| Date | Thu, 01 Jul 2010 10:42:48 -0700 | From | Greg KH <> | Subject | [078/200] powerpc/pseries: Only call start-cpu when a CPU is stopped |
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2.6.34-stable review patch. If anyone has any objections, please let me know.
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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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