Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* CPU control. |
2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell | |
3 | * | |
4 | * This code is licenced under the GPL. | |
5 | */ | |
6 | #include <linux/proc_fs.h> | |
7 | #include <linux/smp.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/notifier.h> | |
3f07c014 | 10 | #include <linux/sched/signal.h> |
ef8bd77f | 11 | #include <linux/sched/hotplug.h> |
9ca12ac0 | 12 | #include <linux/sched/isolation.h> |
29930025 | 13 | #include <linux/sched/task.h> |
a74cfffb | 14 | #include <linux/sched/smt.h> |
1da177e4 LT |
15 | #include <linux/unistd.h> |
16 | #include <linux/cpu.h> | |
cb79295e AV |
17 | #include <linux/oom.h> |
18 | #include <linux/rcupdate.h> | |
9984de1a | 19 | #include <linux/export.h> |
e4cc2f87 | 20 | #include <linux/bug.h> |
1da177e4 LT |
21 | #include <linux/kthread.h> |
22 | #include <linux/stop_machine.h> | |
81615b62 | 23 | #include <linux/mutex.h> |
5a0e3ad6 | 24 | #include <linux/gfp.h> |
79cfbdfa | 25 | #include <linux/suspend.h> |
a19423b9 | 26 | #include <linux/lockdep.h> |
345527b1 | 27 | #include <linux/tick.h> |
a8994181 | 28 | #include <linux/irq.h> |
941154bd | 29 | #include <linux/nmi.h> |
4cb28ced | 30 | #include <linux/smpboot.h> |
e6d4989a | 31 | #include <linux/relay.h> |
6731d4f1 | 32 | #include <linux/slab.h> |
fc8dffd3 | 33 | #include <linux/percpu-rwsem.h> |
cff7d378 | 34 | |
bb3632c6 | 35 | #include <trace/events/power.h> |
cff7d378 TG |
36 | #define CREATE_TRACE_POINTS |
37 | #include <trace/events/cpuhp.h> | |
1da177e4 | 38 | |
38498a67 TG |
39 | #include "smpboot.h" |
40 | ||
cff7d378 TG |
41 | /** |
42 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
43 | * @state: The current cpu state | |
44 | * @target: The target state | |
4cb28ced TG |
45 | * @thread: Pointer to the hotplug thread |
46 | * @should_run: Thread should execute | |
3b9d6da6 | 47 | * @rollback: Perform a rollback |
a724632c TG |
48 | * @single: Single callback invocation |
49 | * @bringup: Single callback bringup or teardown selector | |
50 | * @cb_state: The state for a single callback (install/uninstall) | |
4cb28ced | 51 | * @result: Result of the operation |
5ebe7742 PZ |
52 | * @done_up: Signal completion to the issuer of the task for cpu-up |
53 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
54 | */ |
55 | struct cpuhp_cpu_state { | |
56 | enum cpuhp_state state; | |
57 | enum cpuhp_state target; | |
1db49484 | 58 | enum cpuhp_state fail; |
4cb28ced TG |
59 | #ifdef CONFIG_SMP |
60 | struct task_struct *thread; | |
61 | bool should_run; | |
3b9d6da6 | 62 | bool rollback; |
a724632c TG |
63 | bool single; |
64 | bool bringup; | |
cf392d10 | 65 | struct hlist_node *node; |
4dddfb5f | 66 | struct hlist_node *last; |
4cb28ced | 67 | enum cpuhp_state cb_state; |
4cb28ced | 68 | int result; |
5ebe7742 PZ |
69 | struct completion done_up; |
70 | struct completion done_down; | |
4cb28ced | 71 | #endif |
cff7d378 TG |
72 | }; |
73 | ||
1db49484 PZ |
74 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
75 | .fail = CPUHP_INVALID, | |
76 | }; | |
cff7d378 | 77 | |
e797bda3 TG |
78 | #ifdef CONFIG_SMP |
79 | cpumask_t cpus_booted_once_mask; | |
80 | #endif | |
81 | ||
49dfe2a6 | 82 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
83 | static struct lockdep_map cpuhp_state_up_map = |
84 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
85 | static struct lockdep_map cpuhp_state_down_map = | |
86 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
87 | ||
88 | ||
76dc6c09 | 89 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
90 | { |
91 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
92 | } | |
93 | ||
76dc6c09 | 94 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
95 | { |
96 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
97 | } | |
98 | #else | |
99 | ||
76dc6c09 MM |
100 | static inline void cpuhp_lock_acquire(bool bringup) { } |
101 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 102 | |
49dfe2a6 TG |
103 | #endif |
104 | ||
cff7d378 TG |
105 | /** |
106 | * cpuhp_step - Hotplug state machine step | |
107 | * @name: Name of the step | |
108 | * @startup: Startup function of the step | |
109 | * @teardown: Teardown function of the step | |
757c989b | 110 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
111 | */ |
112 | struct cpuhp_step { | |
cf392d10 TG |
113 | const char *name; |
114 | union { | |
3c1627e9 TG |
115 | int (*single)(unsigned int cpu); |
116 | int (*multi)(unsigned int cpu, | |
