1 files changed, 61 insertions, 16 deletions

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index d9a181351332..be05457631d4 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -150,6 +150,21 @@ static const int *of_get_associativity(struct device_node *dev)
         return of_get_property(dev, "ibm,associativity", NULL);
 }
 
+/*
+ * Returns the property linux,drconf-usable-memory if
+ * it exists (the property exists only in kexec/kdump kernels,
+ * added by kexec-tools)
+ */
+static const u32 *of_get_usable_memory(struct device_node *memory)
+{
+        const u32 *prop;
+        u32 len;
+        prop = of_get_property(memory, "linux,drconf-usable-memory", &len);
+        if (!prop || len < sizeof(unsigned int))
+                return 0;
+        return prop;
+}
+
 /* Returns nid in the range [0..MAX_NUMNODES-1], or -1 if no useful numa
  * info is found.
  */
@@ -487,14 +502,29 @@ static unsigned long __init numa_enforce_memory_limit(unsigned long start,
 }
 
 /*
+ * Reads the counter for a given entry in
+ * linux,drconf-usable-memory property
+ */
+static inline int __init read_usm_ranges(const u32 **usm)
+{
+        /*
+         * For each lmb in ibm,dynamic-memory a corresponding
+         * entry in linux,drconf-usable-memory property contains
+         * a counter followed by that many (base, size) duple.
+         * read the counter from linux,drconf-usable-memory
+         */
+        return read_n_cells(n_mem_size_cells, usm);
+}
+
+/*
  * Extract NUMA information from the ibm,dynamic-reconfiguration-memory
  * node.  This assumes n_mem_{addr,size}_cells have been set.
  */
 static void __init parse_drconf_memory(struct device_node *memory)
 {
-        const u32 *dm;
-        unsigned int n, rc;
-        unsigned long lmb_size, size;
+        const u32 *dm, *usm;
+        unsigned int n, rc, ranges, is_kexec_kdump = 0;
+        unsigned long lmb_size, base, size, sz;
         int nid;
         struct assoc_arrays aa;
 
@@ -510,6 +540,11 @@ static void __init parse_drconf_memory(struct device_node *memory)
         if (rc)
                 return;
 
+        /* check if this is a kexec/kdump kernel */
+        usm = of_get_usable_memory(memory);
+        if (usm != NULL)
+                is_kexec_kdump = 1;
+
         for (; n != 0; --n) {
                 struct of_drconf_cell drmem;
 
@@ -521,21 +556,31 @@ static void __init parse_drconf_memory(struct device_node *memory)
                     || !(drmem.flags & DRCONF_MEM_ASSIGNED))
                         continue;
 
-                nid = of_drconf_to_nid_single(&drmem, &aa);
+                base = drmem.base_addr;
+                size = lmb_size;
+                ranges = 1;
 
-                fake_numa_create_new_node(
-                                ((drmem.base_addr + lmb_size) >> PAGE_SHIFT),
+                if (is_kexec_kdump) {
+                        ranges = read_usm_ranges(&usm);
+                        if (!ranges) /* there are no (base, size) duple */
+                                continue;
+                }
+                do {
+                        if (is_kexec_kdump) {
+                                base = read_n_cells(n_mem_addr_cells, &usm);
+                                size = read_n_cells(n_mem_size_cells, &usm);
+                        }
+                        nid = of_drconf_to_nid_single(&drmem, &aa);
+                        fake_numa_create_new_node(
+                                ((base + size) >> PAGE_SHIFT),
                                            &nid);
-
-                node_set_online(nid);
-
-                size = numa_enforce_memory_limit(drmem.base_addr, lmb_size);
-                if (!size)
-                        continue;
-
-                add_active_range(nid, drmem.base_addr >> PAGE_SHIFT,
-                                 (drmem.base_addr >> PAGE_SHIFT)
-                                 + (size >> PAGE_SHIFT));
+                        node_set_online(nid);
+                        sz = numa_enforce_memory_limit(base, size);
+                        if (sz)
+                                add_active_range(nid, base >> PAGE_SHIFT,
+                                                 (base >> PAGE_SHIFT)
+                                                 + (sz >> PAGE_SHIFT));
+                } while (--ranges);
         }
 }