Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
3f07c014 | 10 | #include <linux/sched/signal.h> |
ef8bd77f | 11 | #include <linux/sched/hotplug.h> |
9ca12ac0 | 12 | #include <linux/sched/isolation.h> |
29930025 | 13 | #include <linux/sched/task.h> |
a74cfffb | 14 | #include <linux/sched/smt.h> |
1da177e4 LT |
15 | #include <linux/unistd.h> |
16 | #include <linux/cpu.h> | |
cb79295e AV |
17 | #include <linux/oom.h> |
18 | #include <linux/rcupdate.h> | |
9984de1a | 19 | #include <linux/export.h> |
e4cc2f87 | 20 | #include <linux/bug.h> |
1da177e4 LT |
21 | #include <linux/kthread.h> |
22 | #include <linux/stop_machine.h> | |
81615b62 | 23 | #include <linux/mutex.h> |
5a0e3ad6 | 24 | #include <linux/gfp.h> |
79cfbdfa | 25 | #include <linux/suspend.h> |
a19423b9 | 26 | #include <linux/lockdep.h> |
345527b1 | 27 | #include <linux/tick.h> |
a8994181 | 28 | #include <linux/irq.h> |
941154bd | 29 | #include <linux/nmi.h> |
4cb28ced | 30 | #include <linux/smpboot.h> |
e6d4989a | 31 | #include <linux/relay.h> |
6731d4f1 | 32 | #include <linux/slab.h> |
fc8dffd3 | 33 | #include <linux/percpu-rwsem.h> |
cff7d378 | 34 | |
bb3632c6 | 35 | #include <trace/events/power.h> |
cff7d378 TG |
36 | #define CREATE_TRACE_POINTS |
37 | #include <trace/events/cpuhp.h> | |
1da177e4 | 38 | |
38498a67 TG |
39 | #include "smpboot.h" |
40 | ||
cff7d378 TG |
41 | /** |
42 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
43 | * @state: The current cpu state | |
44 | * @target: The target state | |
4cb28ced TG |
45 | * @thread: Pointer to the hotplug thread |
46 | * @should_run: Thread should execute | |
3b9d6da6 | 47 | * @rollback: Perform a rollback |
a724632c TG |
48 | * @single: Single callback invocation |
49 | * @bringup: Single callback bringup or teardown selector | |
50 | * @cb_state: The state for a single callback (install/uninstall) | |
4cb28ced | 51 | * @result: Result of the operation |
5ebe7742 PZ |
52 | * @done_up: Signal completion to the issuer of the task for cpu-up |
53 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
54 | */ |
55 | struct cpuhp_cpu_state { | |
56 | enum cpuhp_state state; | |
57 | enum cpuhp_state target; | |
1db49484 | 58 | enum cpuhp_state fail; |
4cb28ced TG |
59 | #ifdef CONFIG_SMP |
60 | struct task_struct *thread; | |
61 | bool should_run; | |
3b9d6da6 | 62 | bool rollback; |
a724632c TG |
63 | bool single; |
64 | bool bringup; | |
cf392d10 | 65 | struct hlist_node *node; |
4dddfb5f | 66 | struct hlist_node *last; |
4cb28ced | 67 | enum cpuhp_state cb_state; |
4cb28ced | 68 | int result; |
5ebe7742 PZ |
69 | struct completion done_up; |
70 | struct completion done_down; | |
4cb28ced | 71 | #endif |
cff7d378 TG |
72 | }; |
73 | ||
1db49484 PZ |
74 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
75 | .fail = CPUHP_INVALID, | |
76 | }; | |
cff7d378 | 77 | |
e797bda3 TG |
78 | #ifdef CONFIG_SMP |
79 | cpumask_t cpus_booted_once_mask; | |
80 | #endif | |
81 | ||
49dfe2a6 | 82 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
83 | static struct lockdep_map cpuhp_state_up_map = |
84 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
85 | static struct lockdep_map cpuhp_state_down_map = | |
86 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
87 | ||
88 | ||
76dc6c09 | 89 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
90 | { |
91 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
92 | } | |
93 | ||
76dc6c09 | 94 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
95 | { |
96 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
97 | } | |
98 | #else | |
99 | ||
76dc6c09 MM |
100 | static inline void cpuhp_lock_acquire(bool bringup) { } |
101 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 102 | |
49dfe2a6 TG |
103 | #endif |
104 | ||
cff7d378 TG |
105 | /** |
106 | * cpuhp_step - Hotplug state machine step | |
107 | * @name: Name of the step | |
108 | * @startup: Startup function of the step | |
109 | * @teardown: Teardown function of the step | |
757c989b | 110 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
111 | */ |
112 | struct cpuhp_step { | |
cf392d10 TG |
113 | const char *name; |
114 | union { | |
3c1627e9 TG |
115 | int (*single)(unsigned int cpu); |
116 | int (*multi)(unsigned int cpu, | |
117 | struct hlist_node *node); | |
118 | } startup; | |
cf392d10 | 119 | union { |
3c1627e9 TG |
120 | int (*single)(unsigned int cpu); |
121 | int (*multi)(unsigned int cpu, | |
122 | struct hlist_node *node); | |
123 | } teardown; | |
cf392d10 | 124 | struct hlist_head list; |
cf392d10 TG |
125 | bool cant_stop; |
126 | bool multi_instance; | |
cff7d378 TG |
127 | }; |
128 | ||
98f8cdce | 129 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 130 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 131 | |
a724632c TG |
132 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
133 | { | |
17a2f1ce | 134 | return cpuhp_hp_states + state; |
a724632c TG |
135 | } |
136 | ||
cff7d378 TG |
137 | /** |
138 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
139 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 140 | * @state: The state to do callbacks for |
a724632c | 141 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
142 | * @node: For multi-instance, do a single entry callback for install/remove |
143 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 144 | * |
cf392d10 | 145 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 146 | */ |
a724632c | 147 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
148 | bool bringup, struct hlist_node *node, |
149 | struct hlist_node **lastp) | |
cff7d378 TG |
150 | { |
151 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 152 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
153 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
154 | int (*cb)(unsigned int cpu); | |
155 | int ret, cnt; | |
156 | ||
1db49484 PZ |
157 | if (st->fail == state) { |
158 | st->fail = CPUHP_INVALID; | |
159 | ||
160 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
161 | return 0; | |
162 | ||
163 | return -EAGAIN; | |
164 | } | |
165 | ||
cf392d10 | 166 | if (!step->multi_instance) { |
96abb968 | 167 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 168 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
169 | if (!cb) |
170 | return 0; | |
a724632c | 171 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 172 | ret = cb(cpu); |
a724632c | 173 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
174 | return ret; |
175 | } | |
3c1627e9 | 176 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
177 | if (!cbm) |
178 | return 0; | |
179 | ||
180 | /* Single invocation for instance add/remove */ | |
181 | if (node) { | |
96abb968 | 182 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
183 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
184 | ret = cbm(cpu, node); | |
185 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
186 | return ret; | |
187 | } | |
188 | ||
189 | /* State transition. Invoke on all instances */ | |
190 | cnt = 0; | |
191 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
192 | if (lastp && node == *lastp) |
193 | break; | |
194 | ||
cf392d10 TG |
195 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
196 | ret = cbm(cpu, node); | |
197 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
198 | if (ret) { |
199 | if (!lastp) | |
200 | goto err; | |
201 | ||
202 | *lastp = node; | |
203 | return ret; | |
204 | } | |
cf392d10 TG |
205 | cnt++; |
206 | } | |
96abb968 PZ |
207 | if (lastp) |
208 | *lastp = NULL; | |
cf392d10 TG |
209 | return 0; |
210 | err: | |
211 | /* Rollback the instances if one failed */ | |
3c1627e9 | 212 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
213 | if (!cbm) |
214 | return ret; | |
215 | ||
216 | hlist_for_each(node, &step->list) { | |
217 | if (!cnt--) | |
218 | break; | |
724a8688 PZ |
219 | |
220 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
221 | ret = cbm(cpu, node); | |
222 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
223 | /* | |
224 | * Rollback must not fail, | |
225 | */ | |
226 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
227 | } |
228 | return ret; | |
229 | } | |
230 | ||
98a79d6a | 231 | #ifdef CONFIG_SMP |
fcb3029a AB |
232 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
233 | { | |
234 | /* | |
235 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
236 | * purposes as that state is handled explicitly in cpu_down. | |
237 | */ | |
238 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
239 | } | |
240 | ||
5ebe7742 PZ |
241 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
242 | { | |
243 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
244 | wait_for_completion(done); | |
245 | } | |
246 | ||
247 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
248 | { | |
249 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
250 | complete(done); | |
251 | } | |
252 | ||
253 | /* | |
254 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
255 | */ | |
256 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
257 | { | |
258 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
259 | } | |
260 | ||
b3199c02 | 261 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 262 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
263 | bool cpuhp_tasks_frozen; |
264 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 265 | |
79a6cdeb | 266 | /* |
93ae4f97 SB |
267 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
268 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
269 | */ |
270 | void cpu_maps_update_begin(void) | |
271 | { | |
272 | mutex_lock(&cpu_add_remove_lock); | |
273 | } | |
274 | ||
275 | void cpu_maps_update_done(void) | |
276 | { | |
277 | mutex_unlock(&cpu_add_remove_lock); | |
278 | } | |
1da177e4 | 279 | |
fc8dffd3 TG |
280 | /* |
281 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
282 | * Should always be manipulated under cpu_add_remove_lock |
283 | */ | |
284 | static int cpu_hotplug_disabled; | |
285 | ||
79a6cdeb LJ |
286 | #ifdef CONFIG_HOTPLUG_CPU |
287 | ||
fc8dffd3 | 288 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 289 | |
8f553c49 | 290 | void cpus_read_lock(void) |
a9d9baa1 | 291 | { |
fc8dffd3 | 292 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 293 | } |
8f553c49 | 294 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 295 | |
6f4ceee9 WL |
296 | int cpus_read_trylock(void) |
297 | { | |
298 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
299 | } | |
300 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
301 | ||
8f553c49 | 302 | void cpus_read_unlock(void) |
a9d9baa1 | 303 | { |
fc8dffd3 | 304 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 305 | } |
8f553c49 | 306 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 307 | |
