x86: put trigger in to detect mismatched apic versions

Impact: add debug warning

Fire off one message if two apic's discovered with different
apic versions. (this code is only called during CPU init)

The goal of this is to pave the way of the removal of the apic_version[]
array. We dont expect any apic version incompatibilities in the x86
landscape of systems [if so we dont handle them very well and probably
never will handle deep apic version assymetries well], but it's prudent
to have a debug check for one kernel cycle nevertheless.

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c
index d19aa3aab62b..4b6df2469fe3 100644
--- a/arch/x86/kernel/apic.c
+++ b/arch/x86/kernel/apic.c
@@ -1837,6 +1837,11 @@ void __cpuinit generic_processor_info(int apicid, int version)
         num_processors++;
         cpu = cpumask_next_zero(-1, cpu_present_mask);
 
+        if (version != apic_version[boot_cpu_physical_apicid])
+                WARN_ONCE(1,
+                        "ACPI: apic version mismatch, bootcpu: %x cpu %d: %x\n",
+                        apic_version[boot_cpu_physical_apicid], cpu, version);
+
         physid_set(apicid, phys_cpu_present_map);
         if (apicid == boot_cpu_physical_apicid) {
                 /*