• Vineet Gupta's avatar
    ARC: SMP support · 41195d23
    Vineet Gupta authored
    ARC common code to enable a SMP system + ISS provided SMP extensions.
    
    ARC700 natively lacks SMP support, hence some of the core features are
    are only enabled if SoCs have the necessary h/w pixie-dust. This
    includes:
    -Inter Processor Interrupts (IPI)
    -Cache coherency
    -load-locked/store-conditional
    ...
    
    The low level exception handling would be completely broken in SMP
    because we don't have hardware assisted stack switching. Thus a fair bit
    of this code is repurposing the MMU_SCRATCH reg for event handler
    prologues to keep them re-entrant.
    
    Many thanks to Rajeshwar Ranga for his initial "major" contributions to
    SMP Port (back in 2008), and to Noam Camus and Gilad Ben-Yossef for help
    with resurrecting that in 3.2 kernel (2012).
    
    Note that this platform code is again singleton design pattern - so
    multiple SMP platforms won't build at the moment - this deficiency is
    addressed in subsequent patches within this series.
    Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Rajeshwar Ranga <rajeshwar.ranga@gmail.com>
    Cc: Noam Camus <noamc@ezchip.com>
    Cc: Gilad Ben-Yossef <gilad@benyossef.com>
    41195d23
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