+#ifdef CONFIG_X86_32
+/*
+ * function to set the IO-APIC physical IDs based on the
+ * values stored in the MPC table.
+ *
+ * by Matt Domsch <Matt_Domsch@dell.com> Tue Dec 21 12:25:05 CST 1999
+ */
+
+static void __init setup_ioapic_ids_from_mpc(void)
+{
+ union IO_APIC_reg_00 reg_00;
+ physid_mask_t phys_id_present_map;
+ int apic;
+ int i;
+ unsigned char old_id;
+ unsigned long flags;
+
+ if (x86_quirks->setup_ioapic_ids && x86_quirks->setup_ioapic_ids())
+ return;
+
+ /*
+ * Don't check I/O APIC IDs for xAPIC systems. They have
+ * no meaning without the serial APIC bus.
+ */
+ if (!(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+ || APIC_XAPIC(apic_version[boot_cpu_physical_apicid]))
+ return;
+ /*
+ * This is broken; anything with a real cpu count has to
+ * circumvent this idiocy regardless.
+ */
+ phys_id_present_map = ioapic_phys_id_map(phys_cpu_present_map);
+
+ /*
+ * Set the IOAPIC ID to the value stored in the MPC table.
+ */
+ for (apic = 0; apic < nr_ioapics; apic++) {
+
+ /* Read the register 0 value */
+ spin_lock_irqsave(&ioapic_lock, flags);
+ reg_00.raw = io_apic_read(apic, 0);
+ spin_unlock_irqrestore(&ioapic_lock, flags);
+
+ old_id = mp_ioapics[apic].mp_apicid;
+
+ if (mp_ioapics[apic].mp_apicid >= get_physical_broadcast()) {
+ printk(KERN_ERR "BIOS bug, IO-APIC#%d ID is %d in the MPC table!...\n",
+ apic, mp_ioapics[apic].mp_apicid);
+ printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
+ reg_00.bits.ID);
+ mp_ioapics[apic].mp_apicid = reg_00.bits.ID;
+ }
+
+ /*
+ * Sanity check, is the ID really free? Every APIC in a
+ * system must have a unique ID or we get lots of nice
+ * 'stuck on smp_invalidate_needed IPI wait' messages.
+ */
+ if (check_apicid_used(phys_id_present_map,
+ mp_ioapics[apic].mp_apicid)) {
+ printk(KERN_ERR "BIOS bug, IO-APIC#%d ID %d is already used!...\n",
+ apic, mp_ioapics[apic].mp_apicid);
+ for (i = 0; i < get_physical_broadcast(); i++)
+ if (!physid_isset(i, phys_id_present_map))
+ break;
+ if (i >= get_physical_broadcast())
+ panic("Max APIC ID exceeded!\n");
+ printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
+ i);
+ physid_set(i, phys_id_present_map);
+ mp_ioapics[apic].mp_apicid = i;
+ } else {
+ physid_mask_t tmp;
+ tmp = apicid_to_cpu_present(mp_ioapics[apic].mp_apicid);
+ apic_printk(APIC_VERBOSE, "Setting %d in the "
+ "phys_id_present_map\n",
+ mp_ioapics[apic].mp_apicid);
+ physids_or(phys_id_present_map, phys_id_present_map, tmp);
+ }
+
+
+ /*
+ * We need to adjust the IRQ routing table
+ * if the ID changed.
+ */
+ if (old_id != mp_ioapics[apic].mp_apicid)
+ for (i = 0; i < mp_irq_entries; i++)
+ if (mp_irqs[i].mp_dstapic == old_id)
+ mp_irqs[i].mp_dstapic
+ = mp_ioapics[apic].mp_apicid;
+
+ /*
+ * Read the right value from the MPC table and
+ * write it into the ID register.
+ */
+ apic_printk(APIC_VERBOSE, KERN_INFO
+ "...changing IO-APIC physical APIC ID to %d ...",
+ mp_ioapics[apic].mp_apicid);
+
+ reg_00.bits.ID = mp_ioapics[apic].mp_apicid;
+ spin_lock_irqsave(&ioapic_lock, flags);
+
+ /*
+ * Sanity check
+ */
+ spin_lock_irqsave(&ioapic_lock, flags);
+ reg_00.raw = io_apic_read(apic, 0);
+ spin_unlock_irqrestore(&ioapic_lock, flags);
+ if (reg_00.bits.ID != mp_ioapics[apic].mp_apicid)
+ printk("could not set ID!\n");
+ else
+ apic_printk(APIC_VERBOSE, " ok.\n");
+ }
+}
+#endif
+