diff --git a/arch/sparc64/kernel/ds.c b/arch/sparc64/kernel/ds.c
index c7ece8c52039..9c8839d1cffd 100644
--- a/arch/sparc64/kernel/ds.c
+++ b/arch/sparc64/kernel/ds.c
@@ -15,6 +15,7 @@
 #include <asm/ldc.h>
 #include <asm/vio.h>
 #include <asm/power.h>
+#include <asm/mdesc.h>
 
 #define DRV_MODULE_NAME		"ds"
 #define PFX DRV_MODULE_NAME	": "
@@ -170,8 +171,7 @@ static void md_update_data(struct ldc_channel *lp,
 
 	rp = (struct ds_md_update_req *) (dpkt + 1);
 
-	printk(KERN_ERR PFX "MD update REQ [%lx] len=%d\n",
-	       rp->req_num, len);
+	printk(KERN_ERR PFX "Machine description update.\n");
 
 	memset(&pkt, 0, sizeof(pkt));
 	pkt.data.tag.type = DS_DATA;
@@ -181,6 +181,8 @@ static void md_update_data(struct ldc_channel *lp,
 	pkt.res.result = DS_OK;
 
 	ds_send(lp, &pkt, sizeof(pkt));
+
+	mdesc_update();
 }
 
 struct ds_shutdown_req {
@@ -555,7 +557,6 @@ static int __devinit ds_probe(struct vio_dev *vdev,
 			      const struct vio_device_id *id)
 {
 	static int ds_version_printed;
-	struct mdesc_node *endp;
 	struct ldc_channel_config ds_cfg = {
 		.event		= ds_event,
 		.mtu		= 4096,
@@ -563,20 +564,11 @@ static int __devinit ds_probe(struct vio_dev *vdev,
 	};
 	struct ldc_channel *lp;
 	struct ds_info *dp;
-	const u64 *chan_id;
 	int err;
 
 	if (ds_version_printed++ == 0)
 		printk(KERN_INFO "%s", version);
 
-	endp = vio_find_endpoint(vdev);
-	if (!endp)
-		return -ENODEV;
-
-	chan_id = md_get_property(endp, "id", NULL);
-	if (!chan_id)
-		return -ENODEV;
-
 	dp = kzalloc(sizeof(*dp), GFP_KERNEL);
 	err = -ENOMEM;
 	if (!dp)
@@ -588,10 +580,10 @@ static int __devinit ds_probe(struct vio_dev *vdev,
 
 	dp->rcv_buf_len = 4096;
 
-	ds_cfg.tx_irq = endp->irqs[0];
-	ds_cfg.rx_irq = endp->irqs[1];
+	ds_cfg.tx_irq = vdev->tx_irq;
+	ds_cfg.rx_irq = vdev->rx_irq;
 
-	lp = ldc_alloc(*chan_id, &ds_cfg, dp);
+	lp = ldc_alloc(vdev->channel_id, &ds_cfg, dp);
 	if (IS_ERR(lp)) {
 		err = PTR_ERR(lp);
 		goto out_free_rcv_buf;
diff --git a/arch/sparc64/kernel/ldc.c b/arch/sparc64/kernel/ldc.c
index dbb65b674a67..85a2be0b0962 100644
--- a/arch/sparc64/kernel/ldc.c
+++ b/arch/sparc64/kernel/ldc.c
@@ -2335,15 +2335,20 @@ EXPORT_SYMBOL(ldc_free_exp_dring);
 
 static int __init ldc_init(void)
 {
-	struct mdesc_node *mp;
 	unsigned long major, minor;
+	struct mdesc_handle *hp;
 	const u64 *v;
+	u64 mp;
 
-	mp = md_find_node_by_name(NULL, "platform");
-	if (!mp)
+	hp = mdesc_grab();
+	if (!hp)
 		return -ENODEV;
 
-	v = md_get_property(mp, "domaining-enabled", NULL);
+	mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
+	if (mp == MDESC_NODE_NULL)
+		return -ENODEV;
+
+	v = mdesc_get_property(hp, mp, "domaining-enabled", NULL);
 	if (!v)
 		return -ENODEV;
 
diff --git a/arch/sparc64/kernel/mdesc.c b/arch/sparc64/kernel/mdesc.c
index f0e16045fb16..9e5088d563cc 100644
--- a/arch/sparc64/kernel/mdesc.c
+++ b/arch/sparc64/kernel/mdesc.c
@@ -6,6 +6,8 @@
 #include <linux/types.h>
 #include <linux/bootmem.h>
 #include <linux/log2.h>
+#include <linux/list.h>
+#include <linux/slab.h>
 
 #include <asm/hypervisor.h>
 #include <asm/mdesc.h>
@@ -29,7 +31,7 @@ struct mdesc_hdr {
 	u32	node_sz; /* node block size */
 	u32	name_sz; /* name block size */
 	u32	data_sz; /* data block size */
-};
+} __attribute__((aligned(16)));
 
 struct mdesc_elem {
 	u8	tag;
@@ -53,306 +55,386 @@ struct mdesc_elem {
 	} d;
 };
 
-static struct mdesc_hdr *main_mdesc;
-static struct mdesc_node *allnodes;
+struct mdesc_mem_ops {
+	struct mdesc_handle *(*alloc)(unsigned int mdesc_size);
+	void (*free)(struct mdesc_handle *handle);
+};
 
-static struct mdesc_node *allnodes_tail;
-static unsigned int unique_id;
+struct mdesc_handle {
+	struct list_head	list;
+	struct mdesc_mem_ops	*mops;
+	void			*self_base;
+	atomic_t		refcnt;
+	unsigned int		handle_size;
+	struct mdesc_hdr	mdesc;
+};
 
-static struct mdesc_node **mdesc_hash;
-static unsigned int mdesc_hash_size;
-
-static inline unsigned int node_hashfn(u64 node)
+static void mdesc_handle_init(struct mdesc_handle *hp,
+			      unsigned int handle_size,
+			      void *base)
 {
-	return ((unsigned int) (node ^ (node >> 8) ^ (node >> 16)))
-		& (mdesc_hash_size - 1);
+	BUG_ON(((unsigned long)&hp->mdesc) & (16UL - 1));
+
+	memset(hp, 0, handle_size);
+	INIT_LIST_HEAD(&hp->list);
+	hp->self_base = base;
+	atomic_set(&hp->refcnt, 1);
+	hp->handle_size = handle_size;
 }
 
-static inline void hash_node(struct mdesc_node *mp)
+static struct mdesc_handle *mdesc_bootmem_alloc(unsigned int mdesc_size)
 {
-	struct mdesc_node **head = &mdesc_hash[node_hashfn(mp->node)];
+	struct mdesc_handle *hp;
+	unsigned int handle_size, alloc_size;
 
-	mp->hash_next = *head;
-	*head = mp;
+	handle_size = (sizeof(struct mdesc_handle) -
+		       sizeof(struct mdesc_hdr) +
+		       mdesc_size);
+	alloc_size = PAGE_ALIGN(handle_size);
 
-	if (allnodes_tail) {
-		allnodes_tail->allnodes_next = mp;
-		allnodes_tail = mp;
-	} else {
-		allnodes = allnodes_tail = mp;
+	hp = __alloc_bootmem(alloc_size, PAGE_SIZE, 0UL);
+	if (hp)
+		mdesc_handle_init(hp, handle_size, hp);
+
+	return hp;
+}
+
+static void mdesc_bootmem_free(struct mdesc_handle *hp)
+{
+	unsigned int alloc_size, handle_size = hp->handle_size;
+	unsigned long start, end;
+
+	BUG_ON(atomic_read(&hp->refcnt) != 0);
+	BUG_ON(!list_empty(&hp->list));
+
+	alloc_size = PAGE_ALIGN(handle_size);
+
+	start = (unsigned long) hp;
+	end = start + alloc_size;
+
+	while (start < end) {
+		struct page *p;
+
+		p = virt_to_page(start);
+		ClearPageReserved(p);
+		__free_page(p);
+		start += PAGE_SIZE;
 	}
 }
 
