Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* CPU control. |
| 2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell |
| 3 | * |
| 4 | * This code is licenced under the GPL. |
| 5 | */ |
| 6 | #include <linux/proc_fs.h> |
| 7 | #include <linux/smp.h> |
| 8 | #include <linux/init.h> |
| 9 | #include <linux/notifier.h> |
| 10 | #include <linux/sched.h> |
| 11 | #include <linux/unistd.h> |
| 12 | #include <linux/cpu.h> |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 13 | #include <linux/oom.h> |
| 14 | #include <linux/rcupdate.h> |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 15 | #include <linux/export.h> |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 16 | #include <linux/bug.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/kthread.h> |
| 18 | #include <linux/stop_machine.h> |
Ingo Molnar | 81615b62 | 2006-06-26 00:24:32 -0700 | [diff] [blame] | 19 | #include <linux/mutex.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 20 | #include <linux/gfp.h> |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 21 | #include <linux/suspend.h> |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 22 | #include <linux/lockdep.h> |
Preeti U Murthy | 345527b | 2015-03-30 14:59:19 +0530 | [diff] [blame] | 23 | #include <linux/tick.h> |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 24 | #include <linux/irq.h> |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 25 | #include <linux/smpboot.h> |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 26 | |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 27 | #include <trace/events/power.h> |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 28 | #define CREATE_TRACE_POINTS |
| 29 | #include <trace/events/cpuhp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 31 | #include "smpboot.h" |
| 32 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 33 | /** |
| 34 | * cpuhp_cpu_state - Per cpu hotplug state storage |
| 35 | * @state: The current cpu state |
| 36 | * @target: The target state |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 37 | * @thread: Pointer to the hotplug thread |
| 38 | * @should_run: Thread should execute |
| 39 | * @cb_stat: The state for a single callback (install/uninstall) |
| 40 | * @cb: Single callback function (install/uninstall) |
| 41 | * @result: Result of the operation |
| 42 | * @done: Signal completion to the issuer of the task |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 43 | */ |
| 44 | struct cpuhp_cpu_state { |
| 45 | enum cpuhp_state state; |
| 46 | enum cpuhp_state target; |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 47 | #ifdef CONFIG_SMP |
| 48 | struct task_struct *thread; |
| 49 | bool should_run; |
| 50 | enum cpuhp_state cb_state; |
| 51 | int (*cb)(unsigned int cpu); |
| 52 | int result; |
| 53 | struct completion done; |
| 54 | #endif |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 55 | }; |
| 56 | |
| 57 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); |
| 58 | |
| 59 | /** |
| 60 | * cpuhp_step - Hotplug state machine step |
| 61 | * @name: Name of the step |
| 62 | * @startup: Startup function of the step |
| 63 | * @teardown: Teardown function of the step |
| 64 | * @skip_onerr: Do not invoke the functions on error rollback |
| 65 | * Will go away once the notifiers are gone |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 66 | * @cant_stop: Bringup/teardown can't be stopped at this step |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 67 | */ |
| 68 | struct cpuhp_step { |
| 69 | const char *name; |
| 70 | int (*startup)(unsigned int cpu); |
| 71 | int (*teardown)(unsigned int cpu); |
| 72 | bool skip_onerr; |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 73 | bool cant_stop; |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 74 | }; |
| 75 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 76 | static DEFINE_MUTEX(cpuhp_state_mutex); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 77 | static struct cpuhp_step cpuhp_bp_states[]; |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 78 | static struct cpuhp_step cpuhp_ap_states[]; |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 79 | |
| 80 | /** |
| 81 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state |
| 82 | * @cpu: The cpu for which the callback should be invoked |
| 83 | * @step: The step in the state machine |
| 84 | * @cb: The callback function to invoke |
| 85 | * |
| 86 | * Called from cpu hotplug and from the state register machinery |
| 87 | */ |
| 88 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state step, |
| 89 | int (*cb)(unsigned int)) |
| 90 | { |
| 91 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 92 | int ret = 0; |
| 93 | |
| 94 | if (cb) { |
| 95 | trace_cpuhp_enter(cpu, st->target, step, cb); |
| 96 | ret = cb(cpu); |
| 97 | trace_cpuhp_exit(cpu, st->state, step, ret); |
| 98 | } |
| 99 | return ret; |
| 100 | } |
| 101 | |
Rusty Russell | 98a79d6 | 2008-12-13 21:19:41 +1030 | [diff] [blame] | 102 | #ifdef CONFIG_SMP |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 103 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
Linus Torvalds | aa95387 | 2006-07-23 12:12:16 -0700 | [diff] [blame] | 104 | static DEFINE_MUTEX(cpu_add_remove_lock); |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 105 | bool cpuhp_tasks_frozen; |
| 106 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 108 | /* |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 109 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
| 110 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. |
| 111 | * The APIs cpu_notifier_register_begin/done() must be used to protect CPU |
| 112 | * hotplug callback (un)registration performed using __register_cpu_notifier() |
| 113 | * or __unregister_cpu_notifier(). |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 114 | */ |
| 115 | void cpu_maps_update_begin(void) |
| 116 | { |
| 117 | mutex_lock(&cpu_add_remove_lock); |
| 118 | } |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 119 | EXPORT_SYMBOL(cpu_notifier_register_begin); |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 120 | |
| 121 | void cpu_maps_update_done(void) |
| 122 | { |
| 123 | mutex_unlock(&cpu_add_remove_lock); |
| 124 | } |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 125 | EXPORT_SYMBOL(cpu_notifier_register_done); |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 126 | |
Daniel J Blueman | 5c113fb | 2010-06-01 12:15:11 +0100 | [diff] [blame] | 127 | static RAW_NOTIFIER_HEAD(cpu_chain); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 129 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
| 130 | * Should always be manipulated under cpu_add_remove_lock |
| 131 | */ |
| 132 | static int cpu_hotplug_disabled; |
| 133 | |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 134 | #ifdef CONFIG_HOTPLUG_CPU |
| 135 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 136 | static struct { |
| 137 | struct task_struct *active_writer; |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 138 | /* wait queue to wake up the active_writer */ |
| 139 | wait_queue_head_t wq; |
| 140 | /* verifies that no writer will get active while readers are active */ |
| 141 | struct mutex lock; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 142 | /* |
| 143 | * Also blocks the new readers during |
| 144 | * an ongoing cpu hotplug operation. |
| 145 | */ |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 146 | atomic_t refcount; |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 147 | |
| 148 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 149 | struct lockdep_map dep_map; |
| 150 | #endif |
Linus Torvalds | 31950eb | 2009-06-22 21:18:12 -0700 | [diff] [blame] | 151 | } cpu_hotplug = { |
| 152 | .active_writer = NULL, |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 153 | .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq), |
Linus Torvalds | 31950eb | 2009-06-22 21:18:12 -0700 | [diff] [blame] | 154 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 155 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 156 | .dep_map = {.name = "cpu_hotplug.lock" }, |
| 157 | #endif |
Linus Torvalds | 31950eb | 2009-06-22 21:18:12 -0700 | [diff] [blame] | 158 | }; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 159 | |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 160 | /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */ |
| 161 | #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map) |
Paul E. McKenney | dd56af4 | 2014-08-25 20:25:06 -0700 | [diff] [blame] | 162 | #define cpuhp_lock_acquire_tryread() \ |
| 163 | lock_map_acquire_tryread(&cpu_hotplug.dep_map) |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 164 | #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) |
| 165 | #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) |
| 166 | |
Paul E. McKenney | 62db99f | 2014-10-22 14:51:49 -0700 | [diff] [blame] | 167 | |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 168 | void get_online_cpus(void) |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 169 | { |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 170 | might_sleep(); |
| 171 | if (cpu_hotplug.active_writer == current) |
Linus Torvalds | aa95387 | 2006-07-23 12:12:16 -0700 | [diff] [blame] | 172 | return; |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 173 | cpuhp_lock_acquire_read(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 174 | mutex_lock(&cpu_hotplug.lock); |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 175 | atomic_inc(&cpu_hotplug.refcount); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 176 | mutex_unlock(&cpu_hotplug.lock); |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 177 | } |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 178 | EXPORT_SYMBOL_GPL(get_online_cpus); |
