#include <linux/lockdep.h>
#include <linux/tick.h>
#include <linux/irq.h>
+#include <linux/smpboot.h>
#include <trace/events/power.h>
#define CREATE_TRACE_POINTS
* cpuhp_cpu_state - Per cpu hotplug state storage
* @state: The current cpu state
* @target: The target state
+ * @thread: Pointer to the hotplug thread
+ * @should_run: Thread should execute
+ * @cb_stat: The state for a single callback (install/uninstall)
+ * @cb: Single callback function (install/uninstall)
+ * @result: Result of the operation
+ * @done: Signal completion to the issuer of the task
*/
struct cpuhp_cpu_state {
enum cpuhp_state state;
enum cpuhp_state target;
+#ifdef CONFIG_SMP
+ struct task_struct *thread;
+ bool should_run;
+ enum cpuhp_state cb_state;
+ int (*cb)(unsigned int cpu);
+ int result;
+ struct completion done;
+#endif
};
static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);
* @teardown: Teardown function of the step
* @skip_onerr: Do not invoke the functions on error rollback
* Will go away once the notifiers are gone
+ * @cant_stop: Bringup/teardown can't be stopped at this step
*/
struct cpuhp_step {
const char *name;
int (*startup)(unsigned int cpu);
int (*teardown)(unsigned int cpu);
bool skip_onerr;
+ bool cant_stop;
};
static DEFINE_MUTEX(cpuhp_state_mutex);
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;
+}
+
+/*
+ * Hotplug state machine related functions
+ */
+static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st,
+ struct cpuhp_step *steps)
+{
+ for (st->state++; st->state < st->target; st->state++) {
+ struct cpuhp_step *step = steps + st->state;
+
+ if (!step->skip_onerr)
+ cpuhp_invoke_callback(cpu, st->state, step->startup);
+ }
+}
+
+static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
+ struct cpuhp_step *steps, enum cpuhp_state target)
+{
+ enum cpuhp_state prev_state = st->state;
+ int ret = 0;
+
+ for (; st->state > target; st->state--) {
+ struct cpuhp_step *step = steps + st->state;
+
+ ret = cpuhp_invoke_callback(cpu, st->state, step->teardown);
+ if (ret) {
+ st->target = prev_state;
+ undo_cpu_down(cpu, st, steps);
+ break;
+ }
+ }
+ return ret;
+}
+
+static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st,
+ struct cpuhp_step *steps)
+{
+ for (st->state--; st->state > st->target; st->state--) {
+ struct cpuhp_step *step = steps + st->state;
+
+ if (!step->skip_onerr)
+ cpuhp_invoke_callback(cpu, st->state, step->teardown);
+ }
+}
+
+static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
+ struct cpuhp_step *steps, enum cpuhp_state target)
+{
+ enum cpuhp_state prev_state = st->state;
+ int ret = 0;
+
+ while (st->state < target) {
+ struct cpuhp_step *step;
+
+ st->state++;
+ step = steps + st->state;
+ ret = cpuhp_invoke_callback(cpu, st->state, step->startup);
+ if (ret) {
+ st->target = prev_state;
+ undo_cpu_up(cpu, st, steps);
+ break;
+ }
+ }
+ return ret;
+}
+
+/*
+ * The cpu hotplug threads manage the bringup and teardown of the cpus
+ */
+static void cpuhp_create(unsigned int cpu)
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+
+ init_completion(&st->done);
+}
+
+static int cpuhp_should_run(unsigned int cpu)
+{
+ struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+
+ return st->should_run;
+}
+
+/* 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_TEARDOWN_CPU);
+
+ return cpuhp_down_callbacks(cpu, st, cpuhp_ap_states, target);
+}
+
+/* Execute the online startup callbacks. Used to be CPU_ONLINE */
+static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st)
+{
+ return cpuhp_up_callbacks(cpu, st, cpuhp_ap_states, st->target);
+}
+
+/*
+ * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
+ * callbacks when a state gets [un]installed at runtime.
+ */
+static void cpuhp_thread_fun(unsigned int cpu)
+{
+ struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+ int ret = 0;
+
+ /*
+ * Paired with the mb() in cpuhp_kick_ap_work and
+ * cpuhp_invoke_ap_callback, so the work set is consistent visible.
