linux/drivers/acpi/pptt.c
Sudeep Holla 0c80f9e165 ACPI: PPTT: Leave the table mapped for the runtime usage
Currently, everytime an information needs to be fetched from the PPTT,
the table is mapped via acpi_get_table() and unmapped after the use via
acpi_put_table() which is fine. However we do this at runtime especially
when the CPU is hotplugged out and plugged in back since we re-populate
the cache topology and other information.

However, with the support to fetch LLC information from the PPTT in the
cpuhotplug path which is executed in the atomic context, it is preferred
to avoid mapping and unmapping of the PPTT for every single use as the
acpi_get_table() might sleep waiting for a mutex.

In order to avoid the same, the table is needs to just mapped once on
the boot CPU and is never unmapped allowing it to be used at runtime
with out the hassle of mapping and unmapping the table.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

--

Hi Rafael,

Sorry to bother you again on this PPTT changes. Guenter reported an issue
with lockdep enabled in -next that include my cacheinfo/arch_topology changes
to utilise LLC from PPTT in the CPU hotplug path.

Please ack the change once you are happy so that I can get it merged with
other fixes via Greg's tree.

Regards,
Sudeep

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220720-arch_topo_fixes-v3-2-43d696288e84@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-07-22 10:04:43 +02:00

797 lines
24 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* pptt.c - parsing of Processor Properties Topology Table (PPTT)
*
* Copyright (C) 2018, ARM
*
* This file implements parsing of the Processor Properties Topology Table
* 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>
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 (entry->length == 0)
return NULL;
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);
}
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);
}
/**
* acpi_pptt_walk_cache() - Attempt to find the requested acpi_pptt_cache
* @table_hdr: Pointer to the head of the PPTT table
* @local_level: passed res reflects this cache level
* @res: cache resource in the PPTT we want to walk
* @found: returns a pointer to the requested level if found
* @level: the requested cache level
* @type: the requested cache 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.
*
* Return: The cache structure and the level we terminated with.
*/
static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
unsigned int local_level,
struct acpi_subtable_header *res,
struct acpi_pptt_cache **found,
unsigned 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)
pr_warn("Found duplicate cache level/type unable to determine uniqueness\n");
pr_debug("Found cache @ level %u\n", level);
*found = cache;
/*
* continue looking at this node's resource list
* to verify that we don't find a duplicate
* cache node.
*/
}
cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache);
}
return local_level;
}
static struct acpi_pptt_cache *
acpi_find_cache_level(struct acpi_table_header *table_hdr,
struct acpi_pptt_processor *cpu_node,
unsigned int *starting_level, unsigned int level,
int type)
{
struct acpi_subtable_header *res;
unsigned int number_of_levels = *starting_level;
int resource = 0;
struct acpi_pptt_cache *ret = NULL;
unsigned int local_level;
/* walk down from processor node */
while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
resource++;
local_level = acpi_pptt_walk_cache(table_hdr, *starting_level,
res, &ret, level, type);
/*
* we are looking for the max depth. Since its potentially
* possible for a given node to have resources with differing
* depths verify that the depth we have found is the largest.
*/
if (number_of_levels < local_level)
number_of_levels = local_level;
}
if (number_of_levels > *starting_level)
*starting_level = number_of_levels;
return ret;
}
/**
* acpi_count_levels() - Given a PPTT table, and a CPU node, count the caches
* @table_hdr: Pointer to the head of the PPTT table
* @cpu_node: processor node we wish to count caches for
*
* Given a processor node containing a processing unit, walk into it and count
* how many levels exist solely for it, and then walk up each level until we hit
