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=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 5C623C1B0D9 for ; Tue, 8 Dec 2020 13:30:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E7B223A79 for ; Tue, 8 Dec 2020 13:30:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729463AbgLHNaU (ORCPT ); Tue, 8 Dec 2020 08:30:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:49582 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729461AbgLHNaT (ORCPT ); Tue, 8 Dec 2020 08:30:19 -0500 From: Will Deacon Authentication-Results: mail.kernel.org; dkim=permerror (bad message/signature format) 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 , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , kernel-team@android.com Subject: [PATCH v5 12/15] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Date: Tue, 8 Dec 2020 13:28:32 +0000 Message-Id: <20201208132835.6151-13-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201208132835.6151-1-will@kernel.org> References: <20201208132835.6151-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org When exec'ing a 32-bit task on a system with mismatched support for 32-bit EL0, try to ensure that it starts life on a CPU that can actually run it. Reviewed-by: Quentin Perret Signed-off-by: Will Deacon --- arch/arm64/kernel/process.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 9a2532d848f0..da313b738c7c 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -633,8 +633,20 @@ void arch_setup_new_exec(void) if (is_compat_task()) { mmflags = MMCF_AARCH32; - if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + + /* + * Restrict the CPU affinity mask for a 32-bit task so that + * it contains only 32-bit-capable CPUs. + * + * From the perspective of the task, this looks similar to + * what would happen if the 64-bit-only CPUs were hot-unplugged + * at the point of execve(), although we try a bit harder to + * honour the cpuset hierarchy. + */ + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) { + force_compatible_cpus_allowed_ptr(current); set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + } } current->mm->context.flags = mmflags; -- 2.29.2.576.ga3fc446d84-goog