1 files changed, 117 insertions, 21 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index c77bc3a1c722..86d49045daed 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -15,6 +15,28 @@
 #include <linux/stop_machine.h>
 #include <linux/mutex.h>
 
+/*
+ * Represents all cpu's present in the system
+ * In systems capable of hotplug, this map could dynamically grow
+ * as new cpu's are detected in the system via any platform specific
+ * method, such as ACPI for e.g.
+ */
+cpumask_t cpu_present_map __read_mostly;
+EXPORT_SYMBOL(cpu_present_map);
+
+#ifndef CONFIG_SMP
+
+/*
+ * Represents all cpu's that are currently online.
+ */
+cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_online_map);
+
+cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_possible_map);
+
+#else /* CONFIG_SMP */
+
 /* Serializes the updates to cpu_online_map, cpu_present_map */
 static DEFINE_MUTEX(cpu_add_remove_lock);
 
@@ -42,6 +64,8 @@ void __init cpu_hotplug_init(void)
         cpu_hotplug.refcount = 0;
 }
 
+cpumask_t cpu_active_map;
+
 #ifdef CONFIG_HOTPLUG_CPU
 
 void get_online_cpus(void)
@@ -175,13 +199,14 @@ static int __ref take_cpu_down(void *_param)
         struct take_cpu_down_param *param = _param;
         int err;
 
-        raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
-                                param->hcpu);
         /* Ensure this CPU doesn't handle any more interrupts. */
         err = __cpu_disable();
         if (err < 0)
                 return err;
 
+        raw_notifier_call_chain(&cpu_chain, CPU_DYING | param->mod,
+                                param->hcpu);
+
         /* Force idle task to run as soon as we yield: it should
            immediately notice cpu is offline and die quickly. */
         sched_idle_next();
@@ -192,7 +217,6 @@ static int __ref take_cpu_down(void *_param)
 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 {
         int err, nr_calls = 0;
-        struct task_struct *p;
         cpumask_t old_allowed, tmp;
         void *hcpu = (void *)(long)cpu;
         unsigned long mod = tasks_frozen ? CPU_TASKS_FROZEN : 0;
@@ -225,21 +249,18 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
         cpus_setall(tmp);
         cpu_clear(cpu, tmp);
         set_cpus_allowed_ptr(current, &tmp);
+        tmp = cpumask_of_cpu(cpu);
 
-        p = __stop_machine_run(take_cpu_down, &tcd_param, cpu);
-
-        if (IS_ERR(p) || cpu_online(cpu)) {
+        err = __stop_machine(take_cpu_down, &tcd_param, &tmp);
+        if (err) {
                 /* CPU didn't die: tell everyone.  Can't complain. */
                 if (raw_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED | mod,
                                             hcpu) == NOTIFY_BAD)
                         BUG();
 
-                if (IS_ERR(p)) {
-                        err = PTR_ERR(p);
-                        goto out_allowed;
-                }
-                goto out_thread;
+                goto out_allowed;
         }
+        BUG_ON(cpu_online(cpu));
 
         /* Wait for it to sleep (leaving idle task). */
         while (!idle_cpu(cpu))
@@ -255,12 +276,15 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen)
 
         check_for_tasks(cpu);
 
-out_thread:
-        err = kthread_stop(p);
 out_allowed:
         set_cpus_allowed_ptr(current, &old_allowed);
 out_release:
         cpu_hotplug_done();
+        if (!err) {
+                if (raw_notifier_call_chain(&cpu_chain, CPU_POST_DEAD | mod,
+                                            hcpu) == NOTIFY_BAD)
+                        BUG();
+        }
         return err;
 }
 
@@ -269,14 +293,34 @@ int __ref cpu_down(unsigned int cpu)
         int err = 0;
 
         cpu_maps_update_begin();
-        if (cpu_hotplug_disabled)
+
+        if (cpu_hotplug_disabled) {
                 err = -EBUSY;
-        else
-                err = _cpu_down(cpu, 0);
+                goto out;
+        }
+
+        cpu_clear(cpu, cpu_active_map);
+
+        /*
+         * Make sure the all cpus did the reschedule and are not
+         * using stale version of the cpu_active_map.
+         * This is not strictly necessary becuase stop_machine()
+         * that we run down the line already provides the required
+         * synchronization. But it's really a side effect and we do not
+         * want to depend on the innards of the stop_machine here.
+         */
+        synchronize_sched();
 
