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 | { | |
339 | rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, 1, _THIS_IP_); | |
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 TG |
527 | |
528 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ | |
529 | stop_machine_unpark(cpu); | |
530 | kthread_unpark(st->thread); | |
531 | ||
0cc3cd21 TG |
532 | /* |
533 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
534 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 535 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
536 | * cpu_smt_allowed() check will now return false if this is not the |
537 | * primary sibling. | |
538 | */ | |
539 | if (!cpu_smt_allowed(cpu)) | |
540 | return -ECANCELED; | |
541 | ||
4dddfb5f PZ |
542 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
543 | return 0; | |
544 | ||
545 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
546 | } |
547 | ||
ba997462 TG |
548 | static int bringup_cpu(unsigned int cpu) |
549 | { | |
550 | struct task_struct *idle = idle_thread_get(cpu); | |
551 | int ret; | |
552 | ||
aa877175 BO |
553 | /* |
554 | * Some architectures have to walk the irq descriptors to | |
555 | * setup the vector space for the cpu which comes online. | |
556 | * Prevent irq alloc/free across the bringup. | |
557 | */ | |
558 | irq_lock_sparse(); | |
559 | ||
ba997462 TG |
560 | /* Arch-specific enabling code. */ |
561 | ret = __cpu_up(cpu, idle); | |
aa877175 | 562 | irq_unlock_sparse(); |
530e9b76 | 563 | if (ret) |
ba997462 | 564 | return ret; |
9cd4f1a4 | 565 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
566 | } |
567 | ||
2e1a3483 TG |
568 | /* |
569 | * Hotplug state machine related functions | |
570 | */ | |
2e1a3483 | 571 | |
a724632c | 572 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 | 573 | { |
6fb86d97 MO |
574 | for (st->state--; st->state > st->target; st->state--) |
575 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
2e1a3483 TG |
576 | } |
577 | ||
206b9235 TG |
578 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
579 | { | |
580 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
581 | return true; | |
582 | /* | |
583 | * When CPU hotplug is disabled, then taking the CPU down is not | |
584 | * possible because takedown_cpu() and the architecture and | |
585 | * subsystem specific mechanisms are not available. So the CPU | |
586 | * which would be completely unplugged again needs to stay around | |
587 | * in the current state. | |
588 | */ | |
589 | return st->state <= CPUHP_BRINGUP_CPU; | |
590 | } | |
591 | ||
2e1a3483 | 592 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 593 | enum cpuhp_state target) |
2e1a3483 TG |
594 | { |
595 | enum cpuhp_state prev_state = st->state; | |
596 | int ret = 0; | |
597 | ||
598 | while (st->state < target) { | |
2e1a3483 | 599 | st->state++; |
96abb968 | 600 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 | 601 | if (ret) { |
206b9235 TG |
602 | if (can_rollback_cpu(st)) { |
603 | st->target = prev_state; | |
604 | undo_cpu_up(cpu, st); | |
605 | } | |
2e1a3483 TG |
606 | break; |
607 | } | |
608 | } | |
609 | return ret; | |
610 | } | |
611 | ||
4cb28ced TG |
612 | /* |
613 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
614 | */ | |
615 | static void cpuhp_create(unsigned int cpu) | |
616 | { | |
617 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
618 | ||
5ebe7742 PZ |
619 | init_completion(&st->done_up); |
620 | init_completion(&st->done_down); | |
4cb28ced TG |
621 | } |
622 | ||
623 | static int cpuhp_should_run(unsigned int cpu) | |
624 | { | |
625 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
626 | ||
627 | return st->should_run; | |
628 | } | |
629 | ||
4cb28ced TG |
630 | /* |
631 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
632 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
633 | * |
634 | * Each invocation of this function by the smpboot thread does a single AP | |
635 | * state callback. | |
636 | * | |
637 | * It has 3 modes of operation: | |
638 | * - single: runs st->cb_state | |
639 | * - up: runs ++st->state, while st->state < st->target | |
640 | * - down: runs st->state--, while st->state > st->target | |
641 | * | |
642 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
643 | */ |
644 | static void cpuhp_thread_fun(unsigned int cpu) | |
645 | { | |
646 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
647 | bool bringup = st->bringup; |
648 | enum cpuhp_state state; | |
4cb28ced | 649 | |
f8b7530a NU |
650 | if (WARN_ON_ONCE(!st->should_run)) |
651 | return; | |
652 | ||
4cb28ced | 653 | /* |
4dddfb5f PZ |
654 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
655 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
656 | */ |
657 | smp_mb(); | |
4cb28ced | 658 | |
cb92173d PZ |
659 | /* |
660 | * The BP holds the hotplug lock, but we're now running on the AP, | |
661 | * ensure that anybody asserting the lock is held, will actually find | |
662 | * it so. | |
663 | */ | |
664 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 665 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 666 | |
a724632c | 667 | if (st->single) { |
4dddfb5f PZ |
668 | state = st->cb_state; |
669 | st->should_run = false; | |
670 | } else { | |
671 | if (bringup) { | |
672 | st->state++; | |
673 | state = st->state; | |
674 | st->should_run = (st->state < st->target); | |
675 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 676 | } else { |
4dddfb5f PZ |
677 | state = st->state; |
678 | st->state--; | |
679 | st->should_run = (st->state > st->target); | |
680 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 681 | } |
4dddfb5f PZ |
682 | } |
683 | ||
684 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
685 | ||
4dddfb5f PZ |
686 | if (cpuhp_is_atomic_state(state)) { |
687 | local_irq_disable(); | |
688 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
689 | local_irq_enable(); | |
3b9d6da6 | 690 | |
4dddfb5f PZ |
691 | /* |
692 | * STARTING/DYING must not fail! | |
693 | */ | |
694 | WARN_ON_ONCE(st->result); | |
4cb28ced | 695 | } else { |
4dddfb5f PZ |
696 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
697 | } | |
698 | ||
699 | if (st->result) { | |
700 | /* | |
701 | * If we fail on a rollback, we're up a creek without no | |
702 | * paddle, no way forward, no way back. We loose, thanks for | |
703 | * playing. | |
704 | */ | |
705 | WARN_ON_ONCE(st->rollback); | |
706 | st->should_run = false; | |
4cb28ced | 707 | } |
4dddfb5f | 708 | |
5f4b55e1 | 709 | cpuhp_lock_release(bringup); |
cb92173d | 710 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
711 | |
712 | if (!st->should_run) | |
5ebe7742 | 713 | complete_ap_thread(st, bringup); |
4cb28ced TG |
714 | } |
715 | ||
716 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 717 | static int |
cf392d10 TG |
718 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
719 | struct hlist_node *node) | |
4cb28ced TG |
720 | { |
721 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 722 | int ret; |
4cb28ced TG |
723 | |
724 | if (!cpu_online(cpu)) | |
725 | return 0; | |
726 | ||
5f4b55e1 PZ |
727 | cpuhp_lock_acquire(false); |
728 | cpuhp_lock_release(false); | |
729 | ||
730 | cpuhp_lock_acquire(true); | |
731 | cpuhp_lock_release(true); | |
49dfe2a6 | 732 | |
6a4e2451 TG |
733 | /* |
734 | * If we are up and running, use the hotplug thread. For early calls | |
735 | * we invoke the thread function directly. | |
736 | */ | |
737 | if (!st->thread) | |
96abb968 | 738 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 739 | |
4dddfb5f PZ |
740 | st->rollback = false; |
741 | st->last = NULL; | |
742 | ||
743 | st->node = node; | |
744 | st->bringup = bringup; | |
4cb28ced | 745 | st->cb_state = state; |
a724632c | 746 | st->single = true; |
a724632c | 747 | |
4dddfb5f | 748 | __cpuhp_kick_ap(st); |
4cb28ced | 749 | |
4cb28ced | 750 | /* |
4dddfb5f | 751 | * If we failed and did a partial, do a rollback. |
4cb28ced | 752 | */ |
4dddfb5f PZ |
753 | if ((ret = st->result) && st->last) { |
754 | st->rollback = true; | |
755 | st->bringup = !bringup; | |
756 | ||
757 | __cpuhp_kick_ap(st); | |
758 | } | |
759 | ||
1f7c70d6 TG |
760 | /* |
761 | * Clean up the leftovers so the next hotplug operation wont use stale | |
762 | * data. | |
763 | */ | |
764 | st->node = st->last = NULL; | |
4dddfb5f | 765 | return ret; |
1cf4f629 TG |
766 | } |
