From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3AEAA1482F2; Thu, 11 Sep 2025 10:48:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757587717; cv=none; b=p0FRcxOOuo+zNcN//0WRWr8CCgpJ3KLqWjTQrOUgDuY3LdJCkGGixYx2npgkg4vrUqGrHcGXSao0u8Vbkp+PXFh/mtBFlQOuOUI4p6BiD+q9G5ZvqZxgPq2IGpboJgCwES+8RtabkI7jfNtul0ONCk1vKIyix9r7G/NiFIKv7KY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757587717; c=relaxed/simple; bh=DsixxijLlQvnubZxi4JzQTtHQTj0CSjUiFJ3c+Ght1M=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=aHGQxNbJHWeP2gXY0I5fovlgSRBqP6sQaOgP7TmsTRGSkRa5/pwiW216Wpe2AZN8s7ofjEBzgZpsi1RNjIJCGl6X2GrsP3mjVsM6IGaaKyBD27l7VT9JU++QwHiytx0CI5Vv3v+kxzqa4eSh5AAaS95JxGN2cx9AotXZ7NQvZ/M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.216]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4cMvLq3F3rz6L5WM; Thu, 11 Sep 2025 18:44:19 +0800 (CST) Received: from frapeml500008.china.huawei.com (unknown [7.182.85.71]) by mail.maildlp.com (Postfix) with ESMTPS id C88241402F5; Thu, 11 Sep 2025 18:48:32 +0800 (CST) Received: from localhost (10.203.177.15) by frapeml500008.china.huawei.com (7.182.85.71) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Thu, 11 Sep 2025 12:48:31 +0200 Date: Thu, 11 Sep 2025 11:48:30 +0100 From: Jonathan Cameron To: James Morse CC: , , , D Scott Phillips OS , , , , , , Jamie Iles , Xin Hao , , , , David Hildenbrand , Dave Martin , Koba Ko , Shanker Donthineni , , , Rob Herring , Rohit Mathew , "Rafael Wysocki" , Len Brown , Lorenzo Pieralisi , Hanjun Guo , Sudeep Holla , Catalin Marinas , "Will Deacon" , Greg Kroah-Hartman , Danilo Krummrich Subject: Re: [PATCH v2 01/29] ACPI / PPTT: Add a helper to fill a cpumask from a processor container Message-ID: <20250911114830.00002930@huawei.com> In-Reply-To: <20250911114337.0000487e@huawei.com> References: <20250910204309.20751-1-james.morse@arm.com> <20250910204309.20751-2-james.morse@arm.com> <20250911114337.0000487e@huawei.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml500011.china.huawei.com (7.191.174.215) To frapeml500008.china.huawei.com (7.182.85.71) On Thu, 11 Sep 2025 11:43:37 +0100 Jonathan Cameron wrote: > On Wed, 10 Sep 2025 20:42:41 +0000 > James Morse wrote: > > > The ACPI MPAM table uses the UID of a processor container specified in > > the PPTT to indicate the subset of CPUs and cache topology that can > > access each MPAM System Component (MSC). > > > > This information is not directly useful to the kernel. The equivalent > > cpumask is needed instead. > > > > 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 > > Hi James, > > Sorry I missed v1. Busy few weeks. > > I think one resource leak plus a few suggested changes that > I'm not that bothered about. Ignore the resource leak. I didn't read acpi_get_pptt() properly. No bug there. So consider the comments below, but I'm fine with this as is. Reviewed-by: Jonathan Cameron > > Jonathan > > > > --- > > Changes since v1: > > * Replaced commit message with wording from Dave. > > * Fixed a stray plural. > > * Moved further down in the file to make use of get_pptt() helper. > > * Added a break to exit the loop early. > > > > Changes since RFC: > > * Removed leaf_flag local variable from acpi_pptt_get_cpus_from_container() > > > > 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 | 83 ++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/acpi.h | 3 ++ > > 2 files changed, 86 insertions(+) > > > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > > index 54676e3d82dd..1728545d90b2 100644 > > --- a/drivers/acpi/pptt.c > > +++ b/drivers/acpi/pptt.c > > @@ -817,3 +817,86 @@ int find_acpi_cpu_topology_hetero_id(unsigned int cpu) > > return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE, > > ACPI_PPTT_ACPI_IDENTICAL); > > } > > > +/** > > + * acpi_pptt_get_cpus_from_container() - Populate a cpumask with all CPUs in a > > + * processor container > > + * @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; > > + u32 proc_sz; > > + > > + cpumask_clear(cpus); > > + > > + table_hdr = acpi_get_pptt(); > > This calls acpi_get_table() so you need to put it again or every call > to this leaks a reference count. I messed around with DEFINE_FREE() for this > but it doesn't fit that well as the underlying call doesn't return the table. > This one does though so you could do a pptt specific one. > > Or just acpi_put_table(table_hdr); at exit path from this function. > > > > + if (!table_hdr) > > + 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)); > Hmm. Not related to this patch but I have no idea why acpi_get_pptt() > doesn't return a struct acpi_table_pptt as if it did this would be a simple > + 1 and not require those who only sometimes deal with ACPI code to go > check what that macro actually does! > > > > + proc_sz = sizeof(struct acpi_pptt_processor); > Maybe sizeof (*cpu_node) is more helpful to reader. > Also shorter so you could do > while ((unsigned long)entry + sizeof(*cpu_node) <= table_end) > > > + while ((unsigned long)entry + proc_sz <= table_end) { > > + cpu_node = (struct acpi_pptt_processor *)entry; > > For me, assigning this before checking the type is inelegant. > but the nesting does get deep without it so I guess this is ok maybe, though > I wonder if better reorganized to combine a different bunch of conditions. > I think this is functionally identival. > > if (entry->type == ACPI_PTT_TYPE_PROCESSOR) { > struct acpi_pptt_processor *cpu_node = > (struct acpi_pptt_processor *)entry; > if ((cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID) && > (!acpi_pptt_leaf_node(table_hdr, cpu_node) && > (cpu_node->acpi_processor_id == acpi_cpu_id)) { > acpi_pptt_get_child_cpus(table_hdr, cpu_node, cpus); > break; > > } > } > entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry, > entry->length); > > More generally I wonder if it is worth adding a for_each_acpi_pptt_entry() macro. > There is some precedence in drivers acpi such as for_each_nhlt_endpoint() > > That's probably material for another day though unless you think it brings > enough benefits to do it here. > > > > + if (entry->type == ACPI_PPTT_TYPE_PROCESSOR && > > + cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID) { > > + if (!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); > > + break; > > + } > > + } > > + } > > + entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry, > > + entry->length); > > + } > > +} > > 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); >