diff --git a/arch/i386/pci/acpi.c b/arch/i386/pci/acpi.c
index b33aea8..bc8a44b 100644
--- a/arch/i386/pci/acpi.c
+++ b/arch/i386/pci/acpi.c
@@ -8,20 +8,42 @@
 struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_device *device, int domain, int busnum)
 {
 	struct pci_bus *bus;
+	struct pci_sysdata *sd;
+	int pxm;
 
-	if (domain != 0) {
-		printk(KERN_WARNING "PCI: Multiple domains not supported\n");
+	/* Allocate per-root-bus (not per bus) arch-specific data.
+	 * TODO: leak; this memory is never freed.
+	 * It's arguable whether it's worth the trouble to care.
+	 */
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+	if (!sd) {
+		printk(KERN_ERR "PCI: OOM, not probing PCI bus %02x\n", busnum);
 		return NULL;
 	}
 
-	bus = pcibios_scan_root(busnum);
+	if (domain != 0) {
+		printk(KERN_WARNING "PCI: Multiple domains not supported\n");
+		kfree(sd);
+		return NULL;
+	}
+
+	sd->node = -1;
+
+	pxm = acpi_get_pxm(device->handle);
+#ifdef CONFIG_ACPI_NUMA
+	if (pxm >= 0)
+		sd->node = pxm_to_node(pxm);
+#endif
+
+	bus = pci_scan_bus_parented(NULL, busnum, &pci_root_ops, sd);
+	if (!bus)
+		kfree(sd);
+
 #ifdef CONFIG_ACPI_NUMA
 	if (bus != NULL) {
-		int pxm = acpi_get_pxm(device->handle);
 		if (pxm >= 0) {
-			bus->sysdata = (void *)(unsigned long)pxm_to_node(pxm);
-			printk("bus %d -> pxm %d -> node %ld\n",
-				busnum, pxm, (long)(bus->sysdata));
+			printk("bus %d -> pxm %d -> node %d\n",
+				busnum, pxm, sd->node);
 		}
 	}
 #endif
diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 3f78d4d..85503dee 100644
--- a/arch/i386/pci/common.c
+++ b/arch/i386/pci/common.c
@@ -293,6 +293,7 @@
 struct pci_bus * __devinit pcibios_scan_root(int busnum)
 {
 	struct pci_bus *bus = NULL;
+	struct pci_sysdata *sd;
 
 	dmi_check_system(pciprobe_dmi_table);
 
@@ -303,9 +304,19 @@
 		}
 	}
 
+	/* Allocate per-root-bus (not per bus) arch-specific data.
+	 * TODO: leak; this memory is never freed.
+	 * It's arguable whether it's worth the trouble to care.
+	 */
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+	if (!sd) {
+		printk(KERN_ERR "PCI: OOM, not probing PCI bus %02x\n", busnum);
+		return NULL;
+	}
+
 	printk(KERN_DEBUG "PCI: Probing PCI hardware (bus %02x)\n", busnum);
 
-	return pci_scan_bus_parented(NULL, busnum, &pci_root_ops, NULL);
+	return pci_scan_bus_parented(NULL, busnum, &pci_root_ops, sd);
 }
 
 extern u8 pci_cache_line_size;
diff --git a/arch/x86_64/kernel/pci-calgary.c b/arch/x86_64/kernel/pci-calgary.c
index 21ded20..ba16c96 100644
--- a/arch/x86_64/kernel/pci-calgary.c
+++ b/arch/x86_64/kernel/pci-calgary.c
@@ -373,7 +373,7 @@
 	else
 		pbus = pdev->bus;
 
-	tbl = pbus->self->sysdata;
+	tbl = pci_iommu(pbus);
 
 	BUG_ON(pdev->bus->parent &&
 	       (tbl->it_busno != pdev->bus->parent->number));
@@ -716,7 +716,7 @@
 	limit++;
 
 	numpages = ((limit - start) >> PAGE_SHIFT);
-	iommu_range_reserve(dev->sysdata, start, numpages);
+	iommu_range_reserve(pci_iommu(dev->bus), start, numpages);
 }
 
 static void __init calgary_reserve_peripheral_mem_1(struct pci_dev *dev)
@@ -724,7 +724,7 @@
 	void __iomem *target;
 	u64 low, high, sizelow;
 	u64 start, limit;
-	struct iommu_table *tbl = dev->sysdata;
+	struct iommu_table *tbl = pci_iommu(dev->bus);
 	unsigned char busnum = dev->bus->number;
 	void __iomem *bbar = tbl->bbar;
 
