From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Linton Subject: Re: [PATCH v3 2/5] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens Date: Tue, 7 May 2019 13:26:28 -0500 Message-ID: References: <20190503232407.37195-1-jeremy.linton@arm.com> <20190503232407.37195-3-jeremy.linton@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Kefeng Wang , linux-arm-kernel@lists.infradead.org Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, rjw@rjwysocki.net, linuxarm@huawei.com, linux-acpi@vger.kernel.org, sudeep.holla@arm.com, lenb@kernel.org List-Id: linux-acpi@vger.kernel.org Hi, On 5/5/19 2:09 AM, Kefeng Wang wrote: > > 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) Yes, good catch, I just saw that warning. >> +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; > 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,URIBL_BLOCKED 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 C09BAC004C9 for ; Tue, 7 May 2019 18:26:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A088D205C9 for ; Tue, 7 May 2019 18:26:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727006AbfEGS0h (ORCPT ); Tue, 7 May 2019 14:26:37 -0400 Received: from foss.arm.com ([217.140.101.70]:33598 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726476AbfEGS0h (ORCPT ); Tue, 7 May 2019 14:26:37 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E214915AB; Tue, 7 May 2019 11:26:36 -0700 (PDT) Received: from [192.168.100.241] (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B5A013F5AF; Tue, 7 May 2019 11:26:35 -0700 (PDT) Subject: Re: [PATCH v3 2/5] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens To: Kefeng Wang , linux-arm-kernel@lists.infradead.org Cc: mark.rutland@arm.com, lorenzo.pieralisi@arm.com, will.deacon@arm.com, sudeep.holla@arm.com, rjw@rjwysocki.net, linuxarm@huawei.com, linux-acpi@vger.kernel.org, catalin.marinas@arm.com, lenb@kernel.org References: <20190503232407.37195-1-jeremy.linton@arm.com> <20190503232407.37195-3-jeremy.linton@arm.com> From: Jeremy Linton Message-ID: Date: Tue, 7 May 2019 13:26:28 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format="flowed" Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Message-ID: <20190507182628.xTIK-jGj4VA-CWC5qwgafJ_mVicdLdpG3mmZIZm62cc@z> Hi, On 5/5/19 2:09 AM, Kefeng Wang wrote: > > 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) Yes, good catch, I just saw that warning. >> +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; >