// 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 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)
pr_warn("Found duplicate cache level/type unable to determine uniqueness\n");
pr_debug("Found cache @ level %d\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,
int *starting_level, int level,
int type)
{
struct acpi_subtable_header *res;
int number_of_levels = *starting_level;
int resource = 0;
struct acpi_pptt_cache *ret = NULL;
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)
{
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 %d 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
*
* 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)
{
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;
}
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);
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;
}
/**
* 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;
}
/**
* 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_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);
}