+ */
+ smp_mb();
+ if (!st->should_run)
+ return;
+
+ st->should_run = false;
+
+ /* Single callback invocation for [un]install ? */
+ if (st->cb) {
+ if (st->cb_state < CPUHP_AP_ONLINE) {
+ local_irq_disable();
+ ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb);
+ local_irq_enable();
+ } else {
+ 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);
+ else if (st->state > st->target)
+ ret = cpuhp_ap_offline(cpu, st);
+ }
+ st->result = ret;
+ complete(&st->done);
+}
+
+/* Invoke a single callback on a remote cpu */
+static int cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state,
+ int (*cb)(unsigned int))
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+
+ if (!cpu_online(cpu))
+ return 0;
+
+ st->cb_state = state;
+ st->cb = cb;
+ /*
+ * Make sure the above stores are visible before should_run becomes
+ * true. Paired with the mb() above in cpuhp_thread_fun()
+ */
+ smp_mb();
+ st->should_run = true;
+ wake_up_process(st->thread);
+ wait_for_completion(&st->done);
+ return st->result;
+}
+
+/* Regular hotplug invocation of the AP hotplug thread */
+static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st)
+{
+ st->result = 0;
+ st->cb = NULL;
+ /*
+ * Make sure the above stores are visible before should_run becomes
+ * true. Paired with the mb() above in cpuhp_thread_fun()
+ */
+ 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 struct smp_hotplug_thread cpuhp_threads = {
+ .store = &cpuhp_state.thread,
+ .create = &cpuhp_create,
+ .thread_should_run = cpuhp_should_run,
+ .thread_fn = cpuhp_thread_fun,
+ .thread_comm = "cpuhp/%u",
+ .selfparking = true,
+};
+
+void __init cpuhp_threads_init(void)
+{
+ BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads));
+ kthread_unpark(this_cpu_read(cpuhp_state.thread));
}
#ifdef CONFIG_HOTPLUG_CPU
EXPORT_SYMBOL(register_cpu_notifier);
EXPORT_SYMBOL(__register_cpu_notifier);
-
void unregister_cpu_notifier(struct notifier_block *nb)
{
cpu_maps_update_begin();
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);
/*
*
* 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
#endif
#ifdef CONFIG_HOTPLUG_CPU
-static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
-{
- for (st->state++; st->state < st->target; st->state++) {
- struct cpuhp_step *step = cpuhp_bp_states + st->state;
-
- if (!step->skip_onerr)
- cpuhp_invoke_callback(cpu, st->state, step->startup);
- }
-}
/* Requires cpu_add_remove_lock to be held */
static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
if (num_online_cpus() == 1)
return -EBUSY;
- if (!cpu_online(cpu))
+ if (!cpu_present(cpu))
return -EINVAL;
cpu_hotplug_begin();
prev_state = st->state;
st->target = target;
- for (; st->state > st->target; st->state--) {
- struct cpuhp_step *step = cpuhp_bp_states + st->state;
+ /*
+ * 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;
- ret = cpuhp_invoke_callback(cpu, st->state, step->teardown);
- if (ret) {
- st->target = prev_state;
- undo_cpu_down(cpu, st);
- break;
- }
+ /*
+ * 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;
}
- hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE;
+ /*
+ * 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)
EXPORT_SYMBOL(cpu_down);
#endif /*CONFIG_HOTPLUG_CPU*/
-/*
- * Unpark per-CPU smpboot kthreads at CPU-online time.
- */
-static int smpboot_thread_call(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
-{
- int cpu = (long)hcpu;
-
- switch (action & ~CPU_TASKS_FROZEN) {
-
- case CPU_DOWN_FAILED:
- case CPU_ONLINE:
- smpboot_unpark_threads(cpu);
- break;
-
- default:
- break;
- }
-
- return NOTIFY_OK;
-}
-
-static struct notifier_block smpboot_thread_notifier = {
- .notifier_call = smpboot_thread_call,
- .priority = CPU_PRI_SMPBOOT,
-};
-
-void smpboot_thread_init(void)
-{
- register_cpu_notifier(&smpboot_thread_notifier);
-}
-
/**
* notify_cpu_starting(cpu) - call the CPU_STARTING notifiers
* @cpu: cpu that just started
}
}
-static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
+/*
+ * Called from the idle task. We need to set active here, so we can kick off
+ * 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.