* the root node (ignore the package level because it may be possible to have
* caches that exist across packages). Count the number of cache levels that
* exist at each level on the way up.
*
* Return: Total number of levels found.
*/
static int acpi_count_levels(struct acpi_table_header *table_hdr,
struct acpi_pptt_processor *cpu_node)
{
int total_levels = 0;
do {
acpi_find_cache_level(table_hdr, cpu_node, &total_levels, 0, 0);
cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
} while (cpu_node);
return total_levels;
}
/**
* acpi_pptt_leaf_node() - Given a processor node, determine if its a leaf
* @table_hdr: Pointer to the head of the PPTT table
* @node: passed node is checked to see if its a leaf
*
* Determine if the *node parameter is a leaf node by iterating the
* PPTT table, looking for nodes which reference it.
*
* Return: 0 if we find a node referencing the passed node (or table error),
* or 1 if we don't.
*/
static int acpi_pptt_leaf_node(struct acpi_table_header *table_hdr,
struct acpi_pptt_processor *node)
{
struct acpi_subtable_header *entry;
unsigned long table_end;
u32 node_entry;
struct acpi_pptt_processor *cpu_node;
u32 proc_sz;
if (table_hdr->revision > 1)
return (node->flags & ACPI_PPTT_ACPI_LEAF_NODE);
table_end = (unsigned long)table_hdr + table_hdr->length;
node_entry = ACPI_PTR_DIFF(node, table_hdr);
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) {
cpu_node = (struct acpi_pptt_processor *)entry;
if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
cpu_node->parent == node_entry)
return 0;
if (entry->length == 0)
return 0;
entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
entry->length);
}
return 1;
}
/**
* acpi_find_processor_node() - Given a PPTT table find the requested processor
* @table_hdr: Pointer to the head of the PPTT table
* @acpi_cpu_id: CPU we are searching for
*
* Find the subtable entry describing the provided processor.
* This is done by iterating the PPTT table looking for processor nodes
* which have an acpi_processor_id that matches the acpi_cpu_id parameter
* passed into the function. If we find a node that matches this criteria
* we verify that its a leaf node in the topology rather than depending
* on the valid flag, which doesn't need to be set for leaf nodes.
*
* Return: NULL, or the processors acpi_pptt_processor*
*/
static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_header *table_hdr,
u32 acpi_cpu_id)
{
struct acpi_subtable_header *entry;
unsigned long table_end;
struct acpi_pptt_processor *cpu_node;
u32 proc_sz;
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 *);
/* find the processor structure associated with this cpuid */
while ((unsigned long)entry + proc_sz < table_end) {
cpu_node = (struct acpi_pptt_processor *)entry;
if (entry->length == 0) {
pr_warn("Invalid zero length subtable\n");
break;
}
if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
acpi_cpu_id == cpu_node->acpi_processor_id &&
acpi_pptt_leaf_node(table_hdr, cpu_node)) {
return (struct acpi_pptt_processor *)entry;
}
entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
entry->length);
}
return NULL;
}
static int acpi_find_cache_levels(struct acpi_table_header *table_hdr,
u32 acpi_cpu_id)
{
int number_of_levels = 0;
struct acpi_pptt_processor *cpu;
cpu = acpi_find_processor_node(table_hdr, acpi_cpu_id);
if (cpu)
number_of_levels = acpi_count_levels(table_hdr, cpu);
return number_of_levels;
}
static u8 acpi_cache_type(enum cache_type type)
{
switch (type) {
case CACHE_TYPE_DATA:
pr_debug("Looking for data cache\n");
return ACPI_PPTT_CACHE_TYPE_DATA;
case CACHE_TYPE_INST:
pr_debug("Looking for instruction cache\n");
return ACPI_PPTT_CACHE_TYPE_INSTR;
default:
case CACHE_TYPE_UNIFIED:
pr_debug("Looking for unified cache\n");
/*
* It is important that ACPI_PPTT_CACHE_TYPE_UNIFIED
* contains the bit pattern that will match both
* ACPI unified bit patterns because we use it later
* to match both cases.
*/
return ACPI_PPTT_CACHE_TYPE_UNIFIED;
}
}
static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *table_hdr,
u32 acpi_cpu_id,
enum cache_type type,
unsigned int level,
struct acpi_pptt_processor **node)
{
unsigned int total_levels = 0;
struct acpi_pptt_cache *found = NULL;
struct acpi_pptt_processor *cpu_node;