8f553c49 | 308 | void cpus_write_lock(void) |
d221938c | 309 | { |
fc8dffd3 | 310 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 311 | } |
87af9e7f | 312 | |
8f553c49 | 313 | void cpus_write_unlock(void) |
d221938c | 314 | { |
fc8dffd3 | 315 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
316 | } |
317 | ||
fc8dffd3 | 318 | void lockdep_assert_cpus_held(void) |
d221938c | 319 | { |
ce48c457 VS |
320 | /* |
321 | * We can't have hotplug operations before userspace starts running, | |
322 | * and some init codepaths will knowingly not take the hotplug lock. | |
323 | * This is all valid, so mute lockdep until it makes sense to report | |
324 | * unheld locks. | |
325 | */ | |
326 | if (system_state < SYSTEM_RUNNING) | |
327 | return; | |
328 | ||
fc8dffd3 | 329 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 330 | } |
79a6cdeb | 331 | |
cb92173d PZ |
332 | static void lockdep_acquire_cpus_lock(void) |
333 | { | |
334 | rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_); | |
335 | } | |
336 | ||
337 | static void lockdep_release_cpus_lock(void) | |
338 | { | |
5facae4f | 339 | rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, _THIS_IP_); |
cb92173d PZ |
340 | } |
341 | ||
16e53dbf SB |
342 | /* |
343 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
344 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
345 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
346 | * hotplug path before performing hotplug operations. So acquiring that lock | |
347 | * guarantees mutual exclusion from any currently running hotplug operations. | |
348 | */ | |
349 | void cpu_hotplug_disable(void) | |
350 | { | |
351 | cpu_maps_update_begin(); | |
89af7ba5 | 352 | cpu_hotplug_disabled++; |
16e53dbf SB |
353 | cpu_maps_update_done(); |
354 | } | |
32145c46 | 355 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 356 | |
01b41159 LW |
357 | static void __cpu_hotplug_enable(void) |
358 | { | |
359 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
360 | return; | |
361 | cpu_hotplug_disabled--; | |
362 | } | |
363 | ||
16e53dbf SB |
364 | void cpu_hotplug_enable(void) |
365 | { | |
366 | cpu_maps_update_begin(); | |
01b41159 | 367 | __cpu_hotplug_enable(); |
16e53dbf SB |
368 | cpu_maps_update_done(); |
369 | } | |
32145c46 | 370 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
371 | |
372 | #else | |
373 | ||
374 | static void lockdep_acquire_cpus_lock(void) | |
375 | { | |
376 | } | |
377 | ||
378 | static void lockdep_release_cpus_lock(void) | |
379 | { | |
380 | } | |
381 | ||
b9d10be7 | 382 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 383 | |
a74cfffb TG |
384 | /* |
385 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
386 | * should override this. | |
387 | */ | |
388 | void __weak arch_smt_update(void) { } | |
389 | ||
0cc3cd21 TG |
390 | #ifdef CONFIG_HOTPLUG_SMT |
391 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 392 | |
8e1b706b | 393 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 394 | { |
e1572f1d | 395 | if (!cpu_smt_possible()) |
8e1b706b JK |
396 | return; |
397 | ||
398 | if (force) { | |
0cc3cd21 TG |
399 | pr_info("SMT: Force disabled\n"); |
400 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 401 | } else { |
d0e7d144 | 402 | pr_info("SMT: disabled\n"); |
8e1b706b | 403 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 404 | } |
8e1b706b JK |
405 | } |
406 | ||
fee0aede TG |
407 | /* |
408 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 409 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
410 | */ |
411 | void __init cpu_smt_check_topology(void) | |
412 | { | |
b284909a | 413 | if (!topology_smt_supported()) |
bc2d8d26 TG |
414 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
415 | } | |
416 | ||
8e1b706b JK |
417 | static int __init smt_cmdline_disable(char *str) |
418 | { | |
419 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
420 | return 0; |
421 | } | |
422 | early_param("nosmt", smt_cmdline_disable); | |
423 | ||
424 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
425 | { | |
b284909a | 426 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
427 | return true; |
428 | ||
b284909a | 429 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
430 | return true; |
431 | ||
432 | /* | |
433 | * On x86 it's required to boot all logical CPUs at least once so | |
434 | * that the init code can get a chance to set CR4.MCE on each | |
435 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any | |
436 | * core will shutdown the machine. | |
437 | */ | |
e797bda3 | 438 | return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); |
0cc3cd21 | 439 | } |
e1572f1d VK |
440 | |
441 | /* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ | |
442 | bool cpu_smt_possible(void) | |
443 | { | |
444 | return cpu_smt_control != CPU_SMT_FORCE_DISABLED && | |
445 | cpu_smt_control != CPU_SMT_NOT_SUPPORTED; | |
446 | } | |
447 | EXPORT_SYMBOL_GPL(cpu_smt_possible); | |
0cc3cd21 TG |
448 | #else |
449 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
450 | #endif | |
451 | ||
4dddfb5f PZ |
452 | static inline enum cpuhp_state |
453 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
454 | { | |
455 | enum cpuhp_state prev_state = st->state; | |
456 | ||
457 | st->rollback = false; | |
458 | st->last = NULL; | |
459 | ||
460 | st->target = target; | |
461 | st->single = false; | |
462 | st->bringup = st->state < target; | |
463 | ||
464 | return prev_state; | |
465 | } | |
466 | ||
467 | static inline void | |
468 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
469 | { | |
470 | st->rollback = true; | |
471 | ||
472 | /* | |
473 | * If we have st->last we need to undo partial multi_instance of this | |
474 | * state first. Otherwise start undo at the previous state. | |
475 | */ | |
476 | if (!st->last) { | |
477 | if (st->bringup) | |
478 | st->state--; | |
479 | else | |
480 | st->state++; | |
481 | } | |
482 | ||
483 | st->target = prev_state; | |
484 | st->bringup = !st->bringup; | |
485 | } | |
486 | ||
487 | /* Regular hotplug invocation of the AP hotplug thread */ | |
488 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
489 | { | |
490 | if (!st->single && st->state == st->target) | |
491 | return; | |
492 | ||
493 | st->result = 0; | |
494 | /* | |
495 | * Make sure the above stores are visible before should_run becomes | |
496 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
497 | */ | |
498 | smp_mb(); | |
499 | st->should_run = true; | |
500 | wake_up_process(st->thread); | |
5ebe7742 | 501 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
502 | } |
503 | ||
504 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
505 | { | |
506 | enum cpuhp_state prev_state; | |
507 | int ret; | |
508 | ||
509 | prev_state = cpuhp_set_state(st, target); | |
510 | __cpuhp_kick_ap(st); | |
511 | if ((ret = st->result)) { | |
512 | cpuhp_reset_state(st, prev_state); | |
513 | __cpuhp_kick_ap(st); | |
514 | } | |
515 | ||
516 | return ret; | |
517 | } | |
9cd4f1a4 | 518 | |
8df3e07e TG |
519 | static int bringup_wait_for_ap(unsigned int cpu) |
520 | { | |
521 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
522 | ||
9cd4f1a4 | 523 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 524 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
525 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
526 | return -ECANCELED; | |
9cd4f1a4 | 527 | |
45178ac0 | 528 | /* Unpark the hotplug thread of the target cpu */ |
9cd4f1a4 TG |
529 | kthread_unpark(st->thread); |
530 | ||
0cc3cd21 TG |
531 | /* |
532 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
533 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 534 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
535 | * cpu_smt_allowed() check will now return false if this is not the |
536 | * primary sibling. | |
537 | */ | |
538 | if (!cpu_smt_allowed(cpu)) | |
539 | return -ECANCELED; | |
540 | ||
4dddfb5f PZ |
541 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
542 | return 0; | |
543 | ||
544 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
545 | } |
546 | ||
ba997462 TG |
547 | static int bringup_cpu(unsigned int cpu) |
548 | { | |
549 | struct task_struct *idle = idle_thread_get(cpu); | |
550 | int ret; | |
551 | ||
aa877175 BO |
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 | ||
ba997462 TG |
559 | /* Arch-specific enabling code. */ |
560 | ret = __cpu_up(cpu, idle); | |
aa877175 | 561 | irq_unlock_sparse(); |
530e9b76 | 562 | if (ret) |
ba997462 | 563 | return ret; |
9cd4f1a4 | 564 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
565 | } |
566 | ||
2e1a3483 TG |
567 | /* |
568 | * Hotplug state machine related functions | |
569 | */ | |
2e1a3483 | 570 | |
a724632c | 571 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 | 572 | { |
6fb86d97 MO |
573 | for (st->state--; st->state > st->target; st->state--) |
574 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
2e1a3483 TG |
575 | } |
576 | ||
206b9235 TG |
577 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
578 | { | |
579 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
580 | return true; | |
581 | /* | |
582 | * When CPU hotplug is disabled, then taking the CPU down is not | |
583 | * possible because takedown_cpu() and the architecture and | |
584 | * subsystem specific mechanisms are not available. So the CPU | |
585 | * which would be completely unplugged again needs to stay around | |
586 | * in the current state. | |
587 | */ | |
588 | return st->state <= CPUHP_BRINGUP_CPU; | |
589 | } | |
590 | ||
2e1a3483 | 591 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 592 | enum cpuhp_state target) |
2e1a3483 TG |
593 | { |
594 | enum cpuhp_state prev_state = st->state; | |
595 | int ret = 0; | |
596 | ||
597 | while (st->state < target) { | |
2e1a3483 | 598 | st->state++; |
96abb968 | 599 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 | 600 | if (ret) { |
206b9235 TG |
601 | if (can_rollback_cpu(st)) { |
602 | st->target = prev_state; | |
603 | undo_cpu_up(cpu, st); | |
604 | } | |
2e1a3483 TG |
605 | break; |
606 | } | |
607 | } | |
608 | return ret; | |
609 | } | |
610 | ||
4cb28ced TG |
611 | /* |
612 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
613 | */ | |
614 | static void cpuhp_create(unsigned int cpu) | |
615 | { | |
616 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
617 | ||
5ebe7742 PZ |
618 | init_completion(&st->done_up); |
619 | init_completion(&st->done_down); | |
4cb28ced TG |
620 | } |
621 | ||
622 | static int cpuhp_should_run(unsigned int cpu) | |
623 | { | |
624 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
625 | ||
626 | return st->should_run; | |
627 | } | |
628 | ||
4cb28ced TG |
