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> |
Thomas Gleixner | a3c901b | 2018-11-25 19:33:39 +0100 | [diff] [blame] | 11 | #include <linux/sched/smt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/unistd.h> |
| 13 | #include <linux/cpu.h> |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 14 | #include <linux/oom.h> |
| 15 | #include <linux/rcupdate.h> |
Paul Gortmaker | 9984de1 | 2011-05-23 14:51:41 -0400 | [diff] [blame] | 16 | #include <linux/export.h> |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 17 | #include <linux/bug.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 18 | #include <linux/kthread.h> |
| 19 | #include <linux/stop_machine.h> |
Ingo Molnar | 81615b6 | 2006-06-26 00:24:32 -0700 | [diff] [blame] | 20 | #include <linux/mutex.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 21 | #include <linux/gfp.h> |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 22 | #include <linux/suspend.h> |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 23 | #include <linux/lockdep.h> |
Preeti U Murthy | 345527b | 2015-03-30 14:59:19 +0530 | [diff] [blame] | 24 | #include <linux/tick.h> |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 25 | #include <linux/irq.h> |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 26 | #include <linux/smpboot.h> |
Richard Weinberger | e6d4989 | 2016-08-18 14:57:17 +0200 | [diff] [blame] | 27 | #include <linux/relay.h> |
Sebastian Andrzej Siewior | 6731d4f | 2016-08-23 14:53:19 +0200 | [diff] [blame] | 28 | #include <linux/slab.h> |
Maria Yu | e90f8e1 | 2017-09-21 11:30:53 +0800 | [diff] [blame] | 29 | #include <linux/highmem.h> |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 30 | |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 31 | #include <trace/events/power.h> |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 32 | #define CREATE_TRACE_POINTS |
| 33 | #include <trace/events/cpuhp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 35 | #include "smpboot.h" |
| 36 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 37 | /** |
| 38 | * cpuhp_cpu_state - Per cpu hotplug state storage |
| 39 | * @state: The current cpu state |
| 40 | * @target: The target state |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 41 | * @thread: Pointer to the hotplug thread |
| 42 | * @should_run: Thread should execute |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 43 | * @rollback: Perform a rollback |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 44 | * @single: Single callback invocation |
| 45 | * @bringup: Single callback bringup or teardown selector |
| 46 | * @cb_state: The state for a single callback (install/uninstall) |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 47 | * @result: Result of the operation |
| 48 | * @done: Signal completion to the issuer of the task |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 49 | */ |
| 50 | struct cpuhp_cpu_state { |
| 51 | enum cpuhp_state state; |
| 52 | enum cpuhp_state target; |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 53 | #ifdef CONFIG_SMP |
| 54 | struct task_struct *thread; |
| 55 | bool should_run; |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 56 | bool rollback; |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 57 | bool single; |
| 58 | bool bringup; |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 59 | bool booted_once; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 60 | struct hlist_node *node; |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 61 | enum cpuhp_state cb_state; |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 62 | int result; |
| 63 | struct completion done; |
| 64 | #endif |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 65 | }; |
| 66 | |
| 67 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); |
| 68 | |
Thomas Gleixner | c198e22 | 2017-05-24 10:15:43 +0200 | [diff] [blame] | 69 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
| 70 | static struct lock_class_key cpuhp_state_key; |
| 71 | static struct lockdep_map cpuhp_state_lock_map = |
| 72 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state", &cpuhp_state_key); |
| 73 | #endif |
| 74 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 75 | /** |
| 76 | * cpuhp_step - Hotplug state machine step |
| 77 | * @name: Name of the step |
| 78 | * @startup: Startup function of the step |
| 79 | * @teardown: Teardown function of the step |
| 80 | * @skip_onerr: Do not invoke the functions on error rollback |
| 81 | * Will go away once the notifiers are gone |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 82 | * @cant_stop: Bringup/teardown can't be stopped at this step |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 83 | */ |
| 84 | struct cpuhp_step { |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 85 | const char *name; |
| 86 | union { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 87 | int (*single)(unsigned int cpu); |
| 88 | int (*multi)(unsigned int cpu, |
| 89 | struct hlist_node *node); |
| 90 | } startup; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 91 | union { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 92 | int (*single)(unsigned int cpu); |
| 93 | int (*multi)(unsigned int cpu, |
| 94 | struct hlist_node *node); |
| 95 | } teardown; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 96 | struct hlist_head list; |
| 97 | bool skip_onerr; |
| 98 | bool cant_stop; |
| 99 | bool multi_instance; |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 100 | }; |
| 101 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 102 | static DEFINE_MUTEX(cpuhp_state_mutex); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 103 | static struct cpuhp_step cpuhp_bp_states[]; |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 104 | static struct cpuhp_step cpuhp_ap_states[]; |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 105 | |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 106 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
| 107 | { |
| 108 | /* |
| 109 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation |
| 110 | * purposes as that state is handled explicitly in cpu_down. |
| 111 | */ |
| 112 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; |
| 113 | } |
| 114 | |
| 115 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
| 116 | { |
| 117 | struct cpuhp_step *sp; |
| 118 | |
| 119 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; |
| 120 | return sp + state; |
| 121 | } |
| 122 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 123 | /** |
| 124 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state |
| 125 | * @cpu: The cpu for which the callback should be invoked |
| 126 | * @step: The step in the state machine |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 127 | * @bringup: True if the bringup callback should be invoked |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 128 | * |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 129 | * Called from cpu hotplug and from the state register machinery. |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 130 | */ |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 131 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 132 | bool bringup, struct hlist_node *node) |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 133 | { |
| 134 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 135 | struct cpuhp_step *step = cpuhp_get_step(state); |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 136 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
| 137 | int (*cb)(unsigned int cpu); |
| 138 | int ret, cnt; |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 139 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 140 | if (!step->multi_instance) { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 141 | cb = bringup ? step->startup.single : step->teardown.single; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 142 | if (!cb) |
| 143 | return 0; |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 144 | trace_cpuhp_enter(cpu, st->target, state, cb); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 145 | ret = cb(cpu); |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 146 | trace_cpuhp_exit(cpu, st->state, state, ret); |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 147 | return ret; |
| 148 | } |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 149 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 150 | if (!cbm) |
| 151 | return 0; |
| 152 | |
| 153 | /* Single invocation for instance add/remove */ |
| 154 | if (node) { |
| 155 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| 156 | ret = cbm(cpu, node); |
| 157 | trace_cpuhp_exit(cpu, st->state, state, ret); |
| 158 | return ret; |
| 159 | } |
| 160 | |
| 161 | /* State transition. Invoke on all instances */ |
| 162 | cnt = 0; |
| 163 | hlist_for_each(node, &step->list) { |
| 164 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| 165 | ret = cbm(cpu, node); |
| 166 | trace_cpuhp_exit(cpu, st->state, state, ret); |
| 167 | if (ret) |
| 168 | goto err; |
| 169 | cnt++; |
| 170 | } |
| 171 | return 0; |
| 172 | err: |
| 173 | /* Rollback the instances if one failed */ |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 174 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 175 | if (!cbm) |
| 176 | return ret; |
| 177 | |
| 178 | hlist_for_each(node, &step->list) { |
| 179 | if (!cnt--) |
| 180 | break; |
| 181 | cbm(cpu, node); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 182 | } |
| 183 | return ret; |
| 184 | } |
| 185 | |
Rusty Russell | 98a79d6 | 2008-12-13 21:19:41 +1030 | [diff] [blame] | 186 | #ifdef CONFIG_SMP |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 187 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
Linus Torvalds | aa95387 | 2006-07-23 12:12:16 -0700 | [diff] [blame] | 188 | static DEFINE_MUTEX(cpu_add_remove_lock); |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 189 | bool cpuhp_tasks_frozen; |
| 190 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 192 | /* |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 193 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
| 194 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. |
| 195 | * The APIs cpu_notifier_register_begin/done() must be used to protect CPU |
| 196 | * hotplug callback (un)registration performed using __register_cpu_notifier() |
| 197 | * or __unregister_cpu_notifier(). |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 198 | */ |
| 199 | void cpu_maps_update_begin(void) |
| 200 | { |
| 201 | mutex_lock(&cpu_add_remove_lock); |
| 202 | } |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 203 | EXPORT_SYMBOL(cpu_notifier_register_begin); |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 204 | |
| 205 | void cpu_maps_update_done(void) |
| 206 | { |
| 207 | mutex_unlock(&cpu_add_remove_lock); |
| 208 | } |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 209 | EXPORT_SYMBOL(cpu_notifier_register_done); |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 210 | |
Daniel J Blueman | 5c113fb | 2010-06-01 12:15:11 +0100 | [diff] [blame] | 211 | static RAW_NOTIFIER_HEAD(cpu_chain); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 213 | /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
| 214 | * Should always be manipulated under cpu_add_remove_lock |
| 215 | */ |
| 216 | static int cpu_hotplug_disabled; |
| 217 | |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 218 | #ifdef CONFIG_HOTPLUG_CPU |
| 219 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 220 | static struct { |
| 221 | struct task_struct *active_writer; |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 222 | /* wait queue to wake up the active_writer */ |
| 223 | wait_queue_head_t wq; |
| 224 | /* verifies that no writer will get active while readers are active */ |
| 225 | struct mutex lock; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 226 | /* |
| 227 | * Also blocks the new readers during |
| 228 | * an ongoing cpu hotplug operation. |
| 229 | */ |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 230 | atomic_t refcount; |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 231 | |
| 232 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
| 233 | struct lockdep_map dep_map; |
| 234 | #endif |
Linus Torvalds | 31950eb | 2009-06-22 21:18:12 -0700 | [diff] [blame] | 235 | } cpu_hotplug = { |
| 236 | .active_writer = NULL, |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 237 | .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq), |
Linus Torvalds | 31950eb | 2009-06-22 21:18:12 -0700 | [diff] [blame] | 238 | .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock), |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 239 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
Joonas Lahtinen | a705e07 | 2016-10-12 13:18:56 +0300 | [diff] [blame] | 240 | .dep_map = STATIC_LOCKDEP_MAP_INIT("cpu_hotplug.dep_map", &cpu_hotplug.dep_map), |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 241 | #endif |
Linus Torvalds | 31950eb | 2009-06-22 21:18:12 -0700 | [diff] [blame] | 242 | }; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 243 | |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 244 | /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */ |
| 245 | #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] | 246 | #define cpuhp_lock_acquire_tryread() \ |
| 247 | lock_map_acquire_tryread(&cpu_hotplug.dep_map) |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 248 | #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map) |
| 249 | #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map) |
| 250 | |
Prateek Sood | e9e7b75 | 2017-09-08 13:10:55 +0530 | [diff] [blame] | 251 | void cpu_hotplug_mutex_held(void) |
| 252 | { |
| 253 | lockdep_assert_held(&cpu_hotplug.lock); |
| 254 | } |
| 255 | EXPORT_SYMBOL(cpu_hotplug_mutex_held); |
Paul E. McKenney | 62db99f | 2014-10-22 14:51:49 -0700 | [diff] [blame] | 256 | |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 257 | void get_online_cpus(void) |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 258 | { |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 259 | might_sleep(); |
| 260 | if (cpu_hotplug.active_writer == current) |
Linus Torvalds | aa95387 | 2006-07-23 12:12:16 -0700 | [diff] [blame] | 261 | return; |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 262 | cpuhp_lock_acquire_read(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 263 | mutex_lock(&cpu_hotplug.lock); |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 264 | atomic_inc(&cpu_hotplug.refcount); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 265 | mutex_unlock(&cpu_hotplug.lock); |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 266 | } |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 267 | EXPORT_SYMBOL_GPL(get_online_cpus); |
Ashok Raj | 90d45d1 | 2005-11-08 21:34:24 -0800 | [diff] [blame] | 268 | |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 269 | void put_online_cpus(void) |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 270 | { |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 271 | int refcount; |
| 272 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 273 | if (cpu_hotplug.active_writer == current) |
Linus Torvalds | aa95387 | 2006-07-23 12:12:16 -0700 | [diff] [blame] | 274 | return; |
Srivatsa S. Bhat | 075663d | 2012-10-08 16:28:20 -0700 | [diff] [blame] | 275 | |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 276 | refcount = atomic_dec_return(&cpu_hotplug.refcount); |
| 277 | if (WARN_ON(refcount < 0)) /* try to fix things up */ |
| 278 | atomic_inc(&cpu_hotplug.refcount); |
