ACPI / PPTT: use ACPI ID whenever ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set

Currently, we use the ACPI processor ID only for the leaf/processor nodes
as the specification states it must match the value of the ACPI processor
ID field in the processor’s entry in the MADT.

However, if a PPTT structure represents a processors group, it
matches a processor container UID in the namespace and the
ACPI_PPTT_ACPI_PROCESSOR_ID_VALID flag indicates whether the
ACPI processor ID is valid.

Let's use UID whenever ACPI_PPTT_ACPI_PROCESSOR_ID_VALID is set to be
consistent instead of using table offset as it's currently done for
non-leaf nodes.

Fixes: 2bd00bcd73e5 (ACPI/PPTT: Add Processor Properties Topology Table parsing)
BugLink: http://launchpad.net/bugs/1797200
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Jeremy Linton <jeremy.linton@arm.com>
[ rjw: Changelog (minor) ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
(cherry picked from commit 30998033f62a9915e0f884d680569a39bc9ce133)
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index e5ea1974d1e3820db7e97f8437a7931de70784f8..d1e26cb599bfca340e076500b9e27ec2f3c0bc73 100644 (file)
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -481,8 +481,14 @@ static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
        if (cpu_node) {
                cpu_node = acpi_find_processor_package_id(table, cpu_node,
                                                          level, flag);
-               /* Only the first level has a guaranteed id */
-               if (level == 0)
+               /*
+                * 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);
        }