-static struct mdesc_node *find_node(u64 node)
+static struct mdesc_mem_ops bootmem_mdesc_memops = {
+	.alloc = mdesc_bootmem_alloc,
+	.free  = mdesc_bootmem_free,
+};
+
+static struct mdesc_handle *mdesc_kmalloc(unsigned int mdesc_size)
 {
-	struct mdesc_node *mp = mdesc_hash[node_hashfn(node)];
+	unsigned int handle_size;
+	void *base;
 
-	while (mp) {
-		if (mp->node == node)
-			return mp;
+	handle_size = (sizeof(struct mdesc_handle) -
+		       sizeof(struct mdesc_hdr) +
+		       mdesc_size);
 
-		mp = mp->hash_next;
+	base = kmalloc(handle_size + 15, GFP_KERNEL);
+	if (base) {
+		struct mdesc_handle *hp;
+		unsigned long addr;
+
+		addr = (unsigned long)base;
+		addr = (addr + 15UL) & ~15UL;
+		hp = (struct mdesc_handle *) addr;
+
+		mdesc_handle_init(hp, handle_size, base);
+		return hp;
 	}
+
 	return NULL;
 }
 
-struct property *md_find_property(const struct mdesc_node *mp,
-				  const char *name,
-				  int *lenp)
+static void mdesc_kfree(struct mdesc_handle *hp)
 {
-	struct property *pp;
+	BUG_ON(atomic_read(&hp->refcnt) != 0);
+	BUG_ON(!list_empty(&hp->list));
 
-	for (pp = mp->properties; pp != 0; pp = pp->next) {
-		if (strcasecmp(pp->name, name) == 0) {
-			if (lenp)
-				*lenp = pp->length;
-			break;
-		}
+	kfree(hp->self_base);
+}
+
+static struct mdesc_mem_ops kmalloc_mdesc_memops = {
+	.alloc = mdesc_kmalloc,
+	.free  = mdesc_kfree,
+};
+
+static struct mdesc_handle *mdesc_alloc(unsigned int mdesc_size,
+					struct mdesc_mem_ops *mops)
+{
+	struct mdesc_handle *hp = mops->alloc(mdesc_size);
+
+	if (hp)
+		hp->mops = mops;
+
+	return hp;
+}
+
+static void mdesc_free(struct mdesc_handle *hp)
+{
+	hp->mops->free(hp);
+}
+
+static struct mdesc_handle *cur_mdesc;
+static LIST_HEAD(mdesc_zombie_list);
+static DEFINE_SPINLOCK(mdesc_lock);
+
+struct mdesc_handle *mdesc_grab(void)
+{
+	struct mdesc_handle *hp;
+	unsigned long flags;
+
+	spin_lock_irqsave(&mdesc_lock, flags);
+	hp = cur_mdesc;
+	if (hp)
+		atomic_inc(&hp->refcnt);
+	spin_unlock_irqrestore(&mdesc_lock, flags);
+
+	return hp;
+}
+EXPORT_SYMBOL(mdesc_grab);
+
+void mdesc_release(struct mdesc_handle *hp)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&mdesc_lock, flags);
+	if (atomic_dec_and_test(&hp->refcnt)) {
+		list_del_init(&hp->list);
+		hp->mops->free(hp);
 	}
-	return pp;
+	spin_unlock_irqrestore(&mdesc_lock, flags);
 }
-EXPORT_SYMBOL(md_find_property);
+EXPORT_SYMBOL(mdesc_release);
 
-/*
- * Find a property with a given name for a given node
- * and return the value.
- */
-const void *md_get_property(const struct mdesc_node *mp, const char *name,
-			    int *lenp)
+static void do_mdesc_update(struct work_struct *work)
 {
-	struct property *pp = md_find_property(mp, name, lenp);
-	return pp ? pp->value : NULL;
-}
-EXPORT_SYMBOL(md_get_property);
+	unsigned long len, real_len, status;
+	struct mdesc_handle *hp, *orig_hp;
+	unsigned long flags;
 
-struct mdesc_node *md_find_node_by_name(struct mdesc_node *from,
-					const char *name)
-{
-	struct mdesc_node *mp;
+	(void) sun4v_mach_desc(0UL, 0UL, &len);
 
-	mp = from ? from->allnodes_next : allnodes;
-	for (; mp != NULL; mp = mp->allnodes_next) {
-		if (strcmp(mp->name, name) == 0)
-			break;
-	}
-	return mp;
-}
-EXPORT_SYMBOL(md_find_node_by_name);
-
-static unsigned int mdesc_early_allocated;
-
-static void * __init mdesc_early_alloc(unsigned long size)
-{
-	void *ret;
-
-	ret = __alloc_bootmem(size, SMP_CACHE_BYTES, 0UL);
-	if (ret == NULL) {
-		prom_printf("MDESC: alloc of %lu bytes failed.\n", size);
-		prom_halt();
+	hp = mdesc_alloc(len, &kmalloc_mdesc_memops);
+	if (!hp) {
+		printk(KERN_ERR "MD: mdesc alloc fails\n");
+		return;
 	}
 
-	memset(ret, 0, size);
-
-	mdesc_early_allocated += size;
-
-	return ret;
-}
-
-static unsigned int __init count_arcs(struct mdesc_elem *ep)
-{
-	unsigned int ret = 0;
-
-	ep++;
-	while (ep->tag != MD_NODE_END) {
-		if (ep->tag == MD_PROP_ARC)
-			ret++;
-		ep++;
+	status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
+	if (status != HV_EOK || real_len > len) {
+		printk(KERN_ERR "MD: mdesc reread fails with %lu\n",
+		       status);
+		atomic_dec(&hp->refcnt);
+		mdesc_free(hp);
+		return;
 	}
-	return ret;
+
+	spin_lock_irqsave(&mdesc_lock, flags);
+	orig_hp = cur_mdesc;
+	cur_mdesc = hp;
+
+	if (atomic_dec_and_test(&orig_hp->refcnt))
+		mdesc_free(orig_hp);
+	else
+		list_add(&orig_hp->list, &mdesc_zombie_list);
+	spin_unlock_irqrestore(&mdesc_lock, flags);
 }
 
-static void __init mdesc_node_alloc(u64 node, struct mdesc_elem *ep, const char *names)
+static DECLARE_WORK(mdesc_update_work, do_mdesc_update);
+
+void mdesc_update(void)
 {
-	unsigned int num_arcs = count_arcs(ep);
-	struct mdesc_node *mp;
-
-	mp = mdesc_early_alloc(sizeof(*mp) +
-			       (num_arcs * sizeof(struct mdesc_arc)));
-	mp->name = names + ep->name_offset;
-	mp->node = node;
-	mp->unique_id = unique_id++;
-	mp->num_arcs = num_arcs;
-
-	hash_node(mp);
+	schedule_work(&mdesc_update_work);
 }
 
-static inline struct mdesc_elem *node_block(struct mdesc_hdr *mdesc)
+static struct mdesc_elem *node_block(struct mdesc_hdr *mdesc)
 {
 	return (struct mdesc_elem *) (mdesc + 1);
 }
 
-static inline void *name_block(struct mdesc_hdr *mdesc)
+static void *name_block(struct mdesc_hdr *mdesc)
 {
 	return ((void *) node_block(mdesc)) + mdesc->node_sz;
 }
 
-static inline void *data_block(struct mdesc_hdr *mdesc)
+static void *data_block(struct mdesc_hdr *mdesc)
 {
 	return ((void *) name_block(mdesc)) + mdesc->name_sz;
 }
 