Srivatsa S. Bhat | 075663d | 2012-10-08 16:28:20 -0700 | [diff] [blame] | 279 | |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 280 | if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq)) |
| 281 | wake_up(&cpu_hotplug.wq); |
| 282 | |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 283 | cpuhp_lock_release(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 284 | |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 285 | } |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 286 | EXPORT_SYMBOL_GPL(put_online_cpus); |
Ashok Raj | a9d9baa | 2005-11-28 13:43:46 -0800 | [diff] [blame] | 287 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 288 | /* |
| 289 | * This ensures that the hotplug operation can begin only when the |
| 290 | * refcount goes to zero. |
| 291 | * |
| 292 | * Note that during a cpu-hotplug operation, the new readers, if any, |
| 293 | * will be blocked by the cpu_hotplug.lock |
| 294 | * |
Oleg Nesterov | d2ba7e2 | 2008-04-29 01:00:29 -0700 | [diff] [blame] | 295 | * Since cpu_hotplug_begin() is always called after invoking |
| 296 | * 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] | 297 | * |
| 298 | * Note that theoretically, there is a possibility of a livelock: |
| 299 | * - Refcount goes to zero, last reader wakes up the sleeping |
| 300 | * writer. |
| 301 | * - Last reader unlocks the cpu_hotplug.lock. |
| 302 | * - A new reader arrives at this moment, bumps up the refcount. |
| 303 | * - The writer acquires the cpu_hotplug.lock finds the refcount |
| 304 | * non zero and goes to sleep again. |
| 305 | * |
| 306 | * However, this is very difficult to achieve in practice since |
Gautham R Shenoy | 86ef5c9 | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 307 | * 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] | 308 | * |
| 309 | */ |
Toshi Kani | b9d10be | 2013-08-12 09:45:53 -0600 | [diff] [blame] | 310 | void cpu_hotplug_begin(void) |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 311 | { |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 312 | DEFINE_WAIT(wait); |
Oleg Nesterov | d2ba7e2 | 2008-04-29 01:00:29 -0700 | [diff] [blame] | 313 | |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 314 | cpu_hotplug.active_writer = current; |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 315 | cpuhp_lock_acquire(); |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 316 | |
Oleg Nesterov | d2ba7e2 | 2008-04-29 01:00:29 -0700 | [diff] [blame] | 317 | for (;;) { |
| 318 | mutex_lock(&cpu_hotplug.lock); |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 319 | prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE); |
| 320 | if (likely(!atomic_read(&cpu_hotplug.refcount))) |
| 321 | break; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 322 | mutex_unlock(&cpu_hotplug.lock); |
| 323 | schedule(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 324 | } |
David Hildenbrand | 87af9e7 | 2014-12-12 10:11:44 +0100 | [diff] [blame] | 325 | finish_wait(&cpu_hotplug.wq, &wait); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 326 | } |
| 327 | |
Toshi Kani | b9d10be | 2013-08-12 09:45:53 -0600 | [diff] [blame] | 328 | void cpu_hotplug_done(void) |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 329 | { |
| 330 | cpu_hotplug.active_writer = NULL; |
| 331 | mutex_unlock(&cpu_hotplug.lock); |
Gautham R. Shenoy | a19423b | 2014-03-11 02:04:03 +0530 | [diff] [blame] | 332 | cpuhp_lock_release(); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 333 | } |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 334 | |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 335 | /* |
| 336 | * Wait for currently running CPU hotplug operations to complete (if any) and |
| 337 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects |
| 338 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the |
| 339 | * hotplug path before performing hotplug operations. So acquiring that lock |
| 340 | * guarantees mutual exclusion from any currently running hotplug operations. |
| 341 | */ |
| 342 | void cpu_hotplug_disable(void) |
| 343 | { |
| 344 | cpu_maps_update_begin(); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 345 | cpu_hotplug_disabled++; |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 346 | cpu_maps_update_done(); |
| 347 | } |
Vitaly Kuznetsov | 32145c4 | 2015-08-05 00:52:47 -0700 | [diff] [blame] | 348 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 349 | |
Lianwei Wang | 01b4115 | 2016-06-09 23:43:28 -0700 | [diff] [blame] | 350 | static void __cpu_hotplug_enable(void) |
| 351 | { |
| 352 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) |
| 353 | return; |
| 354 | cpu_hotplug_disabled--; |
| 355 | } |
| 356 | |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 357 | void cpu_hotplug_enable(void) |
| 358 | { |
| 359 | cpu_maps_update_begin(); |
Lianwei Wang | 01b4115 | 2016-06-09 23:43:28 -0700 | [diff] [blame] | 360 | __cpu_hotplug_enable(); |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 361 | cpu_maps_update_done(); |
| 362 | } |
Vitaly Kuznetsov | 32145c4 | 2015-08-05 00:52:47 -0700 | [diff] [blame] | 363 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
Toshi Kani | b9d10be | 2013-08-12 09:45:53 -0600 | [diff] [blame] | 364 | #endif /* CONFIG_HOTPLUG_CPU */ |
Lai Jiangshan | 79a6cde | 2010-05-26 14:43:36 -0700 | [diff] [blame] | 365 | |
Thomas Gleixner | a3c901b | 2018-11-25 19:33:39 +0100 | [diff] [blame] | 366 | /* |
| 367 | * Architectures that need SMT-specific errata handling during SMT hotplug |
| 368 | * should override this. |
| 369 | */ |
| 370 | void __weak arch_smt_update(void) { } |
| 371 | |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 372 | #ifdef CONFIG_HOTPLUG_SMT |
| 373 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; |
Konrad Rzeszutek Wilk | a0695af | 2018-06-20 11:29:53 -0400 | [diff] [blame] | 374 | EXPORT_SYMBOL_GPL(cpu_smt_control); |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 375 | |
Thomas Gleixner | c504b9f | 2018-08-07 08:19:57 +0200 | [diff] [blame] | 376 | static bool cpu_smt_available __read_mostly; |
| 377 | |
Jiri Kosina | a69c5e0 | 2018-07-13 16:23:23 +0200 | [diff] [blame] | 378 | void __init cpu_smt_disable(bool force) |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 379 | { |
Jiri Kosina | a69c5e0 | 2018-07-13 16:23:23 +0200 | [diff] [blame] | 380 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || |
| 381 | cpu_smt_control == CPU_SMT_NOT_SUPPORTED) |
| 382 | return; |
| 383 | |
| 384 | if (force) { |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 385 | pr_info("SMT: Force disabled\n"); |
| 386 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; |
Jiri Kosina | a69c5e0 | 2018-07-13 16:23:23 +0200 | [diff] [blame] | 387 | } else { |
Borislav Petkov | 6270cc3 | 2018-10-04 19:22:27 +0200 | [diff] [blame] | 388 | pr_info("SMT: disabled\n"); |
Jiri Kosina | a69c5e0 | 2018-07-13 16:23:23 +0200 | [diff] [blame] | 389 | cpu_smt_control = CPU_SMT_DISABLED; |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 390 | } |
Jiri Kosina | a69c5e0 | 2018-07-13 16:23:23 +0200 | [diff] [blame] | 391 | } |
| 392 | |
Thomas Gleixner | 929d3b2 | 2018-07-13 16:23:24 +0200 | [diff] [blame] | 393 | /* |
| 394 | * The decision whether SMT is supported can only be done after the full |
Thomas Gleixner | c504b9f | 2018-08-07 08:19:57 +0200 | [diff] [blame] | 395 | * CPU identification. Called from architecture code before non boot CPUs |
| 396 | * are brought up. |
| 397 | */ |
| 398 | void __init cpu_smt_check_topology_early(void) |
| 399 | { |
| 400 | if (!topology_smt_supported()) |
| 401 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
| 402 | } |
| 403 | |
| 404 | /* |
| 405 | * If SMT was disabled by BIOS, detect it here, after the CPUs have been |
| 406 | * brought online. This ensures the smt/l1tf sysfs entries are consistent |
| 407 | * with reality. cpu_smt_available is set to true during the bringup of non |
| 408 | * boot CPUs when a SMT sibling is detected. Note, this may overwrite |
| 409 | * cpu_smt_control's previous setting. |
Thomas Gleixner | 929d3b2 | 2018-07-13 16:23:24 +0200 | [diff] [blame] | 410 | */ |
| 411 | void __init cpu_smt_check_topology(void) |
| 412 | { |
Thomas Gleixner | c504b9f | 2018-08-07 08:19:57 +0200 | [diff] [blame] | 413 | if (!cpu_smt_available) |
Thomas Gleixner | 929d3b2 | 2018-07-13 16:23:24 +0200 | [diff] [blame] | 414 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
| 415 | } |
| 416 | |
Jiri Kosina | a69c5e0 | 2018-07-13 16:23:23 +0200 | [diff] [blame] | 417 | static int __init smt_cmdline_disable(char *str) |
| 418 | { |
| 419 | cpu_smt_disable(str && !strcmp(str, "force")); |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 420 | return 0; |
| 421 | } |
| 422 | early_param("nosmt", smt_cmdline_disable); |
| 423 | |
| 424 | static inline bool cpu_smt_allowed(unsigned int cpu) |
| 425 | { |
Thomas Gleixner | c504b9f | 2018-08-07 08:19:57 +0200 | [diff] [blame] | 426 | if (topology_is_primary_thread(cpu)) |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 427 | return true; |
| 428 | |
Thomas Gleixner | c504b9f | 2018-08-07 08:19:57 +0200 | [diff] [blame] | 429 | /* |
| 430 | * If the CPU is not a 'primary' thread and the booted_once bit is |
| 431 | * set then the processor has SMT support. Store this information |
| 432 | * for the late check of SMT support in cpu_smt_check_topology(). |
| 433 | */ |
| 434 | if (per_cpu(cpuhp_state, cpu).booted_once) |
| 435 | cpu_smt_available = true; |
| 436 | |
| 437 | if (cpu_smt_control == CPU_SMT_ENABLED) |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 438 | return true; |
| 439 | |
| 440 | /* |
| 441 | * On x86 it's required to boot all logical CPUs at least once so |
| 442 | * that the init code can get a chance to set CR4.MCE on each |
| 443 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any |
| 444 | * core will shutdown the machine. |
| 445 | */ |
| 446 | return !per_cpu(cpuhp_state, cpu).booted_once; |
| 447 | } |
| 448 | #else |
| 449 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } |
| 450 | #endif |
| 451 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 452 | /* Need to know about CPUs going up/down? */ |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 453 | int register_cpu_notifier(struct notifier_block *nb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | { |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 455 | int ret; |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 456 | cpu_maps_update_begin(); |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 457 | ret = raw_notifier_chain_register(&cpu_chain, nb); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 458 | cpu_maps_update_done(); |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 459 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | } |
Chandra Seetharaman | 65edc68 | 2006-06-27 02:54:08 -0700 | [diff] [blame] | 461 | |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 462 | int __register_cpu_notifier(struct notifier_block *nb) |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 463 | { |
| 464 | return raw_notifier_chain_register(&cpu_chain, nb); |
| 465 | } |
| 466 | |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 467 | 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] | 468 | int *nr_calls) |
| 469 | { |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 470 | unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0; |
| 471 | void *hcpu = (void *)(long)cpu; |
| 472 | |
Akinobu Mita | e6bde73 | 2010-05-26 14:43:29 -0700 | [diff] [blame] | 473 | int ret; |
| 474 | |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 475 | 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] | 476 | nr_calls); |
Akinobu Mita | e6bde73 | 2010-05-26 14:43:29 -0700 | [diff] [blame] | 477 | |
| 478 | return notifier_to_errno(ret); |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 479 | } |
| 480 | |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 481 | static int cpu_notify(unsigned long val, unsigned int cpu) |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 482 | { |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 483 | return __cpu_notify(val, cpu, -1, NULL); |
Akinobu Mita | e9fb763 | 2010-05-26 14:43:28 -0700 | [diff] [blame] | 484 | } |
| 485 | |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 486 | static void cpu_notify_nofail(unsigned long val, unsigned int cpu) |
| 487 | { |
| 488 | BUG_ON(cpu_notify(val, cpu)); |
| 489 | } |
| 490 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 491 | /* Notifier wrappers for transitioning to state machine */ |
| 492 | static int notify_prepare(unsigned int cpu) |
| 493 | { |
| 494 | int nr_calls = 0; |
| 495 | int ret; |
| 496 | |
| 497 | ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls); |
| 498 | if (ret) { |
| 499 | nr_calls--; |
| 500 | printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", |
| 501 | __func__, cpu); |
| 502 | __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL); |
| 503 | } |
| 504 | return ret; |
| 505 | } |
| 506 | |
| 507 | static int notify_online(unsigned int cpu) |
| 508 | { |
| 509 | cpu_notify(CPU_ONLINE, cpu); |
| 510 | return 0; |
| 511 | } |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 512 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st); |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 513 | |
Thomas Gleixner | 7b4e4b1 | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 514 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st); |
| 515 | |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 516 | static int bringup_wait_for_ap(unsigned int cpu) |
| 517 | { |
| 518 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 519 | |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 520 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 521 | wait_for_completion(&st->done); |
Thomas Gleixner | 6b3d13f | 2017-07-11 22:06:24 +0200 | [diff] [blame] | 522 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
| 523 | return -ECANCELED; |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 524 | |
| 525 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ |
| 526 | stop_machine_unpark(cpu); |
| 527 | kthread_unpark(st->thread); |
| 528 | |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 529 | /* |
| 530 | * SMT soft disabling on X86 requires to bring the CPU out of the |
| 531 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The |
| 532 | * CPU marked itself as booted_once in cpu_notify_starting() so the |
| 533 | * cpu_smt_allowed() check will now return false if this is not the |
| 534 | * primary sibling. |
| 535 | */ |
| 536 | if (!cpu_smt_allowed(cpu)) |
| 537 | return -ECANCELED; |
| 538 | |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 539 | /* Should we go further up ? */ |
| 540 | if (st->target > CPUHP_AP_ONLINE_IDLE) { |
| 541 | __cpuhp_kick_ap_work(st); |
| 542 | wait_for_completion(&st->done); |
| 543 | } |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 544 | return st->result; |
| 545 | } |
| 546 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 547 | static int bringup_cpu(unsigned int cpu) |
| 548 | { |
| 549 | struct task_struct *idle = idle_thread_get(cpu); |
| 550 | int ret; |
| 551 | |
Boris Ostrovsky | aa87717 | 2016-08-03 13:22:28 -0400 | [diff] [blame] | 552 | /* |
| 553 | * Some architectures have to walk the irq descriptors to |
| 554 | * setup the vector space for the cpu which comes online. |
| 555 | * Prevent irq alloc/free across the bringup. |
| 556 | */ |
| 557 | irq_lock_sparse(); |
| 558 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 559 | /* Arch-specific enabling code. */ |
