Do_softirq is invoked at the path of ia64_leave_kernel instead of

being invoking in function irq_exit, which is aligned with XEN/X86 and
avoids __enter_schedule being reentered.

Signed-off-by Anthony Xu <anthony.xu@intel.com>

xen/arch/ia64/linux-xen/entry.S

@@ -895,6 +895,10 @@ GLOBAL_ENTRY(ia64_leave_kernel)
 #endif
 .work_processed_kernel:
 #ifdef XEN
+(pUStk) ssm psr.i
+(pUStk)    br.call.sptk.many b0=process_soft_irq
+(pUStk) rsm psr.i
+    ;;
 	alloc loc0=ar.pfs,0,1,1,0
 	adds out0=16,r12
     adds r7 = PT(EML_UNAT)+16,r12
@@ -907,7 +911,7 @@ leave_kernel_self:
 (p8) br.sptk.few leave_kernel_self
 	;; 
 #endif
-(p6)	br.call.sptk.many b0=deliver_pending_interrupt
+(pUStk)	br.call.sptk.many b0=deliver_pending_interrupt
     ;;
 	mov ar.pfs=loc0
 	mov ar.unat=r7  /* load eml_unat  */

xen/arch/ia64/xen/xenirq.c

@@ -61,16 +61,20 @@ xen_do_IRQ(ia64_vector vector)
  */
 void xen_irq_exit(struct pt_regs *regs)
 {
-	//account_system_vtime(current);
 	sub_preempt_count(IRQ_EXIT_OFFSET);
-    if((((char *)regs) -(char *) current) != (IA64_STK_OFFSET-IA64_PT_REGS_SIZE))
-        return;
+}
 
-	if (!in_interrupt()&&local_softirq_pending()) {
+/*
+ * ONLY gets called from ia64_leave_kernel
+ * ONLY call with interrupts enabled
+ */
+void process_soft_irq()
+{
+	if (!in_interrupt() && local_softirq_pending()) {
 		add_preempt_count(SOFTIRQ_OFFSET);
 		do_softirq();
 		sub_preempt_count(SOFTIRQ_OFFSET);
 	}
-	//preempt_enable_no_resched();
 }
+
 /* end from linux/kernel/softirq.c */