-/* In order to avoid recursion (the graph can be very deep) we use a
- * two pass algorithm.  First we allocate all the nodes and hash them.
- * Then we iterate over each node, filling in the arcs and properties.
- */
-static void __init build_all_nodes(struct mdesc_hdr *mdesc)
+u64 mdesc_node_by_name(struct mdesc_handle *hp,
+		       u64 from_node, const char *name)
 {
-	struct mdesc_elem *start, *ep;
-	struct mdesc_node *mp;
-	const char *names;
-	void *data;
-	u64 last_node;
+	struct mdesc_elem *ep = node_block(&hp->mdesc);
+	const char *names = name_block(&hp->mdesc);
+	u64 last_node = hp->mdesc.node_sz / 16;
+	u64 ret;
 
-	start = ep = node_block(mdesc);
-	last_node = mdesc->node_sz / 16;
+	if (from_node == MDESC_NODE_NULL)
+		from_node = 0;
 
-	names = name_block(mdesc);
+	if (from_node >= last_node)
+		return MDESC_NODE_NULL;
 
-	while (1) {
-		u64 node = ep - start;
+	ret = ep[from_node].d.val;
+	while (ret < last_node) {
+		if (ep[ret].tag != MD_NODE)
+			return MDESC_NODE_NULL;
+		if (!strcmp(names + ep[ret].name_offset, name))
+			break;
+		ret = ep[ret].d.val;
+	}
+	if (ret >= last_node)
+		ret = MDESC_NODE_NULL;
+	return ret;
+}
+EXPORT_SYMBOL(mdesc_node_by_name);
 
-		if (ep->tag == MD_LIST_END)
+const void *mdesc_get_property(struct mdesc_handle *hp, u64 node,
+			       const char *name, int *lenp)
+{
+	const char *names = name_block(&hp->mdesc);
+	u64 last_node = hp->mdesc.node_sz / 16;
+	void *data = data_block(&hp->mdesc);
+	struct mdesc_elem *ep;
+
+	if (node == MDESC_NODE_NULL || node >= last_node)
+		return NULL;
+
+	ep = node_block(&hp->mdesc) + node;
+	ep++;
+	for (; ep->tag != MD_NODE_END; ep++) {
+		void *val = NULL;
+		int len = 0;
+
+		switch (ep->tag) {
+		case MD_PROP_VAL:
+			val = &ep->d.val;
+			len = 8;
 			break;
 
-		if (ep->tag != MD_NODE) {
-			prom_printf("MDESC: Inconsistent element list.\n");
-			prom_halt();
-		}
+		case MD_PROP_STR:
+		case MD_PROP_DATA:
+			val = data + ep->d.data.data_offset;
+			len = ep->d.data.data_len;
+			break;
 
-		mdesc_node_alloc(node, ep, names);
-
-		if (ep->d.val >= last_node) {
-			printk("MDESC: Warning, early break out of node scan.\n");
-			printk("MDESC: Next node [%lu] last_node [%lu].\n",
-			       node, last_node);
+		default:
 			break;
 		}
+		if (!val)
+			continue;
 
-		ep = start + ep->d.val;
-	}
-
-	data = data_block(mdesc);
-	for (mp = allnodes; mp; mp = mp->allnodes_next) {
-		struct mdesc_elem *ep = start + mp->node;
-		struct property **link = &mp->properties;
-		unsigned int this_arc = 0;
-
-		ep++;
-		while (ep->tag != MD_NODE_END) {
-			switch (ep->tag) {
-			case MD_PROP_ARC: {
-				struct mdesc_node *target;
-
-				if (this_arc >= mp->num_arcs) {
-					prom_printf("MDESC: ARC overrun [%u:%u]\n",
-						    this_arc, mp->num_arcs);
-					prom_halt();
-				}
-				target = find_node(ep->d.val);
-				if (!target) {
-					printk("MDESC: Warning, arc points to "
-					       "missing node, ignoring.\n");
-					break;
-				}
-				mp->arcs[this_arc].name =
-					(names + ep->name_offset);
-				mp->arcs[this_arc].arc = target;
-				this_arc++;
-				break;
-			}
-
-			case MD_PROP_VAL:
-			case MD_PROP_STR:
-			case MD_PROP_DATA: {
-				struct property *p = mdesc_early_alloc(sizeof(*p));
-
-				p->unique_id = unique_id++;
-				p->name = (char *) names + ep->name_offset;
-				if (ep->tag == MD_PROP_VAL) {
-					p->value = &ep->d.val;
-					p->length = 8;
-				} else {
-					p->value = data + ep->d.data.data_offset;
-					p->length = ep->d.data.data_len;
-				}
-				*link = p;
-				link = &p->next;
-				break;
-			}
-
-			case MD_NOOP:
-				break;
-
-			default:
-				printk("MDESC: Warning, ignoring unknown tag type %02x\n",
-				       ep->tag);
-			}
-			ep++;
+		if (!strcmp(names + ep->name_offset, name)) {
+			if (lenp)
+				*lenp = len;
+			return val;
 		}
 	}
-}
 
-static unsigned int __init count_nodes(struct mdesc_hdr *mdesc)
+	return NULL;
+}
+EXPORT_SYMBOL(mdesc_get_property);
+
+u64 mdesc_next_arc(struct mdesc_handle *hp, u64 from, const char *arc_type)
 {
-	struct mdesc_elem *ep = node_block(mdesc);
-	struct mdesc_elem *end;
-	unsigned int cnt = 0;
+	struct mdesc_elem *ep, *base = node_block(&hp->mdesc);
+	const char *names = name_block(&hp->mdesc);
+	u64 last_node = hp->mdesc.node_sz / 16;
 
-	end = ((void *)ep) + mdesc->node_sz;
-	while (ep < end) {
-		if (ep->tag == MD_NODE)
-			cnt++;
-		ep++;
+	if (from == MDESC_NODE_NULL || from >= last_node)
+		return MDESC_NODE_NULL;
+
+	ep = base + from;
+
+	ep++;
+	for (; ep->tag != MD_NODE_END; ep++) {
+		if (ep->tag != MD_PROP_ARC)
+			continue;
+
+		if (strcmp(names + ep->name_offset, arc_type))
+			continue;
+
+		return ep - base;
 	}
-	return cnt;
+
+	return MDESC_NODE_NULL;
 }
+EXPORT_SYMBOL(mdesc_next_arc);
+
+u64 mdesc_arc_target(struct mdesc_handle *hp, u64 arc)
+{
+	struct mdesc_elem *ep, *base = node_block(&hp->mdesc);
+
+	ep = base + arc;
+
+	return ep->d.val;
+}
+EXPORT_SYMBOL(mdesc_arc_target);
+
+const char *mdesc_node_name(struct mdesc_handle *hp, u64 node)
+{
+	struct mdesc_elem *ep, *base = node_block(&hp->mdesc);
+	const char *names = name_block(&hp->mdesc);
+	u64 last_node = hp->mdesc.node_sz / 16;
+
+	if (node == MDESC_NODE_NULL || node >= last_node)
+		return NULL;
+
+	ep = base + node;
+	if (ep->tag != MD_NODE)
+		return NULL;
+
+	return names + ep->name_offset;
+}
+EXPORT_SYMBOL(mdesc_node_name);
 
 static void __init report_platform_properties(void)
 {
-	struct mdesc_node *pn = md_find_node_by_name(NULL, "platform");
+	struct mdesc_handle *hp = mdesc_grab();
+	u64 pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
 	const char *s;
 	const u64 *v;
 
-	if (!pn) {
+	if (pn == MDESC_NODE_NULL) {
 		prom_printf("No platform node in machine-description.\n");
 		prom_halt();
 	}
 
-	s = md_get_property(pn, "banner-name", NULL);
+	s = mdesc_get_property(hp, pn, "banner-name", NULL);
 	printk("PLATFORM: banner-name [%s]\n", s);
-	s = md_get_property(pn, "name", NULL);
+	s = mdesc_get_property(hp, pn, "name", NULL);
 	printk("PLATFORM: name [%s]\n", s);
 