Ashok Raj | 90d45d1 | 2005-11-08 21:34:24 -0800 | [diff] [blame] | 179 | |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 180 | void put_online_cpus(void) |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 181 | { |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 182 | int refcount; |
| 183 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 184 | if (cpu_hotplug.active_writer == current) |
Linus Torvalds | aa95387 | 2006-07-23 12:12:16 -0700 | [diff] [blame] | 185 | return; |
Srivatsa S. Bhat | 075663d | 2012-10-08 16:28:20 -0700 | [diff] [blame] | 186 | |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 187 | refcount = atomic_dec_return(&cpu_hotplug.refcount); |
| 188 | if (WARN_ON(refcount < 0)) /* try to fix things up */ |
| 189 | atomic_inc(&cpu_hotplug.refcount); |
Srivatsa S. Bhat | 075663d | 2012-10-08 16:28:20 -0700 | [diff] [blame] | 190 | |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 191 | if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq)) |
| 192 | wake_up(&cpu_hotplug.wq); |
| 193 | |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 194 | cpuhp_lock_release(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 195 | |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 196 | } |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 197 | EXPORT_SYMBOL_GPL(put_online_cpus); |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 198 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 199 | /* |
| 200 | * This ensures that the hotplug operation can begin only when the |
| 201 | * refcount goes to zero. |
| 202 | * |
| 203 | * Note that during a cpu-hotplug operation, the new readers, if any, |
| 204 | * will be blocked by the cpu_hotplug.lock |
| 205 | * |
Oleg Nesterov | d2ba7e2 | 2008-04-29 01:00:29 -0700 | [diff] [blame] | 206 | * Since cpu_hotplug_begin() is always called after invoking |
| 207 | * cpu_maps_update_begin(), we can be sure that only one writer is active. |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 208 | * |
| 209 | * Note that theoretically, there is a possibility of a livelock: |
| 210 | * - Refcount goes to zero, last reader wakes up the sleeping |
| 211 | * writer. |
| 212 | * - Last reader unlocks the cpu_hotplug.lock. |
| 213 | * - A new reader arrives at this moment, bumps up the refcount. |
| 214 | * - The writer acquires the cpu_hotplug.lock finds the refcount |
| 215 | * non zero and goes to sleep again. |
| 216 | * |
| 217 | * However, this is very difficult to achieve in practice since |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 218 | * get_online_cpus() not an api which is called all that often. |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 219 | * |
| 220 | */ |
Toshi Kani | b9d10be | 2013-08-12 09:45:53 -0600 | [diff] [blame] | 221 | void cpu_hotplug_begin(void) |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 222 | { |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 223 | DEFINE_WAIT(wait); |
Oleg Nesterov | d2ba7e2 | 2008-04-29 01:00:29 -0700 | [diff] [blame] | 224 | |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 225 | cpu_hotplug.active_writer = current; |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 226 | cpuhp_lock_acquire(); |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 227 | |
Oleg Nesterov | d2ba7e2 | 2008-04-29 01:00:29 -0700 | [diff] [blame] | 228 | for (;;) { |
| 229 | mutex_lock(&cpu_hotplug.lock); |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 230 | prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE); |
| 231 | if (likely(!atomic_read(&cpu_hotplug.refcount))) |
| 232 | break; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 233 | mutex_unlock(&cpu_hotplug.lock); |
| 234 | schedule(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 235 | } |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 236 | finish_wait(&cpu_hotplug.wq, &wait); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 237 | } |
| 238 | |
Toshi Kani | b9d10be | 2013-08-12 09:45:53 -0600 | [diff] [blame] | 239 | void cpu_hotplug_done(void) |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 240 | { |
| 241 | cpu_hotplug.active_writer = NULL; |
| 242 | mutex_unlock(&cpu_hotplug.lock); |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 243 | cpuhp_lock_release(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 244 | } |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 245 | |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 246 | /* |
| 247 | * Wait for currently running CPU hotplug operations to complete (if any) and |
| 248 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects |
| 249 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the |
| 250 | * hotplug path before performing hotplug operations. So acquiring that lock |
| 251 | * guarantees mutual exclusion from any currently running hotplug operations. |
| 252 | */ |
| 253 | void cpu_hotplug_disable(void) |
| 254 | { |
| 255 | cpu_maps_update_begin(); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 256 | cpu_hotplug_disabled++; |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 257 | cpu_maps_update_done(); |
| 258 | } |
Vitaly Kuznetsov | 32145c4 | 2015-08-05 00:52:47 -0700 | [diff] [blame] | 259 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 260 | |
| 261 | void cpu_hotplug_enable(void) |
| 262 | { |
| 263 | cpu_maps_update_begin(); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 264 | WARN_ON(--cpu_hotplug_disabled < 0); |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 265 | cpu_maps_update_done(); |
| 266 | } |
Vitaly Kuznetsov | 32145c4 | 2015-08-05 00:52:47 -0700 | [diff] [blame] | 267 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
Toshi Kani | b9d10be | 2013-08-12 09:45:53 -0600 | [diff] [blame] | 268 | #endif /* CONFIG_HOTPLUG_CPU */ |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 269 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | /* Need to know about CPUs going up/down? */ |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 271 | int register_cpu_notifier(struct notifier_block *nb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 272 | { |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 273 | int ret; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 274 | cpu_maps_update_begin(); |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 275 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 276 | cpu_maps_update_done(); |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 277 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 278 | } |
Chandra Seetharaman | 65edc68 | 2006-06-27 02:54:08 -0700 | [diff] [blame] | 279 | |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 280 | int __register_cpu_notifier(struct notifier_block *nb) |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 281 | { |
| 282 | return raw_notifier_chain_register(&cpu_chain, nb); |
| 283 | } |
| 284 | |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 285 | static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call, |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 286 | int *nr_calls) |
| 287 | { |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 288 | unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0; |
| 289 | void *hcpu = (void *)(long)cpu; |
| 290 | |
Akinobu Mita | e6bde73 | 2010-05-26 14:43:29 -0700 | [diff] [blame] | 291 | int ret; |
| 292 | |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 293 | ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call, |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 294 | nr_calls); |
Akinobu Mita | e6bde73 | 2010-05-26 14:43:29 -0700 | [diff] [blame] | 295 | |
| 296 | return notifier_to_errno(ret); |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 297 | } |
| 298 | |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 299 | static int cpu_notify(unsigned long val, unsigned int cpu) |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 300 | { |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 301 | return __cpu_notify(val, cpu, -1, NULL); |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 302 | } |
| 303 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 304 | /* Notifier wrappers for transitioning to state machine */ |
| 305 | static int notify_prepare(unsigned int cpu) |
| 306 | { |
| 307 | int nr_calls = 0; |
| 308 | int ret; |
| 309 | |
| 310 | ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls); |
| 311 | if (ret) { |
| 312 | nr_calls--; |
| 313 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", |
| 314 | __func__, cpu); |
| 315 | __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL); |
| 316 | } |
| 317 | return ret; |
| 318 | } |
| 319 | |
| 320 | static int notify_online(unsigned int cpu) |
| 321 | { |
| 322 | cpu_notify(CPU_ONLINE, cpu); |
| 323 | return 0; |
| 324 | } |
| 325 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 326 | static int notify_starting(unsigned int cpu) |
| 327 | { |
| 328 | cpu_notify(CPU_STARTING, cpu); |
| 329 | return 0; |
| 330 | } |
| 331 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 332 | static int bringup_cpu(unsigned int cpu) |
| 333 | { |
| 334 | struct task_struct *idle = idle_thread_get(cpu); |
| 335 | int ret; |
| 336 | |
| 337 | /* Arch-specific enabling code. */ |
| 338 | ret = __cpu_up(cpu, idle); |
| 339 | if (ret) { |
| 340 | cpu_notify(CPU_UP_CANCELED, cpu); |
| 341 | return ret; |
| 342 | } |
| 343 | BUG_ON(!cpu_online(cpu)); |
| 344 | return 0; |
| 345 | } |