+ */
+void cpuhp_online_idle(enum cpuhp_state state)
{
- for (st->state--; st->state > st->target; st->state--) {
- struct cpuhp_step *step = cpuhp_bp_states + st->state;
+ struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
+ unsigned int cpu = smp_processor_id();
- if (!step->skip_onerr)
- cpuhp_invoke_callback(cpu, st->state, step->teardown);
- }
+ /* 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 and the hotplug thread of this cpu */
+ stop_machine_unpark(cpu);
+ 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 */
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
struct task_struct *idle;
- int prev_state, ret = 0;
+ int ret = 0;
cpu_hotplug_begin();
- if (cpu_online(cpu) || !cpu_present(cpu)) {
+ if (!cpu_present(cpu)) {
ret = -EINVAL;
goto out;
}
- /* Let it fail before we try to bring the cpu up */
- idle = idle_thread_get(cpu);
- if (IS_ERR(idle)) {
- ret = PTR_ERR(idle);
+ /*
+ * The caller of do_cpu_up might have raced with another
+ * caller. Ignore it for now.
+ */
+ if (st->state >= target)
goto out;
+
+ if (st->state == CPUHP_OFFLINE) {
+ /* Let it fail before we try to bring the cpu up */
+ idle = idle_thread_get(cpu);
+ if (IS_ERR(idle)) {
+ ret = PTR_ERR(idle);
+ goto out;
+ }
}
cpuhp_tasks_frozen = tasks_frozen;
- prev_state = st->state;
st->target = target;
- while (st->state < st->target) {
- struct cpuhp_step *step;
-
- st->state++;
- step = cpuhp_bp_states + st->state;
- ret = cpuhp_invoke_callback(cpu, st->state, step->startup);
- if (ret) {
- st->target = prev_state;
- undo_cpu_up(cpu, st);
- break;
- }
+ /*
+ * 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();
return ret;
.name = "threads:create",
.startup = smpboot_create_threads,
.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,
.teardown = notify_dead,
.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,
- },
- [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,
.teardown = notify_dying,
.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,
},
};
+/* Sanity check for callbacks */
+static int cpuhp_cb_check(enum cpuhp_state state)
+{
+ if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE)
+ return -EINVAL;
+ return 0;
+}
+
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 sp + state;
}
+static void cpuhp_store_callbacks(enum cpuhp_state state,
+ const char *name,
+ int (*startup)(unsigned int cpu),
+ int (*teardown)(unsigned int cpu))
+{
+ /* (Un)Install the callbacks for further cpu hotplug operations */
+ struct cpuhp_step *sp;
+
+ mutex_lock(&cpuhp_state_mutex);
+ sp = cpuhp_get_step(state);
+ sp->startup = startup;
+ sp->teardown = teardown;
+ sp->name = name;
+ mutex_unlock(&cpuhp_state_mutex);
+}
+
+static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
+{
+ return cpuhp_get_step(state)->teardown;
+}
+
+/*
+ * Call the startup/teardown function for a step either on the AP or
+ * on the current CPU.
+ */
+static int cpuhp_issue_call(int cpu, enum cpuhp_state state,
+ int (*cb)(unsigned int), bool bringup)
+{
+ int ret;
+
+ if (!cb)
+ return 0;
+ /*
+ * The non AP bound callbacks can fail on bringup. On teardown
+ * e.g. module removal we crash for now.
+ */
+#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;
+}
+
+/*
+ * Called from __cpuhp_setup_state on a recoverable failure.
+ *
+ * Note: The teardown callbacks for rollback are not allowed to fail!
+ */
+static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state,
+ int (*teardown)(unsigned int cpu))
+{
+ int cpu;
+
+ if (!teardown)
+ return;
+
+ /* Roll back the already executed steps on the other cpus */
+ for_each_present_cpu(cpu) {
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+ int cpustate = st->state;
+
+ if (cpu >= failedcpu)
+ break;
+
+ /* Did we invoke the startup call on that cpu ? */
+ if (cpustate >= state)
+ cpuhp_issue_call(cpu, state, teardown, false);
+ }
+}
+
+/*
+ * Returns a free for dynamic slot assignment of the Online state. The states
+ * are protected by the cpuhp_slot_states mutex and an empty slot is identified
+ * by having no name assigned.
