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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
1832 lines
44 KiB
C
1832 lines
44 KiB
C
/* CPU control.
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* (C) 2001, 2002, 2003, 2004 Rusty Russell
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*
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* This code is licenced under the GPL.
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*/
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#include <linux/proc_fs.h>
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#include <linux/smp.h>
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#include <linux/init.h>
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#include <linux/notifier.h>
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#include <linux/sched/signal.h>
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#include <linux/sched/hotplug.h>
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#include <linux/sched/task.h>
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#include <linux/unistd.h>
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#include <linux/cpu.h>
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#include <linux/oom.h>
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#include <linux/rcupdate.h>
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#include <linux/export.h>
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#include <linux/bug.h>
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#include <linux/kthread.h>
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#include <linux/stop_machine.h>
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#include <linux/mutex.h>
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#include <linux/gfp.h>
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#include <linux/suspend.h>
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#include <linux/lockdep.h>
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#include <linux/tick.h>
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#include <linux/irq.h>
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#include <linux/smpboot.h>
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#include <linux/relay.h>
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#include <linux/slab.h>
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#include <trace/events/power.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/cpuhp.h>
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#include "smpboot.h"
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/**
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* cpuhp_cpu_state - Per cpu hotplug state storage
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* @state: The current cpu state
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* @target: The target state
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* @thread: Pointer to the hotplug thread
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* @should_run: Thread should execute
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* @rollback: Perform a rollback
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* @single: Single callback invocation
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* @bringup: Single callback bringup or teardown selector
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* @cb_state: The state for a single callback (install/uninstall)
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* @result: Result of the operation
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* @done: Signal completion to the issuer of the task
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*/
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struct cpuhp_cpu_state {
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enum cpuhp_state state;
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enum cpuhp_state target;
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#ifdef CONFIG_SMP
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struct task_struct *thread;
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bool should_run;
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bool rollback;
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bool single;
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bool bringup;
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struct hlist_node *node;
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enum cpuhp_state cb_state;
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int result;
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struct completion done;
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#endif
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};
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static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);
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/**
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* cpuhp_step - Hotplug state machine step
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* @name: Name of the step
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* @startup: Startup function of the step
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* @teardown: Teardown function of the step
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* @skip_onerr: Do not invoke the functions on error rollback
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* Will go away once the notifiers are gone
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* @cant_stop: Bringup/teardown can't be stopped at this step
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*/
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struct cpuhp_step {
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const char *name;
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union {
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int (*single)(unsigned int cpu);
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int (*multi)(unsigned int cpu,
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struct hlist_node *node);
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} startup;
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union {
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int (*single)(unsigned int cpu);
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int (*multi)(unsigned int cpu,
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struct hlist_node *node);
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} teardown;
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struct hlist_head list;
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bool skip_onerr;
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bool cant_stop;
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bool multi_instance;
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};
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static DEFINE_MUTEX(cpuhp_state_mutex);
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static struct cpuhp_step cpuhp_bp_states[];
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static struct cpuhp_step cpuhp_ap_states[];
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static bool cpuhp_is_ap_state(enum cpuhp_state state)
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{
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/*
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* The extra check for CPUHP_TEARDOWN_CPU is only for documentation
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* purposes as that state is handled explicitly in cpu_down.
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*/
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return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
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}
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static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
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{
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struct cpuhp_step *sp;
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sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states;
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return sp + state;
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}
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/**
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* cpuhp_invoke_callback _ Invoke the callbacks for a given state
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* @cpu: The cpu for which the callback should be invoked
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* @step: The step in the state machine
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* @bringup: True if the bringup callback should be invoked
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*
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* Called from cpu hotplug and from the state register machinery.
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*/
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static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
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bool bringup, struct hlist_node *node)
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{
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struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
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struct cpuhp_step *step = cpuhp_get_step(state);
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int (*cbm)(unsigned int cpu, struct hlist_node *node);
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int (*cb)(unsigned int cpu);
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int ret, cnt;
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if (!step->multi_instance) {
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cb = bringup ? step->startup.single : step->teardown.single;
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if (!cb)
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return 0;
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trace_cpuhp_enter(cpu, st->target, state, cb);
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ret = cb(cpu);
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trace_cpuhp_exit(cpu, st->state, state, ret);
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return ret;
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}
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cbm = bringup ? step->startup.multi : step->teardown.multi;
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if (!cbm)
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return 0;
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/* Single invocation for instance add/remove */
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if (node) {
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trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
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ret = cbm(cpu, node);
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trace_cpuhp_exit(cpu, st->state, state, ret);
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return ret;
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}
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/* State transition. Invoke on all instances */
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cnt = 0;
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hlist_for_each(node, &step->list) {
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trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
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ret = cbm(cpu, node);
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trace_cpuhp_exit(cpu, st->state, state, ret);
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if (ret)
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goto err;
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cnt++;
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}
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return 0;
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err:
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/* Rollback the instances if one failed */
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cbm = !bringup ? step->startup.multi : step->teardown.multi;
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if (!cbm)
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return ret;
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hlist_for_each(node, &step->list) {
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if (!cnt--)
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break;
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cbm(cpu, node);
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}
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return ret;
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}
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#ifdef CONFIG_SMP
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/* Serializes the updates to cpu_online_mask, cpu_present_mask */
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static DEFINE_MUTEX(cpu_add_remove_lock);
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bool cpuhp_tasks_frozen;
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EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
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/*
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* The following two APIs (cpu_maps_update_begin/done) must be used when
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* attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
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*/
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void cpu_maps_update_begin(void)
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{
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mutex_lock(&cpu_add_remove_lock);
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}
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void cpu_maps_update_done(void)
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{
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mutex_unlock(&cpu_add_remove_lock);
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}
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/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
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* Should always be manipulated under cpu_add_remove_lock
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*/
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static int cpu_hotplug_disabled;
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#ifdef CONFIG_HOTPLUG_CPU
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static struct {
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struct task_struct *active_writer;
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/* wait queue to wake up the active_writer */
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wait_queue_head_t wq;
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/* verifies that no writer will get active while readers are active */
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struct mutex lock;
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/*
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* Also blocks the new readers during
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* an ongoing cpu hotplug operation.
