sh: Support SCHED_MC for SH-X3 multi-cores.

This enables SCHED_MC support for SH-X3 multi-cores. Presently this is
just a simple wrapper around the possible map, but this allows for
tying in support for some of the more exotic NUMA clusters where we can
actually do something with the topology.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/include/asm/topology.h

@@ -40,6 +40,14 @@
 
 #endif
 
+#define mc_capable()    (1)
+
+const struct cpumask *cpu_coregroup_mask(unsigned int cpu);
+
+extern cpumask_t cpu_core_map[NR_CPUS];
+
+#define topology_core_cpumask(cpu)	(&cpu_core_map[cpu])
+
 #include <asm-generic/topology.h>
 
 #endif /* _ASM_SH_TOPOLOGY_H */

arch/sh/kernel/topology.c

@@ -16,6 +16,32 @@
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
 
+cpumask_t cpu_core_map[NR_CPUS];
+
+static cpumask_t cpu_coregroup_map(unsigned int cpu)
+{
+	/*
+	 * Presently all SH-X3 SMP cores are multi-cores, so just keep it
+	 * simple until we have a method for determining topology..
+	 */
+	return cpu_possible_map;
+}
+
+const struct cpumask *cpu_coregroup_mask(unsigned int cpu)
+{
+	return &cpu_core_map[cpu];
+}
+
+int arch_update_cpu_topology(void)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu)
+		cpu_core_map[cpu] = cpu_coregroup_map(cpu);
+
+	return 0;
+}
+
 static int __init topology_init(void)
 {
 	int i, ret;

arch/sh/mm/Kconfig

@@ -256,6 +256,15 @@ endchoice
 
 source "mm/Kconfig"
 
+config SCHED_MC
+	bool "Multi-core scheduler support"
+	depends on SMP
+	default y
+	help
+	  Multi-core scheduler support improves the CPU scheduler's decision
+	  making when dealing with multi-core CPU chips at a cost of slightly
+	  increased overhead in some places. If unsure say N here.
+
 endmenu
 
 menu "Cache configuration"