[MIPS] MT: Scheduler support for SMT

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 30 insertions, 0 deletions

diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
index 63989e9df4f9..335be9bcf0dc 100644
--- a/arch/mips/kernel/smp.c
+++ b/arch/mips/kernel/smp.c
@@ -56,6 +56,34 @@ EXPORT_SYMBOL(cpu_online_map);
 extern void __init calibrate_delay(void);
 extern void cpu_idle(void);
 
+/* Number of TCs (or siblings in Intel speak) per CPU core */
+int smp_num_siblings = 1;
+EXPORT_SYMBOL(smp_num_siblings);
+
+/* representing the TCs (or siblings in Intel speak) of each logical CPU */
+cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;
+EXPORT_SYMBOL(cpu_sibling_map);
+
+/* representing cpus for which sibling maps can be computed */
+static cpumask_t cpu_sibling_setup_map;
+
+static inline void set_cpu_sibling_map(int cpu)
+{
+        int i;
+
+        cpu_set(cpu, cpu_sibling_setup_map);
+
+        if (smp_num_siblings > 1) {
+                for_each_cpu_mask(i, cpu_sibling_setup_map) {
+                        if (cpu_data[cpu].core == cpu_data[i].core) {
+                                cpu_set(i, cpu_sibling_map[cpu]);
+                                cpu_set(cpu, cpu_sibling_map[i]);
+                        }
+                }
+        } else
+                cpu_set(cpu, cpu_sibling_map[cpu]);
+}
+
 /*
  * First C code run on the secondary CPUs after being started up by
  * the master.
@@ -85,6 +113,7 @@ asmlinkage __cpuinit void start_secondary(void)
         cpu_data[cpu].udelay_val = loops_per_jiffy;
 
         prom_smp_finish();
+        set_cpu_sibling_map(cpu);
 
         cpu_set(cpu, cpu_callin_map);
 
@@ -258,6 +287,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
         init_new_context(current, &init_mm);
         current_thread_info()->cpu = 0;
         plat_prepare_cpus(max_cpus);
+        set_cpu_sibling_map(0);
 #ifndef CONFIG_HOTPLUG_CPU
         cpu_present_map = cpu_possible_map;
 #endif