-	v = md_get_property(pn, "hostid", NULL);
+	v = mdesc_get_property(hp, pn, "hostid", NULL);
 	if (v)
 		printk("PLATFORM: hostid [%08lx]\n", *v);
-	v = md_get_property(pn, "serial#", NULL);
+	v = mdesc_get_property(hp, pn, "serial#", NULL);
 	if (v)
 		printk("PLATFORM: serial# [%08lx]\n", *v);
-	v = md_get_property(pn, "stick-frequency", NULL);
+	v = mdesc_get_property(hp, pn, "stick-frequency", NULL);
 	printk("PLATFORM: stick-frequency [%08lx]\n", *v);
-	v = md_get_property(pn, "mac-address", NULL);
+	v = mdesc_get_property(hp, pn, "mac-address", NULL);
 	if (v)
 		printk("PLATFORM: mac-address [%lx]\n", *v);
-	v = md_get_property(pn, "watchdog-resolution", NULL);
+	v = mdesc_get_property(hp, pn, "watchdog-resolution", NULL);
 	if (v)
 		printk("PLATFORM: watchdog-resolution [%lu ms]\n", *v);
-	v = md_get_property(pn, "watchdog-max-timeout", NULL);
+	v = mdesc_get_property(hp, pn, "watchdog-max-timeout", NULL);
 	if (v)
 		printk("PLATFORM: watchdog-max-timeout [%lu ms]\n", *v);
-	v = md_get_property(pn, "max-cpus", NULL);
+	v = mdesc_get_property(hp, pn, "max-cpus", NULL);
 	if (v)
 		printk("PLATFORM: max-cpus [%lu]\n", *v);
+
+	mdesc_release(hp);
 }
 
 static int inline find_in_proplist(const char *list, const char *match, int len)
@@ -369,15 +451,17 @@ static int inline find_in_proplist(const char *list, const char *match, int len)
 	return 0;
 }
 
-static void __init fill_in_one_cache(cpuinfo_sparc *c, struct mdesc_node *mp)
+static void __init fill_in_one_cache(cpuinfo_sparc *c,
+				     struct mdesc_handle *hp,
+				     u64 mp)
 {
-	const u64 *level = md_get_property(mp, "level", NULL);
-	const u64 *size = md_get_property(mp, "size", NULL);
-	const u64 *line_size = md_get_property(mp, "line-size", NULL);
+	const u64 *level = mdesc_get_property(hp, mp, "level", NULL);
+	const u64 *size = mdesc_get_property(hp, mp, "size", NULL);
+	const u64 *line_size = mdesc_get_property(hp, mp, "line-size", NULL);
 	const char *type;
 	int type_len;
 
-	type = md_get_property(mp, "type", &type_len);
+	type = mdesc_get_property(hp, mp, "type", &type_len);
 
 	switch (*level) {
 	case 1:
@@ -400,48 +484,44 @@ static void __init fill_in_one_cache(cpuinfo_sparc *c, struct mdesc_node *mp)
 	}
 
 	if (*level == 1) {
-		unsigned int i;
+		u64 a;
 
-		for (i = 0; i < mp->num_arcs; i++) {
-			struct mdesc_node *t = mp->arcs[i].arc;
+		mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
+			u64 target = mdesc_arc_target(hp, a);
+			const char *name = mdesc_node_name(hp, target);
 
-			if (strcmp(mp->arcs[i].name, "fwd"))
-				continue;
-
-			if (!strcmp(t->name, "cache"))
-				fill_in_one_cache(c, t);
+			if (!strcmp(name, "cache"))
+				fill_in_one_cache(c, hp, target);
 		}
 	}
 }
 
-static void __init mark_core_ids(struct mdesc_node *mp, int core_id)
+static void __init mark_core_ids(struct mdesc_handle *hp, u64 mp, int core_id)
 {
-	unsigned int i;
+	u64 a;
 
-	for (i = 0; i < mp->num_arcs; i++) {
-		struct mdesc_node *t = mp->arcs[i].arc;
+	mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_BACK) {
+		u64 t = mdesc_arc_target(hp, a);
+		const char *name;
 		const u64 *id;
 
-		if (strcmp(mp->arcs[i].name, "back"))
-			continue;
-
-		if (!strcmp(t->name, "cpu")) {
-			id = md_get_property(t, "id", NULL);
+		name = mdesc_node_name(hp, t);
+		if (!strcmp(name, "cpu")) {
+			id = mdesc_get_property(hp, t, "id", NULL);
 			if (*id < NR_CPUS)
 				cpu_data(*id).core_id = core_id;
 		} else {
-			unsigned int j;
+			u64 j;
 
-			for (j = 0; j < t->num_arcs; j++) {
-				struct mdesc_node *n = t->arcs[j].arc;
+			mdesc_for_each_arc(j, hp, t, MDESC_ARC_TYPE_BACK) {
+				u64 n = mdesc_arc_target(hp, j);
+				const char *n_name;
 
-				if (strcmp(t->arcs[j].name, "back"))
+				n_name = mdesc_node_name(hp, n);
+				if (strcmp(n_name, "cpu"))
 					continue;
 
-				if (strcmp(n->name, "cpu"))
-					continue;
-
-				id = md_get_property(n, "id", NULL);
+				id = mdesc_get_property(hp, n, "id", NULL);
 				if (*id < NR_CPUS)
 					cpu_data(*id).core_id = core_id;
 			}
@@ -449,75 +529,76 @@ static void __init mark_core_ids(struct mdesc_node *mp, int core_id)
 	}
 }
 
-static void __init set_core_ids(void)
+static void __init set_core_ids(struct mdesc_handle *hp)
 {
-	struct mdesc_node *mp;
 	int idx;
+	u64 mp;
 
 	idx = 1;
-	md_for_each_node_by_name(mp, "cache") {
-		const u64 *level = md_get_property(mp, "level", NULL);
+	mdesc_for_each_node_by_name(hp, mp, "cache") {
+		const u64 *level;
 		const char *type;
 		int len;
 
+		level = mdesc_get_property(hp, mp, "level", NULL);
 		if (*level != 1)
 			continue;
 
-		type = md_get_property(mp, "type", &len);
+		type = mdesc_get_property(hp, mp, "type", &len);
 		if (!find_in_proplist(type, "instn", len))
 			continue;
 
-		mark_core_ids(mp, idx);
+		mark_core_ids(hp, mp, idx);
 
 		idx++;
 	}
 }
 
-static void __init mark_proc_ids(struct mdesc_node *mp, int proc_id)
+static void __init mark_proc_ids(struct mdesc_handle *hp, u64 mp, int proc_id)
 {
-	int i;
+	u64 a;
 
-	for (i = 0; i < mp->num_arcs; i++) {
-		struct mdesc_node *t = mp->arcs[i].arc;
+	mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_BACK) {
+		u64 t = mdesc_arc_target(hp, a);
+		const char *name;
 		const u64 *id;
 
-		if (strcmp(mp->arcs[i].name, "back"))
+		name = mdesc_node_name(hp, t);
+		if (strcmp(name, "cpu"))
 			continue;
 
-		if (strcmp(t->name, "cpu"))
-			continue;
-
-		id = md_get_property(t, "id", NULL);
+		id = mdesc_get_property(hp, t, "id", NULL);
 		if (*id < NR_CPUS)
 			cpu_data(*id).proc_id = proc_id;
 	}
 }
 
-static void __init __set_proc_ids(const char *exec_unit_name)
+static void __init __set_proc_ids(struct mdesc_handle *hp,
+				  const char *exec_unit_name)
 {
-	struct mdesc_node *mp;
 	int idx;
+	u64 mp;
 
 	idx = 0;
-	md_for_each_node_by_name(mp, exec_unit_name) {
+	mdesc_for_each_node_by_name(hp, mp, exec_unit_name) {
 		const char *type;
 		int len;
 
-		type = md_get_property(mp, "type", &len);
+		type = mdesc_get_property(hp, mp, "type", &len);
 		if (!find_in_proplist(type, "int", len) &&
 		    !find_in_proplist(type, "integer", len))
 			continue;
 
