return 0;
}
+static int bringup_wait_for_ap(unsigned int cpu)
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+
+ wait_for_completion(&st->done);
+ return st->result;
+}
+
static int bringup_cpu(unsigned int cpu)
{
struct task_struct *idle = idle_thread_get(cpu);
cpu_notify(CPU_UP_CANCELED, cpu);
return ret;
}
+ ret = bringup_wait_for_ap(cpu);
BUG_ON(!cpu_online(cpu));
- return 0;
+ return ret;
}
/*
/* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */
static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st)
{
- enum cpuhp_state target = max((int)st->target, CPUHP_AP_ONLINE);
+ enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU);
return cpuhp_down_callbacks(cpu, st, cpuhp_ap_states, target);
}
ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb);
}
} else {
+ /* Cannot happen .... */
+ BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
+
/* Regular hotplug work */
if (st->state < st->target)
ret = cpuhp_ap_online(cpu, st);
}
/* Regular hotplug invocation of the AP hotplug thread */
-static int cpuhp_kick_ap_work(unsigned int cpu)
+static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st)
{
- struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
- enum cpuhp_state state = st->state;
-
- trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work);
st->result = 0;
st->cb = NULL;
/*
smp_mb();
st->should_run = true;
wake_up_process(st->thread);
+}
+
+static int cpuhp_kick_ap_work(unsigned int cpu)
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+ enum cpuhp_state state = st->state;
+
+ trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work);
+ __cpuhp_kick_ap_work(st);
wait_for_completion(&st->done);
trace_cpuhp_exit(cpu, st->state, state, st->result);
return st->result;
static int takedown_cpu(unsigned int cpu)
{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int err;
/*
else
synchronize_rcu();
+ /* Park the smpboot threads */
+ kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread);
+ smpboot_park_threads(cpu);
+
/*
* Prevent irq alloc/free while the dying cpu reorganizes the
* interrupt affinities.
*
* Wait for the stop thread to go away.
*/
- while (!per_cpu(cpu_dead_idle, cpu))
- cpu_relax();
- smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */
- per_cpu(cpu_dead_idle, cpu) = false;
+ wait_for_completion(&st->done);
+ BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
/* Interrupts are moved away from the dying cpu, reenable alloc/free */
irq_unlock_sparse();
return 0;
}
+static void cpuhp_complete_idle_dead(void *arg)
+{
+ struct cpuhp_cpu_state *st = arg;
+
+ complete(&st->done);
+}
+
+void cpuhp_report_idle_dead(void)
+{
+ struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+
+ BUG_ON(st->state != CPUHP_AP_OFFLINE);
+ rcu_report_dead(smp_processor_id());
+ st->state = CPUHP_AP_IDLE_DEAD;
+ /*
+ * We cannot call complete after rcu_report_dead() so we delegate it
+ * to an online cpu.
+ */
+ smp_call_function_single(cpumask_first(cpu_online_mask),
+ cpuhp_complete_idle_dead, st, 0);
+}
+
#else
#define notify_down_prepare NULL
#define takedown_cpu NULL
prev_state = st->state;
st->target = target;
+ /*
+ * If the current CPU state is in the range of the AP hotplug thread,
+ * then we need to kick the thread.
+ */
+ if (st->state > CPUHP_TEARDOWN_CPU) {
+ ret = cpuhp_kick_ap_work(cpu);
+ /*
+ * The AP side has done the error rollback already. Just
+ * return the error code..
+ */
+ if (ret)
+ goto out;
+
+ /*
+ * We might have stopped still in the range of the AP hotplug
+ * thread. Nothing to do anymore.
+ */
+ if (st->state > CPUHP_TEARDOWN_CPU)
+ goto out;
+ }
+ /*
+ * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need
+ * to do the further cleanups.
+ */
ret = cpuhp_down_callbacks(cpu, st, cpuhp_bp_states, target);
hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;
-
+out:
cpu_hotplug_done();
/* This post dead nonsense must die */
if (!ret && hasdied)
/*
* Called from the idle task. We need to set active here, so we can kick off
- * the stopper thread.
