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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 3DB8FC47084 for ; Tue, 25 May 2021 15:17:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23D006141D for ; Tue, 25 May 2021 15:17:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234289AbhEYPSk (ORCPT ); Tue, 25 May 2021 11:18:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:55456 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232656AbhEYPSB (ORCPT ); Tue, 25 May 2021 11:18:01 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 72E906141D; Tue, 25 May 2021 15:16:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621955790; bh=+/Imnr+Lo2MHpB6ujnUBakmFLkmdTTKNQf8pvMFeGqo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CMsDJnKhwUnXSsyJXLrzpp4HjoVRD3S63OQWe/qSC1xxp0FfgSlshU7VAV4lB9tlt a2vKC55LaHtqUTG6HPX6i/f5m0GoX3SN0/oQLTYycrccS+Fupt6spRFqHE+Pt2EbjX FJq2oAMDuRRmqfNNAVfjZQ3z3HbiBJvKzlYQByFCIufApdE3+dSHaEGEfhZ9Fs4rvL uQCF2tZy0dn4c8gKG04jjh1j0A/J4NEjcGRrqVTBdO8zPVKJY72c55iJLAlH+ItyGp mbJFmQPr363ErKG6rJp88QUrdbCb+P7oZvK5ih329JPQZLYse5jjOQk5mcQyB2Kf1s KpMZm+8xwHQkA== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Will Deacon , Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , Dietmar Eggemann , Daniel Bristot de Oliveira , kernel-team@android.com Subject: [PATCH v7 20/22] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Date: Tue, 25 May 2021 16:14:30 +0100 Message-Id: <20210525151432.16875-21-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210525151432.16875-1-will@kernel.org> References: <20210525151432.16875-1-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. Reviewed-by: Catalin Marinas Signed-off-by: Will Deacon --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ arch/arm64/kernel/cpufeature.c | 7 +++++++ 2 files changed, 15 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index cb89dbdedc46..a2e453919bb6 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -287,6 +287,14 @@ 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 + and hot-unplug operations may be restricted. + 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 72efdc611b14..f2c97baa050f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1298,6 +1298,13 @@ const struct cpumask *system_32bit_el0_cpumask(void) return cpu_possible_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) { -- 2.31.1.818.g46aad6cb9e-goog