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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
Pull timer updates from Ingo Molnar: "This cycle had the following changes: - Timer tracing improvements (Anna-Maria Gleixner) - Continued tasklet reduction work: remove the hrtimer_tasklet (Thomas Gleixner) - Fix CPU hotplug remove race in the tick-broadcast mask handling code (Thomas Gleixner) - Force upper bound for setting CLOCK_REALTIME, to fix ABI inconsistencies with handling values that are close to the maximum supported and the vagueness of when uptime related wraparound might occur. Make the consistent maximum the year 2232 across all relevant ABIs and APIs. (Thomas Gleixner) - various cleanups and smaller fixes" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tick: Fix typos in comments tick/broadcast: Fix warning about undefined tick_broadcast_oneshot_offline() timekeeping: Force upper bound for setting CLOCK_REALTIME timer/trace: Improve timer tracing timer/trace: Replace deprecated vsprintf pointer extension %pf by %ps timer: Move trace point to get proper index tick/sched: Update tick_sched struct documentation tick: Remove outgoing CPU from broadcast masks timekeeping: Consistently use unsigned int for seqcount snapshot softirq: Remove tasklet_hrtimer xfrm: Replace hrtimer tasklet with softirq hrtimer mac80211_hwsim: Replace hrtimer tasklet with softirq hrtimer
2345 lines
56 KiB
C
2345 lines
56 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/isolation.h>
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#include <linux/sched/task.h>
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#include <linux/sched/smt.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/nmi.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 <linux/percpu-rwsem.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_up: Signal completion to the issuer of the task for cpu-up
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* @done_down: Signal completion to the issuer of the task for cpu-down
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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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enum cpuhp_state fail;
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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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bool booted_once;
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struct hlist_node *node;
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struct hlist_node *last;
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enum cpuhp_state cb_state;
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int result;
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struct completion done_up;
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struct completion done_down;
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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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.fail = CPUHP_INVALID,
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};
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#if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
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static struct lockdep_map cpuhp_state_up_map =
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STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
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static struct lockdep_map cpuhp_state_down_map =
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STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map);
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static inline void cpuhp_lock_acquire(bool bringup)
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{
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lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
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}
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static inline void cpuhp_lock_release(bool bringup)
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{
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lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
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}
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#else
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static inline void cpuhp_lock_acquire(bool bringup) { }
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static inline void cpuhp_lock_release(bool bringup) { }
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#endif
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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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* @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 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_hp_states[];
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static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
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{
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return cpuhp_hp_states + 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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* @state: The state to do callbacks for
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* @bringup: True if the bringup callback should be invoked
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* @node: For multi-instance, do a single entry callback for install/remove
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* @lastp: For multi-instance rollback, remember how far we got
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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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struct hlist_node **lastp)
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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 (st->fail == state) {
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st->fail = CPUHP_INVALID;
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if (!(bringup ? step->startup.single : step->teardown.single))
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return 0;
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return -EAGAIN;
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}
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if (!step->multi_instance) {
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WARN_ON_ONCE(lastp && *lastp);
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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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WARN_ON_ONCE(lastp && *lastp);
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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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if (lastp && node == *lastp)
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break;
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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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if (!lastp)
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goto err;
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*lastp = node;
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return ret;
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}
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cnt++;
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}
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if (lastp)
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*lastp = NULL;
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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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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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/*
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* Rollback must not fail,
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*/
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WARN_ON_ONCE(ret);
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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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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 inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
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{
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struct completion *done = bringup ? &st->done_up : &st->done_down;
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wait_for_completion(done);
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}
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static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
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{
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struct completion *done = bringup ? &st->done_up : &st->done_down;
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complete(done);
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}
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/*
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* The former STARTING/DYING states, ran with IRQs disabled and must not fail.
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*/
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static bool cpuhp_is_atomic_state(enum cpuhp_state state)
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{
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return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;
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}
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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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/*
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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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DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock);
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void cpus_read_lock(void)
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{
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percpu_down_read(&cpu_hotplug_lock);
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}
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EXPORT_SYMBOL_GPL(cpus_read_lock);
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int cpus_read_trylock(void)
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{
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return percpu_down_read_trylock(&cpu_hotplug_lock);
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}
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EXPORT_SYMBOL_GPL(cpus_read_trylock);
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void cpus_read_unlock(void)
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{
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percpu_up_read(&cpu_hotplug_lock);
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}
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EXPORT_SYMBOL_GPL(cpus_read_unlock);
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void cpus_write_lock(void)
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{
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percpu_down_write(&cpu_hotplug_lock);
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}
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void cpus_write_unlock(void)
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{
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percpu_up_write(&cpu_hotplug_lock);
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}
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void lockdep_assert_cpus_held(void)
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{
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/*
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* We can't have hotplug operations before userspace starts running,
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* and some init codepaths will knowingly not take the hotplug lock.