767 | ||
768 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
769 | { | |
770 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
771 | enum cpuhp_state prev_state = st->state; |
772 | int ret; | |
1cf4f629 | 773 | |
5f4b55e1 PZ |
774 | cpuhp_lock_acquire(false); |
775 | cpuhp_lock_release(false); | |
776 | ||
777 | cpuhp_lock_acquire(true); | |
778 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
779 | |
780 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
781 | ret = cpuhp_kick_ap(st, st->target); | |
782 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
783 | ||
784 | return ret; | |
4cb28ced TG |
785 | } |
786 | ||
787 | static struct smp_hotplug_thread cpuhp_threads = { | |
788 | .store = &cpuhp_state.thread, | |
789 | .create = &cpuhp_create, | |
790 | .thread_should_run = cpuhp_should_run, | |
791 | .thread_fn = cpuhp_thread_fun, | |
792 | .thread_comm = "cpuhp/%u", | |
793 | .selfparking = true, | |
794 | }; | |
795 | ||
796 | void __init cpuhp_threads_init(void) | |
797 | { | |
798 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
799 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
800 | } | |
801 | ||
777c6e0d | 802 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
803 | /** |
804 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
805 | * @cpu: a CPU id | |
806 | * | |
807 | * This function walks all processes, finds a valid mm struct for each one and | |
808 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
809 | * trivial, there are various non-obvious corner cases, which this function | |
810 | * tries to solve in a safe manner. | |
811 | * | |
812 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
813 | * be called only for an already offlined CPU. | |
814 | */ | |
cb79295e AV |
815 | void clear_tasks_mm_cpumask(int cpu) |
816 | { | |
817 | struct task_struct *p; | |
818 | ||
819 | /* | |
820 | * This function is called after the cpu is taken down and marked | |
821 | * offline, so its not like new tasks will ever get this cpu set in | |
822 | * their mm mask. -- Peter Zijlstra | |
823 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
824 | * full-fledged tasklist_lock. | |
825 | */ | |
e4cc2f87 | 826 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
827 | rcu_read_lock(); |
828 | for_each_process(p) { | |
829 | struct task_struct *t; | |
830 | ||
e4cc2f87 AV |
831 | /* |
832 | * Main thread might exit, but other threads may still have | |
833 | * a valid mm. Find one. | |
834 | */ | |
cb79295e AV |
835 | t = find_lock_task_mm(p); |
836 | if (!t) | |
837 | continue; | |
838 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
839 | task_unlock(t); | |
840 | } | |
841 | rcu_read_unlock(); | |
842 | } | |
843 | ||
1da177e4 | 844 | /* Take this CPU down. */ |
71cf5aee | 845 | static int take_cpu_down(void *_param) |
1da177e4 | 846 | { |
4baa0afc TG |
847 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
848 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 849 | int err, cpu = smp_processor_id(); |
724a8688 | 850 | int ret; |
1da177e4 | 851 | |
1da177e4 LT |
852 | /* Ensure this CPU doesn't handle any more interrupts. */ |
853 | err = __cpu_disable(); | |
854 | if (err < 0) | |
f3705136 | 855 | return err; |
1da177e4 | 856 | |
a724632c TG |
857 | /* |
858 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
859 | * do this step again. | |
860 | */ | |
861 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
862 | st->state--; | |
4baa0afc | 863 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
864 | for (; st->state > target; st->state--) { |
865 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
866 | /* | |
867 | * DYING must not fail! | |
868 | */ | |
869 | WARN_ON_ONCE(ret); | |
870 | } | |
4baa0afc | 871 | |
52c063d1 TG |
872 | /* Give up timekeeping duties */ |
873 | tick_handover_do_timer(); | |
1b72d432 TG |
874 | /* Remove CPU from timer broadcasting */ |
875 | tick_offline_cpu(cpu); | |
14e568e7 | 876 | /* Park the stopper thread */ |
090e77c3 | 877 | stop_machine_park(cpu); |
f3705136 | 878 | return 0; |
1da177e4 LT |
879 | } |
880 | ||
98458172 | 881 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 882 | { |
e69aab13 | 883 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 884 | int err; |
1da177e4 | 885 | |
2a58c527 | 886 | /* Park the smpboot threads */ |
1cf4f629 TG |
887 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
888 | ||
6acce3ef | 889 | /* |
a8994181 TG |
890 | * Prevent irq alloc/free while the dying cpu reorganizes the |
891 | * interrupt affinities. | |
6acce3ef | 892 | */ |
a8994181 | 893 | irq_lock_sparse(); |
6acce3ef | 894 | |
a8994181 TG |
895 | /* |
896 | * So now all preempt/rcu users must observe !cpu_active(). | |
897 | */ | |
210e2133 | 898 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 899 | if (err) { |
3b9d6da6 | 900 | /* CPU refused to die */ |
a8994181 | 901 | irq_unlock_sparse(); |
3b9d6da6 SAS |
902 | /* Unpark the hotplug thread so we can rollback there */ |
903 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 904 | return err; |
8fa1d7d3 | 905 | } |
04321587 | 906 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 907 | |
48c5ccae | 908 | /* |
5b1ead68 BJ |
909 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
910 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 911 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
912 | * |
913 | * Wait for the stop thread to go away. | |
48c5ccae | 914 | */ |
5ebe7742 | 915 | wait_for_ap_thread(st, false); |
e69aab13 | 916 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 917 | |
a8994181 TG |
918 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
919 | irq_unlock_sparse(); | |
920 | ||
345527b1 | 921 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
922 | /* This actually kills the CPU. */ |
923 | __cpu_die(cpu); | |
924 | ||
a49b116d | 925 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 926 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
927 | return 0; |
928 | } | |
1da177e4 | 929 | |
71f87b2f TG |
930 | static void cpuhp_complete_idle_dead(void *arg) |
931 | { | |
932 | struct cpuhp_cpu_state *st = arg; | |
933 | ||
5ebe7742 | 934 | complete_ap_thread(st, false); |
71f87b2f TG |
935 | } |
936 | ||
e69aab13 TG |
937 | void cpuhp_report_idle_dead(void) |
938 | { | |
939 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
940 | ||
941 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 942 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
943 | st->state = CPUHP_AP_IDLE_DEAD; |
944 | /* | |
945 | * We cannot call complete after rcu_report_dead() so we delegate it | |
946 | * to an online cpu. | |
947 | */ | |
948 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
949 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
950 | } |
951 | ||
4dddfb5f PZ |
952 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
953 | { | |
6fb86d97 MO |
954 | for (st->state++; st->state < st->target; st->state++) |
955 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
4dddfb5f PZ |
956 | } |
957 | ||
958 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
959 | enum cpuhp_state target) | |
960 | { | |
961 | enum cpuhp_state prev_state = st->state; | |
962 | int ret = 0; | |
963 | ||
964 | for (; st->state > target; st->state--) { | |
965 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
966 | if (ret) { | |
967 | st->target = prev_state; | |
69fa6eb7 TG |
968 | if (st->state < prev_state) |
969 | undo_cpu_down(cpu, st); | |
4dddfb5f PZ |
970 | break; |
971 | } | |
972 | } | |
973 | return ret; | |
974 | } | |
cff7d378 | 975 | |
98458172 | 976 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
977 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
978 | enum cpuhp_state target) | |
98458172 | 979 | { |
cff7d378 TG |
980 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
981 | int prev_state, ret = 0; | |
98458172 TG |
982 | |
983 | if (num_online_cpus() == 1) | |
984 | return -EBUSY; | |
985 | ||
757c989b | 986 | if (!cpu_present(cpu)) |
98458172 TG |
987 | return -EINVAL; |
988 | ||
8f553c49 | 989 | cpus_write_lock(); |
98458172 TG |
990 | |
991 | cpuhp_tasks_frozen = tasks_frozen; | |
992 | ||
4dddfb5f | 993 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
994 | /* |
995 | * If the current CPU state is in the range of the AP hotplug thread, | |
996 | * then we need to kick the thread. | |