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*/
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atomic_t refcount;
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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struct lockdep_map dep_map;
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#endif
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} cpu_hotplug = {
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.active_writer = NULL,
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.wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
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.lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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.dep_map = STATIC_LOCKDEP_MAP_INIT("cpu_hotplug.dep_map", &cpu_hotplug.dep_map),
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#endif
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};
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/* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
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#define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
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#define cpuhp_lock_acquire_tryread() \
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lock_map_acquire_tryread(&cpu_hotplug.dep_map)
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#define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
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#define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
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void get_online_cpus(void)
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{
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might_sleep();
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if (cpu_hotplug.active_writer == current)
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return;
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cpuhp_lock_acquire_read();
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mutex_lock(&cpu_hotplug.lock);
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atomic_inc(&cpu_hotplug.refcount);
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mutex_unlock(&cpu_hotplug.lock);
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}
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EXPORT_SYMBOL_GPL(get_online_cpus);
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void put_online_cpus(void)
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{
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int refcount;
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if (cpu_hotplug.active_writer == current)
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return;
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refcount = atomic_dec_return(&cpu_hotplug.refcount);
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if (WARN_ON(refcount < 0)) /* try to fix things up */
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atomic_inc(&cpu_hotplug.refcount);
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if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq))
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wake_up(&cpu_hotplug.wq);
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cpuhp_lock_release();
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}
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EXPORT_SYMBOL_GPL(put_online_cpus);
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/*
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* This ensures that the hotplug operation can begin only when the
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* refcount goes to zero.
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*
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* Note that during a cpu-hotplug operation, the new readers, if any,
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* will be blocked by the cpu_hotplug.lock
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*
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* Since cpu_hotplug_begin() is always called after invoking
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* cpu_maps_update_begin(), we can be sure that only one writer is active.
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*
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* Note that theoretically, there is a possibility of a livelock:
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* - Refcount goes to zero, last reader wakes up the sleeping
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* writer.
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* - Last reader unlocks the cpu_hotplug.lock.
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* - A new reader arrives at this moment, bumps up the refcount.
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* - The writer acquires the cpu_hotplug.lock finds the refcount
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* non zero and goes to sleep again.
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*
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* However, this is very difficult to achieve in practice since
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* get_online_cpus() not an api which is called all that often.
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*
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*/
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void cpu_hotplug_begin(void)
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{
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DEFINE_WAIT(wait);
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cpu_hotplug.active_writer = current;
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cpuhp_lock_acquire();
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for (;;) {
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mutex_lock(&cpu_hotplug.lock);
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prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE);
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if (likely(!atomic_read(&cpu_hotplug.refcount)))
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break;
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mutex_unlock(&cpu_hotplug.lock);
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schedule();
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}
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finish_wait(&cpu_hotplug.wq, &wait);
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}
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void cpu_hotplug_done(void)
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{
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cpu_hotplug.active_writer = NULL;
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mutex_unlock(&cpu_hotplug.lock);
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cpuhp_lock_release();
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}
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/*
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* Wait for currently running CPU hotplug operations to complete (if any) and
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* disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
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* the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
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* hotplug path before performing hotplug operations. So acquiring that lock
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* guarantees mutual exclusion from any currently running hotplug operations.
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*/
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void cpu_hotplug_disable(void)
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{
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cpu_maps_update_begin();
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cpu_hotplug_disabled++;
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cpu_maps_update_done();
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}
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EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
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static void __cpu_hotplug_enable(void)
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{
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if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n"))
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return;
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cpu_hotplug_disabled--;
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}
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void cpu_hotplug_enable(void)
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{
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cpu_maps_update_begin();
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__cpu_hotplug_enable();
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cpu_maps_update_done();
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}
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EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
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#endif /* CONFIG_HOTPLUG_CPU */
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/* Notifier wrappers for transitioning to state machine */
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static int bringup_wait_for_ap(unsigned int cpu)
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{
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struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
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wait_for_completion(&st->done);
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return st->result;
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}
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static int bringup_cpu(unsigned int cpu)
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{
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struct task_struct *idle = idle_thread_get(cpu);
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int ret;
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/*
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* Some architectures have to walk the irq descriptors to
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* setup the vector space for the cpu which comes online.
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* Prevent irq alloc/free across the bringup.
