1 files changed, 40 insertions, 22 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b9338b8cf420..a2fd72e0ab35 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -27,6 +27,7 @@
 #include <linux/syscore_ops.h>
 #include <linux/delay.h>
 #include <linux/timex.h>
+#include <linux/i8253.h>
 #include <linux/dmar.h>
 #include <linux/init.h>
 #include <linux/cpu.h>
@@ -37,9 +38,8 @@
 #include <asm/perf_event.h>
 #include <asm/x86_init.h>
 #include <asm/pgalloc.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
 #include <asm/mpspec.h>
-#include <asm/i8253.h>
 #include <asm/i8259.h>
 #include <asm/proto.h>
 #include <asm/apic.h>
@@ -48,6 +48,7 @@
 #include <asm/hpet.h>
 #include <asm/idle.h>
 #include <asm/mtrr.h>
+#include <asm/time.h>
 #include <asm/smp.h>
 #include <asm/mce.h>
 #include <asm/tsc.h>
@@ -1429,34 +1430,28 @@ void enable_x2apic(void)
 	rdmsr(MSR_IA32_APICBASE, msr, msr2);
 	if (!(msr & X2APIC_ENABLE)) {
 		printk_once(KERN_INFO "Enabling x2apic\n");
-		wrmsr(MSR_IA32_APICBASE, msr | X2APIC_ENABLE, 0);
+		wrmsr(MSR_IA32_APICBASE, msr | X2APIC_ENABLE, msr2);
 	}
 }
 #endif /* CONFIG_X86_X2APIC */
 
 int __init enable_IR(void)
 {
-#ifdef CONFIG_INTR_REMAP
+#ifdef CONFIG_IRQ_REMAP
 	if (!intr_remapping_supported()) {
 		pr_debug("intr-remapping not supported\n");
-		return 0;
+		return -1;
 	}
 
 	if (!x2apic_preenabled && skip_ioapic_setup) {
 		pr_info("Skipped enabling intr-remap because of skipping "
 			"io-apic setup\n");
-		return 0;
+		return -1;
 	}
 
-	if (enable_intr_remapping(x2apic_supported()))
-		return 0;
-
-	pr_info("Enabled Interrupt-remapping\n");
-
-	return 1;
-
+	return enable_intr_remapping();
 #endif
-	return 0;
+	return -1;
 }
 
 void __init enable_IR_x2apic(void)
@@ -1480,11 +1475,11 @@ void __init enable_IR_x2apic(void)
 	mask_ioapic_entries();
 
 	if (dmar_table_init_ret)
-		ret = 0;
+		ret = -1;
 	else
 		ret = enable_IR();
 
-	if (!ret) {
+	if (ret < 0) {
 		/* IR is required if there is APIC ID > 255 even when running
 		 * under KVM
 		 */
@@ -1498,6 +1493,9 @@ void __init enable_IR_x2apic(void)
 		x2apic_force_phys();
 	}
 
+	if (ret == IRQ_REMAP_XAPIC_MODE)
+		goto nox2apic;
+
 	x2apic_enabled = 1;
 
 	if (x2apic_supported() && !x2apic_mode) {
@@ -1507,19 +1505,21 @@ void __init enable_IR_x2apic(void)
 	}
 
 nox2apic:
-	if (!ret) /* IR enabling failed */
+	if (ret < 0) /* IR enabling failed */
 		restore_ioapic_entries();
 	legacy_pic->restore_mask();
 	local_irq_restore(flags);
 
 out:
-	if (x2apic_enabled)
+	if (x2apic_enabled || !x2apic_supported())
 		return;
 
 	if (x2apic_preenabled)
 		panic("x2apic: enabled by BIOS but kernel init failed.");
-	else if (cpu_has_x2apic)
-		pr_info("Not enabling x2apic, Intr-remapping init failed.\n");
+	else if (ret == IRQ_REMAP_XAPIC_MODE)
+		pr_info("x2apic not enabled, IRQ remapping is in xapic mode\n");
+	else if (ret < 0)
+		pr_info("x2apic not enabled, IRQ remapping init failed\n");
 }
 
 #ifdef CONFIG_X86_64
@@ -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(