997 | */ | |
8df3e07e | 998 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 999 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
1000 | ret = cpuhp_kick_ap_work(cpu); |
1001 | /* | |
1002 | * The AP side has done the error rollback already. Just | |
1003 | * return the error code.. | |
1004 | */ | |
1005 | if (ret) | |
1006 | goto out; | |
1007 | ||
1008 | /* | |
1009 | * We might have stopped still in the range of the AP hotplug | |
1010 | * thread. Nothing to do anymore. | |
1011 | */ | |
8df3e07e | 1012 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1013 | goto out; |
4dddfb5f PZ |
1014 | |
1015 | st->target = target; | |
1cf4f629 TG |
1016 | } |
1017 | /* | |
8df3e07e | 1018 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1019 | * to do the further cleanups. |
1020 | */ | |
a724632c | 1021 | ret = cpuhp_down_callbacks(cpu, st, target); |
69fa6eb7 | 1022 | if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
1023 | cpuhp_reset_state(st, prev_state); |
1024 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 1025 | } |
98458172 | 1026 | |
1cf4f629 | 1027 | out: |
8f553c49 | 1028 | cpus_write_unlock(); |
941154bd TG |
1029 | /* |
1030 | * Do post unplug cleanup. This is still protected against | |
1031 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1032 | */ | |
1033 | lockup_detector_cleanup(); | |
a74cfffb | 1034 | arch_smt_update(); |
cff7d378 | 1035 | return ret; |
e3920fb4 RW |
1036 | } |
1037 | ||
cc1fe215 TG |
1038 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1039 | { | |
1040 | if (cpu_hotplug_disabled) | |
1041 | return -EBUSY; | |
1042 | return _cpu_down(cpu, 0, target); | |
1043 | } | |
1044 | ||
af1f4045 | 1045 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1046 | { |
9ea09af3 | 1047 | int err; |
e3920fb4 | 1048 | |
d221938c | 1049 | cpu_maps_update_begin(); |
cc1fe215 | 1050 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1051 | cpu_maps_update_done(); |
1da177e4 LT |
1052 | return err; |
1053 | } | |
4dddfb5f | 1054 | |
af1f4045 TG |
1055 | int cpu_down(unsigned int cpu) |
1056 | { | |
1057 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1058 | } | |
b62b8ef9 | 1059 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f PZ |
1060 | |
1061 | #else | |
1062 | #define takedown_cpu NULL | |
1da177e4 LT |
1063 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1064 | ||
4baa0afc | 1065 | /** |
ee1e714b | 1066 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1067 | * @cpu: cpu that just started |
1068 | * | |
4baa0afc TG |
1069 | * It must be called by the arch code on the new cpu, before the new cpu |
1070 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1071 | */ | |
1072 | void notify_cpu_starting(unsigned int cpu) | |
1073 | { | |
1074 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1075 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1076 | int ret; |
4baa0afc | 1077 | |
0c6d4576 | 1078 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1079 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
4baa0afc | 1080 | while (st->state < target) { |
4baa0afc | 1081 | st->state++; |
724a8688 PZ |
1082 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1083 | /* | |
1084 | * STARTING must not fail! | |
1085 | */ | |
1086 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1087 | } |
1088 | } | |
1089 | ||
949338e3 | 1090 | /* |
9cd4f1a4 TG |
1091 | * Called from the idle task. Wake up the controlling task which brings the |
1092 | * stopper and the hotplug thread of the upcoming CPU up and then delegates | |
1093 | * the rest of the online bringup to the hotplug thread. | |
949338e3 | 1094 | */ |
8df3e07e | 1095 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1096 | { |
8df3e07e | 1097 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1098 | |
1099 | /* Happens for the boot cpu */ | |
1100 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1101 | return; | |
1102 | ||
1103 | st->state = CPUHP_AP_ONLINE_IDLE; | |
5ebe7742 | 1104 | complete_ap_thread(st, true); |
949338e3 TG |
1105 | } |
1106 | ||
e3920fb4 | 1107 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1108 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1109 | { |
cff7d378 | 1110 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1111 | struct task_struct *idle; |
2e1a3483 | 1112 | int ret = 0; |
1da177e4 | 1113 | |
8f553c49 | 1114 | cpus_write_lock(); |
38498a67 | 1115 | |
757c989b | 1116 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1117 | ret = -EINVAL; |
1118 | goto out; | |
1119 | } | |
1120 | ||
757c989b TG |
1121 | /* |
1122 | * The caller of do_cpu_up might have raced with another | |
1123 | * caller. Ignore it for now. | |
1124 | */ | |
1125 | if (st->state >= target) | |
38498a67 | 1126 | goto out; |
757c989b TG |
1127 | |
1128 | if (st->state == CPUHP_OFFLINE) { | |
1129 | /* Let it fail before we try to bring the cpu up */ | |
1130 | idle = idle_thread_get(cpu); | |
1131 | if (IS_ERR(idle)) { | |
1132 | ret = PTR_ERR(idle); | |
1133 | goto out; | |
1134 | } | |
3bb5d2ee | 1135 | } |
38498a67 | 1136 | |
ba997462 TG |
1137 | cpuhp_tasks_frozen = tasks_frozen; |
1138 | ||
4dddfb5f | 1139 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1140 | /* |
1141 | * If the current CPU state is in the range of the AP hotplug thread, | |
1142 | * then we need to kick the thread once more. | |
1143 | */ | |
8df3e07e | 1144 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1145 | ret = cpuhp_kick_ap_work(cpu); |
1146 | /* | |
1147 | * The AP side has done the error rollback already. Just | |
1148 | * return the error code.. | |
1149 | */ | |
1150 | if (ret) | |
1151 | goto out; | |
1152 | } | |
1153 | ||
1154 | /* | |
1155 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1156 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1157 | * responsible for bringing it up to the target state. |
1158 | */ | |
8df3e07e | 1159 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1160 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1161 | out: |
8f553c49 | 1162 | cpus_write_unlock(); |
a74cfffb | 1163 | arch_smt_update(); |
e3920fb4 RW |
1164 | return ret; |
1165 | } | |
1166 | ||
af1f4045 | 1167 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1168 | { |
1169 | int err = 0; | |
cf23422b | 1170 | |
e0b582ec | 1171 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1172 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1173 | cpu); | |
87d5e023 | 1174 | #if defined(CONFIG_IA64) |
84117da5 | 1175 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1176 | #endif |
1177 | return -EINVAL; | |
1178 | } | |
e3920fb4 | 1179 | |
01b0f197 TK |
1180 | err = try_online_node(cpu_to_node(cpu)); |
1181 | if (err) | |
1182 | return err; | |
cf23422b | 1183 | |
d221938c | 1184 | cpu_maps_update_begin(); |
e761b772 MK |
1185 | |
1186 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1187 | err = -EBUSY; |
e761b772 MK |
1188 | goto out; |
1189 | } | |
05736e4a TG |
1190 | if (!cpu_smt_allowed(cpu)) { |
1191 | err = -EPERM; | |
1192 | goto out; | |
1193 | } | |
e761b772 | 1194 | |
af1f4045 | 1195 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1196 | out: |
d221938c | 1197 | cpu_maps_update_done(); |
e3920fb4 RW |
1198 | return err; |
1199 | } | |
af1f4045 TG |
1200 | |
1201 | int cpu_up(unsigned int cpu) | |
1202 | { | |
1203 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1204 | } | |
a513f6ba | 1205 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1206 | |
f3de4be9 | 1207 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1208 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1209 | |
d391e552 | 1210 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1211 | { |
d391e552 | 1212 | int cpu, error = 0; |
e3920fb4 | 1213 | |
d221938c | 1214 | cpu_maps_update_begin(); |
9ca12ac0 | 1215 | if (primary == -1) { |
d391e552 | 1216 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1217 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1218 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1219 | } else { | |
1220 | if (!cpu_online(primary)) | |
1221 | primary = cpumask_first(cpu_online_mask); | |
1222 | } | |
1223 | ||
9ee349ad XF |
1224 | /* |
1225 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1226 | * with the userspace trying to use the CPU hotplug at the same time |
1227 | */ | |
e0b582ec | 1228 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1229 | |
