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 X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3016C004C9 for ; Sun, 5 May 2019 07:10:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBF7620881 for ; Sun, 5 May 2019 07:10:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726310AbfEEHKp (ORCPT ); Sun, 5 May 2019 03:10:45 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:41056 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725792AbfEEHKp (ORCPT ); Sun, 5 May 2019 03:10:45 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 0CDC92711EA03533A31B; Sun, 5 May 2019 15:10:42 +0800 (CST) Received: from [127.0.0.1] (10.177.19.180) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Sun, 5 May 2019 15:10:33 +0800 Subject: Re: [PATCH v3 2/5] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens To: Jeremy Linton , CC: , , , , , , , , References: <20190503232407.37195-1-jeremy.linton@arm.com> <20190503232407.37195-3-jeremy.linton@arm.com> From: Kefeng Wang Message-ID: Date: Sun, 5 May 2019 15:09:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <20190503232407.37195-3-jeremy.linton@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.177.19.180] X-CFilter-Loop: Reflected Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Message-ID: <20190505070901.AqqwQ0SFxag6BDuokrQP_6gSQvESTtNsTWTn6DWVHzs@z> On 2019/5/4 7:24, Jeremy Linton wrote: > ACPI 6.3 adds a flag to indicate that child nodes are all > identical cores. This is useful to authoritatively determine > if a set of (possibly offline) cores are identical or not. > > Since the flag doesn't give us a unique id we can generate > one and use it to create bitmaps of sibling nodes, or simply > in a loop to determine if a subset of cores are identical. > > Signed-off-by: Jeremy Linton > --- > drivers/acpi/pptt.c | 26 ++++++++++++++++++++++++++ > include/linux/acpi.h | 5 +++++ > 2 files changed, 31 insertions(+) > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index 83a026765faa..1865515297ca 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -660,3 +660,29 @@ int find_acpi_cpu_topology_package(unsigned int cpu) > return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE, > ACPI_PPTT_PHYSICAL_PACKAGE); > } > + > +/** > + * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag > + * @cpu: Kernel logical CPU number > + * > + * Determine a unique heterogeneous tag for the given CPU. CPUs with the same > + * implementation should have matching tags. > + * > + * The returned tag can be used to group peers with identical implementation. > + * > + * The search terminates when a level is found with the identical implementation > + * flag set or we reach a root node. > + * > + * Due to limitations in the PPTT data structure, there may be rare situations > + * where two cores in a heterogeneous machine may be identical, but won't have > + * the same tag. > + * > + * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found. > + * Otherwise returns a value which represents a group of identical cores > + * similar to this CPU. > + */ > +int find_acpi_cpu_topology_hetero_id(unsigned int cpu) > +{ > + return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE, > + ACPI_PPTT_ACPI_IDENTICAL); > +} > diff --git a/include/linux/acpi.h b/include/linux/acpi.h > index d5dcebd7aad3..1444fb042898 100644 > --- a/include/linux/acpi.h > +++ b/include/linux/acpi.h > @@ -1309,6 +1309,7 @@ static inline int lpit_read_residency_count_address(u64 *address) > #ifdef CONFIG_ACPI_PPTT > int find_acpi_cpu_topology(unsigned int cpu, int level); > int find_acpi_cpu_topology_package(unsigned int cpu); > +int find_acpi_cpu_topology_hetero_id(unsigned int cpu); > int find_acpi_cpu_cache_topology(unsigned int cpu, int level); > #else > static inline int find_acpi_cpu_topology(unsigned int cpu, int level) > @@ -1319,6 +1320,10 @@ static inline int find_acpi_cpu_topology_package(unsigned int cpu) > { > return -EINVAL; > } static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu) > +static int find_acpi_cpu_topology_hetero_id(unsigned int cpu) > +{ > + return -EINVAL; > +} > static inline int find_acpi_cpu_cache_topology(unsigned int cpu, int level) > { > return -EINVAL;