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 92975CF3188 for ; Wed, 19 Nov 2025 10:00:58 +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=WQS2sp0fRfTQw4poTmyaR57P0BUIOJZcl4gCJY+80aY=; b=WUtCxEJPP+gF15HlaHlgiz0duA hhDFr/F7wSylZtlmFLGk3/hMXSYFSiwHEjY1tEuNX6405V9XldyC+QWhSKcpO8Y2xgmd36aWUKiyg Z5j1MkuqtHoDZihBWi9Uoko9ZLE3NUt6TOM7oW+IRgChbvYF3AGCUSGw2rjQOjSKdCLZbJ6YvSvly 7GDB1w/KYyRA0TheRQpfiU7u8xkxSzLFAEwgFpPbxQ35nzv+0h35AjJv9lpEDIpOuIRh89exIxIoD B12gZjpp86/LxxIR4eLuMk8Ygwb9yKze4tq348szZnYp7rqqJ9bQ3F8uUFSaZ856G5DOeFU3H3XYr c1Gdkydw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLezY-00000002uiI-1q5l; Wed, 19 Nov 2025 10:00:48 +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 1vLezU-00000002uht-3fFq for linux-arm-kernel@lists.infradead.org; Wed, 19 Nov 2025 10:00:46 +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 76950FEC; Wed, 19 Nov 2025 02:00:33 -0800 (PST) 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 336103F740; Wed, 19 Nov 2025 02:00:36 -0800 (PST) Message-ID: <6eaf7e9c-a833-44c8-a213-7247a47d417d@arm.com> Date: Wed, 19 Nov 2025 10:00:34 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 01/34] ACPI / PPTT: Add a helper to fill a cpumask from a processor container To: Gavin Shan , james.morse@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, bobo.shaobowang@huawei.com, carl@os.amperecomputing.com, catalin.marinas@arm.com, dakr@kernel.org, dave.martin@arm.com, david@redhat.com, dfustini@baylibre.com, fenghuay@nvidia.com, gregkh@linuxfoundation.org, guohanjun@huawei.com, jeremy.linton@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, lenb@kernel.org, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lpieralisi@kernel.org, peternewman@google.com, quic_jiles@quicinc.com, rafael@kernel.org, robh@kernel.org, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, sudeep.holla@arm.com, tan.shaopeng@fujitsu.com, will@kernel.org, xhao@linux.alibaba.com, Shaopeng Tan , Zeng Heng References: <20251117170014.4113754-1-ben.horgan@arm.com> <20251117170014.4113754-2-ben.horgan@arm.com> <455c577a-2c6b-4d57-9547-8f55bfe1c126@redhat.com> From: Ben Horgan Content-Language: en-US In-Reply-To: <455c577a-2c6b-4d57-9547-8f55bfe1c126@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251119_020045_009456_26CD82E2 X-CRM114-Status: GOOD ( 25.11 ) 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 Gavin, On 11/19/25 03:35, Gavin Shan wrote: > Hi Ben, > > On 11/18/25 2:59 AM, Ben Horgan wrote: >> From: James Morse >> >> 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 >> Reviewed-by: Jonathan Cameron >> Reviewed-by: Fenghua Yu >> Reviewed-by: Gavin Shan >> Reviewed-by: Shaopeng Tan >> Tested-by: Fenghua Yu >> Tested-by: Shaopeng Tan >> Tested-by: Peter Newman >> Tested-by: Carl Worth >> Tested-by: Gavin Shan >> Tested-by: Zeng Heng >> Signed-off-by: James Morse >> Signed-off-by: Ben Horgan >> --- >> Changes since v4: >> Remove blank line >> >> Changes since v3: >> Refer to processor hierarchy in comments (Jonathan) >> Fix indent (Jonathan) >> --- >>   drivers/acpi/pptt.c  | 84 ++++++++++++++++++++++++++++++++++++++++++++ >>   include/linux/acpi.h |  3 ++ >>   2 files changed, 87 insertions(+) >> > > Since this series may need another respin, a nitpick below... > >> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c >> index 54676e3d82dd..b8248c0092fe 100644 >> --- a/drivers/acpi/pptt.c >> +++ b/drivers/acpi/pptt.c >> @@ -817,3 +817,87 @@ 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_child_cpus() - Find all the CPUs below a PPTT >> + * processor hierarchy node >> + * >> + * @table_hdr:        A reference to the PPTT table >> + * @parent_node:    A pointer to the processor hierarchy 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); >> + > > The CPU mask has been cleared in its only caller > acpi_pptt_get_cpus_from_container(), > no need to clear it again. I'd rather not change this as it adds extra constraints on the caller which aren't necessarily expected. > >> +    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 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 Hierarchy' 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. >> + */ >> +void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus) >> +{ >> +    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(); >> +    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)); >> +    proc_sz = sizeof(struct acpi_pptt_processor); >> +    while ((unsigned long)entry + proc_sz <= table_end) { >> +        if (entry->type == ACPI_PPTT_TYPE_PROCESSOR) { >> +            struct acpi_pptt_processor *cpu_node; >> + >> +            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); >> +    } >> +} >> diff --git a/include/linux/acpi.h b/include/linux/acpi.h >> index 5ff5d99f6ead..4752ebd48132 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, > Gavin > Thanks, Ben