-		mark_proc_ids(mp, idx);
+		mark_proc_ids(hp, mp, idx);
 
 		idx++;
 	}
 }
 
-static void __init set_proc_ids(void)
+static void __init set_proc_ids(struct mdesc_handle *hp)
 {
-	__set_proc_ids("exec_unit");
-	__set_proc_ids("exec-unit");
+	__set_proc_ids(hp, "exec_unit");
+	__set_proc_ids(hp, "exec-unit");
 }
 
 static void __init get_one_mondo_bits(const u64 *p, unsigned int *mask, unsigned char def)
@@ -538,35 +619,37 @@ use_default:
 	*mask = ((1U << def) * 64U) - 1U;
 }
 
-static void __init get_mondo_data(struct mdesc_node *mp, struct trap_per_cpu *tb)
+static void __init get_mondo_data(struct mdesc_handle *hp, u64 mp,
+				  struct trap_per_cpu *tb)
 {
 	const u64 *val;
 
-	val = md_get_property(mp, "q-cpu-mondo-#bits", NULL);
+	val = mdesc_get_property(hp, mp, "q-cpu-mondo-#bits", NULL);
 	get_one_mondo_bits(val, &tb->cpu_mondo_qmask, 7);
 
-	val = md_get_property(mp, "q-dev-mondo-#bits", NULL);
+	val = mdesc_get_property(hp, mp, "q-dev-mondo-#bits", NULL);
 	get_one_mondo_bits(val, &tb->dev_mondo_qmask, 7);
 
-	val = md_get_property(mp, "q-resumable-#bits", NULL);
+	val = mdesc_get_property(hp, mp, "q-resumable-#bits", NULL);
 	get_one_mondo_bits(val, &tb->resum_qmask, 6);
 
-	val = md_get_property(mp, "q-nonresumable-#bits", NULL);
+	val = mdesc_get_property(hp, mp, "q-nonresumable-#bits", NULL);
 	get_one_mondo_bits(val, &tb->nonresum_qmask, 2);
 }
 
 static void __init mdesc_fill_in_cpu_data(void)
 {
-	struct mdesc_node *mp;
+	struct mdesc_handle *hp = mdesc_grab();
+	u64 mp;
 
 	ncpus_probed = 0;
-	md_for_each_node_by_name(mp, "cpu") {
-		const u64 *id = md_get_property(mp, "id", NULL);
-		const u64 *cfreq = md_get_property(mp, "clock-frequency", NULL);
+	mdesc_for_each_node_by_name(hp, mp, "cpu") {
+		const u64 *id = mdesc_get_property(hp, mp, "id", NULL);
+		const u64 *cfreq = mdesc_get_property(hp, mp, "clock-frequency", NULL);
 		struct trap_per_cpu *tb;
 		cpuinfo_sparc *c;
-		unsigned int i;
 		int cpuid;
+		u64 a;
 
 		ncpus_probed++;
 
@@ -589,29 +672,25 @@ static void __init mdesc_fill_in_cpu_data(void)
 		c->clock_tick = *cfreq;
 
 		tb = &trap_block[cpuid];
-		get_mondo_data(mp, tb);
+		get_mondo_data(hp, mp, tb);
 
-		for (i = 0; i < mp->num_arcs; i++) {
-			struct mdesc_node *t = mp->arcs[i].arc;
-			unsigned int j;
+		mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
+			u64 j, t = mdesc_arc_target(hp, a);
+			const char *t_name;
 
-			if (strcmp(mp->arcs[i].name, "fwd"))
-				continue;
-
-			if (!strcmp(t->name, "cache")) {
-				fill_in_one_cache(c, t);
+			t_name = mdesc_node_name(hp, t);
+			if (!strcmp(t_name, "cache")) {
+				fill_in_one_cache(c, hp, t);
 				continue;
 			}
 
-			for (j = 0; j < t->num_arcs; j++) {
-				struct mdesc_node *n;
+			mdesc_for_each_arc(j, hp, t, MDESC_ARC_TYPE_FWD) {
+				u64 n = mdesc_arc_target(hp, j);
+				const char *n_name;
 
-				n = t->arcs[j].arc;
-				if (strcmp(t->arcs[j].name, "fwd"))
-					continue;
-
-				if (!strcmp(n->name, "cache"))
-					fill_in_one_cache(c, n);
+				n_name = mdesc_node_name(hp, n);
+				if (!strcmp(n_name, "cache"))
+					fill_in_one_cache(c, hp, n);
 			}
 		}
 
@@ -628,44 +707,39 @@ static void __init mdesc_fill_in_cpu_data(void)
 	sparc64_multi_core = 1;
 #endif
 
-	set_core_ids();
-	set_proc_ids();
+	set_core_ids(hp);
+	set_proc_ids(hp);
 
 	smp_fill_in_sib_core_maps();
+
+	mdesc_release(hp);
 }
 
 void __init sun4v_mdesc_init(void)
 {
+	struct mdesc_handle *hp;
 	unsigned long len, real_len, status;
 
 	(void) sun4v_mach_desc(0UL, 0UL, &len);
 
 	printk("MDESC: Size is %lu bytes.\n", len);
 
-	main_mdesc = mdesc_early_alloc(len);
+	hp = mdesc_alloc(len, &bootmem_mdesc_memops);
+	if (hp == NULL) {
+		prom_printf("MDESC: alloc of %lu bytes failed.\n", len);
+		prom_halt();
+	}
 
-	status = sun4v_mach_desc(__pa(main_mdesc), len, &real_len);
+	status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
 	if (status != HV_EOK || real_len > len) {
 		prom_printf("sun4v_mach_desc fails, err(%lu), "
 			    "len(%lu), real_len(%lu)\n",
 			    status, len, real_len);
+		mdesc_free(hp);
 		prom_halt();
 	}
 
-	len = count_nodes(main_mdesc);
-	printk("MDESC: %lu nodes.\n", len);
-
-	len = roundup_pow_of_two(len);
-
-	mdesc_hash = mdesc_early_alloc(len * sizeof(struct mdesc_node *));
-	mdesc_hash_size = len;
-
-	printk("MDESC: Hash size %lu entries.\n", len);
-
-	build_all_nodes(main_mdesc);
-
-	printk("MDESC: Built graph with %u bytes of memory.\n",
-	       mdesc_early_allocated);
+	cur_mdesc = hp;
 
 	report_platform_properties();
 	mdesc_fill_in_cpu_data();
diff --git a/arch/sparc64/kernel/vio.c b/arch/sparc64/kernel/vio.c
index 7eccc91cd59d..64f082555bcd 100644
--- a/arch/sparc64/kernel/vio.c
+++ b/arch/sparc64/kernel/vio.c
@@ -147,30 +147,6 @@ void vio_unregister_driver(struct vio_driver *viodrv)
 }
 EXPORT_SYMBOL(vio_unregister_driver);
 
-struct mdesc_node *vio_find_endpoint(struct vio_dev *vdev)
-{
-	struct mdesc_node *endp, *mp = vdev->mp;
-	int i;
-
-	endp = NULL;
-	for (i = 0; i < mp->num_arcs; i++) {
-		struct mdesc_node *t;
-
-		if (strcmp(mp->arcs[i].name, "fwd"))
-			continue;
-
-		t = mp->arcs[i].arc;
-		if (strcmp(t->name, "channel-endpoint"))
-			continue;
-
-		endp = t;
-		break;
-	}
-
-	return endp;
-}
-EXPORT_SYMBOL(vio_find_endpoint);
-
 static void __devinit vio_dev_release(struct device *dev)
 {
 	kfree(to_vio_dev(dev));
@@ -197,22 +173,47 @@ struct device_node *cdev_node;
 static struct vio_dev *root_vdev;
 static u64 cdev_cfg_handle;
 
