• Thomas Gleixner's avatar
    x86/smpboot: Init apic mapping before usage · 1e90a13d
    Thomas Gleixner authored
    The recent changes, which forced the registration of the boot cpu on UP
    systems, which do not have ACPI tables, have been fixed for systems w/o
    local APIC, but left a wreckage for systems which have neither ACPI nor
    mptables, but the CPU has an APIC, e.g. virtualbox.
    
    The boot process crashes in prefill_possible_map() as it wants to register
    the boot cpu, which needs to access the local apic, but the local APIC is
    not yet mapped.
    
    There is no reason why init_apic_mapping() can't be invoked before
    prefill_possible_map(). So instead of playing another silly early mapping
    game, as the ACPI/mptables code does, we just move init_apic_mapping()
    before the call to prefill_possible_map().
    
    In hindsight, I should have noticed that combination earlier.
    
    Sorry for the churn (also in stable)!
    
    Fixes: ff856051
    
     ("x86/boot/smp: Don't try to poke disabled/non-existent APIC")
    Reported-and-debugged-by: default avatarMichal Necasek <michal.necasek@oracle.com>
    Reported-and-tested-by: default avatarWolfgang Bauer <wbauer@tmo.at>
    Cc: prarit@redhat.com
    Cc: ville.syrjala@linux.intel.com
    Cc: michael.thayer@oracle.com
    Cc: knut.osmundsen@oracle.com
    Cc: frank.mehnert@oracle.com
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: stable@vger.kernel.org
    Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1610282114380.5053@nanos
    
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    1e90a13d