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*/
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irq_lock_sparse();
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/* Arch-specific enabling code. */
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ret = __cpu_up(cpu, idle);
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irq_unlock_sparse();
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if (ret)
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return ret;
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ret = bringup_wait_for_ap(cpu);
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BUG_ON(!cpu_online(cpu));
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return ret;
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}
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/*
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* Hotplug state machine related functions
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*/
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static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
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{
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for (st->state++; st->state < st->target; st->state++) {
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struct cpuhp_step *step = cpuhp_get_step(st->state);
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if (!step->skip_onerr)
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cpuhp_invoke_callback(cpu, st->state, true, NULL);
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}
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}
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static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
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enum cpuhp_state target)
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{
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enum cpuhp_state prev_state = st->state;
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int ret = 0;
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for (; st->state > target; st->state--) {
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ret = cpuhp_invoke_callback(cpu, st->state, false, NULL);
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if (ret) {
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st->target = prev_state;
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undo_cpu_down(cpu, st);
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break;
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}
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}
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return ret;
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}
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static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
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{
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for (st->state--; st->state > st->target; st->state--) {
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struct cpuhp_step *step = cpuhp_get_step(st->state);
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if (!step->skip_onerr)
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cpuhp_invoke_callback(cpu, st->state, false, NULL);
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}
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}
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static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
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enum cpuhp_state target)
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{
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enum cpuhp_state prev_state = st->state;
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int ret = 0;
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while (st->state < target) {
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st->state++;
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ret = cpuhp_invoke_callback(cpu, st->state, true, NULL);
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if (ret) {
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st->target = prev_state;
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undo_cpu_up(cpu, st);
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break;
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}
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}
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return ret;
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}
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/*
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* The cpu hotplug threads manage the bringup and teardown of the cpus
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*/
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static void cpuhp_create(unsigned int cpu)
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{
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struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
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init_completion(&st->done);
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}
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static int cpuhp_should_run(unsigned int cpu)
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{
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struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
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return st->should_run;
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}
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/* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */
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static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st)
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{
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enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU);
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return cpuhp_down_callbacks(cpu, st, target);
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}
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/* Execute the online startup callbacks. Used to be CPU_ONLINE */
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static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st)
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{
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return cpuhp_up_callbacks(cpu, st, st->target);
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}
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/*
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* Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
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* callbacks when a state gets [un]installed at runtime.
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*/
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static void cpuhp_thread_fun(unsigned int cpu)
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{
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struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
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int ret = 0;
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/*
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* Paired with the mb() in cpuhp_kick_ap_work and
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* cpuhp_invoke_ap_callback, so the work set is consistent visible.
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*/
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smp_mb();
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if (!st->should_run)
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return;
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st->should_run = false;
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/* Single callback invocation for [un]install ? */
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if (st->single) {
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if (st->cb_state < CPUHP_AP_ONLINE) {
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local_irq_disable();
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ret = cpuhp_invoke_callback(cpu, st->cb_state,
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st->bringup, st->node);
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local_irq_enable();
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} else {
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ret = cpuhp_invoke_callback(cpu, st->cb_state,
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st->bringup, st->node);
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}
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} else if (st->rollback) {
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BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
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undo_cpu_down(cpu, st);
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st->rollback = false;
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} else {
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/* Cannot happen .... */
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BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
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/* Regular hotplug work */
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if (st->state < st->target)
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ret = cpuhp_ap_online(cpu, st);
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else if (st->state > st->target)
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ret = cpuhp_ap_offline(cpu, st);
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}
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st->result = ret;
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complete(&st->done);
|
|
}
|
|
|
|
/* Invoke a single callback on a remote cpu */
|
|
static int
|
|
cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup,
|
|
struct hlist_node *node)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
|
|
if (!cpu_online(cpu))
|
|
return 0;
|
|
|
|
/*
|
|
* If we are up and running, use the hotplug thread. For early calls
|
|
* we invoke the thread function directly.
|
|
*/
|
|
if (!st->thread)
|
|
return cpuhp_invoke_callback(cpu, state, bringup, node);
|
|
|
|
st->cb_state = state;
|
|
st->single = true;
|
|
st->bringup = bringup;
|
|
st->node = node;
|
|
|
|
/*
|
|
* 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->single = false;
|
|
/*
|
|
* 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
|
|
/**
|
|
* clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
|
|
* @cpu: a CPU id
|
|
*
|
|
* This function walks all processes, finds a valid mm struct for each one and
|
|
* then clears a corresponding bit in mm's cpumask. While this all sounds
|
|
* trivial, there are various non-obvious corner cases, which this function
|
|
* tries to solve in a safe manner.
|
|
*
|
|
* Also note that the function uses a somewhat relaxed locking scheme, so it may
|
|
* be called only for an already offlined CPU.
|
|
*/
|
|
void clear_tasks_mm_cpumask(int cpu)
|
|
{
|
|
struct task_struct *p;
|
|
|
|
/*
|
|
* This function is called after the cpu is taken down and marked
|
|
* offline, so its not like new tasks will ever get this cpu set in
|
|
* their mm mask. -- Peter Zijlstra
|
|
* Thus, we may use rcu_read_lock() here, instead of grabbing
|
|
* full-fledged tasklist_lock.
|
|
*/
|
|
WARN_ON(cpu_online(cpu));
|
|
rcu_read_lock();
|
|
for_each_process(p) {
|
|
struct task_struct *t;
|
|
|
|
/*
|
|
* Main thread might exit, but other threads may still have
|
|
* a valid mm. Find one.
|
|
*/
|
|
t = find_lock_task_mm(p);
|
|
if (!t)
|
|
continue;
|
|
cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
|
|
task_unlock(t);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
static inline void check_for_tasks(int dead_cpu)
|
|
{
|
|
struct task_struct *g, *p;
|
|
|
|
read_lock(&tasklist_lock);
|
|
for_each_process_thread(g, p) {
|
|
if (!p->on_rq)
|
|
continue;
|
|
/*
|
|
* We do the check with unlocked task_rq(p)->lock.
