sh: CPU hotplug support.
This adds preliminary support for CPU hotplug for SH SMP systems.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c
index 21e7f8a..86cd6f9 100644
--- a/arch/sh/kernel/smp.c
+++ b/arch/sh/kernel/smp.c
@@ -79,6 +79,105 @@
per_cpu(cpu_state, cpu) = CPU_ONLINE;
}
+#ifdef CONFIG_HOTPLUG_CPU
+void native_cpu_die(unsigned int cpu)
+{
+ unsigned int i;
+
+ for (i = 0; i < 10; i++) {
+ smp_rmb();
+ if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
+ if (system_state == SYSTEM_RUNNING)
+ pr_info("CPU %u is now offline\n", cpu);
+
+ return;
+ }
+
+ msleep(100);
+ }
+
+ pr_err("CPU %u didn't die...\n", cpu);
+}
+
+int native_cpu_disable(unsigned int cpu)
+{
+ return cpu == 0 ? -EPERM : 0;
+}
+
+void play_dead_common(void)
+{
+ idle_task_exit();
+ irq_ctx_exit(raw_smp_processor_id());
+ mb();
+
+ __get_cpu_var(cpu_state) = CPU_DEAD;
+ local_irq_disable();
+}
+
+void native_play_dead(void)
+{
+ play_dead_common();
+}
+
+int __cpu_disable(void)
+{
+ unsigned int cpu = smp_processor_id();
+ struct task_struct *p;
+ int ret;
+
+ ret = mp_ops->cpu_disable(cpu);
+ if (ret)
+ return ret;
+
+ /*
+ * Take this CPU offline. Once we clear this, we can't return,
+ * and we must not schedule until we're ready to give up the cpu.
+ */
+ set_cpu_online(cpu, false);
+
+ /*
+ * OK - migrate IRQs away from this CPU
+ */
+ migrate_irqs();
+
+ /*
+ * Stop the local timer for this CPU.
+ */
+ local_timer_stop(cpu);
+
+ /*
+ * Flush user cache and TLB mappings, and then remove this CPU
+ * from the vm mask set of all processes.
+ */
+ flush_cache_all();
+ local_flush_tlb_all();
+
+ read_lock(&tasklist_lock);
+ for_each_process(p)
+ if (p->mm)
+ cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
+ read_unlock(&tasklist_lock);
+
+ return 0;
+}
+#else /* ... !CONFIG_HOTPLUG_CPU */
+int native_cpu_disable(void)
+{
+ return -ENOSYS;
+}
+
+void native_cpu_die(unsigned int cpu)
+{
+ /* We said "no" in __cpu_disable */
+ BUG();
+}
+
+void native_play_dead(void)
+{
+ BUG();
+}
+#endif
+
asmlinkage void __cpuinit start_secondary(void)
{
unsigned int cpu = smp_processor_id();
@@ -88,8 +187,8 @@
atomic_inc(&mm->mm_count);
atomic_inc(&mm->mm_users);
current->active_mm = mm;
- BUG_ON(current->mm);
enter_lazy_tlb(mm, current);
+ local_flush_tlb_all();
per_cpu_trap_init();
@@ -156,6 +255,7 @@
break;
udelay(10);
+ barrier();
}
if (cpu_online(cpu))
@@ -270,7 +370,6 @@
* behalf of debugees, kswapd stealing pages from another process etc).
* Kanoj 07/00.
*/
-
void flush_tlb_mm(struct mm_struct *mm)
{
preempt_disable();