84117da5 | 1230 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1231 | for_each_online_cpu(cpu) { |
d391e552 | 1232 | if (cpu == primary) |
e3920fb4 | 1233 | continue; |
a66d955e PK |
1234 | |
1235 | if (pm_wakeup_pending()) { | |
1236 | pr_info("Wakeup pending. Abort CPU freeze\n"); | |
1237 | error = -EBUSY; | |
1238 | break; | |
1239 | } | |
1240 | ||
bb3632c6 | 1241 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1242 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1243 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1244 | if (!error) |
e0b582ec | 1245 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1246 | else { |
84117da5 | 1247 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1248 | break; |
1249 | } | |
1250 | } | |
86886e55 | 1251 | |
89af7ba5 | 1252 | if (!error) |
e3920fb4 | 1253 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1254 | else |
84117da5 | 1255 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1256 | |
1257 | /* | |
1258 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1259 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1260 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1261 | */ | |
1262 | cpu_hotplug_disabled++; | |
1263 | ||
d221938c | 1264 | cpu_maps_update_done(); |
e3920fb4 RW |
1265 | return error; |
1266 | } | |
1267 | ||
d0af9eed SS |
1268 | void __weak arch_enable_nonboot_cpus_begin(void) |
1269 | { | |
1270 | } | |
1271 | ||
1272 | void __weak arch_enable_nonboot_cpus_end(void) | |
1273 | { | |
1274 | } | |
1275 | ||
71cf5aee | 1276 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1277 | { |
1278 | int cpu, error; | |
1279 | ||
1280 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1281 | cpu_maps_update_begin(); |
01b41159 | 1282 | __cpu_hotplug_enable(); |
e0b582ec | 1283 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1284 | goto out; |
e3920fb4 | 1285 | |
84117da5 | 1286 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1287 | |
1288 | arch_enable_nonboot_cpus_begin(); | |
1289 | ||
e0b582ec | 1290 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1291 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1292 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1293 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1294 | if (!error) { |
84117da5 | 1295 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1296 | continue; |
1297 | } | |
84117da5 | 1298 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1299 | } |
d0af9eed SS |
1300 | |
1301 | arch_enable_nonboot_cpus_end(); | |
1302 | ||
e0b582ec | 1303 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1304 | out: |
d221938c | 1305 | cpu_maps_update_done(); |
1da177e4 | 1306 | } |
e0b582ec | 1307 | |
d7268a31 | 1308 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1309 | { |
1310 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1311 | return -ENOMEM; | |
1312 | return 0; | |
1313 | } | |
1314 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1315 | |
79cfbdfa SB |
1316 | /* |
1317 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1318 | * ensure that the state of the system with respect to the tasks being frozen | |
1319 | * or not, as reported by the notification, remains unchanged *throughout the | |
1320 | * duration* of the execution of the callbacks. | |
1321 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1322 | * | |
1323 | * This synchronization is implemented by mutually excluding regular CPU | |
1324 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1325 | * Hibernate notifications. | |
1326 | */ | |
1327 | static int | |
1328 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1329 | unsigned long action, void *ptr) | |
1330 | { | |
1331 | switch (action) { | |
1332 | ||
1333 | case PM_SUSPEND_PREPARE: | |
1334 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1335 | cpu_hotplug_disable(); |
79cfbdfa SB |
1336 | break; |
1337 | ||
1338 | case PM_POST_SUSPEND: | |
1339 | case PM_POST_HIBERNATION: | |
16e53dbf | 1340 | cpu_hotplug_enable(); |
79cfbdfa SB |
1341 | break; |
1342 | ||
1343 | default: | |
1344 | return NOTIFY_DONE; | |
1345 | } | |
1346 | ||
1347 | return NOTIFY_OK; | |
1348 | } | |
1349 | ||
1350 | ||
d7268a31 | 1351 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1352 | { |
6e32d479 FY |
1353 | /* |
1354 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1355 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1356 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1357 | */ | |
79cfbdfa SB |
1358 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1359 | return 0; | |
1360 | } | |
1361 | core_initcall(cpu_hotplug_pm_sync_init); | |
1362 | ||
f3de4be9 | 1363 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1364 | |
8ce371f9 PZ |
1365 | int __boot_cpu_id; |
1366 | ||
68f4f1ec | 1367 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1368 | |
cff7d378 | 1369 | /* Boot processor state steps */ |
17a2f1ce | 1370 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1371 | [CPUHP_OFFLINE] = { |
1372 | .name = "offline", | |
3c1627e9 TG |
1373 | .startup.single = NULL, |
1374 | .teardown.single = NULL, | |
cff7d378 TG |
1375 | }, |
1376 | #ifdef CONFIG_SMP | |
1377 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1378 | .name = "threads:prepare", |
3c1627e9 TG |
1379 | .startup.single = smpboot_create_threads, |
1380 | .teardown.single = NULL, | |
757c989b | 1381 | .cant_stop = true, |
cff7d378 | 1382 | }, |
00e16c3d | 1383 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1384 | .name = "perf:prepare", |
1385 | .startup.single = perf_event_init_cpu, | |
1386 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1387 | }, |
7ee681b2 | 1388 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1389 | .name = "workqueue:prepare", |
1390 | .startup.single = workqueue_prepare_cpu, | |
1391 | .teardown.single = NULL, | |
7ee681b2 | 1392 | }, |
27590dc1 | 1393 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1394 | .name = "hrtimers:prepare", |
1395 | .startup.single = hrtimers_prepare_cpu, | |
1396 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1397 | }, |
31487f83 | 1398 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1399 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1400 | .startup.single = smpcfd_prepare_cpu, |
1401 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1402 | }, |
e6d4989a RW |
1403 | [CPUHP_RELAY_PREPARE] = { |
1404 | .name = "relay:prepare", | |
1405 | .startup.single = relay_prepare_cpu, | |
1406 | .teardown.single = NULL, | |
1407 | }, | |
6731d4f1 SAS |
1408 | [CPUHP_SLAB_PREPARE] = { |
1409 | .name = "slab:prepare", | |
1410 | .startup.single = slab_prepare_cpu, | |
1411 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1412 | }, |
4df83742 | 1413 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1414 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1415 | .startup.single = rcutree_prepare_cpu, |
1416 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1417 | }, |
4fae16df RC |
1418 | /* |
1419 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1420 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1421 | * otherwise a RCU stall occurs. | |
1422 | */ | |
26456f87 | 1423 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1424 | .name = "timers:prepare", |
26456f87 | 1425 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1426 | .teardown.single = timers_dead_cpu, |
4fae16df | 1427 | }, |
d10ef6f9 | 1428 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1429 | [CPUHP_BRINGUP_CPU] = { |
1430 | .name = "cpu:bringup", | |
3c1627e9 TG |
1431 | .startup.single = bringup_cpu, |
1432 | .teardown.single = NULL, | |
757c989b | 1433 | .cant_stop = true, |
4baa0afc | 1434 | }, |
d10ef6f9 TG |
1435 | /* Final state before CPU kills itself */ |
1436 | [CPUHP_AP_IDLE_DEAD] = { | |
1437 | .name = "idle:dead", | |
1438 | }, | |
1439 | /* | |
1440 | * Last state before CPU enters the idle loop to die. Transient state | |
1441 | * for synchronization. | |
1442 | */ | |
1443 | [CPUHP_AP_OFFLINE] = { | |
1444 | .name = "ap:offline", | |
1445 | .cant_stop = true, | |
1446 | }, | |
9cf7243d TG |
1447 | /* First state is scheduler control. Interrupts are disabled */ |
1448 | [CPUHP_AP_SCHED_STARTING] = { | |
1449 | .name = "sched:starting", | |
3c1627e9 TG |
1450 | .startup.single = sched_cpu_starting, |