629 | /* |
630 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
631 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
632 | * |
633 | * Each invocation of this function by the smpboot thread does a single AP | |
634 | * state callback. | |
635 | * | |
636 | * It has 3 modes of operation: | |
637 | * - single: runs st->cb_state | |
638 | * - up: runs ++st->state, while st->state < st->target | |
639 | * - down: runs st->state--, while st->state > st->target | |
640 | * | |
641 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
642 | */ |
643 | static void cpuhp_thread_fun(unsigned int cpu) | |
644 | { | |
645 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
646 | bool bringup = st->bringup; |
647 | enum cpuhp_state state; | |
4cb28ced | 648 | |
f8b7530a NU |
649 | if (WARN_ON_ONCE(!st->should_run)) |
650 | return; | |
651 | ||
4cb28ced | 652 | /* |
4dddfb5f PZ |
653 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
654 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
655 | */ |
656 | smp_mb(); | |
4cb28ced | 657 | |
cb92173d PZ |
658 | /* |
659 | * The BP holds the hotplug lock, but we're now running on the AP, | |
660 | * ensure that anybody asserting the lock is held, will actually find | |
661 | * it so. | |
662 | */ | |
663 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 664 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 665 | |
a724632c | 666 | if (st->single) { |
4dddfb5f PZ |
667 | state = st->cb_state; |
668 | st->should_run = false; | |
669 | } else { | |
670 | if (bringup) { | |
671 | st->state++; | |
672 | state = st->state; | |
673 | st->should_run = (st->state < st->target); | |
674 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 675 | } else { |
4dddfb5f PZ |
676 | state = st->state; |
677 | st->state--; | |
678 | st->should_run = (st->state > st->target); | |
679 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 680 | } |
4dddfb5f PZ |
681 | } |
682 | ||
683 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
684 | ||
4dddfb5f PZ |
685 | if (cpuhp_is_atomic_state(state)) { |
686 | local_irq_disable(); | |
687 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
688 | local_irq_enable(); | |
3b9d6da6 | 689 | |
4dddfb5f PZ |
690 | /* |
691 | * STARTING/DYING must not fail! | |
692 | */ | |
693 | WARN_ON_ONCE(st->result); | |
4cb28ced | 694 | } else { |
4dddfb5f PZ |
695 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
696 | } | |
697 | ||
698 | if (st->result) { | |
699 | /* | |
700 | * If we fail on a rollback, we're up a creek without no | |
701 | * paddle, no way forward, no way back. We loose, thanks for | |
702 | * playing. | |
703 | */ | |
704 | WARN_ON_ONCE(st->rollback); | |
705 | st->should_run = false; | |
4cb28ced | 706 | } |
4dddfb5f | 707 | |
5f4b55e1 | 708 | cpuhp_lock_release(bringup); |
cb92173d | 709 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
710 | |
711 | if (!st->should_run) | |
5ebe7742 | 712 | complete_ap_thread(st, bringup); |
4cb28ced TG |
713 | } |
714 | ||
715 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 716 | static int |
cf392d10 TG |
717 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
718 | struct hlist_node *node) | |
4cb28ced TG |
719 | { |
720 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 721 | int ret; |
4cb28ced TG |
722 | |
723 | if (!cpu_online(cpu)) | |
724 | return 0; | |
725 | ||
5f4b55e1 PZ |
726 | cpuhp_lock_acquire(false); |
727 | cpuhp_lock_release(false); | |
728 | ||
729 | cpuhp_lock_acquire(true); | |
730 | cpuhp_lock_release(true); | |
49dfe2a6 | 731 | |
6a4e2451 TG |
732 | /* |
733 | * If we are up and running, use the hotplug thread. For early calls | |
734 | * we invoke the thread function directly. | |
735 | */ | |
736 | if (!st->thread) | |
96abb968 | 737 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 738 | |
4dddfb5f PZ |
739 | st->rollback = false; |
740 | st->last = NULL; | |
741 | ||
742 | st->node = node; | |
743 | st->bringup = bringup; | |
4cb28ced | 744 | st->cb_state = state; |
a724632c | 745 | st->single = true; |
a724632c | 746 | |
4dddfb5f | 747 | __cpuhp_kick_ap(st); |
4cb28ced | 748 | |
4cb28ced | 749 | /* |
4dddfb5f | 750 | * If we failed and did a partial, do a rollback. |
4cb28ced | 751 | */ |
4dddfb5f PZ |
752 | if ((ret = st->result) && st->last) { |
753 | st->rollback = true; | |
754 | st->bringup = !bringup; | |
755 | ||
756 | __cpuhp_kick_ap(st); | |
757 | } | |
758 | ||
1f7c70d6 TG |
759 | /* |
760 | * Clean up the leftovers so the next hotplug operation wont use stale | |
761 | * data. | |
762 | */ | |
763 | st->node = st->last = NULL; | |
4dddfb5f | 764 | return ret; |
1cf4f629 TG |
765 | } |
766 | ||
767 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
768 | { | |
769 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
770 | enum cpuhp_state prev_state = st->state; |
771 | int ret; | |
1cf4f629 | 772 | |
5f4b55e1 PZ |
773 | cpuhp_lock_acquire(false); |
774 | cpuhp_lock_release(false); | |
775 | ||
776 | cpuhp_lock_acquire(true); | |
777 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
778 | |
779 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
780 | ret = cpuhp_kick_ap(st, st->target); | |
781 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
782 | ||
783 | return ret; | |
4cb28ced TG |
784 | } |
785 | ||
786 | static struct smp_hotplug_thread cpuhp_threads = { | |
787 | .store = &cpuhp_state.thread, | |
788 | .create = &cpuhp_create, | |
789 | .thread_should_run = cpuhp_should_run, | |
790 | .thread_fn = cpuhp_thread_fun, | |
791 | .thread_comm = "cpuhp/%u", | |
792 | .selfparking = true, | |
793 | }; | |
794 | ||
795 | void __init cpuhp_threads_init(void) | |
796 | { | |
797 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
798 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
799 | } | |
800 | ||
777c6e0d | 801 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
802 | /** |
803 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
804 | * @cpu: a CPU id | |
805 | * | |
806 | * This function walks all processes, finds a valid mm struct for each one and | |
807 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
808 | * trivial, there are various non-obvious corner cases, which this function | |
809 | * tries to solve in a safe manner. | |
810 | * | |
811 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
812 | * be called only for an already offlined CPU. | |
813 | */ | |
cb79295e AV |
814 | void clear_tasks_mm_cpumask(int cpu) |
815 | { | |
816 | struct task_struct *p; | |
817 | ||
818 | /* | |
819 | * This function is called after the cpu is taken down and marked | |
820 | * offline, so its not like new tasks will ever get this cpu set in | |
821 | * their mm mask. -- Peter Zijlstra | |
822 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
823 | * full-fledged tasklist_lock. | |
824 | */ | |
e4cc2f87 | 825 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
826 | rcu_read_lock(); |
827 | for_each_process(p) { | |
828 | struct task_struct *t; | |
829 | ||
e4cc2f87 AV |
830 | /* |
831 | * Main thread might exit, but other threads may still have | |
832 | * a valid mm. Find one. | |
833 | */ | |
cb79295e AV |
834 | t = find_lock_task_mm(p); |
835 | if (!t) | |
836 | continue; | |
837 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
838 | task_unlock(t); | |
839 | } | |
840 | rcu_read_unlock(); | |
841 | } | |
842 | ||
1da177e4 | 843 | /* Take this CPU down. */ |
71cf5aee | 844 | static int take_cpu_down(void *_param) |
1da177e4 | 845 | { |
4baa0afc TG |
846 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
847 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 848 | int err, cpu = smp_processor_id(); |
724a8688 | 849 | int ret; |
1da177e4 | 850 | |
1da177e4 LT |
851 | /* Ensure this CPU doesn't handle any more interrupts. */ |
852 | err = __cpu_disable(); | |
853 | if (err < 0) | |
f3705136 | 854 | return err; |
1da177e4 | 855 | |
a724632c TG |
856 | /* |
857 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
858 | * do this step again. | |
859 | */ | |
860 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
861 | st->state--; | |
4baa0afc | 862 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
863 | for (; st->state > target; st->state--) { |
864 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
865 | /* | |
866 | * DYING must not fail! | |
867 | */ | |
868 | WARN_ON_ONCE(ret); | |
869 | } | |
4baa0afc | 870 | |
52c063d1 TG |
871 | /* Give up timekeeping duties */ |
872 | tick_handover_do_timer(); | |
1b72d432 TG |
873 | /* Remove CPU from timer broadcasting */ |
874 | tick_offline_cpu(cpu); | |
14e568e7 | 875 | /* Park the stopper thread */ |
090e77c3 | 876 | stop_machine_park(cpu); |
f3705136 | 877 | return 0; |
1da177e4 LT |
878 | } |
879 | ||
98458172 | 880 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 881 | { |
e69aab13 | 882 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 883 | int err; |
1da177e4 | 884 | |
2a58c527 | 885 | /* Park the smpboot threads */ |
1cf4f629 TG |
886 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
887 | ||
6acce3ef | 888 | /* |
a8994181 TG |
889 | * Prevent irq alloc/free while the dying cpu reorganizes the |
890 | * interrupt affinities. | |
6acce3ef | 891 | */ |
a8994181 | 892 | irq_lock_sparse(); |
6acce3ef | 893 | |
a8994181 TG |
894 | /* |
895 | * So now all preempt/rcu users must observe !cpu_active(). | |
896 | */ | |
210e2133 | 897 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 898 | if (err) { |
3b9d6da6 | 899 | /* CPU refused to die */ |
a8994181 | 900 | irq_unlock_sparse(); |
3b9d6da6 SAS |
901 | /* Unpark the hotplug thread so we can rollback there */ |
902 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 903 | return err; |
8fa1d7d3 | 904 | } |
04321587 | 905 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 906 | |
48c5ccae | 907 | /* |
5b1ead68 BJ |
908 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
909 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 910 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
911 | * |
912 | * Wait for the stop thread to go away. | |
48c5ccae | 913 | */ |
5ebe7742 | 914 | wait_for_ap_thread(st, false); |
e69aab13 | 915 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 916 | |
a8994181 TG |
917 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
918 | irq_unlock_sparse(); | |
919 | ||
345527b1 | 920 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
921 | /* This actually kills the CPU. */ |
922 | __cpu_die(cpu); | |
923 | ||
a49b116d | 924 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 925 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
926 | return 0; |
927 | } | |
1da177e4 | 928 | |
71f87b2f TG |
929 | static void cpuhp_complete_idle_dead(void *arg) |