| 346 | |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 347 | /* |
| 348 | * Hotplug state machine related functions |
| 349 | */ |
| 350 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st, |
| 351 | struct cpuhp_step *steps) |
| 352 | { |
| 353 | for (st->state++; st->state < st->target; st->state++) { |
| 354 | struct cpuhp_step *step = steps + st->state; |
| 355 | |
| 356 | if (!step->skip_onerr) |
| 357 | cpuhp_invoke_callback(cpu, st->state, step->startup); |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
| 362 | struct cpuhp_step *steps, enum cpuhp_state target) |
| 363 | { |
| 364 | enum cpuhp_state prev_state = st->state; |
| 365 | int ret = 0; |
| 366 | |
| 367 | for (; st->state > target; st->state--) { |
| 368 | struct cpuhp_step *step = steps + st->state; |
| 369 | |
| 370 | ret = cpuhp_invoke_callback(cpu, st->state, step->teardown); |
| 371 | if (ret) { |
| 372 | st->target = prev_state; |
| 373 | undo_cpu_down(cpu, st, steps); |
| 374 | break; |
| 375 | } |
| 376 | } |
| 377 | return ret; |
| 378 | } |
| 379 | |
| 380 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st, |
| 381 | struct cpuhp_step *steps) |
| 382 | { |
| 383 | for (st->state--; st->state > st->target; st->state--) { |
| 384 | struct cpuhp_step *step = steps + st->state; |
| 385 | |
| 386 | if (!step->skip_onerr) |
| 387 | cpuhp_invoke_callback(cpu, st->state, step->teardown); |
| 388 | } |
| 389 | } |
| 390 | |
| 391 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
| 392 | struct cpuhp_step *steps, enum cpuhp_state target) |
| 393 | { |
| 394 | enum cpuhp_state prev_state = st->state; |
| 395 | int ret = 0; |
| 396 | |
| 397 | while (st->state < target) { |
| 398 | struct cpuhp_step *step; |
| 399 | |
| 400 | st->state++; |
| 401 | step = steps + st->state; |
| 402 | ret = cpuhp_invoke_callback(cpu, st->state, step->startup); |
| 403 | if (ret) { |
| 404 | st->target = prev_state; |
| 405 | undo_cpu_up(cpu, st, steps); |
| 406 | break; |
| 407 | } |
| 408 | } |
| 409 | return ret; |
| 410 | } |
| 411 | |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 412 | /* |
| 413 | * The cpu hotplug threads manage the bringup and teardown of the cpus |
| 414 | */ |
| 415 | static void cpuhp_create(unsigned int cpu) |
| 416 | { |
| 417 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 418 | |
| 419 | init_completion(&st->done); |
| 420 | } |
| 421 | |
| 422 | static int cpuhp_should_run(unsigned int cpu) |
| 423 | { |
| 424 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 425 | |
| 426 | return st->should_run; |
| 427 | } |
| 428 | |
| 429 | /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */ |
| 430 | static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 431 | { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 432 | enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 433 | |
| 434 | return cpuhp_down_callbacks(cpu, st, cpuhp_ap_states, target); |
| 435 | } |
| 436 | |
| 437 | /* Execute the online startup callbacks. Used to be CPU_ONLINE */ |
| 438 | static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 439 | { |
| 440 | return cpuhp_up_callbacks(cpu, st, cpuhp_ap_states, st->target); |
| 441 | } |
| 442 | |
| 443 | /* |
| 444 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke |
| 445 | * callbacks when a state gets [un]installed at runtime. |
| 446 | */ |
| 447 | static void cpuhp_thread_fun(unsigned int cpu) |
| 448 | { |
| 449 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 450 | int ret = 0; |
| 451 | |
| 452 | /* |
| 453 | * Paired with the mb() in cpuhp_kick_ap_work and |
| 454 | * cpuhp_invoke_ap_callback, so the work set is consistent visible. |
| 455 | */ |
| 456 | smp_mb(); |
| 457 | if (!st->should_run) |
| 458 | return; |
| 459 | |
| 460 | st->should_run = false; |
| 461 | |
| 462 | /* Single callback invocation for [un]install ? */ |
| 463 | if (st->cb) { |
| 464 | if (st->cb_state < CPUHP_AP_ONLINE) { |
| 465 | local_irq_disable(); |
| 466 | ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb); |
| 467 | local_irq_enable(); |
| 468 | } else { |
| 469 | ret = cpuhp_invoke_callback(cpu, st->cb_state, st->cb); |
| 470 | } |
| 471 | } else { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 472 | /* Cannot happen .... */ |
| 473 | BUG_ON(st->state < CPUHP_KICK_AP_THREAD); |
| 474 | |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 475 | /* Regular hotplug work */ |
| 476 | if (st->state < st->target) |
| 477 | ret = cpuhp_ap_online(cpu, st); |
| 478 | else if (st->state > st->target) |
| 479 | ret = cpuhp_ap_offline(cpu, st); |
| 480 | } |
| 481 | st->result = ret; |
| 482 | complete(&st->done); |
| 483 | } |
| 484 | |
| 485 | /* Invoke a single callback on a remote cpu */ |
| 486 | static int cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, |
| 487 | int (*cb)(unsigned int)) |
| 488 | { |
| 489 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 490 | |
| 491 | if (!cpu_online(cpu)) |
| 492 | return 0; |
| 493 | |
| 494 | st->cb_state = state; |
| 495 | st->cb = cb; |
| 496 | /* |
| 497 | * Make sure the above stores are visible before should_run becomes |
| 498 | * true. Paired with the mb() above in cpuhp_thread_fun() |
| 499 | */ |
| 500 | smp_mb(); |
| 501 | st->should_run = true; |
| 502 | wake_up_process(st->thread); |
| 503 | wait_for_completion(&st->done); |
| 504 | return st->result; |
| 505 | } |
| 506 | |
| 507 | /* Regular hotplug invocation of the AP hotplug thread */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 508 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st) |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 509 | { |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 510 | st->result = 0; |
| 511 | st->cb = NULL; |
| 512 | /* |
| 513 | * Make sure the above stores are visible before should_run becomes |
| 514 | * true. Paired with the mb() above in cpuhp_thread_fun() |
| 515 | */ |
| 516 | smp_mb(); |
| 517 | st->should_run = true; |
| 518 | wake_up_process(st->thread); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 519 | } |
| 520 | |
| 521 | static int cpuhp_kick_ap_work(unsigned int cpu) |
| 522 | { |
| 523 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 524 | enum cpuhp_state state = st->state; |
| 525 | |
| 526 | trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); |
| 527 | __cpuhp_kick_ap_work(st); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 528 | wait_for_completion(&st->done); |
| 529 | trace_cpuhp_exit(cpu, st->state, state, st->result); |
| 530 | return st->result; |
| 531 | } |
| 532 | |
| 533 | static struct smp_hotplug_thread cpuhp_threads = { |
| 534 | .store = &cpuhp_state.thread, |
| 535 | .create = &cpuhp_create, |
| 536 | .thread_should_run = cpuhp_should_run, |
| 537 | .thread_fn = cpuhp_thread_fun, |
| 538 | .thread_comm = "cpuhp/%u", |
| 539 | .selfparking = true, |
| 540 | }; |
| 541 | |
| 542 | void __init cpuhp_threads_init(void) |
| 543 | { |
| 544 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); |
| 545 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); |
| 546 | } |
| 547 | |
Linus Torvalds | 00b9b0a | 2010-05-27 10:32:08 -0700 | [diff] [blame] | 548 | #ifdef CONFIG_HOTPLUG_CPU |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 549 | EXPORT_SYMBOL(register_cpu_notifier); |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 550 | EXPORT_SYMBOL(__register_cpu_notifier); |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 551 | void unregister_cpu_notifier(struct notifier_block *nb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | { |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 553 | cpu_maps_update_begin(); |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 554 | raw_notifier_chain_unregister(&cpu_chain, nb); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 555 | cpu_maps_update_done(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 556 | } |
| 557 | EXPORT_SYMBOL(unregister_cpu_notifier); |
| 558 | |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 559 | void __unregister_cpu_notifier(struct notifier_block *nb) |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 560 | { |
| 561 | raw_notifier_chain_unregister(&cpu_chain, nb); |
| 562 | } |
| 563 | EXPORT_SYMBOL(__unregister_cpu_notifier); |
| 564 | |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 565 | /** |
| 566 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU |
| 567 | * @cpu: a CPU id |
| 568 | * |
| 569 | * This function walks all processes, finds a valid mm struct for each one and |
| 570 | * then clears a corresponding bit in mm's cpumask. While this all sounds |
| 571 | * trivial, there are various non-obvious corner cases, which this function |
| 572 | * tries to solve in a safe manner. |
| 573 | * |
| 574 | * Also note that the function uses a somewhat relaxed locking scheme, so it may |
| 575 | * be called only for an already offlined CPU. |
| 576 | */ |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 577 | void clear_tasks_mm_cpumask(int cpu) |
| 578 | { |
| 579 | struct task_struct *p; |
| 580 | |
| 581 | /* |
| 582 | * This function is called after the cpu is taken down and marked |
| 583 | * offline, so its not like new tasks will ever get this cpu set in |
| 584 | * their mm mask. -- Peter Zijlstra |
| 585 | * Thus, we may use rcu_read_lock() here, instead of grabbing |
| 586 | * full-fledged tasklist_lock. |
| 587 | */ |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 588 | WARN_ON(cpu_online(cpu)); |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 589 | rcu_read_lock(); |
| 590 | for_each_process(p) { |
| 591 | struct task_struct *t; |
| 592 | |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 593 | /* |