1451 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1452 | }, |
4df83742 | 1453 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1454 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1455 | .startup.single = NULL, |
1456 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1457 | }, |
46febd37 LJ |
1458 | [CPUHP_AP_SMPCFD_DYING] = { |
1459 | .name = "smpcfd:dying", | |
1460 | .startup.single = NULL, | |
1461 | .teardown.single = smpcfd_dying_cpu, | |
1462 | }, | |
d10ef6f9 TG |
1463 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1464 | * state for synchronsization */ | |
1465 | [CPUHP_AP_ONLINE] = { | |
1466 | .name = "ap:online", | |
1467 | }, | |
17a2f1ce LJ |
1468 | /* |
1469 | * Handled on controll processor until the plugged processor manages | |
1470 | * this itself. | |
1471 | */ | |
1472 | [CPUHP_TEARDOWN_CPU] = { | |
1473 | .name = "cpu:teardown", | |
1474 | .startup.single = NULL, | |
1475 | .teardown.single = takedown_cpu, | |
1476 | .cant_stop = true, | |
1477 | }, | |
d10ef6f9 | 1478 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1479 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1480 | .name = "smpboot/threads:online", |
3c1627e9 | 1481 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1482 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1483 | }, |
c5cb83bb TG |
1484 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1485 | .name = "irq/affinity:online", | |
1486 | .startup.single = irq_affinity_online_cpu, | |
1487 | .teardown.single = NULL, | |
1488 | }, | |
00e16c3d | 1489 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1490 | .name = "perf:online", |
1491 | .startup.single = perf_event_init_cpu, | |
1492 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1493 | }, |
9cf57731 PZ |
1494 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1495 | .name = "lockup_detector:online", | |
1496 | .startup.single = lockup_detector_online_cpu, | |
1497 | .teardown.single = lockup_detector_offline_cpu, | |
1498 | }, | |
7ee681b2 | 1499 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1500 | .name = "workqueue:online", |
1501 | .startup.single = workqueue_online_cpu, | |
1502 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1503 | }, |
4df83742 | 1504 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1505 | .name = "RCU/tree:online", |
3c1627e9 TG |
1506 | .startup.single = rcutree_online_cpu, |
1507 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1508 | }, |
4baa0afc | 1509 | #endif |
d10ef6f9 TG |
1510 | /* |
1511 | * The dynamically registered state space is here | |
1512 | */ | |
1513 | ||
aaddd7d1 TG |
1514 | #ifdef CONFIG_SMP |
1515 | /* Last state is scheduler control setting the cpu active */ | |
1516 | [CPUHP_AP_ACTIVE] = { | |
1517 | .name = "sched:active", | |
3c1627e9 TG |
1518 | .startup.single = sched_cpu_activate, |
1519 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1520 | }, |
1521 | #endif | |
1522 | ||
d10ef6f9 | 1523 | /* CPU is fully up and running. */ |
4baa0afc TG |
1524 | [CPUHP_ONLINE] = { |
1525 | .name = "online", | |
3c1627e9 TG |
1526 | .startup.single = NULL, |
1527 | .teardown.single = NULL, | |
4baa0afc TG |
1528 | }, |
1529 | }; | |
1530 | ||
5b7aa87e TG |
1531 | /* Sanity check for callbacks */ |
1532 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1533 | { | |
1534 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1535 | return -EINVAL; | |
1536 | return 0; | |
1537 | } | |
1538 | ||
dc280d93 TG |
1539 | /* |
1540 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1541 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1542 | * by having no name assigned. | |
1543 | */ | |
1544 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1545 | { | |
4205e478 TG |
1546 | enum cpuhp_state i, end; |
1547 | struct cpuhp_step *step; | |
dc280d93 | 1548 | |
4205e478 TG |
1549 | switch (state) { |
1550 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1551 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1552 | end = CPUHP_AP_ONLINE_DYN_END; |
1553 | break; | |
1554 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1555 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1556 | end = CPUHP_BP_PREPARE_DYN_END; |
1557 | break; | |
1558 | default: | |
1559 | return -EINVAL; | |
1560 | } | |
1561 | ||
1562 | for (i = state; i <= end; i++, step++) { | |
1563 | if (!step->name) | |
dc280d93 TG |
1564 | return i; |
1565 | } | |
1566 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1567 | return -ENOSPC; | |
1568 | } | |
1569 | ||
1570 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1571 | int (*startup)(unsigned int cpu), | |
1572 | int (*teardown)(unsigned int cpu), | |
1573 | bool multi_instance) | |
5b7aa87e TG |
1574 | { |
1575 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1576 | struct cpuhp_step *sp; | |
dc280d93 | 1577 | int ret = 0; |
5b7aa87e | 1578 | |
0c96b273 EB |
1579 | /* |
1580 | * If name is NULL, then the state gets removed. | |
1581 | * | |
1582 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1583 | * the first allocation from these dynamic ranges, so the removal | |
1584 | * would trigger a new allocation and clear the wrong (already | |
1585 | * empty) state, leaving the callbacks of the to be cleared state | |
1586 | * dangling, which causes wreckage on the next hotplug operation. | |
1587 | */ | |
1588 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1589 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1590 | ret = cpuhp_reserve_state(state); |
1591 | if (ret < 0) | |
dc434e05 | 1592 | return ret; |
dc280d93 TG |
1593 | state = ret; |
1594 | } | |
5b7aa87e | 1595 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1596 | if (name && sp->name) |
1597 | return -EBUSY; | |
1598 | ||
3c1627e9 TG |
1599 | sp->startup.single = startup; |
1600 | sp->teardown.single = teardown; | |
5b7aa87e | 1601 | sp->name = name; |
cf392d10 TG |
1602 | sp->multi_instance = multi_instance; |
1603 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1604 | return ret; |
5b7aa87e TG |
1605 | } |
1606 | ||
1607 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1608 | { | |
3c1627e9 | 1609 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1610 | } |
1611 | ||
5b7aa87e TG |
1612 | /* |
1613 | * Call the startup/teardown function for a step either on the AP or | |
1614 | * on the current CPU. | |
1615 | */ | |
cf392d10 TG |
1616 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1617 | struct hlist_node *node) | |
5b7aa87e | 1618 | { |
a724632c | 1619 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1620 | int ret; |
1621 | ||
4dddfb5f PZ |
1622 | /* |
1623 | * If there's nothing to do, we done. | |
1624 | * Relies on the union for multi_instance. | |
1625 | */ | |
3c1627e9 TG |
1626 | if ((bringup && !sp->startup.single) || |
1627 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1628 | return 0; |
5b7aa87e TG |
1629 | /* |
1630 | * The non AP bound callbacks can fail on bringup. On teardown | |
1631 | * e.g. module removal we crash for now. | |
1632 | */ | |
1cf4f629 TG |
1633 | #ifdef CONFIG_SMP |
1634 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1635 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1636 | else |
96abb968 | 1637 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1638 | #else |
96abb968 | 1639 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1640 | #endif |
5b7aa87e TG |
1641 | BUG_ON(ret && !bringup); |
1642 | return ret; | |
1643 | } | |
1644 | ||
1645 | /* | |
1646 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1647 | * | |
1648 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1649 | */ | |
1650 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1651 | struct hlist_node *node) |
5b7aa87e TG |
1652 | { |
1653 | int cpu; | |
1654 | ||
5b7aa87e TG |
1655 | /* Roll back the already executed steps on the other cpus */ |
1656 | for_each_present_cpu(cpu) { | |
1657 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1658 | int cpustate = st->state; | |
1659 | ||
1660 | if (cpu >= failedcpu) | |
1661 | break; | |
1662 | ||
1663 | /* Did we invoke the startup call on that cpu ? */ | |
1664 | if (cpustate >= state) | |
cf392d10 | 1665 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1666 | } |
1667 | } | |
1668 | ||
9805c673 TG |
1669 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1670 | struct hlist_node *node, | |
1671 | bool invoke) | |
cf392d10 TG |
