MN10300: And Panasonic AM34 subarch and implement SMP

[mirror_ubuntu-artful-kernel.git] / arch / mn10300 / kernel / process.c

diff --git a/arch/mn10300/kernel/process.c b/arch/mn10300/kernel/process.c
index 243e33cd874bcf366281d90e3d91e603f5ba9119..b2e85ed73a54f913271d7f321e9287986f98c5da 100644 (file)
--- a/arch/mn10300/kernel/process.c
+++ b/arch/mn10300/kernel/process.c
@@ -57,6 +57,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 void (*pm_power_off)(void);
 EXPORT_SYMBOL(pm_power_off);
 
+#if !defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
 /*
  * we use this if we don't have any better idle routine
  */
@@ -69,6 +70,35 @@ static void default_idle(void)
                local_irq_enable();
 }
 
+#else /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU  */
+/*
+ * On SMP it's slightly faster (but much more power-consuming!)
+ * to poll the ->work.need_resched flag instead of waiting for the
+ * cross-CPU IPI to arrive. Use this option with caution.
+ */
+static inline void poll_idle(void)
+{
+       int oldval;
+
+       local_irq_enable();
+
+       /*
+        * Deal with another CPU just having chosen a thread to
+        * run here:
+        */
+       oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
+
+       if (!oldval) {
+               set_thread_flag(TIF_POLLING_NRFLAG);
+               while (!need_resched())
+                       cpu_relax();
+               clear_thread_flag(TIF_POLLING_NRFLAG);
+       } else {
+               set_need_resched();
+       }
+}
+#endif /* !CONFIG_SMP || CONFIG_HOTPLUG_CPU */
+
 /*
  * the idle thread
  * - there's no useful work to be done, so just try to conserve power and have
@@ -77,8 +107,6 @@ static void default_idle(void)
  */
 void cpu_idle(void)
 {
-       int cpu = smp_processor_id();
-
        /* endless idle loop with no priority at all */
        for (;;) {
                while (!need_resched()) {
@@ -86,8 +114,13 @@ void cpu_idle(void)
 
                        smp_rmb();
                        idle = pm_idle;
-                       if (!idle)
+                       if (!idle) {
+#if defined(CONFIG_SMP) && !defined(CONFIG_HOTPLUG_CPU)
+                               idle = poll_idle;
+#else  /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
                                idle = default_idle;
+#endif /* CONFIG_SMP && !CONFIG_HOTPLUG_CPU */
+                       }
                        idle();
                }
 
@@ -233,7 +266,7 @@ int copy_thread(unsigned long clone_flags,
        }
 
        /* set up things up so the scheduler can start the new task */
-       p->thread.__frame = c_kregs;
+       p->thread.frame = c_kregs;
        p->thread.a3    = (unsigned long) c_kregs;
        p->thread.sp    = c_ksp;
        p->thread.pc    = (unsigned long) ret_from_fork;