| 560 | ret = __cpu_up(cpu, idle); |
Boris Ostrovsky | aa87717 | 2016-08-03 13:22:28 -0400 | [diff] [blame] | 561 | irq_unlock_sparse(); |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 562 | if (ret) { |
| 563 | cpu_notify(CPU_UP_CANCELED, cpu); |
| 564 | return ret; |
| 565 | } |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 566 | return bringup_wait_for_ap(cpu); |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 567 | } |
| 568 | |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 569 | /* |
| 570 | * Hotplug state machine related functions |
| 571 | */ |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 572 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 573 | { |
| 574 | for (st->state++; st->state < st->target; st->state++) { |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 575 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 576 | |
| 577 | if (!step->skip_onerr) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 578 | cpuhp_invoke_callback(cpu, st->state, true, NULL); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 579 | } |
| 580 | } |
| 581 | |
| 582 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 583 | enum cpuhp_state target) |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 584 | { |
| 585 | enum cpuhp_state prev_state = st->state; |
| 586 | int ret = 0; |
| 587 | |
| 588 | for (; st->state > target; st->state--) { |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 589 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL); |
Channagoud Kadabi | bd019ce | 2017-06-19 17:14:52 -0700 | [diff] [blame] | 590 | BUG_ON(ret && st->state < CPUHP_AP_IDLE_DEAD); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 591 | if (ret) { |
| 592 | st->target = prev_state; |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 593 | undo_cpu_down(cpu, st); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 594 | break; |
| 595 | } |
| 596 | } |
| 597 | return ret; |
| 598 | } |
| 599 | |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 600 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 601 | { |
| 602 | for (st->state--; st->state > st->target; st->state--) { |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 603 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 604 | |
| 605 | if (!step->skip_onerr) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 606 | cpuhp_invoke_callback(cpu, st->state, false, NULL); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 607 | } |
| 608 | } |
| 609 | |
Thomas Gleixner | ce4fbb9 | 2019-03-26 17:36:05 +0100 | [diff] [blame] | 610 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
| 611 | { |
| 612 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) |
| 613 | return true; |
| 614 | /* |
| 615 | * When CPU hotplug is disabled, then taking the CPU down is not |
| 616 | * possible because takedown_cpu() and the architecture and |
| 617 | * subsystem specific mechanisms are not available. So the CPU |
| 618 | * which would be completely unplugged again needs to stay around |
| 619 | * in the current state. |
| 620 | */ |
| 621 | return st->state <= CPUHP_BRINGUP_CPU; |
| 622 | } |
| 623 | |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 624 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 625 | enum cpuhp_state target) |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 626 | { |
| 627 | enum cpuhp_state prev_state = st->state; |
| 628 | int ret = 0; |
| 629 | |
| 630 | while (st->state < target) { |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 631 | st->state++; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 632 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL); |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 633 | if (ret) { |
Thomas Gleixner | ce4fbb9 | 2019-03-26 17:36:05 +0100 | [diff] [blame] | 634 | if (can_rollback_cpu(st)) { |
| 635 | st->target = prev_state; |
| 636 | undo_cpu_up(cpu, st); |
| 637 | } |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 638 | break; |
| 639 | } |
| 640 | } |
| 641 | return ret; |
| 642 | } |
| 643 | |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 644 | /* |
| 645 | * The cpu hotplug threads manage the bringup and teardown of the cpus |
| 646 | */ |
| 647 | static void cpuhp_create(unsigned int cpu) |
| 648 | { |
| 649 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 650 | |
| 651 | init_completion(&st->done); |
| 652 | } |
| 653 | |
| 654 | static int cpuhp_should_run(unsigned int cpu) |
| 655 | { |
| 656 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 657 | |
| 658 | return st->should_run; |
| 659 | } |
| 660 | |
| 661 | /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */ |
| 662 | static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 663 | { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 664 | enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 665 | |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 666 | return cpuhp_down_callbacks(cpu, st, target); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 667 | } |
| 668 | |
| 669 | /* Execute the online startup callbacks. Used to be CPU_ONLINE */ |
| 670 | static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st) |
| 671 | { |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 672 | return cpuhp_up_callbacks(cpu, st, st->target); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 673 | } |
| 674 | |
| 675 | /* |
| 676 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke |
| 677 | * callbacks when a state gets [un]installed at runtime. |
| 678 | */ |
| 679 | static void cpuhp_thread_fun(unsigned int cpu) |
| 680 | { |
| 681 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 682 | int ret = 0; |
| 683 | |
| 684 | /* |
| 685 | * Paired with the mb() in cpuhp_kick_ap_work and |
| 686 | * cpuhp_invoke_ap_callback, so the work set is consistent visible. |
| 687 | */ |
| 688 | smp_mb(); |
| 689 | if (!st->should_run) |
| 690 | return; |
| 691 | |
| 692 | st->should_run = false; |
| 693 | |
Thomas Gleixner | c198e22 | 2017-05-24 10:15:43 +0200 | [diff] [blame] | 694 | lock_map_acquire(&cpuhp_state_lock_map); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 695 | /* Single callback invocation for [un]install ? */ |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 696 | if (st->single) { |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 697 | if (st->cb_state < CPUHP_AP_ONLINE) { |
| 698 | local_irq_disable(); |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 699 | ret = cpuhp_invoke_callback(cpu, st->cb_state, |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 700 | st->bringup, st->node); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 701 | local_irq_enable(); |
| 702 | } else { |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 703 | ret = cpuhp_invoke_callback(cpu, st->cb_state, |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 704 | st->bringup, st->node); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 705 | } |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 706 | } else if (st->rollback) { |
| 707 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); |
| 708 | |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 709 | undo_cpu_down(cpu, st); |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 710 | /* |
| 711 | * This is a momentary workaround to keep the notifier users |
| 712 | * happy. Will go away once we got rid of the notifiers. |
| 713 | */ |
| 714 | cpu_notify_nofail(CPU_DOWN_FAILED, cpu); |
| 715 | st->rollback = false; |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 716 | } else { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 717 | /* Cannot happen .... */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 718 | BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 719 | |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 720 | /* Regular hotplug work */ |
| 721 | if (st->state < st->target) |
| 722 | ret = cpuhp_ap_online(cpu, st); |
| 723 | else if (st->state > st->target) |
| 724 | ret = cpuhp_ap_offline(cpu, st); |
| 725 | } |
Thomas Gleixner | c198e22 | 2017-05-24 10:15:43 +0200 | [diff] [blame] | 726 | lock_map_release(&cpuhp_state_lock_map); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 727 | st->result = ret; |
| 728 | complete(&st->done); |
| 729 | } |
| 730 | |
| 731 | /* Invoke a single callback on a remote cpu */ |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 732 | static int |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 733 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
| 734 | struct hlist_node *node) |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 735 | { |
| 736 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 737 | |
| 738 | if (!cpu_online(cpu)) |
| 739 | return 0; |
| 740 | |
Thomas Gleixner | c198e22 | 2017-05-24 10:15:43 +0200 | [diff] [blame] | 741 | lock_map_acquire(&cpuhp_state_lock_map); |
| 742 | lock_map_release(&cpuhp_state_lock_map); |
| 743 | |
Thomas Gleixner | 6a4e245 | 2016-07-13 17:16:03 +0000 | [diff] [blame] | 744 | /* |
| 745 | * If we are up and running, use the hotplug thread. For early calls |
| 746 | * we invoke the thread function directly. |
| 747 | */ |
| 748 | if (!st->thread) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 749 | return cpuhp_invoke_callback(cpu, state, bringup, node); |
Thomas Gleixner | 6a4e245 | 2016-07-13 17:16:03 +0000 | [diff] [blame] | 750 | |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 751 | st->cb_state = state; |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 752 | st->single = true; |
| 753 | st->bringup = bringup; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 754 | st->node = node; |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 755 | |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 756 | /* |
| 757 | * Make sure the above stores are visible before should_run becomes |
| 758 | * true. Paired with the mb() above in cpuhp_thread_fun() |
| 759 | */ |
| 760 | smp_mb(); |
| 761 | st->should_run = true; |
| 762 | wake_up_process(st->thread); |
| 763 | wait_for_completion(&st->done); |
| 764 | return st->result; |
| 765 | } |
| 766 | |
| 767 | /* Regular hotplug invocation of the AP hotplug thread */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 768 | static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st) |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 769 | { |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 770 | st->result = 0; |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 771 | st->single = false; |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 772 | /* |
| 773 | * Make sure the above stores are visible before should_run becomes |
| 774 | * true. Paired with the mb() above in cpuhp_thread_fun() |
| 775 | */ |
| 776 | smp_mb(); |
| 777 | st->should_run = true; |
| 778 | wake_up_process(st->thread); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 779 | } |
| 780 | |
| 781 | static int cpuhp_kick_ap_work(unsigned int cpu) |
| 782 | { |
| 783 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 784 | enum cpuhp_state state = st->state; |
| 785 | |
| 786 | trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work); |
Thomas Gleixner | c198e22 | 2017-05-24 10:15:43 +0200 | [diff] [blame] | 787 | lock_map_acquire(&cpuhp_state_lock_map); |
| 788 | lock_map_release(&cpuhp_state_lock_map); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 789 | __cpuhp_kick_ap_work(st); |
Thomas Gleixner | 4cb28ce | 2016-02-26 18:43:38 +0000 | [diff] [blame] | 790 | wait_for_completion(&st->done); |
| 791 | trace_cpuhp_exit(cpu, st->state, state, st->result); |
| 792 | return st->result; |
| 793 | } |
| 794 | |
| 795 | static struct smp_hotplug_thread cpuhp_threads = { |
| 796 | .store = &cpuhp_state.thread, |
| 797 | .create = &cpuhp_create, |
| 798 | .thread_should_run = cpuhp_should_run, |
| 799 | .thread_fn = cpuhp_thread_fun, |
| 800 | .thread_comm = "cpuhp/%u", |
| 801 | .selfparking = true, |
| 802 | }; |
| 803 | |
| 804 | void __init cpuhp_threads_init(void) |
| 805 | { |
| 806 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); |
| 807 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); |
| 808 | } |
| 809 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 810 | EXPORT_SYMBOL(register_cpu_notifier); |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 811 | EXPORT_SYMBOL(__register_cpu_notifier); |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 812 | void unregister_cpu_notifier(struct notifier_block *nb) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | { |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 814 | cpu_maps_update_begin(); |
Neil Brown | bd5349c | 2006-10-17 00:10:35 -0700 | [diff] [blame] | 815 | raw_notifier_chain_unregister(&cpu_chain, nb); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 816 | cpu_maps_update_done(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 817 | } |
| 818 | EXPORT_SYMBOL(unregister_cpu_notifier); |
| 819 | |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 820 | void __unregister_cpu_notifier(struct notifier_block *nb) |
Srivatsa S. Bhat | 93ae4f9 | 2014-03-11 02:04:14 +0530 | [diff] [blame] | 821 | { |
| 822 | raw_notifier_chain_unregister(&cpu_chain, nb); |
| 823 | } |
| 824 | EXPORT_SYMBOL(__unregister_cpu_notifier); |
| 825 | |
Michal Hocko | 56eaecc | 2016-12-07 14:54:38 +0100 | [diff] [blame] | 826 | #ifdef CONFIG_HOTPLUG_CPU |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 827 | /** |
| 828 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU |
| 829 | * @cpu: a CPU id |
| 830 | * |
| 831 | * This function walks all processes, finds a valid mm struct for each one and |
| 832 | * then clears a corresponding bit in mm's cpumask. While this all sounds |
| 833 | * trivial, there are various non-obvious corner cases, which this function |
| 834 | * tries to solve in a safe manner. |
| 835 | * |
| 836 | * Also note that the function uses a somewhat relaxed locking scheme, so it may |
| 837 | * be called only for an already offlined CPU. |
| 838 | */ |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 839 | void clear_tasks_mm_cpumask(int cpu) |
| 840 | { |
| 841 | struct task_struct *p; |
| 842 | |
| 843 | /* |
| 844 | * This function is called after the cpu is taken down and marked |
| 845 | * offline, so its not like new tasks will ever get this cpu set in |
| 846 | * their mm mask. -- Peter Zijlstra |
| 847 | * Thus, we may use rcu_read_lock() here, instead of grabbing |
| 848 | * full-fledged tasklist_lock. |
| 849 | */ |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 850 | WARN_ON(cpu_online(cpu)); |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 851 | rcu_read_lock(); |
| 852 | for_each_process(p) { |
| 853 | struct task_struct *t; |
| 854 | |
Anton Vorontsov | e4cc2f8 | 2012-05-31 16:26:26 -0700 | [diff] [blame] | 855 | /* |
| 856 | * Main thread might exit, but other threads may still have |
| 857 | * a valid mm. Find one. |
| 858 | */ |
Anton Vorontsov | cb79295 | 2012-05-31 16:26:22 -0700 | [diff] [blame] | 859 | t = find_lock_task_mm(p); |
| 860 | if (!t) |
| 861 | continue; |
| 862 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); |
| 863 | task_unlock(t); |
| 864 | } |
| 865 | rcu_read_unlock(); |
| 866 | } |
| 867 | |
Kirill Tkhai | b728ca0 | 2014-06-25 12:19:55 +0400 | [diff] [blame] | 868 | static inline void check_for_tasks(int dead_cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 869 | { |
Kirill Tkhai | b728ca0 | 2014-06-25 12:19:55 +0400 | [diff] [blame] | 870 | struct task_struct *g, *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 871 | |
Oleg Nesterov | a75a606 | 2015-09-10 15:07:50 +0200 | [diff] [blame] | 872 | read_lock(&tasklist_lock); |
