x86: Fix VMI && stack protector

With CONFIG_STACK_PROTECTOR turned on, VMI doesn't boot with
more than one processor. The problem is with the gs value not
being initialized correctly when registering the secondary
processor for VMI's case.

The patch below initializes the gs value for the AP to
__KERNEL_STACK_CANARY. Without this the secondary processor
keeps on taking a GP on every gs access.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Cc: <stable@kernel.org> # for v2.6.30.x
LKML-Reference: <1249425262.18955.40.camel@ank32.eng.vmware.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/vmi_32.c

@@ -441,7 +441,7 @@ vmi_startup_ipi_hook(int phys_apicid, unsigned long start_eip,
 	ap.ds = __USER_DS;
 	ap.es = __USER_DS;
 	ap.fs = __KERNEL_PERCPU;
-	ap.gs = 0;
+	ap.gs = __KERNEL_STACK_CANARY;
 
 	ap.eflags = 0;