diff -Naurp 2617-rc6-git5.orig/arch/powerpc/kernel/iommu.c 2617-rc6-git5/arch/powerpc/kernel/iommu.c
--- 2617-rc6-git5.orig/arch/powerpc/kernel/iommu.c	2006-06-13 19:46:43.000000000 -0700
+++ 2617-rc6-git5/arch/powerpc/kernel/iommu.c	2006-06-14 20:50:33.000000000 -0700
@@ -38,6 +38,7 @@
 #include <asm/iommu.h>
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
+#include <asm/kdump.h>
 
 #define DBG(...)
 
@@ -439,8 +440,36 @@ struct iommu_table *iommu_init_table(str
 	tbl->it_largehint = tbl->it_halfpoint;
 	spin_lock_init(&tbl->it_lock);
 
+#ifdef CONFIG_CRASH_DUMP
+	if (ppc_md.tce_get) {
+		unsigned long index, tceval;
+		unsigned long tcecount = 0;
+
+		/* 
+		 * Reserve the existing mappings left by the first kernel.
+		 */
+		for (index = 0; index < tbl->it_size; index++) {
+			tceval = ppc_md.tce_get(tbl, index + tbl->it_offset);
+			/*
+			 * Freed TCE entry contains 0x7fffffffffffffff on JS20
+			 */
+			if (tceval && (tceval != 0x7fffffffffffffffUL)) {
+				__set_bit(index, tbl->it_map);
+				tcecount++;
+			}
+		}
+		if ((tbl->it_size - tcecount) < KDUMP_MIN_TCE_ENTRIES) {
+			printk(KERN_WARNING "TCE table is full; ");
+			printk(KERN_WARNING "freeing %d entries for the kdump boot\n", 
+				KDUMP_MIN_TCE_ENTRIES);
+			for (index = 0; index < KDUMP_MIN_TCE_ENTRIES; index++)
+				__clear_bit(index, tbl->it_map);
+		}
+	}
+#else
 	/* Clear the hardware table in case firmware left allocations in it */
 	ppc_md.tce_free(tbl, tbl->it_offset, tbl->it_size);
+#endif
 
 	if (!welcomed) {
 		printk(KERN_INFO "IOMMU table initialized, virtual merging %s\n",
diff -Naurp 2617-rc6-git5.orig/arch/powerpc/platforms/pseries/iommu.c 2617-rc6-git5/arch/powerpc/platforms/pseries/iommu.c
--- 2617-rc6-git5.orig/arch/powerpc/platforms/pseries/iommu.c	2006-06-13 19:46:38.000000000 -0700
+++ 2617-rc6-git5/arch/powerpc/platforms/pseries/iommu.c	2006-06-13 19:48:51.000000000 -0700
@@ -97,6 +97,14 @@ static void tce_free_pSeries(struct iomm
 	}
 }
 
+static unsigned long tce_get_pseries(struct iommu_table *tbl, long index)
+{
+	union tce_entry *tp;
+
+	index <<= TCE_PAGE_FACTOR;
+	tp  = ((union tce_entry *)tbl->it_base) + index;
+	return tp->te_word;
+}
 
 static void tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
 				long npages, unsigned long uaddr,
@@ -253,6 +261,25 @@ static void tce_freemulti_pSeriesLP(stru
 	}
 }
 
+static unsigned long tce_get_pSeriesLP(struct iommu_table *tbl, long tcenum)
+{
+	u64 rc;
+	unsigned long tce_ret;
+
+	tcenum <<= TCE_PAGE_FACTOR;
+	rc = plpar_tce_get((u64)tbl->it_index, (u64)tcenum << 12, &tce_ret);
+	
+	if (rc && printk_ratelimit()) {
+		printk("tce_get_pSeriesLP: plpar_tce_get failed. rc=%ld\n",
+			rc);
+		printk("\tindex   = 0x%lx\n", (u64)tbl->it_index);
+		printk("\ttcenum  = 0x%lx\n", (u64)tcenum);
+		show_stack(current, (unsigned long *)__get_SP());
+	}
+
+	return tce_ret;
+}
+
 static void iommu_table_setparms(struct pci_controller *phb,
 				 struct device_node *dn,
 				 struct iommu_table *tbl) 
@@ -272,7 +299,10 @@ static void iommu_table_setparms(struct 
 	}
 
 	tbl->it_base = (unsigned long)__va(*basep);
+
+#ifndef CONFIG_CRASH_DUMP
 	memset((void *)tbl->it_base, 0, *sizep);
+#endif
 
 	tbl->it_busno = phb->bus->number;
 	
@@ -588,11 +618,13 @@ void iommu_init_early_pSeries(void)
 			ppc_md.tce_build = tce_build_pSeriesLP;
 			ppc_md.tce_free	 = tce_free_pSeriesLP;
 		}
+		ppc_md.tce_get   = tce_get_pSeriesLP;
 		ppc_md.iommu_bus_setup = iommu_bus_setup_pSeriesLP;
 		ppc_md.iommu_dev_setup = iommu_dev_setup_pSeriesLP;
 	} else {
 		ppc_md.tce_build = tce_build_pSeries;
 		ppc_md.tce_free  = tce_free_pSeries;
+		ppc_md.tce_get   = tce_get_pseries;
 		ppc_md.iommu_bus_setup = iommu_bus_setup_pSeries;
 		ppc_md.iommu_dev_setup = iommu_dev_setup_pSeries;
 	}
diff -Naurp 2617-rc6-git5.orig/include/asm-powerpc/kdump.h 2617-rc6-git5/include/asm-powerpc/kdump.h
--- 2617-rc6-git5.orig/include/asm-powerpc/kdump.h	2006-06-13 19:47:27.000000000 -0700
+++ 2617-rc6-git5/include/asm-powerpc/kdump.h	2006-06-13 19:48:15.000000000 -0700
@@ -8,6 +8,8 @@
 #define KDUMP_TRAMPOLINE_START	0x0100
 #define KDUMP_TRAMPOLINE_END	0x3000
 
+#define KDUMP_MIN_TCE_ENTRIES	10
+
 extern void kdump_setup(void);
 
 #endif /* __PPC64_KDUMP_H */
diff -Naurp 2617-rc6-git5.orig/include/asm-powerpc/machdep.h 2617-rc6-git5/include/asm-powerpc/machdep.h
--- 2617-rc6-git5.orig/include/asm-powerpc/machdep.h	2006-06-13 19:47:15.000000000 -0700
+++ 2617-rc6-git5/include/asm-powerpc/machdep.h	2006-06-13 19:48:02.000000000 -0700
@@ -82,6 +82,8 @@ struct machdep_calls {
 	void		(*tce_free)(struct iommu_table *tbl,
 				    long index,
 				    long npages);
+	unsigned long	(*tce_get)(struct iommu_table *tbl,
+				    long index);
 	void		(*tce_flush)(struct iommu_table *tbl);
 	void		(*iommu_dev_setup)(struct pci_dev *dev);
 	void		(*iommu_bus_setup)(struct pci_bus *bus);