|
|
* Order the reading to do not warn about a task,
|
|
* which was running on this cpu in the past, and
|
|
* it's just been woken on another cpu.
|
|
*/
|
|
rmb();
|
|
if (task_cpu(p) != dead_cpu)
|
|
continue;
|
|
|
|
pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
|
|
p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
|
|
}
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
/* Take this CPU down. */
|
|
static int take_cpu_down(void *_param)
|
|
{
|
|
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
|
|
enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
|
|
int err, cpu = smp_processor_id();
|
|
|
|
/* Ensure this CPU doesn't handle any more interrupts. */
|
|
err = __cpu_disable();
|
|
if (err < 0)
|
|
return err;
|
|
|
|
/*
|
|
* We get here while we are in CPUHP_TEARDOWN_CPU state and we must not
|
|
* do this step again.
|
|
*/
|
|
WARN_ON(st->state != CPUHP_TEARDOWN_CPU);
|
|
st->state--;
|
|
/* Invoke the former CPU_DYING callbacks */
|
|
for (; st->state > target; st->state--)
|
|
cpuhp_invoke_callback(cpu, st->state, false, NULL);
|
|
|
|
/* Give up timekeeping duties */
|
|
tick_handover_do_timer();
|
|
/* Park the stopper thread */
|
|
stop_machine_park(cpu);
|
|
return 0;
|
|
}
|
|
|
|
static int takedown_cpu(unsigned int cpu)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
int err;
|
|
|
|
/* 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.
|
|
*/
|
|
irq_lock_sparse();
|
|
|
|
/*
|
|
* So now all preempt/rcu users must observe !cpu_active().
|
|
*/
|
|
err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
|
|
if (err) {
|
|
/* CPU refused to die */
|
|
irq_unlock_sparse();
|
|
/* Unpark the hotplug thread so we can rollback there */
|
|
kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread);
|
|
return err;
|
|
}
|
|
BUG_ON(cpu_online(cpu));
|
|
|
|
/*
|
|
* The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all
|
|
* runnable tasks from the cpu, there's only the idle task left now
|
|
* that the migration thread is done doing the stop_machine thing.
|
|
*
|
|
* Wait for the stop thread to go away.
|
|
*/
|
|
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();
|
|
|
|
hotplug_cpu__broadcast_tick_pull(cpu);
|
|
/* This actually kills the CPU. */
|
|
__cpu_die(cpu);
|
|
|
|
tick_cleanup_dead_cpu(cpu);
|
|
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 takedown_cpu NULL
|
|
#endif
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
/* Requires cpu_add_remove_lock to be held */
|
|
static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
|
|
enum cpuhp_state target)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
int prev_state, ret = 0;
|
|
|
|
if (num_online_cpus() == 1)
|
|
return -EBUSY;
|
|
|
|
if (!cpu_present(cpu))
|
|
return -EINVAL;
|
|
|
|
cpu_hotplug_begin();
|
|
|
|
cpuhp_tasks_frozen = tasks_frozen;
|
|
|
|
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, target);
|
|
if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) {
|
|
st->target = prev_state;
|
|
st->rollback = true;
|
|
cpuhp_kick_ap_work(cpu);
|
|
}
|
|
|
|
out:
|
|
cpu_hotplug_done();
|
|
return ret;
|
|
}
|
|
|
|
static int do_cpu_down(unsigned int cpu, enum cpuhp_state target)
|
|
{
|
|
int err;
|
|
|
|
cpu_maps_update_begin();
|
|
|
|
if (cpu_hotplug_disabled) {
|
|
err = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
err = _cpu_down(cpu, 0, target);
|
|
|
|
out:
|
|
cpu_maps_update_done();
|
|
return err;
|
|
}
|
|
int cpu_down(unsigned int cpu)
|
|
{
|
|
return do_cpu_down(cpu, CPUHP_OFFLINE);
|
|
}
|
|
EXPORT_SYMBOL(cpu_down);
|
|
#endif /*CONFIG_HOTPLUG_CPU*/
|
|
|
|
/**
|
|
* notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
|
|
* @cpu: cpu that just started
|
|
*
|
|
* 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)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
|
|
|
|
rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
|
|
while (st->state < target) {
|
|
st->state++;
|
|
cpuhp_invoke_callback(cpu, st->state, true, NULL);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
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;
|
|
|
|
/* 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 */
|
|
static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
struct task_struct *idle;
|
|
int ret = 0;
|
|
|
|
cpu_hotplug_begin();
|
|
|
|
if (!cpu_present(cpu)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
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, target);
|
|
out:
|
|
cpu_hotplug_done();
|
|
return ret;
|
|
}
|
|
|
|
static int do_cpu_up(unsigned int cpu, enum cpuhp_state target)
|
|
{
|
|
int err = 0;
|
|
|
|
if (!cpu_possible(cpu)) {
|
|
pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
|
|
cpu);
|
|
#if defined(CONFIG_IA64)
|
|
pr_err("please check additional_cpus= boot parameter\n");
|
|
#endif
|
|
return -EINVAL;
|
|
}
|
|
|
|
err = try_online_node(cpu_to_node(cpu));
|
|
if (err)
|
|
return err;
|
|
|
|
cpu_maps_update_begin();
|
|
|
|
if (cpu_hotplug_disabled) {
|
|
err = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
err = _cpu_up(cpu, 0, target);
|
|
out:
|
|
cpu_maps_update_done();
|
|
return err;
|
|
}
|
|
|
|
int cpu_up(unsigned int cpu)
|
|
{
|
|
return do_cpu_up(cpu, CPUHP_ONLINE);
|
|
}
|
|
EXPORT_SYMBOL_GPL(cpu_up);
|
|
|
|
#ifdef CONFIG_PM_SLEEP_SMP
|
|
static cpumask_var_t frozen_cpus;
|
|
|
|
int freeze_secondary_cpus(int primary)
|
|
{
|
|
int cpu, error = 0;
|
|
|
|
cpu_maps_update_begin();
|
|
if (!cpu_online(primary))
|
|
primary = cpumask_first(cpu_online_mask);
|
|
/*
|
|
* We take down all of the non-boot CPUs in one shot to avoid races
|
|
* with the userspace trying to use the CPU hotplug at the same time
|
|
*/
|
|
cpumask_clear(frozen_cpus);
|
|
|
|
pr_info("Disabling non-boot CPUs ...\n");
|
|
for_each_online_cpu(cpu) {
|
|
if (cpu == primary)
|
|
continue;
|
|
trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
|
|
error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
|
|
trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
|
|
if (!error)
|
|
cpumask_set_cpu(cpu, frozen_cpus);
|
|
else {
|
|
pr_err("Error taking CPU%d down: %d\n", cpu, error);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!error)
|
|
BUG_ON(num_online_cpus() > 1);
|
|
else
|
|
pr_err("Non-boot CPUs are not disabled\n");
|
|
|
|
/*
|
|
* Make sure the CPUs won't be enabled by someone else. We need to do
|
|
* this even in case of failure as all disable_nonboot_cpus() users are
|
|
* supposed to do enable_nonboot_cpus() on the failure path.