| 594 | * Main thread might exit, but other threads may still have |
| 595 | * a valid mm. Find one. |
| 596 | */ |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 597 | t = find_lock_task_mm(p); |
| 598 | if (!t) |
| 599 | continue; |
| 600 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); |
| 601 | task_unlock(t); |
| 602 | } |
| 603 | rcu_read_unlock(); |
| 604 | } |
| 605 | |
Kirill Tkhai | b728ca0 | 2014-06-25 12:19:55 +0400 | [diff] [blame] | 606 | static inline void check_for_tasks(int dead_cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 607 | { |
Kirill Tkhai | b728ca0 | 2014-06-25 12:19:55 +0400 | [diff] [blame] | 608 | struct task_struct *g, *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 609 | |
Oleg Nesterov | a75a606 | 2015-09-10 15:07:50 +0200 | [diff] [blame] | 610 | read_lock(&tasklist_lock); |
| 611 | for_each_process_thread(g, p) { |
Kirill Tkhai | b728ca0 | 2014-06-25 12:19:55 +0400 | [diff] [blame] | 612 | if (!p->on_rq) |
| 613 | continue; |
| 614 | /* |
| 615 | * We do the check with unlocked task_rq(p)->lock. |
| 616 | * Order the reading to do not warn about a task, |
| 617 | * which was running on this cpu in the past, and |
| 618 | * it's just been woken on another cpu. |
| 619 | */ |
| 620 | rmb(); |
| 621 | if (task_cpu(p) != dead_cpu) |
| 622 | continue; |
| 623 | |
| 624 | pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n", |
| 625 | p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags); |
Oleg Nesterov | a75a606 | 2015-09-10 15:07:50 +0200 | [diff] [blame] | 626 | } |
| 627 | read_unlock(&tasklist_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 628 | } |
| 629 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 630 | static void cpu_notify_nofail(unsigned long val, unsigned int cpu) |
| 631 | { |
| 632 | BUG_ON(cpu_notify(val, cpu)); |
| 633 | } |
| 634 | |
| 635 | static int notify_down_prepare(unsigned int cpu) |
| 636 | { |
| 637 | int err, nr_calls = 0; |
| 638 | |
| 639 | err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls); |
| 640 | if (err) { |
| 641 | nr_calls--; |
| 642 | __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL); |
| 643 | pr_warn("%s: attempt to take down CPU %u failed\n", |
| 644 | __func__, cpu); |
| 645 | } |
| 646 | return err; |
| 647 | } |
| 648 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 649 | static int notify_dying(unsigned int cpu) |
| 650 | { |
| 651 | cpu_notify(CPU_DYING, cpu); |
| 652 | return 0; |
| 653 | } |
| 654 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 655 | /* Take this CPU down. */ |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 656 | static int take_cpu_down(void *_param) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | { |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 658 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 659 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 660 | int err, cpu = smp_processor_id(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 661 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 662 | /* Ensure this CPU doesn't handle any more interrupts. */ |
| 663 | err = __cpu_disable(); |
| 664 | if (err < 0) |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 665 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 666 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 667 | /* Invoke the former CPU_DYING callbacks */ |
| 668 | for (; st->state > target; st->state--) { |
| 669 | struct cpuhp_step *step = cpuhp_ap_states + st->state; |
| 670 | |
| 671 | cpuhp_invoke_callback(cpu, st->state, step->teardown); |
| 672 | } |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 673 | /* Give up timekeeping duties */ |
| 674 | tick_handover_do_timer(); |
Thomas Gleixner | 14e568e | 2013-01-31 12:11:14 +0000 | [diff] [blame] | 675 | /* Park the stopper thread */ |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 676 | stop_machine_park(cpu); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 677 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | } |
| 679 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 680 | static int takedown_cpu(unsigned int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | { |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 682 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 683 | |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 684 | /* |
| 685 | * By now we've cleared cpu_active_mask, wait for all preempt-disabled |
| 686 | * and RCU users of this state to go away such that all new such users |
| 687 | * will observe it. |
| 688 | * |
| 689 | * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might |
Paul E. McKenney | 779de6c | 2015-06-10 13:34:41 -0700 | [diff] [blame] | 690 | * not imply sync_sched(), so wait for both. |
Michael wang | 106dd5a | 2013-11-13 11:10:56 +0800 | [diff] [blame] | 691 | * |
| 692 | * Do sync before park smpboot threads to take care the rcu boost case. |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 693 | */ |
Paul E. McKenney | 779de6c | 2015-06-10 13:34:41 -0700 | [diff] [blame] | 694 | if (IS_ENABLED(CONFIG_PREEMPT)) |
| 695 | synchronize_rcu_mult(call_rcu, call_rcu_sched); |
| 696 | else |
| 697 | synchronize_rcu(); |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 698 | |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 699 | /* Park the hotplug thread */ |
| 700 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
| 701 | |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 702 | /* |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 703 | * Prevent irq alloc/free while the dying cpu reorganizes the |
| 704 | * interrupt affinities. |
| 705 | */ |
| 706 | irq_lock_sparse(); |
| 707 | |
| 708 | /* |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 709 | * So now all preempt/rcu users must observe !cpu_active(). |
| 710 | */ |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 711 | err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); |
Rusty Russell | 0432158 | 2008-07-28 12:16:29 -0500 | [diff] [blame] | 712 | if (err) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 713 | /* CPU didn't die: tell everyone. Can't complain. */ |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 714 | cpu_notify_nofail(CPU_DOWN_FAILED, cpu); |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 715 | irq_unlock_sparse(); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 716 | return err; |
Satoru Takeuchi | 8fa1d7d | 2006-10-28 10:38:57 -0700 | [diff] [blame] | 717 | } |
Rusty Russell | 0432158 | 2008-07-28 12:16:29 -0500 | [diff] [blame] | 718 | BUG_ON(cpu_online(cpu)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 719 | |
Peter Zijlstra | 48c5ccae | 2010-11-13 19:32:29 +0100 | [diff] [blame] | 720 | /* |
| 721 | * The migration_call() CPU_DYING callback will have removed all |
| 722 | * runnable tasks from the cpu, there's only the idle task left now |
| 723 | * that the migration thread is done doing the stop_machine thing. |
Peter Zijlstra | 51a96c7 | 2010-11-19 20:37:53 +0100 | [diff] [blame] | 724 | * |
| 725 | * Wait for the stop thread to go away. |
Peter Zijlstra | 48c5ccae | 2010-11-13 19:32:29 +0100 | [diff] [blame] | 726 | */ |
Paul E. McKenney | 528a25b | 2015-01-28 14:09:43 -0800 | [diff] [blame] | 727 | while (!per_cpu(cpu_dead_idle, cpu)) |
Peter Zijlstra | 51a96c7 | 2010-11-19 20:37:53 +0100 | [diff] [blame] | 728 | cpu_relax(); |
Paul E. McKenney | 528a25b | 2015-01-28 14:09:43 -0800 | [diff] [blame] | 729 | smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */ |
| 730 | per_cpu(cpu_dead_idle, cpu) = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 732 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
| 733 | irq_unlock_sparse(); |
| 734 | |
Preeti U Murthy | 345527b | 2015-03-30 14:59:19 +0530 | [diff] [blame] | 735 | hotplug_cpu__broadcast_tick_pull(cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 736 | /* This actually kills the CPU. */ |
| 737 | __cpu_die(cpu); |
| 738 | |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 739 | tick_cleanup_dead_cpu(cpu); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 740 | return 0; |
| 741 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 743 | static int notify_dead(unsigned int cpu) |
| 744 | { |
| 745 | cpu_notify_nofail(CPU_DEAD, cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 746 | check_for_tasks(cpu); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 747 | return 0; |
| 748 | } |
| 749 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 750 | #else |
| 751 | #define notify_down_prepare NULL |
| 752 | #define takedown_cpu NULL |
| 753 | #define notify_dead NULL |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 754 | #define notify_dying NULL |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 755 | #endif |
| 756 | |
| 757 | #ifdef CONFIG_HOTPLUG_CPU |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 758 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 759 | /* Requires cpu_add_remove_lock to be held */ |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 760 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
| 761 | enum cpuhp_state target) |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 762 | { |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 763 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 764 | int prev_state, ret = 0; |
| 765 | bool hasdied = false; |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 766 | |
| 767 | if (num_online_cpus() == 1) |
| 768 | return -EBUSY; |
| 769 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 770 | if (!cpu_present(cpu)) |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 771 | return -EINVAL; |