930 | { | |
931 | struct cpuhp_cpu_state *st = arg; | |
932 | ||
5ebe7742 | 933 | complete_ap_thread(st, false); |
71f87b2f TG |
934 | } |
935 | ||
e69aab13 TG |
936 | void cpuhp_report_idle_dead(void) |
937 | { | |
938 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
939 | ||
940 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 941 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
942 | st->state = CPUHP_AP_IDLE_DEAD; |
943 | /* | |
944 | * We cannot call complete after rcu_report_dead() so we delegate it | |
945 | * to an online cpu. | |
946 | */ | |
947 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
948 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
949 | } |
950 | ||
4dddfb5f PZ |
951 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
952 | { | |
6fb86d97 MO |
953 | for (st->state++; st->state < st->target; st->state++) |
954 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
4dddfb5f PZ |
955 | } |
956 | ||
957 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
958 | enum cpuhp_state target) | |
959 | { | |
960 | enum cpuhp_state prev_state = st->state; | |
961 | int ret = 0; | |
962 | ||
963 | for (; st->state > target; st->state--) { | |
964 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
965 | if (ret) { | |
966 | st->target = prev_state; | |
69fa6eb7 TG |
967 | if (st->state < prev_state) |
968 | undo_cpu_down(cpu, st); | |
4dddfb5f PZ |
969 | break; |
970 | } | |
971 | } | |
972 | return ret; | |
973 | } | |
cff7d378 | 974 | |
98458172 | 975 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
976 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
977 | enum cpuhp_state target) | |
98458172 | 978 | { |
cff7d378 TG |
979 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
980 | int prev_state, ret = 0; | |
98458172 TG |
981 | |
982 | if (num_online_cpus() == 1) | |
983 | return -EBUSY; | |
984 | ||
757c989b | 985 | if (!cpu_present(cpu)) |
98458172 TG |
986 | return -EINVAL; |
987 | ||
8f553c49 | 988 | cpus_write_lock(); |
98458172 TG |
989 | |
990 | cpuhp_tasks_frozen = tasks_frozen; | |
991 | ||
4dddfb5f | 992 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
993 | /* |
994 | * If the current CPU state is in the range of the AP hotplug thread, | |
995 | * then we need to kick the thread. | |
996 | */ | |
8df3e07e | 997 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 998 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
999 | ret = cpuhp_kick_ap_work(cpu); |
1000 | /* | |
1001 | * The AP side has done the error rollback already. Just | |
1002 | * return the error code.. | |
1003 | */ | |
1004 | if (ret) | |
1005 | goto out; | |
1006 | ||
1007 | /* | |
1008 | * We might have stopped still in the range of the AP hotplug | |
1009 | * thread. Nothing to do anymore. | |
1010 | */ | |
8df3e07e | 1011 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1012 | goto out; |
4dddfb5f PZ |
1013 | |
1014 | st->target = target; | |
1cf4f629 TG |
1015 | } |
1016 | /* | |
8df3e07e | 1017 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1018 | * to do the further cleanups. |
1019 | */ | |
a724632c | 1020 | ret = cpuhp_down_callbacks(cpu, st, target); |
69fa6eb7 | 1021 | if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
1022 | cpuhp_reset_state(st, prev_state); |
1023 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 1024 | } |
98458172 | 1025 | |
1cf4f629 | 1026 | out: |
8f553c49 | 1027 | cpus_write_unlock(); |
941154bd TG |
1028 | /* |
1029 | * Do post unplug cleanup. This is still protected against | |
1030 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1031 | */ | |
1032 | lockup_detector_cleanup(); | |
a74cfffb | 1033 | arch_smt_update(); |
cff7d378 | 1034 | return ret; |
e3920fb4 RW |
1035 | } |
1036 | ||
cc1fe215 TG |
1037 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1038 | { | |
1039 | if (cpu_hotplug_disabled) | |
1040 | return -EBUSY; | |
1041 | return _cpu_down(cpu, 0, target); | |
1042 | } | |
1043 | ||
af1f4045 | 1044 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1045 | { |
9ea09af3 | 1046 | int err; |
e3920fb4 | 1047 | |
d221938c | 1048 | cpu_maps_update_begin(); |
cc1fe215 | 1049 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1050 | cpu_maps_update_done(); |
1da177e4 LT |
1051 | return err; |
1052 | } | |
4dddfb5f | 1053 | |
af1f4045 TG |
1054 | int cpu_down(unsigned int cpu) |
1055 | { | |
1056 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1057 | } | |
b62b8ef9 | 1058 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f PZ |
1059 | |
1060 | #else | |
1061 | #define takedown_cpu NULL | |
1da177e4 LT |
1062 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1063 | ||
4baa0afc | 1064 | /** |
ee1e714b | 1065 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1066 | * @cpu: cpu that just started |
1067 | * | |
4baa0afc TG |
1068 | * It must be called by the arch code on the new cpu, before the new cpu |
1069 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1070 | */ | |
1071 | void notify_cpu_starting(unsigned int cpu) | |
1072 | { | |
1073 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1074 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1075 | int ret; |
4baa0afc | 1076 | |
0c6d4576 | 1077 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1078 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
4baa0afc | 1079 | while (st->state < target) { |
4baa0afc | 1080 | st->state++; |
724a8688 PZ |
1081 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1082 | /* | |
1083 | * STARTING must not fail! | |
1084 | */ | |
1085 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1086 | } |
1087 | } | |
1088 | ||
949338e3 | 1089 | /* |
9cd4f1a4 | 1090 | * Called from the idle task. Wake up the controlling task which brings the |
45178ac0 PZ |
1091 | * hotplug thread of the upcoming CPU up and then delegates the rest of the |
1092 | * online bringup to the hotplug thread. | |
949338e3 | 1093 | */ |
8df3e07e | 1094 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1095 | { |
8df3e07e | 1096 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1097 | |
1098 | /* Happens for the boot cpu */ | |
1099 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1100 | return; | |
1101 | ||
45178ac0 PZ |
1102 | /* |
1103 | * Unpart the stopper thread before we start the idle loop (and start | |
1104 | * scheduling); this ensures the stopper task is always available. | |
1105 | */ | |
1106 | stop_machine_unpark(smp_processor_id()); | |
1107 | ||
8df3e07e | 1108 | st->state = CPUHP_AP_ONLINE_IDLE; |
5ebe7742 | 1109 | complete_ap_thread(st, true); |
949338e3 TG |
1110 | } |
1111 | ||
e3920fb4 | 1112 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1113 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1114 | { |
cff7d378 | 1115 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1116 | struct task_struct *idle; |
2e1a3483 | 1117 | int ret = 0; |
1da177e4 | 1118 | |
8f553c49 | 1119 | cpus_write_lock(); |
38498a67 | 1120 | |
757c989b | 1121 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1122 | ret = -EINVAL; |
1123 | goto out; | |
1124 | } | |
1125 | ||
757c989b TG |
1126 | /* |
1127 | * The caller of do_cpu_up might have raced with another | |
1128 | * caller. Ignore it for now. | |
1129 | */ | |
1130 | if (st->state >= target) | |
38498a67 | 1131 | goto out; |
757c989b TG |
1132 | |
1133 | if (st->state == CPUHP_OFFLINE) { | |
1134 | /* Let it fail before we try to bring the cpu up */ | |
1135 | idle = idle_thread_get(cpu); | |
1136 | if (IS_ERR(idle)) { | |
1137 | ret = PTR_ERR(idle); | |
1138 | goto out; | |
1139 | } | |
3bb5d2ee | 1140 | } |
38498a67 | 1141 | |
ba997462 TG |
1142 | cpuhp_tasks_frozen = tasks_frozen; |
1143 | ||
4dddfb5f | 1144 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1145 | /* |
1146 | * If the current CPU state is in the range of the AP hotplug thread, | |
1147 | * then we need to kick the thread once more. | |
1148 | */ | |
8df3e07e | 1149 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1150 | ret = cpuhp_kick_ap_work(cpu); |
1151 | /* | |
1152 | * The AP side has done the error rollback already. Just | |
1153 | * return the error code.. | |
1154 | */ | |
1155 | if (ret) | |
1156 | goto out; | |
1157 | } | |
1158 | ||
1159 | /* | |
1160 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1161 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1162 | * responsible for bringing it up to the target state. |
1163 | */ | |
8df3e07e | 1164 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1165 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1166 | out: |
8f553c49 | 1167 | cpus_write_unlock(); |
a74cfffb | 1168 | arch_smt_update(); |
e3920fb4 RW |
1169 | return ret; |
1170 | } | |
1171 | ||
af1f4045 | 1172 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1173 | { |
1174 | int err = 0; | |
cf23422b | 1175 | |
e0b582ec | 1176 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1177 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1178 | cpu); | |
87d5e023 | 1179 | #if defined(CONFIG_IA64) |
84117da5 | 1180 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1181 | #endif |
1182 | return -EINVAL; | |
1183 | } | |
e3920fb4 | 1184 | |
01b0f197 TK |
1185 | err = try_online_node(cpu_to_node(cpu)); |
1186 | if (err) | |
1187 | return err; | |
cf23422b | 1188 | |
d221938c | 1189 | cpu_maps_update_begin(); |
e761b772 MK |
1190 | |
1191 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1192 | err = -EBUSY; |
e761b772 MK |
1193 | goto out; |
1194 | } | |
05736e4a TG |
1195 | if (!cpu_smt_allowed(cpu)) { |
1196 | err = -EPERM; | |
1197 | goto out; | |
1198 | } | |
e761b772 | 1199 | |
af1f4045 | 1200 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1201 | out: |
d221938c | 1202 | cpu_maps_update_done(); |
e3920fb4 RW |
1203 | return err; |
1204 | } | |
af1f4045 TG |
1205 | |
1206 | int cpu_up(unsigned int cpu) | |
1207 | { | |
1208 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1209 | } | |
a513f6ba | 1210 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1211 | |
f3de4be9 | 1212 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1213 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1214 | |
d391e552 | 1215 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1216 | { |
d391e552 | 1217 | int cpu, error = 0; |
e3920fb4 | 1218 | |
d221938c | 1219 | cpu_maps_update_begin(); |
9ca12ac0 | 1220 | if (primary == -1) { |
d391e552 | 1221 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1222 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1223 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1224 | } else { | |
1225 | if (!cpu_online(primary)) | |
1226 | primary = cpumask_first(cpu_online_mask); | |
1227 | } | |