-static struct vio_dev *vio_create_one(struct mdesc_node *mp,
+static void vio_fill_channel_info(struct mdesc_handle *hp, u64 mp,
+				  struct vio_dev *vdev)
+{
+	u64 a;
+
+	mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
+		const u64 *chan_id;
+		const u64 *irq;
+		u64 target;
+
+		target = mdesc_arc_target(hp, a);
+
+		irq = mdesc_get_property(hp, target, "tx-ino", NULL);
+		if (irq)
+			vdev->tx_irq = sun4v_build_virq(cdev_cfg_handle, *irq);
+
+		irq = mdesc_get_property(hp, target, "rx-ino", NULL);
+		if (irq)
+			vdev->rx_irq = sun4v_build_virq(cdev_cfg_handle, *irq);
+
+		chan_id = mdesc_get_property(hp, target, "id", NULL);
+		if (chan_id)
+			vdev->channel_id = *chan_id;
+	}
+}
+
+static struct vio_dev *vio_create_one(struct mdesc_handle *hp, u64 mp,
 				      struct device *parent)
 {
 	const char *type, *compat;
 	struct device_node *dp;
 	struct vio_dev *vdev;
-	const u64 *irq;
 	int err, clen;
 
-	type = md_get_property(mp, "device-type", NULL);
+	type = mdesc_get_property(hp, mp, "device-type", NULL);
 	if (!type) {
-		type = md_get_property(mp, "name", NULL);
+		type = mdesc_get_property(hp, mp, "name", NULL);
 		if (!type)
-			type = mp->name;
+			type = mdesc_node_name(hp, mp);
 	}
-	compat = md_get_property(mp, "device-type", &clen);
+	compat = mdesc_get_property(hp, mp, "device-type", &clen);
 
 	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 	if (!vdev) {
@@ -225,15 +226,13 @@ static struct vio_dev *vio_create_one(struct mdesc_node *mp,
 	vdev->compat = compat;
 	vdev->compat_len = clen;
 
-	irq = md_get_property(mp, "tx-ino", NULL);
-	if (irq)
-		mp->irqs[0] = sun4v_build_virq(cdev_cfg_handle, *irq);
+	vdev->channel_id = ~0UL;
+	vdev->tx_irq = ~0;
+	vdev->rx_irq = ~0;
 
-	irq = md_get_property(mp, "rx-ino", NULL);
-	if (irq)
-		mp->irqs[1] = sun4v_build_virq(cdev_cfg_handle, *irq);
+	vio_fill_channel_info(hp, mp, vdev);
 
-	snprintf(vdev->dev.bus_id, BUS_ID_SIZE, "%lx", mp->node);
+	snprintf(vdev->dev.bus_id, BUS_ID_SIZE, "%lx", mp);
 	vdev->dev.parent = parent;
 	vdev->dev.bus = &vio_bus_type;
 	vdev->dev.release = vio_dev_release;
@@ -267,46 +266,43 @@ static struct vio_dev *vio_create_one(struct mdesc_node *mp,
 	return vdev;
 }
 
-static void walk_tree(struct mdesc_node *n, struct vio_dev *parent)
+static void walk_tree(struct mdesc_handle *hp, u64 n, struct vio_dev *parent)
 {
-	int i;
+	u64 a;
 
-	for (i = 0; i < n->num_arcs; i++) {
-		struct mdesc_node *mp;
+	mdesc_for_each_arc(a, hp, n, MDESC_ARC_TYPE_FWD) {
 		struct vio_dev *vdev;
+		u64 target;
 
-		if (strcmp(n->arcs[i].name, "fwd"))
-			continue;
-
-		mp = n->arcs[i].arc;
-
-		vdev = vio_create_one(mp, &parent->dev);
-		if (vdev && mp->num_arcs)
-			walk_tree(mp, vdev);
+		target = mdesc_arc_target(hp, a);
+		vdev = vio_create_one(hp, target, &parent->dev);
+		if (vdev)
+			walk_tree(hp, target, vdev);
 	}
 }
 
-static void create_devices(struct mdesc_node *root)
+static void create_devices(struct mdesc_handle *hp, u64 root)
 {
-	struct mdesc_node *mp;
+	u64 mp;
 
-	root_vdev = vio_create_one(root, NULL);
+	root_vdev = vio_create_one(hp, root, NULL);
 	if (!root_vdev) {
 		printk(KERN_ERR "VIO: Coult not create root device.\n");
 		return;
 	}
 
-	walk_tree(root, root_vdev);
+	walk_tree(hp, root, root_vdev);
 
 	/* Domain services is odd as it doesn't sit underneath the
 	 * channel-devices node, so we plug it in manually.
 	 */
-	mp = md_find_node_by_name(NULL, "domain-services");
-	if (mp) {
-		struct vio_dev *parent = vio_create_one(mp, &root_vdev->dev);
+	mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "domain-services");
+	if (mp != MDESC_NODE_NULL) {
+		struct vio_dev *parent = vio_create_one(hp, mp,
+							&root_vdev->dev);
 
 		if (parent)
-			walk_tree(mp, parent);
+			walk_tree(hp, mp, parent);
 	}
 }
 
@@ -316,40 +312,47 @@ const char *cfg_handle_prop = "cfg-handle";
 
 static int __init vio_init(void)
 {
-	struct mdesc_node *root;
+	struct mdesc_handle *hp;
 	const char *compat;
 	const u64 *cfg_handle;
 	int err, len;
+	u64 root;
 
-	root = md_find_node_by_name(NULL, channel_devices_node);
-	if (!root) {
+	hp = mdesc_grab();
+	if (!hp)
+		return 0;
+
+	root = mdesc_node_by_name(hp, MDESC_NODE_NULL, channel_devices_node);
+	if (root == MDESC_NODE_NULL) {
 		printk(KERN_INFO "VIO: No channel-devices MDESC node.\n");
+		mdesc_release(hp);
 		return 0;
 	}
 
 	cdev_node = of_find_node_by_name(NULL, "channel-devices");
+	err = -ENODEV;
 	if (!cdev_node) {
 		printk(KERN_INFO "VIO: No channel-devices OBP node.\n");
-		return -ENODEV;
+		goto out_release;
 	}
 
-	compat = md_get_property(root, "compatible", &len);
+	compat = mdesc_get_property(hp, root, "compatible", &len);
 	if (!compat) {
 		printk(KERN_ERR "VIO: Channel devices lacks compatible "
 		       "property\n");
-		return -ENODEV;
+		goto out_release;
 	}
 	if (!find_in_proplist(compat, channel_devices_compat, len)) {
 		printk(KERN_ERR "VIO: Channel devices node lacks (%s) "
 		       "compat entry.\n", channel_devices_compat);
-		return -ENODEV;
+		goto out_release;
 	}
 
-	cfg_handle = md_get_property(root, cfg_handle_prop, NULL);
+	cfg_handle = mdesc_get_property(hp, root, cfg_handle_prop, NULL);
 	if (!cfg_handle) {
 		printk(KERN_ERR "VIO: Channel devices lacks %s property\n",
 		       cfg_handle_prop);
-		return -ENODEV;
+		goto out_release;
 	}
 
 	cdev_cfg_handle = *cfg_handle;
@@ -361,9 +364,15 @@ static int __init vio_init(void)
 		return err;
 	}
 
-	create_devices(root);
+	create_devices(hp, root);
+
+	mdesc_release(hp);
 
 	return 0;
+
+out_release:
+	mdesc_release(hp);
+	return err;
 }
 
 postcore_initcall(vio_init);
diff --git a/arch/sparc64/kernel/viohs.c b/arch/sparc64/kernel/viohs.c
index b0b1b8779342..15613add45d1 100644
--- a/arch/sparc64/kernel/viohs.c
+++ b/arch/sparc64/kernel/viohs.c
@@ -136,7 +136,7 @@ static int process_unknown(struct vio_driver_state *vio, void *arg)
 	       pkt->type, pkt->stype, pkt->stype_env, pkt->sid);
 
 	printk(KERN_ERR "vio: ID[%lu] Resetting connection.\n",
-	       vio->channel_id);
+	       vio->vdev->channel_id);
 
 	ldc_disconnect(vio->lp);
 
@@ -678,21 +678,11 @@ extern int vio_ldc_alloc(struct vio_driver_state *vio,
 {
 	struct ldc_channel_config cfg = *base_cfg;
 	struct ldc_channel *lp;
-	const u64 *id;
 
