GIT: unionfs2-2.6.27.y: powerpc/pseries: Only call start-cpu when a CPU is stopped

[Erez Zadok]

commit 4be4e01c7d844bbb7b88a2bcf931ac00408289c3
Author: Michael Neuling <mikey at neuling.org>
Date:   Wed Apr 28 13:39:41 2010 +0000

    powerpc/pseries: Only call start-cpu when a CPU is stopped
    
    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 at linux.vnet.ibm.com>
    Signed-off-by: Michael Neuling <mikey at neuling.org>
    Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>

diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index c9337c7..5e70fdb 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -84,6 +84,12 @@ static inline int __devinit smp_startup_cpu(unsigned int lcpu)
 
 	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;