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 3C25EC83F1A for ; Wed, 23 Jul 2025 15:11:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LjtQVgyC6aebje4X9xjGXGD8jOjCq+st2YHAXeZLavs=; b=ENZZD3VfK88MVWKs6Qp9Aj1yho Kg/IyC9TzMRR/WPH/g8dUp1HI0qBFBKOjAA04H1zwxoXtdIK8MGhar/TPfXQnIvu0J6tTaGqolSVd Eo7KeW03nwCYZ9L4YCJ7Yg7mPXLSYtwh7IcA7q1AQE90+SnXJ5RY9COQH9bWyKMHpvpGd0RNtLHFa pihWSb3JnvSQEfug74KCv6aVDnbep7E7TyjfAeu/3xY1mj+fBexlvp6srRbNoKDQ5dl0RM7Vq/CCp duM9MukNLJqp9WeeXe+Q/5OJyV5F26FG2ZYm2rv1YSUO0ASPTRnemsSSwMcKDT7dpgGkr3riN3EMp 4YhNYF/w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueb7k-00000005LHV-1cYx; Wed, 23 Jul 2025 15:11:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ueagP-00000005EmI-3TZ5 for linux-arm-kernel@lists.infradead.org; Wed, 23 Jul 2025 14:43:03 +0000 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 6394322C7; Wed, 23 Jul 2025 07:42:52 -0700 (PDT) Received: from [10.1.196.46] (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8C6003F6A8; Wed, 23 Jul 2025 07:42:54 -0700 (PDT) Message-ID: <46e3ead8-411d-4e51-b38b-da791e568b94@arm.com> Date: Wed, 23 Jul 2025 15:42:52 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 05/36] ACPI / PPTT: Add a helper to fill a cpumask from a processor container To: James Morse , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Rob Herring , Rohit Mathew , Shanker Donthineni , Zeng Heng , Lecopzer Chen , Carl Worth , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com, David Hildenbrand , Rex Nie , Dave Martin , Koba Ko , Sudeep Holla References: <20250711183648.30766-1-james.morse@arm.com> <20250711183648.30766-6-james.morse@arm.com> Content-Language: en-US From: Ben Horgan In-Reply-To: <20250711183648.30766-6-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250723_074301_964877_89D11F76 X-CRM114-Status: GOOD ( 28.88 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi James, On 7/11/25 19:36, James Morse wrote: > The PPTT describes CPUs and caches, as well as processor containers. > The ACPI table for MPAM describes the set of CPUs that can access an MSC > with the UID of a processor container. > > Add a helper to find the processor container by its id, then walk > the possible CPUs to fill a cpumask with the CPUs that have this > processor container as a parent. > > CC: Dave Martin > Reviewed-by: Sudeep Holla > Signed-off-by: James Morse > --- > drivers/acpi/pptt.c | 93 ++++++++++++++++++++++++++++++++++++++++++++ > include/linux/acpi.h | 6 +++ > 2 files changed, 99 insertions(+) > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index 54676e3d82dd..13619b1b821b 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -298,6 +298,99 @@ static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_he > return NULL; > } > > +/** > + * acpi_pptt_get_child_cpus() - Find all the CPUs below a PPTT processor node > + * @table_hdr: A reference to the PPTT table. > + * @parent_node: A pointer to the processor node in the @table_hdr. > + * @cpus: A cpumask to fill with the CPUs below @parent_node. > + * > + * Walks up the PPTT from every possible CPU to find if the provided > + * @parent_node is a parent of this CPU. > + */ > +static void acpi_pptt_get_child_cpus(struct acpi_table_header *table_hdr, > + struct acpi_pptt_processor *parent_node, > + cpumask_t *cpus) > +{ > + struct acpi_pptt_processor *cpu_node; > + u32 acpi_id; > + int cpu; > + > + cpumask_clear(cpus); > + > + for_each_possible_cpu(cpu) { > + acpi_id = get_acpi_id_for_cpu(cpu); > + cpu_node = acpi_find_processor_node(table_hdr, acpi_id); > + > + while (cpu_node) { > + if (cpu_node == parent_node) { > + cpumask_set_cpu(cpu, cpus); > + break; > + } > + cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent); > + } > + } > +} > + > +/** > + * acpi_pptt_get_cpus_from_container() - Populate a cpumask with all CPUs in a > + * processor containers > + * @acpi_cpu_id: The UID of the processor container. > + * @cpus The resulting CPU mask. > + * > + * Find the specified Processor Container, and fill @cpus with all the cpus > + * below it. > + * > + * Not all 'Processor' entries in the PPTT are either a CPU or a Processor > + * Container, they may exist purely to describe a Private resource. CPUs > + * have to be leaves, so a Processor Container is a non-leaf that has the > + * 'ACPI Processor ID valid' flag set. > + * > + * Return: 0 for a complete walk, or an error if the mask is incomplete. > + */ > +int acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus) > +{ > + struct acpi_pptt_processor *cpu_node; > + struct acpi_table_header *table_hdr; > + struct acpi_subtable_header *entry; > + bool leaf_flag, has_leaf_flag = false; > + unsigned long table_end; > + acpi_status status; > + u32 proc_sz; > + int ret = 0; > + > + cpumask_clear(cpus); > + > + status = acpi_get_table(ACPI_SIG_PPTT, 0, &table_hdr); > + if (ACPI_FAILURE(status)) > + return 0; > + > + if (table_hdr->revision > 1) > + has_leaf_flag = true; > + > + table_end = (unsigned long)table_hdr + table_hdr->length; > + entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr, > + sizeof(struct acpi_table_pptt)); > + proc_sz = sizeof(struct acpi_pptt_processor); > + while ((unsigned long)entry + proc_sz <= table_end) { > + cpu_node = (struct acpi_pptt_processor *)entry; > + if (entry->type == ACPI_PPTT_TYPE_PROCESSOR && > + cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID) { > + leaf_flag = cpu_node->flags & ACPI_PPTT_ACPI_LEAF_NODE; > + if ((has_leaf_flag && !leaf_flag) || > + (!has_leaf_flag && !acpi_pptt_leaf_node(table_hdr, cpu_node))) { > + if (cpu_node->acpi_processor_id == acpi_cpu_id) > + acpi_pptt_get_child_cpus(table_hdr, cpu_node, cpus); > + } acpi_pptt_leaf_node() returns early based on the leaf flag so you can just rely on that here; remove has_leaf_flag and the corresponding extra logic. > + } > + entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry, > + entry->length); > + } > + > + acpi_put_table(table_hdr); > + > + return ret; > +} > + > static u8 acpi_cache_type(enum cache_type type) > { > switch (type) { > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index f102c0fe3431..8c3165c2b083 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -1541,6 +1541,7 @@ int find_acpi_cpu_topology(unsigned int cpu, int level); > int find_acpi_cpu_topology_cluster(unsigned int cpu); > int find_acpi_cpu_topology_package(unsigned int cpu); > int find_acpi_cpu_topology_hetero_id(unsigned int cpu); > +int acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus); > #else > static inline int acpi_pptt_cpu_is_thread(unsigned int cpu) > { > @@ -1562,6 +1563,11 @@ static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu) > { > return -EINVAL; > } > +static inline int acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, > + cpumask_t *cpus) > +{ > + return -EINVAL; > +} > #endif > > void acpi_arch_init(void); Thanks, Ben