x86: introduce max_physical_apicid for bigsmp switching

a multi-socket test-system with 3 or 4 ioapics, when 4 dualcore cpus or
2 quadcore cpus installed, needs to switch to bigsmp or physflat.

CPU apic id is [4,11] instead of [0,7], and we need to check max apic
id instead of cpu numbers.

also add check for 32 bit when acpi is not compiled in or acpi=off.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 0a281f2c7157..45a5e247d450 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -17,6 +17,7 @@ unsigned int num_processors;
 unsigned disabled_cpus __cpuinitdata;
 /* Processor that is doing the boot up */
 unsigned int boot_cpu_physical_apicid = -1U;
+unsigned int max_physical_apicid;
 EXPORT_SYMBOL(boot_cpu_physical_apicid);
 
 DEFINE_PER_CPU(u16, x86_cpu_to_apicid) = BAD_APICID;