117 | struct hlist_node *node); | |
118 | } startup; | |
cf392d10 | 119 | union { |
3c1627e9 TG |
120 | int (*single)(unsigned int cpu); |
121 | int (*multi)(unsigned int cpu, | |
122 | struct hlist_node *node); | |
123 | } teardown; | |
cf392d10 | 124 | struct hlist_head list; |
cf392d10 TG |
125 | bool cant_stop; |
126 | bool multi_instance; | |
cff7d378 TG |
127 | }; |
128 | ||
98f8cdce | 129 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 130 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 131 | |
a724632c TG |
132 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
133 | { | |
17a2f1ce | 134 | return cpuhp_hp_states + state; |
a724632c TG |
135 | } |
136 | ||
cff7d378 TG |
137 | /** |
138 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
139 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 140 | * @state: The state to do callbacks for |
a724632c | 141 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
142 | * @node: For multi-instance, do a single entry callback for install/remove |
143 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 144 | * |
cf392d10 | 145 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 146 | */ |
a724632c | 147 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
148 | bool bringup, struct hlist_node *node, |
149 | struct hlist_node **lastp) | |
cff7d378 TG |
150 | { |
151 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 152 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
153 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
154 | int (*cb)(unsigned int cpu); | |
155 | int ret, cnt; | |
156 | ||
1db49484 PZ |
157 | if (st->fail == state) { |
158 | st->fail = CPUHP_INVALID; | |
159 | ||
160 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
161 | return 0; | |
162 | ||
163 | return -EAGAIN; | |
164 | } | |
165 | ||
cf392d10 | 166 | if (!step->multi_instance) { |
96abb968 | 167 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 168 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
169 | if (!cb) |
170 | return 0; | |
a724632c | 171 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 172 | ret = cb(cpu); |
a724632c | 173 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
174 | return ret; |
175 | } | |
3c1627e9 | 176 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
177 | if (!cbm) |
178 | return 0; | |
179 | ||
180 | /* Single invocation for instance add/remove */ | |
181 | if (node) { | |
96abb968 | 182 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
183 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
184 | ret = cbm(cpu, node); | |
185 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
186 | return ret; | |
187 | } | |
188 | ||
189 | /* State transition. Invoke on all instances */ | |
190 | cnt = 0; | |
191 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
192 | if (lastp && node == *lastp) |
193 | break; | |
194 | ||
cf392d10 TG |
195 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
196 | ret = cbm(cpu, node); | |
197 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
198 | if (ret) { |
199 | if (!lastp) | |
200 | goto err; | |
201 | ||
202 | *lastp = node; | |
203 | return ret; | |
204 | } | |
cf392d10 TG |
205 | cnt++; |
206 | } | |
96abb968 PZ |
207 | if (lastp) |
208 | *lastp = NULL; | |
cf392d10 TG |
209 | return 0; |
210 | err: | |
211 | /* Rollback the instances if one failed */ | |
3c1627e9 | 212 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
213 | if (!cbm) |
214 | return ret; | |
215 | ||
216 | hlist_for_each(node, &step->list) { | |
217 | if (!cnt--) | |
218 | break; | |
724a8688 PZ |
219 | |
220 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
221 | ret = cbm(cpu, node); | |
222 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
223 | /* | |
224 | * Rollback must not fail, | |
225 | */ | |
226 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
227 | } |
228 | return ret; | |
229 | } | |
230 | ||
98a79d6a | 231 | #ifdef CONFIG_SMP |
fcb3029a AB |
232 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
233 | { | |
234 | /* | |
235 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
236 | * purposes as that state is handled explicitly in cpu_down. | |
237 | */ | |
238 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
239 | } | |
240 | ||
5ebe7742 PZ |
241 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
242 | { | |
243 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
244 | wait_for_completion(done); | |
245 | } | |
246 | ||
247 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