u8 acpi_type = acpi_cache_type(type);
pr_debug("Looking for CPU %d's level %u cache type %d\n",
acpi_cpu_id, level, acpi_type);
cpu_node = acpi_find_processor_node(table_hdr, acpi_cpu_id);
while (cpu_node && !found) {
found = acpi_find_cache_level(table_hdr, cpu_node,
&total_levels, level, acpi_type);
*node = cpu_node;
cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
}
return found;
}
/**
* update_cache_properties() - Update cacheinfo for the given processor
* @this_leaf: Kernel cache info structure being updated
* @found_cache: The PPTT node describing this cache instance
* @cpu_node: A unique reference to describe this cache instance
* @revision: The revision of the PPTT table
*
* The ACPI spec implies that the fields in the cache structures are used to
* extend and correct the information probed from the hardware. Lets only
* set fields that we determine are VALID.
*
* Return: nothing. Side effect of updating the global cacheinfo
*/
static void update_cache_properties(struct cacheinfo *this_leaf,
struct acpi_pptt_cache *found_cache,
struct acpi_pptt_processor *cpu_node,
u8 revision)
{
struct acpi_pptt_cache_v1* found_cache_v1;
this_leaf->fw_token = cpu_node;
if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
this_leaf->size = found_cache->size;
if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
this_leaf->coherency_line_size = found_cache->line_size;
if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
this_leaf->number_of_sets = found_cache->number_of_sets;
if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
this_leaf->ways_of_associativity = found_cache->associativity;
if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
case ACPI_PPTT_CACHE_POLICY_WT:
this_leaf->attributes = CACHE_WRITE_THROUGH;
break;
case ACPI_PPTT_CACHE_POLICY_WB:
this_leaf->attributes = CACHE_WRITE_BACK;
break;
}
}
if (found_cache->flags & ACPI_PPTT_ALLOCATION_TYPE_VALID) {
switch (found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE) {
case ACPI_PPTT_CACHE_READ_ALLOCATE:
this_leaf->attributes |= CACHE_READ_ALLOCATE;
break;
case ACPI_PPTT_CACHE_WRITE_ALLOCATE:
this_leaf->attributes |= CACHE_WRITE_ALLOCATE;
break;
case ACPI_PPTT_CACHE_RW_ALLOCATE:
case ACPI_PPTT_CACHE_RW_ALLOCATE_ALT:
this_leaf->attributes |=
CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE;
break;
}
}
/*
* If cache type is NOCACHE, then the cache hasn't been specified
* via other mechanisms. Update the type if a cache type has been
* provided.
*
* Note, we assume such caches are unified based on conventional system
* design and known examples. Significant work is required elsewhere to
* fully support data/instruction only type caches which are only
* specified in PPTT.
*/
if (this_leaf->type == CACHE_TYPE_NOCACHE &&
found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
this_leaf->type = CACHE_TYPE_UNIFIED;
if (revision >= 3 && (found_cache->flags & ACPI_PPTT_CACHE_ID_VALID)) {
found_cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
found_cache, sizeof(struct acpi_pptt_cache));
this_leaf->id = found_cache_v1->cache_id;
this_leaf->attributes |= CACHE_ID;
}
}
static void cache_setup_acpi_cpu(struct acpi_table_header *table,
unsigned int cpu)
{
struct acpi_pptt_cache *found_cache;
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
struct cacheinfo *this_leaf;
unsigned int index = 0;
struct acpi_pptt_processor *cpu_node = NULL;
while (index < get_cpu_cacheinfo(cpu)->num_leaves) {
this_leaf = this_cpu_ci->info_list + index;
found_cache = acpi_find_cache_node(table, acpi_cpu_id,
this_leaf->type,
this_leaf->level,
&cpu_node);
pr_debug("found = %p %p\n", found_cache, cpu_node);
if (found_cache)
update_cache_properties(this_leaf, found_cache,
ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)),
table->revision);
index++;
}
}
static bool flag_identical(struct acpi_table_header *table_hdr,
struct acpi_pptt_processor *cpu)
{
struct acpi_pptt_processor *next;
/* heterogeneous machines must use PPTT revision > 1 */
if (table_hdr->revision < 2)
return false;
/* Locate the last node in the tree with IDENTICAL set */
if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) {
next = fetch_pptt_node(table_hdr, cpu->parent);
if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL))
return true;
}
