4 files changed, 67 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 7cb77c20fc5d..3d677ac99659 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -38,6 +38,7 @@
 #include <asm/iommu.h>
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
+#include <asm/kdump.h>
 
 #define DBG(...)
 
@@ -440,8 +441,37 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
         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 = tbl->it_size - KDUMP_MIN_TCE_ENTRIES;
+                                index < tbl->it_size; 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 --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index d03a8b078f9d..8cfb5706790e 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -92,6 +92,15 @@ static void tce_free_pSeries(struct iommu_table *tbl, long index, long npages)
                 *(tcep++) = 0;
 }
 
+static unsigned long tce_get_pseries(struct iommu_table *tbl, long index)
+{
+        u64 *tcep;
+
+        index <<= TCE_PAGE_FACTOR;
+        tcep = ((u64 *)tbl->it_base) + index;
+
+        return *tcep;
+}
 
 static void tce_build_pSeriesLP(struct iommu_table *tbl, long tcenum,
                                 long npages, unsigned long uaddr,
@@ -235,6 +244,25 @@ static void tce_freemulti_pSeriesLP(struct iommu_table *tbl, long tcenum, long n
         }
 }
 
+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)
@@ -254,7 +282,10 @@ static void iommu_table_setparms(struct pci_controller *phb,
         }
 
         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;
 
@@ -560,11 +591,13 @@ 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 --git a/include/asm-powerpc/kdump.h b/include/asm-powerpc/kdump.h
index 5a5c3b5ab1e0..dc1574c945f8 100644
--- a/include/asm-powerpc/kdump.h
+++ b/include/asm-powerpc/kdump.h
@@ -15,6 +15,8 @@
 #define KDUMP_TRAMPOLINE_START  0x0100
 #define KDUMP_TRAMPOLINE_END    0x3000
 
+#define KDUMP_MIN_TCE_ENTRIES   2048
+
 #else /* !CONFIG_CRASH_DUMP */
 
 #define PHYSICAL_START  0x0
diff --git a/include/asm-powerpc/machdep.h b/include/asm-powerpc/machdep.h
index 73db1f71329d..eba133d149a7 100644
--- a/include/asm-powerpc/machdep.h
+++ b/include/asm-powerpc/machdep.h
@@ -81,6 +81,8 @@ 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);