• Stefan Kristiansson's avatar
    openrisc: initial SMP support · 8e6d08e0
    Stefan Kristiansson authored
    This patch introduces the SMP support for the OpenRISC architecture.
    The SMP architecture requires cores which have multi-core features which
    have been introduced a few years back including:
    
     - New SPRS SPR_COREID SPR_NUMCORES
     - Shadow SPRs
     - Atomic Instructions
     - Cache Coherency
     - A wired in IPI controller
    
    This patch adds all of the SMP specific changes to core infrastructure,
    it looks big but it needs to go all together as its hard to split this
    one up.
    
    Boot loader spinning of second cpu is not supported yet, it's assumed
    that Linux is booted straight after cpu reset.
    
    The bulk of these changes are trivial changes to refactor to use per cpu
    data structures throughout.  The addition of the smp.c and changes in
    time.c are the changes.  Some specific notes:
    
    MM changes
    ----------
    The reason why this is created as an array, and not with DEFINE_PER_CPU
    is that doing it this way, we'll save a load in the tlb-miss handler
    (the load from __per_cpu_offset).
    
    TLB Flush
    ---------
    The SMP implementation of flush_tlb_* works by sending out a
    function-call IPI to all the non-local cpus by using the generic
    on_each_cpu() function.
    
    Currently, all flush_tlb_* functions will result in a flush_tlb_all(),
    which has always been the behaviour in the UP case.
    
    CPU INFO
    --------
    This creates a per cpu cpuinfo struct and fills it out accordingly for
    each activated cpu.  show_cpuinfo is also updated to reflect new version
    information in later versions of the spec.
    
    SMP API
    -------
    This imitates the arm64 implementation by having a smp_cross_call
    callback that can be set by set_smp_cross_call to initiate an IPI and a
    handle_IPI function that is expected to be called from an IPI irqchip
    driver.
    Signed-off-by: default avatarStefan Kristiansson <stefan.kristiansson@saunalahti.fi>
    [shorne@gmail.com: added cpu stop, checkpatch fixes, wrote commit message]
    Signed-off-by: default avatarStafford Horne <shorne@gmail.com>
    8e6d08e0
spr_defs.h 22.9 KB