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=-19.0 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,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 A8B10C6379D for ; Tue, 24 Nov 2020 15:51:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 564352087C for ; Tue, 24 Nov 2020 15:51:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="CHScSSwS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390002AbgKXPvX (ORCPT ); Tue, 24 Nov 2020 10:51:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:50866 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389087AbgKXPvW (ORCPT ); Tue, 24 Nov 2020 10:51:22 -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 6B7DF206F7; Tue, 24 Nov 2020 15:51:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606233081; bh=IhklJrTc98DlHw/NyV/h2FIqQqwEhiczqa0G/8pyr58=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CHScSSwSemAKbOAQx6v20ZhR5errvNkNA+8HyRcRf9iVWL/9OgE46NIL5zwd+7MSg uNrVsM99EO2F2A5lQWBNWnpLX4kggtQCJSJv+kYUYRunhGHkS2AlNnD1upNtoCD/Hm aRN0Fs1QmvsTYGnPiEutGKaY4lwpHMQIVrqPS7rQ= 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 , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , kernel-team@android.com Subject: [PATCH v4 08/14] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Date: Tue, 24 Nov 2020 15:50:33 +0000 Message-Id: <20201124155039.13804-9-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201124155039.13804-1-will@kernel.org> References: <20201124155039.13804-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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. Signed-off-by: Will Deacon --- arch/arm64/kernel/process.c | 42 ++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 1540ab0fbf23..72116b0c7c73 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -625,6 +626,45 @@ unsigned long arch_align_stack(unsigned long sp) return sp & ~0xf; } +static void adjust_compat_task_affinity(struct task_struct *p) +{ + cpumask_var_t cpuset_mask; + const struct cpumask *possible_mask = system_32bit_el0_cpumask(); + const struct cpumask *newmask = possible_mask; + + /* + * Restrict the CPU affinity mask for a 32-bit task so that it contains + * only the 32-bit-capable subset of its original CPU mask. If this is + * empty, then try again with the cpuset allowed mask. If that fails, + * forcefully override it with the set of all 32-bit-capable CPUs that + * we know about. + * + * 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(). + */ + if (!restrict_cpus_allowed_ptr(p, possible_mask)) + goto out; + + if (alloc_cpumask_var(&cpuset_mask, GFP_KERNEL)) { + cpuset_cpus_allowed(p, cpuset_mask); + if (cpumask_and(cpuset_mask, cpuset_mask, possible_mask)) { + newmask = cpuset_mask; + goto out_set_mask; + } + } + + if (printk_ratelimit()) { + printk_deferred("Overriding affinity for 32-bit process %d (%s) to CPUs %*pbl\n", + task_pid_nr(p), p->comm, cpumask_pr_args(newmask)); + } +out_set_mask: + set_cpus_allowed_ptr(p, newmask); + free_cpumask_var(cpuset_mask); +out: + set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); +} + /* * Called from setup_new_exec() after (COMPAT_)SET_PERSONALITY. */ @@ -635,7 +675,7 @@ void arch_setup_new_exec(void) if (is_compat_task()) { mmflags = MMCF_AARCH32; if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) - set_tsk_thread_flag(current, TIF_NOTIFY_RESUME); + adjust_compat_task_affinity(current); } current->mm->context.flags = mmflags; -- 2.29.2.454.gaff20da3a2-goog