248 | { | |
249 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
250 | complete(done); | |
251 | } | |
252 | ||
253 | /* | |
254 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
255 | */ | |
256 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
257 | { | |
258 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
259 | } | |
260 | ||
b3199c02 | 261 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 262 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
263 | bool cpuhp_tasks_frozen; |
264 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 265 | |
79a6cdeb | 266 | /* |
93ae4f97 SB |
267 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
268 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
269 | */ |
270 | void cpu_maps_update_begin(void) | |
271 | { | |
272 | mutex_lock(&cpu_add_remove_lock); | |
273 | } | |
274 | ||
275 | void cpu_maps_update_done(void) | |
276 | { | |
277 | mutex_unlock(&cpu_add_remove_lock); | |
278 | } | |
1da177e4 | 279 | |
fc8dffd3 TG |
280 | /* |
281 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
282 | * Should always be manipulated under cpu_add_remove_lock |
283 | */ | |
284 | static int cpu_hotplug_disabled; | |
285 | ||
79a6cdeb LJ |
286 | #ifdef CONFIG_HOTPLUG_CPU |
287 | ||
fc8dffd3 | 288 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 289 | |
8f553c49 | 290 | void cpus_read_lock(void) |
a9d9baa1 | 291 | { |
fc8dffd3 | 292 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 293 | } |
8f553c49 | 294 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 295 | |
6f4ceee9 WL |
296 | int cpus_read_trylock(void) |
297 | { | |
298 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
299 | } | |
300 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
301 | ||
8f553c49 | 302 | void cpus_read_unlock(void) |
a9d9baa1 | 303 | { |
fc8dffd3 | 304 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 305 | } |
8f553c49 | 306 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 307 | |
8f553c49 | 308 | void cpus_write_lock(void) |
d221938c | 309 | { |
fc8dffd3 | 310 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 311 | } |
87af9e7f | 312 | |
8f553c49 | 313 | void cpus_write_unlock(void) |
d221938c | 314 | { |
fc8dffd3 | 315 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
316 | } |
317 | ||
fc8dffd3 | 318 | void lockdep_assert_cpus_held(void) |
d221938c | 319 | { |
ce48c457 VS |
320 | /* |
321 | * We can't have hotplug operations before userspace starts running, | |
322 | * and some init codepaths will knowingly not take the hotplug lock. | |
323 | * This is all valid, so mute lockdep until it makes sense to report | |
324 | * unheld locks. | |
325 | */ | |
326 | if (system_state < SYSTEM_RUNNING) | |
327 | return; | |
328 | ||
fc8dffd3 | 329 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 330 | } |
79a6cdeb | 331 | |
cb92173d PZ |
332 | static void lockdep_acquire_cpus_lock(void) |
333 | { | |
334 | rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_); | |
335 | } | |
336 | ||
337 | static void lockdep_release_cpus_lock(void) | |
338 | { | |
5facae4f | 339 | rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, _THIS_IP_); |
cb92173d PZ |
340 | } |
341 | ||
16e53dbf SB |
342 | /* |
343 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
344 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
345 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
346 | * hotplug path before performing hotplug operations. So acquiring that lock | |
347 | * guarantees mutual exclusion from any currently running hotplug operations. | |
348 | */ | |
349 | void cpu_hotplug_disable(void) | |
350 | { | |
351 | cpu_maps_update_begin(); | |
89af7ba5 | 352 | cpu_hotplug_disabled++; |
16e53dbf SB |
353 | cpu_maps_update_done(); |
354 | } | |
32145c46 | 355 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 356 | |
01b41159 LW |
357 | static void __cpu_hotplug_enable(void) |
358 | { | |
359 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
360 | return; | |
361 | cpu_hotplug_disabled--; | |
362 | } | |
363 | ||
16e53dbf SB |
364 | void cpu_hotplug_enable(void) |
365 | { | |
366 | cpu_maps_update_begin(); | |
01b41159 | 367 | __cpu_hotplug_enable(); |
16e53dbf SB |
368 | cpu_maps_update_done(); |
369 | } | |
32145c46 | 370 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
371 | |
372 | #else | |
373 | ||
374 | static void lockdep_acquire_cpus_lock(void) | |
375 | { | |
376 | } | |
377 | ||
378 | static void lockdep_release_cpus_lock(void) | |
379 | { | |
