1 files changed, 29 insertions, 0 deletions
diff --git a/src/arch/x86/cpu.c b/src/arch/x86/cpu.c
index 80d4d0da4a..f19b389441 100644
--- a/src/arch/x86/cpu.c
+++ b/src/arch/x86/cpu.c
@@ -219,6 +219,35 @@ static void set_cpu_ops(struct device *cpu)
 	cpu->ops = driver ? driver->ops : NULL;
 }
 
+/* Keep track of default apic ids for SMM. */
+static int cpus_default_apic_id[CONFIG_MAX_CPUS];
+
+/*
+ * When CPUID executes with EAX set to 1, additional processor identification
+ * information is returned to EBX register:
+ * Default APIC ID: EBX[31-24] - this number is the 8 bit ID that is assigned
+ * to the local APIC on the processor during power on.
+ */
+static int initial_lapicid(void)
+{
+	return cpuid_ebx(1) >> 24;
+}
+
+/* Function to keep track of cpu default apic_id */
+void cpu_add_map_entry(unsigned int index)
+{
+	cpus_default_apic_id[index] = initial_lapicid();
+}
+
+/* Returns default APIC id based on logical_cpu number or < 0 on failure. */
+int cpu_get_apic_id(int logical_cpu)
+{
+	if (logical_cpu >= CONFIG_MAX_CPUS || logical_cpu < 0)
+		return -1;
+
+	return cpus_default_apic_id[logical_cpu];
+}
+
 void cpu_initialize(unsigned int index)
 {
 	/* Because we busy wait at the printk spinlock.