diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 62262f2..aa701cc 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -496,13 +496,18 @@
 static struct mpic *mpic_find(unsigned int irq, unsigned int *is_ipi)
 {
 	unsigned int src = mpic_irq_to_hw(irq);
+	struct mpic *mpic;
 
 	if (irq < NUM_ISA_INTERRUPTS)
 		return NULL;
-	if (is_ipi)
-		*is_ipi = (src >= MPIC_VEC_IPI_0 && src <= MPIC_VEC_IPI_3);
 
-	return irq_desc[irq].chip_data;
+	mpic = irq_desc[irq].chip_data;
+
+	if (is_ipi)
+		*is_ipi = (src >= mpic->ipi_vecs[0] &&
+			   src <= mpic->ipi_vecs[3]);
+
+	return mpic;
 }
 
 /* Convert a cpu mask from logical to physical cpu numbers. */
@@ -540,7 +545,11 @@
 #ifdef CONFIG_SMP
 static irqreturn_t mpic_ipi_action(int irq, void *dev_id)
 {
-	smp_message_recv(mpic_irq_to_hw(irq) - MPIC_VEC_IPI_0);
+	struct mpic *mpic;
+
+	mpic = mpic_find(irq, NULL);
+	smp_message_recv(mpic_irq_to_hw(irq) - mpic->ipi_vecs[0]);
+
 	return IRQ_HANDLED;
 }
 #endif /* CONFIG_SMP */
@@ -663,7 +672,7 @@
 static void mpic_unmask_ipi(unsigned int irq)
 {
 	struct mpic *mpic = mpic_from_ipi(irq);
-	unsigned int src = mpic_irq_to_hw(irq) - MPIC_VEC_IPI_0;
+	unsigned int src = mpic_irq_to_hw(irq) - mpic->ipi_vecs[0];
 
 	DBG("%s: enable_ipi: %d (ipi %d)\n", mpic->name, irq, src);
 	mpic_ipi_write(src, mpic_ipi_read(src) & ~MPIC_VECPRI_MASK);
@@ -807,11 +816,11 @@
 
 	DBG("mpic: map virq %d, hwirq 0x%lx\n", virq, hw);
 
-	if (hw == MPIC_VEC_SPURRIOUS)
+	if (hw == mpic->spurious_vec)
 		return -EINVAL;
 
 #ifdef CONFIG_SMP
-	else if (hw >= MPIC_VEC_IPI_0) {
+	else if (hw >= mpic->ipi_vecs[0]) {
 		WARN_ON(!(mpic->flags & MPIC_PRIMARY));
 
 		DBG("mpic: mapping as IPI\n");
@@ -904,6 +913,7 @@
 	u32		reg;
 	const char	*vers;
 	int		i;
+	int		intvec_top;
 	u64		paddr = phys_addr;
 
 	mpic = alloc_bootmem(sizeof(struct mpic));
@@ -914,9 +924,9 @@
 	mpic->name = name;
 	mpic->of_node = of_node_get(node);
 
-	mpic->irqhost = irq_alloc_host(IRQ_HOST_MAP_LINEAR, 256,
+	mpic->irqhost = irq_alloc_host(IRQ_HOST_MAP_LINEAR, isu_size,
 				       &mpic_host_ops,
-				       MPIC_VEC_SPURRIOUS);
+				       flags & MPIC_LARGE_VECTORS ? 2048 : 256);
 	if (mpic->irqhost == NULL) {
 		of_node_put(node);
 		return NULL;
@@ -944,6 +954,21 @@
 	mpic->irq_count = irq_count;
 	mpic->num_sources = 0; /* so far */
 
+	if (flags & MPIC_LARGE_VECTORS)
+		intvec_top = 2047;
+	else
+		intvec_top = 255;
+
+	mpic->timer_vecs[0] = intvec_top - 8;
+	mpic->timer_vecs[1] = intvec_top - 7;
+	mpic->timer_vecs[2] = intvec_top - 6;
+	mpic->timer_vecs[3] = intvec_top - 5;
+	mpic->ipi_vecs[0]   = intvec_top - 4;
+	mpic->ipi_vecs[1]   = intvec_top - 3;
+	mpic->ipi_vecs[2]   = intvec_top - 2;
+	mpic->ipi_vecs[3]   = intvec_top - 1;
+	mpic->spurious_vec  = intvec_top;
+
 	/* Check for "big-endian" in device-tree */
 	if (node && get_property(node, "big-endian", NULL) != NULL)
 		mpic->flags |= MPIC_BIG_ENDIAN;
@@ -1084,11 +1109,6 @@
 	int i;
 
