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    powerpc/powernv: Fix kexec races going back to OPAL · 298b34d7
    Benjamin Herrenschmidt 提交于
    We have a subtle race when sending CPUs back to OPAL on kexec.
    
    We mark them as "in real mode" right before we send them down. Once
    we've booted the new kernel, it might try to call opal_reinit_cpus()
    to change endianness, and that requires all CPUs to be spinning inside
    OPAL.
    
    However there is no synchronization here and we've observed cases
    where the returning CPUs hadn't established their new state inside
    OPAL before opal_reinit_cpus() is called, causing it to fail.
    
    The proper fix is to actually wait for them to go down all the way
    from the kexec'ing kernel.
    Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
    298b34d7
setup.c 6.2 KB