|
|
*/
|
|
cpu_hotplug_disabled++;
|
|
|
|
cpu_maps_update_done();
|
|
return error;
|
|
}
|
|
|
|
void __weak arch_enable_nonboot_cpus_begin(void)
|
|
{
|
|
}
|
|
|
|
void __weak arch_enable_nonboot_cpus_end(void)
|
|
{
|
|
}
|
|
|
|
void enable_nonboot_cpus(void)
|
|
{
|
|
int cpu, error;
|
|
|
|
/* Allow everyone to use the CPU hotplug again */
|
|
cpu_maps_update_begin();
|
|
__cpu_hotplug_enable();
|
|
if (cpumask_empty(frozen_cpus))
|
|
goto out;
|
|
|
|
pr_info("Enabling non-boot CPUs ...\n");
|
|
|
|
arch_enable_nonboot_cpus_begin();
|
|
|
|
for_each_cpu(cpu, frozen_cpus) {
|
|
trace_suspend_resume(TPS("CPU_ON"), cpu, true);
|
|
error = _cpu_up(cpu, 1, CPUHP_ONLINE);
|
|
trace_suspend_resume(TPS("CPU_ON"), cpu, false);
|
|
if (!error) {
|
|
pr_info("CPU%d is up\n", cpu);
|
|
continue;
|
|
}
|
|
pr_warn("Error taking CPU%d up: %d\n", cpu, error);
|
|
}
|
|
|
|
arch_enable_nonboot_cpus_end();
|
|
|
|
cpumask_clear(frozen_cpus);
|
|
out:
|
|
cpu_maps_update_done();
|
|
}
|
|
|
|
static int __init alloc_frozen_cpus(void)
|
|
{
|
|
if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
core_initcall(alloc_frozen_cpus);
|
|
|
|
/*
|
|
* When callbacks for CPU hotplug notifications are being executed, we must
|
|
* ensure that the state of the system with respect to the tasks being frozen
|
|
* or not, as reported by the notification, remains unchanged *throughout the
|
|
* duration* of the execution of the callbacks.
|
|
* Hence we need to prevent the freezer from racing with regular CPU hotplug.
|
|
*
|
|
* This synchronization is implemented by mutually excluding regular CPU
|
|
* hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
|
|
* Hibernate notifications.
|
|
*/
|
|
static int
|
|
cpu_hotplug_pm_callback(struct notifier_block *nb,
|
|
unsigned long action, void *ptr)
|
|
{
|
|
switch (action) {
|
|
|
|
case PM_SUSPEND_PREPARE:
|
|
case PM_HIBERNATION_PREPARE:
|
|
cpu_hotplug_disable();
|
|
break;
|
|
|
|
case PM_POST_SUSPEND:
|
|
case PM_POST_HIBERNATION:
|
|
cpu_hotplug_enable();
|
|
break;
|
|
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
|
|
static int __init cpu_hotplug_pm_sync_init(void)
|
|
{
|
|
/*
|
|
* cpu_hotplug_pm_callback has higher priority than x86
|
|
* bsp_pm_callback which depends on cpu_hotplug_pm_callback
|
|
* to disable cpu hotplug to avoid cpu hotplug race.
