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 187E3EEAA45 for ; Thu, 14 Sep 2023 14:31:50 +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=Lgyw2IGCo4U4umpAL3ret/+GTX6976NBmKqVIia17cc=; b=e2fQIh+Win100J F9Vovw4JzodPeBev8lBY5OjALv07veDOPr1UYDuUVq9/LPrPCYglFG+xqlqr4biwzA/u8K10X8Rgx NLyOnLnISCWmVPDtGfGCvm2PCtg1/fnhWzA7MmmureD2zn1fyKG4nPyDnySLIuMT8NXeDIgrSlOIr PPQXm5F5vzL4Ro8z3X4mC08RkfRb+0Giezn01Q2qE336Ep2Gq/fiKcUlY9nI8D3prCo+kF2yKVrrN AjilhRtPlmeEiqhhr5doq80IXgQYq/h/pFhVwbEY5fpd/pH7gfn6AT7qlBfNj5HlYAjD3BV2kg0wq 1hQAA/8MtzUegoFQif1w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgnNJ-008dq1-1u; Thu, 14 Sep 2023 14:31:21 +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 1qgnNG-008dop-1N; Thu, 14 Sep 2023 14:31:20 +0000 Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Rmfqw1fxwz6FGNN; Thu, 14 Sep 2023 22:30:36 +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 15:31:11 +0100 Date: Thu, 14 Sep 2023 15:31:10 +0100 From: Jonathan Cameron To: James Morse CC: , , , , , , , , , Salil Mehta , Russell King , Jean-Philippe Brucker , , Subject: Re: [RFC PATCH v2 22/35] ACPI: Check _STA present bit before making CPUs not present Message-ID: <20230914153110.00003e38@Huawei.com> In-Reply-To: <20230913163823.7880-23-james.morse@arm.com> References: <20230913163823.7880-1-james.morse@arm.com> <20230913163823.7880-23-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: lhrpeml100002.china.huawei.com (7.191.160.241) 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_073118_748999_A20E8906 X-CRM114-Status: GOOD ( 27.91 ) 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 16:38:10 +0000 James Morse wrote: > When called acpi_processor_post_eject() unconditionally make a CPU > not-present and unregisters it. > > To add support for AML events where the CPU has become disabled, but > remains present, the _STA method should be checked before calling > acpi_processor_remove(). > > Rename acpi_processor_post_eject() acpi_processor_remove_possible(), and > check the _STA before calling. > > Adding the function prototype for arch_unregister_cpu() allows the > preprocessor guards to be removed. > > After this change CPUs will remain registered and visible to > user-space as offline if buggy firmware triggers an eject-request, > but doesn't clear the corresponding _STA bits after _EJ0 has been > called. Will be fun to see how many such buggy firmwares are out there. > > Signed-off-by: James Morse Comment inline but not directly related to this patch so with or without that change Reviewed-by: Jonathan Cameron > --- > drivers/acpi/acpi_processor.c | 31 +++++++++++++++++++++++++------ > include/linux/cpu.h | 1 + > 2 files changed, 26 insertions(+), 6 deletions(-) > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > index 00dcc23d49a8..2cafea1edc24 100644 > --- a/drivers/acpi/acpi_processor.c > +++ b/drivers/acpi/acpi_processor.c > @@ -457,13 +457,12 @@ static int acpi_processor_add(struct acpi_device *device, > return result; > } > > -#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU > /* Removal */ > -static void acpi_processor_post_eject(struct acpi_device *device) > +static void acpi_processor_make_not_present(struct acpi_device *device) > { > struct acpi_processor *pr; > > - if (!device || !acpi_driver_data(device)) > + if (!IS_ENABLED(CONFIG_ACPI_HOTPLUG_PRESENT_CPU)) Would it be possible to do all the ifdef to IS_ENABLED changes in a separate patch? I haven't figure out if any of them have dependencies on the other changes, but they do create a bunch of noise I'd rather not see in the more complex corners of this. > return; > > pr = acpi_driver_data(device); > @@ -501,7 +500,29 @@ static void acpi_processor_post_eject(struct acpi_device *device) > free_cpumask_var(pr->throttling.shared_cpu_map); > kfree(pr); > } > -#endif /* CONFIG_ACPI_HOTPLUG_PRESENT_CPU */ > + > +static void acpi_processor_post_eject(struct acpi_device *device) > +{ > + struct acpi_processor *pr; > + unsigned long long sta; > + acpi_status status; > + > + if (!device) > + return; > + > + pr = acpi_driver_data(device); > + if (!pr || pr->id >= nr_cpu_ids || invalid_phys_cpuid(pr->phys_id)) > + return; > + > + status = acpi_evaluate_integer(pr->handle, "_STA", NULL, &sta); > + if (ACPI_FAILURE(status)) > + return; > + > + if (cpu_present(pr->id) && !(sta & ACPI_STA_DEVICE_PRESENT)) { > + acpi_processor_make_not_present(device); > + return; > + } > +} > > #ifdef CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC > bool __init processor_physically_present(acpi_handle handle) > @@ -626,9 +647,7 @@ static const struct acpi_device_id processor_device_ids[] = { > static struct acpi_scan_handler processor_handler = { > .ids = processor_device_ids, > .attach = acpi_processor_add, > -#ifdef CONFIG_ACPI_HOTPLUG_PRESENT_CPU > .post_eject = acpi_processor_post_eject, > -#endif > .hotplug = { > .enabled = true, > }, > diff --git a/include/linux/cpu.h b/include/linux/cpu.h > index a71691d7c2ca..e117c06e0c6b 100644 > --- a/include/linux/cpu.h > +++ b/include/linux/cpu.h > @@ -81,6 +81,7 @@ struct device *cpu_device_create(struct device *parent, void *drvdata, > const struct attribute_group **groups, > const char *fmt, ...); > extern int arch_register_cpu(int cpu); > +extern void arch_unregister_cpu(int cpu); > #ifdef CONFIG_HOTPLUG_CPU > extern void unregister_cpu(struct cpu *cpu); > extern ssize_t arch_cpu_probe(const char *, size_t); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel