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Commit | Line | Data |
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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; | |
0cc3cd21 | 65 | bool booted_once; |
cf392d10 | 66 | struct hlist_node *node; |
4dddfb5f | 67 | struct hlist_node *last; |
4cb28ced | 68 | enum cpuhp_state cb_state; |
4cb28ced | 69 | int result; |
5ebe7742 PZ |
70 | struct completion done_up; |
71 | struct completion done_down; | |
4cb28ced | 72 | #endif |
cff7d378 TG |
73 | }; |
74 | ||
1db49484 PZ |
75 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
76 | .fail = CPUHP_INVALID, | |
77 | }; | |
cff7d378 | 78 | |
49dfe2a6 | 79 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
80 | static struct lockdep_map cpuhp_state_up_map = |
81 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
82 | static struct lockdep_map cpuhp_state_down_map = | |
83 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
84 | ||
85 | ||
76dc6c09 | 86 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
87 | { |
88 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
89 | } | |
90 | ||
76dc6c09 | 91 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
92 | { |
93 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
94 | } | |
95 | #else | |
96 | ||
76dc6c09 MM |
97 | static inline void cpuhp_lock_acquire(bool bringup) { } |
98 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 99 | |
49dfe2a6 TG |
100 | #endif |
101 | ||
cff7d378 TG |
102 | /** |
103 | * cpuhp_step - Hotplug state machine step | |
104 | * @name: Name of the step | |
105 | * @startup: Startup function of the step | |
106 | * @teardown: Teardown function of the step | |
757c989b | 107 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
108 | */ |
109 | struct cpuhp_step { | |
cf392d10 TG |
110 | const char *name; |
111 | union { | |
3c1627e9 TG |
112 | int (*single)(unsigned int cpu); |
113 | int (*multi)(unsigned int cpu, | |
114 | struct hlist_node *node); | |
115 | } startup; | |
cf392d10 | 116 | union { |
3c1627e9 TG |
117 | int (*single)(unsigned int cpu); |
118 | int (*multi)(unsigned int cpu, | |
119 | struct hlist_node *node); | |
120 | } teardown; | |
cf392d10 | 121 | struct hlist_head list; |
cf392d10 TG |
122 | bool cant_stop; |
123 | bool multi_instance; | |
cff7d378 TG |
124 | }; |
125 | ||
98f8cdce | 126 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 127 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 128 | |
a724632c TG |
129 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
130 | { | |
17a2f1ce | 131 | return cpuhp_hp_states + state; |
a724632c TG |
132 | } |
133 | ||
cff7d378 TG |
134 | /** |
135 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
136 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 137 | * @state: The state to do callbacks for |
a724632c | 138 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
139 | * @node: For multi-instance, do a single entry callback for install/remove |
140 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 141 | * |
cf392d10 | 142 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 143 | */ |
a724632c | 144 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
145 | bool bringup, struct hlist_node *node, |
146 | struct hlist_node **lastp) | |
cff7d378 TG |
147 | { |
148 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 149 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
150 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
151 | int (*cb)(unsigned int cpu); | |
152 | int ret, cnt; | |
153 | ||
1db49484 PZ |
154 | if (st->fail == state) { |
155 | st->fail = CPUHP_INVALID; | |
156 | ||
157 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
158 | return 0; | |
159 | ||
160 | return -EAGAIN; | |
161 | } | |
162 | ||
cf392d10 | 163 | if (!step->multi_instance) { |
96abb968 | 164 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 165 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
166 | if (!cb) |
167 | return 0; | |
a724632c | 168 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 169 | ret = cb(cpu); |
a724632c | 170 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
171 | return ret; |
172 | } | |
3c1627e9 | 173 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
174 | if (!cbm) |
175 | return 0; | |
176 | ||
177 | /* Single invocation for instance add/remove */ | |
178 | if (node) { | |
96abb968 | 179 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
180 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
181 | ret = cbm(cpu, node); | |
182 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
183 | return ret; | |
184 | } | |
185 | ||
186 | /* State transition. Invoke on all instances */ | |
187 | cnt = 0; | |
188 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
189 | if (lastp && node == *lastp) |
190 | break; | |
191 | ||
cf392d10 TG |
192 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
193 | ret = cbm(cpu, node); | |
194 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
195 | if (ret) { |
196 | if (!lastp) | |
197 | goto err; | |
198 | ||
199 | *lastp = node; | |
200 | return ret; | |
201 | } | |
cf392d10 TG |
202 | cnt++; |
203 | } | |
96abb968 PZ |
204 | if (lastp) |
205 | *lastp = NULL; | |
cf392d10 TG |
206 | return 0; |
207 | err: | |
208 | /* Rollback the instances if one failed */ | |
3c1627e9 | 209 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
210 | if (!cbm) |
211 | return ret; | |
212 | ||
213 | hlist_for_each(node, &step->list) { | |
214 | if (!cnt--) | |
215 | break; | |
724a8688 PZ |
216 | |
217 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
218 | ret = cbm(cpu, node); | |
219 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
220 | /* | |
221 | * Rollback must not fail, | |
222 | */ | |
223 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
224 | } |
225 | return ret; | |
226 | } | |
227 | ||
98a79d6a | 228 | #ifdef CONFIG_SMP |
fcb3029a AB |
229 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
230 | { | |
231 | /* | |
232 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
233 | * purposes as that state is handled explicitly in cpu_down. | |
234 | */ | |
235 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
236 | } | |
237 | ||
5ebe7742 PZ |
238 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
239 | { | |
240 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
241 | wait_for_completion(done); | |
242 | } | |
243 | ||
244 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
245 | { | |
246 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
247 | complete(done); | |
248 | } | |
249 | ||
250 | /* | |
251 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
252 | */ | |
253 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
254 | { | |
255 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
256 | } | |
257 | ||
b3199c02 | 258 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 259 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
260 | bool cpuhp_tasks_frozen; |
261 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 262 | |
79a6cdeb | 263 | /* |
93ae4f97 SB |
264 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
265 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
266 | */ |
267 | void cpu_maps_update_begin(void) | |
268 | { | |
269 | mutex_lock(&cpu_add_remove_lock); | |
270 | } | |
271 | ||
272 | void cpu_maps_update_done(void) | |
273 | { | |
274 | mutex_unlock(&cpu_add_remove_lock); | |
275 | } | |
1da177e4 | 276 | |
fc8dffd3 TG |
277 | /* |
278 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
279 | * Should always be manipulated under cpu_add_remove_lock |
280 | */ | |
281 | static int cpu_hotplug_disabled; | |
282 | ||
79a6cdeb LJ |
283 | #ifdef CONFIG_HOTPLUG_CPU |
284 | ||
fc8dffd3 | 285 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 286 | |
8f553c49 | 287 | void cpus_read_lock(void) |
a9d9baa1 | 288 | { |
fc8dffd3 | 289 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 290 | } |
8f553c49 | 291 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 292 | |
6f4ceee9 WL |
293 | int cpus_read_trylock(void) |
294 | { | |
295 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
296 | } | |
297 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
298 | ||
8f553c49 | 299 | void cpus_read_unlock(void) |
a9d9baa1 | 300 | { |
fc8dffd3 | 301 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 302 | } |
8f553c49 | 303 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 304 | |
8f553c49 | 305 | void cpus_write_lock(void) |
d221938c | 306 | { |
fc8dffd3 | 307 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 308 | } |
87af9e7f | 309 | |
8f553c49 | 310 | void cpus_write_unlock(void) |
d221938c | 311 | { |
fc8dffd3 | 312 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
313 | } |
314 | ||
fc8dffd3 | 315 | void lockdep_assert_cpus_held(void) |
d221938c | 316 | { |
ce48c457 VS |
317 | /* |
318 | * We can't have hotplug operations before userspace starts running, | |
319 | * and some init codepaths will knowingly not take the hotplug lock. | |
320 | * This is all valid, so mute lockdep until it makes sense to report | |
321 | * unheld locks. | |
322 | */ | |
323 | if (system_state < SYSTEM_RUNNING) | |
324 | return; | |
325 | ||
fc8dffd3 | 326 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 327 | } |
79a6cdeb | 328 | |
cb92173d PZ |
329 | static void lockdep_acquire_cpus_lock(void) |
330 | { | |
331 | rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_); | |
332 | } | |
333 | ||
334 | static void lockdep_release_cpus_lock(void) | |
335 | { | |
336 | rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, 1, _THIS_IP_); | |
337 | } | |
338 | ||
16e53dbf SB |
339 | /* |
340 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
341 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
342 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
343 | * hotplug path before performing hotplug operations. So acquiring that lock | |
344 | * guarantees mutual exclusion from any currently running hotplug operations. | |
345 | */ | |
346 | void cpu_hotplug_disable(void) | |
347 | { | |
348 | cpu_maps_update_begin(); | |
89af7ba5 | 349 | cpu_hotplug_disabled++; |