| 772 | |
| 773 | cpu_hotplug_begin(); |
| 774 | |
| 775 | cpuhp_tasks_frozen = tasks_frozen; |
| 776 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 777 | prev_state = st->state; |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 778 | st->target = target; |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 779 | /* |
| 780 | * If the current CPU state is in the range of the AP hotplug thread, |
| 781 | * then we need to kick the thread. |
| 782 | */ |
| 783 | if (st->state >= CPUHP_KICK_AP_THREAD) { |
| 784 | ret = cpuhp_kick_ap_work(cpu); |
| 785 | /* |
| 786 | * The AP side has done the error rollback already. Just |
| 787 | * return the error code.. |
| 788 | */ |
| 789 | if (ret) |
| 790 | goto out; |
| 791 | |
| 792 | /* |
| 793 | * We might have stopped still in the range of the AP hotplug |
| 794 | * thread. Nothing to do anymore. |
| 795 | */ |
| 796 | if (st->state >= CPUHP_KICK_AP_THREAD) |
| 797 | goto out; |
| 798 | } |
| 799 | /* |
| 800 | * The AP brought itself down below CPUHP_KICK_AP_THREAD. So we need |
| 801 | * to do the further cleanups. |
| 802 | */ |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 803 | ret = cpuhp_down_callbacks(cpu, st, cpuhp_bp_states, target); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 804 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 805 | hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE; |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 806 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 807 | cpu_hotplug_done(); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 808 | /* This post dead nonsense must die */ |
| 809 | if (!ret && hasdied) |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 810 | cpu_notify_nofail(CPU_POST_DEAD, cpu); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 811 | return ret; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 812 | } |
| 813 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 814 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 815 | { |
Heiko Carstens | 9ea09af | 2008-12-22 12:36:30 +0100 | [diff] [blame] | 816 | int err; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 817 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 818 | cpu_maps_update_begin(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 819 | |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 820 | if (cpu_hotplug_disabled) { |
| 821 | err = -EBUSY; |
| 822 | goto out; |
| 823 | } |
| 824 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 825 | err = _cpu_down(cpu, 0, target); |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 826 | |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 827 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 828 | cpu_maps_update_done(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 829 | return err; |
| 830 | } |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 831 | int cpu_down(unsigned int cpu) |
| 832 | { |
| 833 | return do_cpu_down(cpu, CPUHP_OFFLINE); |
| 834 | } |
Zhang Rui | b62b8ef | 2008-04-29 02:35:56 -0400 | [diff] [blame] | 835 | EXPORT_SYMBOL(cpu_down); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 836 | #endif /*CONFIG_HOTPLUG_CPU*/ |
| 837 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 838 | /** |
| 839 | * notify_cpu_starting(cpu) - call the CPU_STARTING notifiers |
| 840 | * @cpu: cpu that just started |
| 841 | * |
| 842 | * This function calls the cpu_chain notifiers with CPU_STARTING. |
| 843 | * It must be called by the arch code on the new cpu, before the new cpu |
| 844 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). |
| 845 | */ |
| 846 | void notify_cpu_starting(unsigned int cpu) |
| 847 | { |
| 848 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 849 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); |
| 850 | |
| 851 | while (st->state < target) { |
| 852 | struct cpuhp_step *step; |
| 853 | |
| 854 | st->state++; |
| 855 | step = cpuhp_ap_states + st->state; |
| 856 | cpuhp_invoke_callback(cpu, st->state, step->startup); |
| 857 | } |
| 858 | } |
| 859 | |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 860 | /* |
| 861 | * Called from the idle task. We need to set active here, so we can kick off |
| 862 | * the stopper thread. |
| 863 | */ |
| 864 | static int cpuhp_set_cpu_active(unsigned int cpu) |
| 865 | { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 866 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 867 | |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 868 | /* The cpu is marked online, set it active now */ |
| 869 | set_cpu_active(cpu, true); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 870 | /* Unpark the stopper thread and the hotplug thread */ |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 871 | stop_machine_unpark(cpu); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 872 | kthread_unpark(st->thread); |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 873 | return 0; |
| 874 | } |
| 875 | |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 876 | /* Requires cpu_add_remove_lock to be held */ |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 877 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 878 | { |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 879 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
Suresh Siddha | 3bb5d2e | 2012-04-20 17:08:50 -0700 | [diff] [blame] | 880 | struct task_struct *idle; |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 881 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 882 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 883 | cpu_hotplug_begin(); |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 884 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 885 | if (!cpu_present(cpu)) { |
Yasuaki Ishimatsu | 5e5041f | 2012-10-23 01:30:54 +0200 | [diff] [blame] | 886 | ret = -EINVAL; |
| 887 | goto out; |
| 888 | } |
| 889 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 890 | /* |
| 891 | * The caller of do_cpu_up might have raced with another |
| 892 | * caller. Ignore it for now. |
| 893 | */ |
| 894 | if (st->state >= target) |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 895 | goto out; |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 896 | |
| 897 | if (st->state == CPUHP_OFFLINE) { |
| 898 | /* Let it fail before we try to bring the cpu up */ |
| 899 | idle = idle_thread_get(cpu); |
| 900 | if (IS_ERR(idle)) { |
| 901 | ret = PTR_ERR(idle); |
| 902 | goto out; |
| 903 | } |
Suresh Siddha | 3bb5d2e | 2012-04-20 17:08:50 -0700 | [diff] [blame] | 904 | } |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 905 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 906 | cpuhp_tasks_frozen = tasks_frozen; |
| 907 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 908 | st->target = target; |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 909 | /* |
| 910 | * If the current CPU state is in the range of the AP hotplug thread, |
| 911 | * then we need to kick the thread once more. |
| 912 | */ |
| 913 | if (st->state >= CPUHP_KICK_AP_THREAD) { |
| 914 | ret = cpuhp_kick_ap_work(cpu); |
| 915 | /* |
| 916 | * The AP side has done the error rollback already. Just |
| 917 | * return the error code.. |
| 918 | */ |
| 919 | if (ret) |
| 920 | goto out; |
| 921 | } |
| 922 | |
| 923 | /* |
| 924 | * Try to reach the target state. We max out on the BP at |
| 925 | * CPUHP_KICK_AP_THREAD. After that the AP hotplug thread is |
| 926 | * responsible for bringing it up to the target state. |
| 927 | */ |
| 928 | target = min((int)target, CPUHP_KICK_AP_THREAD); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 929 | ret = cpuhp_up_callbacks(cpu, st, cpuhp_bp_states, target); |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 930 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 931 | cpu_hotplug_done(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 932 | return ret; |
| 933 | } |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 934 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 935 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 936 | { |
| 937 | int err = 0; |
minskey guo | cf23422 | 2010-05-24 14:32:41 -0700 | [diff] [blame] | 938 | |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 939 | if (!cpu_possible(cpu)) { |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 940 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
| 941 | cpu); |
Chen Gong | 87d5e023 | 2010-03-05 13:42:38 -0800 | [diff] [blame] | 942 | #if defined(CONFIG_IA64) |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 943 | pr_err("please check additional_cpus= boot parameter\n"); |
KAMEZAWA Hiroyuki | 73e753a | 2007-10-18 23:40:47 -0700 | [diff] [blame] | 944 | #endif |
| 945 | return -EINVAL; |
| 946 | } |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 947 | |
Toshi Kani | 01b0f19 | 2013-11-12 15:07:25 -0800 | [diff] [blame] | 948 | err = try_online_node(cpu_to_node(cpu)); |
| 949 | if (err) |
| 950 | return err; |
minskey guo | cf23422 | 2010-05-24 14:32:41 -0700 | [diff] [blame] | 951 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 952 | cpu_maps_update_begin(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 953 | |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 954 | if (cpu_hotplug_disabled) { |
| 955 | err = -EBUSY; |
| 956 | goto out; |
| 957 | } |
| 958 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 959 | err = _cpu_up(cpu, 0, target); |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 960 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 961 | cpu_maps_update_done(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 962 | return err; |