| 873 | for_each_process_thread(g, p) { |
Kirill Tkhai | b728ca0 | 2014-06-25 12:19:55 +0400 | [diff] [blame] | 874 | if (!p->on_rq) |
| 875 | continue; |
| 876 | /* |
| 877 | * We do the check with unlocked task_rq(p)->lock. |
| 878 | * Order the reading to do not warn about a task, |
| 879 | * which was running on this cpu in the past, and |
| 880 | * it's just been woken on another cpu. |
| 881 | */ |
| 882 | rmb(); |
| 883 | if (task_cpu(p) != dead_cpu) |
| 884 | continue; |
| 885 | |
| 886 | pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n", |
| 887 | p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags); |
Oleg Nesterov | a75a606 | 2015-09-10 15:07:50 +0200 | [diff] [blame] | 888 | } |
| 889 | read_unlock(&tasklist_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 890 | } |
| 891 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 892 | static int notify_down_prepare(unsigned int cpu) |
| 893 | { |
| 894 | int err, nr_calls = 0; |
| 895 | |
| 896 | err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls); |
| 897 | if (err) { |
| 898 | nr_calls--; |
| 899 | __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL); |
| 900 | pr_warn("%s: attempt to take down CPU %u failed\n", |
| 901 | __func__, cpu); |
| 902 | } |
| 903 | return err; |
| 904 | } |
| 905 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 906 | /* Take this CPU down. */ |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 907 | static int take_cpu_down(void *_param) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | { |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 909 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 910 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 911 | int err, cpu = smp_processor_id(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 912 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 913 | /* Ensure this CPU doesn't handle any more interrupts. */ |
| 914 | err = __cpu_disable(); |
| 915 | if (err < 0) |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 916 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 917 | |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 918 | /* |
| 919 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not |
| 920 | * do this step again. |
| 921 | */ |
| 922 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); |
| 923 | st->state--; |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 924 | /* Invoke the former CPU_DYING callbacks */ |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 925 | for (; st->state > target; st->state--) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 926 | cpuhp_invoke_callback(cpu, st->state, false, NULL); |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 927 | |
Thomas Gleixner | 52c063d | 2015-04-03 02:37:24 +0200 | [diff] [blame] | 928 | /* Give up timekeeping duties */ |
| 929 | tick_handover_do_timer(); |
Thomas Gleixner | 14e568e | 2013-01-31 12:11:14 +0000 | [diff] [blame] | 930 | /* Park the stopper thread */ |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 931 | stop_machine_park(cpu); |
Zwane Mwaikambo | f370513 | 2005-06-25 14:54:50 -0700 | [diff] [blame] | 932 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | } |
| 934 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 935 | static int takedown_cpu(unsigned int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | { |
Thomas Gleixner | e69aab1 | 2016-02-26 18:43:43 +0000 | [diff] [blame] | 937 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 938 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 939 | |
Thomas Gleixner | 2a58c52 | 2016-03-10 20:42:08 +0100 | [diff] [blame] | 940 | /* Park the smpboot threads */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 941 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
| 942 | |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 943 | /* |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 944 | * Prevent irq alloc/free while the dying cpu reorganizes the |
| 945 | * interrupt affinities. |
| 946 | */ |
| 947 | irq_lock_sparse(); |
| 948 | |
| 949 | /* |
Peter Zijlstra | 6acce3e | 2013-10-11 14:38:20 +0200 | [diff] [blame] | 950 | * So now all preempt/rcu users must observe !cpu_active(). |
| 951 | */ |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 952 | err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); |
Rusty Russell | 0432158 | 2008-07-28 12:16:29 -0500 | [diff] [blame] | 953 | if (err) { |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 954 | /* CPU refused to die */ |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 955 | irq_unlock_sparse(); |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 956 | /* Unpark the hotplug thread so we can rollback there */ |
| 957 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 958 | return err; |
Satoru Takeuchi | 8fa1d7d | 2006-10-28 10:38:57 -0700 | [diff] [blame] | 959 | } |
Rusty Russell | 0432158 | 2008-07-28 12:16:29 -0500 | [diff] [blame] | 960 | BUG_ON(cpu_online(cpu)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | |
Peter Zijlstra | 48c5cca | 2010-11-13 19:32:29 +0100 | [diff] [blame] | 962 | /* |
Thomas Gleixner | ee1e714 | 2016-08-18 14:57:16 +0200 | [diff] [blame] | 963 | * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all |
Peter Zijlstra | 48c5cca | 2010-11-13 19:32:29 +0100 | [diff] [blame] | 964 | * runnable tasks from the cpu, there's only the idle task left now |
| 965 | * that the migration thread is done doing the stop_machine thing. |
Peter Zijlstra | 51a96c7 | 2010-11-19 20:37:53 +0100 | [diff] [blame] | 966 | * |
| 967 | * Wait for the stop thread to go away. |
Peter Zijlstra | 48c5cca | 2010-11-13 19:32:29 +0100 | [diff] [blame] | 968 | */ |
Thomas Gleixner | e69aab1 | 2016-02-26 18:43:43 +0000 | [diff] [blame] | 969 | wait_for_completion(&st->done); |
| 970 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 971 | |
Thomas Gleixner | a899418 | 2015-07-05 17:12:30 +0000 | [diff] [blame] | 972 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
| 973 | irq_unlock_sparse(); |
| 974 | |
Preeti U Murthy | 345527b | 2015-03-30 14:59:19 +0530 | [diff] [blame] | 975 | hotplug_cpu__broadcast_tick_pull(cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 976 | /* This actually kills the CPU. */ |
| 977 | __cpu_die(cpu); |
| 978 | |
Thomas Gleixner | a49b116 | 2015-04-03 02:38:05 +0200 | [diff] [blame] | 979 | tick_cleanup_dead_cpu(cpu); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 980 | return 0; |
| 981 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 982 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 983 | static int notify_dead(unsigned int cpu) |
| 984 | { |
| 985 | cpu_notify_nofail(CPU_DEAD, cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 986 | check_for_tasks(cpu); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 987 | return 0; |
| 988 | } |
| 989 | |
Thomas Gleixner | 71f87b2 | 2016-03-03 10:52:10 +0100 | [diff] [blame] | 990 | static void cpuhp_complete_idle_dead(void *arg) |
| 991 | { |
| 992 | struct cpuhp_cpu_state *st = arg; |
| 993 | |
| 994 | complete(&st->done); |
| 995 | } |
| 996 | |
Thomas Gleixner | e69aab1 | 2016-02-26 18:43:43 +0000 | [diff] [blame] | 997 | void cpuhp_report_idle_dead(void) |
| 998 | { |
| 999 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| 1000 | |
| 1001 | BUG_ON(st->state != CPUHP_AP_OFFLINE); |
Thomas Gleixner | 27d50c7 | 2016-02-26 18:43:44 +0000 | [diff] [blame] | 1002 | rcu_report_dead(smp_processor_id()); |
Thomas Gleixner | 71f87b2 | 2016-03-03 10:52:10 +0100 | [diff] [blame] | 1003 | st->state = CPUHP_AP_IDLE_DEAD; |
| 1004 | /* |
| 1005 | * We cannot call complete after rcu_report_dead() so we delegate it |
| 1006 | * to an online cpu. |
| 1007 | */ |
| 1008 | smp_call_function_single(cpumask_first(cpu_online_mask), |
| 1009 | cpuhp_complete_idle_dead, st, 0); |
Thomas Gleixner | e69aab1 | 2016-02-26 18:43:43 +0000 | [diff] [blame] | 1010 | } |
| 1011 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1012 | #else |
| 1013 | #define notify_down_prepare NULL |
| 1014 | #define takedown_cpu NULL |
| 1015 | #define notify_dead NULL |
| 1016 | #endif |
| 1017 | |
| 1018 | #ifdef CONFIG_HOTPLUG_CPU |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1019 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1020 | /* Requires cpu_add_remove_lock to be held */ |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1021 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
| 1022 | enum cpuhp_state target) |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1023 | { |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1024 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1025 | int prev_state, ret = 0; |
| 1026 | bool hasdied = false; |
Prasad Sodagudi | 0a29343 | 2017-10-13 15:28:58 -0700 | [diff] [blame] | 1027 | u64 start_time = 0; |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1028 | |
| 1029 | if (num_online_cpus() == 1) |
| 1030 | return -EBUSY; |
| 1031 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1032 | if (!cpu_present(cpu)) |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1033 | return -EINVAL; |
| 1034 | |
Pavankumar Kondeti | 68435b0 | 2017-06-29 16:17:55 +0530 | [diff] [blame] | 1035 | if (!tasks_frozen && !cpu_isolated(cpu) && num_online_uniso_cpus() == 1) |
| 1036 | return -EBUSY; |
| 1037 | |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1038 | cpu_hotplug_begin(); |
Prasad Sodagudi | 0a29343 | 2017-10-13 15:28:58 -0700 | [diff] [blame] | 1039 | if (trace_cpuhp_latency_enabled()) |
| 1040 | start_time = sched_clock(); |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1041 | |
| 1042 | cpuhp_tasks_frozen = tasks_frozen; |
| 1043 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1044 | prev_state = st->state; |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1045 | st->target = target; |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1046 | /* |
| 1047 | * If the current CPU state is in the range of the AP hotplug thread, |
| 1048 | * then we need to kick the thread. |
| 1049 | */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1050 | if (st->state > CPUHP_TEARDOWN_CPU) { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1051 | ret = cpuhp_kick_ap_work(cpu); |
| 1052 | /* |
| 1053 | * The AP side has done the error rollback already. Just |
| 1054 | * return the error code.. |
| 1055 | */ |
| 1056 | if (ret) |
| 1057 | goto out; |
| 1058 | |
| 1059 | /* |
| 1060 | * We might have stopped still in the range of the AP hotplug |
| 1061 | * thread. Nothing to do anymore. |
| 1062 | */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1063 | if (st->state > CPUHP_TEARDOWN_CPU) |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1064 | goto out; |
| 1065 | } |
| 1066 | /* |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1067 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1068 | * to do the further cleanups. |
| 1069 | */ |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 1070 | ret = cpuhp_down_callbacks(cpu, st, target); |
Sebastian Andrzej Siewior | 3b9d6da | 2016-04-08 14:40:15 +0200 | [diff] [blame] | 1071 | if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
| 1072 | st->target = prev_state; |
| 1073 | st->rollback = true; |
| 1074 | cpuhp_kick_ap_work(cpu); |
| 1075 | } |
Thomas Gleixner | 9845817 | 2016-02-26 18:43:25 +0000 | [diff] [blame] | 1076 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1077 | hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE; |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1078 | out: |
Prasad Sodagudi | 0a29343 | 2017-10-13 15:28:58 -0700 | [diff] [blame] | 1079 | trace_cpuhp_latency(cpu, 0, start_time, ret); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1080 | cpu_hotplug_done(); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1081 | /* This post dead nonsense must die */ |
| 1082 | if (!ret && hasdied) |
Thomas Gleixner | 090e77c | 2016-02-26 18:43:23 +0000 | [diff] [blame] | 1083 | cpu_notify_nofail(CPU_POST_DEAD, cpu); |
Thomas Gleixner | a3c901b | 2018-11-25 19:33:39 +0100 | [diff] [blame] | 1084 | arch_smt_update(); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1085 | return ret; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1086 | } |
| 1087 | |
Thomas Gleixner | 373b8de | 2018-05-29 17:49:05 +0200 | [diff] [blame] | 1088 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
| 1089 | { |
| 1090 | if (cpu_hotplug_disabled) |
| 1091 | return -EBUSY; |
| 1092 | return _cpu_down(cpu, 0, target); |
| 1093 | } |
| 1094 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1095 | 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] | 1096 | { |
Heiko Carstens | 9ea09af | 2008-12-22 12:36:30 +0100 | [diff] [blame] | 1097 | int err; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1098 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1099 | cpu_maps_update_begin(); |
Thomas Gleixner | 373b8de | 2018-05-29 17:49:05 +0200 | [diff] [blame] | 1100 | err = cpu_down_maps_locked(cpu, target); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1101 | cpu_maps_update_done(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1102 | return err; |
| 1103 | } |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1104 | int cpu_down(unsigned int cpu) |
| 1105 | { |
| 1106 | return do_cpu_down(cpu, CPUHP_OFFLINE); |
| 1107 | } |
Zhang Rui | b62b8ef | 2008-04-29 02:35:56 -0400 | [diff] [blame] | 1108 | EXPORT_SYMBOL(cpu_down); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1109 | #endif /*CONFIG_HOTPLUG_CPU*/ |
| 1110 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1111 | /** |
Thomas Gleixner | ee1e714 | 2016-08-18 14:57:16 +0200 | [diff] [blame] | 1112 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1113 | * @cpu: cpu that just started |
| 1114 | * |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1115 | * It must be called by the arch code on the new cpu, before the new cpu |
| 1116 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). |
| 1117 | */ |
| 1118 | void notify_cpu_starting(unsigned int cpu) |
| 1119 | { |
| 1120 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1121 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); |
| 1122 | |
Sebastian Andrzej Siewior | 0c6d457 | 2016-08-17 14:21:04 +0200 | [diff] [blame] | 1123 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 1124 | st->booted_once = true; |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1125 | while (st->state < target) { |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1126 | st->state++; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1127 | cpuhp_invoke_callback(cpu, st->state, true, NULL); |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1128 | } |
| 1129 | } |
| 1130 | |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 1131 | /* |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 1132 | * Called from the idle task. Wake up the controlling task which brings the |
| 1133 | * stopper and the hotplug thread of the upcoming CPU up and then delegates |
| 1134 | * the rest of the online bringup to the hotplug thread. |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 1135 | */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1136 | void cpuhp_online_idle(enum cpuhp_state state) |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 1137 | { |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1138 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1139 | |
| 1140 | /* Happens for the boot cpu */ |
| 1141 | if (state != CPUHP_AP_ONLINE_IDLE) |
| 1142 | return; |
| 1143 | |
| 1144 | st->state = CPUHP_AP_ONLINE_IDLE; |