380 | } | |
381 | ||
b9d10be7 | 382 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 383 | |
a74cfffb TG |
384 | /* |
385 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
386 | * should override this. | |
387 | */ | |
388 | void __weak arch_smt_update(void) { } | |
389 | ||
0cc3cd21 TG |
390 | #ifdef CONFIG_HOTPLUG_SMT |
391 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 392 | |
8e1b706b | 393 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 394 | { |
e1572f1d | 395 | if (!cpu_smt_possible()) |
8e1b706b JK |
396 | return; |
397 | ||
398 | if (force) { | |
0cc3cd21 TG |
399 | pr_info("SMT: Force disabled\n"); |
400 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 401 | } else { |
d0e7d144 | 402 | pr_info("SMT: disabled\n"); |
8e1b706b | 403 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 404 | } |
8e1b706b JK |
405 | } |
406 | ||
fee0aede TG |
407 | /* |
408 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 409 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
410 | */ |
411 | void __init cpu_smt_check_topology(void) | |
412 | { | |
b284909a | 413 | if (!topology_smt_supported()) |
bc2d8d26 TG |
414 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
415 | } | |
416 | ||
8e1b706b JK |
417 | static int __init smt_cmdline_disable(char *str) |
418 | { | |
419 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
420 | return 0; |
421 | } | |
422 | early_param("nosmt", smt_cmdline_disable); | |
423 | ||
424 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
425 | { | |
b284909a | 426 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
427 | return true; |
428 | ||
b284909a | 429 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
430 | return true; |
431 | ||
432 | /* | |
433 | * On x86 it's required to boot all logical CPUs at least once so | |
434 | * that the init code can get a chance to set CR4.MCE on each | |
435 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any | |
436 | * core will shutdown the machine. | |
437 | */ | |
e797bda3 | 438 | return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); |
0cc3cd21 | 439 | } |
e1572f1d VK |
440 | |
441 | /* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ | |
442 | bool cpu_smt_possible(void) | |
443 | { | |
444 | return cpu_smt_control != CPU_SMT_FORCE_DISABLED && | |
445 | cpu_smt_control != CPU_SMT_NOT_SUPPORTED; | |
446 | } | |
447 | EXPORT_SYMBOL_GPL(cpu_smt_possible); | |
0cc3cd21 TG |
448 | #else |
449 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
450 | #endif | |
451 | ||
4dddfb5f PZ |
452 | static inline enum cpuhp_state |
453 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
454 | { | |
455 | enum cpuhp_state prev_state = st->state; | |
456 | ||
457 | st->rollback = false; | |
458 | st->last = NULL; | |
459 | ||
460 | st->target = target; | |
461 | st->single = false; | |
462 | st->bringup = st->state < target; | |
463 | ||
464 | return prev_state; | |
465 | } | |
466 | ||
467 | static inline void | |
468 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
469 | { | |
470 | st->rollback = true; | |
471 | ||
472 | /* | |
473 | * If we have st->last we need to undo partial multi_instance of this | |
474 | * state first. Otherwise start undo at the previous state. | |
475 | */ | |
476 | if (!st->last) { | |
477 | if (st->bringup) | |
478 | st->state--; | |
479 | else | |
480 | st->state++; | |
481 | } | |
482 | ||
483 | st->target = prev_state; | |
484 | st->bringup = !st->bringup; | |
485 | } | |
486 | ||
487 | /* Regular hotplug invocation of the AP hotplug thread */ | |
488 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
489 | { | |
490 | if (!st->single && st->state == st->target) | |
491 | return; | |
492 | ||
493 | st->result = 0; | |
494 | /* | |
495 | * Make sure the above stores are visible before should_run becomes | |
496 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
497 | */ | |
498 | smp_mb(); | |
499 | st->should_run = true; | |
500 | wake_up_process(st->thread); | |
5ebe7742 | 501 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
502 | } |
503 | ||
504 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
505 | { | |
506 | enum cpuhp_state prev_state; | |
507 | int ret; | |
508 | ||
509 | prev_state = cpuhp_set_state(st, target); | |
510 | __cpuhp_kick_ap(st); | |
511 | if ((ret = st->result)) { | |
512 | cpuhp_reset_state(st, prev_state); | |
513 | __cpuhp_kick_ap(st); | |
514 | } | |
515 | ||
516 | return ret; | |
517 | } | |
9cd4f1a4 | 518 | |
8df3e07e TG |
