powerpc: Reduce footprint of irq_stat

Index: linux-cpumask/arch/powerpc/include/asm/hardirq.h
===================================================================
@@ -1 +1,22 @@
-#include <asm-generic/hardirq.h>
+#ifndef _ASM_POWERPC_HARDIRQ_H
+#define _ASM_POWERPC_HARDIRQ_H
+
+#include <linux/threads.h>
+#include <linux/irq.h>
+
+typedef struct {
+	unsigned int __softirq_pending;
+} ____cacheline_aligned irq_cpustat_t;
+
+DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+
+#define __ARCH_IRQ_STAT
+
+#define local_softirq_pending()	__get_cpu_var(irq_stat).__softirq_pending
+
+static inline void ack_bad_irq(unsigned int irq)
+{
+	printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
+}
+
+#endif /* _ASM_POWERPC_HARDIRQ_H */

Index: linux-cpumask/arch/powerpc/kernel/irq.c
===================================================================
@@ -73,6 +73,9 @@
 #define CREATE_TRACE_POINTS
 #include <asm/trace.h>
 
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
+
 int __irq_offset_value;
 static int ppc_spurious_interrupts;
 

Index: linux-cpumask/arch/powerpc/include/asm/hardirq.h
===================================================================
@@ -6,6 +6,9 @@
 
 typedef struct {
 	unsigned int __softirq_pending;
+#if defined(CONFIG_XICS) && defined(CONFIG_SMP)
+	unsigned long xics_ipi;
+#endif
 } ____cacheline_aligned irq_cpustat_t;
 
 DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);

Index: linux-cpumask/arch/powerpc/platforms/pseries/xics.c
===================================================================
@@ -514,15 +514,12 @@ static void __init xics_init_host(void)
 /*
  * XICS only has a single IPI, so encode the messages per CPU
  */
-struct xics_ipi_struct {
-        unsigned long value;
-	} ____cacheline_aligned;
-
-static struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;
 
 static inline void smp_xics_do_message(int cpu, int msg)
 {
-	set_bit(msg, &xics_ipi_message[cpu].value);
+	unsigned long *tgt = &(per_cpu(irq_stat, cpu).xics_ipi);
+
+	set_bit(msg, tgt);
 	mb();
 	if (firmware_has_feature(FW_FEATURE_LPAR))
 		lpar_qirr_info(cpu, IPI_PRIORITY);

@@ -548,25 +545,23 @@ void smp_xics_message_pass(int target, i
 
 static irqreturn_t xics_ipi_dispatch(int cpu)
 {
+	unsigned long *tgt = &(per_cpu(irq_stat, cpu).xics_ipi);
+
 	WARN_ON(cpu_is_offline(cpu));
 
 	mb();	/* order mmio clearing qirr */
-	while (xics_ipi_message[cpu].value) {
-		if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
-				       &xics_ipi_message[cpu].value)) {
+	while (*tgt) {
+		if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, tgt)) {
 			smp_message_recv(PPC_MSG_CALL_FUNCTION);
 		}
-		if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
-				       &xics_ipi_message[cpu].value)) {
+		if (test_and_clear_bit(PPC_MSG_RESCHEDULE, tgt)) {
 			smp_message_recv(PPC_MSG_RESCHEDULE);
 		}
-		if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE,
-				       &xics_ipi_message[cpu].value)) {
+		if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, tgt)) {
 			smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
 		}
 #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
-		if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
-				       &xics_ipi_message[cpu].value)) {
+		if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, tgt)) {
 			smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
 		}
 #endif