diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 736d45602886ea7b08024f246f06e9c7c6dc1a05..51bceb0fb2778564b0dd5383fa13cbbfdad1ad6c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1772,6 +1772,12 @@ and is between 256 and 4096 characters. It is defined in the file
 			purges which is reported from either PAL_VM_SUMMARY or
 			SAL PALO.
 
+	nr_cpus=	[SMP] Maximum number of processors that	an SMP kernel
+			could support.  nr_cpus=n : n >= 1 limits the kernel to
+			supporting 'n' processors. Later in runtime you can not
+			use hotplug cpu feature to put more cpu back to online.
+			just like you compile the kernel NR_CPUS=n
+
 	nr_uarts=	[SERIAL] maximum number of UARTs to be registered.
 
 	numa_zonelist_order= [KNL, BOOT] Select zonelist order for NUMA.
diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index 40574ae114018e4db5efce7fc499435c4c863eec..605a08b29721eca160672484a76aa5a90b8adee3 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -881,8 +881,8 @@ __init void prefill_possible_map(void)
 
 	possible = available_cpus + additional_cpus;
 
-	if (possible > NR_CPUS)
-		possible = NR_CPUS;
+	if (possible > nr_cpu_ids)
+		possible = nr_cpu_ids;
 
 	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
 		possible, max((possible - available_cpus), 0));
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 678d0b8c26f3152c67a833f3e782cb15c9d0a61b..eff2fe175422bb45f6926d349fee2e2043130f97 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1213,11 +1213,12 @@ __init void prefill_possible_map(void)
 
 	total_cpus = max_t(int, possible, num_processors + disabled_cpus);
 
-	if (possible > CONFIG_NR_CPUS) {
+	/* nr_cpu_ids could be reduced via nr_cpus= */
+	if (possible > nr_cpu_ids) {
 		printk(KERN_WARNING
 			"%d Processors exceeds NR_CPUS limit of %d\n",
-			possible, CONFIG_NR_CPUS);
-		possible = CONFIG_NR_CPUS;
+			possible, nr_cpu_ids);
+		possible = nr_cpu_ids;
 	}
 
 	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 7ad48dfc12dbc838ab82275517e5521463c4319b..b8725461d8874aec865d8617f1c5c1ef70ae1bae 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -279,9 +279,9 @@ int __init acpi_numa_init(void)
 	/* SRAT: Static Resource Affinity Table */
 	if (!acpi_table_parse(ACPI_SIG_SRAT, acpi_parse_srat)) {
 		acpi_table_parse_srat(ACPI_SRAT_TYPE_X2APIC_CPU_AFFINITY,
-				      acpi_parse_x2apic_affinity, NR_CPUS);
+				     acpi_parse_x2apic_affinity, nr_cpu_ids);
 		acpi_table_parse_srat(ACPI_SRAT_TYPE_CPU_AFFINITY,
-				      acpi_parse_processor_affinity, NR_CPUS);
+				     acpi_parse_processor_affinity, nr_cpu_ids);
 		ret = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
 					    acpi_parse_memory_affinity,
 					    NR_NODE_MEMBLKS);
diff --git a/init/main.c b/init/main.c
index 845187822e5cd2ea990d6a04233b24e5c082abbc..05b5283e98fab4b5666134c1612c44bfaf36a51b 100644
--- a/init/main.c
+++ b/init/main.c
@@ -149,6 +149,20 @@ static int __init nosmp(char *str)
 
 early_param("nosmp", nosmp);
 
+/* this is hard limit */
+static int __init nrcpus(char *str)
+{
+	int nr_cpus;
+
+	get_option(&str, &nr_cpus);
+	if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
+		nr_cpu_ids = nr_cpus;
+
+	return 0;
+}
+
+early_param("nr_cpus", nrcpus);
+
 static int __init maxcpus(char *str)
 {
 	get_option(&str, &setup_max_cpus);