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* This is all valid, so mute lockdep until it makes sense to report
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* unheld locks.
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*/
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if (system_state < SYSTEM_RUNNING)
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return;
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percpu_rwsem_assert_held(&cpu_hotplug_lock);
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}
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static void lockdep_acquire_cpus_lock(void)
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{
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rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_);
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}
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static void lockdep_release_cpus_lock(void)
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{
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rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, 1, _THIS_IP_);
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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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#else
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static void lockdep_acquire_cpus_lock(void)
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{
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}
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static void lockdep_release_cpus_lock(void)
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{
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}
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#endif /* CONFIG_HOTPLUG_CPU */
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/*
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* Architectures that need SMT-specific errata handling during SMT hotplug
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* should override this.
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*/
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void __weak arch_smt_update(void) { }
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#ifdef CONFIG_HOTPLUG_SMT
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enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
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void __init cpu_smt_disable(bool force)
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{
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if (cpu_smt_control == CPU_SMT_FORCE_DISABLED ||
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cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
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return;
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if (force) {
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pr_info("SMT: Force disabled\n");
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cpu_smt_control = CPU_SMT_FORCE_DISABLED;
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} else {
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pr_info("SMT: disabled\n");
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cpu_smt_control = CPU_SMT_DISABLED;
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}
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}
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/*
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* The decision whether SMT is supported can only be done after the full
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* CPU identification. Called from architecture code.
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*/
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void __init cpu_smt_check_topology(void)
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{
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if (!topology_smt_supported())
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cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
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}
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static int __init smt_cmdline_disable(char *str)
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{
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cpu_smt_disable(str && !strcmp(str, "force"));
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return 0;
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}
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early_param("nosmt", smt_cmdline_disable);
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static inline bool cpu_smt_allowed(unsigned int cpu)
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{
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if (cpu_smt_control == CPU_SMT_ENABLED)
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return true;
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if (topology_is_primary_thread(cpu))
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return true;
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/*
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* On x86 it's required to boot all logical CPUs at least once so
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* that the init code can get a chance to set CR4.MCE on each
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* CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any
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* core will shutdown the machine.
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*/
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return !per_cpu(cpuhp_state, cpu).booted_once;
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}
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#else
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static inline bool cpu_smt_allowed(unsigned int cpu) { return true; }
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#endif
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static inline enum cpuhp_state
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cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target)
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{
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enum cpuhp_state prev_state = st->state;
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st->rollback = false;
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st->last = NULL;
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st->target = target;
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st->single = false;
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st->bringup = st->state < target;
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return prev_state;
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}
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static inline void
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cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state)
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{
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st->rollback = true;
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/*
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* If we have st->last we need to undo partial multi_instance of this
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* state first. Otherwise start undo at the previous state.
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*/
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if (!st->last) {
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if (st->bringup)
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st->state--;
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else
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st->state++;
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}
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st->target = prev_state;
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st->bringup = !st->bringup;
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}
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|
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/* Regular hotplug invocation of the AP hotplug thread */
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static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st)
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{
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if (!st->single && st->state == st->target)
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return;
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st->result = 0;
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/*
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* Make sure the above stores are visible before should_run becomes
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* true. Paired with the mb() above in cpuhp_thread_fun()
|
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*/
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smp_mb();
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st->should_run = true;
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wake_up_process(st->thread);
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wait_for_ap_thread(st, st->bringup);
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}
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static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target)
|
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{
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enum cpuhp_state prev_state;
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int ret;
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prev_state = cpuhp_set_state(st, target);
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__cpuhp_kick_ap(st);
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if ((ret = st->result)) {
|
|
cpuhp_reset_state(st, prev_state);
|
|
__cpuhp_kick_ap(st);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int bringup_wait_for_ap(unsigned int cpu)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
|
|
/* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
|
|
wait_for_ap_thread(st, true);
|
|
if (WARN_ON_ONCE((!cpu_online(cpu))))
|
|
return -ECANCELED;
|
|
|
|
/* Unpark the stopper thread and the hotplug thread of the target cpu */
|
|
stop_machine_unpark(cpu);
|
|
kthread_unpark(st->thread);
|
|
|
|
/*
|
|
* SMT soft disabling on X86 requires to bring the CPU out of the
|
|
* BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The
|
|
* CPU marked itself as booted_once in cpu_notify_starting() so the
|
|
* cpu_smt_allowed() check will now return false if this is not the
|
|
* primary sibling.
|
|
*/
|
|
if (!cpu_smt_allowed(cpu))
|
|
return -ECANCELED;
|
|
|
|
if (st->target <= CPUHP_AP_ONLINE_IDLE)
|
|
return 0;
|
|
|
|
return cpuhp_kick_ap(st, st->target);
|
|
}
|
|
|
|
static int bringup_cpu(unsigned int cpu)
|
|
{
|
|
struct task_struct *idle = idle_thread_get(cpu);
|
|
int ret;
|
|
|
|
/*
|
|
* Some architectures have to walk the irq descriptors to
|
|
* setup the vector space for the cpu which comes online.
|
|
* Prevent irq alloc/free across the bringup.
|
|
*/
|
|
irq_lock_sparse();
|
|
|
|
/* Arch-specific enabling code. */
|
|
ret = __cpu_up(cpu, idle);
|
|
irq_unlock_sparse();
|
|
if (ret)
|
|
return ret;
|
|
return bringup_wait_for_ap(cpu);
|
|
}
|
|
|
|
/*
|
|
* Hotplug state machine related functions
|
|
*/
|
|
|
|
static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
|
|
{
|
|
for (st->state--; st->state > st->target; st->state--)
|
|
cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
|
|
}
|
|
|
|
static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st)
|
|
{
|
|
if (IS_ENABLED(CONFIG_HOTPLUG_CPU))
|
|
return true;
|
|
/*
|
|
* When CPU hotplug is disabled, then taking the CPU down is not
|
|
* possible because takedown_cpu() and the architecture and
|
|
* subsystem specific mechanisms are not available. So the CPU
|
|
* which would be completely unplugged again needs to stay around
|
|
* in the current state.
|
|
*/
|
|
return st->state <= CPUHP_BRINGUP_CPU;
|
|
}
|
|
|
|
static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
|
|
enum cpuhp_state target)
|
|
{
|
|
enum cpuhp_state prev_state = st->state;
|
|
int ret = 0;
|
|
|
|
while (st->state < target) {
|
|
st->state++;
|
|
ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
|
|
if (ret) {
|
|
if (can_rollback_cpu(st)) {
|
|
st->target = prev_state;
|
|
undo_cpu_up(cpu, st);
|
|
}
|
|
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_up);
|
|
init_completion(&st->done_down);
|
|
}
|
|
|
|
static int cpuhp_should_run(unsigned int cpu)
|
|
{
|
|
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
|
|
|
|
return st->should_run;
|
|
}
|
|
|
|
/*
|
|
* Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
|
|
* callbacks when a state gets [un]installed at runtime.
|
|
*
|
|
* Each invocation of this function by the smpboot thread does a single AP
|
|
* state callback.
|
|
*
|
|
* It has 3 modes of operation:
|
|
* - single: runs st->cb_state
|
|
* - up: runs ++st->state, while st->state < st->target
|
|
* - down: runs st->state--, while st->state > st->target
|
|
*
|
|
* When complete or on error, should_run is cleared and the completion is fired.
|
|
*/
|
|
static void cpuhp_thread_fun(unsigned int cpu)
|
|
{
|
|
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
|
|
bool bringup = st->bringup;
|
|
enum cpuhp_state state;
|
|
|
|
if (WARN_ON_ONCE(!st->should_run))
|
|
return;
|
|
|
|
/*
|
|
* ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
|
|
* that if we see ->should_run we also see the rest of the state.
|
|
*/
|
|
smp_mb();
|
|
|
|
/*
|
|
* The BP holds the hotplug lock, but we're now running on the AP,
|
|
* ensure that anybody asserting the lock is held, will actually find
|
|
* it so.
|
|
*/
|
|
lockdep_acquire_cpus_lock();
|
|
cpuhp_lock_acquire(bringup);
|
|
|
|
if (st->single) {
|
|
state = st->cb_state;
|
|
st->should_run = false;
|
|
} else {
|
|
if (bringup) {
|
|
st->state++;
|
|
state = st->state;
|
|
st->should_run = (st->state < st->target);
|
|
WARN_ON_ONCE(st->state > st->target);
|
|
} else {
|
|
state = st->state;
|
|
st->state--;
|
|
st->should_run = (st->state > st->target);
|
|
WARN_ON_ONCE(st->state < st->target);
|
|
}
|
|
}
|
|
|
|
WARN_ON_ONCE(!cpuhp_is_ap_state(state));
|
|
|
|
if (cpuhp_is_atomic_state(state)) {
|
|
local_irq_disable();
|
|
st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
|
|
local_irq_enable();
|
|
|
|
/*
|
|
* STARTING/DYING must not fail!
|
|
*/
|
|
WARN_ON_ONCE(st->result);
|
|
} else {
|
|
st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
|
|
}
|
|
|
|
if (st->result) {
|
|
/*
|
|
* If we fail on a rollback, we're up a creek without no
|
|
* paddle, no way forward, no way back. We loose, thanks for
|
|
* playing.
|
|
*/
|
|
WARN_ON_ONCE(st->rollback);
|
|
st->should_run = false;
|
|
}
|
|
|
|
cpuhp_lock_release(bringup);
|
|
lockdep_release_cpus_lock();
|
|
|
|
if (!st->should_run)
|
|
complete_ap_thread(st, bringup);
|
|
}
|
|
|
|
/* 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);
|
|
int ret;
|
|
|
|
if (!cpu_online(cpu))
|
|
return 0;
|
|
|
|
cpuhp_lock_acquire(false);
|
|
cpuhp_lock_release(false);
|
|
|
|
cpuhp_lock_acquire(true);
|
|
cpuhp_lock_release(true);
|
|
|
|
/*
|
|
* 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, NULL);
|
|
|
|
st->rollback = false;
|
|
st->last = NULL;
|
|
|
|
st->node = node;
|
|
st->bringup = bringup;
|
|
st->cb_state = state;
|
|
st->single = true;
|
|
|
|
__cpuhp_kick_ap(st);
|
|
|
|
/*
|
|
* If we failed and did a partial, do a rollback.
|
|
*/
|
|
if ((ret = st->result) && st->last) {
|
|
st->rollback = true;
|
|
st->bringup = !bringup;
|
|
|
|
__cpuhp_kick_ap(st);
|
|
}
|
|
|
|
/*
|
|
* Clean up the leftovers so the next hotplug operation wont use stale
|
|
* data.
|
|
*/
|
|
st->node = st->last = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static int cpuhp_kick_ap_work(unsigned int cpu)
|
|
{
|
|
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
|
|
enum cpuhp_state prev_state = st->state;
|
|
int ret;
|
|
|
|
cpuhp_lock_acquire(false);
|
|
cpuhp_lock_release(false);
|
|
|
|
cpuhp_lock_acquire(true);
|
|
cpuhp_lock_release(true);
|
|
|
|
trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work);
|
|
ret = cpuhp_kick_ap(st, st->target);
|
|
trace_cpuhp_exit(cpu, st->state, prev_state, ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
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();
|
|
}
|
|
|
|
/* 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();
|
|
int ret;
|
|
|
|
/* 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--) {
|
|
ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
|
|
/*
|
|
* DYING must not fail!
|
|
*/
|
|
WARN_ON_ONCE(ret);
|
|
}
|
|
|
|
/* Give up timekeeping duties */
|
|
tick_handover_do_timer();
|
|
/* Remove CPU from timer broadcasting */
|
|
tick_offline_cpu(cpu);
|
|
/* 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);
|
|
|
|
/*
|
|
* 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_cpuslocked(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 teardown callback for CPUHP_AP_SCHED_STARTING 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_ap_thread(st, false);
|
|
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);
|
|
rcutree_migrate_callbacks(cpu);
|
|
return 0;
|
|
}
|
|
|
|
static void cpuhp_complete_idle_dead(void *arg)
|
|
{
|
|
struct cpuhp_cpu_state *st = arg;
|
|
|
|
complete_ap_thread(st, false);
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
|
|
{
|
|
for (st->state++; st->state < st->target; st->state++)
|
|
cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
|
|
}
|
|
|
|
static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
|
|
enum cpuhp_state target)
|
|
{
|
|
enum cpuhp_state prev_state = st->state;
|
|
int ret = 0;
|
|
|
|
for (; st->state > target; st->state--) {
|
|
ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL);
|
|
if (ret) {
|
|
st->target = prev_state;
|
|
if (st->state < prev_state)
|
|
undo_cpu_down(cpu, st);
|
|
break;
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* 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;
|
|
|
|
cpus_write_lock();
|
|
|
|
cpuhp_tasks_frozen = tasks_frozen;
|
|
|
|
prev_state = cpuhp_set_state(st, 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) {
|
|
st->target = max((int)target, 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;
|
|
|
|
st->target = target;
|
|
}
|
|
/*
|
|
* 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) {
|
|
cpuhp_reset_state(st, prev_state);
|
|
__cpuhp_kick_ap(st);
|
|
}
|
|
|
|
out:
|
|
cpus_write_unlock();
|
|
/*
|
|
* Do post unplug cleanup. This is still protected against
|
|
* concurrent CPU hotplug via cpu_add_remove_lock.
|
|
*/
|
|
lockup_detector_cleanup();
|
|
arch_smt_update();
|
|
return ret;
|
|
}
|
|
|
|
static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target)
|
|
{
|
|
if (cpu_hotplug_disabled)
|
|
return -EBUSY;
|
|
return _cpu_down(cpu, 0, target);
|
|
}
|
|
|
|
static int do_cpu_down(unsigned int cpu, enum cpuhp_state target)
|
|
{
|
|
int err;
|
|
|
|
cpu_maps_update_begin();
|
|
err = cpu_down_maps_locked(cpu, target);
|
|
cpu_maps_update_done();
|
|
return err;
|
|
}
|
|
|
|
int cpu_down(unsigned int cpu)
|
|
{
|
|
return do_cpu_down(cpu, CPUHP_OFFLINE);
|
|
}
|
|
EXPORT_SYMBOL(cpu_down);
|
|
|
|
#else
|
|
#define takedown_cpu NULL
|
|
#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);
|
|
int ret;
|
|
|
|
rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
|
|
st->booted_once = true;
|
|
while (st->state < target) {
|
|
st->state++;
|
|
ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL);
|
|
/*
|
|
* STARTING must not fail!
|
|
*/
|
|
WARN_ON_ONCE(ret);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called from the idle task. Wake up the controlling task which brings the
|
|
* stopper and the hotplug thread of the upcoming CPU up and then delegates
|
|
* the rest of the online bringup to the hotplug thread.
|
|
*/
|
|
void cpuhp_online_idle(enum cpuhp_state state)
|
|
{
|
|
struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
|
|
|
|
/* Happens for the boot cpu */
|
|
if (state != CPUHP_AP_ONLINE_IDLE)
|
|
return;
|
|
|
|
st->state = CPUHP_AP_ONLINE_IDLE;
|
|
complete_ap_thread(st, true);
|
|
}
|
|
|
|
/* 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;
|
|
|
|
cpus_write_lock();
|
|
|
|
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;
|
|
|
|
cpuhp_set_state(st, 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:
|
|
cpus_write_unlock();
|
|
arch_smt_update();
|
|
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;
|
|
}
|
|
if (!cpu_smt_allowed(cpu)) {
|
|
err = -EPERM;
|
|
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 (primary == -1) {
|
|
primary = cpumask_first(cpu_online_mask);
|
|
if (!housekeeping_cpu(primary, HK_FLAG_TIMER))
|
|
primary = housekeeping_any_cpu(HK_FLAG_TIMER);
|
|
} else {
|
|
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_hp_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_PREPARE] = {
|
|
.name = "timers:prepare",
|
|
.startup.single = timers_prepare_cpu,
|
|
.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,
|
|
},
|
|
/* 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,
|
|
},
|
|
[CPUHP_AP_SMPCFD_DYING] = {
|
|
.name = "smpcfd:dying",
|
|
.startup.single = NULL,
|
|
.teardown.single = smpcfd_dying_cpu,
|
|
},
|
|
/* Entry state on starting. Interrupts enabled from here on. Transient
|
|
* state for synchronsization */
|
|
[CPUHP_AP_ONLINE] = {
|
|
.name = "ap:online",
|
|
},
|
|
/*
|
|
* 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,
|
|
},
|
|
/* Handle smpboot threads park/unpark */
|
|
[CPUHP_AP_SMPBOOT_THREADS] = {
|
|
.name = "smpboot/threads:online",
|
|
.startup.single = smpboot_unpark_threads,
|
|
.teardown.single = smpboot_park_threads,
|
|
},
|
|
[CPUHP_AP_IRQ_AFFINITY_ONLINE] = {
|
|
.name = "irq/affinity:online",
|
|
.startup.single = irq_affinity_online_cpu,
|
|
.teardown.single = NULL,
|
|
},
|
|
[CPUHP_AP_PERF_ONLINE] = {
|
|
.name = "perf:online",
|
|
.startup.single = perf_event_init_cpu,
|
|
.teardown.single = perf_event_exit_cpu,
|
|
},
|
|
[CPUHP_AP_WATCHDOG_ONLINE] = {
|
|
.name = "lockup_detector:online",
|
|
.startup.single = lockup_detector_online_cpu,
|
|
.teardown.single = lockup_detector_offline_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_hp_states + CPUHP_AP_ONLINE_DYN;
|
|
end = CPUHP_AP_ONLINE_DYN_END;
|
|
break;
|
|
case CPUHP_BP_PREPARE_DYN:
|
|
step = cpuhp_hp_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 name is NULL, then the state gets removed.
|
|
*
|
|
* CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on
|
|
* the first allocation from these dynamic ranges, so the removal
|
|
* would trigger a new allocation and clear the wrong (already
|
|
* empty) state, leaving the callbacks of the to be cleared state
|
|
* dangling, which causes wreckage on the next hotplug operation.
|
|
*/
|
|
if (name && (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 there's nothing to do, we done.
|
|
* Relies on the union for multi_instance.
|
|
*/
|
|
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, NULL);
|
|
#else
|
|
ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
|
|
#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_cpuslocked(enum cpuhp_state state,
|
|
struct hlist_node *node,
|
|
bool invoke)
|
|
{
|
|
struct cpuhp_step *sp;
|
|
int cpu;
|
|
int ret;
|
|
|
|
lockdep_assert_cpus_held();
|
|
|
|
sp = cpuhp_get_step(state);
|
|
if (sp->multi_instance == false)
|
|
return -EINVAL;
|
|
|
|
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);
|
|
return ret;
|
|
}
|
|
|
|
int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
|
|
bool invoke)
|
|
{
|
|
int ret;
|
|
|
|
cpus_read_lock();
|
|
ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke);
|
|
cpus_read_unlock();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
|
|
|
|
/**
|
|
* __cpuhp_setup_state_cpuslocked - 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.
|
|
*
|
|
* The caller needs to hold cpus read locked while calling this function.
|
|
* 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_cpuslocked(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;
|
|
|
|
lockdep_assert_cpus_held();
|
|
|
|
if (cpuhp_cb_check(state) || !name)
|
|
return -EINVAL;
|
|
|
|
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);
|
|
/*
|
|
* 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_cpuslocked);
|
|
|
|
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 ret;
|
|
|
|
cpus_read_lock();
|
|
ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup,
|
|
teardown, multi_instance);
|
|
cpus_read_unlock();
|
|
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;
|
|
|
|
cpus_read_lock();
|
|
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);
|
|
cpus_read_unlock();
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance);
|
|
|
|
/**
|
|
* __cpuhp_remove_state_cpuslocked - 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 caller needs to hold cpus read locked while calling this function.
|
|
* The teardown callback is currently not allowed to fail. Think
|
|
* about module removal!
|
|
*/
|
|
void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke)
|
|
{
|
|
struct cpuhp_step *sp = cpuhp_get_step(state);
|
|
int cpu;
|
|
|
|
BUG_ON(cpuhp_cb_check(state));
|
|
|
|
lockdep_assert_cpus_held();
|
|
|
|
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);
|
|
}
|
|
EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked);
|
|
|
|
void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
|
|
{
|
|
cpus_read_lock();
|
|
__cpuhp_remove_state_cpuslocked(state, invoke);
|
|
cpus_read_unlock();
|
|
}
|
|
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)
|
|
goto out;
|
|
|
|
if (st->state < target)
|
|
ret = do_cpu_up(dev->id, target);
|
|
else
|
|
ret = do_cpu_down(dev->id, target);
|
|
out:
|
|
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 ssize_t write_cpuhp_fail(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 fail, ret;
|
|
|
|
ret = kstrtoint(buf, 10, &fail);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/*
|
|
* Cannot fail STARTING/DYING callbacks.
|
|
*/
|
|
if (cpuhp_is_atomic_state(fail))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Cannot fail anything that doesn't have callbacks.
|
|
*/
|
|
mutex_lock(&cpuhp_state_mutex);
|
|
sp = cpuhp_get_step(fail);
|
|
if (!sp->startup.single && !sp->teardown.single)
|
|
ret = -EINVAL;
|
|
mutex_unlock(&cpuhp_state_mutex);
|
|
if (ret)
|
|
return ret;
|
|
|
|
st->fail = fail;
|
|
|
|
return count;
|
|
}
|
|
|
|
static ssize_t show_cpuhp_fail(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->fail);
|
|
}
|
|
|
|
static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail);
|
|
|
|
static struct attribute *cpuhp_cpu_attrs[] = {
|
|
&dev_attr_state.attr,
|
|
&dev_attr_target.attr,
|
|
&dev_attr_fail.attr,
|
|
NULL
|
|
};
|
|
|
|
static const 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 const struct attribute_group cpuhp_cpu_root_attr_group = {
|
|
.attrs = cpuhp_cpu_root_attrs,
|
|
.name = "hotplug",
|
|
NULL
|
|
};
|
|
|
|
#ifdef CONFIG_HOTPLUG_SMT
|
|
|
|
static void cpuhp_offline_cpu_device(unsigned int cpu)
|
|
{
|
|
struct device *dev = get_cpu_device(cpu);
|
|
|
|
dev->offline = true;
|
|
/* Tell user space about the state change */
|
|
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
|
|
}
|
|
|
|
static void cpuhp_online_cpu_device(unsigned int cpu)
|
|
{
|
|
struct device *dev = get_cpu_device(cpu);
|
|
|
|
dev->offline = false;
|
|
/* Tell user space about the state change */
|
|
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
|
|
}
|
|
|
|
static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
|
|
{
|
|
int cpu, ret = 0;
|
|
|
|
cpu_maps_update_begin();
|
|
for_each_online_cpu(cpu) {
|
|
if (topology_is_primary_thread(cpu))
|
|
continue;
|
|
ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
|
|
if (ret)
|
|
break;
|
|
/*
|
|
* As this needs to hold the cpu maps lock it's impossible
|
|
* to call device_offline() because that ends up calling
|
|
* cpu_down() which takes cpu maps lock. cpu maps lock
|
|
* needs to be held as this might race against in kernel
|
|
* abusers of the hotplug machinery (thermal management).
|
|
*
|
|
* So nothing would update device:offline state. That would
|
|
* leave the sysfs entry stale and prevent onlining after
|
|
* smt control has been changed to 'off' again. This is
|
|
* called under the sysfs hotplug lock, so it is properly
|
|
* serialized against the regular offline usage.
|
|
*/
|
|
cpuhp_offline_cpu_device(cpu);
|
|
}
|
|
if (!ret)
|
|
cpu_smt_control = ctrlval;
|
|
cpu_maps_update_done();
|
|
return ret;
|
|
}
|
|
|
|
static int cpuhp_smt_enable(void)
|
|
{
|
|
int cpu, ret = 0;
|
|
|
|
cpu_maps_update_begin();
|
|
cpu_smt_control = CPU_SMT_ENABLED;
|
|
for_each_present_cpu(cpu) {
|
|
/* Skip online CPUs and CPUs on offline nodes */
|
|
if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
|
|
continue;
|
|
ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
|
|
if (ret)
|
|
break;
|
|
/* See comment in cpuhp_smt_disable() */
|
|
cpuhp_online_cpu_device(cpu);
|
|
}
|
|
cpu_maps_update_done();
|
|
return ret;
|
|
}
|
|
|
|
|
|
static ssize_t
|
|
__store_smt_control(struct device *dev, struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
int ctrlval, ret;
|
|
|
|
if (sysfs_streq(buf, "on"))
|
|
ctrlval = CPU_SMT_ENABLED;
|
|
else if (sysfs_streq(buf, "off"))
|
|
ctrlval = CPU_SMT_DISABLED;
|
|
else if (sysfs_streq(buf, "forceoff"))
|
|
ctrlval = CPU_SMT_FORCE_DISABLED;
|
|
else
|
|
return -EINVAL;
|
|
|
|
if (cpu_smt_control == CPU_SMT_FORCE_DISABLED)
|
|
return -EPERM;
|
|
|
|
if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
|
|
return -ENODEV;
|
|
|
|
ret = lock_device_hotplug_sysfs();
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (ctrlval != cpu_smt_control) {
|
|
switch (ctrlval) {
|
|
case CPU_SMT_ENABLED:
|
|
ret = cpuhp_smt_enable();
|
|
break;
|
|
case CPU_SMT_DISABLED:
|
|
case CPU_SMT_FORCE_DISABLED:
|
|
ret = cpuhp_smt_disable(ctrlval);
|
|
break;
|
|
}
|
|
}
|
|
|
|
unlock_device_hotplug();
|
|
return ret ? ret : count;
|
|
}
|
|
|
|
#else /* !CONFIG_HOTPLUG_SMT */
|
|
static ssize_t
|
|
__store_smt_control(struct device *dev, struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
return -ENODEV;
|
|
}
|
|
#endif /* CONFIG_HOTPLUG_SMT */
|
|
|
|
static const char *smt_states[] = {
|
|
[CPU_SMT_ENABLED] = "on",
|
|
[CPU_SMT_DISABLED] = "off",
|
|
[CPU_SMT_FORCE_DISABLED] = "forceoff",
|
|
[CPU_SMT_NOT_SUPPORTED] = "notsupported",
|
|
[CPU_SMT_NOT_IMPLEMENTED] = "notimplemented",
|
|
};
|
|
|
|
static ssize_t
|
|
show_smt_control(struct device *dev, struct device_attribute *attr, char *buf)
|
|
{
|
|
const char *state = smt_states[cpu_smt_control];
|
|
|
|
return snprintf(buf, PAGE_SIZE - 2, "%s\n", state);
|
|
}
|
|
|
|
static ssize_t
|
|
store_smt_control(struct device *dev, struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
return __store_smt_control(dev, attr, buf, count);
|
|
}
|
|
static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control);
|
|
|
|
static ssize_t
|
|
show_smt_active(struct device *dev, struct device_attribute *attr, char *buf)
|
|
{
|
|
return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active());
|
|
}
|
|
static DEVICE_ATTR(active, 0444, show_smt_active, NULL);
|
|
|
|
static struct attribute *cpuhp_smt_attrs[] = {
|
|
&dev_attr_control.attr,
|
|
&dev_attr_active.attr,
|
|
NULL
|
|
};
|
|
|
|
static const struct attribute_group cpuhp_smt_attr_group = {
|
|
.attrs = cpuhp_smt_attrs,
|
|
.name = "smt",
|
|
NULL
|
|
};
|
|
|
|
static int __init cpu_smt_sysfs_init(void)
|
|
{
|
|
return sysfs_create_group(&cpu_subsys.dev_root->kobj,
|
|
&cpuhp_smt_attr_group);
|
|
}
|
|
|
|
static int __init cpuhp_sysfs_init(void)
|
|
{
|
|
int cpu, ret;
|
|
|
|
ret = cpu_smt_sysfs_init();
|
|
if (ret)
|
|
return 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 /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */
|
|
|
|
/*
|
|
* 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_hotplug_init(void)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
this_cpu_write(cpuhp_state.booted_once, true);
|
|
#endif
|
|
this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
|
|
}
|
|
|
|
enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO;
|
|
|
|
static int __init mitigations_parse_cmdline(char *arg)
|
|
{
|
|
if (!strcmp(arg, "off"))
|
|
cpu_mitigations = CPU_MITIGATIONS_OFF;
|
|
else if (!strcmp(arg, "auto"))
|
|
cpu_mitigations = CPU_MITIGATIONS_AUTO;
|
|
else if (!strcmp(arg, "auto,nosmt"))
|
|
cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
|
|
|
|
return 0;
|
|
}
|
|
early_param("mitigations", mitigations_parse_cmdline);
|