From aef40e87d866355ffd279ab21021de733242d0d5 Mon Sep 17 00:00:00 2001
From: Michael Neuling <mikey@neuling.org>
Date: Wed, 28 Apr 2010 13:39:41 +0000
Subject: [PATCH] powerpc/pseries: Only call start-cpu when a CPU is stopped
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>
Cc: <stable@kernel.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
arch/powerpc/platforms/pseries/smp.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 20b694280a66..8979982eb2ee 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -104,6 +104,12 @@ 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;
--
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