From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1F3512E175E for ; Thu, 26 Jun 2025 17:11:01 +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=1750957863; cv=none; b=jh0nelOE88ubYGGDRcfZbUj0tFOXusJCmUZbk7ovh+FMIiEpIkufxxCrJvRI3ZLjSfkIQheQzzQGrzx3fcaUwyPoo6bUaj4mK51uOQ7IoBqjB5mP7DNJ7u/Ii2iAAernRMEhUt0WIzSYUFe0M2a27crXfAveVPqLkYxVpcwkJ1Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750957863; c=relaxed/simple; bh=GTHCDg10NkCrXnbYrkMEXqEPFTmHMkSB5GlKM6np4iE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CL/qTAgzvd11PWqgQdYZlQCc3Mci+QRoJLGDUbnW7abr6k8qHFz+jR5kkVlRAXwL4WkOsD8kI0YlWMz3n/7MLAbWe+XedvhPSrkN03kNL0N0suifsLpuLpvUEkEHy0FMNqINmsYVXY502eHTf/jVBugDHI/UUklMQE6HOqXiY5s= 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 996571758; Thu, 26 Jun 2025 10:10:43 -0700 (PDT) Received: from [10.1.197.43] (eglon.cambridge.arm.com [10.1.197.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4325F3F762; Thu, 26 Jun 2025 10:11:00 -0700 (PDT) Message-ID: Date: Thu, 26 Jun 2025 18:10:58 +0100 Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] ACPI / PPTT: Add a helper to fill a cpumask from a processor container To: linux-acpi@vger.kernel.org Cc: Rafael Wysocki , Len Brown , sudeep.holla@arm.com, jeremy.linton@arm.com, Dave P Martin References: <20250612171336.4858-1-james.morse@arm.com> <20250612171336.4858-2-james.morse@arm.com> Content-Language: en-GB From: James Morse In-Reply-To: <20250612171336.4858-2-james.morse@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hello! (CC: +Dave Martin) On 12/06/2025 18:13, 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. > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index 54676e3d82dd..aaf9b5a26d07 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -298,6 +298,97 @@ static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_he > +/** > + * 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) { Dave Martin picked out an off-by-one here - this pattern was copied from other functions, then fixed while I was still lugging this around out of tree. Should be: | while ((unsigned long)entry + proc_sz <= table_end) { See adfab6b39202481bb43286fff94def4953793fdb. I've fixed this locally. > + 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); > + } > + } > + entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry, > + entry->length); > + } > + > + acpi_put_table(table_hdr); > + > + return ret; > +} Thanks, James