From patchwork Fri Feb 3 13:50:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 13127566 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBF15C05027 for ; Fri, 3 Feb 2023 13:52:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233145AbjBCNwb (ORCPT ); Fri, 3 Feb 2023 08:52:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233005AbjBCNwT (ORCPT ); Fri, 3 Feb 2023 08:52:19 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 642899B6D7; Fri, 3 Feb 2023 05:52:05 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 575A815A1; Fri, 3 Feb 2023 05:52:47 -0800 (PST) Received: from eglon.cambridge.arm.com (eglon.cambridge.arm.com [10.1.196.177]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 885F23F71E; Fri, 3 Feb 2023 05:52:01 -0800 (PST) From: James Morse To: linux-pm@vger.kernel.org, loongarch@lists.linux.dev, kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org Cc: Marc Zyngier , Thomas Gleixner , Lorenzo Pieralisi , Mark Rutland , Sudeep Holla , Borislav Petkov , H Peter Anvin , Dave Hansen , Ingo Molnar , Will Deacon , Catalin Marinas , Huacai Chen , James Morse , Suzuki K Poulose , Oliver Upton , Len Brown , Rafael Wysocki , WANG Xuerui , Salil Mehta , Russell King , Jean-Philippe Brucker Subject: [RFC PATCH 03/32] drivers: base: Use present CPUs in GENERIC_CPU_DEVICES Date: Fri, 3 Feb 2023 13:50:14 +0000 Message-Id: <20230203135043.409192-4-james.morse@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230203135043.409192-1-james.morse@arm.com> References: <20230203135043.409192-1-james.morse@arm.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org The four ACPI architectures only create sysfs entries using register_cpu() for present CPUs, whereas GENERIC_CPU_DEVICES does this for possible CPUs. Only two of the eight architectures that use GENERIC_CPU_DEVICES have a distinction between present and possible CPUs. To allow all four ACPI architectures to use GENERIC_CPU_DEVICES, change it to use for_each_present_cpu(). The following architectures use GENERIC_CPU_DEVICES but are not SMP, so possible == present: * m68k * microblaze * nios2 The following architectures use GENERIC_CPU_DEVICES and consider possible == present: * csky: setup_smp() * hexagon: compare smp_start_cpus() and smp_prepare_cpus() * parisc: smp_prepare_boot_cpu() marks the boot cpu as present, processor_probe() sets possible for all CPUs and present for all CPUs except the boot cpu. um appears to be a subarchitecture of x86. The remaining architecture using GENERIC_CPU_DEVICES is openrisc, where smp_init_cpus() makes all CPUs < NR_CPUS possible, whereas smp_prepare_cpus() only makes CPUs < setup_max_cpus present. After this change, openrisc systems that boot with max_cpus=1 would not see other CPUs present in sysfs. This should not be a problem as these CPUs can't be brought online as _cpu_up() checks cpu_present(). Signed-off-by: James Morse --- drivers/base/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 4c98849577d4..cf6407c34ede 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -500,7 +500,7 @@ static void __init cpu_dev_register_generic(void) #ifdef CONFIG_GENERIC_CPU_DEVICES int i; - for_each_possible_cpu(i) { + for_each_present_cpu(i) { if (register_cpu(&per_cpu(cpu_devices, i), i)) panic("Failed to register CPU device"); }