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 5779AC4363A for ; Tue, 27 Oct 2020 21:51:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 01E3C2224E for ; Tue, 27 Oct 2020 21:51:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603835500; bh=Ka4lRA9eCqvV0mOQOAKOwdP3JXDO0/rJj+vKpZ1rCUc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=F0Eu2DKYqkyWedmwgsB8ZvtVGiNsMA5VZ8u7W8uOqM0TOWEEsUDrMg/62PNtUAqQ7 G0XbpHvKOWfeDbtCBoNCUOUFonm2sstKYw2zcxiDy2N5xUFAieGa3ruG9wdIldiqSP nDJI/URAaPVgWf64R5V4yt78I5i7l0lKqwxvizSI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S374488AbgJ0Vvj (ORCPT ); Tue, 27 Oct 2020 17:51:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:43236 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730075AbgJ0Vvj (ORCPT ); Tue, 27 Oct 2020 17:51:39 -0400 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 C464E22249; Tue, 27 Oct 2020 21:51:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603835498; bh=Ka4lRA9eCqvV0mOQOAKOwdP3JXDO0/rJj+vKpZ1rCUc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cYFhzVnjg1EqcT7oLaMbsjThTi5jopeWooHM/SUSykJR7E/YAYGHKyk+lfPzBCkxB cCP/K9H5xhPonZa32Z4HOPjfWmCtNOoqaT7tLkkUsUF0WYUWjxPu+8RXw68R4JepEW Jd5kaSBSGx0jz4Sp7CbGuy99h2b4hktL2xGYDmXA= 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 , kernel-team@android.com Subject: [PATCH 6/6] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Date: Tue, 27 Oct 2020 21:51:18 +0000 Message-Id: <20201027215118.27003-7-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201027215118.27003-1-will@kernel.org> References: <20201027215118.27003-1-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..1d9021db4d9f 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 not all 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 9f29d4d1ef7e..ccc08da443ec 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1237,6 +1237,13 @@ bool system_has_mismatched_32bit_el0(void) return fld == ID_AA64PFR0_EL0_64BIT_ONLY; } +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 kobject *kobj, struct kobj_attribute *attr, char *buf) { -- 2.29.0.rc2.309.g374f81d7ae-goog