-	id = md_get_property(vio->endpoint, "id", NULL);
-	if (!id) {
-		printk(KERN_ERR "%s: Channel lacks id property.\n",
-		       vio->name);
-		return -ENODEV;
-	}
+	cfg.tx_irq = vio->vdev->tx_irq;
+	cfg.rx_irq = vio->vdev->rx_irq;
 
-	vio->channel_id = *id;
-
-	cfg.rx_irq = vio->rx_irq;
-	cfg.tx_irq = vio->tx_irq;
-
-	lp = ldc_alloc(vio->channel_id, &cfg, event_arg);
+	lp = ldc_alloc(vio->vdev->channel_id, &cfg, event_arg);
 	if (IS_ERR(lp))
 		return PTR_ERR(lp);
 
@@ -728,7 +718,7 @@ void vio_port_up(struct vio_driver_state *vio)
 		if (err)
 			printk(KERN_WARNING "%s: Port %lu bind failed, "
 			       "err=%d\n",
-			       vio->name, vio->channel_id, err);
+			       vio->name, vio->vdev->channel_id, err);
 	}
 
 	if (!err) {
@@ -736,7 +726,7 @@ void vio_port_up(struct vio_driver_state *vio)
 		if (err)
 			printk(KERN_WARNING "%s: Port %lu connect failed, "
 			       "err=%d\n",
-			       vio->name, vio->channel_id, err);
+			       vio->name, vio->vdev->channel_id, err);
 	}
 	if (err) {
 		unsigned long expires = jiffies + HZ;
@@ -757,9 +747,9 @@ static void vio_port_timer(unsigned long _arg)
 }
 
 int vio_driver_init(struct vio_driver_state *vio, struct vio_dev *vdev,
-		    u8 dev_class, struct mdesc_node *channel_endpoint,
-		    struct vio_version *ver_table, int ver_table_size,
-		    struct vio_driver_ops *ops, char *name)
+		    u8 dev_class, struct vio_version *ver_table,
+		    int ver_table_size, struct vio_driver_ops *ops,
+		    char *name)
 {
 	switch (dev_class) {
 	case VDEV_NETWORK:
@@ -777,9 +767,6 @@ int vio_driver_init(struct vio_driver_state *vio, struct vio_dev *vdev,
 	    !ops->handshake_complete)
 		return -EINVAL;
 
-	if (!channel_endpoint)
-		return -EINVAL;
-
 	if (!ver_table || ver_table_size < 0)
 		return -EINVAL;
 
@@ -793,10 +780,6 @@ int vio_driver_init(struct vio_driver_state *vio, struct vio_dev *vdev,
 	vio->dev_class = dev_class;
 	vio->vdev = vdev;
 
-	vio->endpoint = channel_endpoint;
-	vio->tx_irq = channel_endpoint->irqs[0];
-	vio->rx_irq = channel_endpoint->irqs[1];
-
 	vio->ver_table = ver_table;
 	vio->ver_table_entries = ver_table_size;
 
diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index 8dbbeace52a1..0f5e3caf85d7 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -750,7 +750,7 @@ static struct vio_driver_ops vdc_vio_ops = {
 static int __devinit vdc_port_probe(struct vio_dev *vdev,
 				    const struct vio_device_id *id)
 {
-	struct mdesc_node *endp;
+	struct mdesc_handle *hp;
 	struct vdc_port *port;
 	unsigned long flags;
 	struct vdc *vp;
@@ -763,26 +763,24 @@ static int __devinit vdc_port_probe(struct vio_dev *vdev,
 		return -ENODEV;
 	}
 
-	endp = vio_find_endpoint(vdev);
-	if (!endp) {
-		printk(KERN_ERR PFX "Port lacks channel-endpoint.\n");
-		return -ENODEV;
-	}
+	hp = mdesc_grab();
 
-	port_id = md_get_property(vdev->mp, "id", NULL);
+	port_id = mdesc_get_property(hp, vdev->mp, "id", NULL);
+	err = -ENODEV;
 	if (!port_id) {
 		printk(KERN_ERR PFX "Port lacks id property.\n");
-		return -ENODEV;
+		goto err_out_release_mdesc;
 	}
 	if ((*port_id << PARTITION_SHIFT) & ~(u64)MINORMASK) {
 		printk(KERN_ERR PFX "Port id [%lu] too large.\n", *port_id);
-		return -ENODEV;
+		goto err_out_release_mdesc;
 	}
 
 	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	err = -ENOMEM;
 	if (!port) {
 		printk(KERN_ERR PFX "Cannot allocate vdc_port.\n");
-		return -ENOMEM;
+		goto err_out_release_mdesc;
 	}
 
 	port->vp = vp;
@@ -797,7 +795,7 @@ static int __devinit vdc_port_probe(struct vio_dev *vdev,
 		snprintf(port->disk_name, sizeof(port->disk_name),
 			 VDCBLK_NAME "%c", 'a' + (port->dev_no % 26));
 
-	err = vio_driver_init(&port->vio, vdev, VDEV_DISK, endp,
+	err = vio_driver_init(&port->vio, vdev, VDEV_DISK,
 			      vdc_versions, ARRAY_SIZE(vdc_versions),
 			      &vdc_vio_ops, port->disk_name);
 	if (err)
@@ -828,6 +826,8 @@ static int __devinit vdc_port_probe(struct vio_dev *vdev,
 
 	dev_set_drvdata(&vdev->dev, port);
 
+	mdesc_release(hp);
+
 	return 0;
 
 err_out_free_tx_ring:
@@ -839,6 +839,8 @@ err_out_free_ldc:
 err_out_free_port:
 	kfree(port);
 
+err_out_release_mdesc:
+	mdesc_release(hp);
 	return err;
 }
 
diff --git a/drivers/net/sunvnet.c b/drivers/net/sunvnet.c
index d764e4ccba56..8a667c13faef 100644
--- a/drivers/net/sunvnet.c
+++ b/drivers/net/sunvnet.c
@@ -892,7 +892,7 @@ const char *remote_macaddr_prop = "remote-mac-address";
 static int __devinit vnet_port_probe(struct vio_dev *vdev,
 				     const struct vio_device_id *id)
 {
-	struct mdesc_node *endp;
+	struct mdesc_handle *hp;
 	struct vnet_port *port;
 	unsigned long flags;
 	struct vnet *vp;
@@ -905,23 +905,21 @@ static int __devinit vnet_port_probe(struct vio_dev *vdev,
 		return -ENODEV;
 	}
 
-	rmac = md_get_property(vdev->mp, remote_macaddr_prop, &len);
+	hp = mdesc_grab();
+
+	rmac = mdesc_get_property(hp, vdev->mp, remote_macaddr_prop, &len);
+	err = -ENODEV;
 	if (!rmac) {
 		printk(KERN_ERR PFX "Port lacks %s property.\n",
 		       remote_macaddr_prop);
-		return -ENODEV;
-	}
-
-	endp = vio_find_endpoint(vdev);
-	if (!endp) {
-		printk(KERN_ERR PFX "Port lacks channel-endpoint.\n");
-		return -ENODEV;
+		goto err_out_put_mdesc;
 	}
 
 	port = kzalloc(sizeof(*port), GFP_KERNEL);
+	err = -ENOMEM;
 	if (!port) {
 		printk(KERN_ERR PFX "Cannot allocate vnet_port.\n");
-		return -ENOMEM;
+		goto err_out_put_mdesc;
 	}
 
 	for (i = 0; i < ETH_ALEN; i++)
@@ -929,7 +927,7 @@ static int __devinit vnet_port_probe(struct vio_dev *vdev,
 
 	port->vp = vp;
 
