Messages in this thread | | | Subject | Re: [PATCH v7 05/13] ACPI/PPTT: Add Processor Properties Topology Table parsing | From | Jeremy Linton <> | Date | Tue, 20 Mar 2018 08:25:42 -0500 |
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Hi,
Thanks for taking a look at this.
On 03/19/2018 05:46 AM, Rafael J. Wysocki wrote: > On Wednesday, February 28, 2018 11:06:11 PM CET 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 <jeremy.linton@arm.com> > > A couple of cosmetic comments. > >> --- >> drivers/acpi/pptt.c | 488 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 488 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..883e4318c6cd >> --- /dev/null >> +++ b/drivers/acpi/pptt.c >> @@ -0,0 +1,488 @@ > > Use an SPDX license ID here and then you don't need the license boilerplate > below.
Sure, good point!
> >> +/* >> + * 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 <linux/acpi.h> >> +#include <linux/cacheinfo.h> >> +#include <acpi/processor.h> >> + >> +/* >> + * Given the PPTT table, find and verify that the subtable entry >> + * is located within the table >> + */ > > If you add a comment above a function, make it a kerneldoc. That > never hurts, but really helps sometimes.
Sure, I did that for the visible symbols. I will convert the internal ones as well.
> >> +static struct acpi_subtable_header *fetch_pptt_subtable( > > Don't break the line here, it can be broken after the first arg. > > That's OK even if it is more than 80 chars long. > >> + 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); > > You don't need to break this line too.
Sure.
> >> +} >> + >> +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); > > And here. > >> +} >> + >> +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); >> +} >> + >> +/* >> + * Match the type passed and special case the TYPE_UNIFIED so that >> + * it match both ACPI_PPTT_CACHE_TYPE_UNIFIED(_ALT) types. >> + */ >> +static inline bool acpi_pptt_match_type(int table_type, int type) >> +{ >> + return (((table_type & ACPI_PPTT_MASK_CACHE_TYPE) == type) || >> + (table_type & ACPI_PPTT_CACHE_TYPE_UNIFIED & type)); >> +} >> + >> +/* >> + * 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) && >> + acpi_pptt_match_type(cache->attributes, type)) { >> + if ((*found != NULL) && (cache != *found)) > > Inner parens are not necessary (and above and in some other places too). Sure.
> >> + pr_err("Found duplicate cache level/type unable to determine uniqueness\n"); > > This is not an error, rather a statement that something is inconsistent in the > ACPI table, so please consider using a different log level here.
pr_warn seems to be the other common choice in the acpi directory for table errors, I will will use that.
> > [cut] > > I guess I could post similar comments for the other general ACPI patches in > this series, so please address them in there too if applicable. >
Ok, I will look over them again.
Thanks,
> Thanks! >
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