[PATCH] x86_64: Remove unique APIC/IO-APIC ID check

It is unnecessary on modern Intel or AMD systems, and that is all we support
on x86-64

Also causes problems on various systems

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/io_apic.c

@@ -1804,76 +1804,6 @@ device_initcall(ioapic_init_sysfs);
 
 #define IO_APIC_MAX_ID		0xFE
 
-int __init io_apic_get_unique_id (int ioapic, int apic_id)
-{
-	union IO_APIC_reg_00 reg_00;
-	static physid_mask_t apic_id_map;
-	unsigned long flags;
-	int i = 0;
-
-	/*
-	 * The P4 platform supports up to 256 APIC IDs on two separate APIC 
-	 * buses (one for LAPICs, one for IOAPICs), where predecessors only 
-	 * supports up to 16 on one shared APIC bus.
-	 * 
-	 * TBD: Expand LAPIC/IOAPIC support on P4-class systems to take full
-	 *      advantage of new APIC bus architecture.
-	 */
-
-	if (physids_empty(apic_id_map))
-		apic_id_map = phys_cpu_present_map;
-
-	spin_lock_irqsave(&ioapic_lock, flags);
-	reg_00.raw = io_apic_read(ioapic, 0);
-	spin_unlock_irqrestore(&ioapic_lock, flags);
-
-	if (apic_id >= IO_APIC_MAX_ID) {
-		apic_printk(APIC_QUIET, KERN_WARNING "IOAPIC[%d]: Invalid apic_id %d, trying "
-			"%d\n", ioapic, apic_id, reg_00.bits.ID);
-		apic_id = reg_00.bits.ID;
-	}
-
-	/*
-	 * 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 (physid_isset(apic_id, apic_id_map)) {
-
-		for (i = 0; i < IO_APIC_MAX_ID; i++) {
-			if (!physid_isset(i, apic_id_map))
-				break;
-		}
-
-		if (i == IO_APIC_MAX_ID)
-			panic("Max apic_id exceeded!\n");
-
-		apic_printk(APIC_VERBOSE, KERN_WARNING "IOAPIC[%d]: apic_id %d already used, "
-			"trying %d\n", ioapic, apic_id, i);
-
-		apic_id = i;
-	} 
-
-	physid_set(apic_id, apic_id_map);
-
-	if (reg_00.bits.ID != apic_id) {
-		reg_00.bits.ID = apic_id;
-
-		spin_lock_irqsave(&ioapic_lock, flags);
-		io_apic_write(ioapic, 0, reg_00.raw);
-		reg_00.raw = io_apic_read(ioapic, 0);
-		spin_unlock_irqrestore(&ioapic_lock, flags);
-
-		/* Sanity check */
-		if (reg_00.bits.ID != apic_id)
-			panic("IOAPIC[%d]: Unable change apic_id!\n", ioapic);
-	}
-
-	apic_printk(APIC_VERBOSE,KERN_INFO "IOAPIC[%d]: Assigned apic_id %d\n", ioapic, apic_id);
-
-	return apic_id;
-}
-
-
 int __init io_apic_get_version (int ioapic)
 {
 	union IO_APIC_reg_01	reg_01;

arch/x86_64/kernel/mpparse.c

@@ -759,7 +759,7 @@ void __init mp_register_ioapic (
 	mp_ioapics[idx].mpc_apicaddr = address;
 
 	set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
-	mp_ioapics[idx].mpc_apicid = io_apic_get_unique_id(idx, id);
+	mp_ioapics[idx].mpc_apicid = id;
 	mp_ioapics[idx].mpc_apicver = io_apic_get_version(idx);
 
 	/* 

include/asm-x86_64/io_apic.h

@@ -202,7 +202,6 @@ extern int skip_ioapic_setup;
 #define io_apic_assign_pci_irqs (mp_irq_entries && !skip_ioapic_setup && io_apic_irqs)
 
 #ifdef CONFIG_ACPI_BOOT
-extern int io_apic_get_unique_id (int ioapic, int apic_id);
 extern int io_apic_get_version (int ioapic);
 extern int io_apic_get_redir_entries (int ioapic);
 extern int io_apic_set_pci_routing (int ioapic, int pin, int irq, int, int);