thermal: intel: hfi: Give HFI instances package scope

The Intel Software Developer's Manual defines the scope of HFI (registers
and memory buffer) as a package. Use package scope(*) in the software
representation of an HFI instance.

Using die scope in HFI instances has the effect of creating multiple
conflicting instances for the same package: each instance allocates its
own memory buffer and configures the same package-level registers.
Specifically, only one of the allocated memory buffers can be set in the
MSR_IA32_HW_FEEDBACK_PTR register. CPUs get incorrect HFI data from the
table.

The problem does not affect current HFI-capable platforms because they
all have single-die processors.

(*) We used die scope for HFI instances because there had been
    processors with packages enumerated as dies. None of those systems
    supported HFI, though. If such a system emerged, it would need to
    be quirked.

Co-developed-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Link: https://patch.msgid.link/20240703055445.125362-1-rui.zhang@intel.com
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/thermal/intel/intel_hfi.c b/drivers/thermal/intel/intel_hfi.c
index a180a98bb9f154201775eaee162ca2524421bde8..5b18a46a10b06df0eb776247d706bcc1d82071ef 100644 (file)
--- a/drivers/thermal/intel/intel_hfi.c
+++ b/drivers/thermal/intel/intel_hfi.c
@@ -401,10 +401,10 @@ static void hfi_disable(void)
  * intel_hfi_online() - Enable HFI on @cpu
  * @cpu:       CPU in which the HFI will be enabled
  *
- * Enable the HFI to be used in @cpu. The HFI is enabled at the die/package
- * level. The first CPU in the die/package to come online does the full HFI
+ * Enable the HFI to be used in @cpu. The HFI is enabled at the package
+ * level. The first CPU in the package to come online does the full HFI
  * initialization. Subsequent CPUs will just link themselves to the HFI
- * instance of their die/package.
+ * instance of their package.
  *
  * This function is called before enabling the thermal vector in the local APIC
  * in order to ensure that @cpu has an associated HFI instance when it receives
@@ -414,31 +414,31 @@ void intel_hfi_online(unsigned int cpu)
 {
        struct hfi_instance *hfi_instance;
        struct hfi_cpu_info *info;
-       u16 die_id;
+       u16 pkg_id;
 
        /* Nothing to do if hfi_instances are missing. */
        if (!hfi_instances)
                return;
 
        /*
-        * Link @cpu to the HFI instance of its package/die. It does not
+        * Link @cpu to the HFI instance of its package. It does not
         * matter whether the instance has been initialized.
         */
        info = &per_cpu(hfi_cpu_info, cpu);
-       die_id = topology_logical_die_id(cpu);
+       pkg_id = topology_logical_package_id(cpu);
        hfi_instance = info->hfi_instance;
        if (!hfi_instance) {
-               if (die_id >= max_hfi_instances)
+               if (pkg_id >= max_hfi_instances)
                        return;
 
-               hfi_instance = &hfi_instances[die_id];
+               hfi_instance = &hfi_instances[pkg_id];
                info->hfi_instance = hfi_instance;
        }
 
        init_hfi_cpu_index(info);
 
        /*
-        * Now check if the HFI instance of the package/die of @cpu has been
+        * Now check if the HFI instance of the package of @cpu has been
         * initialized (by checking its header). In such case, all we have to
         * do is to add @cpu to this instance's cpumask and enable the instance
         * if needed.
@@ -504,7 +504,7 @@ free_hw_table:
  *
  * On some processors, hardware remembers previous programming settings even
  * after being reprogrammed. Thus, keep HFI enabled even if all CPUs in the
- * die/package of @cpu are offline. See note in intel_hfi_online().
+ * package of @cpu are offline. See note in intel_hfi_online().
  */
 void intel_hfi_offline(unsigned int cpu)
 {
@@ -674,9 +674,13 @@ void __init intel_hfi_init(void)
        if (hfi_parse_features())
                return;
 
-       /* There is one HFI instance per die/package. */
-       max_hfi_instances = topology_max_packages() *
-                           topology_max_dies_per_package();
+       /*
+        * Note: HFI resources are managed at the physical package scope.
+        * There could be platforms that enumerate packages as Linux dies.
+        * Special handling would be needed if this happens on an HFI-capable
+        * platform.
+        */
+       max_hfi_instances = topology_max_packages();
 
        /*
         * This allocation may fail. CPU hotplug callbacks must check