From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751990AbeAPUW1 (ORCPT + 1 other); Tue, 16 Jan 2018 15:22:27 -0500 Received: from foss.arm.com ([217.140.101.70]:60728 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751117AbeAPUWZ (ORCPT ); Tue, 16 Jan 2018 15:22:25 -0500 Subject: Re: [PATCH v6 05/12] ACPI/PPTT: Add Processor Properties Topology Table parsing To: Sudeep Holla Cc: linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, hanjun.guo@linaro.org, lorenzo.pieralisi@arm.com, rjw@rjwysocki.net, will.deacon@arm.com, catalin.marinas@arm.com, gregkh@linuxfoundation.org, viresh.kumar@linaro.org, mark.rutland@arm.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, jhugo@codeaurora.org, wangxiongfeng2@huawei.com, Jonathan.Zhang@cavium.com, ahs3@redhat.com, Jayachandran.Nair@cavium.com, austinwc@codeaurora.org, lenb@kernel.org, vkilari@codeaurora.org, morten.rasmussen@arm.com References: <20180113005920.28658-1-jeremy.linton@arm.com> <20180113005920.28658-6-jeremy.linton@arm.com> <20180115154813.GB17664@e107155-lin> From: Jeremy Linton Message-ID: <096cdff0-d160-68ba-4cd2-0691dd04eac6@arm.com> Date: Tue, 16 Jan 2018 14:22:22 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <20180115154813.GB17664@e107155-lin> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Hi, On 01/15/2018 09:48 AM, Sudeep Holla wrote: > On Fri, Jan 12, 2018 at 06:59:13PM -0600, Jeremy Linton wrote: >> ACPI 6.2 adds a new table, which describes how processing units >> are related to each other in tree like fashion. Caches are >> also sprinkled throughout the tree and describe the properties >> of the caches in relation to other caches and processing units. >> >> Add the code to parse the cache hierarchy and report the total >> number of levels of cache for a given core using >> acpi_find_last_cache_level() as well as fill out the individual >> cores cache information with cache_setup_acpi() once the >> cpu_cacheinfo structure has been populated by the arch specific >> code. >> >> An additional patch later in the set adds the ability to report >> peers in the topology using find_acpi_cpu_topology() >> to report a unique ID for each processing unit at a given level >> in the tree. These unique id's can then be used to match related >> processing units which exist as threads, COD (clusters >> on die), within a given package, etc. >> >> Signed-off-by: Jeremy Linton >> --- >> drivers/acpi/pptt.c | 476 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 476 insertions(+) >> create mode 100644 drivers/acpi/pptt.c >> >> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c >> new file mode 100644 >> index 000000000000..2c4b3ed862a8 >> --- /dev/null >> +++ b/drivers/acpi/pptt.c >> @@ -0,0 +1,476 @@ >> +/* >> + * Copyright (C) 2018, ARM >> + * >> + * This program is free software; you can redistribute it and/or modify it >> + * under the terms and conditions of the GNU General Public License, >> + * version 2, as published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope it will be useful, but WITHOUT >> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or >> + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for >> + * more details. >> + * >> + * This file implements parsing of Processor Properties Topology Table (PPTT) >> + * which is optionally used to describe the processor and cache topology. >> + * Due to the relative pointers used throughout the table, this doesn't >> + * leverage the existing subtable parsing in the kernel. >> + * >> + * The PPTT structure is an inverted tree, with each node potentially >> + * holding one or two inverted tree data structures describing >> + * the caches available at that level. Each cache structure optionally >> + * contains properties describing the cache at a given level which can be >> + * used to override hardware probed values. >> + */ >> +#define pr_fmt(fmt) "ACPI PPTT: " fmt >> + >> +#include >> +#include >> +#include >> + >> +/* total number of attributes checked by the properties code */ >> +#define PPTT_CHECKED_ATTRIBUTES 6 >> + >> +/* >> + * Given the PPTT table, find and verify that the subtable entry >> + * is located within the table >> + */ >> +static struct acpi_subtable_header *fetch_pptt_subtable( >> + struct acpi_table_header *table_hdr, u32 pptt_ref) >> +{ >> + struct acpi_subtable_header *entry; >> + >> + /* there isn't a subtable at reference 0 */ >> + if (pptt_ref < sizeof(struct acpi_subtable_header)) >> + return NULL; >> + >> + if (pptt_ref + sizeof(struct acpi_subtable_header) > table_hdr->length) >> + return NULL; >> + >> + entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr, pptt_ref); >> + >> + if (pptt_ref + entry->length > table_hdr->length) >> + return NULL; >> + >> + return entry; >> +} >> + >> +static struct acpi_pptt_processor *fetch_pptt_node( >> + struct acpi_table_header *table_hdr, u32 pptt_ref) >> +{ >> + return (struct acpi_pptt_processor *)fetch_pptt_subtable(table_hdr, >> + pptt_ref); >> +} >> + >> +static struct acpi_pptt_cache *fetch_pptt_cache( >> + struct acpi_table_header *table_hdr, u32 pptt_ref) >> +{ >> + return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, >> + pptt_ref); >> +} >> + >> +static struct acpi_subtable_header *acpi_get_pptt_resource( >> + struct acpi_table_header *table_hdr, >> + struct acpi_pptt_processor *node, int resource) >> +{ >> + u32 *ref; >> + >> + if (resource >= node->number_of_priv_resources) >> + return NULL; >> + >> + ref = ACPI_ADD_PTR(u32, node, sizeof(struct acpi_pptt_processor)); >> + ref += resource; >> + >> + return fetch_pptt_subtable(table_hdr, *ref); >> +} >> + >> +/* >> + * Attempt to find a given cache level, while counting the max number >> + * of cache levels for the cache node. >> + * >> + * Given a pptt resource, verify that it is a cache node, then walk >> + * down each level of caches, counting how many levels are found >> + * as well as checking the cache type (icache, dcache, unified). If a >> + * level & type match, then we set found, and continue the search. >> + * Once the entire cache branch has been walked return its max >> + * depth. >> + */ >> +static int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr, >> + int local_level, >> + struct acpi_subtable_header *res, >> + struct acpi_pptt_cache **found, >> + int level, int type) >> +{ >> + struct acpi_pptt_cache *cache; >> + >> + if (res->type != ACPI_PPTT_TYPE_CACHE) >> + return 0; >> + >> + cache = (struct acpi_pptt_cache *) res; >> + while (cache) { >> + local_level++; >> + >> + if ((local_level == level) && >> + (cache->flags & ACPI_PPTT_CACHE_TYPE_VALID) && >> + ((cache->attributes & ACPI_PPTT_MASK_CACHE_TYPE) == type)) { >> + if ((*found != NULL) && (cache != *found)) > > I forgot to mention this earlier, I see you have used parentheses too > liberally at quite some place in this file like the above 4 line. > Please drop those unnecessary parentheses. Yes, those tend to get leftover when I remove code, I realized not long after posting this that in one of the previous patches I actually added a pair where there wasn't one because I first shuffled something into the if condition, then a few revisions later dropped it, and when I squashed it before posting the result was some pointless churn. I will rescan the whole set for this.