519 | static int bringup_wait_for_ap(unsigned int cpu) |
520 | { | |
521 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
522 | ||
9cd4f1a4 | 523 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 524 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
525 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
526 | return -ECANCELED; | |
9cd4f1a4 | 527 | |
45178ac0 | 528 | /* Unpark the hotplug thread of the target cpu */ |
9cd4f1a4 TG |
529 | kthread_unpark(st->thread); |
530 | ||
0cc3cd21 TG |
531 | /* |
532 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
533 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 534 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
535 | * cpu_smt_allowed() check will now return false if this is not the |
536 | * primary sibling. | |
537 | */ | |
538 | if (!cpu_smt_allowed(cpu)) | |
539 | return -ECANCELED; | |
540 | ||
4dddfb5f PZ |
541 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
542 | return 0; | |
543 | ||
544 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
545 | } |
546 | ||
ba997462 TG |
547 | static int bringup_cpu(unsigned int cpu) |
548 | { | |
549 | struct task_struct *idle = idle_thread_get(cpu); | |
550 | int ret; | |
551 | ||
aa877175 BO |
552 | /* |
553 | * Some architectures have to walk the irq descriptors to | |
554 | * setup the vector space for the cpu which comes online. | |
555 | * Prevent irq alloc/free across the bringup. | |
556 | */ | |
557 | irq_lock_sparse(); | |
558 | ||
ba997462 TG |
559 | /* Arch-specific enabling code. */ |
560 | ret = __cpu_up(cpu, idle); | |
aa877175 | 561 | irq_unlock_sparse(); |
530e9b76 | 562 | if (ret) |
ba997462 | 563 | return ret; |
9cd4f1a4 | 564 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
565 | } |
566 | ||
2e1a3483 TG |
567 | /* |
568 | * Hotplug state machine related functions | |
569 | */ | |
2e1a3483 | 570 | |
a724632c | 571 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 | 572 | { |
6fb86d97 MO |
573 | for (st->state--; st->state > st->target; st->state--) |
574 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
2e1a3483 TG |
575 | } |
576 | ||
206b9235 TG |
577 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
578 | { | |
579 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
580 | return true; | |
581 | /* | |
582 | * When CPU hotplug is disabled, then taking the CPU down is not | |
583 | * possible because takedown_cpu() and the architecture and | |
584 | * subsystem specific mechanisms are not available. So the CPU | |
585 | * which would be completely unplugged again needs to stay around | |
586 | * in the current state. | |
587 | */ | |
588 | return st->state <= CPUHP_BRINGUP_CPU; | |
589 | } | |
590 | ||
2e1a3483 | 591 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 592 | enum cpuhp_state target) |
2e1a3483 TG |
593 | { |
594 | enum cpuhp_state prev_state = st->state; | |
595 | int ret = 0; | |
596 | ||
597 | while (st->state < target) { | |
2e1a3483 | 598 | st->state++; |
96abb968 | 599 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 | 600 | if (ret) { |
206b9235 TG |
601 | if (can_rollback_cpu(st)) { |
602 | st->target = prev_state; | |
603 | undo_cpu_up(cpu, st); | |
604 | } | |
2e1a3483 TG |
605 | break; |
606 | } | |
607 | } | |
608 | return ret; | |
609 | } | |
610 | ||
4cb28ced TG |
611 | /* |
612 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
613 | */ | |
614 | static void cpuhp_create(unsigned int cpu) | |
615 | { | |
616 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
617 | ||
5ebe7742 PZ |
618 | init_completion(&st->done_up); |
619 | init_completion(&st->done_down); | |
4cb28ced TG |
620 | } |
621 | ||
622 | static int cpuhp_should_run(unsigned int cpu) | |
623 | { | |
624 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
625 | ||
626 | return st->should_run; | |
627 | } | |
628 | ||
4cb28ced TG |
629 | /* |
630 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
631 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
632 | * |
633 | * Each invocation of this function by the smpboot thread does a single AP | |
634 | * state callback. | |
635 | * | |
636 | * It has 3 modes of operation: | |
637 | * - single: runs st->cb_state | |
638 | * - up: runs ++st->state, while st->state < st->target | |
639 | * - down: runs st->state--, while st->state > st->target | |
640 | * | |
641 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
642 | */ |
643 | static void cpuhp_thread_fun(unsigned int cpu) | |
644 | { | |
645 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