Thomas Gleixner | ceb354b | 2017-07-04 22:20:23 +0200 | [diff] [blame] | 1145 | complete(&st->done); |
Thomas Gleixner | 949338e | 2016-02-26 18:43:35 +0000 | [diff] [blame] | 1146 | } |
| 1147 | |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1148 | /* Requires cpu_add_remove_lock to be held */ |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1149 | 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] | 1150 | { |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1151 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
Suresh Siddha | 3bb5d2e | 2012-04-20 17:08:50 -0700 | [diff] [blame] | 1152 | struct task_struct *idle; |
Thomas Gleixner | 2e1a348 | 2016-02-26 18:43:37 +0000 | [diff] [blame] | 1153 | int ret = 0; |
Prasad Sodagudi | 0a29343 | 2017-10-13 15:28:58 -0700 | [diff] [blame] | 1154 | u64 start_time = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1155 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1156 | cpu_hotplug_begin(); |
Prasad Sodagudi | 0a29343 | 2017-10-13 15:28:58 -0700 | [diff] [blame] | 1157 | if (trace_cpuhp_latency_enabled()) |
| 1158 | start_time = sched_clock(); |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 1159 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1160 | if (!cpu_present(cpu)) { |
Yasuaki Ishimatsu | 5e5041f | 2012-10-23 01:30:54 +0200 | [diff] [blame] | 1161 | ret = -EINVAL; |
| 1162 | goto out; |
| 1163 | } |
| 1164 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1165 | /* |
| 1166 | * The caller of do_cpu_up might have raced with another |
| 1167 | * caller. Ignore it for now. |
| 1168 | */ |
| 1169 | if (st->state >= target) |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 1170 | goto out; |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1171 | |
| 1172 | if (st->state == CPUHP_OFFLINE) { |
| 1173 | /* Let it fail before we try to bring the cpu up */ |
| 1174 | idle = idle_thread_get(cpu); |
| 1175 | if (IS_ERR(idle)) { |
| 1176 | ret = PTR_ERR(idle); |
| 1177 | goto out; |
| 1178 | } |
Suresh Siddha | 3bb5d2e | 2012-04-20 17:08:50 -0700 | [diff] [blame] | 1179 | } |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 1180 | |
Thomas Gleixner | ba99746 | 2016-02-26 18:43:24 +0000 | [diff] [blame] | 1181 | cpuhp_tasks_frozen = tasks_frozen; |
| 1182 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1183 | st->target = target; |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1184 | /* |
| 1185 | * If the current CPU state is in the range of the AP hotplug thread, |
| 1186 | * then we need to kick the thread once more. |
| 1187 | */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1188 | if (st->state > CPUHP_BRINGUP_CPU) { |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1189 | ret = cpuhp_kick_ap_work(cpu); |
| 1190 | /* |
| 1191 | * The AP side has done the error rollback already. Just |
| 1192 | * return the error code.. |
| 1193 | */ |
| 1194 | if (ret) |
| 1195 | goto out; |
| 1196 | } |
| 1197 | |
| 1198 | /* |
| 1199 | * Try to reach the target state. We max out on the BP at |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1200 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1201 | * responsible for bringing it up to the target state. |
| 1202 | */ |
Thomas Gleixner | 8df3e07 | 2016-02-26 18:43:41 +0000 | [diff] [blame] | 1203 | target = min((int)target, CPUHP_BRINGUP_CPU); |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 1204 | ret = cpuhp_up_callbacks(cpu, st, target); |
Thomas Gleixner | 38498a6 | 2012-04-20 13:05:44 +0000 | [diff] [blame] | 1205 | out: |
Prasad Sodagudi | 0a29343 | 2017-10-13 15:28:58 -0700 | [diff] [blame] | 1206 | trace_cpuhp_latency(cpu, 1, start_time, ret); |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1207 | cpu_hotplug_done(); |
Thomas Gleixner | a3c901b | 2018-11-25 19:33:39 +0100 | [diff] [blame] | 1208 | arch_smt_update(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1209 | return ret; |
| 1210 | } |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1211 | |
Syed Rameez Mustafa | b305880 | 2016-12-16 11:59:05 -0800 | [diff] [blame] | 1212 | static int switch_to_rt_policy(void) |
| 1213 | { |
| 1214 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; |
| 1215 | unsigned int policy = current->policy; |
| 1216 | int err; |
| 1217 | |
| 1218 | /* Nobody should be attempting hotplug from these policy contexts. */ |
| 1219 | if (policy == SCHED_BATCH || policy == SCHED_IDLE || |
| 1220 | policy == SCHED_DEADLINE) |
| 1221 | return -EPERM; |
| 1222 | |
| 1223 | if (policy == SCHED_FIFO || policy == SCHED_RR) |
| 1224 | return 1; |
| 1225 | |
| 1226 | /* Only SCHED_NORMAL left. */ |
| 1227 | err = sched_setscheduler_nocheck(current, SCHED_FIFO, ¶m); |
| 1228 | return err; |
| 1229 | |
| 1230 | } |
| 1231 | |
| 1232 | static int switch_to_fair_policy(void) |
| 1233 | { |
| 1234 | struct sched_param param = { .sched_priority = 0 }; |
| 1235 | |
| 1236 | return sched_setscheduler_nocheck(current, SCHED_NORMAL, ¶m); |
| 1237 | } |
| 1238 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1239 | 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] | 1240 | { |
| 1241 | int err = 0; |
Syed Rameez Mustafa | b305880 | 2016-12-16 11:59:05 -0800 | [diff] [blame] | 1242 | int switch_err = 0; |
minskey guo | cf23422 | 2010-05-24 14:32:41 -0700 | [diff] [blame] | 1243 | |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1244 | if (!cpu_possible(cpu)) { |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1245 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
| 1246 | cpu); |
Chen Gong | 87d5e02 | 2010-03-05 13:42:38 -0800 | [diff] [blame] | 1247 | #if defined(CONFIG_IA64) |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1248 | pr_err("please check additional_cpus= boot parameter\n"); |
KAMEZAWA Hiroyuki | 73e753a | 2007-10-18 23:40:47 -0700 | [diff] [blame] | 1249 | #endif |
| 1250 | return -EINVAL; |
| 1251 | } |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1252 | |
Syed Rameez Mustafa | b305880 | 2016-12-16 11:59:05 -0800 | [diff] [blame] | 1253 | switch_err = switch_to_rt_policy(); |
| 1254 | if (switch_err < 0) |
| 1255 | return switch_err; |
| 1256 | |
Toshi Kani | 01b0f19 | 2013-11-12 15:07:25 -0800 | [diff] [blame] | 1257 | err = try_online_node(cpu_to_node(cpu)); |
| 1258 | if (err) |
| 1259 | return err; |
minskey guo | cf23422 | 2010-05-24 14:32:41 -0700 | [diff] [blame] | 1260 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1261 | cpu_maps_update_begin(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1262 | |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 1263 | if (cpu_hotplug_disabled) { |
| 1264 | err = -EBUSY; |
| 1265 | goto out; |
| 1266 | } |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 1267 | if (!cpu_smt_allowed(cpu)) { |
| 1268 | err = -EPERM; |
| 1269 | goto out; |
| 1270 | } |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 1271 | |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1272 | err = _cpu_up(cpu, 0, target); |
Max Krasnyansky | e761b77 | 2008-07-15 04:43:49 -0700 | [diff] [blame] | 1273 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1274 | cpu_maps_update_done(); |
Syed Rameez Mustafa | b305880 | 2016-12-16 11:59:05 -0800 | [diff] [blame] | 1275 | |
| 1276 | if (!switch_err) { |
| 1277 | switch_err = switch_to_fair_policy(); |
Pavankumar Kondeti | 657ad05 | 2017-04-14 14:59:40 +0530 | [diff] [blame] | 1278 | if (switch_err) |
| 1279 | pr_err("Hotplug policy switch err=%d Task %s pid=%d\n", |
| 1280 | switch_err, current->comm, current->pid); |
Syed Rameez Mustafa | b305880 | 2016-12-16 11:59:05 -0800 | [diff] [blame] | 1281 | } |
| 1282 | |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1283 | return err; |
| 1284 | } |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1285 | |
| 1286 | int cpu_up(unsigned int cpu) |
| 1287 | { |
| 1288 | return do_cpu_up(cpu, CPUHP_ONLINE); |
| 1289 | } |
Paul E. McKenney | a513f6b | 2011-12-11 21:54:45 -0800 | [diff] [blame] | 1290 | EXPORT_SYMBOL_GPL(cpu_up); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1291 | |
Rafael J. Wysocki | f3de4be | 2007-08-30 23:56:29 -0700 | [diff] [blame] | 1292 | #ifdef CONFIG_PM_SLEEP_SMP |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1293 | static cpumask_var_t frozen_cpus; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1294 | |
James Morse | d391e55 | 2016-08-17 13:50:25 +0100 | [diff] [blame] | 1295 | int freeze_secondary_cpus(int primary) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1296 | { |
James Morse | d391e55 | 2016-08-17 13:50:25 +0100 | [diff] [blame] | 1297 | int cpu, error = 0; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1298 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1299 | cpu_maps_update_begin(); |
James Morse | d391e55 | 2016-08-17 13:50:25 +0100 | [diff] [blame] | 1300 | if (!cpu_online(primary)) |
| 1301 | primary = cpumask_first(cpu_online_mask); |
Xiaotian Feng | 9ee349a | 2009-12-16 18:04:32 +0100 | [diff] [blame] | 1302 | /* |
| 1303 | * 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] | 1304 | * with the userspace trying to use the CPU hotplug at the same time |
| 1305 | */ |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1306 | cpumask_clear(frozen_cpus); |
Peter Zijlstra | 6ad4c18 | 2009-11-25 13:31:39 +0100 | [diff] [blame] | 1307 | |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1308 | pr_info("Disabling non-boot CPUs ...\n"); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1309 | for_each_online_cpu(cpu) { |
James Morse | d391e55 | 2016-08-17 13:50:25 +0100 | [diff] [blame] | 1310 | if (cpu == primary) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1311 | continue; |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 1312 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1313 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 1314 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
Mike Travis | feae320 | 2009-11-17 18:22:13 -0600 | [diff] [blame] | 1315 | if (!error) |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1316 | cpumask_set_cpu(cpu, frozen_cpus); |
Mike Travis | feae320 | 2009-11-17 18:22:13 -0600 | [diff] [blame] | 1317 | else { |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1318 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1319 | break; |
| 1320 | } |
| 1321 | } |
Joseph Cihula | 86886e5 | 2009-06-30 19:31:07 -0700 | [diff] [blame] | 1322 | |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1323 | if (!error) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1324 | BUG_ON(num_online_cpus() > 1); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1325 | else |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1326 | pr_err("Non-boot CPUs are not disabled\n"); |
Vitaly Kuznetsov | 89af7ba | 2015-08-05 00:52:46 -0700 | [diff] [blame] | 1327 | |
| 1328 | /* |
| 1329 | * Make sure the CPUs won't be enabled by someone else. We need to do |
| 1330 | * this even in case of failure as all disable_nonboot_cpus() users are |
| 1331 | * supposed to do enable_nonboot_cpus() on the failure path. |
| 1332 | */ |
| 1333 | cpu_hotplug_disabled++; |
| 1334 | |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1335 | cpu_maps_update_done(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1336 | return error; |
| 1337 | } |
| 1338 | |
Suresh Siddha | d0af9ee | 2009-08-19 18:05:36 -0700 | [diff] [blame] | 1339 | void __weak arch_enable_nonboot_cpus_begin(void) |
| 1340 | { |
| 1341 | } |
| 1342 | |
| 1343 | void __weak arch_enable_nonboot_cpus_end(void) |
| 1344 | { |
| 1345 | } |
| 1346 | |
Mathias Krause | 71cf5ae | 2015-07-19 20:06:22 +0200 | [diff] [blame] | 1347 | void enable_nonboot_cpus(void) |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1348 | { |
| 1349 | int cpu, error; |
Thierry Strudel | 0c3610e | 2016-06-14 17:46:44 -0700 | [diff] [blame] | 1350 | struct device *cpu_device; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1351 | |
| 1352 | /* Allow everyone to use the CPU hotplug again */ |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1353 | cpu_maps_update_begin(); |
Lianwei Wang | 01b4115 | 2016-06-09 23:43:28 -0700 | [diff] [blame] | 1354 | __cpu_hotplug_enable(); |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1355 | if (cpumask_empty(frozen_cpus)) |
Rafael J. Wysocki | 1d64b9c | 2007-04-01 23:49:49 -0700 | [diff] [blame] | 1356 | goto out; |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1357 | |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1358 | pr_info("Enabling non-boot CPUs ...\n"); |
Suresh Siddha | d0af9ee | 2009-08-19 18:05:36 -0700 | [diff] [blame] | 1359 | |
| 1360 | arch_enable_nonboot_cpus_begin(); |
| 1361 | |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1362 | for_each_cpu(cpu, frozen_cpus) { |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 1363 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
Thomas Gleixner | af1f404 | 2016-02-26 18:43:30 +0000 | [diff] [blame] | 1364 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
Todd E Brandt | bb3632c | 2014-06-06 05:40:17 -0700 | [diff] [blame] | 1365 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1366 | if (!error) { |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1367 | pr_info("CPU%d is up\n", cpu); |
Thierry Strudel | 0c3610e | 2016-06-14 17:46:44 -0700 | [diff] [blame] | 1368 | cpu_device = get_cpu_device(cpu); |
| 1369 | if (!cpu_device) |
| 1370 | pr_err("%s: failed to get cpu%d device\n", |
| 1371 | __func__, cpu); |
| 1372 | else |
| 1373 | kobject_uevent(&cpu_device->kobj, KOBJ_ONLINE); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1374 | continue; |
| 1375 | } |
Fabian Frederick | 84117da | 2014-06-04 16:11:17 -0700 | [diff] [blame] | 1376 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1377 | } |
Suresh Siddha | d0af9ee | 2009-08-19 18:05:36 -0700 | [diff] [blame] | 1378 | |
| 1379 | arch_enable_nonboot_cpus_end(); |
| 1380 | |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1381 | cpumask_clear(frozen_cpus); |
Rafael J. Wysocki | 1d64b9c | 2007-04-01 23:49:49 -0700 | [diff] [blame] | 1382 | out: |
Gautham R Shenoy | d221938 | 2008-01-25 21:08:01 +0100 | [diff] [blame] | 1383 | cpu_maps_update_done(); |
Rafael J. Wysocki | e3920fb | 2006-09-25 23:32:48 -0700 | [diff] [blame] | 1384 | } |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1385 | |
Fenghua Yu | d7268a3 | 2011-11-15 21:59:31 +0100 | [diff] [blame] | 1386 | static int __init alloc_frozen_cpus(void) |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 1387 | { |
| 1388 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) |
| 1389 | return -ENOMEM; |
| 1390 | return 0; |
| 1391 | } |
| 1392 | core_initcall(alloc_frozen_cpus); |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1393 | |
| 1394 | /* |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1395 | * When callbacks for CPU hotplug notifications are being executed, we must |
| 1396 | * ensure that the state of the system with respect to the tasks being frozen |
| 1397 | * or not, as reported by the notification, remains unchanged *throughout the |
| 1398 | * duration* of the execution of the callbacks. |
| 1399 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. |
| 1400 | * |
| 1401 | * This synchronization is implemented by mutually excluding regular CPU |
| 1402 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ |
| 1403 | * Hibernate notifications. |
| 1404 | */ |
| 1405 | static int |
| 1406 | cpu_hotplug_pm_callback(struct notifier_block *nb, |
| 1407 | unsigned long action, void *ptr) |
| 1408 | { |
| 1409 | switch (action) { |
| 1410 | |
| 1411 | case PM_SUSPEND_PREPARE: |
