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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A4318EEAA40 for ; Thu, 14 Sep 2023 13:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:CC:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=c9ow4zgZglZx96NaXa/qqN0OrXxnVs/toaiqs8FGRRQ=; b=ENK7rxixnETUN2 oiucazNAPjomEVllyMgpbblku7wlDF10tBjELUVf9qjCPUR4EJhffofndYKz+F93luroOLHFQNP8A ktxzffcxdJVDB0K42F2M5ySlF78fIBTMoPqvHZlfRMlmkaYjVvkeh1EZ1fAdqruBZVrIT/frlzWAX Ze6c90ZHWg7LFp4Kz8Yo9Blrga9tTcVjWcJtPmLr5QKiM2Wm3Nt6Of6Mdw+IYS7NCABFJ5u3p1n4j NuCqBAVB9W/2/F6qh6K261sYdwnToll/9pDOKFsjPQEl9B9o7No6yzBNQxUcGV+2b3fIM8YRXizRm 5bqpTEL71g9Kais0/Gxw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgmpK-008Z3a-2x; Thu, 14 Sep 2023 13:56:14 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qgmpI-008Z2m-03; Thu, 14 Sep 2023 13:56:13 +0000 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rmf2700D8z6HJb0; Thu, 14 Sep 2023 21:54:22 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Thu, 14 Sep 2023 14:56:08 +0100 Date: Thu, 14 Sep 2023 14:56:07 +0100 From: Jonathan Cameron To: James Morse CC: , , , , , , , , , Salil Mehta , Russell King , Jean-Philippe Brucker , , Subject: Re: [RFC PATCH v2 16/35] ACPI: processor: Register CPUs that are online, but not described in the DSDT Message-ID: <20230914145607.00006f9b@Huawei.com> In-Reply-To: <20230913163823.7880-17-james.morse@arm.com> References: <20230913163823.7880-1-james.morse@arm.com> <20230913163823.7880-17-james.morse@arm.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230914_065612_193479_FD0F9DAA X-CRM114-Status: GOOD ( 23.02 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 13 Sep 2023 16:38:04 +0000 James Morse wrote: > ACPI has two descriptions of CPUs, one in the MADT/APIC table, the other > in the DSDT. Both are required. (ACPI 6.5's 8.4 "Declaring Processors" > says "Each processor in the system must be declared in the ACPI > namespace"). Having two descriptions allows firmware authors to get > this wrong. > > If CPUs are described in the MADT/APIC, they will be brought online > early during boot. Once the register_cpu() calls are moved to ACPI, > they will be based on the DSDT description of the CPUs. When CPUs are > missing from the DSDT description, they will end up online, but not > registered. > > Add a helper that runs after acpi_init() has completed to register > CPUs that are online, but weren't found in the DSDT. Any CPU that > is registered by this code triggers a firmware-bug warning and kernel > taint. > > Qemu TCG only describes the first CPU in the DSDT, unless cpu-hotplug > is configured. We should fix that as who likes warnings and taint :) I dread to think how common this will turn out to be. > > Signed-off-by: James Morse LGTM Reviewed-by: Jonathan Cameron > --- > drivers/acpi/acpi_processor.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > index b4bde78121bb..a01e315aa16a 100644 > --- a/drivers/acpi/acpi_processor.c > +++ b/drivers/acpi/acpi_processor.c > @@ -790,6 +790,25 @@ void __init acpi_processor_init(void) > acpi_pcc_cpufreq_init(); > } > > +static int __init acpi_processor_register_missing_cpus(void) > +{ > + int cpu; > + > + if (acpi_disabled) > + return 0; > + > + for_each_online_cpu(cpu) { > + if (!get_cpu_device(cpu)) { > + pr_err_once(FW_BUG "CPU %u has no ACPI namespace description!\n", cpu); > + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); > + arch_register_cpu(cpu); > + } > + } > + > + return 0; > +} > +subsys_initcall_sync(acpi_processor_register_missing_cpus); > + > #ifdef CONFIG_ACPI_PROCESSOR_CSTATE > /** > * acpi_processor_claim_cst_control - Request _CST control from the platform. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel