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Diffstat (limited to 'drivers/acpi/pptt.c')
| -rw-r--r-- | drivers/acpi/pptt.c | 814 |
1 files changed, 814 insertions, 0 deletions
diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c new file mode 100644 index 0000000000..a35dd0e41c --- /dev/null +++ b/drivers/acpi/pptt.c @@ -0,0 +1,814 @@ +// 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 + * @split_levels: Number of split cache levels (data/instruction). + * @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, + unsigned int *split_levels, + 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 (!(cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)) { + cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache); + continue; + } + + if (split_levels && + (acpi_pptt_match_type(cache->attributes, ACPI_PPTT_CACHE_TYPE_DATA) || + acpi_pptt_match_type(cache->attributes, ACPI_PPTT_CACHE_TYPE_INSTR))) + *split_levels = local_level; + + if (local_level == level && + 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 *split_levels, + 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, + split_levels, 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 cache + * levels and split cache levels (data/instruction). + * @table_hdr: Pointer to the head of the PPTT table + * @cpu_node: processor node we wish to count caches for + * @levels: Number of levels if success. + * @split_levels: Number of split cache levels (data/instruction) if + * success. Can by NULL. + * + * 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 and + * split cache levels (data/instruction) that exist at each level on the way + * up. + */ +static void acpi_count_levels(struct acpi_table_header *table_hdr, + struct acpi_pptt_processor *cpu_node, + unsigned int *levels, unsigned int *split_levels) +{ + do { + acpi_find_cache_level(table_hdr, cpu_node, levels, split_levels, 0, 0); + cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent); + } while (cpu_node); +} + +/** + * 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 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, NULL, 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; + static bool is_pptt_checked; + 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 && !is_pptt_checked) { + status = acpi_get_table(ACPI_SIG_PPTT, 0, &pptt); + if (ACPI_FAILURE(status)) + acpi_pptt_warn_missing(); + + is_pptt_checked = true; + } + + 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_get_cache_info() - Determine the number of cache levels and + * split cache levels (data/instruction) and for a PE. + * @cpu: Kernel logical CPU number + * @levels: Number of levels if success. + * @split_levels: Number of levels being split (i.e. data/instruction) + * if success. Can by NULL. + * + * 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: -ENOENT if no PPTT table or no PPTT processor struct found. + * 0 on success. + */ +int acpi_get_cache_info(unsigned int cpu, unsigned int *levels, + unsigned int *split_levels) +{ + struct acpi_pptt_processor *cpu_node; + struct acpi_table_header *table; + u32 acpi_cpu_id; + + *levels = 0; + if (split_levels) + *split_levels = 0; + + table = acpi_get_pptt(); + if (!table) + return -ENOENT; + + pr_debug("Cache Setup: find cache levels for CPU=%d\n", cpu); + + acpi_cpu_id = get_acpi_id_for_cpu(cpu); + cpu_node = acpi_find_processor_node(table, acpi_cpu_id); + if (!cpu_node) + return -ENOENT; + + acpi_count_levels(table, cpu_node, levels, split_levels); + + pr_debug("Cache Setup: last_level=%d split_levels=%d\n", + *levels, split_levels ? *split_levels : -1); + + return 0; +} + +/** + * 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); +} |