| 1412 | case PM_HIBERNATION_PREPARE: |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 1413 | cpu_hotplug_disable(); |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1414 | break; |
| 1415 | |
| 1416 | case PM_POST_SUSPEND: |
| 1417 | case PM_POST_HIBERNATION: |
Srivatsa S. Bhat | 16e53db | 2013-06-12 14:04:36 -0700 | [diff] [blame] | 1418 | cpu_hotplug_enable(); |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1419 | break; |
| 1420 | |
| 1421 | default: |
| 1422 | return NOTIFY_DONE; |
| 1423 | } |
| 1424 | |
| 1425 | return NOTIFY_OK; |
| 1426 | } |
| 1427 | |
| 1428 | |
Fenghua Yu | d7268a3 | 2011-11-15 21:59:31 +0100 | [diff] [blame] | 1429 | static int __init cpu_hotplug_pm_sync_init(void) |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1430 | { |
Fenghua Yu | 6e32d47 | 2012-11-13 11:32:43 -0800 | [diff] [blame] | 1431 | /* |
| 1432 | * cpu_hotplug_pm_callback has higher priority than x86 |
| 1433 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback |
| 1434 | * to disable cpu hotplug to avoid cpu hotplug race. |
| 1435 | */ |
Srivatsa S. Bhat | 79cfbdf | 2011-11-03 00:59:25 +0100 | [diff] [blame] | 1436 | pm_notifier(cpu_hotplug_pm_callback, 0); |
| 1437 | return 0; |
| 1438 | } |
| 1439 | core_initcall(cpu_hotplug_pm_sync_init); |
| 1440 | |
Rafael J. Wysocki | f3de4be | 2007-08-30 23:56:29 -0700 | [diff] [blame] | 1441 | #endif /* CONFIG_PM_SLEEP_SMP */ |
Max Krasnyansky | 68f4f1e | 2008-05-29 11:17:02 -0700 | [diff] [blame] | 1442 | |
| 1443 | #endif /* CONFIG_SMP */ |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 1444 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1445 | /* Boot processor state steps */ |
| 1446 | static struct cpuhp_step cpuhp_bp_states[] = { |
| 1447 | [CPUHP_OFFLINE] = { |
| 1448 | .name = "offline", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1449 | .startup.single = NULL, |
| 1450 | .teardown.single = NULL, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1451 | }, |
| 1452 | #ifdef CONFIG_SMP |
| 1453 | [CPUHP_CREATE_THREADS]= { |
Thomas Gleixner | 677f664 | 2016-09-06 16:13:48 +0200 | [diff] [blame] | 1454 | .name = "threads:prepare", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1455 | .startup.single = smpboot_create_threads, |
| 1456 | .teardown.single = NULL, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1457 | .cant_stop = true, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1458 | }, |
Thomas Gleixner | 00e16c3 | 2016-07-13 17:16:09 +0000 | [diff] [blame] | 1459 | [CPUHP_PERF_PREPARE] = { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1460 | .name = "perf:prepare", |
| 1461 | .startup.single = perf_event_init_cpu, |
| 1462 | .teardown.single = perf_event_exit_cpu, |
Thomas Gleixner | 00e16c3 | 2016-07-13 17:16:09 +0000 | [diff] [blame] | 1463 | }, |
Thomas Gleixner | 7ee681b | 2016-07-13 17:16:29 +0000 | [diff] [blame] | 1464 | [CPUHP_WORKQUEUE_PREP] = { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1465 | .name = "workqueue:prepare", |
| 1466 | .startup.single = workqueue_prepare_cpu, |
| 1467 | .teardown.single = NULL, |
Thomas Gleixner | 7ee681b | 2016-07-13 17:16:29 +0000 | [diff] [blame] | 1468 | }, |
Thomas Gleixner | 27590dc | 2016-07-15 10:41:04 +0200 | [diff] [blame] | 1469 | [CPUHP_HRTIMERS_PREPARE] = { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1470 | .name = "hrtimers:prepare", |
| 1471 | .startup.single = hrtimers_prepare_cpu, |
| 1472 | .teardown.single = hrtimers_dead_cpu, |
Thomas Gleixner | 27590dc | 2016-07-15 10:41:04 +0200 | [diff] [blame] | 1473 | }, |
Richard Weinberger | 31487f8 | 2016-07-13 17:17:01 +0000 | [diff] [blame] | 1474 | [CPUHP_SMPCFD_PREPARE] = { |
Thomas Gleixner | 677f664 | 2016-09-06 16:13:48 +0200 | [diff] [blame] | 1475 | .name = "smpcfd:prepare", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1476 | .startup.single = smpcfd_prepare_cpu, |
| 1477 | .teardown.single = smpcfd_dead_cpu, |
Richard Weinberger | 31487f8 | 2016-07-13 17:17:01 +0000 | [diff] [blame] | 1478 | }, |
Richard Weinberger | e6d4989 | 2016-08-18 14:57:17 +0200 | [diff] [blame] | 1479 | [CPUHP_RELAY_PREPARE] = { |
| 1480 | .name = "relay:prepare", |
| 1481 | .startup.single = relay_prepare_cpu, |
| 1482 | .teardown.single = NULL, |
| 1483 | }, |
Sebastian Andrzej Siewior | 6731d4f | 2016-08-23 14:53:19 +0200 | [diff] [blame] | 1484 | [CPUHP_SLAB_PREPARE] = { |
| 1485 | .name = "slab:prepare", |
| 1486 | .startup.single = slab_prepare_cpu, |
| 1487 | .teardown.single = slab_dead_cpu, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1488 | }, |
Thomas Gleixner | 4df8374 | 2016-07-13 17:17:03 +0000 | [diff] [blame] | 1489 | [CPUHP_RCUTREE_PREP] = { |
Thomas Gleixner | 677f664 | 2016-09-06 16:13:48 +0200 | [diff] [blame] | 1490 | .name = "RCU/tree:prepare", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1491 | .startup.single = rcutree_prepare_cpu, |
| 1492 | .teardown.single = rcutree_dead_cpu, |
Thomas Gleixner | 4df8374 | 2016-07-13 17:17:03 +0000 | [diff] [blame] | 1493 | }, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1494 | /* |
| 1495 | * Preparatory and dead notifiers. Will be replaced once the notifiers |
| 1496 | * are converted to states. |
| 1497 | */ |
| 1498 | [CPUHP_NOTIFY_PREPARE] = { |
| 1499 | .name = "notify:prepare", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1500 | .startup.single = notify_prepare, |
| 1501 | .teardown.single = notify_dead, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1502 | .cant_stop = true, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1503 | }, |
Richard Cochran | 4fae16d | 2016-07-27 11:08:18 +0200 | [diff] [blame] | 1504 | /* |
| 1505 | * On the tear-down path, timers_dead_cpu() must be invoked |
| 1506 | * before blk_mq_queue_reinit_notify() from notify_dead(), |
| 1507 | * otherwise a RCU stall occurs. |
| 1508 | */ |
Thomas Gleixner | 249d4a9 | 2017-12-27 21:37:25 +0100 | [diff] [blame] | 1509 | [CPUHP_TIMERS_PREPARE] = { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1510 | .name = "timers:dead", |
Thomas Gleixner | 249d4a9 | 2017-12-27 21:37:25 +0100 | [diff] [blame] | 1511 | .startup.single = timers_prepare_cpu, |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1512 | .teardown.single = timers_dead_cpu, |
Richard Cochran | 4fae16d | 2016-07-27 11:08:18 +0200 | [diff] [blame] | 1513 | }, |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1514 | /* Kicks the plugged cpu into life */ |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1515 | [CPUHP_BRINGUP_CPU] = { |
| 1516 | .name = "cpu:bringup", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1517 | .startup.single = bringup_cpu, |
| 1518 | .teardown.single = NULL, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1519 | .cant_stop = true, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1520 | }, |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1521 | /* |
| 1522 | * Handled on controll processor until the plugged processor manages |
| 1523 | * this itself. |
| 1524 | */ |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1525 | [CPUHP_TEARDOWN_CPU] = { |
| 1526 | .name = "cpu:teardown", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1527 | .startup.single = NULL, |
| 1528 | .teardown.single = takedown_cpu, |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1529 | .cant_stop = true, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1530 | }, |
Thomas Gleixner | a7c73414 | 2016-07-12 21:59:23 +0200 | [diff] [blame] | 1531 | #else |
| 1532 | [CPUHP_BRINGUP_CPU] = { }, |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1533 | #endif |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 1534 | }; |
| 1535 | |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1536 | /* Application processor state steps */ |
| 1537 | static struct cpuhp_step cpuhp_ap_states[] = { |
| 1538 | #ifdef CONFIG_SMP |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1539 | /* Final state before CPU kills itself */ |
| 1540 | [CPUHP_AP_IDLE_DEAD] = { |
| 1541 | .name = "idle:dead", |
| 1542 | }, |
| 1543 | /* |
| 1544 | * Last state before CPU enters the idle loop to die. Transient state |
| 1545 | * for synchronization. |
| 1546 | */ |
| 1547 | [CPUHP_AP_OFFLINE] = { |
| 1548 | .name = "ap:offline", |
| 1549 | .cant_stop = true, |
| 1550 | }, |
Thomas Gleixner | 9cf7243 | 2016-03-10 12:54:09 +0100 | [diff] [blame] | 1551 | /* First state is scheduler control. Interrupts are disabled */ |
| 1552 | [CPUHP_AP_SCHED_STARTING] = { |
| 1553 | .name = "sched:starting", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1554 | .startup.single = sched_cpu_starting, |
| 1555 | .teardown.single = sched_cpu_dying, |
Thomas Gleixner | 9cf7243 | 2016-03-10 12:54:09 +0100 | [diff] [blame] | 1556 | }, |
Thomas Gleixner | 4df8374 | 2016-07-13 17:17:03 +0000 | [diff] [blame] | 1557 | [CPUHP_AP_RCUTREE_DYING] = { |
Thomas Gleixner | 677f664 | 2016-09-06 16:13:48 +0200 | [diff] [blame] | 1558 | .name = "RCU/tree:dying", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1559 | .startup.single = NULL, |
| 1560 | .teardown.single = rcutree_dying_cpu, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1561 | }, |
Maria Yu | e90f8e1 | 2017-09-21 11:30:53 +0800 | [diff] [blame] | 1562 | [CPUHP_AP_KMAP_DYING] = { |
| 1563 | .name = "KMAP:dying", |
| 1564 | .startup.single = NULL, |
| 1565 | .teardown.single = kmap_remove_unused_cpu, |
| 1566 | }, |
Lai Jiangshan | ff3d4fd | 2017-11-28 21:19:53 +0800 | [diff] [blame] | 1567 | [CPUHP_AP_SMPCFD_DYING] = { |
| 1568 | .name = "smpcfd:dying", |
| 1569 | .startup.single = NULL, |
| 1570 | .teardown.single = smpcfd_dying_cpu, |
| 1571 | }, |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1572 | /* Entry state on starting. Interrupts enabled from here on. Transient |
| 1573 | * state for synchronsization */ |
| 1574 | [CPUHP_AP_ONLINE] = { |
| 1575 | .name = "ap:online", |
| 1576 | }, |
| 1577 | /* Handle smpboot threads park/unpark */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1578 | [CPUHP_AP_SMPBOOT_THREADS] = { |
Thomas Gleixner | 677f664 | 2016-09-06 16:13:48 +0200 | [diff] [blame] | 1579 | .name = "smpboot/threads:online", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1580 | .startup.single = smpboot_unpark_threads, |
Thomas Gleixner | 9333575 | 2018-05-29 19:05:25 +0200 | [diff] [blame] | 1581 | .teardown.single = smpboot_park_threads, |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1582 | }, |
Thomas Gleixner | 00e16c3 | 2016-07-13 17:16:09 +0000 | [diff] [blame] | 1583 | [CPUHP_AP_PERF_ONLINE] = { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1584 | .name = "perf:online", |
Raghavendra Rao Ananta | 595428c | 2018-10-16 12:13:22 -0700 | [diff] [blame] | 1585 | .startup.single = perf_event_restart_events, |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1586 | .teardown.single = perf_event_exit_cpu, |
Thomas Gleixner | 00e16c3 | 2016-07-13 17:16:09 +0000 | [diff] [blame] | 1587 | }, |
Thomas Gleixner | 7ee681b | 2016-07-13 17:16:29 +0000 | [diff] [blame] | 1588 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1589 | .name = "workqueue:online", |
| 1590 | .startup.single = workqueue_online_cpu, |
| 1591 | .teardown.single = workqueue_offline_cpu, |
Thomas Gleixner | 7ee681b | 2016-07-13 17:16:29 +0000 | [diff] [blame] | 1592 | }, |
Thomas Gleixner | 4df8374 | 2016-07-13 17:17:03 +0000 | [diff] [blame] | 1593 | [CPUHP_AP_RCUTREE_ONLINE] = { |
Thomas Gleixner | 677f664 | 2016-09-06 16:13:48 +0200 | [diff] [blame] | 1594 | .name = "RCU/tree:online", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1595 | .startup.single = rcutree_online_cpu, |
| 1596 | .teardown.single = rcutree_offline_cpu, |
Thomas Gleixner | 4df8374 | 2016-07-13 17:17:03 +0000 | [diff] [blame] | 1597 | }, |
Thomas Gleixner | 00e16c3 | 2016-07-13 17:16:09 +0000 | [diff] [blame] | 1598 | |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1599 | /* |
| 1600 | * Online/down_prepare notifiers. Will be removed once the notifiers |
| 1601 | * are converted to states. |
| 1602 | */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1603 | [CPUHP_AP_NOTIFY_ONLINE] = { |
| 1604 | .name = "notify:online", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1605 | .startup.single = notify_online, |
| 1606 | .teardown.single = notify_down_prepare, |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1607 | }, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1608 | #endif |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1609 | /* |
| 1610 | * The dynamically registered state space is here |
| 1611 | */ |
| 1612 | |
Thomas Gleixner | aaddd7d | 2016-03-10 12:54:19 +0100 | [diff] [blame] | 1613 | #ifdef CONFIG_SMP |
| 1614 | /* Last state is scheduler control setting the cpu active */ |
| 1615 | [CPUHP_AP_ACTIVE] = { |
| 1616 | .name = "sched:active", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1617 | .startup.single = sched_cpu_activate, |
| 1618 | .teardown.single = sched_cpu_deactivate, |
Thomas Gleixner | aaddd7d | 2016-03-10 12:54:19 +0100 | [diff] [blame] | 1619 | }, |
| 1620 | #endif |
| 1621 | |
Thomas Gleixner | d10ef6f | 2016-03-08 10:36:13 +0100 | [diff] [blame] | 1622 | /* CPU is fully up and running. */ |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1623 | [CPUHP_ONLINE] = { |
| 1624 | .name = "online", |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1625 | .startup.single = NULL, |
| 1626 | .teardown.single = NULL, |
Thomas Gleixner | 4baa0af | 2016-02-26 18:43:29 +0000 | [diff] [blame] | 1627 | }, |
| 1628 | }; |
| 1629 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1630 | /* Sanity check for callbacks */ |
| 1631 | static int cpuhp_cb_check(enum cpuhp_state state) |
| 1632 | { |
| 1633 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) |
| 1634 | return -EINVAL; |
| 1635 | return 0; |
| 1636 | } |
| 1637 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1638 | static void cpuhp_store_callbacks(enum cpuhp_state state, |
| 1639 | const char *name, |
| 1640 | int (*startup)(unsigned int cpu), |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1641 | int (*teardown)(unsigned int cpu), |
| 1642 | bool multi_instance) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1643 | { |
| 1644 | /* (Un)Install the callbacks for further cpu hotplug operations */ |
| 1645 | struct cpuhp_step *sp; |
| 1646 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1647 | sp = cpuhp_get_step(state); |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1648 | sp->startup.single = startup; |
| 1649 | sp->teardown.single = teardown; |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1650 | sp->name = name; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1651 | sp->multi_instance = multi_instance; |
| 1652 | INIT_HLIST_HEAD(&sp->list); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1653 | } |
| 1654 | |
| 1655 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) |
| 1656 | { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1657 | return cpuhp_get_step(state)->teardown.single; |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1658 | } |
| 1659 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1660 | /* |
| 1661 | * Call the startup/teardown function for a step either on the AP or |
| 1662 | * on the current CPU. |
| 1663 | */ |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1664 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
| 1665 | struct hlist_node *node) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1666 | { |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 1667 | struct cpuhp_step *sp = cpuhp_get_step(state); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1668 | int ret; |
| 1669 | |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1670 | if ((bringup && !sp->startup.single) || |