+ * the stopper thread and unpark the smpboot threads. If the target state is
+ * beyond CPUHP_AP_ONLINE_IDLE we kick cpuhp thread and let it bring up the
+ * cpu further.
*/
-static int cpuhp_set_cpu_active(unsigned int cpu)
+void cpuhp_online_idle(enum cpuhp_state state)
{
+ struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+ unsigned int cpu = smp_processor_id();
+
+ /* Happens for the boot cpu */
+ if (state != CPUHP_AP_ONLINE_IDLE)
+ return;
+
+ st->state = CPUHP_AP_ONLINE_IDLE;
+
/* The cpu is marked online, set it active now */
set_cpu_active(cpu, true);
- /* Unpark the stopper thread */
+ /* Unpark the stopper thread and the hotplug thread of this cpu */
stop_machine_unpark(cpu);
- return 0;
+ kthread_unpark(st->thread);
+
+ /* Should we go further up ? */
+ if (st->target > CPUHP_AP_ONLINE_IDLE)
+ __cpuhp_kick_ap_work(st);
+ else
+ complete(&st->done);
}
/* Requires cpu_add_remove_lock to be held */
cpuhp_tasks_frozen = tasks_frozen;
st->target = target;
+ /*
+ * If the current CPU state is in the range of the AP hotplug thread,
+ * then we need to kick the thread once more.
+ */
+ if (st->state > CPUHP_BRINGUP_CPU) {
+ ret = cpuhp_kick_ap_work(cpu);
+ /*
+ * The AP side has done the error rollback already. Just
+ * return the error code..
+ */
+ if (ret)
+ goto out;
+ }
+
+ /*
+ * Try to reach the target state. We max out on the BP at
+ * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is
+ * responsible for bringing it up to the target state.
+ */
+ target = min((int)target, CPUHP_BRINGUP_CPU);
ret = cpuhp_up_callbacks(cpu, st, cpuhp_bp_states, target);
out:
cpu_hotplug_done();
.teardown = NULL,
.cant_stop = true,
},
+ /*
+ * Preparatory and dead notifiers. Will be replaced once the notifiers
+ * are converted to states.
+ */
[CPUHP_NOTIFY_PREPARE] = {
.name = "notify:prepare",
.startup = notify_prepare,
.skip_onerr = true,
.cant_stop = true,
},
+ /* Kicks the plugged cpu into life */
[CPUHP_BRINGUP_CPU] = {
.name = "cpu:bringup",
.startup = bringup_cpu,
.teardown = NULL,
.cant_stop = true,
},
+ /*
+ * Handled on controll processor until the plugged processor manages
+ * this itself.
+ */
[CPUHP_TEARDOWN_CPU] = {
.name = "cpu:teardown",
.startup = NULL,
.teardown = takedown_cpu,
.cant_stop = true,
},
- [CPUHP_CPU_SET_ACTIVE] = {
- .name = "cpu:active",
- .startup = cpuhp_set_cpu_active,
- .teardown = NULL,
- },
- [CPUHP_SMPBOOT_THREADS] = {
- .name = "smpboot:threads",
- .startup = smpboot_unpark_threads,
- .teardown = smpboot_park_threads,
- },
- [CPUHP_NOTIFY_ONLINE] = {
- .name = "notify:online",
- .startup = notify_online,
- .teardown = notify_down_prepare,
- .cant_stop = true,
- },
#endif
- [CPUHP_ONLINE] = {
- .name = "online",
- .startup = NULL,
- .teardown = NULL,
- },
};
/* Application processor state steps */
static struct cpuhp_step cpuhp_ap_states[] = {
#ifdef CONFIG_SMP
+ /* Final state before CPU kills itself */
+ [CPUHP_AP_IDLE_DEAD] = {
+ .name = "idle:dead",
+ },
+ /*
+ * Last state before CPU enters the idle loop to die. Transient state
+ * for synchronization.
