1 files changed, 37 insertions, 6 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 87d83c56b31e..3a2dc7e6586a 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -888,9 +888,10 @@ static u64 __init dt_mem_next_cell(int s, cell_t **cellp)
  */
 static int __init early_init_dt_scan_drconf_memory(unsigned long node)
 {
-        cell_t *dm, *ls;
+        cell_t *dm, *ls, *usm;
         unsigned long l, n, flags;
         u64 base, size, lmb_size;
+        unsigned int is_kexec_kdump = 0, rngs;
 
         ls = (cell_t *)of_get_flat_dt_prop(node, "ibm,lmb-size", &l);
         if (ls == NULL || l < dt_root_size_cells * sizeof(cell_t))
@@ -905,6 +906,12 @@ static int __init early_init_dt_scan_drconf_memory(unsigned long node)
         if (l < (n * (dt_root_addr_cells + 4) + 1) * sizeof(cell_t))
                 return 0;
 
+        /* check if this is a kexec/kdump kernel. */
+        usm = (cell_t *)of_get_flat_dt_prop(node, "linux,drconf-usable-memory",
+                                                 &l);
+        if (usm != NULL)
+                is_kexec_kdump = 1;
+
         for (; n != 0; --n) {
                 base = dt_mem_next_cell(dt_root_addr_cells, &dm);
                 flags = dm[3];
@@ -915,13 +922,34 @@ static int __init early_init_dt_scan_drconf_memory(unsigned long node)
                 if ((flags & 0x80) || !(flags & 0x8))
                         continue;
                 size = lmb_size;
-                if (iommu_is_off) {
-                        if (base >= 0x80000000ul)
+                rngs = 1;
+                if (is_kexec_kdump) {
+                        /*
+                         * For each lmb in ibm,dynamic-memory, a corresponding
+                         * entry in linux,drconf-usable-memory property contains
+                         * a counter 'p' followed by 'p' (base, size) duple.
+                         * Now read the counter from
+                         * linux,drconf-usable-memory property
+                         */
+                        rngs = dt_mem_next_cell(dt_root_size_cells, &usm);
+                        if (!rngs) /* there are no (base, size) duple */
                                 continue;
-                        if ((base + size) > 0x80000000ul)
-                                size = 0x80000000ul - base;
                 }
-                lmb_add(base, size);
+                do {
+                        if (is_kexec_kdump) {
+                                base = dt_mem_next_cell(dt_root_addr_cells,
+                                                         &usm);
+                                size = dt_mem_next_cell(dt_root_size_cells,
+                                                         &usm);
+                        }
+                        if (iommu_is_off) {
+                                if (base >= 0x80000000ul)
+                                        continue;
+                                if ((base + size) > 0x80000000ul)
+                                        size = 0x80000000ul - base;
+                        }
+                        lmb_add(base, size);
+                } while (--rngs);
         }
         lmb_dump_all();
         return 0;
@@ -1164,6 +1192,9 @@ void __init early_init_devtree(void *params)
 
         /* Reserve LMB regions used by kernel, initrd, dt, etc... */
         lmb_reserve(PHYSICAL_START, __pa(klimit) - PHYSICAL_START);
+        /* If relocatable, reserve first 32k for interrupt vectors etc. */
+        if (PHYSICAL_START > MEMORY_START)
+                lmb_reserve(MEMORY_START, 0x8000);
         reserve_kdump_trampoline();
         reserve_crashkernel();
         early_reserve_mem();