5 files changed, 162 insertions, 1 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index c2056ca04ae2..140cd1a9dc0c 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -165,6 +165,22 @@ config SMP
 
           If you don't know what to do here, say N.
 
+config SCHED_MC
+        bool "Multi-core scheduler support"
+        depends on SMP
+        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.
+
+config SCHED_SMT
+        bool "SMT scheduler support"
+        depends on SMP
+        help
+          Improves the CPU scheduler's decision making when dealing with
+          MultiThreading at a cost of slightly increased overhead in some
+          places. If unsure say N here.
+
 config NR_CPUS
         int "Maximum number of CPUs (2-32)"
         range 2 32
diff --git a/arch/arm64/include/asm/topology.h b/arch/arm64/include/asm/topology.h
new file mode 100644
index 000000000000..0172e6d76bf3
--- /dev/null
+++ b/arch/arm64/include/asm/topology.h
@@ -0,0 +1,39 @@
+#ifndef __ASM_TOPOLOGY_H
+#define __ASM_TOPOLOGY_H
+
+#ifdef CONFIG_SMP
+
+#include <linux/cpumask.h>
+
+struct cpu_topology {
+        int thread_id;
+        int core_id;
+        int cluster_id;
+        cpumask_t thread_sibling;
+        cpumask_t core_sibling;
+};
+
+extern struct cpu_topology cpu_topology[NR_CPUS];
+
+#define topology_physical_package_id(cpu)       (cpu_topology[cpu].cluster_id)
+#define topology_core_id(cpu)           (cpu_topology[cpu].core_id)
+#define topology_core_cpumask(cpu)      (&cpu_topology[cpu].core_sibling)
+#define topology_thread_cpumask(cpu)    (&cpu_topology[cpu].thread_sibling)
+
+#define mc_capable()    (cpu_topology[0].cluster_id != -1)
+#define smt_capable()   (cpu_topology[0].thread_id != -1)
+
+void init_cpu_topology(void);
+void store_cpu_topology(unsigned int cpuid);
+const struct cpumask *cpu_coregroup_mask(int cpu);
+
+#else
+
+static inline void init_cpu_topology(void) { }
+static inline void store_cpu_topology(unsigned int cpuid) { }
+
+#endif
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_ARM_TOPOLOGY_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index e52bcdc6f097..cfee8273fccb 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -14,7 +14,7 @@ arm64-obj-y		:= cputable.o debug-monitors.o entry.o irq.o fpsimd.o	\
 arm64-obj-$(CONFIG_COMPAT)              += sys32.o kuser32.o signal32.o         \
                                            sys_compat.o
 arm64-obj-$(CONFIG_MODULES)             += arm64ksyms.o module.o
-arm64-obj-$(CONFIG_SMP)                 += smp.o smp_spin_table.o
+arm64-obj-$(CONFIG_SMP)                 += smp.o smp_spin_table.o topology.o
 arm64-obj-$(CONFIG_HW_PERF_EVENTS)      += perf_event.o
 arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o
 arm64-obj-$(CONFIG_EARLY_PRINTK)        += early_printk.o
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 5070dc3b65d2..f0a141dd5655 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -114,6 +114,11 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle)
         return ret;
 }
 
+static void smp_store_cpu_info(unsigned int cpuid)
+{
+        store_cpu_topology(cpuid);
+}
+
 /*
  * This is the secondary CPU boot entry.  We're using this CPUs
  * idle thread stack, but a set of temporary page tables.
@@ -152,6 +157,8 @@ asmlinkage void secondary_start_kernel(void)
          */
         notify_cpu_starting(cpu);
 
+        smp_store_cpu_info(cpu);
+
         /*
          * OK, now it's safe to let the boot CPU continue.  Wait for
          * the CPU migration code to notice that the CPU is online
@@ -391,6 +398,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
         int err;
         unsigned int cpu, ncores = num_possible_cpus();
 
+        init_cpu_topology();
+
+        smp_store_cpu_info(smp_processor_id());
+
         /*
          * are we trying to boot more cores than exist?
          */
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
new file mode 100644
index 000000000000..3e06b0be4ec8
--- /dev/null
+++ b/arch/arm64/kernel/topology.c
@@ -0,0 +1,95 @@
+/*
+ * arch/arm64/kernel/topology.c
+ *
+ * Copyright (C) 2011,2013,2014 Linaro Limited.
+ *
+ * Based on the arm32 version written by Vincent Guittot in turn based on
+ * arch/sh/kernel/topology.c
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/percpu.h>
+#include <linux/node.h>
+#include <linux/nodemask.h>
+#include <linux/sched.h>
+
+#include <asm/topology.h>
+
+/*
+ * cpu topology table
+ */
+struct cpu_topology cpu_topology[NR_CPUS];
+EXPORT_SYMBOL_GPL(cpu_topology);
+
+const struct cpumask *cpu_coregroup_mask(int cpu)
+{
+        return &cpu_topology[cpu].core_sibling;
+}
+
+static void update_siblings_masks(unsigned int cpuid)
+{
+        struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
+        int cpu;
+
+        if (cpuid_topo->cluster_id == -1) {
+                /*
+                 * DT does not contain topology information for this cpu
+                 * reset it to default behaviour
+                 */
+                pr_debug("CPU%u: No topology information configured\n", cpuid);
+                cpuid_topo->core_id = 0;
+                cpumask_set_cpu(cpuid, &cpuid_topo->core_sibling);
+                cpumask_set_cpu(cpuid, &cpuid_topo->thread_sibling);
+                return;
+        }
+
+        /* update core and thread sibling masks */
+        for_each_possible_cpu(cpu) {
+                cpu_topo = &cpu_topology[cpu];
+
+                if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
+                        continue;
+
+                cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
+                if (cpu != cpuid)
+                        cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
+
+                if (cpuid_topo->core_id != cpu_topo->core_id)
+                        continue;
+
+                cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
+                if (cpu != cpuid)
+                        cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
+        }
+}
+
+void store_cpu_topology(unsigned int cpuid)
+{
+        update_siblings_masks(cpuid);
+}
+
+/*
+ * init_cpu_topology is called at boot when only one cpu is running
+ * which prevent simultaneous write access to cpu_topology array
+ */
+void __init init_cpu_topology(void)
+{
+        unsigned int cpu;
+
+        /* init core mask and power*/
+        for_each_possible_cpu(cpu) {
+                struct cpu_topology *cpu_topo = &cpu_topology[cpu];
+
+                cpu_topo->thread_id = -1;
+                cpu_topo->core_id =  -1;
+                cpu_topo->cluster_id = -1;
+                cpumask_clear(&cpu_topo->core_sibling);
+                cpumask_clear(&cpu_topo->thread_sibling);
+        }
+}