@@ -748,7 +748,7 @@
 	u32 val32;
 	u64 low, high, sizelow, sizehigh;
 	u64 start, limit;
-	struct iommu_table *tbl = dev->sysdata;
+	struct iommu_table *tbl = pci_iommu(dev->bus);
 	unsigned char busnum = dev->bus->number;
 	void __iomem *bbar = tbl->bbar;
 
@@ -784,7 +784,7 @@
 {
 	unsigned int npages;
 	u64 start;
-	struct iommu_table *tbl = dev->sysdata;
+	struct iommu_table *tbl = pci_iommu(dev->bus);
 
 	/* reserve EMERGENCY_PAGES from bad_dma_address and up */
 	iommu_range_reserve(tbl, bad_dma_address, EMERGENCY_PAGES);
@@ -818,7 +818,7 @@
 	if (ret)
 		return ret;
 
-	tbl = dev->sysdata;
+	tbl = pci_iommu(dev->bus);
 	tbl->it_base = (unsigned long)bus_info[dev->bus->number].tce_space;
 	tce_free(tbl, 0, tbl->it_size);
 
@@ -855,7 +855,7 @@
 static void __init calgary_free_bus(struct pci_dev *dev)
 {
 	u64 val64;
-	struct iommu_table *tbl = dev->sysdata;
+	struct iommu_table *tbl = pci_iommu(dev->bus);
 	void __iomem *target;
 	unsigned int bitmapsz;
 
@@ -870,7 +870,8 @@
 	tbl->it_map = NULL;
 
 	kfree(tbl);
-	dev->sysdata = NULL;
+	
+	set_pci_iommu(dev->bus, NULL);
 
 	/* Can't free bootmem allocated memory after system is up :-( */
 	bus_info[dev->bus->number].tce_space = NULL;
@@ -943,7 +944,7 @@
 static void calgary_watchdog(unsigned long data)
 {
 	struct pci_dev *dev = (struct pci_dev *)data;
-	struct iommu_table *tbl = dev->sysdata;
+	struct iommu_table *tbl = pci_iommu(dev->bus);
 	void __iomem *bbar = tbl->bbar;
 	u32 val32;
 	void __iomem *target;
@@ -1041,7 +1042,7 @@
 	struct iommu_table *tbl;
 
 	busnum = dev->bus->number;
-	tbl = dev->sysdata;
+	tbl = pci_iommu(dev->bus);
 	bbar = tbl->bbar;
 
 	/* enable TCE in PHB Config Register */
@@ -1073,7 +1074,7 @@
 	struct iommu_table *tbl;
 
 	busnum = dev->bus->number;
-	tbl = dev->sysdata;
+	tbl = pci_iommu(dev->bus);
 	bbar = tbl->bbar;
 
 	/* disable TCE in PHB Config Register */
@@ -1091,7 +1092,7 @@
 static void __init calgary_init_one_nontraslated(struct pci_dev *dev)
 {
 	pci_dev_get(dev);
-	dev->sysdata = NULL;
+	set_pci_iommu(dev->bus, NULL);
 
 	/* is the device behind a bridge? */
 	if (dev->bus->parent)
@@ -1123,7 +1124,7 @@
 	} else
 		dev->bus->self = dev;
 
-	tbl = dev->sysdata;
+	tbl = pci_iommu(dev->bus);
 	tbl->chip_ops->handle_quirks(tbl, dev);
 
 	calgary_enable_translation(dev);
@@ -1520,7 +1521,7 @@
 	unsigned int npages;
 	int i;
 
-	tbl = dev->sysdata;
+	tbl = pci_iommu(dev->bus);
 
 	for (i = 0; i < 4; i++) {
 		struct resource *r = &dev->resource[PCI_BRIDGE_RESOURCES + i];
diff --git a/arch/x86_64/kernel/tce.c b/arch/x86_64/kernel/tce.c
index f61fb8e..3aeae2f 100644
--- a/arch/x86_64/kernel/tce.c
+++ b/arch/x86_64/kernel/tce.c
@@ -136,9 +136,9 @@
 	struct iommu_table *tbl;
 	int ret;
 
-	if (dev->sysdata) {
-		printk(KERN_ERR "Calgary: dev %p has sysdata %p\n",
-		       dev, dev->sysdata);
+	if (pci_iommu(dev->bus)) {
+		printk(KERN_ERR "Calgary: dev %p has sysdata->iommu %p\n",
+		       dev, pci_iommu(dev->bus));
 		BUG();
 	}
 