| 963 | } |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 964 | |
| 965 | int cpu_up(unsigned int cpu) |
| 966 | { |
| 967 | return do_cpu_up(cpu, CPUHP_ONLINE); |
| 968 | } |
Paul E. McKenney | a513f6b | 2011-12-11 21:54:45 -0800 | [diff] [blame] | 969 | EXPORT_SYMBOL_GPL(cpu_up); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 970 | |
Rafael J. Wysocki | f3de4be | 2007-08-30 23:56:29 -0700 | [diff] [blame] | 971 | #ifdef CONFIG_PM_SLEEP_SMP |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 972 | static cpumask_var_t frozen_cpus; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 973 | |
| 974 | int disable_nonboot_cpus(void) |
| 975 | { |
Rafael J. Wysocki | e9a5f42 | 2010-05-27 22:16:22 +0200 | [diff] [blame] | 976 | int cpu, first_cpu, error = 0; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 977 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 978 | cpu_maps_update_begin(); |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 979 | first_cpu = cpumask_first(cpu_online_mask); |
Xiaotian Feng | 9ee349a | 2009-12-16 18:04:32 +0100 | [diff] [blame] | 980 | /* |
| 981 | * We take down all of the non-boot CPUs in one shot to avoid races |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 982 | * with the userspace trying to use the CPU hotplug at the same time |
| 983 | */ |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 984 | cpumask_clear(frozen_cpus); |
Peter Zijlstra | 6ad4c18 | 2009-11-25 13:31:39 +0100 | [diff] [blame] | 985 | |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 986 | pr_info("Disabling non-boot CPUs ...\n"); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 987 | for_each_online_cpu(cpu) { |
| 988 | if (cpu == first_cpu) |
| 989 | continue; |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 990 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 991 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 992 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
Mike Travis | feae320 | 2009-11-17 18:22:13 -0600 | [diff] [blame] | 993 | if (!error) |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 994 | cpumask_set_cpu(cpu, frozen_cpus); |
Mike Travis | feae320 | 2009-11-17 18:22:13 -0600 | [diff] [blame] | 995 | else { |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 996 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 997 | break; |
| 998 | } |
| 999 | } |
Joseph Cihula | 86886e5 | 2009-06-30 19:31:07 -0700 | [diff] [blame] | 1000 | |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1001 | if (!error) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1002 | BUG_ON(num_online_cpus() > 1); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1003 | else |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1004 | pr_err("Non-boot CPUs are not disabled\n"); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1005 | |
| 1006 | /* |
| 1007 | * Make sure the CPUs won't be enabled by someone else. We need to do |
| 1008 | * this even in case of failure as all disable_nonboot_cpus() users are |
| 1009 | * supposed to do enable_nonboot_cpus() on the failure path. |
| 1010 | */ |
| 1011 | cpu_hotplug_disabled++; |
| 1012 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1013 | cpu_maps_update_done(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1014 | return error; |
| 1015 | } |
| 1016 | |
Suresh Siddha | d0af9ee | 2009-08-19 18:05:36 -0700 | [diff] [blame] | 1017 | void __weak arch_enable_nonboot_cpus_begin(void) |
| 1018 | { |
| 1019 | } |
| 1020 | |
| 1021 | void __weak arch_enable_nonboot_cpus_end(void) |
| 1022 | { |
| 1023 | } |
| 1024 | |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 1025 | void enable_nonboot_cpus(void) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1026 | { |
| 1027 | int cpu, error; |
| 1028 | |
| 1029 | /* Allow everyone to use the CPU hotplug again */ |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1030 | cpu_maps_update_begin(); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1031 | WARN_ON(--cpu_hotplug_disabled < 0); |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1032 | if (cpumask_empty(frozen_cpus)) |
Rafael J. Wysocki | 1d64b9c | 2007-04-01 23:49:49 -0700 | [diff] [blame] | 1033 | goto out; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1034 | |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1035 | pr_info("Enabling non-boot CPUs ...\n"); |
Suresh Siddha | d0af9ee | 2009-08-19 18:05:36 -0700 | [diff] [blame] | 1036 | |
| 1037 | arch_enable_nonboot_cpus_begin(); |
| 1038 | |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1039 | for_each_cpu(cpu, frozen_cpus) { |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 1040 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1041 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 1042 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1043 | if (!error) { |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1044 | pr_info("CPU%d is up\n", cpu); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1045 | continue; |
| 1046 | } |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1047 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1048 | } |
Suresh Siddha | d0af9ee | 2009-08-19 18:05:36 -0700 | [diff] [blame] | 1049 | |
| 1050 | arch_enable_nonboot_cpus_end(); |
| 1051 | |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1052 | cpumask_clear(frozen_cpus); |
Rafael J. Wysocki | 1d64b9c | 2007-04-01 23:49:49 -0700 | [diff] [blame] | 1053 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1054 | cpu_maps_update_done(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1055 | } |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1056 | |
Fenghua Yu | d7268a3 | 2011-11-15 21:59:31 +0100 | [diff] [blame] | 1057 | static int __init alloc_frozen_cpus(void) |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1058 | { |
| 1059 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) |
| 1060 | return -ENOMEM; |
| 1061 | return 0; |
| 1062 | } |
| 1063 | core_initcall(alloc_frozen_cpus); |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1064 | |
| 1065 | /* |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1066 | * When callbacks for CPU hotplug notifications are being executed, we must |
| 1067 | * ensure that the state of the system with respect to the tasks being frozen |
| 1068 | * or not, as reported by the notification, remains unchanged *throughout the |
| 1069 | * duration* of the execution of the callbacks. |
| 1070 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. |
| 1071 | * |
| 1072 | * This synchronization is implemented by mutually excluding regular CPU |
| 1073 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ |
| 1074 | * Hibernate notifications. |
| 1075 | */ |
| 1076 | static int |
| 1077 | cpu_hotplug_pm_callback(struct notifier_block *nb, |
| 1078 | unsigned long action, void *ptr) |
| 1079 | { |
| 1080 | switch (action) { |
| 1081 | |
| 1082 | case PM_SUSPEND_PREPARE: |
| 1083 | case PM_HIBERNATION_PREPARE: |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 1084 | cpu_hotplug_disable(); |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1085 | break; |
| 1086 | |
| 1087 | case PM_POST_SUSPEND: |
| 1088 | case PM_POST_HIBERNATION: |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 1089 | cpu_hotplug_enable(); |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1090 | break; |
| 1091 | |
| 1092 | default: |
| 1093 | return NOTIFY_DONE; |
| 1094 | } |
| 1095 | |
| 1096 | return NOTIFY_OK; |
| 1097 | } |
| 1098 | |
| 1099 | |
Fenghua Yu | d7268a3 | 2011-11-15 21:59:31 +0100 | [diff] [blame] | 1100 | static int __init cpu_hotplug_pm_sync_init(void) |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1101 | { |
Fenghua Yu | 6e32d47 | 2012-11-13 11:32:43 -0800 | [diff] [blame] | 1102 | /* |
| 1103 | * cpu_hotplug_pm_callback has higher priority than x86 |
| 1104 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback |
| 1105 | * to disable cpu hotplug to avoid cpu hotplug race. |
| 1106 | */ |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1107 | pm_notifier(cpu_hotplug_pm_callback, 0); |
| 1108 | return 0; |
| 1109 | } |
| 1110 | core_initcall(cpu_hotplug_pm_sync_init); |
| 1111 | |
Rafael J. Wysocki | f3de4be | 2007-08-30 23:56:29 -0700 | [diff] [blame] | 1112 | #endif /* CONFIG_PM_SLEEP_SMP */ |
Max Krasnyansky | 68f4f1e | 2008-05-29 11:17:02 -0700 | [diff] [blame] | 1113 | |
| 1114 | #endif /* CONFIG_SMP */ |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 1115 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1116 | /* Boot processor state steps */ |
| 1117 | static struct cpuhp_step cpuhp_bp_states[] = { |
| 1118 | [CPUHP_OFFLINE] = { |
| 1119 | .name = "offline", |
| 1120 | .startup = NULL, |
| 1121 | .teardown = NULL, |
| 1122 | }, |
| 1123 | #ifdef CONFIG_SMP |
| 1124 | [CPUHP_CREATE_THREADS]= { |
| 1125 | .name = "threads:create", |
| 1126 | .startup = smpboot_create_threads, |
| 1127 | .teardown = NULL, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1128 | .cant_stop = true, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1129 | }, |
| 1130 | [CPUHP_NOTIFY_PREPARE] = { |
| 1131 | .name = "notify:prepare", |
| 1132 | .startup = notify_prepare, |
| 1133 | .teardown = notify_dead, |
| 1134 | .skip_onerr = true, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1135 | .cant_stop = true, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1136 | }, |
| 1137 | [CPUHP_BRINGUP_CPU] = { |
| 1138 | .name = "cpu:bringup", |
| 1139 | .startup = bringup_cpu, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1140 | .teardown = NULL, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1141 | .cant_stop = true, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1142 | }, |
