// 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, cpu_node, 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 int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag) { struct acpi_table_header *table; acpi_status status; int retval; status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); if (ACPI_FAILURE(status)) { acpi_pptt_warn_missing(); 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); acpi_put_table(table); 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; acpi_status status; u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu); struct acpi_pptt_processor *cpu_node = NULL; int ret = -ENOENT; status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); if (ACPI_FAILURE(status)) { acpi_pptt_warn_missing(); return ret; } if (table->revision >= rev) cpu_node = acpi_find_processor_node(table, acpi_cpu_id); if (cpu_node) ret = (cpu_node->flags & flag) != 0; acpi_put_table(table); 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; acpi_status status; pr_debug("Cache Setup find last level CPU=%d\n", cpu); acpi_cpu_id = get_acpi_id_for_cpu(cpu); status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); if (ACPI_FAILURE(status)) { acpi_pptt_warn_missing(); } else { number_of_levels = acpi_find_cache_levels(table, acpi_cpu_id); acpi_put_table(table); } 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; acpi_status status; pr_debug("Cache Setup ACPI CPU %d\n", cpu); status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); if (ACPI_FAILURE(status)) { acpi_pptt_warn_missing(); return -ENOENT; } cache_setup_acpi_cpu(table, cpu); acpi_put_table(table); return status; } /** * 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_cache_topology() - Determine a unique cache topology value * @cpu: Kernel logical CPU number * @level: The cache level for which we would like a unique ID * * Determine a unique ID for each unified cache in the system * * 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_cache_topology(unsigned int cpu, int level) { struct acpi_table_header *table; struct acpi_pptt_cache *found_cache; acpi_status status; u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu); struct acpi_pptt_processor *cpu_node = NULL; int ret = -1; status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); if (ACPI_FAILURE(status)) { acpi_pptt_warn_missing(); return -ENOENT; } found_cache = acpi_find_cache_node(table, acpi_cpu_id, CACHE_TYPE_UNIFIED, level, &cpu_node); if (found_cache) ret = ACPI_PTR_DIFF(cpu_node, table); acpi_put_table(table); return ret; } /** * 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; acpi_status status; struct acpi_pptt_processor *cpu_node, *cluster_node; u32 acpi_cpu_id; int retval; int is_thread; status = acpi_get_table(ACPI_SIG_PPTT, 0, &table); if (ACPI_FAILURE(status)) { acpi_pptt_warn_missing(); return -ENOENT; } acpi_cpu_id = get_acpi_id_for_cpu(cpu); cpu_node = acpi_find_processor_node(table, acpi_cpu_id); if (cpu_node == NULL || !cpu_node->parent) { retval = -ENOENT; goto put_table; } is_thread = cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD; cluster_node = fetch_pptt_node(table, cpu_node->parent); if (cluster_node == NULL) { retval = -ENOENT; goto put_table; } if (is_thread) { if (!cluster_node->parent) { retval = -ENOENT; goto put_table; } cluster_node = fetch_pptt_node(table, cluster_node->parent); if (cluster_node == NULL) { retval = -ENOENT; goto put_table; } } if (cluster_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID) retval = cluster_node->acpi_processor_id; else retval = ACPI_PTR_DIFF(cluster_node, table); put_table: acpi_put_table(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); }