return false;
}
/* Passing level values greater than this will result in search termination */
#define PPTT_ABORT_PACKAGE 0xFF
static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr,
struct acpi_pptt_processor *cpu,
int level, int flag)
{
struct acpi_pptt_processor *prev_node;
while (cpu && level) {
/* special case the identical flag to find last identical */
if (flag == ACPI_PPTT_ACPI_IDENTICAL) {
if (flag_identical(table_hdr, cpu))
break;
} else if (cpu->flags & flag)
break;
pr_debug("level %d\n", level);
prev_node = fetch_pptt_node(table_hdr, cpu->parent);
if (prev_node == NULL)
break;
cpu = prev_node;
level--;
}
return cpu;
}
static void acpi_pptt_warn_missing(void)
{
pr_warn_once("No PPTT table found, CPU and cache topology may be inaccurate\n");
}
/**
* topology_get_acpi_cpu_tag() - Find a unique topology value for a feature
* @table: Pointer to the head of the PPTT table
* @cpu: Kernel logical CPU number
* @level: A level that terminates the search
* @flag: A flag which terminates the search
*
* Get a unique value given a CPU, and a topology level, that can be
* matched to determine which cpus share common topological features
* at that level.
*
* Return: Unique value, or -ENOENT if unable to locate CPU
*/
static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
unsigned int cpu, int level, int flag)
{
struct acpi_pptt_processor *cpu_node;
u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
if (cpu_node) {
cpu_node = acpi_find_processor_tag(table, cpu_node,
level, flag);
/*
* As per specification if the processor structure represents
* an actual processor, then ACPI processor ID must be valid.
* For processor containers ACPI_PPTT_ACPI_PROCESSOR_ID_VALID
* should be set if the UID is valid
*/
if (level == 0 ||
cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
return cpu_node->acpi_processor_id;
return ACPI_PTR_DIFF(cpu_node, table);
}
pr_warn_once("PPTT table found, but unable to locate core %d (%d)\n",
cpu, acpi_cpu_id);
return -ENOENT;
}
static struct acpi_table_header *acpi_get_pptt(void)
{
static struct acpi_table_header *pptt;
acpi_status status;
/*
* PPTT will be used at runtime on every CPU hotplug in path, so we
* don't need to call acpi_put_table() to release the table mapping.
*/
if (!pptt) {
status = acpi_get_table(ACPI_SIG_PPTT, 0, &pptt);
if (ACPI_FAILURE(status))
acpi_pptt_warn_missing();
}
return pptt;
}
static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
{
struct acpi_table_header *table;
int retval;
table = acpi_get_pptt();
if (!table)
return -ENOENT;
retval = topology_get_acpi_cpu_tag(table, cpu, level, flag);
pr_debug("Topology Setup ACPI CPU %d, level %d ret = %d\n",
cpu, level, retval);
return retval;
}
/**
* check_acpi_cpu_flag() - Determine if CPU node has a flag set
* @cpu: Kernel logical CPU number
* @rev: The minimum PPTT revision defining the flag
* @flag: The flag itself
*
* Check the node representing a CPU for a given flag.
*
* Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
* the table revision isn't new enough.
* 1, any passed flag set
* 0, flag unset
*/
static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
{
struct acpi_table_header *table;
u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
struct acpi_pptt_processor *cpu_node = NULL;
int ret = -ENOENT;
table = acpi_get_pptt();
if (!table)
return -ENOENT;
if (table->revision >= rev)
cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
if (cpu_node)
ret = (cpu_node->flags & flag) != 0;
return ret;
}
/**
* acpi_find_last_cache_level() - Determines the number of cache levels for a PE
* @cpu: Kernel logical CPU number
*
* Given a logical CPU number, returns the number of levels of cache represented
* in the PPTT. Errors caused by lack of a PPTT table, or otherwise, return 0
* indicating we didn't find any cache levels.
*
* Return: Cache levels visible to this core.
*/
int acpi_find_last_cache_level(unsigned int cpu)
{
u32 acpi_cpu_id;
struct acpi_table_header *table;
int number_of_levels = 0;
table = acpi_get_pptt();
if (!table)
return -ENOENT;
pr_debug("Cache Setup find last level CPU=%d\n", cpu);
acpi_cpu_id = get_acpi_id_for_cpu(cpu);
number_of_levels = acpi_find_cache_levels(table, acpi_cpu_id);
pr_debug("Cache Setup find last level level=%d\n", number_of_levels);