646 | bool bringup = st->bringup; |
647 | enum cpuhp_state state; | |
4cb28ced | 648 | |
f8b7530a NU |
649 | if (WARN_ON_ONCE(!st->should_run)) |
650 | return; | |
651 | ||
4cb28ced | 652 | /* |
4dddfb5f PZ |
653 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
654 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
655 | */ |
656 | smp_mb(); | |
4cb28ced | 657 | |
cb92173d PZ |
658 | /* |
659 | * The BP holds the hotplug lock, but we're now running on the AP, | |
660 | * ensure that anybody asserting the lock is held, will actually find | |
661 | * it so. | |
662 | */ | |
663 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 664 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 665 | |
a724632c | 666 | if (st->single) { |
4dddfb5f PZ |
667 | state = st->cb_state; |
668 | st->should_run = false; | |
669 | } else { | |
670 | if (bringup) { | |
671 | st->state++; | |
672 | state = st->state; | |
673 | st->should_run = (st->state < st->target); | |
674 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 675 | } else { |
4dddfb5f PZ |
676 | state = st->state; |
677 | st->state--; | |
678 | st->should_run = (st->state > st->target); | |
679 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 680 | } |
4dddfb5f PZ |
681 | } |
682 | ||
683 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
684 | ||
4dddfb5f PZ |
685 | if (cpuhp_is_atomic_state(state)) { |
686 | local_irq_disable(); | |
687 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
688 | local_irq_enable(); | |
3b9d6da6 | 689 | |
4dddfb5f PZ |
690 | /* |
691 | * STARTING/DYING must not fail! | |
692 | */ | |
693 | WARN_ON_ONCE(st->result); | |
4cb28ced | 694 | } else { |
4dddfb5f PZ |
695 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
696 | } | |
697 | ||
698 | if (st->result) { | |
699 | /* | |
700 | * If we fail on a rollback, we're up a creek without no | |
701 | * paddle, no way forward, no way back. We loose, thanks for | |
702 | * playing. | |
703 | */ | |
704 | WARN_ON_ONCE(st->rollback); | |
705 | st->should_run = false; | |
4cb28ced | 706 | } |
4dddfb5f | 707 | |
5f4b55e1 | 708 | cpuhp_lock_release(bringup); |
cb92173d | 709 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
710 | |
711 | if (!st->should_run) | |
5ebe7742 | 712 | complete_ap_thread(st, bringup); |
4cb28ced TG |
713 | } |
714 | ||
715 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 716 | static int |
cf392d10 TG |
717 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
718 | struct hlist_node *node) | |
4cb28ced TG |
719 | { |
720 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 721 | int ret; |
4cb28ced TG |
722 | |
723 | if (!cpu_online(cpu)) | |
724 | return 0; | |
725 | ||
5f4b55e1 PZ |
726 | cpuhp_lock_acquire(false); |
727 | cpuhp_lock_release(false); | |
728 | ||
729 | cpuhp_lock_acquire(true); | |
730 | cpuhp_lock_release(true); | |
49dfe2a6 | 731 | |
6a4e2451 TG |
732 | /* |
733 | * If we are up and running, use the hotplug thread. For early calls | |
734 | * we invoke the thread function directly. | |
735 | */ | |
736 | if (!st->thread) | |
96abb968 | 737 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 738 | |
4dddfb5f PZ |
739 | st->rollback = false; |
740 | st->last = NULL; | |
741 | ||
742 | st->node = node; | |
743 | st->bringup = bringup; | |
4cb28ced | 744 | st->cb_state = state; |
a724632c | 745 | st->single = true; |
a724632c | 746 | |
4dddfb5f | 747 | __cpuhp_kick_ap(st); |
4cb28ced | 748 | |
4cb28ced | 749 | /* |
4dddfb5f | 750 | * If we failed and did a partial, do a rollback. |
4cb28ced | 751 | */ |
4dddfb5f PZ |
752 | if ((ret = st->result) && st->last) { |
753 | st->rollback = true; | |
754 | st->bringup = !bringup; | |
755 | ||
756 | __cpuhp_kick_ap(st); | |
757 | } | |
758 | ||
1f7c70d6 TG |
759 | /* |
760 | * Clean up the leftovers so the next hotplug operation wont use stale | |
761 | * data. | |
762 | */ | |
763 | st->node = st->last = NULL; | |
4dddfb5f | 764 | return ret; |
1cf4f629 TG |
765 | } |
766 | ||
767 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
768 | { | |
769 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
770 | enum cpuhp_state prev_state = st->state; |
771 | int ret; | |
1cf4f629 | 772 | |
5f4b55e1 PZ |
773 | cpuhp_lock_acquire(false); |
774 | cpuhp_lock_release(false); | |
775 | ||
776 | cpuhp_lock_acquire(true); | |
777 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
778 | |
779 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
780 | ret = cpuhp_kick_ap(st, st->target); | |