|
|
*/
|
|
pm_notifier(cpu_hotplug_pm_callback, 0);
|
|
return 0;
|
|
}
|
|
core_initcall(cpu_hotplug_pm_sync_init);
|
|
|
|
#endif /* CONFIG_PM_SLEEP_SMP */
|
|
|
|
int __boot_cpu_id;
|
|
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/* Boot processor state steps */
|
|
static struct cpuhp_step cpuhp_bp_states[] = {
|
|
[CPUHP_OFFLINE] = {
|
|
.name = "offline",
|
|
.startup.single = NULL,
|
|
.teardown.single = NULL,
|
|
},
|
|
#ifdef CONFIG_SMP
|
|
[CPUHP_CREATE_THREADS]= {
|
|
.name = "threads:prepare",
|
|
.startup.single = smpboot_create_threads,
|
|
.teardown.single = NULL,
|
|
.cant_stop = true,
|
|
},
|
|
[CPUHP_PERF_PREPARE] = {
|
|
.name = "perf:prepare",
|
|
.startup.single = perf_event_init_cpu,
|
|
.teardown.single = perf_event_exit_cpu,
|
|
},
|
|
[CPUHP_WORKQUEUE_PREP] = {
|
|
.name = "workqueue:prepare",
|
|
.startup.single = workqueue_prepare_cpu,
|
|
.teardown.single = NULL,
|
|
},
|
|
[CPUHP_HRTIMERS_PREPARE] = {
|
|
.name = "hrtimers:prepare",
|
|
.startup.single = hrtimers_prepare_cpu,
|
|
.teardown.single = hrtimers_dead_cpu,
|
|
},
|
|
[CPUHP_SMPCFD_PREPARE] = {
|
|
.name = "smpcfd:prepare",
|
|
.startup.single = smpcfd_prepare_cpu,
|
|
.teardown.single = smpcfd_dead_cpu,
|
|
},
|
|
[CPUHP_RELAY_PREPARE] = {
|
|
.name = "relay:prepare",
|
|
.startup.single = relay_prepare_cpu,
|
|
.teardown.single = NULL,
|
|
},
|
|
[CPUHP_SLAB_PREPARE] = {
|
|
.name = "slab:prepare",
|
|
.startup.single = slab_prepare_cpu,
|
|
.teardown.single = slab_dead_cpu,
|
|
},
|
|
[CPUHP_RCUTREE_PREP] = {
|
|
.name = "RCU/tree:prepare",
|
|
.startup.single = rcutree_prepare_cpu,
|
|
.teardown.single = rcutree_dead_cpu,
|
|
},
|
|
/*
|
|
* On the tear-down path, timers_dead_cpu() must be invoked
|
|
* before blk_mq_queue_reinit_notify() from notify_dead(),
|
|
* otherwise a RCU stall occurs.
|
|
*/
|
|
[CPUHP_TIMERS_DEAD] = {
|
|
.name = "timers:dead",
|
|
.startup.single = NULL,
|
|
.teardown.single = timers_dead_cpu,
|
|
},
|
|
/* Kicks the plugged cpu into life */
|
|
[CPUHP_BRINGUP_CPU] = {
|
|
.name = "cpu:bringup",
|
|
.startup.single = bringup_cpu,
|
|
.teardown.single = NULL,
|
|
.cant_stop = true,
|
|
},
|
|
[CPUHP_AP_SMPCFD_DYING] = {
|
|
.name = "smpcfd:dying",
|
|
.startup.single = NULL,
|
|
.teardown.single = smpcfd_dying_cpu,
|
|
},
|
|
/*
|
|
* Handled on controll processor until the plugged processor manages
|
|
* this itself.
|
|
*/
|
|
[CPUHP_TEARDOWN_CPU] = {
|
|
.name = "cpu:teardown",
|
|
.startup.single = NULL,
|
|
.teardown.single = takedown_cpu,
|
|
.cant_stop = true,
|
|
},
|
|
#else
|
|
[CPUHP_BRINGUP_CPU] = { },
|
|
#endif
|
|
};
|
|
|
|
/* 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,
|
|
},
|
|
/* First state is scheduler control. Interrupts are disabled */
|
|
[CPUHP_AP_SCHED_STARTING] = {
|
|
.name = "sched:starting",
|
|
.startup.single = sched_cpu_starting,
|
|
.teardown.single = sched_cpu_dying,
|
|
},
|
|
[CPUHP_AP_RCUTREE_DYING] = {
|
|
.name = "RCU/tree:dying",
|
|
.startup.single = NULL,
|
|
.teardown.single = rcutree_dying_cpu,
|
|
},
|
|
/* 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:online",
|
|
.startup.single = smpboot_unpark_threads,
|
|
.teardown.single = NULL,
|
|
},
|
|
[CPUHP_AP_PERF_ONLINE] = {
|
|
.name = "perf:online",
|
|
.startup.single = perf_event_init_cpu,
|
|
.teardown.single = perf_event_exit_cpu,
|
|
},
|
|
[CPUHP_AP_WORKQUEUE_ONLINE] = {
|
|
.name = "workqueue:online",
|
|
.startup.single = workqueue_online_cpu,
|
|
.teardown.single = workqueue_offline_cpu,
|
|
},
|
|
[CPUHP_AP_RCUTREE_ONLINE] = {
|
|
.name = "RCU/tree:online",
|
|
.startup.single = rcutree_online_cpu,
|
|
.teardown.single = rcutree_offline_cpu,
|
|
},
|
|
#endif
|
|
/*
|
|
* The dynamically registered state space is here
|
|
*/
|
|
|
|
#ifdef CONFIG_SMP
|
|
/* Last state is scheduler control setting the cpu active */
|
|
[CPUHP_AP_ACTIVE] = {
|
|
.name = "sched:active",
|
|
.startup.single = sched_cpu_activate,
|
|
.teardown.single = sched_cpu_deactivate,
|
|
},
|
|
#endif
|
|
|
|
/* CPU is fully up and running. */
|
|
[CPUHP_ONLINE] = {
|
|
.name = "online",
|
|
.startup.single = NULL,
|
|
.teardown.single = 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;
