ACPI / PPTT: Find PPTT processor node by cache id

openeuler inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I77UDW
CVE: NA

--------------------------------

The MPAM table identifies caches by id, but the driver also wants to know
the processor node.

Add a helper that walks every possible cache, until it finds the one
identified by id, then return processor node.
Signed-off-by: NYu Liao <liaoyu15@huawei.com>

drivers/acpi/pptt.c

@@ -958,3 +958,58 @@ int __init acpi_pptt_init(void)
 
 	return 0;
 }
+
+struct acpi_pptt_processor *find_acpi_processor_node_from_cache_id(u32 cache_id)
+{
+	u32 acpi_cpu_id;
+	acpi_status status;
+	int level, cpu, num_levels;
+	struct acpi_pptt_cache *cache;
+	struct acpi_table_header *table;
+	struct acpi_pptt_cache_v1 *cache_v1;
+	struct acpi_pptt_processor *cpu_node;
+
+	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
+	if (ACPI_FAILURE(status)) {
+		acpi_pptt_warn_missing();
+		return NULL;
+	}
+
+	if (table->revision < 3) {
+		acpi_put_table(table);
+		return NULL;
+	}
+
+	/*
+	 * If we found the cache first, we'd still need to walk from each CPU
+	 * to find the level...
+	 */
+	for_each_possible_cpu(cpu) {
+		acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+		cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
+		if (!cpu_node)
+			break;
+		num_levels = acpi_count_levels(table, cpu_node);
+
+		for (level = 0; level <= num_levels; level++) {
+			cache = acpi_find_cache_node(table, acpi_cpu_id,
+						     ACPI_PPTT_CACHE_TYPE_UNIFIED,
+						     level, &cpu_node);
+			if (!cache)
+				continue;
+
+			cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
+						cache,
+						sizeof(struct acpi_pptt_cache));
+
+			if (cache->flags & ACPI_PPTT_CACHE_ID_VALID &&
+			    cache_v1->cache_id == cache_id) {
+				acpi_put_table(table);
+				return cpu_node;
+			}
+		}
+	}
+
+	acpi_put_table(table);
+	return NULL;
+}

include/linux/acpi.h

@@ -1367,6 +1367,7 @@ int find_acpi_cpu_topology_cluster(unsigned int cpu);
 int find_acpi_cpu_topology_package(unsigned int cpu);
 int find_acpi_cpu_topology_hetero_id(unsigned int cpu);
 int find_acpi_cpu_cache_topology(unsigned int cpu, int level);
+struct acpi_pptt_processor *find_acpi_processor_node_from_cache_id(u32 cache_id);
 #else
 static inline int acpi_pptt_cpu_is_thread(unsigned int cpu)
 {
@@ -1392,6 +1393,10 @@ static inline int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
 {
 	return -EINVAL;
 }
+static inline struct acpi_pptt_processor *find_acpi_processor_node_from_cache_id(u32 cache_id)
+{
+	return NULL;
+}
 #endif
 
 #ifdef CONFIG_ACPI