781 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
782 | ||
783 | return ret; | |
4cb28ced TG |
784 | } |
785 | ||
786 | static struct smp_hotplug_thread cpuhp_threads = { | |
787 | .store = &cpuhp_state.thread, | |
788 | .create = &cpuhp_create, | |
789 | .thread_should_run = cpuhp_should_run, | |
790 | .thread_fn = cpuhp_thread_fun, | |
791 | .thread_comm = "cpuhp/%u", | |
792 | .selfparking = true, | |
793 | }; | |
794 | ||
795 | void __init cpuhp_threads_init(void) | |
796 | { | |
797 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
798 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
799 | } | |
800 | ||
777c6e0d | 801 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
802 | /** |
803 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
804 | * @cpu: a CPU id | |
805 | * | |
806 | * This function walks all processes, finds a valid mm struct for each one and | |
807 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
808 | * trivial, there are various non-obvious corner cases, which this function | |
809 | * tries to solve in a safe manner. | |
810 | * | |
811 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
812 | * be called only for an already offlined CPU. | |
813 | */ | |
cb79295e AV |
814 | void clear_tasks_mm_cpumask(int cpu) |
815 | { | |
816 | struct task_struct *p; | |
817 | ||
818 | /* | |
819 | * This function is called after the cpu is taken down and marked | |
820 | * offline, so its not like new tasks will ever get this cpu set in | |
821 | * their mm mask. -- Peter Zijlstra | |
822 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
823 | * full-fledged tasklist_lock. | |
824 | */ | |
e4cc2f87 | 825 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
826 | rcu_read_lock(); |
827 | for_each_process(p) { | |
828 | struct task_struct *t; | |
829 | ||
e4cc2f87 AV |
830 | /* |
831 | * Main thread might exit, but other threads may still have | |
832 | * a valid mm. Find one. | |
833 | */ | |
cb79295e AV |
834 | t = find_lock_task_mm(p); |
835 | if (!t) | |
836 | continue; | |
837 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
838 | task_unlock(t); | |
839 | } | |
840 | rcu_read_unlock(); | |
841 | } | |
842 | ||
1da177e4 | 843 | /* Take this CPU down. */ |
71cf5aee | 844 | static int take_cpu_down(void *_param) |
1da177e4 | 845 | { |
4baa0afc TG |
846 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
847 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 848 | int err, cpu = smp_processor_id(); |
724a8688 | 849 | int ret; |
1da177e4 | 850 | |
1da177e4 LT |
851 | /* Ensure this CPU doesn't handle any more interrupts. */ |
852 | err = __cpu_disable(); | |
853 | if (err < 0) | |
f3705136 | 854 | return err; |
1da177e4 | 855 | |
a724632c TG |
856 | /* |
857 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
858 | * do this step again. | |
859 | */ | |
860 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
861 | st->state--; | |
4baa0afc | 862 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
863 | for (; st->state > target; st->state--) { |
864 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
865 | /* | |
866 | * DYING must not fail! | |
867 | */ | |
868 | WARN_ON_ONCE(ret); | |
869 | } | |
4baa0afc | 870 | |
52c063d1 TG |
871 | /* Give up timekeeping duties */ |
872 | tick_handover_do_timer(); | |
1b72d432 TG |
873 | /* Remove CPU from timer broadcasting */ |
874 | tick_offline_cpu(cpu); | |
14e568e7 | 875 | /* Park the stopper thread */ |
090e77c3 | 876 | stop_machine_park(cpu); |
f3705136 | 877 | return 0; |
1da177e4 LT |
878 | } |
879 | ||
98458172 | 880 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 881 | { |
e69aab13 | 882 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 883 | int err; |
1da177e4 | 884 | |
2a58c527 | 885 | /* Park the smpboot threads */ |
1cf4f629 TG |
886 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
887 | ||
6acce3ef | 888 | /* |
a8994181 TG |
889 | * Prevent irq alloc/free while the dying cpu reorganizes the |
890 | * interrupt affinities. | |
6acce3ef | 891 | */ |
a8994181 | 892 | irq_lock_sparse(); |
6acce3ef | 893 | |
a8994181 TG |
894 | /* |
895 | * So now all preempt/rcu users must observe !cpu_active(). | |
896 | */ | |
210e2133 | 897 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 898 | if (err) { |
3b9d6da6 | 899 | /* CPU refused to die */ |
a8994181 | 900 | irq_unlock_sparse(); |
3b9d6da6 SAS |
901 | /* Unpark the hotplug thread so we can rollback there */ |