1228 | ||
9ee349ad XF |
1229 | /* |
1230 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1231 | * with the userspace trying to use the CPU hotplug at the same time |
1232 | */ | |
e0b582ec | 1233 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1234 | |
84117da5 | 1235 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1236 | for_each_online_cpu(cpu) { |
d391e552 | 1237 | if (cpu == primary) |
e3920fb4 | 1238 | continue; |
a66d955e PK |
1239 | |
1240 | if (pm_wakeup_pending()) { | |
1241 | pr_info("Wakeup pending. Abort CPU freeze\n"); | |
1242 | error = -EBUSY; | |
1243 | break; | |
1244 | } | |
1245 | ||
bb3632c6 | 1246 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1247 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1248 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1249 | if (!error) |
e0b582ec | 1250 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1251 | else { |
84117da5 | 1252 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1253 | break; |
1254 | } | |
1255 | } | |
86886e55 | 1256 | |
89af7ba5 | 1257 | if (!error) |
e3920fb4 | 1258 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1259 | else |
84117da5 | 1260 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1261 | |
1262 | /* | |
1263 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1264 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1265 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1266 | */ | |
1267 | cpu_hotplug_disabled++; | |
1268 | ||
d221938c | 1269 | cpu_maps_update_done(); |
e3920fb4 RW |
1270 | return error; |
1271 | } | |
1272 | ||
d0af9eed SS |
1273 | void __weak arch_enable_nonboot_cpus_begin(void) |
1274 | { | |
1275 | } | |
1276 | ||
1277 | void __weak arch_enable_nonboot_cpus_end(void) | |
1278 | { | |
1279 | } | |
1280 | ||
71cf5aee | 1281 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1282 | { |
1283 | int cpu, error; | |
1284 | ||
1285 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1286 | cpu_maps_update_begin(); |
01b41159 | 1287 | __cpu_hotplug_enable(); |
e0b582ec | 1288 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1289 | goto out; |
e3920fb4 | 1290 | |
84117da5 | 1291 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1292 | |
1293 | arch_enable_nonboot_cpus_begin(); | |
1294 | ||
e0b582ec | 1295 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1296 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1297 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1298 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1299 | if (!error) { |
84117da5 | 1300 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1301 | continue; |
1302 | } | |
84117da5 | 1303 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1304 | } |
d0af9eed SS |
1305 | |
1306 | arch_enable_nonboot_cpus_end(); | |
1307 | ||
e0b582ec | 1308 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1309 | out: |
d221938c | 1310 | cpu_maps_update_done(); |
1da177e4 | 1311 | } |
e0b582ec | 1312 | |
d7268a31 | 1313 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1314 | { |
1315 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1316 | return -ENOMEM; | |
1317 | return 0; | |
1318 | } | |
1319 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1320 | |
79cfbdfa SB |
1321 | /* |
1322 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1323 | * ensure that the state of the system with respect to the tasks being frozen | |
1324 | * or not, as reported by the notification, remains unchanged *throughout the | |
1325 | * duration* of the execution of the callbacks. | |
1326 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1327 | * | |
1328 | * This synchronization is implemented by mutually excluding regular CPU | |
1329 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1330 | * Hibernate notifications. | |
1331 | */ | |
1332 | static int | |
1333 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1334 | unsigned long action, void *ptr) | |
1335 | { | |
1336 | switch (action) { | |
1337 | ||
1338 | case PM_SUSPEND_PREPARE: | |
1339 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1340 | cpu_hotplug_disable(); |
79cfbdfa SB |
1341 | break; |
1342 | ||
1343 | case PM_POST_SUSPEND: | |
1344 | case PM_POST_HIBERNATION: | |
16e53dbf | 1345 | cpu_hotplug_enable(); |
79cfbdfa SB |
1346 | break; |
1347 | ||
1348 | default: | |
1349 | return NOTIFY_DONE; | |
1350 | } | |
1351 | ||
1352 | return NOTIFY_OK; | |
1353 | } | |
1354 | ||
1355 | ||
d7268a31 | 1356 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1357 | { |
6e32d479 FY |
1358 | /* |
1359 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1360 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1361 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1362 | */ | |
79cfbdfa SB |
1363 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1364 | return 0; | |
1365 | } | |
1366 | core_initcall(cpu_hotplug_pm_sync_init); | |
1367 | ||
f3de4be9 | 1368 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1369 | |
8ce371f9 PZ |
1370 | int __boot_cpu_id; |
1371 | ||
68f4f1ec | 1372 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1373 | |
cff7d378 | 1374 | /* Boot processor state steps */ |
17a2f1ce | 1375 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1376 | [CPUHP_OFFLINE] = { |
1377 | .name = "offline", | |
3c1627e9 TG |
1378 | .startup.single = NULL, |
1379 | .teardown.single = NULL, | |
cff7d378 TG |
1380 | }, |
1381 | #ifdef CONFIG_SMP | |
1382 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1383 | .name = "threads:prepare", |
3c1627e9 TG |
1384 | .startup.single = smpboot_create_threads, |
1385 | .teardown.single = NULL, | |
757c989b | 1386 | .cant_stop = true, |
cff7d378 | 1387 | }, |
00e16c3d | 1388 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1389 | .name = "perf:prepare", |
1390 | .startup.single = perf_event_init_cpu, | |
1391 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1392 | }, |
7ee681b2 | 1393 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1394 | .name = "workqueue:prepare", |
1395 | .startup.single = workqueue_prepare_cpu, | |
1396 | .teardown.single = NULL, | |
7ee681b2 | 1397 | }, |
27590dc1 | 1398 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1399 | .name = "hrtimers:prepare", |
1400 | .startup.single = hrtimers_prepare_cpu, | |
1401 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1402 | }, |
31487f83 | 1403 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1404 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1405 | .startup.single = smpcfd_prepare_cpu, |
1406 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1407 | }, |
e6d4989a RW |
1408 | [CPUHP_RELAY_PREPARE] = { |
1409 | .name = "relay:prepare", | |
1410 | .startup.single = relay_prepare_cpu, | |
1411 | .teardown.single = NULL, | |
1412 | }, | |
6731d4f1 SAS |
1413 | [CPUHP_SLAB_PREPARE] = { |
1414 | .name = "slab:prepare", | |
1415 | .startup.single = slab_prepare_cpu, | |
1416 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1417 | }, |
4df83742 | 1418 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1419 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1420 | .startup.single = rcutree_prepare_cpu, |
1421 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1422 | }, |
4fae16df RC |
1423 | /* |
1424 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1425 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1426 | * otherwise a RCU stall occurs. | |
1427 | */ | |
26456f87 | 1428 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1429 | .name = "timers:prepare", |
26456f87 | 1430 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1431 | .teardown.single = timers_dead_cpu, |
4fae16df | 1432 | }, |
d10ef6f9 | 1433 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1434 | [CPUHP_BRINGUP_CPU] = { |
1435 | .name = "cpu:bringup", | |
3c1627e9 TG |
1436 | .startup.single = bringup_cpu, |
1437 | .teardown.single = NULL, | |
757c989b | 1438 | .cant_stop = true, |
4baa0afc | 1439 | }, |
d10ef6f9 TG |
1440 | /* Final state before CPU kills itself */ |
1441 | [CPUHP_AP_IDLE_DEAD] = { | |
1442 | .name = "idle:dead", | |
1443 | }, | |
1444 | /* | |
1445 | * Last state before CPU enters the idle loop to die. Transient state | |
1446 | * for synchronization. | |
1447 | */ | |
1448 | [CPUHP_AP_OFFLINE] = { | |
1449 | .name = "ap:offline", | |
1450 | .cant_stop = true, | |
1451 | }, | |
9cf7243d TG |
1452 | /* First state is scheduler control. Interrupts are disabled */ |
1453 | [CPUHP_AP_SCHED_STARTING] = { | |
1454 | .name = "sched:starting", | |
3c1627e9 TG |
1455 | .startup.single = sched_cpu_starting, |
1456 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1457 | }, |
4df83742 | 1458 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1459 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1460 | .startup.single = NULL, |
1461 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1462 | }, |
46febd37 LJ |
1463 | [CPUHP_AP_SMPCFD_DYING] = { |
1464 | .name = "smpcfd:dying", | |
1465 | .startup.single = NULL, | |
1466 | .teardown.single = smpcfd_dying_cpu, | |
1467 | }, | |
d10ef6f9 TG |
1468 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1469 | * state for synchronsization */ | |
1470 | [CPUHP_AP_ONLINE] = { | |
1471 | .name = "ap:online", | |
1472 | }, | |
17a2f1ce LJ |
1473 | /* |
1474 | * Handled on controll processor until the plugged processor manages | |
1475 | * this itself. | |
1476 | */ | |
1477 | [CPUHP_TEARDOWN_CPU] = { | |
1478 | .name = "cpu:teardown", | |
1479 | .startup.single = NULL, | |
1480 | .teardown.single = takedown_cpu, | |
1481 | .cant_stop = true, | |
1482 | }, | |
d10ef6f9 | 1483 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1484 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1485 | .name = "smpboot/threads:online", |
3c1627e9 | 1486 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1487 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1488 | }, |
c5cb83bb TG |
1489 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1490 | .name = "irq/affinity:online", | |
1491 | .startup.single = irq_affinity_online_cpu, | |
1492 | .teardown.single = NULL, | |
1493 | }, | |
00e16c3d | 1494 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1495 | .name = "perf:online", |
1496 | .startup.single = perf_event_init_cpu, | |
1497 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1498 | }, |
9cf57731 PZ |
1499 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1500 | .name = "lockup_detector:online", | |
1501 | .startup.single = lockup_detector_online_cpu, | |
1502 | .teardown.single = lockup_detector_offline_cpu, | |
1503 | }, | |
7ee681b2 | 1504 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1505 | .name = "workqueue:online", |