1672 | { |
1673 | struct cpuhp_step *sp; | |
1674 | int cpu; | |
1675 | int ret; | |
1676 | ||
9805c673 TG |
1677 | lockdep_assert_cpus_held(); |
1678 | ||
cf392d10 TG |
1679 | sp = cpuhp_get_step(state); |
1680 | if (sp->multi_instance == false) | |
1681 | return -EINVAL; | |
1682 | ||
dc434e05 | 1683 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1684 | |
3c1627e9 | 1685 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1686 | goto add_node; |
1687 | ||
1688 | /* | |
1689 | * Try to call the startup callback for each present cpu | |
1690 | * depending on the hotplug state of the cpu. | |
1691 | */ | |
1692 | for_each_present_cpu(cpu) { | |
1693 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1694 | int cpustate = st->state; | |
1695 | ||
1696 | if (cpustate < state) | |
1697 | continue; | |
1698 | ||
1699 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1700 | if (ret) { | |
3c1627e9 | 1701 | if (sp->teardown.multi) |
cf392d10 | 1702 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1703 | goto unlock; |
cf392d10 TG |
1704 | } |
1705 | } | |
1706 | add_node: | |
1707 | ret = 0; | |
cf392d10 | 1708 | hlist_add_head(node, &sp->list); |
dc434e05 | 1709 | unlock: |
cf392d10 | 1710 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1711 | return ret; |
1712 | } | |
1713 | ||
1714 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1715 | bool invoke) | |
1716 | { | |
1717 | int ret; | |
1718 | ||
1719 | cpus_read_lock(); | |
1720 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1721 | cpus_read_unlock(); |
cf392d10 TG |
1722 | return ret; |
1723 | } | |
1724 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1725 | ||
5b7aa87e | 1726 | /** |
71def423 | 1727 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1728 | * @state: The state to setup |
1729 | * @invoke: If true, the startup function is invoked for cpus where | |
1730 | * cpu state >= @state | |
1731 | * @startup: startup callback function | |
1732 | * @teardown: teardown callback function | |
1733 | * @multi_instance: State is set up for multiple instances which get | |
1734 | * added afterwards. | |
5b7aa87e | 1735 | * |
71def423 | 1736 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1737 | * Returns: |
1738 | * On success: | |
1739 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1740 | * 0 for all other states | |
1741 | * On failure: proper (negative) error code | |
5b7aa87e | 1742 | */ |
71def423 SAS |
1743 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1744 | const char *name, bool invoke, | |
1745 | int (*startup)(unsigned int cpu), | |
1746 | int (*teardown)(unsigned int cpu), | |
1747 | bool multi_instance) | |
5b7aa87e TG |
1748 | { |
1749 | int cpu, ret = 0; | |
b9d9d691 | 1750 | bool dynstate; |
5b7aa87e | 1751 | |
71def423 SAS |
1752 | lockdep_assert_cpus_held(); |
1753 | ||
5b7aa87e TG |
1754 | if (cpuhp_cb_check(state) || !name) |
1755 | return -EINVAL; | |
1756 | ||
dc434e05 | 1757 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1758 | |
dc280d93 TG |
1759 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1760 | multi_instance); | |
5b7aa87e | 1761 | |
b9d9d691 TG |
1762 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1763 | if (ret > 0 && dynstate) { | |
1764 | state = ret; | |
1765 | ret = 0; | |
1766 | } | |
1767 | ||
dc280d93 | 1768 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1769 | goto out; |
1770 | ||
1771 | /* | |
1772 | * Try to call the startup callback for each present cpu | |
1773 | * depending on the hotplug state of the cpu. | |
1774 | */ | |
1775 | for_each_present_cpu(cpu) { | |
1776 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1777 | int cpustate = st->state; | |
1778 | ||
1779 | if (cpustate < state) | |
1780 | continue; | |
1781 | ||
cf392d10 | 1782 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1783 | if (ret) { |
a724632c | 1784 | if (teardown) |
cf392d10 TG |
1785 | cpuhp_rollback_install(cpu, state, NULL); |
1786 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1787 | goto out; |
1788 | } | |
1789 | } | |
1790 | out: | |
dc434e05 | 1791 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1792 | /* |
1793 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1794 | * dynamically allocated state in case of success. | |
1795 | */ | |
b9d9d691 | 1796 | if (!ret && dynstate) |
5b7aa87e TG |
1797 | return state; |
1798 | return ret; | |
1799 | } | |
71def423 SAS |
1800 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1801 | ||
1802 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1803 | const char *name, bool invoke, | |
1804 | int (*startup)(unsigned int cpu), | |
1805 | int (*teardown)(unsigned int cpu), | |
1806 | bool multi_instance) | |
1807 | { | |
1808 | int ret; | |
1809 | ||
1810 | cpus_read_lock(); | |
1811 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1812 | teardown, multi_instance); | |
1813 | cpus_read_unlock(); | |
1814 | return ret; | |
1815 | } | |
5b7aa87e TG |
1816 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1817 | ||
cf392d10 TG |
1818 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1819 | struct hlist_node *node, bool invoke) | |
1820 | { | |
1821 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1822 | int cpu; | |
1823 | ||
1824 | BUG_ON(cpuhp_cb_check(state)); | |
1825 | ||
1826 | if (!sp->multi_instance) | |
1827 | return -EINVAL; | |
1828 | ||
8f553c49 | 1829 | cpus_read_lock(); |
dc434e05 SAS |
1830 | mutex_lock(&cpuhp_state_mutex); |
1831 | ||
cf392d10 TG |
1832 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1833 | goto remove; | |
1834 | /* | |
1835 | * Call the teardown callback for each present cpu depending | |
1836 | * on the hotplug state of the cpu. This function is not | |
1837 | * allowed to fail currently! | |
1838 | */ | |
1839 | for_each_present_cpu(cpu) { | |
1840 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1841 | int cpustate = st->state; | |
1842 | ||
1843 | if (cpustate >= state) | |
1844 | cpuhp_issue_call(cpu, state, false, node); | |
1845 | } | |
1846 | ||
1847 | remove: | |
cf392d10 TG |
1848 | hlist_del(node); |
1849 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1850 | cpus_read_unlock(); |
cf392d10 TG |
1851 | |
1852 | return 0; | |
1853 | } | |
1854 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1855 | |
5b7aa87e | 1856 | /** |
71def423 | 1857 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1858 | * @state: The state to remove |
1859 | * @invoke: If true, the teardown function is invoked for cpus where | |
1860 | * cpu state >= @state | |
1861 | * | |
71def423 | 1862 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1863 | * The teardown callback is currently not allowed to fail. Think |
1864 | * about module removal! | |
1865 | */ | |
71def423 | 1866 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1867 | { |
cf392d10 | 1868 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1869 | int cpu; |
1870 | ||
1871 | BUG_ON(cpuhp_cb_check(state)); | |
1872 | ||
71def423 | 1873 | lockdep_assert_cpus_held(); |
5b7aa87e | 1874 | |
dc434e05 | 1875 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1876 | if (sp->multi_instance) { |
1877 | WARN(!hlist_empty(&sp->list), | |
1878 | "Error: Removing state %d which has instances left.\n", | |
1879 | state); | |
1880 | goto remove; | |
1881 | } | |
1882 | ||
a724632c | 1883 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1884 | goto remove; |
1885 | ||
1886 | /* | |
1887 | * Call the teardown callback for each present cpu depending | |
1888 | * on the hotplug state of the cpu. This function is not | |
1889 | * allowed to fail currently! | |
1890 | */ | |
1891 | for_each_present_cpu(cpu) { | |
1892 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1893 | int cpustate = st->state; | |
1894 | ||
1895 | if (cpustate >= state) | |
cf392d10 | 1896 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1897 | } |
1898 | remove: | |
cf392d10 | 1899 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1900 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1901 | } |
1902 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1903 | ||
1904 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1905 | { | |
1906 | cpus_read_lock(); | |
1907 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 1908 | cpus_read_unlock(); |
5b7aa87e TG |
1909 | } |
1910 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1911 | ||
