[PATCH 4/5 Trusty SRU] powerpc/numa: Enable USE_PERCPU_NUMA_NODE_ID

[Tim Gardner]

From: Nishanth Aravamudan <nacc at linux.vnet.ibm.com>

BugLink: http://bugs.launchpad.net/bugs/1332063

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 at linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
(cherry picked from commit 8c272261194dfda11cc046fbe808e052f6f284eb)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 arch/powerpc/Kconfig                |  4 ++++
 arch/powerpc/include/asm/topology.h | 13 -------------
 arch/powerpc/kernel/smp.c           |  6 ++++++
 3 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index db08cd2..6d45b60 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -439,6 +439,10 @@ 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 d0b5fca..8bbe8cc 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 c1cf4a1..2d6d186 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -384,6 +384,7 @@ 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);
 }
 
@@ -744,6 +745,11 @@ 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);
-- 
1.9.1