 	BUG_ON(mpic->num_sources == 0);
-	WARN_ON(mpic->num_sources > MPIC_VEC_IPI_0);
-
-	/* Sanitize source count */
-	if (mpic->num_sources > MPIC_VEC_IPI_0)
-		mpic->num_sources = MPIC_VEC_IPI_0;
 
 	printk(KERN_INFO "mpic: Initializing for %d sources\n", mpic->num_sources);
 
@@ -1104,7 +1124,7 @@
 			   i * MPIC_INFO(TIMER_STRIDE) +
 			   MPIC_INFO(TIMER_VECTOR_PRI),
 			   MPIC_VECPRI_MASK |
-			   (MPIC_VEC_TIMER_0 + i));
+			   (mpic->timer_vecs[0] + i));
 	}
 
 	/* Initialize IPIs to our reserved vectors and mark them disabled for now */
@@ -1113,7 +1133,7 @@
 		mpic_ipi_write(i,
 			       MPIC_VECPRI_MASK |
 			       (10 << MPIC_VECPRI_PRIORITY_SHIFT) |
-			       (MPIC_VEC_IPI_0 + i));
+			       (mpic->ipi_vecs[0] + i));
 	}
 
 	/* Initialize interrupt sources */
@@ -1136,8 +1156,8 @@
 			       1 << hard_smp_processor_id());
 	}
 	
-	/* Init spurrious vector */
-	mpic_write(mpic->gregs, MPIC_INFO(GREG_SPURIOUS), MPIC_VEC_SPURRIOUS);
+	/* Init spurious vector */
+	mpic_write(mpic->gregs, MPIC_INFO(GREG_SPURIOUS), mpic->spurious_vec);
 
 	/* Disable 8259 passthrough, if supported */
 	if (!(mpic->flags & MPIC_NO_PTHROU_DIS))
@@ -1184,9 +1204,9 @@
 
 	spin_lock_irqsave(&mpic_lock, flags);
 	if (is_ipi) {
-		reg = mpic_ipi_read(src - MPIC_VEC_IPI_0) &
+		reg = mpic_ipi_read(src - mpic->ipi_vecs[0]) &
 			~MPIC_VECPRI_PRIORITY_MASK;
-		mpic_ipi_write(src - MPIC_VEC_IPI_0,
+		mpic_ipi_write(src - mpic->ipi_vecs[0],
 			       reg | (pri << MPIC_VECPRI_PRIORITY_SHIFT));
 	} else {
 		reg = mpic_irq_read(src, MPIC_INFO(IRQ_VECTOR_PRI))
@@ -1207,7 +1227,7 @@
 
 	spin_lock_irqsave(&mpic_lock, flags);
 	if (is_ipi)
-		reg = mpic_ipi_read(src = MPIC_VEC_IPI_0);
+		reg = mpic_ipi_read(src = mpic->ipi_vecs[0]);
 	else
 		reg = mpic_irq_read(src, MPIC_INFO(IRQ_VECTOR_PRI));
 	spin_unlock_irqrestore(&mpic_lock, flags);
@@ -1313,7 +1333,7 @@
 #ifdef DEBUG_LOW
 	DBG("%s: get_one_irq(): %d\n", mpic->name, src);
 #endif
-	if (unlikely(src == MPIC_VEC_SPURRIOUS))
+	if (unlikely(src == mpic->spurious_vec))
 		return NO_IRQ;
 	return irq_linear_revmap(mpic->irqhost, src);
 }
@@ -1345,7 +1365,7 @@
 
 	for (i = 0; i < 4; i++) {
 		unsigned int vipi = irq_create_mapping(mpic->irqhost,
-						       MPIC_VEC_IPI_0 + i);
+						       mpic->ipi_vecs[0] + i);
 		if (vipi == NO_IRQ) {
 			printk(KERN_ERR "Failed to map IPI %d\n", i);
 			break;