[078/200] powerpc/pseries: Only call start-cpu when a CPU is stopped
diff mbox series

Message ID 20100701174252.999570212@clark.site
State New, archived
Headers show
Series
  • 2.6.34.1 stable review
Related show

Commit Message

Greg KH July 1, 2010, 5:42 p.m. UTC
2.6.34-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(+)



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Patch
diff mbox series

--- 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;