16e53dbf SB |
350 | cpu_maps_update_done(); |
351 | } | |
32145c46 | 352 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 353 | |
01b41159 LW |
354 | static void __cpu_hotplug_enable(void) |
355 | { | |
356 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
357 | return; | |
358 | cpu_hotplug_disabled--; | |
359 | } | |
360 | ||
16e53dbf SB |
361 | void cpu_hotplug_enable(void) |
362 | { | |
363 | cpu_maps_update_begin(); | |
01b41159 | 364 | __cpu_hotplug_enable(); |
16e53dbf SB |
365 | cpu_maps_update_done(); |
366 | } | |
32145c46 | 367 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
368 | |
369 | #else | |
370 | ||
371 | static void lockdep_acquire_cpus_lock(void) | |
372 | { | |
373 | } | |
374 | ||
375 | static void lockdep_release_cpus_lock(void) | |
376 | { | |
377 | } | |
378 | ||
b9d10be7 | 379 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 380 | |
a74cfffb TG |
381 | /* |
382 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
383 | * should override this. | |
384 | */ | |
385 | void __weak arch_smt_update(void) { } | |
386 | ||
0cc3cd21 TG |
387 | #ifdef CONFIG_HOTPLUG_SMT |
388 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 389 | |
8e1b706b | 390 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 391 | { |
8e1b706b JK |
392 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || |
393 | cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
394 | return; | |
395 | ||
396 | if (force) { | |
0cc3cd21 TG |
397 | pr_info("SMT: Force disabled\n"); |
398 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 399 | } else { |
d0e7d144 | 400 | pr_info("SMT: disabled\n"); |
8e1b706b | 401 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 402 | } |
8e1b706b JK |
403 | } |
404 | ||
fee0aede TG |
405 | /* |
406 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 407 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
408 | */ |
409 | void __init cpu_smt_check_topology(void) | |
410 | { | |
b284909a | 411 | if (!topology_smt_supported()) |
bc2d8d26 TG |
412 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
413 | } | |
414 | ||
8e1b706b JK |
415 | static int __init smt_cmdline_disable(char *str) |
416 | { | |
417 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
418 | return 0; |
419 | } | |
420 | early_param("nosmt", smt_cmdline_disable); | |
421 | ||
422 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
423 | { | |
b284909a | 424 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
425 | return true; |
426 | ||
b284909a | 427 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
428 | return true; |
429 | ||
430 | /* | |
431 | * On x86 it's required to boot all logical CPUs at least once so | |
432 | * that the init code can get a chance to set CR4.MCE on each | |
433 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any | |
434 | * core will shutdown the machine. | |
435 | */ | |
436 | return !per_cpu(cpuhp_state, cpu).booted_once; | |
437 | } | |
438 | #else | |
439 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
440 | #endif | |
441 | ||
4dddfb5f PZ |
442 | static inline enum cpuhp_state |
443 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
444 | { | |
445 | enum cpuhp_state prev_state = st->state; | |
446 | ||
447 | st->rollback = false; | |
448 | st->last = NULL; | |
449 | ||
450 | st->target = target; | |
451 | st->single = false; | |
452 | st->bringup = st->state < target; | |
453 | ||
454 | return prev_state; | |
455 | } | |
456 | ||
457 | static inline void | |
458 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
459 | { | |
460 | st->rollback = true; | |
461 | ||
462 | /* | |
463 | * If we have st->last we need to undo partial multi_instance of this | |
464 | * state first. Otherwise start undo at the previous state. | |
465 | */ | |
466 | if (!st->last) { | |
467 | if (st->bringup) | |
468 | st->state--; | |
469 | else | |
470 | st->state++; | |
471 | } | |
472 | ||
473 | st->target = prev_state; | |
474 | st->bringup = !st->bringup; | |
475 | } | |
476 | ||
477 | /* Regular hotplug invocation of the AP hotplug thread */ | |
478 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
479 | { | |
480 | if (!st->single && st->state == st->target) | |
481 | return; | |
482 | ||
483 | st->result = 0; | |
484 | /* | |
485 | * Make sure the above stores are visible before should_run becomes | |
486 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
487 | */ | |
488 | smp_mb(); | |
489 | st->should_run = true; | |
490 | wake_up_process(st->thread); | |
5ebe7742 | 491 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
492 | } |
493 | ||
494 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
495 | { | |
496 | enum cpuhp_state prev_state; | |
497 | int ret; | |
498 | ||
499 | prev_state = cpuhp_set_state(st, target); | |
500 | __cpuhp_kick_ap(st); | |
501 | if ((ret = st->result)) { | |
502 | cpuhp_reset_state(st, prev_state); | |
503 | __cpuhp_kick_ap(st); | |
504 | } | |
505 | ||
506 | return ret; | |
507 | } | |
9cd4f1a4 | 508 | |
8df3e07e TG |
509 | static int bringup_wait_for_ap(unsigned int cpu) |
510 | { | |
511 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
512 | ||
9cd4f1a4 | 513 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 514 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
515 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
516 | return -ECANCELED; | |
9cd4f1a4 TG |
517 | |
518 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ | |
519 | stop_machine_unpark(cpu); | |
520 | kthread_unpark(st->thread); | |
521 | ||
0cc3cd21 TG |
522 | /* |
523 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
524 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 525 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
526 | * cpu_smt_allowed() check will now return false if this is not the |
527 | * primary sibling. | |
528 | */ | |
529 | if (!cpu_smt_allowed(cpu)) | |
530 | return -ECANCELED; | |
531 | ||
4dddfb5f PZ |
532 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
533 | return 0; | |
534 | ||
535 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
536 | } |
537 | ||
ba997462 TG |
538 | static int bringup_cpu(unsigned int cpu) |
539 | { | |
540 | struct task_struct *idle = idle_thread_get(cpu); | |
541 | int ret; | |
542 | ||
aa877175 BO |
543 | /* |
544 | * Some architectures have to walk the irq descriptors to | |
545 | * setup the vector space for the cpu which comes online. | |
546 | * Prevent irq alloc/free across the bringup. | |
547 | */ | |
548 | irq_lock_sparse(); | |
549 | ||
ba997462 TG |
550 | /* Arch-specific enabling code. */ |
551 | ret = __cpu_up(cpu, idle); | |
aa877175 | 552 | irq_unlock_sparse(); |
530e9b76 | 553 | if (ret) |
ba997462 | 554 | return ret; |
9cd4f1a4 | 555 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
556 | } |
557 | ||
2e1a3483 TG |
558 | /* |
559 | * Hotplug state machine related functions | |
560 | */ | |
2e1a3483 | 561 | |
a724632c | 562 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 | 563 | { |
6fb86d97 MO |
564 | for (st->state--; st->state > st->target; st->state--) |
565 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
2e1a3483 TG |
566 | } |
567 | ||
206b9235 TG |
568 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
569 | { | |
570 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
571 | return true; | |
572 | /* | |
573 | * When CPU hotplug is disabled, then taking the CPU down is not | |
574 | * possible because takedown_cpu() and the architecture and | |
575 | * subsystem specific mechanisms are not available. So the CPU | |
576 | * which would be completely unplugged again needs to stay around | |
577 | * in the current state. | |
578 | */ | |
579 | return st->state <= CPUHP_BRINGUP_CPU; | |
580 | } | |
581 | ||
2e1a3483 | 582 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 583 | enum cpuhp_state target) |
2e1a3483 TG |
584 | { |
585 | enum cpuhp_state prev_state = st->state; | |
586 | int ret = 0; | |
587 | ||
588 | while (st->state < target) { | |
2e1a3483 | 589 | st->state++; |
96abb968 | 590 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 | 591 | if (ret) { |
206b9235 TG |
592 | if (can_rollback_cpu(st)) { |
593 | st->target = prev_state; | |
594 | undo_cpu_up(cpu, st); | |
595 | } | |
2e1a3483 TG |
596 | break; |
597 | } | |
598 | } | |
599 | return ret; | |
600 | } | |
601 | ||
4cb28ced TG |
602 | /* |
603 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
604 | */ | |
605 | static void cpuhp_create(unsigned int cpu) | |
606 | { | |
607 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
608 | ||
5ebe7742 PZ |
609 | init_completion(&st->done_up); |
610 | init_completion(&st->done_down); | |
4cb28ced TG |
611 | } |
612 | ||
613 | static int cpuhp_should_run(unsigned int cpu) | |
614 | { | |
615 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
616 | ||
617 | return st->should_run; | |
618 | } | |
619 | ||
4cb28ced TG |
620 | /* |
621 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
622 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
623 | * |
624 | * Each invocation of this function by the smpboot thread does a single AP | |
625 | * state callback. | |
626 | * | |
627 | * It has 3 modes of operation: | |
628 | * - single: runs st->cb_state | |
629 | * - up: runs ++st->state, while st->state < st->target | |
630 | * - down: runs st->state--, while st->state > st->target | |
631 | * | |
632 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
633 | */ |
634 | static void cpuhp_thread_fun(unsigned int cpu) | |
635 | { | |
636 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
637 | bool bringup = st->bringup; |
638 | enum cpuhp_state state; | |
4cb28ced | 639 | |
f8b7530a NU |
640 | if (WARN_ON_ONCE(!st->should_run)) |
641 | return; | |
642 | ||
4cb28ced | 643 | /* |
4dddfb5f PZ |
644 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
645 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
646 | */ |
647 | smp_mb(); | |
4cb28ced | 648 | |
cb92173d PZ |
649 | /* |
650 | * The BP holds the hotplug lock, but we're now running on the AP, | |
651 | * ensure that anybody asserting the lock is held, will actually find | |
652 | * it so. | |
653 | */ | |
654 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 655 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 656 | |
a724632c | 657 | if (st->single) { |
4dddfb5f PZ |
658 | state = st->cb_state; |
659 | st->should_run = false; | |
660 | } else { | |
661 | if (bringup) { | |
662 | st->state++; | |
663 | state = st->state; | |
664 | st->should_run = (st->state < st->target); | |
665 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 666 | } else { |
4dddfb5f PZ |
667 | state = st->state; |
668 | st->state--; | |
669 | st->should_run = (st->state > st->target); | |
670 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 671 | } |
4dddfb5f PZ |
672 | } |
673 | ||
674 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
675 | ||
4dddfb5f PZ |
676 | if (cpuhp_is_atomic_state(state)) { |
677 | local_irq_disable(); | |
678 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
679 | local_irq_enable(); | |
3b9d6da6 | 680 | |
4dddfb5f PZ |
681 | /* |
682 | * STARTING/DYING must not fail! | |
683 | */ | |
684 | WARN_ON_ONCE(st->result); | |
4cb28ced | 685 | } else { |
4dddfb5f PZ |
686 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
687 | } | |
688 | ||
689 | if (st->result) { | |
690 | /* | |
691 | * If we fail on a rollback, we're up a creek without no | |
692 | * paddle, no way forward, no way back. We loose, thanks for | |
693 | * playing. | |
694 | */ | |
695 | WARN_ON_ONCE(st->rollback); | |
696 | st->should_run = false; | |
4cb28ced | 697 | } |
4dddfb5f | 698 | |
5f4b55e1 | 699 | cpuhp_lock_release(bringup); |
cb92173d | 700 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
701 | |
702 | if (!st->should_run) | |
5ebe7742 | 703 | complete_ap_thread(st, bringup); |
4cb28ced TG |
704 | } |
705 | ||
706 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 707 | static int |
cf392d10 TG |
708 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
709 | struct hlist_node *node) | |
4cb28ced TG |
710 | { |
711 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 712 | int ret; |
4cb28ced TG |
713 | |
714 | if (!cpu_online(cpu)) | |
715 | return 0; | |
716 | ||
5f4b55e1 PZ |
717 | cpuhp_lock_acquire(false); |
718 | cpuhp_lock_release(false); | |
719 | ||
720 | cpuhp_lock_acquire(true); | |
721 | cpuhp_lock_release(true); | |
49dfe2a6 | 722 | |
6a4e2451 TG |
723 | /* |
724 | * If we are up and running, use the hotplug thread. For early calls | |
725 | * we invoke the thread function directly. | |
726 | */ | |
727 | if (!st->thread) | |
96abb968 | 728 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 729 | |
4dddfb5f PZ |
730 | st->rollback = false; |
731 | st->last = NULL; | |
732 | ||
733 | st->node = node; | |
734 | st->bringup = bringup; | |
4cb28ced | 735 | st->cb_state = state; |
a724632c | 736 | st->single = true; |
a724632c | 737 | |
4dddfb5f | 738 | __cpuhp_kick_ap(st); |
4cb28ced | 739 | |
4cb28ced | 740 | /* |
4dddfb5f | 741 | * If we failed and did a partial, do a rollback. |
4cb28ced | 742 | */ |
4dddfb5f PZ |
743 | if ((ret = st->result) && st->last) { |
744 | st->rollback = true; | |
745 | st->bringup = !bringup; | |
746 | ||
747 | __cpuhp_kick_ap(st); | |
748 | } | |
749 | ||
1f7c70d6 TG |
750 | /* |
751 | * Clean up the leftovers so the next hotplug operation wont use stale | |
752 | * data. | |
753 | */ | |
754 | st->node = st->last = NULL; | |
4dddfb5f | 755 | return ret; |
1cf4f629 TG |
756 | } |
757 | ||
758 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
759 | { | |
760 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
761 | enum cpuhp_state prev_state = st->state; |
762 | int ret; | |
1cf4f629 | 763 | |
5f4b55e1 PZ |
764 | cpuhp_lock_acquire(false); |
765 | cpuhp_lock_release(false); | |
766 | ||
767 | cpuhp_lock_acquire(true); | |
768 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
769 | |
770 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
771 | ret = cpuhp_kick_ap(st, st->target); | |
772 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
773 | ||
774 | return ret; | |
4cb28ced TG |
775 | } |
776 | ||
777 | static struct smp_hotplug_thread cpuhp_threads = { | |
778 | .store = &cpuhp_state.thread, | |
779 | .create = &cpuhp_create, | |
780 | .thread_should_run = cpuhp_should_run, | |
781 | .thread_fn = cpuhp_thread_fun, | |
782 | .thread_comm = "cpuhp/%u", | |
783 | .selfparking = true, | |
784 | }; | |
785 | ||
786 | void __init cpuhp_threads_init(void) | |
787 | { | |
788 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
789 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
790 | } | |
791 | ||
777c6e0d | 792 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
793 | /** |
794 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
795 | * @cpu: a CPU id | |
796 | * | |
797 | * This function walks all processes, finds a valid mm struct for each one and | |
798 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
799 | * trivial, there are various non-obvious corner cases, which this function | |
800 | * tries to solve in a safe manner. | |
801 | * | |
802 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
803 | * be called only for an already offlined CPU. | |
804 | */ | |
cb79295e AV |
805 | void clear_tasks_mm_cpumask(int cpu) |
806 | { | |
807 | struct task_struct *p; | |
808 | ||
809 | /* | |
810 | * This function is called after the cpu is taken down and marked | |
811 | * offline, so its not like new tasks will ever get this cpu set in | |
812 | * their mm mask. -- Peter Zijlstra | |
813 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
814 | * full-fledged tasklist_lock. | |
815 | */ | |
e4cc2f87 | 816 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
817 | rcu_read_lock(); |
818 | for_each_process(p) { | |
819 | struct task_struct *t; | |
820 | ||
e4cc2f87 AV |
821 | /* |
822 | * Main thread might exit, but other threads may still have | |
823 | * a valid mm. Find one. | |
824 | */ | |
cb79295e AV |
825 | t = find_lock_task_mm(p); |
826 | if (!t) | |
827 | continue; | |
828 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
829 | task_unlock(t); | |
830 | } | |
831 | rcu_read_unlock(); | |
832 | } | |
833 | ||
1da177e4 | 834 | /* Take this CPU down. */ |
71cf5aee | 835 | static int take_cpu_down(void *_param) |
1da177e4 | 836 | { |
4baa0afc TG |
837 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
838 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 839 | int err, cpu = smp_processor_id(); |
724a8688 | 840 | int ret; |
1da177e4 | 841 | |
1da177e4 LT |
842 | /* Ensure this CPU doesn't handle any more interrupts. */ |
843 | err = __cpu_disable(); | |
844 | if (err < 0) | |
f3705136 | 845 | return err; |
1da177e4 | 846 | |
a724632c TG |
847 | /* |
848 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
849 | * do this step again. | |
850 | */ | |
851 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
852 | st->state--; | |
4baa0afc | 853 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
854 | for (; st->state > target; st->state--) { |
855 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
856 | /* | |
857 | * DYING must not fail! | |
858 | */ | |
859 | WARN_ON_ONCE(ret); | |
860 | } | |
4baa0afc | 861 | |
52c063d1 TG |
862 | /* Give up timekeeping duties */ |
863 | tick_handover_do_timer(); | |
1b72d432 TG |
864 | /* Remove CPU from timer broadcasting */ |
865 | tick_offline_cpu(cpu); | |
14e568e7 | 866 | /* Park the stopper thread */ |
090e77c3 | 867 | stop_machine_park(cpu); |
f3705136 | 868 | return 0; |
1da177e4 LT |
869 | } |
870 | ||
98458172 | 871 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 872 | { |
e69aab13 | 873 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 874 | int err; |
1da177e4 | 875 | |
2a58c527 | 876 | /* Park the smpboot threads */ |
1cf4f629 TG |
877 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
878 | ||
6acce3ef | 879 | /* |
a8994181 TG |
880 | * Prevent irq alloc/free while the dying cpu reorganizes the |
881 | * interrupt affinities. | |
6acce3ef | 882 | */ |
a8994181 | 883 | irq_lock_sparse(); |
6acce3ef | 884 | |
a8994181 TG |
885 | /* |
886 | * So now all preempt/rcu users must observe !cpu_active(). | |
887 | */ | |
210e2133 | 888 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 889 | if (err) { |
3b9d6da6 | 890 | /* CPU refused to die */ |
a8994181 | 891 | irq_unlock_sparse(); |
3b9d6da6 SAS |
892 | /* Unpark the hotplug thread so we can rollback there */ |
893 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 894 | return err; |
8fa1d7d3 | 895 | } |
04321587 | 896 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 897 | |
48c5ccae | 898 | /* |
5b1ead68 BJ |
899 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
900 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 901 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
902 | * |
903 | * Wait for the stop thread to go away. | |
48c5ccae | 904 | */ |
5ebe7742 | 905 | wait_for_ap_thread(st, false); |
e69aab13 | 906 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 907 | |
a8994181 TG |
908 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
909 | irq_unlock_sparse(); | |
910 | ||
345527b1 | 911 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
912 | /* This actually kills the CPU. */ |
913 | __cpu_die(cpu); | |
914 | ||
a49b116d | 915 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 916 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
917 | return 0; |
918 | } | |
1da177e4 | 919 | |
71f87b2f TG |
920 | static void cpuhp_complete_idle_dead(void *arg) |
921 | { | |
922 | struct cpuhp_cpu_state *st = arg; | |
923 | ||
5ebe7742 | 924 | complete_ap_thread(st, false); |
71f87b2f TG |
925 | } |
926 | ||
e69aab13 TG |
927 | void cpuhp_report_idle_dead(void) |
928 | { | |
929 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
930 | ||
931 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 932 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
933 | st->state = CPUHP_AP_IDLE_DEAD; |
934 | /* | |
935 | * We cannot call complete after rcu_report_dead() so we delegate it | |
936 | * to an online cpu. | |
937 | */ | |
938 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
939 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
940 | } |
941 | ||
4dddfb5f PZ |
942 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
943 | { | |
6fb86d97 MO |
944 | for (st->state++; st->state < st->target; st->state++) |
945 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
4dddfb5f PZ |
946 | } |
947 | ||
948 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
949 | enum cpuhp_state target) | |
950 | { | |
951 | enum cpuhp_state prev_state = st->state; | |
952 | int ret = 0; | |
953 | ||
954 | for (; st->state > target; st->state--) { | |
955 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
956 | if (ret) { | |
957 | st->target = prev_state; | |
69fa6eb7 TG |
958 | if (st->state < prev_state) |
959 | undo_cpu_down(cpu, st); | |
4dddfb5f PZ |
960 | break; |
961 | } | |
962 | } | |
963 | return ret; | |
964 | } | |
cff7d378 | 965 | |
98458172 | 966 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
967 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
968 | enum cpuhp_state target) | |
98458172 | 969 | { |
cff7d378 TG |
970 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
971 | int prev_state, ret = 0; | |
98458172 TG |
972 | |
973 | if (num_online_cpus() == 1) | |
974 | return -EBUSY; | |
975 | ||
757c989b | 976 | if (!cpu_present(cpu)) |
98458172 TG |
977 | return -EINVAL; |
978 | ||
8f553c49 | 979 | cpus_write_lock(); |
98458172 TG |
980 | |
981 | cpuhp_tasks_frozen = tasks_frozen; | |
982 | ||
4dddfb5f | 983 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
984 | /* |
985 | * If the current CPU state is in the range of the AP hotplug thread, | |
986 | * then we need to kick the thread. | |
987 | */ | |
8df3e07e | 988 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 989 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
990 | ret = cpuhp_kick_ap_work(cpu); |
991 | /* | |
992 | * The AP side has done the error rollback already. Just | |
993 | * return the error code.. | |
994 | */ | |
995 | if (ret) | |
996 | goto out; | |
997 | ||
998 | /* | |
999 | * We might have stopped still in the range of the AP hotplug | |
1000 | * thread. Nothing to do anymore. | |
1001 | */ | |
8df3e07e | 1002 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1003 | goto out; |
4dddfb5f PZ |
1004 | |
1005 | st->target = target; | |
1cf4f629 TG |
1006 | } |
1007 | /* | |
8df3e07e | 1008 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1009 | * to do the further cleanups. |
1010 | */ | |
a724632c | 1011 | ret = cpuhp_down_callbacks(cpu, st, target); |
69fa6eb7 | 1012 | if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
1013 | cpuhp_reset_state(st, prev_state); |
1014 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 1015 | } |
98458172 | 1016 | |
1cf4f629 | 1017 | out: |
8f553c49 | 1018 | cpus_write_unlock(); |
941154bd TG |
1019 | /* |
1020 | * Do post unplug cleanup. This is still protected against | |
1021 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1022 | */ | |
1023 | lockup_detector_cleanup(); | |
a74cfffb | 1024 | arch_smt_update(); |
cff7d378 | 1025 | return ret; |
e3920fb4 RW |
1026 | } |
1027 | ||
cc1fe215 TG |
1028 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1029 | { | |
1030 | if (cpu_hotplug_disabled) | |
1031 | return -EBUSY; | |
1032 | return _cpu_down(cpu, 0, target); | |
1033 | } | |
1034 | ||
af1f4045 | 1035 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1036 | { |
9ea09af3 | 1037 | int err; |
e3920fb4 | 1038 | |
d221938c | 1039 | cpu_maps_update_begin(); |
cc1fe215 | 1040 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1041 | cpu_maps_update_done(); |
1da177e4 LT |
1042 | return err; |
1043 | } | |
4dddfb5f | 1044 | |
af1f4045 TG |
1045 | int cpu_down(unsigned int cpu) |
1046 | { | |
1047 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1048 | } | |
b62b8ef9 | 1049 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f PZ |
1050 | |
1051 | #else | |
1052 | #define takedown_cpu NULL | |
1da177e4 LT |
1053 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1054 | ||
4baa0afc | 1055 | /** |
ee1e714b | 1056 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1057 | * @cpu: cpu that just started |
1058 | * | |
4baa0afc TG |
1059 | * It must be called by the arch code on the new cpu, before the new cpu |
1060 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1061 | */ | |
1062 | void notify_cpu_starting(unsigned int cpu) | |
1063 | { | |
1064 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1065 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1066 | int ret; |
4baa0afc | 1067 | |
0c6d4576 | 1068 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
0cc3cd21 | 1069 | st->booted_once = true; |
4baa0afc | 1070 | while (st->state < target) { |
4baa0afc | 1071 | st->state++; |
724a8688 PZ |
1072 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1073 | /* | |
1074 | * STARTING must not fail! | |
1075 | */ | |
1076 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1077 | } |
1078 | } | |
1079 | ||
949338e3 | 1080 | /* |
9cd4f1a4 TG |
1081 | * Called from the idle task. Wake up the controlling task which brings the |
1082 | * stopper and the hotplug thread of the upcoming CPU up and then delegates | |
1083 | * the rest of the online bringup to the hotplug thread. | |
949338e3 | 1084 | */ |
8df3e07e | 1085 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1086 | { |
8df3e07e | 1087 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1088 | |
1089 | /* Happens for the boot cpu */ | |
1090 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1091 | return; | |
1092 | ||
1093 | st->state = CPUHP_AP_ONLINE_IDLE; | |
5ebe7742 | 1094 | complete_ap_thread(st, true); |
949338e3 TG |
1095 | } |
1096 | ||
e3920fb4 | 1097 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1098 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1099 | { |
cff7d378 | 1100 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1101 | struct task_struct *idle; |
2e1a3483 | 1102 | int ret = 0; |
1da177e4 | 1103 | |
8f553c49 | 1104 | cpus_write_lock(); |
38498a67 | 1105 | |
757c989b | 1106 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1107 | ret = -EINVAL; |
1108 | goto out; | |
1109 | } | |
1110 | ||
757c989b TG |
1111 | /* |
1112 | * The caller of do_cpu_up might have raced with another | |
1113 | * caller. Ignore it for now. | |
1114 | */ | |
1115 | if (st->state >= target) | |
38498a67 | 1116 | goto out; |
757c989b TG |
1117 | |
1118 | if (st->state == CPUHP_OFFLINE) { | |
1119 | /* Let it fail before we try to bring the cpu up */ | |
1120 | idle = idle_thread_get(cpu); | |
1121 | if (IS_ERR(idle)) { | |
1122 | ret = PTR_ERR(idle); | |
1123 | goto out; | |
1124 | } | |
3bb5d2ee | 1125 | } |
38498a67 | 1126 | |
ba997462 TG |
1127 | cpuhp_tasks_frozen = tasks_frozen; |
1128 | ||
4dddfb5f | 1129 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1130 | /* |
1131 | * If the current CPU state is in the range of the AP hotplug thread, | |
1132 | * then we need to kick the thread once more. | |
1133 | */ | |
8df3e07e | 1134 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1135 | ret = cpuhp_kick_ap_work(cpu); |
1136 | /* | |
1137 | * The AP side has done the error rollback already. Just | |
1138 | * return the error code.. | |
1139 | */ | |
1140 | if (ret) | |
1141 | goto out; | |
1142 | } | |
1143 | ||
1144 | /* | |
1145 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1146 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1147 | * responsible for bringing it up to the target state. |
1148 | */ | |
8df3e07e | 1149 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1150 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1151 | out: |
8f553c49 | 1152 | cpus_write_unlock(); |
a74cfffb | 1153 | arch_smt_update(); |
e3920fb4 RW |
1154 | return ret; |
1155 | } | |
1156 | ||
af1f4045 | 1157 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1158 | { |
1159 | int err = 0; | |
cf23422b | 1160 | |
e0b582ec | 1161 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1162 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1163 | cpu); | |
87d5e023 | 1164 | #if defined(CONFIG_IA64) |
84117da5 | 1165 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1166 | #endif |
1167 | return -EINVAL; | |
1168 | } | |
e3920fb4 | 1169 | |
01b0f197 TK |
1170 | err = try_online_node(cpu_to_node(cpu)); |
1171 | if (err) | |
1172 | return err; | |
cf23422b | 1173 | |
d221938c | 1174 | cpu_maps_update_begin(); |
e761b772 MK |
1175 | |
1176 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1177 | err = -EBUSY; |
e761b772 MK |
1178 | goto out; |
1179 | } | |
05736e4a TG |
1180 | if (!cpu_smt_allowed(cpu)) { |
1181 | err = -EPERM; | |
1182 | goto out; | |
1183 | } | |
e761b772 | 1184 | |
af1f4045 | 1185 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1186 | out: |
d221938c | 1187 | cpu_maps_update_done(); |
e3920fb4 RW |
1188 | return err; |
1189 | } | |
af1f4045 TG |
1190 | |
1191 | int cpu_up(unsigned int cpu) | |
1192 | { | |
1193 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1194 | } | |
a513f6ba | 1195 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1196 | |
f3de4be9 | 1197 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1198 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1199 | |
d391e552 | 1200 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1201 | { |
d391e552 | 1202 | int cpu, error = 0; |
e3920fb4 | 1203 | |
d221938c | 1204 | cpu_maps_update_begin(); |
9ca12ac0 | 1205 | if (primary == -1) { |
d391e552 | 1206 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1207 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1208 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1209 | } else { | |
1210 | if (!cpu_online(primary)) | |
1211 | primary = cpumask_first(cpu_online_mask); | |
1212 | } | |
1213 | ||
9ee349ad XF |
1214 | /* |
1215 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1216 | * with the userspace trying to use the CPU hotplug at the same time |
1217 | */ | |
e0b582ec | 1218 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1219 | |
84117da5 | 1220 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1221 | for_each_online_cpu(cpu) { |
d391e552 | 1222 | if (cpu == primary) |
e3920fb4 | 1223 | continue; |
a66d955e PK |
1224 | |
1225 | if (pm_wakeup_pending()) { | |
1226 | pr_info("Wakeup pending. Abort CPU freeze\n"); | |
1227 | error = -EBUSY; | |
1228 | break; | |
1229 | } | |
1230 | ||
bb3632c6 | 1231 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1232 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1233 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1234 | if (!error) |
e0b582ec | 1235 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1236 | else { |
84117da5 | 1237 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1238 | break; |
1239 | } | |
1240 | } | |
86886e55 | 1241 | |
89af7ba5 | 1242 | if (!error) |
e3920fb4 | 1243 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1244 | else |
84117da5 | 1245 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1246 | |
1247 | /* | |
1248 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1249 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1250 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1251 | */ | |
1252 | cpu_hotplug_disabled++; | |
1253 | ||
d221938c | 1254 | cpu_maps_update_done(); |
e3920fb4 RW |
1255 | return error; |
1256 | } | |
1257 | ||
d0af9eed SS |
1258 | void __weak arch_enable_nonboot_cpus_begin(void) |
1259 | { | |
1260 | } | |
1261 | ||
1262 | void __weak arch_enable_nonboot_cpus_end(void) | |
1263 | { | |
1264 | } | |
1265 | ||
71cf5aee | 1266 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1267 | { |
1268 | int cpu, error; | |
1269 | ||
1270 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1271 | cpu_maps_update_begin(); |
01b41159 | 1272 | __cpu_hotplug_enable(); |
e0b582ec | 1273 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1274 | goto out; |
e3920fb4 | 1275 | |
84117da5 | 1276 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1277 | |
1278 | arch_enable_nonboot_cpus_begin(); | |
1279 | ||
e0b582ec | 1280 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1281 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1282 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1283 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1284 | if (!error) { |
84117da5 | 1285 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1286 | continue; |
1287 | } | |
84117da5 | 1288 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1289 | } |
d0af9eed SS |
1290 | |
1291 | arch_enable_nonboot_cpus_end(); | |
1292 | ||
e0b582ec | 1293 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1294 | out: |
d221938c | 1295 | cpu_maps_update_done(); |
1da177e4 | 1296 | } |
e0b582ec | 1297 | |
d7268a31 | 1298 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1299 | { |
1300 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1301 | return -ENOMEM; | |
1302 | return 0; | |
1303 | } | |
1304 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1305 | |
79cfbdfa SB |
1306 | /* |
1307 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1308 | * ensure that the state of the system with respect to the tasks being frozen | |
1309 | * or not, as reported by the notification, remains unchanged *throughout the | |
1310 | * duration* of the execution of the callbacks. | |
1311 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1312 | * | |
1313 | * This synchronization is implemented by mutually excluding regular CPU | |
1314 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1315 | * Hibernate notifications. | |
1316 | */ | |
1317 | static int | |
1318 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1319 | unsigned long action, void *ptr) | |
1320 | { | |
1321 | switch (action) { | |
1322 | ||
1323 | case PM_SUSPEND_PREPARE: | |
1324 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1325 | cpu_hotplug_disable(); |
79cfbdfa SB |
1326 | break; |
1327 | ||
1328 | case PM_POST_SUSPEND: | |
1329 | case PM_POST_HIBERNATION: | |
16e53dbf | 1330 | cpu_hotplug_enable(); |
79cfbdfa SB |
1331 | break; |
1332 | ||
1333 | default: | |
1334 | return NOTIFY_DONE; | |
1335 | } | |
1336 | ||
1337 | return NOTIFY_OK; | |
1338 | } | |
1339 | ||
1340 | ||
d7268a31 | 1341 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1342 | { |
6e32d479 FY |
1343 | /* |
1344 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1345 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1346 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1347 | */ | |
79cfbdfa SB |
1348 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1349 | return 0; | |
1350 | } | |
1351 | core_initcall(cpu_hotplug_pm_sync_init); | |
1352 | ||
f3de4be9 | 1353 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1354 | |
8ce371f9 PZ |
1355 | int __boot_cpu_id; |
1356 | ||
68f4f1ec | 1357 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1358 | |
cff7d378 | 1359 | /* Boot processor state steps */ |
17a2f1ce | 1360 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1361 | [CPUHP_OFFLINE] = { |
1362 | .name = "offline", | |
3c1627e9 TG |
1363 | .startup.single = NULL, |
1364 | .teardown.single = NULL, | |
cff7d378 TG |
1365 | }, |
1366 | #ifdef CONFIG_SMP | |
1367 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1368 | .name = "threads:prepare", |
3c1627e9 TG |
1369 | .startup.single = smpboot_create_threads, |
1370 | .teardown.single = NULL, | |
757c989b | 1371 | .cant_stop = true, |
cff7d378 | 1372 | }, |
00e16c3d | 1373 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1374 | .name = "perf:prepare", |
1375 | .startup.single = perf_event_init_cpu, | |
1376 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1377 | }, |
7ee681b2 | 1378 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1379 | .name = "workqueue:prepare", |
1380 | .startup.single = workqueue_prepare_cpu, | |
1381 | .teardown.single = NULL, | |
7ee681b2 | 1382 | }, |
27590dc1 | 1383 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1384 | .name = "hrtimers:prepare", |
1385 | .startup.single = hrtimers_prepare_cpu, | |
1386 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1387 | }, |
31487f83 | 1388 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1389 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1390 | .startup.single = smpcfd_prepare_cpu, |
1391 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1392 | }, |
e6d4989a RW |
1393 | [CPUHP_RELAY_PREPARE] = { |
1394 | .name = "relay:prepare", | |
1395 | .startup.single = relay_prepare_cpu, | |
1396 | .teardown.single = NULL, | |
1397 | }, | |
6731d4f1 SAS |
1398 | [CPUHP_SLAB_PREPARE] = { |
1399 | .name = "slab:prepare", | |
1400 | .startup.single = slab_prepare_cpu, | |
1401 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1402 | }, |
4df83742 | 1403 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1404 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1405 | .startup.single = rcutree_prepare_cpu, |
1406 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1407 | }, |
4fae16df RC |
1408 | /* |
1409 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1410 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1411 | * otherwise a RCU stall occurs. | |
1412 | */ | |
26456f87 | 1413 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1414 | .name = "timers:prepare", |
26456f87 | 1415 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1416 | .teardown.single = timers_dead_cpu, |
4fae16df | 1417 | }, |
d10ef6f9 | 1418 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1419 | [CPUHP_BRINGUP_CPU] = { |
1420 | .name = "cpu:bringup", | |
3c1627e9 TG |
1421 | .startup.single = bringup_cpu, |
1422 | .teardown.single = NULL, | |
757c989b | 1423 | .cant_stop = true, |
4baa0afc | 1424 | }, |
d10ef6f9 TG |
1425 | /* Final state before CPU kills itself */ |
1426 | [CPUHP_AP_IDLE_DEAD] = { | |
1427 | .name = "idle:dead", | |
1428 | }, | |
1429 | /* | |
1430 | * Last state before CPU enters the idle loop to die. Transient state | |
1431 | * for synchronization. | |
1432 | */ | |
1433 | [CPUHP_AP_OFFLINE] = { | |
1434 | .name = "ap:offline", | |
1435 | .cant_stop = true, | |
1436 | }, | |
9cf7243d TG |
1437 | /* First state is scheduler control. Interrupts are disabled */ |
1438 | [CPUHP_AP_SCHED_STARTING] = { | |
1439 | .name = "sched:starting", | |
3c1627e9 TG |
1440 | .startup.single = sched_cpu_starting, |
1441 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1442 | }, |
4df83742 | 1443 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1444 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1445 | .startup.single = NULL, |
1446 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1447 | }, |
46febd37 LJ |
1448 | [CPUHP_AP_SMPCFD_DYING] = { |
1449 | .name = "smpcfd:dying", | |
1450 | .startup.single = NULL, | |
1451 | .teardown.single = smpcfd_dying_cpu, | |
1452 | }, | |
d10ef6f9 TG |
1453 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1454 | * state for synchronsization */ | |
1455 | [CPUHP_AP_ONLINE] = { | |
1456 | .name = "ap:online", | |
1457 | }, | |
17a2f1ce LJ |
1458 | /* |
1459 | * Handled on controll processor until the plugged processor manages | |
1460 | * this itself. | |
1461 | */ | |
1462 | [CPUHP_TEARDOWN_CPU] = { | |
1463 | .name = "cpu:teardown", | |
1464 | .startup.single = NULL, | |
1465 | .teardown.single = takedown_cpu, | |
1466 | .cant_stop = true, | |
1467 | }, | |
d10ef6f9 | 1468 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1469 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1470 | .name = "smpboot/threads:online", |
3c1627e9 | 1471 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1472 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1473 | }, |
c5cb83bb TG |
1474 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1475 | .name = "irq/affinity:online", | |
1476 | .startup.single = irq_affinity_online_cpu, | |
1477 | .teardown.single = NULL, | |
1478 | }, | |
00e16c3d | 1479 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1480 | .name = "perf:online", |
1481 | .startup.single = perf_event_init_cpu, | |
1482 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1483 | }, |
9cf57731 PZ |
1484 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1485 | .name = "lockup_detector:online", | |
1486 | .startup.single = lockup_detector_online_cpu, | |
1487 | .teardown.single = lockup_detector_offline_cpu, | |
1488 | }, | |
7ee681b2 | 1489 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1490 | .name = "workqueue:online", |
1491 | .startup.single = workqueue_online_cpu, | |
1492 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1493 | }, |
4df83742 | 1494 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1495 | .name = "RCU/tree:online", |
3c1627e9 TG |
1496 | .startup.single = rcutree_online_cpu, |
1497 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1498 | }, |
4baa0afc | 1499 | #endif |
d10ef6f9 TG |
1500 | /* |
1501 | * The dynamically registered state space is here | |
1502 | */ | |
1503 | ||
aaddd7d1 TG |
1504 | #ifdef CONFIG_SMP |
1505 | /* Last state is scheduler control setting the cpu active */ | |
1506 | [CPUHP_AP_ACTIVE] = { | |
1507 | .name = "sched:active", | |
3c1627e9 TG |
1508 | .startup.single = sched_cpu_activate, |
1509 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1510 | }, |
1511 | #endif | |
1512 | ||
d10ef6f9 | 1513 | /* CPU is fully up and running. */ |
4baa0afc TG |
1514 | [CPUHP_ONLINE] = { |
1515 | .name = "online", | |
3c1627e9 TG |
1516 | .startup.single = NULL, |
1517 | .teardown.single = NULL, | |
4baa0afc TG |
1518 | }, |
1519 | }; | |
1520 | ||
5b7aa87e TG |
1521 | /* Sanity check for callbacks */ |
1522 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1523 | { | |
1524 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1525 | return -EINVAL; | |
1526 | return 0; | |
1527 | } | |
1528 | ||
dc280d93 TG |
1529 | /* |
1530 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1531 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1532 | * by having no name assigned. | |
1533 | */ | |
1534 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1535 | { | |
4205e478 TG |
1536 | enum cpuhp_state i, end; |
1537 | struct cpuhp_step *step; | |
dc280d93 | 1538 | |
4205e478 TG |
1539 | switch (state) { |
1540 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1541 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1542 | end = CPUHP_AP_ONLINE_DYN_END; |
1543 | break; | |
1544 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1545 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1546 | end = CPUHP_BP_PREPARE_DYN_END; |
1547 | break; | |
1548 | default: | |
1549 | return -EINVAL; | |
1550 | } | |
1551 | ||
1552 | for (i = state; i <= end; i++, step++) { | |
1553 | if (!step->name) | |
dc280d93 TG |
1554 | return i; |
1555 | } | |
1556 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1557 | return -ENOSPC; | |
1558 | } | |
1559 | ||
1560 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1561 | int (*startup)(unsigned int cpu), | |
1562 | int (*teardown)(unsigned int cpu), | |
1563 | bool multi_instance) | |
5b7aa87e TG |
1564 | { |
1565 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1566 | struct cpuhp_step *sp; | |
dc280d93 | 1567 | int ret = 0; |
5b7aa87e | 1568 | |
0c96b273 EB |
1569 | /* |
1570 | * If name is NULL, then the state gets removed. | |
1571 | * | |
1572 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1573 | * the first allocation from these dynamic ranges, so the removal | |
1574 | * would trigger a new allocation and clear the wrong (already | |
1575 | * empty) state, leaving the callbacks of the to be cleared state | |
1576 | * dangling, which causes wreckage on the next hotplug operation. | |
1577 | */ | |
1578 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1579 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1580 | ret = cpuhp_reserve_state(state); |
1581 | if (ret < 0) | |
dc434e05 | 1582 | return ret; |
dc280d93 TG |
1583 | state = ret; |
1584 | } | |
5b7aa87e | 1585 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1586 | if (name && sp->name) |
1587 | return -EBUSY; | |
1588 | ||
3c1627e9 TG |
1589 | sp->startup.single = startup; |
1590 | sp->teardown.single = teardown; | |
5b7aa87e | 1591 | sp->name = name; |
cf392d10 TG |
1592 | sp->multi_instance = multi_instance; |
1593 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1594 | return ret; |
5b7aa87e TG |
1595 | } |
1596 | ||
1597 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1598 | { | |
3c1627e9 | 1599 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1600 | } |
1601 | ||
5b7aa87e TG |
1602 | /* |
1603 | * Call the startup/teardown function for a step either on the AP or | |
1604 | * on the current CPU. | |
1605 | */ | |
cf392d10 TG |
1606 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1607 | struct hlist_node *node) | |
5b7aa87e | 1608 | { |
a724632c | 1609 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1610 | int ret; |
1611 | ||
4dddfb5f PZ |
1612 | /* |
1613 | * If there's nothing to do, we done. | |
1614 | * Relies on the union for multi_instance. | |
1615 | */ | |
3c1627e9 TG |
1616 | if ((bringup && !sp->startup.single) || |
1617 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1618 | return 0; |
5b7aa87e TG |
1619 | /* |
1620 | * The non AP bound callbacks can fail on bringup. On teardown | |
1621 | * e.g. module removal we crash for now. | |
1622 | */ | |
1cf4f629 TG |
1623 | #ifdef CONFIG_SMP |
1624 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1625 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1626 | else |
96abb968 | 1627 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1628 | #else |
96abb968 | 1629 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1630 | #endif |
5b7aa87e TG |
1631 | BUG_ON(ret && !bringup); |
1632 | return ret; | |
1633 | } | |
1634 | ||
1635 | /* | |
1636 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1637 | * | |
1638 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1639 | */ | |
1640 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1641 | struct hlist_node *node) |
5b7aa87e TG |
1642 | { |
1643 | int cpu; | |
1644 | ||
5b7aa87e TG |
1645 | /* Roll back the already executed steps on the other cpus */ |
1646 | for_each_present_cpu(cpu) { | |
1647 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1648 | int cpustate = st->state; | |
1649 | ||
1650 | if (cpu >= failedcpu) | |
1651 | break; | |
1652 | ||
1653 | /* Did we invoke the startup call on that cpu ? */ | |
1654 | if (cpustate >= state) | |
cf392d10 | 1655 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1656 | } |
1657 | } | |
1658 | ||
9805c673 TG |
1659 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1660 | struct hlist_node *node, | |
1661 | bool invoke) | |
cf392d10 TG |
1662 | { |
1663 | struct cpuhp_step *sp; | |
1664 | int cpu; | |
1665 | int ret; | |
1666 | ||
9805c673 TG |
1667 | lockdep_assert_cpus_held(); |
1668 | ||
cf392d10 TG |
1669 | sp = cpuhp_get_step(state); |
1670 | if (sp->multi_instance == false) | |
1671 | return -EINVAL; | |
1672 | ||
dc434e05 | 1673 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1674 | |
3c1627e9 | 1675 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1676 | goto add_node; |
1677 | ||
1678 | /* | |
1679 | * Try to call the startup callback for each present cpu | |
1680 | * depending on the hotplug state of the cpu. | |
1681 | */ | |
1682 | for_each_present_cpu(cpu) { | |
1683 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1684 | int cpustate = st->state; | |
1685 | ||
1686 | if (cpustate < state) | |
1687 | continue; | |
1688 | ||
1689 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1690 | if (ret) { | |
3c1627e9 | 1691 | if (sp->teardown.multi) |
cf392d10 | 1692 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1693 | goto unlock; |
cf392d10 TG |
1694 | } |
1695 | } | |
1696 | add_node: | |
1697 | ret = 0; | |
cf392d10 | 1698 | hlist_add_head(node, &sp->list); |
dc434e05 | 1699 | unlock: |
cf392d10 | 1700 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1701 | return ret; |
1702 | } | |
1703 | ||
1704 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1705 | bool invoke) | |
1706 | { | |
1707 | int ret; | |
1708 | ||
1709 | cpus_read_lock(); | |
1710 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1711 | cpus_read_unlock(); |
cf392d10 TG |
1712 | return ret; |
1713 | } | |
1714 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1715 | ||
5b7aa87e | 1716 | /** |
71def423 | 1717 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1718 | * @state: The state to setup |
1719 | * @invoke: If true, the startup function is invoked for cpus where | |
1720 | * cpu state >= @state | |
1721 | * @startup: startup callback function | |
1722 | * @teardown: teardown callback function | |
1723 | * @multi_instance: State is set up for multiple instances which get | |
1724 | * added afterwards. | |
5b7aa87e | 1725 | * |
71def423 | 1726 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1727 | * Returns: |
1728 | * On success: | |
1729 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1730 | * 0 for all other states | |
1731 | * On failure: proper (negative) error code | |
5b7aa87e | 1732 | */ |
71def423 SAS |
1733 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1734 | const char *name, bool invoke, | |
1735 | int (*startup)(unsigned int cpu), | |
1736 | int (*teardown)(unsigned int cpu), | |
1737 | bool multi_instance) | |
5b7aa87e TG |
1738 | { |
1739 | int cpu, ret = 0; | |
b9d9d691 | 1740 | bool dynstate; |
5b7aa87e | 1741 | |
71def423 SAS |
1742 | lockdep_assert_cpus_held(); |
1743 | ||
5b7aa87e TG |
1744 | if (cpuhp_cb_check(state) || !name) |
1745 | return -EINVAL; | |
1746 | ||
dc434e05 | 1747 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1748 | |
dc280d93 TG |
1749 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1750 | multi_instance); | |
5b7aa87e | 1751 | |
b9d9d691 TG |
1752 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1753 | if (ret > 0 && dynstate) { | |
1754 | state = ret; | |
1755 | ret = 0; | |
1756 | } | |
1757 | ||
dc280d93 | 1758 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1759 | goto out; |
1760 | ||
1761 | /* | |
1762 | * Try to call the startup callback for each present cpu | |
1763 | * depending on the hotplug state of the cpu. | |
1764 | */ | |
1765 | for_each_present_cpu(cpu) { | |
1766 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1767 | int cpustate = st->state; | |
1768 | ||
1769 | if (cpustate < state) | |
1770 | continue; | |
1771 | ||
cf392d10 | 1772 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1773 | if (ret) { |
a724632c | 1774 | if (teardown) |
cf392d10 TG |
1775 | cpuhp_rollback_install(cpu, state, NULL); |
1776 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1777 | goto out; |
1778 | } | |
1779 | } | |
1780 | out: | |
dc434e05 | 1781 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1782 | /* |
1783 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1784 | * dynamically allocated state in case of success. | |
1785 | */ | |
b9d9d691 | 1786 | if (!ret && dynstate) |
5b7aa87e TG |
1787 | return state; |
1788 | return ret; | |
1789 | } | |
71def423 SAS |
1790 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1791 | ||
1792 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1793 | const char *name, bool invoke, | |
1794 | int (*startup)(unsigned int cpu), | |
1795 | int (*teardown)(unsigned int cpu), | |
1796 | bool multi_instance) | |
1797 | { | |
1798 | int ret; | |
1799 | ||
1800 | cpus_read_lock(); | |
1801 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1802 | teardown, multi_instance); | |
1803 | cpus_read_unlock(); | |
1804 | return ret; | |
1805 | } | |
5b7aa87e TG |
1806 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1807 | ||
cf392d10 TG |
1808 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1809 | struct hlist_node *node, bool invoke) | |
1810 | { | |
1811 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1812 | int cpu; | |
1813 | ||
1814 | BUG_ON(cpuhp_cb_check(state)); | |
1815 | ||
1816 | if (!sp->multi_instance) | |
1817 | return -EINVAL; | |
1818 | ||
8f553c49 | 1819 | cpus_read_lock(); |
dc434e05 SAS |
1820 | mutex_lock(&cpuhp_state_mutex); |
1821 | ||
cf392d10 TG |
1822 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1823 | goto remove; | |
1824 | /* | |
1825 | * Call the teardown callback for each present cpu depending | |
1826 | * on the hotplug state of the cpu. This function is not | |
1827 | * allowed to fail currently! | |
1828 | */ | |
1829 | for_each_present_cpu(cpu) { | |
1830 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1831 | int cpustate = st->state; | |
1832 | ||
1833 | if (cpustate >= state) | |
1834 | cpuhp_issue_call(cpu, state, false, node); | |
1835 | } | |
1836 | ||
1837 | remove: | |
cf392d10 TG |
1838 | hlist_del(node); |
1839 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1840 | cpus_read_unlock(); |
cf392d10 TG |
1841 | |
1842 | return 0; | |
1843 | } | |
1844 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1845 | |
5b7aa87e | 1846 | /** |
71def423 | 1847 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1848 | * @state: The state to remove |
1849 | * @invoke: If true, the teardown function is invoked for cpus where | |
1850 | * cpu state >= @state | |
1851 | * | |
71def423 | 1852 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1853 | * The teardown callback is currently not allowed to fail. Think |
1854 | * about module removal! | |
1855 | */ | |
71def423 | 1856 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1857 | { |
cf392d10 | 1858 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1859 | int cpu; |
1860 | ||
1861 | BUG_ON(cpuhp_cb_check(state)); | |
1862 | ||
71def423 | 1863 | lockdep_assert_cpus_held(); |
5b7aa87e | 1864 | |
dc434e05 | 1865 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1866 | if (sp->multi_instance) { |
1867 | WARN(!hlist_empty(&sp->list), | |
1868 | "Error: Removing state %d which has instances left.\n", | |
1869 | state); | |
1870 | goto remove; | |
1871 | } | |
1872 | ||
a724632c | 1873 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1874 | goto remove; |
1875 | ||
1876 | /* | |
1877 | * Call the teardown callback for each present cpu depending | |
1878 | * on the hotplug state of the cpu. This function is not | |
1879 | * allowed to fail currently! | |
1880 | */ | |
1881 | for_each_present_cpu(cpu) { | |
1882 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1883 | int cpustate = st->state; | |
1884 | ||
1885 | if (cpustate >= state) | |
cf392d10 | 1886 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1887 | } |
1888 | remove: | |
cf392d10 | 1889 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1890 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1891 | } |
1892 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1893 | ||
1894 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1895 | { | |
1896 | cpus_read_lock(); | |
1897 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 1898 | cpus_read_unlock(); |
5b7aa87e TG |
1899 | } |
1900 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1901 | ||
98f8cdce TG |
1902 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1903 | static ssize_t show_cpuhp_state(struct device *dev, | |
1904 | struct device_attribute *attr, char *buf) | |
1905 | { | |
1906 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1907 | ||
1908 | return sprintf(buf, "%d\n", st->state); | |
1909 | } | |
1910 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1911 | ||
757c989b TG |
1912 | static ssize_t write_cpuhp_target(struct device *dev, |
1913 | struct device_attribute *attr, | |
1914 | const char *buf, size_t count) | |
1915 | { | |
1916 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1917 | struct cpuhp_step *sp; | |
1918 | int target, ret; | |
1919 | ||
1920 | ret = kstrtoint(buf, 10, &target); | |
1921 | if (ret) | |
1922 | return ret; | |
1923 | ||
1924 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1925 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1926 | return -EINVAL; | |
1927 | #else | |
1928 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1929 | return -EINVAL; | |
1930 | #endif | |
1931 | ||
1932 | ret = lock_device_hotplug_sysfs(); | |
1933 | if (ret) | |
1934 | return ret; | |
1935 | ||
1936 | mutex_lock(&cpuhp_state_mutex); | |
1937 | sp = cpuhp_get_step(target); | |
1938 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1939 | mutex_unlock(&cpuhp_state_mutex); | |
1940 | if (ret) | |
40da1b11 | 1941 | goto out; |
757c989b TG |
1942 | |
1943 | if (st->state < target) | |
1944 | ret = do_cpu_up(dev->id, target); | |
1945 | else | |
1946 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 1947 | out: |
757c989b TG |
1948 | unlock_device_hotplug(); |
1949 | return ret ? ret : count; | |
1950 | } | |
1951 | ||
98f8cdce TG |
1952 | static ssize_t show_cpuhp_target(struct device *dev, |
1953 | struct device_attribute *attr, char *buf) | |
1954 | { | |
1955 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1956 | ||
1957 | return sprintf(buf, "%d\n", st->target); | |
1958 | } | |
757c989b | 1959 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 1960 | |
1db49484 PZ |
1961 | |
1962 | static ssize_t write_cpuhp_fail(struct device *dev, | |
1963 | struct device_attribute *attr, | |
1964 | const char *buf, size_t count) | |
1965 | { | |
1966 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1967 | struct cpuhp_step *sp; | |
1968 | int fail, ret; | |
1969 | ||
1970 | ret = kstrtoint(buf, 10, &fail); | |
1971 | if (ret) | |
1972 | return ret; | |
1973 | ||
33d4a5a7 ET |
1974 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
1975 | return -EINVAL; | |
1976 | ||
1db49484 PZ |
1977 | /* |
1978 | * Cannot fail STARTING/DYING callbacks. | |
1979 | */ | |
1980 | if (cpuhp_is_atomic_state(fail)) | |
1981 | return -EINVAL; | |
1982 | ||
1983 | /* | |
1984 | * Cannot fail anything that doesn't have callbacks. | |
1985 | */ | |
1986 | mutex_lock(&cpuhp_state_mutex); | |
1987 | sp = cpuhp_get_step(fail); | |
1988 | if (!sp->startup.single && !sp->teardown.single) | |
1989 | ret = -EINVAL; | |
1990 | mutex_unlock(&cpuhp_state_mutex); | |
1991 | if (ret) | |
1992 | return ret; | |
1993 | ||
1994 | st->fail = fail; | |
1995 | ||
1996 | return count; | |
1997 | } | |
1998 | ||
1999 | static ssize_t show_cpuhp_fail(struct device *dev, | |
2000 | struct device_attribute *attr, char *buf) | |
2001 | { | |
2002 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2003 | ||
2004 | return sprintf(buf, "%d\n", st->fail); | |
2005 | } | |
2006 | ||
2007 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
2008 | ||
98f8cdce TG |
2009 | static struct attribute *cpuhp_cpu_attrs[] = { |
2010 | &dev_attr_state.attr, | |
2011 | &dev_attr_target.attr, | |
1db49484 | 2012 | &dev_attr_fail.attr, |
98f8cdce TG |
2013 | NULL |
2014 | }; | |
2015 | ||
993647a2 | 2016 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2017 | .attrs = cpuhp_cpu_attrs, |
2018 | .name = "hotplug", | |
2019 | NULL | |
2020 | }; | |
2021 | ||
2022 | static ssize_t show_cpuhp_states(struct device *dev, | |
2023 | struct device_attribute *attr, char *buf) | |
2024 | { | |
2025 | ssize_t cur, res = 0; | |
2026 | int i; | |
2027 | ||
2028 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2029 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2030 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2031 | ||
2032 | if (sp->name) { | |
2033 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2034 | buf += cur; | |
2035 | res += cur; | |
2036 | } | |
2037 | } | |
2038 | mutex_unlock(&cpuhp_state_mutex); | |
2039 | return res; | |
2040 | } | |
2041 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2042 | ||
2043 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2044 | &dev_attr_states.attr, | |
2045 | NULL | |
2046 | }; | |
2047 | ||
993647a2 | 2048 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2049 | .attrs = cpuhp_cpu_root_attrs, |
2050 | .name = "hotplug", | |
2051 | NULL | |
2052 | }; | |
2053 | ||
05736e4a TG |
2054 | #ifdef CONFIG_HOTPLUG_SMT |
2055 | ||
05736e4a TG |
2056 | static void cpuhp_offline_cpu_device(unsigned int cpu) |
2057 | { | |
2058 | struct device *dev = get_cpu_device(cpu); | |
2059 | ||
2060 | dev->offline = true; | |
2061 | /* Tell user space about the state change */ | |
2062 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2063 | } | |
2064 | ||
215af549 TG |
2065 | static void cpuhp_online_cpu_device(unsigned int cpu) |
2066 | { | |
2067 | struct device *dev = get_cpu_device(cpu); | |
2068 | ||
2069 | dev->offline = false; | |
2070 | /* Tell user space about the state change */ | |
2071 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2072 | } | |
2073 | ||
ec527c31 | 2074 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) |
05736e4a TG |
2075 | { |
2076 | int cpu, ret = 0; | |
2077 | ||
2078 | cpu_maps_update_begin(); | |
2079 | for_each_online_cpu(cpu) { | |
2080 | if (topology_is_primary_thread(cpu)) | |
2081 | continue; | |
2082 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2083 | if (ret) | |
2084 | break; | |
2085 | /* | |
2086 | * As this needs to hold the cpu maps lock it's impossible | |
2087 | * to call device_offline() because that ends up calling | |
2088 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2089 | * needs to be held as this might race against in kernel | |
2090 | * abusers of the hotplug machinery (thermal management). | |
2091 | * | |
2092 | * So nothing would update device:offline state. That would | |
2093 | * leave the sysfs entry stale and prevent onlining after | |
2094 | * smt control has been changed to 'off' again. This is | |
2095 | * called under the sysfs hotplug lock, so it is properly | |
2096 | * serialized against the regular offline usage. | |
2097 | */ | |
2098 | cpuhp_offline_cpu_device(cpu); | |
2099 | } | |
34d66caf | 2100 | if (!ret) |
05736e4a TG |
2101 | cpu_smt_control = ctrlval; |
2102 | cpu_maps_update_done(); | |
2103 | return ret; | |
2104 | } | |
2105 | ||
ec527c31 | 2106 | int cpuhp_smt_enable(void) |
05736e4a | 2107 | { |
215af549 TG |
2108 | int cpu, ret = 0; |
2109 | ||
05736e4a TG |
2110 | cpu_maps_update_begin(); |
2111 | cpu_smt_control = CPU_SMT_ENABLED; | |
215af549 TG |
2112 | for_each_present_cpu(cpu) { |
2113 | /* Skip online CPUs and CPUs on offline nodes */ | |
2114 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2115 | continue; | |
2116 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2117 | if (ret) | |
2118 | break; | |
2119 | /* See comment in cpuhp_smt_disable() */ | |
2120 | cpuhp_online_cpu_device(cpu); | |
2121 | } | |
05736e4a | 2122 | cpu_maps_update_done(); |
215af549 | 2123 | return ret; |
05736e4a TG |
2124 | } |
2125 | ||
de7b77e5 | 2126 | |
05736e4a | 2127 | static ssize_t |
de7b77e5 JP |
2128 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2129 | const char *buf, size_t count) | |
05736e4a TG |
2130 | { |
2131 | int ctrlval, ret; | |
2132 | ||
2133 | if (sysfs_streq(buf, "on")) | |
2134 | ctrlval = CPU_SMT_ENABLED; | |
2135 | else if (sysfs_streq(buf, "off")) | |
2136 | ctrlval = CPU_SMT_DISABLED; | |
2137 | else if (sysfs_streq(buf, "forceoff")) | |
2138 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2139 | else | |
2140 | return -EINVAL; | |
2141 | ||
2142 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2143 | return -EPERM; | |
2144 | ||
2145 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2146 | return -ENODEV; | |
2147 | ||
2148 | ret = lock_device_hotplug_sysfs(); | |
2149 | if (ret) | |
2150 | return ret; | |
2151 | ||
2152 | if (ctrlval != cpu_smt_control) { | |
2153 | switch (ctrlval) { | |
2154 | case CPU_SMT_ENABLED: | |
215af549 | 2155 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2156 | break; |
2157 | case CPU_SMT_DISABLED: | |
2158 | case CPU_SMT_FORCE_DISABLED: | |
2159 | ret = cpuhp_smt_disable(ctrlval); | |
2160 | break; | |
2161 | } | |
2162 | } | |
2163 | ||
2164 | unlock_device_hotplug(); | |
2165 | return ret ? ret : count; | |
2166 | } | |
de7b77e5 JP |
2167 | |
2168 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2169 | static ssize_t | |
2170 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2171 | const char *buf, size_t count) | |
2172 | { | |
2173 | return -ENODEV; | |
2174 | } | |
2175 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2176 | ||
2177 | static const char *smt_states[] = { | |
2178 | [CPU_SMT_ENABLED] = "on", | |
2179 | [CPU_SMT_DISABLED] = "off", | |
2180 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2181 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2182 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2183 | }; | |
2184 | ||
2185 | static ssize_t | |
2186 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2187 | { | |
2188 | const char *state = smt_states[cpu_smt_control]; | |
2189 | ||
2190 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2191 | } | |
2192 | ||
2193 | static ssize_t | |
2194 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2195 | const char *buf, size_t count) | |
2196 | { | |
2197 | return __store_smt_control(dev, attr, buf, count); | |
2198 | } | |
05736e4a TG |
2199 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
2200 | ||
2201 | static ssize_t | |
2202 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2203 | { | |
de7b77e5 | 2204 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a TG |
2205 | } |
2206 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2207 | ||
2208 | static struct attribute *cpuhp_smt_attrs[] = { | |
2209 | &dev_attr_control.attr, | |
2210 | &dev_attr_active.attr, | |
2211 | NULL | |
2212 | }; | |
2213 | ||
2214 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2215 | .attrs = cpuhp_smt_attrs, | |
2216 | .name = "smt", | |
2217 | NULL | |
2218 | }; | |
2219 | ||
de7b77e5 | 2220 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2221 | { |
05736e4a TG |
2222 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2223 | &cpuhp_smt_attr_group); | |
2224 | } | |
2225 | ||
98f8cdce TG |
2226 | static int __init cpuhp_sysfs_init(void) |
2227 | { | |
2228 | int cpu, ret; | |
2229 | ||
de7b77e5 | 2230 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2231 | if (ret) |
2232 | return ret; | |
2233 | ||
98f8cdce TG |
2234 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2235 | &cpuhp_cpu_root_attr_group); | |
2236 | if (ret) | |
2237 | return ret; | |
2238 | ||
2239 | for_each_possible_cpu(cpu) { | |
2240 | struct device *dev = get_cpu_device(cpu); | |
2241 | ||
2242 | if (!dev) | |
2243 | continue; | |
2244 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2245 | if (ret) | |
2246 | return ret; | |
2247 | } | |
2248 | return 0; | |
2249 | } | |
2250 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2251 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2252 | |
e56b3bc7 LT |
2253 | /* |
2254 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2255 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2256 | * | |
e0b582ec | 2257 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2258 | * mask value that has a single bit set only. |
2259 | */ | |
b8d317d1 | 2260 | |
e56b3bc7 | 2261 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2262 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2263 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2264 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2265 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2266 | |
e56b3bc7 LT |
2267 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2268 | ||
2269 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2270 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2271 | #if BITS_PER_LONG > 32 | |
2272 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2273 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2274 | #endif |
2275 | }; | |
e56b3bc7 | 2276 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2277 | |
2278 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2279 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2280 | |
2281 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2282 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2283 | = {CPU_BITS_ALL}; |
b3199c02 | 2284 | #else |
4b804c85 | 2285 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2286 | #endif |
4b804c85 | 2287 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2288 | |
4b804c85 RV |
2289 | struct cpumask __cpu_online_mask __read_mostly; |
2290 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2291 | |
4b804c85 RV |
2292 | struct cpumask __cpu_present_mask __read_mostly; |
2293 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2294 | |
4b804c85 RV |
2295 | struct cpumask __cpu_active_mask __read_mostly; |
2296 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2297 | |
3fa41520 RR |
2298 | void init_cpu_present(const struct cpumask *src) |
2299 | { | |
c4c54dd1 | 2300 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2301 | } |
2302 | ||
2303 | void init_cpu_possible(const struct cpumask *src) | |
2304 | { | |
c4c54dd1 | 2305 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2306 | } |
2307 | ||
2308 | void init_cpu_online(const struct cpumask *src) | |
2309 | { | |
c4c54dd1 | 2310 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2311 | } |
cff7d378 TG |
2312 | |
2313 | /* | |
2314 | * Activate the first processor. | |
2315 | */ | |
2316 | void __init boot_cpu_init(void) | |
2317 | { | |
2318 | int cpu = smp_processor_id(); | |
2319 | ||
2320 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2321 | set_cpu_online(cpu, true); | |
2322 | set_cpu_active(cpu, true); | |
2323 | set_cpu_present(cpu, true); | |
2324 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2325 | |
2326 | #ifdef CONFIG_SMP | |
2327 | __boot_cpu_id = cpu; | |
2328 | #endif | |
cff7d378 TG |
2329 | } |
2330 | ||
2331 | /* | |
2332 | * Must be called _AFTER_ setting up the per_cpu areas | |
2333 | */ | |
b5b1404d | 2334 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2335 | { |
269777aa | 2336 | #ifdef CONFIG_SMP |
0cc3cd21 | 2337 | this_cpu_write(cpuhp_state.booted_once, true); |
269777aa | 2338 | #endif |
0cc3cd21 | 2339 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2340 | } |
98af8452 JP |
2341 | |
2342 | enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO; | |
2343 | ||
2344 | static int __init mitigations_parse_cmdline(char *arg) | |
2345 | { | |
2346 | if (!strcmp(arg, "off")) | |
2347 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2348 | else if (!strcmp(arg, "auto")) | |
2349 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2350 | else if (!strcmp(arg, "auto,nosmt")) | |
2351 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2352 | else |
2353 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2354 | arg); | |
98af8452 JP |
2355 | |
2356 | return 0; | |
2357 | } | |
2358 | early_param("mitigations", mitigations_parse_cmdline); |