From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: To: Benjamin Herrenschmidt From: Michael Neuling Date: Thu, 29 Apr 2010 09:39:41 +1000 Subject: [PATCH 2/2] powerpc: only call start-cpu when a CPU is stopped Message-Id: <20100428233941.3C4E9CBAF6@localhost.localdomain> Cc: linuxppc-dev@ozlabs.org, ankita@linux.vnet.ibm.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Cc: Signed-off-by: Michael Neuling --- 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;