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 B8F4B1AF0C8; Thu, 28 Aug 2025 15:56:28 +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=1756396591; cv=none; b=GdmOnsNEsyH+5IWcEgYvh298yzFv4bslCRA0AieV1TT2Gkeo9eqETU1FCoGjywZKycw+xaGapTBPQsFZksNGyJHydnTIl8KBFOCibapFsMZBtXk05Et7g2jZyYCQSNQO/GvXTi831/906aipxILIv5flKB4IdIQYX6QBbRWgNDk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756396591; c=relaxed/simple; bh=aSrkqHn+DyGSVPv6u/DJa9AVSHkMifHLrOO6OYspVnw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=LknEpgvsERI8qP6dKIPirq5SWePAxJjx/9PEe7c41QQ1twQoHvTKqK1enSxeHr85pJO2lQGZrtsdvcGzIMf26geWXwh7am5JrP0bWZ/BtgGuLQqyRQh55/MJUj9nDX8vvqw+3RkCuHVOFvIG4GGfgI7SiO8mGG9BEWsclcsQt44= 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 7218E1688; Thu, 28 Aug 2025 08:56:19 -0700 (PDT) Received: from [10.1.196.42] (eglon.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 27D823F694; Thu, 28 Aug 2025 08:56:22 -0700 (PDT) Message-ID: <0de34aa4-359c-4837-916c-88db0b740e39@arm.com> Date: Thu, 28 Aug 2025 16:56:20 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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: Ben Horgan , 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> Content-Language: en-GB From: James Morse In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Ben, On 26/08/2025 15:45, Ben Horgan wrote: > 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. >> 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 >> +/** >> + * 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. Sure, this is a hangover from the earlier cleanup you suggested. It's readable enough without giving the result a name. Thanks, James