98f8cdce TG |
1912 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1913 | static ssize_t show_cpuhp_state(struct device *dev, | |
1914 | struct device_attribute *attr, char *buf) | |
1915 | { | |
1916 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1917 | ||
1918 | return sprintf(buf, "%d\n", st->state); | |
1919 | } | |
1920 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1921 | ||
757c989b TG |
1922 | static ssize_t write_cpuhp_target(struct device *dev, |
1923 | struct device_attribute *attr, | |
1924 | const char *buf, size_t count) | |
1925 | { | |
1926 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1927 | struct cpuhp_step *sp; | |
1928 | int target, ret; | |
1929 | ||
1930 | ret = kstrtoint(buf, 10, &target); | |
1931 | if (ret) | |
1932 | return ret; | |
1933 | ||
1934 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1935 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1936 | return -EINVAL; | |
1937 | #else | |
1938 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1939 | return -EINVAL; | |
1940 | #endif | |
1941 | ||
1942 | ret = lock_device_hotplug_sysfs(); | |
1943 | if (ret) | |
1944 | return ret; | |
1945 | ||
1946 | mutex_lock(&cpuhp_state_mutex); | |
1947 | sp = cpuhp_get_step(target); | |
1948 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1949 | mutex_unlock(&cpuhp_state_mutex); | |
1950 | if (ret) | |
40da1b11 | 1951 | goto out; |
757c989b TG |
1952 | |
1953 | if (st->state < target) | |
1954 | ret = do_cpu_up(dev->id, target); | |
1955 | else | |
1956 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 1957 | out: |
757c989b TG |
1958 | unlock_device_hotplug(); |
1959 | return ret ? ret : count; | |
1960 | } | |
1961 | ||
98f8cdce TG |
1962 | static ssize_t show_cpuhp_target(struct device *dev, |
1963 | struct device_attribute *attr, char *buf) | |
1964 | { | |
1965 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1966 | ||
1967 | return sprintf(buf, "%d\n", st->target); | |
1968 | } | |
757c989b | 1969 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 1970 | |
1db49484 PZ |
1971 | |
1972 | static ssize_t write_cpuhp_fail(struct device *dev, | |
1973 | struct device_attribute *attr, | |
1974 | const char *buf, size_t count) | |
1975 | { | |
1976 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1977 | struct cpuhp_step *sp; | |
1978 | int fail, ret; | |
1979 | ||
1980 | ret = kstrtoint(buf, 10, &fail); | |
1981 | if (ret) | |
1982 | return ret; | |
1983 | ||
33d4a5a7 ET |
1984 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
1985 | return -EINVAL; | |
1986 | ||
1db49484 PZ |
1987 | /* |
1988 | * Cannot fail STARTING/DYING callbacks. | |
1989 | */ | |
1990 | if (cpuhp_is_atomic_state(fail)) | |
1991 | return -EINVAL; | |
1992 | ||
1993 | /* | |
1994 | * Cannot fail anything that doesn't have callbacks. | |
1995 | */ | |
1996 | mutex_lock(&cpuhp_state_mutex); | |
1997 | sp = cpuhp_get_step(fail); | |
1998 | if (!sp->startup.single && !sp->teardown.single) | |
1999 | ret = -EINVAL; | |
2000 | mutex_unlock(&cpuhp_state_mutex); | |
2001 | if (ret) | |
2002 | return ret; | |
2003 | ||
2004 | st->fail = fail; | |
2005 | ||
2006 | return count; | |
2007 | } | |
2008 | ||
2009 | static ssize_t show_cpuhp_fail(struct device *dev, | |
2010 | struct device_attribute *attr, char *buf) | |
2011 | { | |
2012 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2013 | ||
2014 | return sprintf(buf, "%d\n", st->fail); | |
2015 | } | |
2016 | ||
2017 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
2018 | ||
98f8cdce TG |
2019 | static struct attribute *cpuhp_cpu_attrs[] = { |
2020 | &dev_attr_state.attr, | |
2021 | &dev_attr_target.attr, | |
1db49484 | 2022 | &dev_attr_fail.attr, |
98f8cdce TG |
2023 | NULL |
2024 | }; | |
2025 | ||
993647a2 | 2026 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2027 | .attrs = cpuhp_cpu_attrs, |
2028 | .name = "hotplug", | |
2029 | NULL | |
2030 | }; | |
2031 | ||
2032 | static ssize_t show_cpuhp_states(struct device *dev, | |
2033 | struct device_attribute *attr, char *buf) | |
2034 | { | |
2035 | ssize_t cur, res = 0; | |
2036 | int i; | |
2037 | ||
2038 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2039 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2040 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2041 | ||
2042 | if (sp->name) { | |
2043 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2044 | buf += cur; | |
2045 | res += cur; | |
2046 | } | |
2047 | } | |
2048 | mutex_unlock(&cpuhp_state_mutex); | |
2049 | return res; | |
2050 | } | |
2051 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2052 | ||
2053 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2054 | &dev_attr_states.attr, | |
2055 | NULL | |
2056 | }; | |
2057 | ||
993647a2 | 2058 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2059 | .attrs = cpuhp_cpu_root_attrs, |
2060 | .name = "hotplug", | |
2061 | NULL | |
2062 | }; | |
2063 | ||
05736e4a TG |
2064 | #ifdef CONFIG_HOTPLUG_SMT |
2065 | ||
05736e4a TG |
2066 | static void cpuhp_offline_cpu_device(unsigned int cpu) |
2067 | { | |
2068 | struct device *dev = get_cpu_device(cpu); | |
2069 | ||
2070 | dev->offline = true; | |
2071 | /* Tell user space about the state change */ | |
2072 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2073 | } | |
2074 | ||
215af549 TG |
2075 | static void cpuhp_online_cpu_device(unsigned int cpu) |
2076 | { | |
2077 | struct device *dev = get_cpu_device(cpu); | |
2078 | ||
2079 | dev->offline = false; | |
2080 | /* Tell user space about the state change */ | |
2081 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2082 | } | |
2083 | ||
ec527c31 | 2084 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) |
05736e4a TG |
2085 | { |
2086 | int cpu, ret = 0; | |
2087 | ||
2088 | cpu_maps_update_begin(); | |
2089 | for_each_online_cpu(cpu) { | |
2090 | if (topology_is_primary_thread(cpu)) | |
2091 | continue; | |
2092 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2093 | if (ret) | |
2094 | break; | |
2095 | /* | |
2096 | * As this needs to hold the cpu maps lock it's impossible | |
2097 | * to call device_offline() because that ends up calling | |
2098 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2099 | * needs to be held as this might race against in kernel | |
2100 | * abusers of the hotplug machinery (thermal management). | |
2101 | * | |
2102 | * So nothing would update device:offline state. That would | |
2103 | * leave the sysfs entry stale and prevent onlining after | |
2104 | * smt control has been changed to 'off' again. This is | |
2105 | * called under the sysfs hotplug lock, so it is properly | |
2106 | * serialized against the regular offline usage. | |
2107 | */ | |
2108 | cpuhp_offline_cpu_device(cpu); | |
2109 | } | |
34d66caf | 2110 | if (!ret) |
05736e4a TG |
2111 | cpu_smt_control = ctrlval; |
2112 | cpu_maps_update_done(); | |
2113 | return ret; | |
2114 | } | |
2115 | ||
ec527c31 | 2116 | int cpuhp_smt_enable(void) |
05736e4a | 2117 | { |
215af549 TG |
2118 | int cpu, ret = 0; |
2119 | ||
05736e4a TG |
2120 | cpu_maps_update_begin(); |
2121 | cpu_smt_control = CPU_SMT_ENABLED; | |
215af549 TG |
2122 | for_each_present_cpu(cpu) { |
2123 | /* Skip online CPUs and CPUs on offline nodes */ | |
2124 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2125 | continue; | |
2126 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2127 | if (ret) | |
2128 | break; | |
2129 | /* See comment in cpuhp_smt_disable() */ | |
2130 | cpuhp_online_cpu_device(cpu); | |
2131 | } | |
05736e4a | 2132 | cpu_maps_update_done(); |
215af549 | 2133 | return ret; |
05736e4a TG |
2134 | } |
2135 | ||
de7b77e5 | 2136 | |
05736e4a | 2137 | static ssize_t |
de7b77e5 JP |
2138 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2139 | const char *buf, size_t count) | |
05736e4a TG |
2140 | { |
2141 | int ctrlval, ret; | |
2142 | ||
2143 | if (sysfs_streq(buf, "on")) | |
2144 | ctrlval = CPU_SMT_ENABLED; | |
2145 | else if (sysfs_streq(buf, "off")) | |
2146 | ctrlval = CPU_SMT_DISABLED; | |
2147 | else if (sysfs_streq(buf, "forceoff")) | |
2148 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2149 | else | |
2150 | return -EINVAL; | |
2151 | ||
2152 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2153 | return -EPERM; | |
2154 | ||
2155 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2156 | return -ENODEV; | |
