powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID

Based off 3bccd996 for ia64, convert powerpc to use the generic per-CPU
topology tracking, specifically:

    initialize per cpu numa_node entry in start_secondary
    remove the powerpc cpu_to_node()
    define CONFIG_USE_PERCPU_NUMA_NODE_ID if NUMA

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

3 files changed, 10 insertions, 13 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index e0998997943b..9125964af409 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -453,6 +453,10 @@ config NODES_SHIFT
         default "4"
         depends on NEED_MULTIPLE_NODES
 
+config USE_PERCPU_NUMA_NODE_ID
+        def_bool y
+        depends on NUMA
+
 config ARCH_SELECT_MEMORY_MODEL
         def_bool y
         depends on PPC64
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index c9202151079f..5ecf7ea52ad8 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -20,19 +20,6 @@ struct device_node;
 
 #include <asm/mmzone.h>
 
-static inline int cpu_to_node(int cpu)
-{
-        int nid;
-
-        nid = numa_cpu_lookup_table[cpu];
-
-        /*
-         * During early boot, the numa-cpu lookup table might not have been
-         * setup for all CPUs yet. In such cases, default to node 0.
-         */
-        return (nid < 0) ? 0 : nid;
-}
-
 #define parent_node(node)       (node)
 
 #define cpumask_of_node(node) ((node) == -1 ?                           \
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index e2a4232c5871..d7252adea759 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -390,6 +390,7 @@ void smp_prepare_boot_cpu(void)
 #ifdef CONFIG_PPC64
         paca[boot_cpuid].__current = current;
 #endif
+        set_numa_node(numa_cpu_lookup_table[boot_cpuid]);
         current_set[boot_cpuid] = task_thread_info(current);
 }
 
@@ -750,6 +751,11 @@ void start_secondary(void *unused)
         }
         traverse_core_siblings(cpu, true);
 
+        /*
+         * numa_node_id() works after this.
+         */
+        set_numa_node(numa_cpu_lookup_table[cpu]);
+
         smp_wmb();
         notify_cpu_starting(cpu);
         set_cpu_online(cpu, true);