|
|
}
|
|
|
|
/*
|
|
* 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, end;
|
|
struct cpuhp_step *step;
|
|
|
|
switch (state) {
|
|
case CPUHP_AP_ONLINE_DYN:
|
|
step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN;
|
|
end = CPUHP_AP_ONLINE_DYN_END;
|
|
break;
|
|
case CPUHP_BP_PREPARE_DYN:
|
|
step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN;
|
|
end = CPUHP_BP_PREPARE_DYN_END;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
for (i = state; i <= end; i++, step++) {
|
|
if (!step->name)
|
|
return i;
|
|
}
|
|
WARN(1, "No more dynamic states available for CPU hotplug\n");
|
|
return -ENOSPC;
|
|
}
|
|
|
|
static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name,
|
|
int (*startup)(unsigned int cpu),
|
|
int (*teardown)(unsigned int cpu),
|
|
bool multi_instance)
|
|
{
|
|
/* (Un)Install the callbacks for further cpu hotplug operations */
|
|
struct cpuhp_step *sp;
|
|
int ret = 0;
|
|
|
|
if (state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN) {
|
|
ret = cpuhp_reserve_state(state);
|
|
if (ret < 0)
|
|
return ret;
|
|
state = ret;
|
|
}
|
|
sp = cpuhp_get_step(state);
|
|
if (name && sp->name)
|
|
return -EBUSY;
|
|
|
|
sp->startup.single = startup;
|
|
sp->teardown.single = teardown;
|
|
sp->name = name;
|
|
sp->multi_instance = multi_instance;
|
|
INIT_HLIST_HEAD(&sp->list);
|
|
return ret;
|
|
}
|
|
|
|
static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
|
|
{
|
|
return cpuhp_get_step(state)->teardown.single;
|
|
}
|
|
|
|
/*
|
|
* 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, bool bringup,
|
|
struct hlist_node *node)
|
|
{
|
|
struct cpuhp_step *sp = cpuhp_get_step(state);
|
|
int ret;
|
|
|
|
if ((bringup && !sp->startup.single) ||
|
|
(!bringup && !sp->teardown.single))
|
|
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, bringup, node);
|
|
else
|
|
ret = cpuhp_invoke_callback(cpu, state, bringup, node);
|
|
#else
|
|
ret = cpuhp_invoke_callback(cpu, state, bringup, node);
|
|
#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,
|
|
struct hlist_node *node)
|
|
{
|
|
int cpu;
|
|
|
|
/* 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, false, node);
|
|
}
|
|
}
|
|
|
|
int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
|
|
bool invoke)
|
|
{
|
|
struct cpuhp_step *sp;
|
|
int cpu;
|
|
int ret;
|
|
|
|
sp = cpuhp_get_step(state);
|
|
if (sp->multi_instance == false)
|
|
return -EINVAL;
|
|
|
|
get_online_cpus();
|
|
mutex_lock(&cpuhp_state_mutex);
|
|
|
|
if (!invoke || !sp->startup.multi)
|
|
goto add_node;
|
|
|
|
/*
|
|
* 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, true, node);
|
|
if (ret) {
|
|
if (sp->teardown.multi)
|
|
cpuhp_rollback_install(cpu, state, node);
|
|
goto unlock;
|
|
}
|
|
}
|
|
add_node:
|
|
ret = 0;
|
|
hlist_add_head(node, &sp->list);
|
|
unlock:
|
|
mutex_unlock(&cpuhp_state_mutex);
|
|
put_online_cpus();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
|
|
|
|
/**
|
|
* __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
|
|
* @multi_instance: State is set up for multiple instances which get
|
|
* added afterwards.
|
|
*
|
|
* Returns:
|
|
* On success:
|
|
* Positive state number if @state is CPUHP_AP_ONLINE_DYN
|
|
* 0 for all other states
|
|
* On failure: proper (negative) 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),
|
|
bool multi_instance)
|
|
{
|
|
int cpu, ret = 0;
|
|
bool dynstate;
|
|
|
|
if (cpuhp_cb_check(state) || !name)
|
|
return -EINVAL;
|
|
|
|
get_online_cpus();
|
|
mutex_lock(&cpuhp_state_mutex);
|
|
|
|
ret = cpuhp_store_callbacks(state, name, startup, teardown,
|
|
multi_instance);
|
|
|
|
dynstate = state == CPUHP_AP_ONLINE_DYN;
|
|
if (ret > 0 && dynstate) {
|
|
state = ret;
|
|
ret = 0;
|
|
}
|
|
|
|
if (ret || !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, true, NULL);
|
|
if (ret) {
|
|
if (teardown)
|
|
cpuhp_rollback_install(cpu, state, NULL);
|
|
cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
|
|
goto out;
|
|
}
|
|
}
|
|
out:
|
|
mutex_unlock(&cpuhp_state_mutex);
|
|
put_online_cpus();
|
|
/*
|
|
* If the requested state is CPUHP_AP_ONLINE_DYN, return the
|
|
* dynamically allocated state in case of success.
