1 files changed, 20 insertions, 2 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b9338b8cf420..68219a919dfd 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1943,10 +1943,28 @@ void disconnect_bsp_APIC(int virt_wire_setup)
 
 void __cpuinit generic_processor_info(int apicid, int version)
 {
-        int cpu;
+        int cpu, max = nr_cpu_ids;
+        bool boot_cpu_detected = physid_isset(boot_cpu_physical_apicid,
+                                phys_cpu_present_map);
+
+        /*
+         * If boot cpu has not been detected yet, then only allow upto
+         * nr_cpu_ids - 1 processors and keep one slot free for boot cpu
+         */
+        if (!boot_cpu_detected && num_processors >= nr_cpu_ids - 1 &&
+            apicid != boot_cpu_physical_apicid) {
+                int thiscpu = max + disabled_cpus - 1;
+
+                pr_warning(
+                        "ACPI: NR_CPUS/possible_cpus limit of %i almost"
+                        " reached. Keeping one slot for boot cpu."
+                        "  Processor %d/0x%x ignored.\n", max, thiscpu, apicid);
+
+                disabled_cpus++;
+                return;
+        }
 
         if (num_processors >= nr_cpu_ids) {
-                int max = nr_cpu_ids;
                 int thiscpu = max + disabled_cpus;
 
                 pr_warning(