2157 | ||
2158 | ret = lock_device_hotplug_sysfs(); | |
2159 | if (ret) | |
2160 | return ret; | |
2161 | ||
2162 | if (ctrlval != cpu_smt_control) { | |
2163 | switch (ctrlval) { | |
2164 | case CPU_SMT_ENABLED: | |
215af549 | 2165 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2166 | break; |
2167 | case CPU_SMT_DISABLED: | |
2168 | case CPU_SMT_FORCE_DISABLED: | |
2169 | ret = cpuhp_smt_disable(ctrlval); | |
2170 | break; | |
2171 | } | |
2172 | } | |
2173 | ||
2174 | unlock_device_hotplug(); | |
2175 | return ret ? ret : count; | |
2176 | } | |
de7b77e5 JP |
2177 | |
2178 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2179 | static ssize_t | |
2180 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2181 | const char *buf, size_t count) | |
2182 | { | |
2183 | return -ENODEV; | |
2184 | } | |
2185 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2186 | ||
2187 | static const char *smt_states[] = { | |
2188 | [CPU_SMT_ENABLED] = "on", | |
2189 | [CPU_SMT_DISABLED] = "off", | |
2190 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2191 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2192 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2193 | }; | |
2194 | ||
2195 | static ssize_t | |
2196 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2197 | { | |
2198 | const char *state = smt_states[cpu_smt_control]; | |
2199 | ||
2200 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2201 | } | |
2202 | ||
2203 | static ssize_t | |
2204 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2205 | const char *buf, size_t count) | |
2206 | { | |
2207 | return __store_smt_control(dev, attr, buf, count); | |
2208 | } | |
05736e4a TG |
2209 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
2210 | ||
2211 | static ssize_t | |
2212 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2213 | { | |
de7b77e5 | 2214 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a TG |
2215 | } |
2216 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2217 | ||
2218 | static struct attribute *cpuhp_smt_attrs[] = { | |
2219 | &dev_attr_control.attr, | |
2220 | &dev_attr_active.attr, | |
2221 | NULL | |
2222 | }; | |
2223 | ||
2224 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2225 | .attrs = cpuhp_smt_attrs, | |
2226 | .name = "smt", | |
2227 | NULL | |
2228 | }; | |
2229 | ||
de7b77e5 | 2230 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2231 | { |
05736e4a TG |
2232 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2233 | &cpuhp_smt_attr_group); | |
2234 | } | |
2235 | ||
98f8cdce TG |
2236 | static int __init cpuhp_sysfs_init(void) |
2237 | { | |
2238 | int cpu, ret; | |
2239 | ||
de7b77e5 | 2240 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2241 | if (ret) |
2242 | return ret; | |
2243 | ||
98f8cdce TG |
2244 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2245 | &cpuhp_cpu_root_attr_group); | |
2246 | if (ret) | |
2247 | return ret; | |
2248 | ||
2249 | for_each_possible_cpu(cpu) { | |
2250 | struct device *dev = get_cpu_device(cpu); | |
2251 | ||
2252 | if (!dev) | |
2253 | continue; | |
2254 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2255 | if (ret) | |
2256 | return ret; | |
2257 | } | |
2258 | return 0; | |
2259 | } | |
2260 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2261 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2262 | |
e56b3bc7 LT |
2263 | /* |
2264 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2265 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2266 | * | |
e0b582ec | 2267 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2268 | * mask value that has a single bit set only. |
2269 | */ | |
b8d317d1 | 2270 | |
e56b3bc7 | 2271 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2272 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2273 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2274 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2275 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2276 | |
e56b3bc7 LT |
2277 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2278 | ||
2279 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2280 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2281 | #if BITS_PER_LONG > 32 | |
2282 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2283 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2284 | #endif |
2285 | }; | |
e56b3bc7 | 2286 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2287 | |
2288 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2289 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2290 | |
2291 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2292 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2293 | = {CPU_BITS_ALL}; |
b3199c02 | 2294 | #else |
4b804c85 | 2295 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2296 | #endif |
4b804c85 | 2297 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2298 | |
4b804c85 RV |
2299 | struct cpumask __cpu_online_mask __read_mostly; |
2300 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2301 | |
4b804c85 RV |
2302 | struct cpumask __cpu_present_mask __read_mostly; |
2303 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2304 | |
4b804c85 RV |
2305 | struct cpumask __cpu_active_mask __read_mostly; |
2306 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2307 | |
0c09ab96 TG |
2308 | atomic_t __num_online_cpus __read_mostly; |
2309 | EXPORT_SYMBOL(__num_online_cpus); | |
2310 | ||
3fa41520 RR |
2311 | void init_cpu_present(const struct cpumask *src) |
2312 | { | |
c4c54dd1 | 2313 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2314 | } |
2315 | ||
2316 | void init_cpu_possible(const struct cpumask *src) | |
2317 | { | |
c4c54dd1 | 2318 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2319 | } |
2320 | ||
2321 | void init_cpu_online(const struct cpumask *src) | |
2322 | { | |
c4c54dd1 | 2323 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2324 | } |
cff7d378 | 2325 | |
0c09ab96 TG |
2326 | void set_cpu_online(unsigned int cpu, bool online) |
2327 | { | |
2328 | /* | |
2329 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2330 | * function by the reboot and kexec code which invoke it from | |
2331 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2332 | * regular CPU hotplug is properly serialized. | |
2333 | * | |
2334 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2335 | * does not protect readers which are not serialized against | |
2336 | * concurrent hotplug operations. | |
2337 | */ | |
2338 | if (online) { | |
2339 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2340 | atomic_inc(&__num_online_cpus); | |
2341 | } else { | |
2342 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2343 | atomic_dec(&__num_online_cpus); | |
2344 | } | |
2345 | } | |
2346 | ||
cff7d378 TG |
2347 | /* |
2348 | * Activate the first processor. | |
2349 | */ | |
2350 | void __init boot_cpu_init(void) | |
2351 | { | |
2352 | int cpu = smp_processor_id(); | |
2353 | ||
2354 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2355 | set_cpu_online(cpu, true); | |
2356 | set_cpu_active(cpu, true); | |
2357 | set_cpu_present(cpu, true); | |
2358 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2359 | |
2360 | #ifdef CONFIG_SMP | |
2361 | __boot_cpu_id = cpu; | |
2362 | #endif | |
cff7d378 TG |
2363 | } |
2364 | ||
2365 | /* | |
2366 | * Must be called _AFTER_ setting up the per_cpu areas | |
2367 | */ | |
b5b1404d | 2368 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2369 | { |
269777aa | 2370 | #ifdef CONFIG_SMP |
e797bda3 | 2371 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2372 | #endif |
0cc3cd21 | 2373 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2374 | } |
98af8452 JP |
2375 | |
2376 | enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO; | |
2377 | ||
2378 | static int __init mitigations_parse_cmdline(char *arg) | |
2379 | { | |
2380 | if (!strcmp(arg, "off")) | |
2381 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2382 | else if (!strcmp(arg, "auto")) | |
2383 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2384 | else if (!strcmp(arg, "auto,nosmt")) | |
2385 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2386 | else |
2387 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2388 | arg); | |
98af8452 JP |
2389 | |
2390 | return 0; | |
2391 | } | |
2392 | early_param("mitigations", mitigations_parse_cmdline); |