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 B06BECA0FE7 for ; Tue, 26 Aug 2025 14:57:02 +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=uTZR7C2pPWoCS/17WJctZ0INl0LEqmKfSETGH+YqyOs=; b=Py6K0qttKIS4uAbL+AFM3ln7kn J6MQrwwrBKbXIyPt7Z3UmQxTdjUAZpsIAvFFXBdu5mXiBrI5T8iJJWjqMben+AjIdTMCMh7P+b4Mh 6z1hJYyjO3nR2o+0nJpDkucoSCx6FBmv8MoC5MNV0qw7YWO85qFZmrlXVImbPPwTrCJtqJ9rAU2AK 09/sf2Lm2oUG/eRFzYeH8NghyNAb4J6W85NAfVUahhGEKqc6ZLbmq2LlaOG9P7JCbEdXcx2sLeO+m +cwnxfZnwJA3YKveFhwboybIOpRc+NIszQ0yOR2is8+KZFM8ftuoLNHUXkEVutyNwUyxe4NE37CAJ 3lBXPGgQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uqv6W-0000000CLfL-2mp1; Tue, 26 Aug 2025 14:56:56 +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 1uquvf-0000000CJWs-3EXa for linux-arm-kernel@lists.infradead.org; Tue, 26 Aug 2025 14:45:45 +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 EF0861F91; Tue, 26 Aug 2025 07:45:32 -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 1305F3F694; Tue, 26 Aug 2025 07:45:35 -0700 (PDT) Message-ID: Date: Tue, 26 Aug 2025 15:45:34 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 03/33] 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, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org Cc: shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, 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 , Shanker Donthineni , fenghuay@nvidia.com, baisheng.gao@unisoc.com, Jonathan Cameron , Rob Herring , Rohit Mathew , Rafael Wysocki , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Greg Kroah-Hartman , Danilo Krummrich References: <20250822153048.2287-1-james.morse@arm.com> <20250822153048.2287-4-james.morse@arm.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <20250822153048.2287-4-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250826_074543_926088_A9929B18 X-CRM114-Status: GOOD ( 28.92 ) 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, The patch logic update makes sense to me. Just a nit. On 8/22/25 16:29, 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 > --- > Changes since RFC: > * Dropped has_leaf_flag dodging of acpi_pptt_leaf_node() > * Added missing : in kernel-doc > * Made helper return void as this never actually returns an error. > --- > drivers/acpi/pptt.c | 86 ++++++++++++++++++++++++++++++++++++++++++++ > include/linux/acpi.h | 3 ++ > 2 files changed, 89 insertions(+) > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index 54676e3d82dd..4791ca2bdfac 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -298,6 +298,92 @@ 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. > + */ > +void 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; > + unsigned long table_end; > + acpi_status status; > + bool leaf_flag; > + u32 proc_sz; > + > + cpumask_clear(cpus); > + > + status = acpi_get_table(ACPI_SIG_PPTT, 0, &table_hdr); > + if (ACPI_FAILURE(status)) > + return; > + > + 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 = acpi_pptt_leaf_node(table_hdr, cpu_node); nit: Consider dropping the boolean leaf_flag and just using acpi_pptt_leaf_node() in the condition. The name leaf_flag is slightly overloaded to include the case when the acpi leaf flag is not supported and dropping it would make the code more succinct. > + if (!leaf_flag) { > + if (cpu_node->acpi_processor_id == acpi_cpu_id) > + acpi_pptt_get_child_cpus(table_hdr, cpu_node, cpus); > + } > + } > + entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry, > + entry->length); > + } > + > + acpi_put_table(table_hdr); > +} > + > static u8 acpi_cache_type(enum cache_type type) > { > switch (type) { > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index 1c5bb1e887cd..f97a9ff678cc 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); > +void 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 +1563,8 @@ static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu) > { > return -EINVAL; > } > +static inline void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, > + cpumask_t *cpus) { } > #endif > > void acpi_arch_init(void); Thanks, Ben