|
|
*/
|
|
if (!ret && dynstate)
|
|
return state;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(__cpuhp_setup_state);
|
|
|
|
int __cpuhp_state_remove_instance(enum cpuhp_state state,
|
|
struct hlist_node *node, bool invoke)
|
|
{
|
|
struct cpuhp_step *sp = cpuhp_get_step(state);
|
|
int cpu;
|
|
|
|
BUG_ON(cpuhp_cb_check(state));
|
|
|
|
if (!sp->multi_instance)
|
|
return -EINVAL;
|
|
|
|
get_online_cpus();
|
|
mutex_lock(&cpuhp_state_mutex);
|
|
|
|
if (!invoke || !cpuhp_get_teardown_cb(state))
|
|
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, false, node);
|
|
}
|
|
|
|
remove:
|
|
hlist_del(node);
|
|
mutex_unlock(&cpuhp_state_mutex);
|
|
put_online_cpus();
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance);
|
|
|
|
/**
|
|
* __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)
|
|
{
|
|
struct cpuhp_step *sp = cpuhp_get_step(state);
|
|
int cpu;
|
|
|
|
BUG_ON(cpuhp_cb_check(state));
|
|
|
|
get_online_cpus();
|
|
|
|
mutex_lock(&cpuhp_state_mutex);
|
|
if (sp->multi_instance) {
|
|
WARN(!hlist_empty(&sp->list),
|
|
"Error: Removing state %d which has instances left.\n",
|
|
state);
|
|
goto remove;
|
|
}
|
|
|
|
if (!invoke || !cpuhp_get_teardown_cb(state))
|
|
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, false, NULL);
|
|
}
|
|
remove:
|
|
cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
|
|
mutex_unlock(&cpuhp_state_mutex);
|
|
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)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
|
|
|
|
return sprintf(buf, "%d\n", st->state);
|
|
}
|
|
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)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
|
|
|
|
return sprintf(buf, "%d\n", st->target);
|
|
}
|
|
static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target);
|
|
|
|
static struct attribute *cpuhp_cpu_attrs[] = {
|
|
&dev_attr_state.attr,
|
|
&dev_attr_target.attr,
|
|
NULL
|
|
};
|
|
|
|
static struct attribute_group cpuhp_cpu_attr_group = {
|
|
.attrs = cpuhp_cpu_attrs,
|
|
.name = "hotplug",
|
|
NULL
|
|
};
|
|
|
|
static ssize_t show_cpuhp_states(struct device *dev,
|
|
struct device_attribute *attr, char *buf)
|
|
{
|
|
ssize_t cur, res = 0;
|
|
int i;
|
|
|
|
mutex_lock(&cpuhp_state_mutex);
|
|
for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) {
|
|
struct cpuhp_step *sp = cpuhp_get_step(i);
|
|
|
|
if (sp->name) {
|
|
cur = sprintf(buf, "%3d: %s\n", i, sp->name);
|
|
buf += cur;
|
|
res += cur;
|
|
}
|
|
}
|
|
mutex_unlock(&cpuhp_state_mutex);
|
|
return res;
|
|
}
|
|
static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL);
|
|
|
|
static struct attribute *cpuhp_cpu_root_attrs[] = {
|
|
&dev_attr_states.attr,
|
|
NULL
|
|
};
|
|
|
|
static struct attribute_group cpuhp_cpu_root_attr_group = {
|
|
.attrs = cpuhp_cpu_root_attrs,
|
|
.name = "hotplug",
|
|
NULL
|
|
};
|
|
|
|
static int __init cpuhp_sysfs_init(void)
|
|
{
|
|
int cpu, ret;
|
|
|
|
ret = sysfs_create_group(&cpu_subsys.dev_root->kobj,
|
|
&cpuhp_cpu_root_attr_group);
|
|
if (ret)
|
|
return ret;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
struct device *dev = get_cpu_device(cpu);
|
|
|
|
if (!dev)
|
|
continue;
|
|
ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
device_initcall(cpuhp_sysfs_init);
|
|
#endif
|
|
|
|
/*
|
|
* 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() 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);
|
|
|
|
const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
|
|
EXPORT_SYMBOL(cpu_all_bits);
|
|
|
|
#ifdef CONFIG_INIT_ALL_POSSIBLE
|
|
struct cpumask __cpu_possible_mask __read_mostly
|
|
= {CPU_BITS_ALL};
|
|
#else
|
|
struct cpumask __cpu_possible_mask __read_mostly;
|
|
#endif
|
|
EXPORT_SYMBOL(__cpu_possible_mask);
|
|
|
|
struct cpumask __cpu_online_mask __read_mostly;
|
|
EXPORT_SYMBOL(__cpu_online_mask);
|
|
|
|
struct cpumask __cpu_present_mask __read_mostly;
|
|
EXPORT_SYMBOL(__cpu_present_mask);
|
|
|
|
struct cpumask __cpu_active_mask __read_mostly;
|
|
EXPORT_SYMBOL(__cpu_active_mask);
|
|
|
|
void init_cpu_present(const struct cpumask *src)
|
|
{
|
|
cpumask_copy(&__cpu_present_mask, src);
|
|
}
|
|
|
|
void init_cpu_possible(const struct cpumask *src)
|
|
{
|
|
cpumask_copy(&__cpu_possible_mask, src);
|
|
}
|
|
|
|
void init_cpu_online(const struct cpumask *src)
|
|
{
|
|
cpumask_copy(&__cpu_online_mask, src);
|
|
}
|
|
|
|
/*
|
|
* Activate the first processor.
|
|
*/
|
|
void __init boot_cpu_init(void)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
|
|
/* Mark the boot cpu "present", "online" etc for SMP and UP case */
|
|
set_cpu_online(cpu, true);
|
|
set_cpu_active(cpu, true);
|
|
set_cpu_present(cpu, true);
|
|
set_cpu_possible(cpu, true);
|
|
|
|
#ifdef CONFIG_SMP
|
|
__boot_cpu_id = cpu;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Must be called _AFTER_ setting up the per_cpu areas
|
|
*/
|
|
void __init boot_cpu_state_init(void)
|
|
{
|
|
per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;
|
|
}
|