1506 | .startup.single = workqueue_online_cpu, | |
1507 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1508 | }, |
4df83742 | 1509 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1510 | .name = "RCU/tree:online", |
3c1627e9 TG |
1511 | .startup.single = rcutree_online_cpu, |
1512 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1513 | }, |
4baa0afc | 1514 | #endif |
d10ef6f9 TG |
1515 | /* |
1516 | * The dynamically registered state space is here | |
1517 | */ | |
1518 | ||
aaddd7d1 TG |
1519 | #ifdef CONFIG_SMP |
1520 | /* Last state is scheduler control setting the cpu active */ | |
1521 | [CPUHP_AP_ACTIVE] = { | |
1522 | .name = "sched:active", | |
3c1627e9 TG |
1523 | .startup.single = sched_cpu_activate, |
1524 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1525 | }, |
1526 | #endif | |
1527 | ||
d10ef6f9 | 1528 | /* CPU is fully up and running. */ |
4baa0afc TG |
1529 | [CPUHP_ONLINE] = { |
1530 | .name = "online", | |
3c1627e9 TG |
1531 | .startup.single = NULL, |
1532 | .teardown.single = NULL, | |
4baa0afc TG |
1533 | }, |
1534 | }; | |
1535 | ||
5b7aa87e TG |
1536 | /* Sanity check for callbacks */ |
1537 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1538 | { | |
1539 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1540 | return -EINVAL; | |
1541 | return 0; | |
1542 | } | |
1543 | ||
dc280d93 TG |
1544 | /* |
1545 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1546 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1547 | * by having no name assigned. | |
1548 | */ | |
1549 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1550 | { | |
4205e478 TG |
1551 | enum cpuhp_state i, end; |
1552 | struct cpuhp_step *step; | |
dc280d93 | 1553 | |
4205e478 TG |
1554 | switch (state) { |
1555 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1556 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1557 | end = CPUHP_AP_ONLINE_DYN_END; |
1558 | break; | |
1559 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1560 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1561 | end = CPUHP_BP_PREPARE_DYN_END; |
1562 | break; | |
1563 | default: | |
1564 | return -EINVAL; | |
1565 | } | |
1566 | ||
1567 | for (i = state; i <= end; i++, step++) { | |
1568 | if (!step->name) | |
dc280d93 TG |
1569 | return i; |
1570 | } | |
1571 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1572 | return -ENOSPC; | |
1573 | } | |
1574 | ||
1575 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1576 | int (*startup)(unsigned int cpu), | |
1577 | int (*teardown)(unsigned int cpu), | |
1578 | bool multi_instance) | |
5b7aa87e TG |
1579 | { |
1580 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1581 | struct cpuhp_step *sp; | |
dc280d93 | 1582 | int ret = 0; |
5b7aa87e | 1583 | |
0c96b273 EB |
1584 | /* |
1585 | * If name is NULL, then the state gets removed. | |
1586 | * | |
1587 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1588 | * the first allocation from these dynamic ranges, so the removal | |
1589 | * would trigger a new allocation and clear the wrong (already | |
1590 | * empty) state, leaving the callbacks of the to be cleared state | |
1591 | * dangling, which causes wreckage on the next hotplug operation. | |
1592 | */ | |
1593 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1594 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1595 | ret = cpuhp_reserve_state(state); |
1596 | if (ret < 0) | |
dc434e05 | 1597 | return ret; |
dc280d93 TG |
1598 | state = ret; |
1599 | } | |
5b7aa87e | 1600 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1601 | if (name && sp->name) |
1602 | return -EBUSY; | |
1603 | ||
3c1627e9 TG |
1604 | sp->startup.single = startup; |
1605 | sp->teardown.single = teardown; | |
5b7aa87e | 1606 | sp->name = name; |
cf392d10 TG |
1607 | sp->multi_instance = multi_instance; |
1608 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1609 | return ret; |
5b7aa87e TG |
1610 | } |
1611 | ||
1612 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1613 | { | |
3c1627e9 | 1614 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1615 | } |
1616 | ||
5b7aa87e TG |
1617 | /* |
1618 | * Call the startup/teardown function for a step either on the AP or | |
1619 | * on the current CPU. | |
1620 | */ | |
cf392d10 TG |
1621 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1622 | struct hlist_node *node) | |
5b7aa87e | 1623 | { |
a724632c | 1624 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1625 | int ret; |
1626 | ||
4dddfb5f PZ |
1627 | /* |
1628 | * If there's nothing to do, we done. | |
1629 | * Relies on the union for multi_instance. | |
1630 | */ | |
3c1627e9 TG |
1631 | if ((bringup && !sp->startup.single) || |
1632 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1633 | return 0; |
5b7aa87e TG |
1634 | /* |
1635 | * The non AP bound callbacks can fail on bringup. On teardown | |
1636 | * e.g. module removal we crash for now. | |
1637 | */ | |
1cf4f629 TG |
1638 | #ifdef CONFIG_SMP |
1639 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1640 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1641 | else |
96abb968 | 1642 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1643 | #else |
96abb968 | 1644 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1645 | #endif |
5b7aa87e TG |
1646 | BUG_ON(ret && !bringup); |
1647 | return ret; | |
1648 | } | |
1649 | ||
1650 | /* | |
1651 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1652 | * | |
1653 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1654 | */ | |
1655 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1656 | struct hlist_node *node) |
5b7aa87e TG |
1657 | { |
1658 | int cpu; | |
1659 | ||
5b7aa87e TG |
1660 | /* Roll back the already executed steps on the other cpus */ |
1661 | for_each_present_cpu(cpu) { | |
1662 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1663 | int cpustate = st->state; | |
1664 | ||
1665 | if (cpu >= failedcpu) | |
1666 | break; | |
1667 | ||
1668 | /* Did we invoke the startup call on that cpu ? */ | |
1669 | if (cpustate >= state) | |
cf392d10 | 1670 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1671 | } |
1672 | } | |
1673 | ||
9805c673 TG |
1674 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1675 | struct hlist_node *node, | |
1676 | bool invoke) | |
cf392d10 TG |
1677 | { |
1678 | struct cpuhp_step *sp; | |
1679 | int cpu; | |
1680 | int ret; | |
1681 | ||
9805c673 TG |
1682 | lockdep_assert_cpus_held(); |
1683 | ||
cf392d10 TG |
1684 | sp = cpuhp_get_step(state); |
1685 | if (sp->multi_instance == false) | |
1686 | return -EINVAL; | |
1687 | ||
dc434e05 | 1688 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1689 | |
3c1627e9 | 1690 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1691 | goto add_node; |
1692 | ||
1693 | /* | |
1694 | * Try to call the startup callback for each present cpu | |
1695 | * depending on the hotplug state of the cpu. | |
1696 | */ | |
1697 | for_each_present_cpu(cpu) { | |
1698 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1699 | int cpustate = st->state; | |
1700 | ||
1701 | if (cpustate < state) | |
1702 | continue; | |
1703 | ||
1704 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1705 | if (ret) { | |
3c1627e9 | 1706 | if (sp->teardown.multi) |
cf392d10 | 1707 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1708 | goto unlock; |
cf392d10 TG |
1709 | } |
1710 | } | |
1711 | add_node: | |
1712 | ret = 0; | |
cf392d10 | 1713 | hlist_add_head(node, &sp->list); |
dc434e05 | 1714 | unlock: |
cf392d10 | 1715 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1716 | return ret; |
1717 | } | |
1718 | ||
1719 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1720 | bool invoke) | |
1721 | { | |
1722 | int ret; | |
1723 | ||
1724 | cpus_read_lock(); | |
1725 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1726 | cpus_read_unlock(); |
cf392d10 TG |
1727 | return ret; |
1728 | } | |
1729 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1730 | ||
5b7aa87e | 1731 | /** |
71def423 | 1732 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1733 | * @state: The state to setup |
1734 | * @invoke: If true, the startup function is invoked for cpus where | |
1735 | * cpu state >= @state | |
1736 | * @startup: startup callback function | |
1737 | * @teardown: teardown callback function | |
1738 | * @multi_instance: State is set up for multiple instances which get | |
1739 | * added afterwards. | |
5b7aa87e | 1740 | * |
71def423 | 1741 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1742 | * Returns: |
1743 | * On success: | |
1744 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1745 | * 0 for all other states | |
1746 | * On failure: proper (negative) error code | |
5b7aa87e | 1747 | */ |
71def423 SAS |
1748 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1749 | const char *name, bool invoke, | |
1750 | int (*startup)(unsigned int cpu), | |
1751 | int (*teardown)(unsigned int cpu), | |
1752 | bool multi_instance) | |
5b7aa87e TG |
1753 | { |
1754 | int cpu, ret = 0; | |
b9d9d691 | 1755 | bool dynstate; |
5b7aa87e | 1756 | |
71def423 SAS |
1757 | lockdep_assert_cpus_held(); |
1758 | ||
5b7aa87e TG |
1759 | if (cpuhp_cb_check(state) || !name) |
1760 | return -EINVAL; | |
1761 | ||
dc434e05 | 1762 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1763 | |
dc280d93 TG |
1764 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1765 | multi_instance); | |
5b7aa87e | 1766 | |
b9d9d691 TG |
1767 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1768 | if (ret > 0 && dynstate) { | |
1769 | state = ret; | |
1770 | ret = 0; | |
1771 | } | |
1772 | ||
dc280d93 | 1773 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1774 | goto out; |
1775 | ||
1776 | /* | |
1777 | * Try to call the startup callback for each present cpu | |
1778 | * depending on the hotplug state of the cpu. | |
1779 | */ | |
1780 | for_each_present_cpu(cpu) { | |
1781 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1782 | int cpustate = st->state; | |
1783 | ||
1784 | if (cpustate < state) | |
1785 | continue; | |
1786 | ||
cf392d10 | 1787 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1788 | if (ret) { |
a724632c | 1789 | if (teardown) |
cf392d10 TG |
1790 | cpuhp_rollback_install(cpu, state, NULL); |
1791 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1792 | goto out; |
1793 | } | |
1794 | } | |
1795 | out: | |
dc434e05 | 1796 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1797 | /* |
1798 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1799 | * dynamically allocated state in case of success. | |
1800 | */ | |
b9d9d691 | 1801 | if (!ret && dynstate) |
5b7aa87e TG |
1802 | return state; |
1803 | return ret; | |
1804 | } | |
71def423 SAS |
1805 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1806 | ||
