• Venkatesh Pallipadi's avatar
    [PATCH] Clustered APIC setup for >8 CPU systems · db7b9e9f
    Venkatesh Pallipadi authored
    Clustered APIC setup patch.  Needed to support generic systems with more
    than 8 CPUs.
    
    Motivation:
    
     The current APIC destination mode ("Flat Logical") used in linux kernel
     has an upper limit of 8 CPUs.  For more than 8 CPUs, either "Clustered
     Logical" or "Physical" mode has to be used.
    
     The attached patch adds support such systems by organizing them into
     logical clusters, with each cluster having 4 CPUs.  This is activated by
     a new config option "Support for other sub-arch SMP systems with more
     than 8 CPUs", under Processor feature->Sub architecture.
    
     The patch is made very simple and isolated, thanks to Martin J.
     Bligh's patchsets, which has moved all APIC related functions into
     sub-arch macros.  Has zero impact on standard systems.
    
     This patch enables all 16 logical processors on a generic, non-quad
     based, system that we have here.  Also, by looking at SuSE source, I
     have also added a special switch, to specifically support Unisys
     (ES7000).  Just replacing #define SEQUENTIAL_APICID by CLUSTERED_APICID
     in the patch should make it work on ES7000(not tested).
    db7b9e9f
mach_apic.h 2.4 KB