| 1143 | [CPUHP_TEARDOWN_CPU] = { |
| 1144 | .name = "cpu:teardown", |
| 1145 | .startup = NULL, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1146 | .teardown = takedown_cpu, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1147 | .cant_stop = true, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1148 | }, |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 1149 | [CPUHP_CPU_SET_ACTIVE] = { |
| 1150 | .name = "cpu:active", |
| 1151 | .startup = cpuhp_set_cpu_active, |
| 1152 | .teardown = NULL, |
| 1153 | }, |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1154 | [CPUHP_KICK_AP_THREAD] = { |
| 1155 | .name = "cpuhp:kickthread", |
| 1156 | .startup = cpuhp_kick_ap_work, |
| 1157 | .teardown = cpuhp_kick_ap_work, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1158 | }, |
| 1159 | #endif |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1160 | [CPUHP_BP_ONLINE] = { |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1161 | .name = "online", |
| 1162 | .startup = NULL, |
| 1163 | .teardown = NULL, |
| 1164 | }, |
| 1165 | }; |
| 1166 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1167 | /* Application processor state steps */ |
| 1168 | static struct cpuhp_step cpuhp_ap_states[] = { |
| 1169 | #ifdef CONFIG_SMP |
| 1170 | [CPUHP_AP_NOTIFY_STARTING] = { |
| 1171 | .name = "notify:starting", |
| 1172 | .startup = notify_starting, |
| 1173 | .teardown = notify_dying, |
| 1174 | .skip_onerr = true, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1175 | .cant_stop = true, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1176 | }, |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1177 | [CPUHP_AP_SMPBOOT_THREADS] = { |
| 1178 | .name = "smpboot:threads", |
| 1179 | .startup = smpboot_unpark_threads, |
| 1180 | .teardown = smpboot_park_threads, |
| 1181 | }, |
| 1182 | [CPUHP_AP_NOTIFY_ONLINE] = { |
| 1183 | .name = "notify:online", |
| 1184 | .startup = notify_online, |
| 1185 | .teardown = notify_down_prepare, |
| 1186 | }, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1187 | #endif |
| 1188 | [CPUHP_ONLINE] = { |
| 1189 | .name = "online", |
| 1190 | .startup = NULL, |
| 1191 | .teardown = NULL, |
| 1192 | }, |
| 1193 | }; |
| 1194 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1195 | /* Sanity check for callbacks */ |
| 1196 | static int cpuhp_cb_check(enum cpuhp_state state) |
| 1197 | { |
| 1198 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) |
| 1199 | return -EINVAL; |
| 1200 | return 0; |
| 1201 | } |
| 1202 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1203 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
| 1204 | { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1205 | if (state >= CPUHP_AP_OFFLINE && state <= CPUHP_AP_ONLINE) |
| 1206 | return true; |
| 1207 | return state > CPUHP_BP_ONLINE; |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1208 | } |
| 1209 | |
| 1210 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
| 1211 | { |
| 1212 | struct cpuhp_step *sp; |
| 1213 | |
| 1214 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; |
| 1215 | return sp + state; |
| 1216 | } |
| 1217 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1218 | static void cpuhp_store_callbacks(enum cpuhp_state state, |
| 1219 | const char *name, |
| 1220 | int (*startup)(unsigned int cpu), |
| 1221 | int (*teardown)(unsigned int cpu)) |
| 1222 | { |
| 1223 | /* (Un)Install the callbacks for further cpu hotplug operations */ |
| 1224 | struct cpuhp_step *sp; |
| 1225 | |
| 1226 | mutex_lock(&cpuhp_state_mutex); |
| 1227 | sp = cpuhp_get_step(state); |
| 1228 | sp->startup = startup; |
| 1229 | sp->teardown = teardown; |
| 1230 | sp->name = name; |
| 1231 | mutex_unlock(&cpuhp_state_mutex); |
| 1232 | } |
| 1233 | |
| 1234 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) |
| 1235 | { |
| 1236 | return cpuhp_get_step(state)->teardown; |
| 1237 | } |
| 1238 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1239 | /* |
| 1240 | * Call the startup/teardown function for a step either on the AP or |
| 1241 | * on the current CPU. |
| 1242 | */ |
| 1243 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, |
| 1244 | int (*cb)(unsigned int), bool bringup) |
| 1245 | { |
| 1246 | int ret; |
| 1247 | |
| 1248 | if (!cb) |
| 1249 | return 0; |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1250 | /* |
| 1251 | * The non AP bound callbacks can fail on bringup. On teardown |
| 1252 | * e.g. module removal we crash for now. |
| 1253 | */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1254 | #ifdef CONFIG_SMP |
| 1255 | if (cpuhp_is_ap_state(state)) |
| 1256 | ret = cpuhp_invoke_ap_callback(cpu, state, cb); |
| 1257 | else |
| 1258 | ret = cpuhp_invoke_callback(cpu, state, cb); |
| 1259 | #else |
| 1260 | ret = cpuhp_invoke_callback(cpu, state, cb); |
| 1261 | #endif |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1262 | BUG_ON(ret && !bringup); |
| 1263 | return ret; |
| 1264 | } |
| 1265 | |
| 1266 | /* |
| 1267 | * Called from __cpuhp_setup_state on a recoverable failure. |
| 1268 | * |
| 1269 | * Note: The teardown callbacks for rollback are not allowed to fail! |
| 1270 | */ |
| 1271 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, |
| 1272 | int (*teardown)(unsigned int cpu)) |
| 1273 | { |
| 1274 | int cpu; |
| 1275 | |
| 1276 | if (!teardown) |
| 1277 | return; |
| 1278 | |
| 1279 | /* Roll back the already executed steps on the other cpus */ |
| 1280 | for_each_present_cpu(cpu) { |
| 1281 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1282 | int cpustate = st->state; |
| 1283 | |
| 1284 | if (cpu >= failedcpu) |
| 1285 | break; |
| 1286 | |
| 1287 | /* Did we invoke the startup call on that cpu ? */ |
| 1288 | if (cpustate >= state) |
| 1289 | cpuhp_issue_call(cpu, state, teardown, false); |
| 1290 | } |
| 1291 | } |
| 1292 | |
| 1293 | /* |
| 1294 | * Returns a free for dynamic slot assignment of the Online state. The states |
| 1295 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified |
| 1296 | * by having no name assigned. |
| 1297 | */ |
| 1298 | static int cpuhp_reserve_state(enum cpuhp_state state) |
| 1299 | { |
| 1300 | enum cpuhp_state i; |
| 1301 | |
| 1302 | mutex_lock(&cpuhp_state_mutex); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1303 | for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) { |
| 1304 | if (cpuhp_ap_states[i].name) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1305 | continue; |
| 1306 | |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1307 | cpuhp_ap_states[i].name = "Reserved"; |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1308 | mutex_unlock(&cpuhp_state_mutex); |
| 1309 | return i; |
| 1310 | } |
| 1311 | mutex_unlock(&cpuhp_state_mutex); |
| 1312 | WARN(1, "No more dynamic states available for CPU hotplug\n"); |
| 1313 | return -ENOSPC; |
| 1314 | } |
| 1315 | |
| 1316 | /** |
| 1317 | * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state |
| 1318 | * @state: The state to setup |
| 1319 | * @invoke: If true, the startup function is invoked for cpus where |
| 1320 | * cpu state >= @state |
| 1321 | * @startup: startup callback function |
| 1322 | * @teardown: teardown callback function |
| 1323 | * |
| 1324 | * Returns 0 if successful, otherwise a proper error code |
| 1325 | */ |
| 1326 | int __cpuhp_setup_state(enum cpuhp_state state, |
| 1327 | const char *name, bool invoke, |
| 1328 | int (*startup)(unsigned int cpu), |
| 1329 | int (*teardown)(unsigned int cpu)) |
| 1330 | { |
| 1331 | int cpu, ret = 0; |
| 1332 | int dyn_state = 0; |
| 1333 | |
| 1334 | if (cpuhp_cb_check(state) || !name) |
| 1335 | return -EINVAL; |
| 1336 | |
| 1337 | get_online_cpus(); |
| 1338 | |
| 1339 | /* currently assignments for the ONLINE state are possible */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame^] | 1340 | if (state == CPUHP_AP_ONLINE_DYN) { |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1341 | dyn_state = 1; |
| 1342 | ret = cpuhp_reserve_state(state); |
| 1343 | if (ret < 0) |
| 1344 | goto out; |
| 1345 | state = ret; |
| 1346 | } |
| 1347 | |
| 1348 | cpuhp_store_callbacks(state, name, startup, teardown); |
| 1349 | |
| 1350 | if (!invoke || !startup) |
| 1351 | goto out; |
| 1352 | |
| 1353 | /* |
| 1354 | * Try to call the startup callback for each present cpu |
| 1355 | * depending on the hotplug state of the cpu. |
| 1356 | */ |
| 1357 | for_each_present_cpu(cpu) { |
| 1358 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1359 | int cpustate = st->state; |
| 1360 | |
| 1361 | if (cpustate < state) |
| 1362 | continue; |
| 1363 | |
| 1364 | ret = cpuhp_issue_call(cpu, state, startup, true); |
| 1365 | if (ret) { |
| 1366 | cpuhp_rollback_install(cpu, state, teardown); |
| 1367 | cpuhp_store_callbacks(state, NULL, NULL, NULL); |
| 1368 | goto out; |
| 1369 | } |
| 1370 | } |
| 1371 | out: |
| 1372 | put_online_cpus(); |
| 1373 | if (!ret && dyn_state) |
| 1374 | return state; |
| 1375 | return ret; |
| 1376 | } |
| 1377 | EXPORT_SYMBOL(__cpuhp_setup_state); |
| 1378 | |
| 1379 | /** |
| 1380 | * __cpuhp_remove_state - Remove the callbacks for an hotplug machine state |
| 1381 | * @state: The state to remove |
| 1382 | * @invoke: If true, the teardown function is invoked for cpus where |
| 1383 | * cpu state >= @state |
| 1384 | * |
| 1385 | * The teardown callback is currently not allowed to fail. Think |
| 1386 | * about module removal! |
| 1387 | */ |
| 1388 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) |
| 1389 | { |
| 1390 | int (*teardown)(unsigned int cpu) = cpuhp_get_teardown_cb(state); |
