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    Subject[patch 059/164] powerpc/pseries: Only call start-cpu when a CPU is stopped
    2.6.33-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Michael Neuling <mikey@neuling.org>

    commit aef40e87d866355ffd279ab21021de733242d0d5 upstream.

    Currently we always call start-cpu irrespective of if the CPU is
    stopped or not. Unfortunatley on POWER7, firmware seems to not like
    start-cpu being called when a cpu already been started. This was not
    the case on POWER6 and earlier.

    This patch checks to see if the CPU is stopped or not via an
    query-cpu-stopped-state call, and only calls start-cpu on CPUs which
    are stopped.

    This fixes a bug with kexec on POWER7 on PHYP where only the primary
    thread would make it to the second kernel.

    Reported-by: Ankita Garg <ankita@linux.vnet.ibm.com>
    Signed-off-by: Michael Neuling <mikey@neuling.org>
    Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    arch/powerpc/platforms/pseries/smp.c | 6 ++++++
    1 file changed, 6 insertions(+)

    --- a/arch/powerpc/platforms/pseries/smp.c
    +++ b/arch/powerpc/platforms/pseries/smp.c
    @@ -82,6 +82,12 @@ static inline int __devinit smp_startup_

    pcpu = get_hard_smp_processor_id(lcpu);

    + /* Check to see if the CPU out of FW already for kexec */
    + if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){
    + cpu_set(lcpu, of_spin_map);
    + return 1;
    + }
    +
    /* Fixup atomic count: it exited inside IRQ handler. */
    task_thread_info(paca[lcpu].__current)->preempt_count = 0;




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