+ */
+ [CPUHP_AP_OFFLINE] = {
+ .name = "ap:offline",
+ .cant_stop = true,
+ },
+ /*
+ * Low level startup/teardown notifiers. Run with interrupts
+ * disabled. Will be removed once the notifiers are converted to
+ * states.
+ */
[CPUHP_AP_NOTIFY_STARTING] = {
.name = "notify:starting",
.startup = notify_starting,
.skip_onerr = true,
.cant_stop = true,
},
+ /* Entry state on starting. Interrupts enabled from here on. Transient
+ * state for synchronsization */
+ [CPUHP_AP_ONLINE] = {
+ .name = "ap:online",
+ },
+ /* Handle smpboot threads park/unpark */
+ [CPUHP_AP_SMPBOOT_THREADS] = {
+ .name = "smpboot:threads",
+ .startup = smpboot_unpark_threads,
+ .teardown = NULL,
+ },
+ /*
+ * Online/down_prepare notifiers. Will be removed once the notifiers
+ * are converted to states.
+ */
+ [CPUHP_AP_NOTIFY_ONLINE] = {
+ .name = "notify:online",
+ .startup = notify_online,
+ .teardown = notify_down_prepare,
+ },
#endif
+ /*
+ * The dynamically registered state space is here
+ */
+
+ /* CPU is fully up and running. */
[CPUHP_ONLINE] = {
.name = "online",
.startup = NULL,
static bool cpuhp_is_ap_state(enum cpuhp_state state)
{
- return (state >= CPUHP_AP_OFFLINE && state <= CPUHP_AP_ONLINE);
+ /*
+ * The extra check for CPUHP_TEARDOWN_CPU is only for documentation
+ * purposes as that state is handled explicitely in cpu_down.
+ */
+ return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
}
static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
return cpuhp_get_step(state)->teardown;
}
-/* Helper function to run callback on the target cpu */
-static void cpuhp_on_cpu_cb(void *__cb)
-{
- int (*cb)(unsigned int cpu) = __cb;
-
- BUG_ON(cb(smp_processor_id()));
-}
-
/*
* Call the startup/teardown function for a step either on the AP or
* on the current CPU.
if (!cb)
return 0;
-
- /*
- * This invokes the callback directly for now. In a later step we
- * convert that to use cpuhp_invoke_callback().
- */
- if (cpuhp_is_ap_state(state)) {
- /*
- * Note, that a function called on the AP is not
- * allowed to fail.
- */
- if (cpu_online(cpu))
- smp_call_function_single(cpu, cpuhp_on_cpu_cb, cb, 1);
- return 0;
- }
-
/*
* The non AP bound callbacks can fail on bringup. On teardown
* e.g. module removal we crash for now.
*/
- ret = cb(cpu);
+#ifdef CONFIG_SMP
+ if (cpuhp_is_ap_state(state))
+ ret = cpuhp_invoke_ap_callback(cpu, state, cb);
+ else
+ ret = cpuhp_invoke_callback(cpu, state, cb);
+#else
+ ret = cpuhp_invoke_callback(cpu, state, cb);
+#endif
BUG_ON(ret && !bringup);
return ret;
}
enum cpuhp_state i;
mutex_lock(&cpuhp_state_mutex);
- for (i = CPUHP_ONLINE_DYN; i <= CPUHP_ONLINE_DYN_END; i++) {
- if (cpuhp_bp_states[i].name)
+ for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) {
+ if (cpuhp_ap_states[i].name)
continue;
- cpuhp_bp_states[i].name = "Reserved";
+ cpuhp_ap_states[i].name = "Reserved";
mutex_unlock(&cpuhp_state_mutex);
return i;
}
get_online_cpus();
/* currently assignments for the ONLINE state are possible */
- if (state == CPUHP_ONLINE_DYN) {
+ if (state == CPUHP_AP_ONLINE_DYN) {
dyn_state = 1;
ret = cpuhp_reserve_state(state);
if (ret < 0)
projects / linux-2.6-block.git / blobdiff