| 1671 | (!bringup && !sp->teardown.single)) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1672 | return 0; |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1673 | /* |
| 1674 | * The non AP bound callbacks can fail on bringup. On teardown |
| 1675 | * e.g. module removal we crash for now. |
| 1676 | */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1677 | #ifdef CONFIG_SMP |
| 1678 | if (cpuhp_is_ap_state(state)) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1679 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1680 | else |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1681 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1682 | #else |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1683 | ret = cpuhp_invoke_callback(cpu, state, bringup, node); |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1684 | #endif |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1685 | BUG_ON(ret && !bringup); |
| 1686 | return ret; |
| 1687 | } |
| 1688 | |
| 1689 | /* |
| 1690 | * Called from __cpuhp_setup_state on a recoverable failure. |
| 1691 | * |
| 1692 | * Note: The teardown callbacks for rollback are not allowed to fail! |
| 1693 | */ |
| 1694 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1695 | struct hlist_node *node) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1696 | { |
| 1697 | int cpu; |
| 1698 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1699 | /* Roll back the already executed steps on the other cpus */ |
| 1700 | for_each_present_cpu(cpu) { |
| 1701 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1702 | int cpustate = st->state; |
| 1703 | |
| 1704 | if (cpu >= failedcpu) |
| 1705 | break; |
| 1706 | |
| 1707 | /* Did we invoke the startup call on that cpu ? */ |
| 1708 | if (cpustate >= state) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1709 | cpuhp_issue_call(cpu, state, false, node); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1710 | } |
| 1711 | } |
| 1712 | |
| 1713 | /* |
| 1714 | * Returns a free for dynamic slot assignment of the Online state. The states |
| 1715 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified |
| 1716 | * by having no name assigned. |
| 1717 | */ |
| 1718 | static int cpuhp_reserve_state(enum cpuhp_state state) |
| 1719 | { |
| 1720 | enum cpuhp_state i; |
| 1721 | |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1722 | for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) { |
| 1723 | if (cpuhp_ap_states[i].name) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1724 | continue; |
| 1725 | |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1726 | cpuhp_ap_states[i].name = "Reserved"; |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1727 | return i; |
| 1728 | } |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1729 | WARN(1, "No more dynamic states available for CPU hotplug\n"); |
| 1730 | return -ENOSPC; |
| 1731 | } |
| 1732 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1733 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, |
| 1734 | bool invoke) |
| 1735 | { |
| 1736 | struct cpuhp_step *sp; |
| 1737 | int cpu; |
| 1738 | int ret; |
| 1739 | |
| 1740 | sp = cpuhp_get_step(state); |
| 1741 | if (sp->multi_instance == false) |
| 1742 | return -EINVAL; |
| 1743 | |
| 1744 | get_online_cpus(); |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1745 | mutex_lock(&cpuhp_state_mutex); |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1746 | |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1747 | if (!invoke || !sp->startup.multi) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1748 | goto add_node; |
| 1749 | |
| 1750 | /* |
| 1751 | * Try to call the startup callback for each present cpu |
| 1752 | * depending on the hotplug state of the cpu. |
| 1753 | */ |
| 1754 | for_each_present_cpu(cpu) { |
| 1755 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1756 | int cpustate = st->state; |
| 1757 | |
| 1758 | if (cpustate < state) |
| 1759 | continue; |
| 1760 | |
| 1761 | ret = cpuhp_issue_call(cpu, state, true, node); |
| 1762 | if (ret) { |
Thomas Gleixner | 3c1627e | 2016-09-05 15:28:36 +0200 | [diff] [blame] | 1763 | if (sp->teardown.multi) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1764 | cpuhp_rollback_install(cpu, state, node); |
| 1765 | goto err; |
| 1766 | } |
| 1767 | } |
| 1768 | add_node: |
| 1769 | ret = 0; |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1770 | hlist_add_head(node, &sp->list); |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1771 | |
| 1772 | err: |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1773 | mutex_unlock(&cpuhp_state_mutex); |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1774 | put_online_cpus(); |
| 1775 | return ret; |
| 1776 | } |
| 1777 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); |
| 1778 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1779 | /** |
| 1780 | * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state |
| 1781 | * @state: The state to setup |
| 1782 | * @invoke: If true, the startup function is invoked for cpus where |
| 1783 | * cpu state >= @state |
| 1784 | * @startup: startup callback function |
| 1785 | * @teardown: teardown callback function |
| 1786 | * |
| 1787 | * Returns 0 if successful, otherwise a proper error code |
| 1788 | */ |
| 1789 | int __cpuhp_setup_state(enum cpuhp_state state, |
| 1790 | const char *name, bool invoke, |
| 1791 | int (*startup)(unsigned int cpu), |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1792 | int (*teardown)(unsigned int cpu), |
| 1793 | bool multi_instance) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1794 | { |
| 1795 | int cpu, ret = 0; |
| 1796 | int dyn_state = 0; |
| 1797 | |
| 1798 | if (cpuhp_cb_check(state) || !name) |
| 1799 | return -EINVAL; |
| 1800 | |
| 1801 | get_online_cpus(); |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1802 | mutex_lock(&cpuhp_state_mutex); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1803 | |
| 1804 | /* currently assignments for the ONLINE state are possible */ |
Thomas Gleixner | 1cf4f62 | 2016-02-26 18:43:39 +0000 | [diff] [blame] | 1805 | if (state == CPUHP_AP_ONLINE_DYN) { |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1806 | dyn_state = 1; |
| 1807 | ret = cpuhp_reserve_state(state); |
| 1808 | if (ret < 0) |
| 1809 | goto out; |
| 1810 | state = ret; |
| 1811 | } |
| 1812 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1813 | cpuhp_store_callbacks(state, name, startup, teardown, multi_instance); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1814 | |
| 1815 | if (!invoke || !startup) |
| 1816 | goto out; |
| 1817 | |
| 1818 | /* |
| 1819 | * Try to call the startup callback for each present cpu |
| 1820 | * depending on the hotplug state of the cpu. |
| 1821 | */ |
| 1822 | for_each_present_cpu(cpu) { |
| 1823 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1824 | int cpustate = st->state; |
| 1825 | |
| 1826 | if (cpustate < state) |
| 1827 | continue; |
| 1828 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1829 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1830 | if (ret) { |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 1831 | if (teardown) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1832 | cpuhp_rollback_install(cpu, state, NULL); |
| 1833 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1834 | goto out; |
| 1835 | } |
| 1836 | } |
| 1837 | out: |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1838 | mutex_unlock(&cpuhp_state_mutex); |
| 1839 | |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1840 | put_online_cpus(); |
| 1841 | if (!ret && dyn_state) |
| 1842 | return state; |
| 1843 | return ret; |
| 1844 | } |
| 1845 | EXPORT_SYMBOL(__cpuhp_setup_state); |
| 1846 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1847 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
| 1848 | struct hlist_node *node, bool invoke) |
| 1849 | { |
| 1850 | struct cpuhp_step *sp = cpuhp_get_step(state); |
| 1851 | int cpu; |
| 1852 | |
| 1853 | BUG_ON(cpuhp_cb_check(state)); |
| 1854 | |
| 1855 | if (!sp->multi_instance) |
| 1856 | return -EINVAL; |
| 1857 | |
| 1858 | get_online_cpus(); |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1859 | mutex_lock(&cpuhp_state_mutex); |
| 1860 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1861 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
| 1862 | goto remove; |
| 1863 | /* |
| 1864 | * Call the teardown callback for each present cpu depending |
| 1865 | * on the hotplug state of the cpu. This function is not |
| 1866 | * allowed to fail currently! |
| 1867 | */ |
| 1868 | for_each_present_cpu(cpu) { |
| 1869 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1870 | int cpustate = st->state; |
| 1871 | |
| 1872 | if (cpustate >= state) |
| 1873 | cpuhp_issue_call(cpu, state, false, node); |
| 1874 | } |
| 1875 | |
| 1876 | remove: |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1877 | hlist_del(node); |
| 1878 | mutex_unlock(&cpuhp_state_mutex); |
| 1879 | put_online_cpus(); |
| 1880 | |
| 1881 | return 0; |
| 1882 | } |
| 1883 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1884 | /** |
| 1885 | * __cpuhp_remove_state - Remove the callbacks for an hotplug machine state |
| 1886 | * @state: The state to remove |
| 1887 | * @invoke: If true, the teardown function is invoked for cpus where |
| 1888 | * cpu state >= @state |
| 1889 | * |
| 1890 | * The teardown callback is currently not allowed to fail. Think |
| 1891 | * about module removal! |
| 1892 | */ |
| 1893 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) |
| 1894 | { |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1895 | struct cpuhp_step *sp = cpuhp_get_step(state); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1896 | int cpu; |
| 1897 | |
| 1898 | BUG_ON(cpuhp_cb_check(state)); |
| 1899 | |
| 1900 | get_online_cpus(); |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1901 | mutex_lock(&cpuhp_state_mutex); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1902 | |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1903 | if (sp->multi_instance) { |
| 1904 | WARN(!hlist_empty(&sp->list), |
| 1905 | "Error: Removing state %d which has instances left.\n", |
| 1906 | state); |
| 1907 | goto remove; |
| 1908 | } |
| 1909 | |
Thomas Gleixner | a724632 | 2016-08-12 19:49:38 +0200 | [diff] [blame] | 1910 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1911 | goto remove; |
| 1912 | |
| 1913 | /* |
| 1914 | * Call the teardown callback for each present cpu depending |
| 1915 | * on the hotplug state of the cpu. This function is not |
| 1916 | * allowed to fail currently! |
| 1917 | */ |
| 1918 | for_each_present_cpu(cpu) { |
| 1919 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| 1920 | int cpustate = st->state; |
| 1921 | |
| 1922 | if (cpustate >= state) |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1923 | cpuhp_issue_call(cpu, state, false, NULL); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1924 | } |
| 1925 | remove: |
Thomas Gleixner | cf392d1 | 2016-08-12 19:49:39 +0200 | [diff] [blame] | 1926 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
Sebastian Andrzej Siewior | 7ad6de4 | 2017-03-14 16:06:45 +0100 | [diff] [blame] | 1927 | mutex_unlock(&cpuhp_state_mutex); |
Thomas Gleixner | 5b7aa87 | 2016-02-26 18:43:33 +0000 | [diff] [blame] | 1928 | put_online_cpus(); |
| 1929 | } |
| 1930 | EXPORT_SYMBOL(__cpuhp_remove_state); |
| 1931 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1932 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
| 1933 | static ssize_t show_cpuhp_state(struct device *dev, |
| 1934 | struct device_attribute *attr, char *buf) |
| 1935 | { |
| 1936 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1937 | |
| 1938 | return sprintf(buf, "%d\n", st->state); |
| 1939 | } |
| 1940 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); |
| 1941 | |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1942 | static ssize_t write_cpuhp_target(struct device *dev, |
| 1943 | struct device_attribute *attr, |
| 1944 | const char *buf, size_t count) |
| 1945 | { |
| 1946 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1947 | struct cpuhp_step *sp; |
| 1948 | int target, ret; |
| 1949 | |
| 1950 | ret = kstrtoint(buf, 10, &target); |
| 1951 | if (ret) |
| 1952 | return ret; |
| 1953 | |
| 1954 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL |
| 1955 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) |
| 1956 | return -EINVAL; |
| 1957 | #else |
| 1958 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) |
| 1959 | return -EINVAL; |
| 1960 | #endif |
| 1961 | |
| 1962 | ret = lock_device_hotplug_sysfs(); |
| 1963 | if (ret) |
| 1964 | return ret; |
| 1965 | |
| 1966 | mutex_lock(&cpuhp_state_mutex); |
| 1967 | sp = cpuhp_get_step(target); |
| 1968 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; |
| 1969 | mutex_unlock(&cpuhp_state_mutex); |
| 1970 | if (ret) |
Sebastian Andrzej Siewior | 106c77e | 2017-06-02 16:27:14 +0200 | [diff] [blame] | 1971 | goto out; |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1972 | |
| 1973 | if (st->state < target) |
| 1974 | ret = do_cpu_up(dev->id, target); |
| 1975 | else |
| 1976 | ret = do_cpu_down(dev->id, target); |
Sebastian Andrzej Siewior | 106c77e | 2017-06-02 16:27:14 +0200 | [diff] [blame] | 1977 | out: |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1978 | unlock_device_hotplug(); |
| 1979 | return ret ? ret : count; |
| 1980 | } |
| 1981 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1982 | static ssize_t show_cpuhp_target(struct device *dev, |
| 1983 | struct device_attribute *attr, char *buf) |
| 1984 | { |
| 1985 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| 1986 | |
| 1987 | return sprintf(buf, "%d\n", st->target); |
| 1988 | } |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 1989 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 1990 | |
| 1991 | static struct attribute *cpuhp_cpu_attrs[] = { |
| 1992 | &dev_attr_state.attr, |
| 1993 | &dev_attr_target.attr, |
| 1994 | NULL |
| 1995 | }; |
| 1996 | |
| 1997 | static struct attribute_group cpuhp_cpu_attr_group = { |
| 1998 | .attrs = cpuhp_cpu_attrs, |
| 1999 | .name = "hotplug", |
| 2000 | NULL |
| 2001 | }; |
| 2002 | |
| 2003 | static ssize_t show_cpuhp_states(struct device *dev, |
| 2004 | struct device_attribute *attr, char *buf) |
| 2005 | { |
| 2006 | ssize_t cur, res = 0; |
| 2007 | int i; |
| 2008 | |
| 2009 | mutex_lock(&cpuhp_state_mutex); |
Thomas Gleixner | 757c989 | 2016-02-26 18:43:32 +0000 | [diff] [blame] | 2010 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 2011 | struct cpuhp_step *sp = cpuhp_get_step(i); |
| 2012 | |
| 2013 | if (sp->name) { |
| 2014 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); |
| 2015 | buf += cur; |
| 2016 | res += cur; |
| 2017 | } |
| 2018 | } |
| 2019 | mutex_unlock(&cpuhp_state_mutex); |
| 2020 | return res; |
| 2021 | } |
| 2022 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); |
| 2023 | |
| 2024 | static struct attribute *cpuhp_cpu_root_attrs[] = { |
| 2025 | &dev_attr_states.attr, |
| 2026 | NULL |
| 2027 | }; |
| 2028 | |
| 2029 | static struct attribute_group cpuhp_cpu_root_attr_group = { |
| 2030 | .attrs = cpuhp_cpu_root_attrs, |
| 2031 | .name = "hotplug", |
| 2032 | NULL |
| 2033 | }; |
| 2034 | |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2035 | #ifdef CONFIG_HOTPLUG_SMT |
| 2036 | |
| 2037 | static const char *smt_states[] = { |
| 2038 | [CPU_SMT_ENABLED] = "on", |
| 2039 | [CPU_SMT_DISABLED] = "off", |
| 2040 | [CPU_SMT_FORCE_DISABLED] = "forceoff", |
| 2041 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", |
| 2042 | }; |
