From nobody Sat Oct 4 00:22:22 2025 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 048F9221714; Fri, 22 Aug 2025 15:31:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755876685; cv=none; b=It0ftigCLqDWHxpR84dA9ViouHjce/qgKCRP2J3hp0Vr6DmHdcOz47iGfgjFx7+DmholAWwXGtzF5ixWn0YkXXsUc104931RI3IWX4NgJiWoEh0xDuHroYP+pW55bSLl6tcCAIwERmnJ8f90t8D5nhwJEGdgRJMsmjma+Iycths= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755876685; c=relaxed/simple; bh=gEyQcZZsP23ow9G5sDRvS21MvQKVxhDWe31++cbp5L0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=sP8oyJMfPQm6+n7shkHVrsMHnAHnRictJjImCglzBYzFQoBKiK0qdB/pHibzMgJpqcKcjBqpIZ9dXzJ6YmJMCKFttcznJeFS1VJxPp2CEJDtFKPjAqkrtcGaLvny10swd+DTKGZ7I13B5Gt+XPOyLyP7v+8onlbPUhooK0vmZ6E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com 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 0F6E327DC; Fri, 22 Aug 2025 08:31:15 -0700 (PDT) Received: from merodach.members.linode.com (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EDF8F3F63F; Fri, 22 Aug 2025 08:31:17 -0700 (PDT) From: James Morse To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, devicetree@vger.kernel.org Cc: James Morse , 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 Subject: [PATCH 03/33] ACPI / PPTT: Add a helper to fill a cpumask from a processor container Date: Fri, 22 Aug 2025 15:29:44 +0000 Message-Id: <20250822153048.2287-4-james.morse@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20250822153048.2287-1-james.morse@arm.com> References: <20250822153048.2287-1-james.morse@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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; } =20 +/** + * acpi_pptt_get_child_cpus() - Find all the CPUs below a PPTT processor n= ode + * @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 =3D get_acpi_id_for_cpu(cpu); + cpu_node =3D acpi_find_processor_node(table_hdr, acpi_id); + + while (cpu_node) { + if (cpu_node =3D=3D parent_node) { + cpumask_set_cpu(cpu, cpus); + break; + } + cpu_node =3D 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 =3D acpi_get_table(ACPI_SIG_PPTT, 0, &table_hdr); + if (ACPI_FAILURE(status)) + return; + + table_end =3D (unsigned long)table_hdr + table_hdr->length; + entry =3D ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr, + sizeof(struct acpi_table_pptt)); + proc_sz =3D sizeof(struct acpi_pptt_processor); + while ((unsigned long)entry + proc_sz <=3D table_end) { + cpu_node =3D (struct acpi_pptt_processor *)entry; + if (entry->type =3D=3D ACPI_PPTT_TYPE_PROCESSOR && + cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID) { + leaf_flag =3D acpi_pptt_leaf_node(table_hdr, cpu_node); + if (!leaf_flag) { + if (cpu_node->acpi_processor_id =3D=3D acpi_cpu_id) + acpi_pptt_get_child_cpus(table_hdr, cpu_node, cpus); + } + } + entry =3D 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 leve= l); 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(un= signed int cpu) { return -EINVAL; } +static inline void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, + cpumask_t *cpus) { } #endif =20 void acpi_arch_init(void); --=20 2.20.1