit_el0 [ARM64] + Allow execve() of 32-bit applications and setting of the + PER_LINUX32 personality on systems where only a strict + subset of the CPUs support 32-bit EL0. When this + parameter is present, the set of CPUs supporting 32-bit + EL0 is indicated by /sys/devices/system/cpu/aarch32_el0. + amd_iommu= [HW,X86-64] Pass parameters to the AMD IOMMU driver in the system. Possible values are: diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index c90f4a18768c..cd106267408a 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1270,6 +1270,13 @@ const struct cpumask *system_32bit_el0_cpumask(void) return cpu_present_mask; } +static int __init parse_32bit_el0_param(char *str) +{ + allow_mismatched_32bit_el0 = true; + return 0; +} +early_param("allow_mismatched_32bit_el0", parse_32bit_el0_param); + static ssize_t aarch32_el0_show(struct device *dev, struct device_attribute *attr, char *buf) { -- 2.29.2.222.g5d2a92d10f8-goog