Index: xen-4.0.1-testing/unmodified_drivers/linux-2.6/platform-pci/evtchn.c
===================================================================
--- xen-4.0.1-testing.orig/unmodified_drivers/linux-2.6/platform-pci/evtchn.c
+++ xen-4.0.1-testing/unmodified_drivers/linux-2.6/platform-pci/evtchn.c
@@ -40,7 +40,9 @@
 #include <xen/platform-compat.h>
 #endif
 
+#ifndef shared_info_area
 void *shared_info_area;
+#endif
 
 #define is_valid_evtchn(x)	((x) != 0)
 #define evtchn_from_irq(x)	(irq_evtchn[irq].evtchn)
Index: xen-4.0.1-testing/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
===================================================================
--- xen-4.0.1-testing.orig/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
+++ xen-4.0.1-testing/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
@@ -77,7 +77,6 @@ static uint64_t callback_via;
 static int __devinit init_xen_info(void)
 {
 	struct xen_add_to_physmap xatp;
-	extern void *shared_info_area;
 
 #ifdef __ia64__
 	xencomm_initialize();
@@ -85,6 +84,7 @@ static int __devinit init_xen_info(void)
 
 	setup_xen_features();
 
+#ifndef shared_info_area
 	shared_info_frame = alloc_xen_mmio(PAGE_SIZE) >> PAGE_SHIFT;
 	xatp.domid = DOMID_SELF;
 	xatp.idx = 0;
@@ -97,6 +97,11 @@ static int __devinit init_xen_info(void)
 		ioremap(shared_info_frame << PAGE_SHIFT, PAGE_SIZE);
 	if (shared_info_area == NULL)
 		panic("can't map shared info\n");
+#else
+	shared_info_frame = __pa(shared_info_area) >> PAGE_SHIFT;
+	printk(KERN_INFO "Using kernel provided shared info (pfn=%lx)\n",
+	       shared_info_frame);
+#endif
 
 	return 0;
 }
Index: xen-4.0.1-testing/unmodified_drivers/linux-2.6/platform-pci/platform-pci.h
===================================================================
--- xen-4.0.1-testing.orig/unmodified_drivers/linux-2.6/platform-pci/platform-pci.h
+++ xen-4.0.1-testing/unmodified_drivers/linux-2.6/platform-pci/platform-pci.h
@@ -27,6 +27,11 @@
 unsigned long alloc_xen_mmio(unsigned long len);
 void platform_pci_resume(void);
 
+#ifdef CONFIG_ENLIGHTEN_SPINLOCKS
+#define shared_info_area xen_shared_info
+#endif
+extern void *shared_info_area;
+
 extern struct pci_dev *xen_platform_pdev;
 
 #endif /* _XEN_PLATFORM_PCI_H */