return number_of_levels;
}
/**
* cache_setup_acpi() - Override CPU cache topology with data from the PPTT
* @cpu: Kernel logical CPU number
*
* Updates the global cache info provided by cpu_get_cacheinfo()
* when there are valid properties in the acpi_pptt_cache nodes. A
* successful parse may not result in any updates if none of the
* cache levels have any valid flags set. Further, a unique value is
* associated with each known CPU cache entry. This unique value
* can be used to determine whether caches are shared between CPUs.
*
* Return: -ENOENT on failure to find table, or 0 on success
*/
int cache_setup_acpi(unsigned int cpu)
{
struct acpi_table_header *table;
table = acpi_get_pptt();
if (!table)
return -ENOENT;
pr_debug("Cache Setup ACPI CPU %d\n", cpu);
cache_setup_acpi_cpu(table, cpu);
return 0;
}
/**
* acpi_pptt_cpu_is_thread() - Determine if CPU is a thread
* @cpu: Kernel logical CPU number
*
* Return: 1, a thread
* 0, not a thread
* -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or
* the table revision isn't new enough.
*/
int acpi_pptt_cpu_is_thread(unsigned int cpu)
{
return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);
}
/**
* find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
* @cpu: Kernel logical CPU number
* @level: The topological level for which we would like a unique ID
*
* Determine a topology unique ID for each thread/core/cluster/mc_grouping
* /socket/etc. This ID can then be used to group peers, which will have
* matching ids.
*
* The search terminates when either the requested level is found or
* we reach a root node. Levels beyond the termination point will return the
* same unique ID. The unique id for level 0 is the acpi processor id. All
* other levels beyond this use a generated value to uniquely identify
* a topological feature.
*
* Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
* Otherwise returns a value which represents a unique topological feature.
*/
int find_acpi_cpu_topology(unsigned int cpu, int level)
{
return find_acpi_cpu_topology_tag(cpu, level, 0);
}
/**
* find_acpi_cpu_topology_package() - Determine a unique CPU package value
* @cpu: Kernel logical CPU number
*
* Determine a topology unique package ID for the given CPU.
* This ID can then be used to group peers, which will have matching ids.
*
* The search terminates when either a level is found with the PHYSICAL_PACKAGE
* flag set or we reach a root node.
*
* Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
* Otherwise returns a value which represents the package for this CPU.
*/
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_cluster() - Determine a unique CPU cluster value
* @cpu: Kernel logical CPU number
*
* Determine a topology unique cluster ID for the given CPU/thread.
* This ID can then be used to group peers, which will have matching ids.
*
* The cluster, if present is the level of topology above CPUs. In a
* multi-thread CPU, it will be the level above the CPU, not the thread.
* It may not exist in single CPU systems. In simple multi-CPU systems,
* it may be equal to the package topology level.
*
* Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found
* or there is no toplogy level above the CPU..
* Otherwise returns a value which represents the package for this CPU.
*/
int find_acpi_cpu_topology_cluster(unsigned int cpu)
{
struct acpi_table_header *table;
struct acpi_pptt_processor *cpu_node, *cluster_node;
u32 acpi_cpu_id;
int retval;
int is_thread;
table = acpi_get_pptt();
if (!table)
return -ENOENT;
acpi_cpu_id = get_acpi_id_for_cpu(cpu);
cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
if (!cpu_node || !cpu_node->parent)
return -ENOENT;
is_thread = cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD;
cluster_node = fetch_pptt_node(table, cpu_node->parent);
if (!cluster_node)
return -ENOENT;
if (is_thread) {
if (!cluster_node->parent)
return -ENOENT;
cluster_node = fetch_pptt_node(table, cluster_node->parent);
if (!cluster_node)
return -ENOENT;
}
if (cluster_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
retval = cluster_node->acpi_processor_id;
else
retval = ACPI_PTR_DIFF(cluster_node, table);
return retval;
}
/**
* 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);
}