+#ifdef HAVE_X2APIC
+void check_x2apic(void)
+{
+ int msr, msr2;
+
+ rdmsr(MSR_IA32_APICBASE, msr, msr2);
+
+ if (msr & X2APIC_ENABLE) {
+ printk("x2apic enabled by BIOS, switching to x2apic ops\n");
+ x2apic_preenabled = x2apic = 1;
+ apic_ops = &x2apic_ops;
+ }
+}
+
+void enable_x2apic(void)
+{
+ int msr, msr2;
+
+ rdmsr(MSR_IA32_APICBASE, msr, msr2);
+ if (!(msr & X2APIC_ENABLE)) {
+ printk("Enabling x2apic\n");
+ wrmsr(MSR_IA32_APICBASE, msr | X2APIC_ENABLE, 0);
+ }
+}
+
+void enable_IR_x2apic(void)
+{
+#ifdef CONFIG_INTR_REMAP
+ int ret;
+ unsigned long flags;
+
+ if (!cpu_has_x2apic)
+ return;
+
+ if (!x2apic_preenabled && disable_x2apic) {
+ printk(KERN_INFO
+ "Skipped enabling x2apic and Interrupt-remapping "
+ "because of nox2apic\n");
+ return;
+ }
+
+ if (x2apic_preenabled && disable_x2apic)
+ panic("Bios already enabled x2apic, can't enforce nox2apic");
+
+ if (!x2apic_preenabled && skip_ioapic_setup) {
+ printk(KERN_INFO
+ "Skipped enabling x2apic and Interrupt-remapping "
+ "because of skipping io-apic setup\n");
+ return;
+ }
+
+ ret = dmar_table_init();
+ if (ret) {
+ printk(KERN_INFO
+ "dmar_table_init() failed with %d:\n", ret);
+
+ if (x2apic_preenabled)
+ panic("x2apic enabled by bios. But IR enabling failed");
+ else
+ printk(KERN_INFO
+ "Not enabling x2apic,Intr-remapping\n");
+ return;
+ }
+
+ local_irq_save(flags);
+ mask_8259A();
+ save_mask_IO_APIC_setup();
+
+ ret = enable_intr_remapping(1);
+
+ if (ret && x2apic_preenabled) {
+ local_irq_restore(flags);
+ panic("x2apic enabled by bios. But IR enabling failed");
+ }
+
+ if (ret)
+ goto end;
+
+ if (!x2apic) {
+ x2apic = 1;
+ apic_ops = &x2apic_ops;
+ enable_x2apic();
+ }
+end:
+ if (ret)
+ /*
+ * IR enabling failed
+ */
+ restore_IO_APIC_setup();
+ else
+ reinit_intr_remapped_IO_APIC(x2apic_preenabled);
+
+ unmask_8259A();
+ local_irq_restore(flags);
+
+ if (!ret) {
+ if (!x2apic_preenabled)
+ printk(KERN_INFO
+ "Enabled x2apic and interrupt-remapping\n");
+ else
+ printk(KERN_INFO
+ "Enabled Interrupt-remapping\n");
+ } else
+ printk(KERN_ERR
+ "Failed to enable Interrupt-remapping and x2apic\n");
+#else
+ if (!cpu_has_x2apic)
+ return;
+
+ if (x2apic_preenabled)
+ panic("x2apic enabled prior OS handover,"
+ " enable CONFIG_INTR_REMAP");
+
+ printk(KERN_INFO "Enable CONFIG_INTR_REMAP for enabling intr-remapping "
+ " and x2apic\n");
+#endif
+
+ return;
+}
+#endif /* HAVE_X2APIC */
+