@@ -155,11 +155,7 @@
 
 	tbl->bbar = bbar;
 
-	/*
-	 * NUMA is already using the bus's sysdata pointer, so we use
-	 * the bus's pci_dev's sysdata instead.
-	 */
-	dev->sysdata = tbl;
+	set_pci_iommu(dev->bus, tbl);
 
 	return 0;
 
diff --git a/arch/x86_64/pci/k8-bus.c b/arch/x86_64/pci/k8-bus.c
index 3acf60d..9cc813e 100644
--- a/arch/x86_64/pci/k8-bus.c
+++ b/arch/x86_64/pci/k8-bus.c
@@ -59,6 +59,8 @@
 				     j <= SUBORDINATE_LDT_BUS_NUMBER(ldtbus);
 				     j++) { 
 					struct pci_bus *bus;
+					struct pci_sysdata *sd;
+
 					long node = NODE_ID(nid);
 					/* Algorithm a bit dumb, but
  					   it shouldn't matter here */
@@ -67,7 +69,9 @@
 						continue;
 					if (!node_online(node))
 						node = 0;
-					bus->sysdata = (void *)node;
+
+					sd = bus->sysdata;
+					sd->node = node;
 				}		
 			}
 		}
diff --git a/include/asm-i386/pci.h b/include/asm-i386/pci.h
index 392d3fe..d790343 100644
--- a/include/asm-i386/pci.h
+++ b/include/asm-i386/pci.h
@@ -3,6 +3,11 @@
 
 
 #ifdef __KERNEL__
+
+struct pci_sysdata {
+	int		node;		/* NUMA node */
+};
+
 #include <linux/mm.h>		/* for struct page */
 
 /* Can be used to override the logic in pci_scan_bus for skipping
diff --git a/include/asm-i386/topology.h b/include/asm-i386/topology.h
index 7fc512d..19b2daf 100644
--- a/include/asm-i386/topology.h
+++ b/include/asm-i386/topology.h
@@ -67,7 +67,7 @@
 	return first_cpu(mask);
 }
 
-#define pcibus_to_node(bus) ((long) (bus)->sysdata)
+#define pcibus_to_node(bus) ((struct pci_sysdata *)((bus)->sysdata))->node
 #define pcibus_to_cpumask(bus) node_to_cpumask(pcibus_to_node(bus))
 
 /* sched_domains SD_NODE_INIT for NUMAQ machines */
diff --git a/include/asm-x86_64/pci.h b/include/asm-x86_64/pci.h
index bda94fd..88926eb 100644
--- a/include/asm-x86_64/pci.h
+++ b/include/asm-x86_64/pci.h
@@ -5,6 +5,25 @@
 
 #ifdef __KERNEL__
 
+struct pci_sysdata {
+	int		node;		/* NUMA node */
+	void*		iommu;		/* IOMMU private data */
+};
+
+#ifdef CONFIG_CALGARY_IOMMU
+static inline void* pci_iommu(struct pci_bus *bus)
+{
+	struct pci_sysdata *sd = bus->sysdata;
+	return sd->iommu;
+}
+
+static inline void set_pci_iommu(struct pci_bus *bus, void *val)
+{
+	struct pci_sysdata *sd = bus->sysdata;
+	sd->iommu = val;
+}
+#endif /* CONFIG_CALGARY_IOMMU */
+
 #include <linux/mm.h> /* for struct page */
 
 /* Can be used to override the logic in pci_scan_bus for skipping
diff --git a/include/asm-x86_64/topology.h b/include/asm-x86_64/topology.h
index 4fd6fb2..36e52fb 100644
--- a/include/asm-x86_64/topology.h
+++ b/include/asm-x86_64/topology.h
@@ -22,7 +22,7 @@
 #define parent_node(node)		(node)
 #define node_to_first_cpu(node) 	(first_cpu(node_to_cpumask[node]))
 #define node_to_cpumask(node)		(node_to_cpumask[node])
-#define pcibus_to_node(bus)		((long)(bus->sysdata))	
+#define pcibus_to_node(bus)	((struct pci_sysdata *)((bus)->sysdata))->node
 #define pcibus_to_cpumask(bus)		node_to_cpumask(pcibus_to_node(bus));
 
 #define numa_node_id()			read_pda(nodenumber)