1807 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1808 | const char *name, bool invoke, | |
1809 | int (*startup)(unsigned int cpu), | |
1810 | int (*teardown)(unsigned int cpu), | |
1811 | bool multi_instance) | |
1812 | { | |
1813 | int ret; | |
1814 | ||
1815 | cpus_read_lock(); | |
1816 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1817 | teardown, multi_instance); | |
1818 | cpus_read_unlock(); | |
1819 | return ret; | |
1820 | } | |
5b7aa87e TG |
1821 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1822 | ||
cf392d10 TG |
1823 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1824 | struct hlist_node *node, bool invoke) | |
1825 | { | |
1826 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1827 | int cpu; | |
1828 | ||
1829 | BUG_ON(cpuhp_cb_check(state)); | |
1830 | ||
1831 | if (!sp->multi_instance) | |
1832 | return -EINVAL; | |
1833 | ||
8f553c49 | 1834 | cpus_read_lock(); |
dc434e05 SAS |
1835 | mutex_lock(&cpuhp_state_mutex); |
1836 | ||
cf392d10 TG |
1837 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1838 | goto remove; | |
1839 | /* | |
1840 | * Call the teardown callback for each present cpu depending | |
1841 | * on the hotplug state of the cpu. This function is not | |
1842 | * allowed to fail currently! | |
1843 | */ | |
1844 | for_each_present_cpu(cpu) { | |
1845 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1846 | int cpustate = st->state; | |
1847 | ||
1848 | if (cpustate >= state) | |
1849 | cpuhp_issue_call(cpu, state, false, node); | |
1850 | } | |
1851 | ||
1852 | remove: | |
cf392d10 TG |
1853 | hlist_del(node); |
1854 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1855 | cpus_read_unlock(); |
cf392d10 TG |
1856 | |
1857 | return 0; | |
1858 | } | |
1859 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1860 | |
5b7aa87e | 1861 | /** |
71def423 | 1862 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1863 | * @state: The state to remove |
1864 | * @invoke: If true, the teardown function is invoked for cpus where | |
1865 | * cpu state >= @state | |
1866 | * | |
71def423 | 1867 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1868 | * The teardown callback is currently not allowed to fail. Think |
1869 | * about module removal! | |
1870 | */ | |
71def423 | 1871 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1872 | { |
cf392d10 | 1873 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1874 | int cpu; |
1875 | ||
1876 | BUG_ON(cpuhp_cb_check(state)); | |
1877 | ||
71def423 | 1878 | lockdep_assert_cpus_held(); |
5b7aa87e | 1879 | |
dc434e05 | 1880 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1881 | if (sp->multi_instance) { |
1882 | WARN(!hlist_empty(&sp->list), | |
1883 | "Error: Removing state %d which has instances left.\n", | |
1884 | state); | |
1885 | goto remove; | |
1886 | } | |
1887 | ||
a724632c | 1888 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1889 | goto remove; |
1890 | ||
1891 | /* | |
1892 | * Call the teardown callback for each present cpu depending | |
1893 | * on the hotplug state of the cpu. This function is not | |
1894 | * allowed to fail currently! | |
1895 | */ | |
1896 | for_each_present_cpu(cpu) { | |
1897 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1898 | int cpustate = st->state; | |
1899 | ||
1900 | if (cpustate >= state) | |
cf392d10 | 1901 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1902 | } |
1903 | remove: | |
cf392d10 | 1904 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1905 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1906 | } |
1907 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1908 | ||
1909 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1910 | { | |
1911 | cpus_read_lock(); | |
1912 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 1913 | cpus_read_unlock(); |
5b7aa87e TG |
1914 | } |
1915 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1916 | ||
dc8d37ed AB |
1917 | #ifdef CONFIG_HOTPLUG_SMT |
1918 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
1919 | { | |
1920 | struct device *dev = get_cpu_device(cpu); | |
1921 | ||
1922 | dev->offline = true; | |
1923 | /* Tell user space about the state change */ | |
1924 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
1925 | } | |
1926 | ||
1927 | static void cpuhp_online_cpu_device(unsigned int cpu) | |
1928 | { | |
1929 | struct device *dev = get_cpu_device(cpu); | |
1930 | ||
1931 | dev->offline = false; | |
1932 | /* Tell user space about the state change */ | |
1933 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
1934 | } | |
1935 | ||
1936 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) | |
1937 | { | |
1938 | int cpu, ret = 0; | |
1939 | ||
1940 | cpu_maps_update_begin(); | |
1941 | for_each_online_cpu(cpu) { | |
1942 | if (topology_is_primary_thread(cpu)) | |
1943 | continue; | |
1944 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
1945 | if (ret) | |
1946 | break; | |
1947 | /* | |
1948 | * As this needs to hold the cpu maps lock it's impossible | |
1949 | * to call device_offline() because that ends up calling | |
1950 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
1951 | * needs to be held as this might race against in kernel | |
1952 | * abusers of the hotplug machinery (thermal management). | |
1953 | * | |
1954 | * So nothing would update device:offline state. That would | |
1955 | * leave the sysfs entry stale and prevent onlining after | |
1956 | * smt control has been changed to 'off' again. This is | |
1957 | * called under the sysfs hotplug lock, so it is properly | |
1958 | * serialized against the regular offline usage. | |
1959 | */ | |
1960 | cpuhp_offline_cpu_device(cpu); | |
1961 | } | |
1962 | if (!ret) | |
1963 | cpu_smt_control = ctrlval; | |
1964 | cpu_maps_update_done(); | |
1965 | return ret; | |
1966 | } | |
1967 | ||
1968 | int cpuhp_smt_enable(void) | |
1969 | { | |
1970 | int cpu, ret = 0; | |
1971 | ||
1972 | cpu_maps_update_begin(); | |
1973 | cpu_smt_control = CPU_SMT_ENABLED; | |
1974 | for_each_present_cpu(cpu) { | |
1975 | /* Skip online CPUs and CPUs on offline nodes */ | |
1976 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
1977 | continue; | |
1978 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
1979 | if (ret) | |
1980 | break; | |
1981 | /* See comment in cpuhp_smt_disable() */ | |
1982 | cpuhp_online_cpu_device(cpu); | |
1983 | } | |
1984 | cpu_maps_update_done(); | |
1985 | return ret; | |
1986 | } | |
1987 | #endif | |
1988 | ||
98f8cdce TG |
1989 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1990 | static ssize_t show_cpuhp_state(struct device *dev, | |
1991 | struct device_attribute *attr, char *buf) | |
1992 | { | |
1993 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1994 | ||
1995 | return sprintf(buf, "%d\n", st->state); | |
1996 | } | |
1997 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1998 | ||
757c989b TG |
1999 | static ssize_t write_cpuhp_target(struct device *dev, |
2000 | struct device_attribute *attr, | |
2001 | const char *buf, size_t count) | |
2002 | { | |
2003 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2004 | struct cpuhp_step *sp; | |
2005 | int target, ret; | |
2006 | ||
2007 | ret = kstrtoint(buf, 10, &target); | |
2008 | if (ret) | |
2009 | return ret; | |
2010 | ||
2011 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
2012 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
2013 | return -EINVAL; | |
2014 | #else | |
2015 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
2016 | return -EINVAL; | |
2017 | #endif | |
2018 | ||
2019 | ret = lock_device_hotplug_sysfs(); | |
2020 | if (ret) | |
2021 | return ret; | |
2022 | ||
2023 | mutex_lock(&cpuhp_state_mutex); | |
2024 | sp = cpuhp_get_step(target); | |
2025 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
2026 | mutex_unlock(&cpuhp_state_mutex); | |
2027 | if (ret) | |
40da1b11 | 2028 | goto out; |
757c989b TG |
2029 | |
2030 | if (st->state < target) | |
2031 | ret = do_cpu_up(dev->id, target); | |
2032 | else | |
2033 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 2034 | out: |
757c989b TG |
2035 | unlock_device_hotplug(); |
2036 | return ret ? ret : count; | |
2037 | } | |
2038 | ||
98f8cdce TG |
2039 | static ssize_t show_cpuhp_target(struct device *dev, |
2040 | struct device_attribute *attr, char *buf) | |
2041 | { | |
2042 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2043 | ||
2044 | return sprintf(buf, "%d\n", st->target); | |
2045 | } | |
757c989b | 2046 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 2047 | |
1db49484 PZ |
2048 | |
2049 | static ssize_t write_cpuhp_fail(struct device *dev, | |
2050 | struct device_attribute *attr, | |
2051 | const char *buf, size_t count) | |
2052 | { | |
2053 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2054 | struct cpuhp_step *sp; | |
2055 | int fail, ret; | |
2056 | ||
2057 | ret = kstrtoint(buf, 10, &fail); | |
2058 | if (ret) | |
2059 | return ret; | |
2060 | ||
33d4a5a7 ET |
2061 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
2062 | return -EINVAL; | |
2063 | ||
1db49484 PZ |
2064 | /* |
2065 | * Cannot fail STARTING/DYING callbacks. | |
2066 | */ | |
2067 | if (cpuhp_is_atomic_state(fail)) | |
2068 | return -EINVAL; | |
2069 | ||
2070 | /* | |
2071 | * Cannot fail anything that doesn't have callbacks. | |
2072 | */ | |
2073 | mutex_lock(&cpuhp_state_mutex); | |
2074 | sp = cpuhp_get_step(fail); | |
2075 | if (!sp->startup.single && !sp->teardown.single) | |
2076 | ret = -EINVAL; | |
2077 | mutex_unlock(&cpuhp_state_mutex); | |
2078 | if (ret) | |
2079 | return ret; | |
2080 | ||
2081 | st->fail = fail; | |
2082 | ||
2083 | return count; | |
2084 | } | |
2085 | ||
2086 | static ssize_t show_cpuhp_fail(struct device *dev, | |
2087 | struct device_attribute *attr, char *buf) | |
2088 | { | |
2089 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2090 | ||
2091 | return sprintf(buf, "%d\n", st->fail); | |
2092 | } | |
2093 | ||
2094 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
2095 | ||
98f8cdce TG |
2096 | static struct attribute *cpuhp_cpu_attrs[] = { |
2097 | &dev_attr_state.attr, | |
2098 | &dev_attr_target.attr, | |
1db49484 | 2099 | &dev_attr_fail.attr, |
98f8cdce TG |
2100 | NULL |
2101 | }; | |
2102 | ||
993647a2 | 2103 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2104 | .attrs = cpuhp_cpu_attrs, |
2105 | .name = "hotplug", | |
2106 | NULL | |
2107 | }; | |
2108 | ||
2109 | static ssize_t show_cpuhp_states(struct device *dev, | |
2110 | struct device_attribute *attr, char *buf) | |
2111 | { | |
2112 | ssize_t cur, res = 0; | |
2113 | int i; | |
2114 | ||
