[POWERPC] Split xics_teardown_cpu()

This splits off the kexec path bits of the xics_teardown_cpu() routine
into its own xics_kexec_teardown_cpu() routine.  With the previous
combined routine the CPPR for a cpu that is being removed may have its
CPPR reset in the plpar_eoi() call (which explicitly sets the CPPR to
a non-zero value).  Splitting of the kexec bits of the code prevents
this from happening in the cpu remove path.

Once again, this does not cause the cpu remove from the kernel to
fail, but it does cause cpu dlpar operations to not be able to return
the cpu to the hypervisor.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/platforms/pseries/hotplug-cpu.c

@@ -58,7 +58,7 @@ static void pseries_mach_cpu_die(void)
 {
 	local_irq_disable();
 	idle_task_exit();
-	xics_teardown_cpu(0);
+	xics_teardown_cpu();
 	unregister_slb_shadow(hard_smp_processor_id(), __pa(get_slb_shadow()));
 	rtas_stop_self();
 	/* Should never get here... */

arch/powerpc/platforms/pseries/kexec.c

@@ -54,7 +54,7 @@ void __init setup_kexec_cpu_down_mpic(void)
 static void pseries_kexec_cpu_down_xics(int crash_shutdown, int secondary)
 {
 	pseries_kexec_cpu_down(crash_shutdown, secondary);
-	xics_teardown_cpu(secondary);
+	xics_kexec_teardown_cpu(secondary);
 }
 
 void __init setup_kexec_cpu_down_xics(void)

arch/powerpc/platforms/pseries/xics.c

@@ -775,11 +775,9 @@ void xics_request_IPIs(void)
 }
 #endif /* CONFIG_SMP */
 
-void xics_teardown_cpu(int secondary)
+void xics_teardown_cpu()
 {
 	int cpu = smp_processor_id();
-	unsigned int ipi;
-	struct irq_desc *desc;
 
 	xics_set_cpu_priority(0);
 
@@ -790,9 +788,17 @@ void xics_teardown_cpu(int secondary)
 		lpar_qirr_info(cpu, 0xff);
 	else
 		direct_qirr_info(cpu, 0xff);
+}
+
+void xics_kexec_teardown_cpu(int secondary)
+{
+	unsigned int ipi;
+	struct irq_desc *desc;
+
+	xics_teardown_cpu();
 
 	/*
-	 * we need to EOI the IPI if we got here from kexec down IPI
+	 * we need to EOI the IPI
 	 *
 	 * probably need to check all the other interrupts too
 	 * should we be flagging idle loop instead?

arch/powerpc/platforms/pseries/xics.h

@@ -16,7 +16,8 @@
 
 extern void xics_init_IRQ(void);
 extern void xics_setup_cpu(void);
-extern void xics_teardown_cpu(int secondary);
+extern void xics_teardown_cpu(void);
+extern void xics_kexec_teardown_cpu(int secondary);
 extern void xics_cause_IPI(int cpu);
 extern  void xics_request_IPIs(void);
 extern void xics_migrate_irqs_away(void);