x86: Fix VMI && stack protector

commit 7d5b005652bc5ae3e1e0efc53fd0e25a643ec506 upstream.

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>
LKML-Reference: <1249425262.18955.40.camel@ank32.eng.vmware.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/x86/kernel/vmi_32.c b/arch/x86/kernel/vmi_32.c
index 95deb9f2211e98decb5572e4757bc2cc48f3da18..c6a61d2a77f5de510d7e953950e0ebd8e984c978 100644 (file)
--- a/arch/x86/kernel/vmi_32.c
+++ b/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;