From nobody Fri Dec 19 07:41:19 2025 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 F34D9C0015E for ; Mon, 24 Jul 2023 13:35:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230352AbjGXNfL (ORCPT ); Mon, 24 Jul 2023 09:35:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36794 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231558AbjGXNeo (ORCPT ); Mon, 24 Jul 2023 09:34:44 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B5821FFE for ; Mon, 24 Jul 2023 06:34:18 -0700 (PDT) Message-ID: <20230724132045.555787669@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1690205652; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=c71eHbYg+VP7OJhjZCVHVzp0AtRxO5V4C+TDLxCJHes=; b=Zdsd/qAkSfkyv7R28hxTmnj8gmeJl+Sk5X2N8xiveIMJFkd8XPmRlQrXnd/6VX5U+F2lIF kNXiNRZdmjiuN3l4BMGRZifB9vSb3+pwS/9cMLK1WALqkQa1l8cTRQQ0FmQQ/XXnhnaeod Y3ImaBtA0xH3dmU7EECqoF+Us6O2qG2htggxB3Y6+CHulp/UcO7ton+jsg09i0B3d2Cuxb XiL49T9wHAWaofWRJs5bEJHbPgev7b90L66QjmYnGAQNmuYIkQz3essgRe6hO9mPOgJan3 KWrDU9HCFkFxZghZOCw4JFX8yNzFja2B7eDgJc4F8mD8LsI17fnZbkWD+4F07w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1690205652; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: references:references; bh=c71eHbYg+VP7OJhjZCVHVzp0AtRxO5V4C+TDLxCJHes=; b=ZeJdIWWQ5lDzV+3Aicl/OcNNEhnGtBOTGMXALhCu54bgHHASFrWxy2Obb3Ogq3bHihKxoB pJbSvCno/WGeh7CA== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Andrew Cooper , Tom Lendacky , Paolo Bonzini , Wei Liu , Arjan van de Ven , Juergen Gross , Michael Kelley , Peter Keresztes Schmidt , "Peter Zijlstra (Intel)" Subject: [patch V2 16/58] x86/apic: Sanitize num_processors handling References: <20230724131206.500814398@linutronix.de> MIME-Version: 1.0 Date: Mon, 24 Jul 2023 15:34:11 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" num_processors is 0 by default and only gets incremented when local APICs are registered. Make init_apic_mappings(), which tries to enable the local APIC in the case that no SMP configuration was found set num_processors to 1. This allows to remove yet another check for the local APIC and yet another place which registers the boot CPUs local APIC ID. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) --- arch/x86/kernel/apic/apic.c | 9 ++++++--- arch/x86/kernel/smpboot.c | 18 ------------------ 2 files changed, 6 insertions(+), 21 deletions(-) --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2130,9 +2130,12 @@ void __init init_apic_mappings(void) if (x2apic_mode) return; =20 - if (!smp_found_config && !detect_init_APIC()) { - pr_info("APIC: disable apic facility\n"); - apic_disable(); + if (!smp_found_config) { + if (!detect_init_APIC()) { + pr_info("APIC: disable apic facility\n"); + apic_disable(); + } + num_processors =3D 1; } } =20 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1397,24 +1397,6 @@ early_param("possible_cpus", _setup_poss { int i, possible; =20 - /* No processor was found in mptable or ACPI MADT */ - if (!num_processors) { - if (boot_cpu_has(X86_FEATURE_APIC)) { - int apicid =3D boot_cpu_physical_apicid; - int cpu =3D read_apic_id(); - - pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu); - - /* Make sure boot cpu is enumerated */ - if (apic->cpu_present_to_apicid(0) =3D=3D BAD_APICID && - apic->apic_id_valid(apicid)) - generic_processor_info(apicid); - } - - if (!num_processors) - num_processors =3D 1; - } - i =3D setup_max_cpus ?: 1; if (setup_possible_cpus =3D=3D -1) { possible =3D num_processors;