ACPI / PPTT: Add a helper to fill a cpumask from a cache_id

MPAM identifies CPUs by the cache_id in the PPTT cache structure.

The driver needs to know which CPUs are associated with the cache.
The CPUs may not all be online, so cacheinfo does not have the
information.

Add a helper to pull this information out of the PPTT.

CC: Rohit Mathew <Rohit.Mathew@arm.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index da49b56a1ef22f48bee9f6c1554f03bde4de7f27..de5f8c018333d7f82f08e0a80c2b6b0be476599e 100644 (file)
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -998,3 +998,68 @@ int find_acpi_cache_level_from_id(u32 cache_id)
 
        return -ENOENT;
 }
+
+/**
+ * acpi_pptt_get_cpumask_from_cache_id() - Get the cpus associated with the
+ *                                        specified cache
+ * @cache_id: The id field of the cache
+ * @cpus: Where to build the cpumask
+ *
+ * Determine which CPUs are below this cache in the PPTT. This allows the property
+ * to be found even if the CPUs are offline.
+ *
+ * The PPTT table must be rev 3 or later,
+ *
+ * Return: -ENOENT if the PPTT doesn't exist, or the cache cannot be found.
+ * Otherwise returns 0 and sets the cpus in the provided cpumask.
+ */
+int acpi_pptt_get_cpumask_from_cache_id(u32 cache_id, cpumask_t *cpus)
+{
+       int cpu;
+       struct acpi_table_header *table;
+
+       cpumask_clear(cpus);
+
+       table = acpi_get_pptt();
+       if (!table)
+               return -ENOENT;
+
+       if (table->revision < 3)
+               return -ENOENT;
+
+       for_each_possible_cpu(cpu) {
+               bool empty;
+               int level = 1;
+               u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
+               struct acpi_pptt_cache *cache;
+               struct acpi_pptt_processor *cpu_node;
+
+               cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
+               if (!cpu_node)
+                       continue;
+
+               do {
+                       int cache_type[] = {CACHE_TYPE_INST, CACHE_TYPE_DATA, CACHE_TYPE_UNIFIED};
+
+                       empty = true;
+                       for (int i = 0; i < ARRAY_SIZE(cache_type); i++) {
+                               struct acpi_pptt_cache_v1_full *cache_v1;
+
+                               cache = acpi_find_cache_node(table, acpi_cpu_id, cache_type[i],
+                                                            level, &cpu_node);
+
+                               if (!cache)
+                                       continue;
+
+                               empty = false;
+
+                               cache_v1 = upgrade_pptt_cache(cache);
+                               if (cache_v1 && cache_v1->cache_id == cache_id)
+                                       cpumask_set_cpu(cpu, cpus);
+                       }
+                       level++;
+               } while (!empty);
+       }
+
+       return 0;
+}

diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index be074bdfd4d17bcab55d64ef909228575660a8c5..a9dbacabdf8912c90e6cb1fe9b2b3d05be6ac0ab 100644 (file)
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1543,6 +1543,7 @@ int find_acpi_cpu_topology_package(unsigned int cpu);
 int find_acpi_cpu_topology_hetero_id(unsigned int cpu);
 void acpi_pptt_get_cpus_from_container(u32 acpi_cpu_id, cpumask_t *cpus);
 int find_acpi_cache_level_from_id(u32 cache_id);
+int acpi_pptt_get_cpumask_from_cache_id(u32 cache_id, cpumask_t *cpus);
 #else
 static inline int acpi_pptt_cpu_is_thread(unsigned int cpu)
 {
@@ -1570,6 +1571,11 @@ static inline int find_acpi_cache_level_from_id(u32 cache_id)
 {
        return -ENOENT;
 }
+static inline int acpi_pptt_get_cpumask_from_cache_id(u32 cache_id,
+                                                     cpumask_t *cpus)
+{
+       return -ENOENT;
+}
 #endif
 
 void acpi_arch_init(void);