[PATCH] x86_64: Increase the maximum number of local APICs to the maximum

This is needed for large multinode IBM systems which have a sparse
APIC space in clustered mode, fully covering the available 8 bits.

The previous kernels would limit the local APIC number to 127,
which caused it to reject some of the CPUs at boot.

I increased the maximum and shrunk the apic_version array a bit
to make up for that (the version is only 8 bit, so don't need
an full int to store)

Cc:  Chris McDermott <lcm@us.ibm.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/x86_64/kernel/mpparse.c

@@ -42,7 +42,7 @@ int acpi_found_madt;
  * Various Linux-internal data structures created from the
  * MP-table.
  */
-int apic_version [MAX_APICS];
+unsigned char apic_version [MAX_APICS];
 unsigned char mp_bus_id_to_type [MAX_MP_BUSSES] = { [0 ... MAX_MP_BUSSES-1] = -1 };
 int mp_bus_id_to_pci_bus [MAX_MP_BUSSES] = { [0 ... MAX_MP_BUSSES-1] = -1 };
 
@@ -108,7 +108,8 @@ static int __init mpf_checksum(unsigned char *mp, int len)
 
 static void __init MP_processor_info (struct mpc_config_processor *m)
 {
-	int ver, cpu;
+	int cpu;
+	unsigned char ver;
 	static int found_bsp=0;
 
 	if (!(m->mpc_cpuflag & CPU_ENABLED)) {
@@ -134,11 +135,13 @@ static void __init MP_processor_info (struct mpc_config_processor *m)
 
 	cpu = num_processors++;
 	
-	if (m->mpc_apicid > MAX_APICS) {
+#if MAX_APICS < 255	
+	if ((int)m->mpc_apicid > MAX_APICS) {
 		printk(KERN_ERR "Processor #%d INVALID. (Max ID: %d).\n",
 			m->mpc_apicid, MAX_APICS);
 		return;
 	}
+#endif
 	ver = m->mpc_apicver;
 
 	physid_set(m->mpc_apicid, phys_cpu_present_map);

include/asm-x86_64/mpspec.h

@@ -16,7 +16,7 @@
 /*
  * A maximum of 255 APICs with the current APIC ID architecture.
  */
-#define MAX_APICS 128
+#define MAX_APICS 255
 
 struct intel_mp_floating
 {
@@ -173,7 +173,7 @@ extern int smp_found_config;
 extern void find_smp_config (void);
 extern void get_smp_config (void);
 extern int nr_ioapics;
-extern int apic_version [MAX_APICS];
+extern unsigned char apic_version [MAX_APICS];
 extern int mp_irq_entries;
 extern struct mpc_config_intsrc mp_irqs [MAX_IRQ_SOURCES];
 extern int mpc_default_type;