2115 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2116 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2117 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2118 | ||
2119 | if (sp->name) { | |
2120 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2121 | buf += cur; | |
2122 | res += cur; | |
2123 | } | |
2124 | } | |
2125 | mutex_unlock(&cpuhp_state_mutex); | |
2126 | return res; | |
2127 | } | |
2128 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2129 | ||
2130 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2131 | &dev_attr_states.attr, | |
2132 | NULL | |
2133 | }; | |
2134 | ||
993647a2 | 2135 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2136 | .attrs = cpuhp_cpu_root_attrs, |
2137 | .name = "hotplug", | |
2138 | NULL | |
2139 | }; | |
2140 | ||
05736e4a TG |
2141 | #ifdef CONFIG_HOTPLUG_SMT |
2142 | ||
05736e4a | 2143 | static ssize_t |
de7b77e5 JP |
2144 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2145 | const char *buf, size_t count) | |
05736e4a TG |
2146 | { |
2147 | int ctrlval, ret; | |
2148 | ||
2149 | if (sysfs_streq(buf, "on")) | |
2150 | ctrlval = CPU_SMT_ENABLED; | |
2151 | else if (sysfs_streq(buf, "off")) | |
2152 | ctrlval = CPU_SMT_DISABLED; | |
2153 | else if (sysfs_streq(buf, "forceoff")) | |
2154 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2155 | else | |
2156 | return -EINVAL; | |
2157 | ||
2158 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2159 | return -EPERM; | |
2160 | ||
2161 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2162 | return -ENODEV; | |
2163 | ||
2164 | ret = lock_device_hotplug_sysfs(); | |
2165 | if (ret) | |
2166 | return ret; | |
2167 | ||
2168 | if (ctrlval != cpu_smt_control) { | |
2169 | switch (ctrlval) { | |
2170 | case CPU_SMT_ENABLED: | |
215af549 | 2171 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2172 | break; |
2173 | case CPU_SMT_DISABLED: | |
2174 | case CPU_SMT_FORCE_DISABLED: | |
2175 | ret = cpuhp_smt_disable(ctrlval); | |
2176 | break; | |
2177 | } | |
2178 | } | |
2179 | ||
2180 | unlock_device_hotplug(); | |
2181 | return ret ? ret : count; | |
2182 | } | |
de7b77e5 JP |
2183 | |
2184 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2185 | static ssize_t | |
2186 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2187 | const char *buf, size_t count) | |
2188 | { | |
2189 | return -ENODEV; | |
2190 | } | |
2191 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2192 | ||
2193 | static const char *smt_states[] = { | |
2194 | [CPU_SMT_ENABLED] = "on", | |
2195 | [CPU_SMT_DISABLED] = "off", | |
2196 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2197 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2198 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2199 | }; | |
2200 | ||
2201 | static ssize_t | |
2202 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2203 | { | |
2204 | const char *state = smt_states[cpu_smt_control]; | |
2205 | ||
2206 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2207 | } | |
2208 | ||
2209 | static ssize_t | |
2210 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2211 | const char *buf, size_t count) | |
2212 | { | |
2213 | return __store_smt_control(dev, attr, buf, count); | |
2214 | } | |
05736e4a TG |
2215 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
2216 | ||
2217 | static ssize_t | |
2218 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2219 | { | |
de7b77e5 | 2220 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a TG |
2221 | } |
2222 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2223 | ||
2224 | static struct attribute *cpuhp_smt_attrs[] = { | |
2225 | &dev_attr_control.attr, | |
2226 | &dev_attr_active.attr, | |
2227 | NULL | |
2228 | }; | |
2229 | ||
2230 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2231 | .attrs = cpuhp_smt_attrs, | |
2232 | .name = "smt", | |
2233 | NULL | |
2234 | }; | |
2235 | ||
de7b77e5 | 2236 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2237 | { |
05736e4a TG |
2238 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2239 | &cpuhp_smt_attr_group); | |
2240 | } | |
2241 | ||
98f8cdce TG |
2242 | static int __init cpuhp_sysfs_init(void) |
2243 | { | |
2244 | int cpu, ret; | |
2245 | ||
de7b77e5 | 2246 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2247 | if (ret) |
2248 | return ret; | |
2249 | ||
98f8cdce TG |
2250 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2251 | &cpuhp_cpu_root_attr_group); | |
2252 | if (ret) | |
2253 | return ret; | |
2254 | ||
2255 | for_each_possible_cpu(cpu) { | |
2256 | struct device *dev = get_cpu_device(cpu); | |
2257 | ||
2258 | if (!dev) | |
2259 | continue; | |
2260 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2261 | if (ret) | |
2262 | return ret; | |
2263 | } | |
2264 | return 0; | |
2265 | } | |
2266 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2267 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2268 | |
e56b3bc7 LT |
2269 | /* |
2270 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2271 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2272 | * | |
e0b582ec | 2273 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2274 | * mask value that has a single bit set only. |
2275 | */ | |
b8d317d1 | 2276 | |
e56b3bc7 | 2277 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2278 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2279 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2280 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2281 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2282 | |
e56b3bc7 LT |
2283 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2284 | ||
2285 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2286 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2287 | #if BITS_PER_LONG > 32 | |
2288 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2289 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2290 | #endif |
2291 | }; | |
e56b3bc7 | 2292 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2293 | |
2294 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2295 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2296 | |
2297 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2298 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2299 | = {CPU_BITS_ALL}; |
b3199c02 | 2300 | #else |
4b804c85 | 2301 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2302 | #endif |
4b804c85 | 2303 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2304 | |
4b804c85 RV |
2305 | struct cpumask __cpu_online_mask __read_mostly; |
2306 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2307 | |
4b804c85 RV |
2308 | struct cpumask __cpu_present_mask __read_mostly; |
2309 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2310 | |
4b804c85 RV |
2311 | struct cpumask __cpu_active_mask __read_mostly; |
2312 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2313 | |
0c09ab96 TG |
2314 | atomic_t __num_online_cpus __read_mostly; |
2315 | EXPORT_SYMBOL(__num_online_cpus); | |
2316 | ||
3fa41520 RR |
2317 | void init_cpu_present(const struct cpumask *src) |
2318 | { | |
c4c54dd1 | 2319 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2320 | } |
2321 | ||
2322 | void init_cpu_possible(const struct cpumask *src) | |
2323 | { | |
c4c54dd1 | 2324 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2325 | } |
2326 | ||
2327 | void init_cpu_online(const struct cpumask *src) | |
2328 | { | |
c4c54dd1 | 2329 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2330 | } |
cff7d378 | 2331 | |
0c09ab96 TG |
2332 | void set_cpu_online(unsigned int cpu, bool online) |
2333 | { | |
2334 | /* | |
2335 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2336 | * function by the reboot and kexec code which invoke it from | |
2337 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2338 | * regular CPU hotplug is properly serialized. | |
2339 | * | |
2340 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2341 | * does not protect readers which are not serialized against | |
2342 | * concurrent hotplug operations. | |
2343 | */ | |
2344 | if (online) { | |
2345 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2346 | atomic_inc(&__num_online_cpus); | |
2347 | } else { | |
2348 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2349 | atomic_dec(&__num_online_cpus); | |
2350 | } | |
2351 | } | |
2352 | ||
cff7d378 TG |
2353 | /* |
2354 | * Activate the first processor. | |
2355 | */ | |
2356 | void __init boot_cpu_init(void) | |
2357 | { | |
2358 | int cpu = smp_processor_id(); | |
2359 | ||
2360 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2361 | set_cpu_online(cpu, true); | |
2362 | set_cpu_active(cpu, true); | |
2363 | set_cpu_present(cpu, true); | |
2364 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2365 | |
2366 | #ifdef CONFIG_SMP | |
2367 | __boot_cpu_id = cpu; | |
2368 | #endif | |
cff7d378 TG |
2369 | } |
2370 | ||
2371 | /* | |
2372 | * Must be called _AFTER_ setting up the per_cpu areas | |
2373 | */ | |
b5b1404d | 2374 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2375 | { |
269777aa | 2376 | #ifdef CONFIG_SMP |
e797bda3 | 2377 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2378 | #endif |
0cc3cd21 | 2379 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2380 | } |
98af8452 | 2381 | |
731dc9df TH |
2382 | /* |
2383 | * These are used for a global "mitigations=" cmdline option for toggling | |
2384 | * optional CPU mitigations. | |
2385 | */ | |
2386 | enum cpu_mitigations { | |
2387 | CPU_MITIGATIONS_OFF, | |
2388 | CPU_MITIGATIONS_AUTO, | |
2389 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2390 | }; | |
2391 | ||
2392 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2393 | CPU_MITIGATIONS_AUTO; | |
98af8452 JP |
2394 | |
2395 | static int __init mitigations_parse_cmdline(char *arg) | |
2396 | { | |
2397 | if (!strcmp(arg, "off")) | |
2398 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2399 | else if (!strcmp(arg, "auto")) | |
2400 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2401 | else if (!strcmp(arg, "auto,nosmt")) | |
2402 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2403 | else |
2404 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2405 | arg); | |
98af8452 JP |
2406 | |
2407 | return 0; | |
2408 | } | |
2409 | early_param("mitigations", mitigations_parse_cmdline); | |
731dc9df TH |
2410 | |
2411 | /* mitigations=off */ | |
2412 | bool cpu_mitigations_off(void) | |
2413 | { | |
2414 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2415 | } | |
2416 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2417 | ||
2418 | /* mitigations=auto,nosmt */ | |
2419 | bool cpu_mitigations_auto_nosmt(void) | |
2420 | { | |
2421 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2422 | } | |
2423 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |