1 files changed, 30 insertions, 0 deletions

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 51cc29909e08..b1ec78b8a645 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -83,6 +83,31 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
         return 0;
 }
 
+/*
+ * Retrieve the ARM CPU physical identifier (MPIDR)
+ */
+static int map_gicc_mpidr(struct acpi_subtable_header *entry,
+                int device_declaration, u32 acpi_id, phys_cpuid_t *mpidr)
+{
+        struct acpi_madt_generic_interrupt *gicc =
+            container_of(entry, struct acpi_madt_generic_interrupt, header);
+
+        if (!(gicc->flags & ACPI_MADT_ENABLED))
+                return -ENODEV;
+
+        /* device_declaration means Device object in DSDT, in the
+         * GIC interrupt model, logical processors are required to
+         * have a Processor Device object in the DSDT, so we should
+         * check device_declaration here
+         */
+        if (device_declaration && (gicc->uid == acpi_id)) {
+                *mpidr = gicc->arm_mpidr;
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
 static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
 {
         unsigned long madt_end, entry;
@@ -111,6 +136,9 @@ static phys_cpuid_t map_madt_entry(int type, u32 acpi_id)
                 } else if (header->type == ACPI_MADT_TYPE_LOCAL_SAPIC) {
                         if (!map_lsapic_id(header, type, acpi_id, &phys_id))
                                 break;
+                } else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT) {
+                        if (!map_gicc_mpidr(header, type, acpi_id, &phys_id))
+                                break;
                 }
                 entry += header->length;
         }
@@ -143,6 +171,8 @@ static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id)
                 map_lsapic_id(header, type, acpi_id, &phys_id);
         else if (header->type == ACPI_MADT_TYPE_LOCAL_X2APIC)
                 map_x2apic_id(header, type, acpi_id, &phys_id);
+        else if (header->type == ACPI_MADT_TYPE_GENERIC_INTERRUPT)
+                map_gicc_mpidr(header, type, acpi_id, &phys_id);
 
 exit:
         kfree(buffer.pointer);