| 1391 | int cpu; |
| 1392 | |
| 1393 | BUG_ON(cpuhp_cb_check(state)); |
| 1394 | |
| 1395 | get_online_cpus(); |
| 1396 | |
| 1397 | if (!invoke || !teardown) |
| 1398 | goto remove; |
| 1399 | |
| 1400 | /* |
| 1401 | * Call the teardown callback for each present cpu depending |
| 1402 | * on the hotplug state of the cpu. This function is not |
| 1403 | * allowed to fail currently! |
| 1404 | */ |
| 1405 | for_each_present_cpu(cpu) { |
| 1406 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1407 | int cpustate = st->state; |
| 1408 | |
| 1409 | if (cpustate >= state) |
| 1410 | cpuhp_issue_call(cpu, state, teardown, false); |
| 1411 | } |
| 1412 | remove: |
| 1413 | cpuhp_store_callbacks(state, NULL, NULL, NULL); |
| 1414 | put_online_cpus(); |
| 1415 | } |
| 1416 | EXPORT_SYMBOL(__cpuhp_remove_state); |
| 1417 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1418 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
| 1419 | static ssize_t show_cpuhp_state(struct device *dev, |
| 1420 | struct device_attribute *attr, char *buf) |
| 1421 | { |
| 1422 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1423 | |
| 1424 | return sprintf(buf, "%d\n", st->state); |
| 1425 | } |
| 1426 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); |
| 1427 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1428 | static ssize_t write_cpuhp_target(struct device *dev, |
| 1429 | struct device_attribute *attr, |
| 1430 | const char *buf, size_t count) |
| 1431 | { |
| 1432 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1433 | struct cpuhp_step *sp; |
| 1434 | int target, ret; |
| 1435 | |
| 1436 | ret = kstrtoint(buf, 10, &target); |
| 1437 | if (ret) |
| 1438 | return ret; |
| 1439 | |
| 1440 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL |
| 1441 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) |
| 1442 | return -EINVAL; |
| 1443 | #else |
| 1444 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) |
| 1445 | return -EINVAL; |
| 1446 | #endif |
| 1447 | |
| 1448 | ret = lock_device_hotplug_sysfs(); |
| 1449 | if (ret) |
| 1450 | return ret; |
| 1451 | |
| 1452 | mutex_lock(&cpuhp_state_mutex); |
| 1453 | sp = cpuhp_get_step(target); |
| 1454 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; |
| 1455 | mutex_unlock(&cpuhp_state_mutex); |
| 1456 | if (ret) |
| 1457 | return ret; |
| 1458 | |
| 1459 | if (st->state < target) |
| 1460 | ret = do_cpu_up(dev->id, target); |
| 1461 | else |
| 1462 | ret = do_cpu_down(dev->id, target); |
| 1463 | |
| 1464 | unlock_device_hotplug(); |
| 1465 | return ret ? ret : count; |
| 1466 | } |
| 1467 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1468 | static ssize_t show_cpuhp_target(struct device *dev, |
| 1469 | struct device_attribute *attr, char *buf) |
| 1470 | { |
| 1471 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1472 | |
| 1473 | return sprintf(buf, "%d\n", st->target); |
| 1474 | } |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1475 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1476 | |
| 1477 | static struct attribute *cpuhp_cpu_attrs[] = { |
| 1478 | &dev_attr_state.attr, |
| 1479 | &dev_attr_target.attr, |
| 1480 | NULL |
| 1481 | }; |
| 1482 | |
| 1483 | static struct attribute_group cpuhp_cpu_attr_group = { |
| 1484 | .attrs = cpuhp_cpu_attrs, |
| 1485 | .name = "hotplug", |
| 1486 | NULL |
| 1487 | }; |
| 1488 | |
| 1489 | static ssize_t show_cpuhp_states(struct device *dev, |
| 1490 | struct device_attribute *attr, char *buf) |
| 1491 | { |
| 1492 | ssize_t cur, res = 0; |
| 1493 | int i; |
| 1494 | |
| 1495 | mutex_lock(&cpuhp_state_mutex); |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1496 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1497 | struct cpuhp_step *sp = cpuhp_get_step(i); |
| 1498 | |
| 1499 | if (sp->name) { |
| 1500 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); |
| 1501 | buf += cur; |
| 1502 | res += cur; |
| 1503 | } |
| 1504 | } |
| 1505 | mutex_unlock(&cpuhp_state_mutex); |
| 1506 | return res; |
| 1507 | } |
| 1508 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); |
| 1509 | |
| 1510 | static struct attribute *cpuhp_cpu_root_attrs[] = { |
| 1511 | &dev_attr_states.attr, |
| 1512 | NULL |
| 1513 | }; |
| 1514 | |
| 1515 | static struct attribute_group cpuhp_cpu_root_attr_group = { |
| 1516 | .attrs = cpuhp_cpu_root_attrs, |
| 1517 | .name = "hotplug", |
| 1518 | NULL |
| 1519 | }; |
| 1520 | |
| 1521 | static int __init cpuhp_sysfs_init(void) |
| 1522 | { |
| 1523 | int cpu, ret; |
| 1524 | |
| 1525 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
| 1526 | &cpuhp_cpu_root_attr_group); |
| 1527 | if (ret) |
| 1528 | return ret; |
| 1529 | |
| 1530 | for_each_possible_cpu(cpu) { |
| 1531 | struct device *dev = get_cpu_device(cpu); |
| 1532 | |
| 1533 | if (!dev) |
| 1534 | continue; |
| 1535 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); |
| 1536 | if (ret) |
| 1537 | return ret; |
| 1538 | } |
| 1539 | return 0; |
| 1540 | } |
| 1541 | device_initcall(cpuhp_sysfs_init); |
| 1542 | #endif |
| 1543 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1544 | /* |
| 1545 | * cpu_bit_bitmap[] is a special, "compressed" data structure that |
| 1546 | * represents all NR_CPUS bits binary values of 1<<nr. |
| 1547 | * |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1548 | * It is used by cpumask_of() to get a constant address to a CPU |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1549 | * mask value that has a single bit set only. |
| 1550 | */ |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 1551 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1552 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
Michael Rodriguez | 4d51985 | 2011-03-22 16:34:07 -0700 | [diff] [blame] | 1553 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1554 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
| 1555 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) |
| 1556 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 1557 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1558 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 1559 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1560 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), |
| 1561 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), |
| 1562 | #if BITS_PER_LONG > 32 |
| 1563 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), |
| 1564 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 1565 | #endif |
| 1566 | }; |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 1567 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
Rusty Russell | 2d3854a | 2008-11-05 13:39:10 +1100 | [diff] [blame] | 1568 | |
| 1569 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; |
| 1570 | EXPORT_SYMBOL(cpu_all_bits); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 1571 | |
| 1572 | #ifdef CONFIG_INIT_ALL_POSSIBLE |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 1573 | struct cpumask __cpu_possible_mask __read_mostly |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 1574 | = {CPU_BITS_ALL}; |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 1575 | #else |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 1576 | struct cpumask __cpu_possible_mask __read_mostly; |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 1577 | #endif |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 1578 | EXPORT_SYMBOL(__cpu_possible_mask); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 1579 | |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 1580 | struct cpumask __cpu_online_mask __read_mostly; |
| 1581 | EXPORT_SYMBOL(__cpu_online_mask); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 1582 | |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 1583 | struct cpumask __cpu_present_mask __read_mostly; |
| 1584 | EXPORT_SYMBOL(__cpu_present_mask); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 1585 | |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 1586 | struct cpumask __cpu_active_mask __read_mostly; |
| 1587 | EXPORT_SYMBOL(__cpu_active_mask); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 1588 | |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 1589 | void init_cpu_present(const struct cpumask *src) |
| 1590 | { |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 1591 | cpumask_copy(&__cpu_present_mask, src); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 1592 | } |
| 1593 | |
| 1594 | void init_cpu_possible(const struct cpumask *src) |
| 1595 | { |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 1596 | cpumask_copy(&__cpu_possible_mask, src); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 1597 | } |
| 1598 | |
| 1599 | void init_cpu_online(const struct cpumask *src) |
| 1600 | { |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 1601 | cpumask_copy(&__cpu_online_mask, src); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 1602 | } |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1603 | |
| 1604 | /* |
| 1605 | * Activate the first processor. |
| 1606 | */ |
| 1607 | void __init boot_cpu_init(void) |
| 1608 | { |
| 1609 | int cpu = smp_processor_id(); |
| 1610 | |
| 1611 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ |
| 1612 | set_cpu_online(cpu, true); |
| 1613 | set_cpu_active(cpu, true); |
| 1614 | set_cpu_present(cpu, true); |
| 1615 | set_cpu_possible(cpu, true); |
| 1616 | } |
| 1617 | |
| 1618 | /* |
| 1619 | * Must be called _AFTER_ setting up the per_cpu areas |
| 1620 | */ |
| 1621 | void __init boot_cpu_state_init(void) |
| 1622 | { |
| 1623 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; |
| 1624 | } |