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List: linuxppc-embedded
Subject: [PATCH 2/2] powerpc: only call start-cpu when a CPU is stopped
From: Michael Neuling <mikey () neuling ! org>
Date: 2010-04-28 23:39:41
Message-ID: 20100428233941.3C4E9CBAF6 () localhost ! localdomain
[Download RAW message or body]
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>
---
arch/powerpc/platforms/pseries/smp.c | 6 ++++++
1 file changed, 6 insertions(+)
Index: linux-2.6-ozlabs/arch/powerpc/platforms/pseries/smp.c
===================================================================
--- linux-2.6-ozlabs.orig/arch/powerpc/platforms/pseries/smp.c
+++ linux-2.6-ozlabs/arch/powerpc/platforms/pseries/smp.c
@@ -103,6 +103,12 @@ static inline int __devinit smp_startup_
return 1;
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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