x86, apic: Fix apic=debug boot crash

Fix a boot crash when apic=debug is used and the APIC is
not properly initialized.

This issue appears during Xen Dom0 kernel boot but the
fix is generic and the crash could occur on real hardware
as well.

Signed-off-by: Daniel Kiper <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: <[email protected]> # .35.x, .34.x, .33.x, .32.x
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
1 file changed