+        err = _cpu_down(cpu, 0);
+
+        if (cpu_online(cpu))
+                cpu_set(cpu, cpu_active_map);
+
+out:
         cpu_maps_update_done();
         return err;
 }
+EXPORT_SYMBOL(cpu_down);
 #endif /*CONFIG_HOTPLUG_CPU*/
 
 /* Requires cpu_add_remove_lock to be held */
@@ -306,6 +350,8 @@ static int __cpuinit _cpu_up(unsigned int cpu, int tasks_frozen)
                 goto out_notify;
         BUG_ON(!cpu_online(cpu));
 
+        cpu_set(cpu, cpu_active_map);
+
         /* Now call notifier in preparation. */
         raw_notifier_call_chain(&cpu_chain, CPU_ONLINE | mod, hcpu);
 
@@ -324,7 +370,7 @@ int __cpuinit cpu_up(unsigned int cpu)
         if (!cpu_isset(cpu, cpu_possible_map)) {
                 printk(KERN_ERR "can't online cpu %d because it is not "
                         "configured as may-hotadd at boot time\n", cpu);
-#if defined(CONFIG_IA64) || defined(CONFIG_X86_64) || defined(CONFIG_S390)
+#if defined(CONFIG_IA64) || defined(CONFIG_X86_64)
                 printk(KERN_ERR "please check additional_cpus= boot "
                                 "parameter\n");
 #endif
@@ -332,11 +378,15 @@ int __cpuinit cpu_up(unsigned int cpu)
         }
 
         cpu_maps_update_begin();
-        if (cpu_hotplug_disabled)
+
+        if (cpu_hotplug_disabled) {
                 err = -EBUSY;
-        else
-                err = _cpu_up(cpu, 0);
+                goto out;
+        }
 
+        err = _cpu_up(cpu, 0);
+
+out:
         cpu_maps_update_done();
         return err;
 }
@@ -390,7 +440,7 @@ void __ref enable_nonboot_cpus(void)
                 goto out;
 
         printk("Enabling non-boot CPUs ...\n");
-        for_each_cpu_mask(cpu, frozen_cpus) {
+        for_each_cpu_mask_nr(cpu, frozen_cpus) {
                 error = _cpu_up(cpu, 1);
                 if (!error) {
                         printk("CPU%d is up\n", cpu);
@@ -403,3 +453,49 @@ out:
         cpu_maps_update_done();
 }
 #endif /* CONFIG_PM_SLEEP_SMP */
+
+/**
+ * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
+ * @cpu: cpu that just started
+ *
+ * This function calls the cpu_chain notifiers with CPU_STARTING.
+ * It must be called by the arch code on the new cpu, before the new cpu
+ * enables interrupts and before the "boot" cpu returns from __cpu_up().
+ */
+void notify_cpu_starting(unsigned int cpu)
+{
+        unsigned long val = CPU_STARTING;
+
+#ifdef CONFIG_PM_SLEEP_SMP
+        if (cpu_isset(cpu, frozen_cpus))
+                val = CPU_STARTING_FROZEN;
+#endif /* CONFIG_PM_SLEEP_SMP */
+        raw_notifier_call_chain(&cpu_chain, val, (void *)(long)cpu);
+}
+
+#endif /* CONFIG_SMP */
+
+/*
+ * cpu_bit_bitmap[] is a special, "compressed" data structure that
+ * represents all NR_CPUS bits binary values of 1<<nr.
+ *
+ * It is used by cpumask_of_cpu() to get a constant address to a CPU
+ * mask value that has a single bit set only.
+ */
+
+/* cpu_bit_bitmap[0] is empty - so we can back into it */
+#define MASK_DECLARE_1(x)       [x+1][0] = 1UL << (x)
+#define MASK_DECLARE_2(x)       MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
+#define MASK_DECLARE_4(x)       MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
+#define MASK_DECLARE_8(x)       MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
+
+const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
+
+        MASK_DECLARE_8(0),      MASK_DECLARE_8(8),
+        MASK_DECLARE_8(16),     MASK_DECLARE_8(24),
+#if BITS_PER_LONG > 32
+        MASK_DECLARE_8(32),     MASK_DECLARE_8(40),
+        MASK_DECLARE_8(48),     MASK_DECLARE_8(56),
+#endif
+};
+EXPORT_SYMBOL_GPL(cpu_bit_bitmap);