-	err = vio_driver_init(&port->vio, vdev, VDEV_NETWORK, endp,
+	err = vio_driver_init(&port->vio, vdev, VDEV_NETWORK,
 			      vnet_versions, ARRAY_SIZE(vnet_versions),
 			      &vnet_vio_ops, vp->dev->name);
 	if (err)
@@ -947,7 +945,7 @@ static int __devinit vnet_port_probe(struct vio_dev *vdev,
 	INIT_LIST_HEAD(&port->list);
 
 	switch_port = 0;
-	if (md_get_property(vdev->mp, "switch-port", NULL) != NULL)
+	if (mdesc_get_property(hp, vdev->mp, "switch-port", NULL) != NULL)
 		switch_port = 1;
 
 	spin_lock_irqsave(&vp->lock, flags);
@@ -969,6 +967,8 @@ static int __devinit vnet_port_probe(struct vio_dev *vdev,
 
 	vio_port_up(&port->vio);
 
+	mdesc_release(hp);
+
 	return 0;
 
 err_out_free_ldc:
@@ -977,6 +977,8 @@ err_out_free_ldc:
 err_out_free_port:
 	kfree(port);
 
+err_out_put_mdesc:
+	mdesc_release(hp);
 	return err;
 }
 
@@ -1029,6 +1031,7 @@ static int __devinit vnet_probe(struct vio_dev *vdev,
 				const struct vio_device_id *id)
 {
 	static int vnet_version_printed;
+	struct mdesc_handle *hp;
 	struct net_device *dev;
 	struct vnet *vp;
 	const u64 *mac;
@@ -1037,7 +1040,9 @@ static int __devinit vnet_probe(struct vio_dev *vdev,
 	if (vnet_version_printed++ == 0)
 		printk(KERN_INFO "%s", version);
 
-	mac = md_get_property(vdev->mp, local_mac_prop, &len);
+	hp = mdesc_grab();
+
+	mac = mdesc_get_property(hp, vdev->mp, local_mac_prop, &len);
 	if (!mac) {
 		printk(KERN_ERR PFX "vnet lacks %s property.\n",
 		       local_mac_prop);
@@ -1093,12 +1098,15 @@ static int __devinit vnet_probe(struct vio_dev *vdev,
 
 	dev_set_drvdata(&vdev->dev, vp);
 
+	mdesc_release(hp);
+
 	return 0;
 
 err_out_free_dev:
 	free_netdev(dev);
 
 err_out:
+	mdesc_release(hp);
 	return err;
 }
 
diff --git a/include/asm-sparc64/mdesc.h b/include/asm-sparc64/mdesc.h
index c6383982b53d..bbb0c0bed486 100644
--- a/include/asm-sparc64/mdesc.h
+++ b/include/asm-sparc64/mdesc.h
@@ -4,36 +4,43 @@
 #include <linux/types.h>
 #include <asm/prom.h>
 
-struct mdesc_node;
-struct mdesc_arc {
-	const char		*name;
-	struct mdesc_node	*arc;
-};
+struct mdesc_handle;
 
-struct mdesc_node {
-	const char		*name;
-	u64			node;
-	unsigned int		unique_id;
-	unsigned int		num_arcs;
-	unsigned int		irqs[2];
-	struct property		*properties;
-	struct mdesc_node	*hash_next;
-	struct mdesc_node	*allnodes_next;
-	struct mdesc_arc	arcs[0];
-};
+/* Machine description operations are to be surrounded by grab and
+ * release calls.  The mdesc_handle returned from the grab is
+ * the first argument to all of the operational calls that work
+ * on mdescs.
+ */
+extern struct mdesc_handle *mdesc_grab(void);
+extern void mdesc_release(struct mdesc_handle *);
 
-extern struct mdesc_node *md_find_node_by_name(struct mdesc_node *from,
-					       const char *name);
-#define md_for_each_node_by_name(__mn, __name) \
-	for (__mn = md_find_node_by_name(NULL, __name); __mn; \
-	     __mn = md_find_node_by_name(__mn, __name))
+#define MDESC_NODE_NULL		(~(u64)0)
 
-extern struct property *md_find_property(const struct mdesc_node *mp,
-					 const char *name,
-					 int *lenp);
-extern const void *md_get_property(const struct mdesc_node *mp,
-				   const char *name,
-				   int *lenp);
+extern u64 mdesc_node_by_name(struct mdesc_handle *handle,
+			      u64 from_node, const char *name);
+#define mdesc_for_each_node_by_name(__hdl, __node, __name) \
+	for (__node = mdesc_node_by_name(__hdl, MDESC_NODE_NULL, __name); \
+	     (__node) != MDESC_NODE_NULL; \
+	     __node = mdesc_node_by_name(__hdl, __node, __name))
+
+extern const void *mdesc_get_property(struct mdesc_handle *handle,
+				      u64 node, const char *name, int *lenp);
+
+#define MDESC_ARC_TYPE_FWD	"fwd"
+#define MDESC_ARC_TYPE_BACK	"back"
+
+extern u64 mdesc_next_arc(struct mdesc_handle *handle, u64 from,
+			  const char *arc_type);
+#define mdesc_for_each_arc(__arc, __hdl, __node, __type) \
+	for (__arc = mdesc_next_arc(__hdl, __node, __type); \
+	     (__arc) != MDESC_NODE_NULL; \
+	     __arc = mdesc_next_arc(__hdl, __arc, __type))
+
+extern u64 mdesc_arc_target(struct mdesc_handle *hp, u64 arc);
+
+extern const char *mdesc_node_name(struct mdesc_handle *hp, u64 node);
+
+extern void mdesc_update(void);
 
 extern void sun4v_mdesc_init(void);
 
diff --git a/include/asm-sparc64/vio.h b/include/asm-sparc64/vio.h
index 47c3da76dcb8..a8a53e6fc250 100644
--- a/include/asm-sparc64/vio.h
+++ b/include/asm-sparc64/vio.h
@@ -265,13 +265,18 @@ static inline u32 vio_dring_avail(struct vio_dring_state *dr,
 }
 
 struct vio_dev {
-	struct mdesc_node	*mp;
+	u64			mp;
 	struct device_node	*dp;
 
 	const char		*type;
 	const char		*compat;
 	int			compat_len;
 
+	unsigned long		channel_id;
+
+	unsigned int		tx_irq;
+	unsigned int		rx_irq;
+
 	struct device		dev;
 };
 
@@ -345,16 +350,10 @@ struct vio_driver_state {
 
 	struct vio_dev		*vdev;
 
-	unsigned long		channel_id;
-	unsigned int		tx_irq;
-	unsigned int		rx_irq;
-
 	struct timer_list	timer;
 
 	struct vio_version	ver;
 
-	struct mdesc_node	*endpoint;
-
 	struct vio_version	*ver_table;
 	int			ver_table_entries;
 
@@ -365,7 +364,8 @@ struct vio_driver_state {
 
 #define viodbg(TYPE, f, a...) \
 do {	if (vio->debug & VIO_DEBUG_##TYPE) \
-		printk(KERN_INFO "vio: ID[%lu] " f, vio->channel_id, ## a); \
+		printk(KERN_INFO "vio: ID[%lu] " f, \
+		       vio->vdev->channel_id, ## a); \
 } while (0)
 
 extern int vio_register_driver(struct vio_driver *drv);
@@ -392,11 +392,10 @@ extern int vio_ldc_alloc(struct vio_driver_state *vio,
 			 struct ldc_channel_config *base_cfg, void *event_arg);
 extern void vio_ldc_free(struct vio_driver_state *vio);
 extern int vio_driver_init(struct vio_driver_state *vio, struct vio_dev *vdev,
-			   u8 dev_class, struct mdesc_node *channel_endpoint,
-			   struct vio_version *ver_table, int ver_table_size,
-			   struct vio_driver_ops *ops, char *name);
+			   u8 dev_class, struct vio_version *ver_table,
+			   int ver_table_size, struct vio_driver_ops *ops,
+			   char *name);
 
-extern struct mdesc_node *vio_find_endpoint(struct vio_dev *vdev);
 extern void vio_port_up(struct vio_driver_state *vio);
 
 #endif /* _SPARC64_VIO_H */