| 2043 | |
| 2044 | static ssize_t |
| 2045 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) |
| 2046 | { |
| 2047 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); |
| 2048 | } |
| 2049 | |
| 2050 | static void cpuhp_offline_cpu_device(unsigned int cpu) |
| 2051 | { |
| 2052 | struct device *dev = get_cpu_device(cpu); |
| 2053 | |
| 2054 | dev->offline = true; |
| 2055 | /* Tell user space about the state change */ |
| 2056 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); |
| 2057 | } |
| 2058 | |
Thomas Gleixner | e7cda2f | 2018-07-07 11:40:18 +0200 | [diff] [blame] | 2059 | static void cpuhp_online_cpu_device(unsigned int cpu) |
| 2060 | { |
| 2061 | struct device *dev = get_cpu_device(cpu); |
| 2062 | |
| 2063 | dev->offline = false; |
| 2064 | /* Tell user space about the state change */ |
| 2065 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); |
| 2066 | } |
| 2067 | |
Jiri Kosina | 5bdc536 | 2019-05-30 00:09:39 +0200 | [diff] [blame] | 2068 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2069 | { |
| 2070 | int cpu, ret = 0; |
| 2071 | |
| 2072 | cpu_maps_update_begin(); |
| 2073 | for_each_online_cpu(cpu) { |
| 2074 | if (topology_is_primary_thread(cpu)) |
| 2075 | continue; |
| 2076 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); |
| 2077 | if (ret) |
| 2078 | break; |
| 2079 | /* |
| 2080 | * As this needs to hold the cpu maps lock it's impossible |
| 2081 | * to call device_offline() because that ends up calling |
| 2082 | * cpu_down() which takes cpu maps lock. cpu maps lock |
| 2083 | * needs to be held as this might race against in kernel |
| 2084 | * abusers of the hotplug machinery (thermal management). |
| 2085 | * |
| 2086 | * So nothing would update device:offline state. That would |
| 2087 | * leave the sysfs entry stale and prevent onlining after |
| 2088 | * smt control has been changed to 'off' again. This is |
| 2089 | * called under the sysfs hotplug lock, so it is properly |
| 2090 | * serialized against the regular offline usage. |
| 2091 | */ |
| 2092 | cpuhp_offline_cpu_device(cpu); |
| 2093 | } |
Jiri Kosina | b410c57 | 2018-09-25 14:38:55 +0200 | [diff] [blame] | 2094 | if (!ret) { |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2095 | cpu_smt_control = ctrlval; |
Jiri Kosina | b410c57 | 2018-09-25 14:38:55 +0200 | [diff] [blame] | 2096 | arch_smt_update(); |
| 2097 | } |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2098 | cpu_maps_update_done(); |
| 2099 | return ret; |
| 2100 | } |
| 2101 | |
Jiri Kosina | 5bdc536 | 2019-05-30 00:09:39 +0200 | [diff] [blame] | 2102 | int cpuhp_smt_enable(void) |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2103 | { |
Thomas Gleixner | e7cda2f | 2018-07-07 11:40:18 +0200 | [diff] [blame] | 2104 | int cpu, ret = 0; |
| 2105 | |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2106 | cpu_maps_update_begin(); |
| 2107 | cpu_smt_control = CPU_SMT_ENABLED; |
Jiri Kosina | b410c57 | 2018-09-25 14:38:55 +0200 | [diff] [blame] | 2108 | arch_smt_update(); |
Thomas Gleixner | e7cda2f | 2018-07-07 11:40:18 +0200 | [diff] [blame] | 2109 | for_each_present_cpu(cpu) { |
| 2110 | /* Skip online CPUs and CPUs on offline nodes */ |
| 2111 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) |
| 2112 | continue; |
| 2113 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); |
| 2114 | if (ret) |
| 2115 | break; |
| 2116 | /* See comment in cpuhp_smt_disable() */ |
| 2117 | cpuhp_online_cpu_device(cpu); |
| 2118 | } |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2119 | cpu_maps_update_done(); |
Thomas Gleixner | e7cda2f | 2018-07-07 11:40:18 +0200 | [diff] [blame] | 2120 | return ret; |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2121 | } |
| 2122 | |
| 2123 | static ssize_t |
| 2124 | store_smt_control(struct device *dev, struct device_attribute *attr, |
| 2125 | const char *buf, size_t count) |
| 2126 | { |
| 2127 | int ctrlval, ret; |
| 2128 | |
| 2129 | if (sysfs_streq(buf, "on")) |
| 2130 | ctrlval = CPU_SMT_ENABLED; |
| 2131 | else if (sysfs_streq(buf, "off")) |
| 2132 | ctrlval = CPU_SMT_DISABLED; |
| 2133 | else if (sysfs_streq(buf, "forceoff")) |
| 2134 | ctrlval = CPU_SMT_FORCE_DISABLED; |
| 2135 | else |
| 2136 | return -EINVAL; |
| 2137 | |
| 2138 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) |
| 2139 | return -EPERM; |
| 2140 | |
| 2141 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) |
| 2142 | return -ENODEV; |
| 2143 | |
| 2144 | ret = lock_device_hotplug_sysfs(); |
| 2145 | if (ret) |
| 2146 | return ret; |
| 2147 | |
| 2148 | if (ctrlval != cpu_smt_control) { |
| 2149 | switch (ctrlval) { |
| 2150 | case CPU_SMT_ENABLED: |
Thomas Gleixner | e7cda2f | 2018-07-07 11:40:18 +0200 | [diff] [blame] | 2151 | ret = cpuhp_smt_enable(); |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2152 | break; |
| 2153 | case CPU_SMT_DISABLED: |
| 2154 | case CPU_SMT_FORCE_DISABLED: |
| 2155 | ret = cpuhp_smt_disable(ctrlval); |
| 2156 | break; |
| 2157 | } |
| 2158 | } |
| 2159 | |
| 2160 | unlock_device_hotplug(); |
| 2161 | return ret ? ret : count; |
| 2162 | } |
| 2163 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
| 2164 | |
| 2165 | static ssize_t |
| 2166 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) |
| 2167 | { |
| 2168 | bool active = topology_max_smt_threads() > 1; |
| 2169 | |
| 2170 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); |
| 2171 | } |
| 2172 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); |
| 2173 | |
| 2174 | static struct attribute *cpuhp_smt_attrs[] = { |
| 2175 | &dev_attr_control.attr, |
| 2176 | &dev_attr_active.attr, |
| 2177 | NULL |
| 2178 | }; |
| 2179 | |
| 2180 | static const struct attribute_group cpuhp_smt_attr_group = { |
| 2181 | .attrs = cpuhp_smt_attrs, |
| 2182 | .name = "smt", |
| 2183 | NULL |
| 2184 | }; |
| 2185 | |
| 2186 | static int __init cpu_smt_state_init(void) |
| 2187 | { |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2188 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
| 2189 | &cpuhp_smt_attr_group); |
| 2190 | } |
| 2191 | |
| 2192 | #else |
| 2193 | static inline int cpu_smt_state_init(void) { return 0; } |
| 2194 | #endif |
| 2195 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 2196 | static int __init cpuhp_sysfs_init(void) |
| 2197 | { |
| 2198 | int cpu, ret; |
| 2199 | |
Thomas Gleixner | f37486c | 2018-05-29 17:48:27 +0200 | [diff] [blame] | 2200 | ret = cpu_smt_state_init(); |
| 2201 | if (ret) |
| 2202 | return ret; |
| 2203 | |
Thomas Gleixner | 98f8cdc | 2016-02-26 18:43:31 +0000 | [diff] [blame] | 2204 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
| 2205 | &cpuhp_cpu_root_attr_group); |
| 2206 | if (ret) |
| 2207 | return ret; |
| 2208 | |
| 2209 | for_each_possible_cpu(cpu) { |
| 2210 | struct device *dev = get_cpu_device(cpu); |
| 2211 | |
| 2212 | if (!dev) |
| 2213 | continue; |
| 2214 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); |
| 2215 | if (ret) |
| 2216 | return ret; |
| 2217 | } |
| 2218 | return 0; |
| 2219 | } |
| 2220 | device_initcall(cpuhp_sysfs_init); |
| 2221 | #endif |
| 2222 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 2223 | /* |
| 2224 | * cpu_bit_bitmap[] is a special, "compressed" data structure that |
| 2225 | * represents all NR_CPUS bits binary values of 1<<nr. |
| 2226 | * |
Rusty Russell | e0b582e | 2009-01-01 10:12:28 +1030 | [diff] [blame] | 2227 | * 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] | 2228 | * mask value that has a single bit set only. |
| 2229 | */ |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 2230 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 2231 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
Michael Rodriguez | 4d51985 | 2011-03-22 16:34:07 -0700 | [diff] [blame] | 2232 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 2233 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
| 2234 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) |
| 2235 | #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] | 2236 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 2237 | 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] | 2238 | |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 2239 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), |
| 2240 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), |
| 2241 | #if BITS_PER_LONG > 32 |
| 2242 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), |
| 2243 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), |
Mike Travis | b8d317d | 2008-07-24 18:21:29 -0700 | [diff] [blame] | 2244 | #endif |
| 2245 | }; |
Linus Torvalds | e56b3bc | 2008-07-28 11:32:33 -0700 | [diff] [blame] | 2246 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
Rusty Russell | 2d3854a | 2008-11-05 13:39:10 +1100 | [diff] [blame] | 2247 | |
| 2248 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; |
| 2249 | EXPORT_SYMBOL(cpu_all_bits); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 2250 | |
| 2251 | #ifdef CONFIG_INIT_ALL_POSSIBLE |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 2252 | struct cpumask __cpu_possible_mask __read_mostly |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 2253 | = {CPU_BITS_ALL}; |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 2254 | #else |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 2255 | struct cpumask __cpu_possible_mask __read_mostly; |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 2256 | #endif |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 2257 | EXPORT_SYMBOL(__cpu_possible_mask); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 2258 | |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 2259 | struct cpumask __cpu_online_mask __read_mostly; |
| 2260 | EXPORT_SYMBOL(__cpu_online_mask); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 2261 | |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 2262 | struct cpumask __cpu_present_mask __read_mostly; |
| 2263 | EXPORT_SYMBOL(__cpu_present_mask); |
Rusty Russell | b3199c0 | 2008-12-30 09:05:14 +1030 | [diff] [blame] | 2264 | |
Rasmus Villemoes | 4b804c8 | 2016-01-20 15:00:19 -0800 | [diff] [blame] | 2265 | struct cpumask __cpu_active_mask __read_mostly; |
| 2266 | EXPORT_SYMBOL(__cpu_active_mask); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 2267 | |
Olav Haugan | 99cd46a | 2016-05-29 19:56:37 -0700 | [diff] [blame] | 2268 | struct cpumask __cpu_isolated_mask __read_mostly; |
| 2269 | EXPORT_SYMBOL(__cpu_isolated_mask); |
| 2270 | |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 2271 | void init_cpu_present(const struct cpumask *src) |
| 2272 | { |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 2273 | cpumask_copy(&__cpu_present_mask, src); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 2274 | } |
| 2275 | |
| 2276 | void init_cpu_possible(const struct cpumask *src) |
| 2277 | { |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 2278 | cpumask_copy(&__cpu_possible_mask, src); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 2279 | } |
| 2280 | |
| 2281 | void init_cpu_online(const struct cpumask *src) |
| 2282 | { |
Rasmus Villemoes | c4c54dd | 2016-01-20 15:00:16 -0800 | [diff] [blame] | 2283 | cpumask_copy(&__cpu_online_mask, src); |
Rusty Russell | 3fa4152 | 2008-12-30 09:05:16 +1030 | [diff] [blame] | 2284 | } |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 2285 | |
Olav Haugan | 99cd46a | 2016-05-29 19:56:37 -0700 | [diff] [blame] | 2286 | void init_cpu_isolated(const struct cpumask *src) |
| 2287 | { |
| 2288 | cpumask_copy(&__cpu_isolated_mask, src); |
| 2289 | } |
| 2290 | |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 2291 | /* |
| 2292 | * Activate the first processor. |
| 2293 | */ |
| 2294 | void __init boot_cpu_init(void) |
| 2295 | { |
| 2296 | int cpu = smp_processor_id(); |
| 2297 | |
| 2298 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ |
| 2299 | set_cpu_online(cpu, true); |
| 2300 | set_cpu_active(cpu, true); |
| 2301 | set_cpu_present(cpu, true); |
| 2302 | set_cpu_possible(cpu, true); |
| 2303 | } |
| 2304 | |
| 2305 | /* |
| 2306 | * Must be called _AFTER_ setting up the per_cpu areas |
| 2307 | */ |
Linus Torvalds | 6bb53ee | 2018-08-12 12:19:42 -0700 | [diff] [blame] | 2308 | void __init boot_cpu_hotplug_init(void) |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 2309 | { |
Abel Vesa | aee0861 | 2018-08-15 00:26:00 +0300 | [diff] [blame] | 2310 | #ifdef CONFIG_SMP |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 2311 | this_cpu_write(cpuhp_state.booted_once, true); |
Abel Vesa | aee0861 | 2018-08-15 00:26:00 +0300 | [diff] [blame] | 2312 | #endif |
Thomas Gleixner | 8438e49 | 2018-06-29 16:05:48 +0200 | [diff] [blame] | 2313 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
Thomas Gleixner | cff7d37 | 2016-02-26 18:43:28 +0000 | [diff] [blame] | 2314 | } |
Todd Poynor | ef07e9e4 | 2011-06-15 17:21:57 -0700 | [diff] [blame] | 2315 | |
Tyler Hicks | e2bd077 | 2019-11-04 12:22:02 +0100 | [diff] [blame] | 2316 | /* |
| 2317 | * These are used for a global "mitigations=" cmdline option for toggling |
| 2318 | * optional CPU mitigations. |
| 2319 | */ |
| 2320 | enum cpu_mitigations { |
| 2321 | CPU_MITIGATIONS_OFF, |
| 2322 | CPU_MITIGATIONS_AUTO, |
| 2323 | CPU_MITIGATIONS_AUTO_NOSMT, |
| 2324 | }; |
| 2325 | |
| 2326 | static enum cpu_mitigations cpu_mitigations __ro_after_init = |
| 2327 | CPU_MITIGATIONS_AUTO; |
Josh Poimboeuf | edda9c3 | 2019-04-12 15:39:28 -0500 | [diff] [blame] | 2328 | |
| 2329 | static int __init mitigations_parse_cmdline(char *arg) |
| 2330 | { |
| 2331 | if (!strcmp(arg, "off")) |
| 2332 | cpu_mitigations = CPU_MITIGATIONS_OFF; |
| 2333 | else if (!strcmp(arg, "auto")) |
| 2334 | cpu_mitigations = CPU_MITIGATIONS_AUTO; |
| 2335 | else if (!strcmp(arg, "auto,nosmt")) |
| 2336 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; |
Geert Uytterhoeven | 0cbb0ae | 2019-05-16 09:09:35 +0200 | [diff] [blame] | 2337 | else |
| 2338 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", |
| 2339 | arg); |
Josh Poimboeuf | edda9c3 | 2019-04-12 15:39:28 -0500 | [diff] [blame] | 2340 | |
| 2341 | return 0; |
| 2342 | } |
| 2343 | early_param("mitigations", mitigations_parse_cmdline); |
Greg Kroah-Hartman | e0625b3 | 2019-05-14 20:43:04 +0200 | [diff] [blame] | 2344 | |
Tyler Hicks | e2bd077 | 2019-11-04 12:22:02 +0100 | [diff] [blame] | 2345 | /* mitigations=off */ |
| 2346 | bool cpu_mitigations_off(void) |
| 2347 | { |
| 2348 | return cpu_mitigations == CPU_MITIGATIONS_OFF; |
| 2349 | } |
| 2350 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); |
| 2351 | |
| 2352 | /* mitigations=auto,nosmt */ |
| 2353 | bool cpu_mitigations_auto_nosmt(void) |
| 2354 | { |
| 2355 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; |
| 2356 | } |
| 2357 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |
Greg Kroah-Hartman | 258971b | 2019-11-16 11:05:12 +0100 | [diff] [blame] | 2358 | |
Todd Poynor | ef07e9e4 | 2011-06-15 17:21:57 -0700 | [diff] [blame] | 2359 | static ATOMIC_NOTIFIER_HEAD(idle_notifier); |
| 2360 | |
| 2361 | void idle_notifier_register(struct notifier_block *n) |
| 2362 | { |
| 2363 | atomic_notifier_chain_register(&idle_notifier, n); |
| 2364 | } |
| 2365 | EXPORT_SYMBOL_GPL(idle_notifier_register); |
| 2366 | |
| 2367 | void idle_notifier_unregister(struct notifier_block *n) |
| 2368 | { |
| 2369 | atomic_notifier_chain_unregister(&idle_notifier, n); |
| 2370 | } |
| 2371 | EXPORT_SYMBOL_GPL(idle_notifier_unregister); |
| 2372 | |
| 2373 | void idle_notifier_call_chain(unsigned long val) |
| 2374 | { |
| 2375 | atomic_notifier_call_chain(&idle_notifier, val, NULL); |
| 2376 | } |
| 2377 | EXPORT_SYMBOL_GPL(idle_notifier_call_chain); |