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=-19.7 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=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 14B9AC4320A for ; Fri, 30 Jul 2021 11:26:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2B1060E93 for ; Fri, 30 Jul 2021 11:26:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238858AbhG3L0I (ORCPT ); Fri, 30 Jul 2021 07:26:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:37160 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238772AbhG3LZw (ORCPT ); Fri, 30 Jul 2021 07:25:52 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3C38061052; Fri, 30 Jul 2021 11:25:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627644347; bh=TCVWFCgzUBmJBt37TzROmSpk2UW8evs3tu2IpPF1E/s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pRhw08r1vUHHmuR84BHVI846ZNn3oCtHdEaaEwLKcTognoC+dHe9WgIDmGOs6Gzwo 089IvMeq6Mkl/DO/7ZYR0x8ZsLr0CZkT8ArsGeFRMwWYBW9vUhfr/Mj7yg4wMBXtfL 2kd+8WYGTvybi43xB0rdO2lk7N0AoaHV1PrUNsZsu3NxOhWe3QLm8X0OH93D1vrRHu sfUugggl+7x/i2Qbu/ApCk3n2brOfPTOwsZQUa8ZKtow0mP7pgYXzsWqmmJlfyELBY uWCPmiVO1wvEhxbXUWA6AnnNb/wgAkL9LT4zd9EwU1bukeuptZYuK5B9e2E51Ld4fk 6tOZ6F/luICVg== 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 , Valentin Schneider , Mark Rutland , kernel-team@android.com Subject: [PATCH v11 14/16] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Date: Fri, 30 Jul 2021 12:24:41 +0100 Message-Id: <20210730112443.23245-15-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210730112443.23245-1-will@kernel.org> References: <20210730112443.23245-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 bdb22006f713..6ab625dea8c0 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 7ee1095a4585..a306ed5a6549 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1321,6 +1321,13 @@ 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) { -- 2.32.0.402.g57bb445576-goog