+ */
+static int cpuhp_reserve_state(enum cpuhp_state state)
+{
+ enum cpuhp_state i;
+
+ mutex_lock(&cpuhp_state_mutex);
+ for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) {
+ if (cpuhp_ap_states[i].name)
+ continue;
+
+ cpuhp_ap_states[i].name = "Reserved";
+ mutex_unlock(&cpuhp_state_mutex);
+ return i;
+ }
+ mutex_unlock(&cpuhp_state_mutex);
+ WARN(1, "No more dynamic states available for CPU hotplug\n");
+ return -ENOSPC;
+}
+
+/**
+ * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state
+ * @state: The state to setup
+ * @invoke: If true, the startup function is invoked for cpus where
+ * cpu state >= @state
+ * @startup: startup callback function
+ * @teardown: teardown callback function
+ *
+ * Returns 0 if successful, otherwise a proper error code
+ */
+int __cpuhp_setup_state(enum cpuhp_state state,
+ const char *name, bool invoke,
+ int (*startup)(unsigned int cpu),
+ int (*teardown)(unsigned int cpu))
+{
+ int cpu, ret = 0;
+ int dyn_state = 0;
+
+ if (cpuhp_cb_check(state) || !name)
+ return -EINVAL;
+
+ get_online_cpus();
+
+ /* currently assignments for the ONLINE state are possible */
+ if (state == CPUHP_AP_ONLINE_DYN) {
+ dyn_state = 1;
+ ret = cpuhp_reserve_state(state);
+ if (ret < 0)
+ goto out;
+ state = ret;
+ }
+
+ cpuhp_store_callbacks(state, name, startup, teardown);
+
+ if (!invoke || !startup)
+ goto out;
+
+ /*
+ * Try to call the startup callback for each present cpu
+ * depending on the hotplug state of the cpu.
+ */
+ for_each_present_cpu(cpu) {
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+ int cpustate = st->state;
+
+ if (cpustate < state)
+ continue;
+
+ ret = cpuhp_issue_call(cpu, state, startup, true);
+ if (ret) {
+ cpuhp_rollback_install(cpu, state, teardown);
+ cpuhp_store_callbacks(state, NULL, NULL, NULL);
+ goto out;
+ }
+ }
+out:
+ put_online_cpus();
+ if (!ret && dyn_state)
+ return state;
+ return ret;
+}
+EXPORT_SYMBOL(__cpuhp_setup_state);
+
+/**
+ * __cpuhp_remove_state - Remove the callbacks for an hotplug machine state
+ * @state: The state to remove
+ * @invoke: If true, the teardown function is invoked for cpus where
+ * cpu state >= @state
+ *
+ * The teardown callback is currently not allowed to fail. Think
+ * about module removal!
+ */
+void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
+{
+ int (*teardown)(unsigned int cpu) = cpuhp_get_teardown_cb(state);
+ int cpu;
+
+ BUG_ON(cpuhp_cb_check(state));
+
+ get_online_cpus();
+
+ if (!invoke || !teardown)
+ goto remove;
+
+ /*
+ * Call the teardown callback for each present cpu depending
+ * on the hotplug state of the cpu. This function is not
+ * allowed to fail currently!
+ */
+ for_each_present_cpu(cpu) {
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
+ int cpustate = st->state;
+
+ if (cpustate >= state)
+ cpuhp_issue_call(cpu, state, teardown, false);
+ }
+remove:
+ cpuhp_store_callbacks(state, NULL, NULL, NULL);
+ put_online_cpus();
+}
+EXPORT_SYMBOL(__cpuhp_remove_state);
+
#if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
static ssize_t show_cpuhp_state(struct device *dev,
struct device_attribute *attr, char *buf)
}
static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL);
+static ssize_t write_cpuhp_target(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
+ struct cpuhp_step *sp;
+ int target, ret;
+
+ ret = kstrtoint(buf, 10, &target);
+ if (ret)
+ return ret;
+
+#ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL
+ if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE)
+ return -EINVAL;
+#else
+ if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE)
+ return -EINVAL;
+#endif
+
+ ret = lock_device_hotplug_sysfs();
+ if (ret)
+ return ret;
+
+ mutex_lock(&cpuhp_state_mutex);
+ sp = cpuhp_get_step(target);
+ ret = !sp->name || sp->cant_stop ? -EINVAL : 0;
+ mutex_unlock(&cpuhp_state_mutex);
+ if (ret)
+ return ret;
+
+ if (st->state < target)
+ ret = do_cpu_up(dev->id, target);
+ else
+ ret = do_cpu_down(dev->id, target);
+
+ unlock_device_hotplug();
+ return ret ? ret : count;
+}
+
static ssize_t show_cpuhp_target(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", st->target);
}
-static DEVICE_ATTR(target, 0444, show_cpuhp_target, NULL);
+static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target);
static struct attribute *cpuhp_cpu_attrs[] = {
&dev_attr_state.attr,
int i;
mutex_lock(&cpuhp_state_mutex);
- for (i = 0; i <= CPUHP_ONLINE; i++) {
+ for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) {
struct cpuhp_step *sp = cpuhp_get_step(i);
if (sp->name) {
projects / deliverable / linux.git / blobdiff