902 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 903 | return err; |
8fa1d7d3 | 904 | } |
04321587 | 905 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 906 | |
48c5ccae | 907 | /* |
5b1ead68 BJ |
908 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
909 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 910 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
911 | * |
912 | * Wait for the stop thread to go away. | |
48c5ccae | 913 | */ |
5ebe7742 | 914 | wait_for_ap_thread(st, false); |
e69aab13 | 915 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 916 | |
a8994181 TG |
917 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
918 | irq_unlock_sparse(); | |
919 | ||
345527b1 | 920 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
921 | /* This actually kills the CPU. */ |
922 | __cpu_die(cpu); | |
923 | ||
a49b116d | 924 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 925 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
926 | return 0; |
927 | } | |
1da177e4 | 928 | |
71f87b2f TG |
929 | static void cpuhp_complete_idle_dead(void *arg) |
930 | { | |
931 | struct cpuhp_cpu_state *st = arg; | |
932 | ||
5ebe7742 | 933 | complete_ap_thread(st, false); |
71f87b2f TG |
934 | } |
935 | ||
e69aab13 TG |
936 | void cpuhp_report_idle_dead(void) |
937 | { | |
938 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
939 | ||
940 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 941 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
942 | st->state = CPUHP_AP_IDLE_DEAD; |
943 | /* | |
944 | * We cannot call complete after rcu_report_dead() so we delegate it | |
945 | * to an online cpu. | |
946 | */ | |
947 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
948 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
949 | } |
950 | ||
4dddfb5f PZ |
951 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
952 | { | |
6fb86d97 MO |
953 | for (st->state++; st->state < st->target; st->state++) |
954 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
4dddfb5f PZ |
955 | } |
956 | ||
957 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
958 | enum cpuhp_state target) | |
959 | { | |
960 | enum cpuhp_state prev_state = st->state; | |
961 | int ret = 0; | |
962 | ||
963 | for (; st->state > target; st->state--) { | |
964 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
965 | if (ret) { | |
966 | st->target = prev_state; | |
69fa6eb7 TG |
967 | if (st->state < prev_state) |
968 | undo_cpu_down(cpu, st); | |
4dddfb5f PZ |
969 | break; |
970 | } | |
971 | } | |
972 | return ret; | |
973 | } | |
cff7d378 | 974 | |
98458172 | 975 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
976 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
977 | enum cpuhp_state target) | |
98458172 | 978 | { |
cff7d378 TG |
979 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
980 | int prev_state, ret = 0; | |
98458172 TG |
981 | |
982 | if (num_online_cpus() == 1) | |
983 | return -EBUSY; | |
984 | ||
757c989b | 985 | if (!cpu_present(cpu)) |
98458172 TG |
986 | return -EINVAL; |
987 | ||
8f553c49 | 988 | cpus_write_lock(); |
98458172 TG |
989 | |
990 | cpuhp_tasks_frozen = tasks_frozen; | |
991 | ||
4dddfb5f | 992 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
993 | /* |
994 | * If the current CPU state is in the range of the AP hotplug thread, | |
995 | * then we need to kick the thread. | |
996 | */ | |
8df3e07e | 997 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 998 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
999 | ret = cpuhp_kick_ap_work(cpu); |
1000 | /* | |
1001 | * The AP side has done the error rollback already. Just | |
1002 | * return the error code.. | |
1003 | */ | |
1004 | if (ret) | |
1005 | goto out; | |
1006 | ||
1007 | /* | |
1008 | * We might have stopped still in the range of the AP hotplug | |
1009 | * thread. Nothing to do anymore. | |
1010 | */ | |
8df3e07e | 1011 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1012 | goto out; |
4dddfb5f PZ |
1013 | |
1014 | st->target = target; | |
1cf4f629 TG |
1015 | } |
1016 | /* | |
8df3e07e | 1017 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1018 | * to do the further cleanups. |
1019 | */ | |
a724632c | 1020 | ret = cpuhp_down_callbacks(cpu, st, target); |
69fa6eb7 | 1021 | if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
1022 | cpuhp_reset_state(st, prev_state); |
1023 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 1024 | } |
98458172 | 1025 | |
1cf4f629 | 1026 | out: |
8f553c49 | 1027 | cpus_write_unlock(); |
941154bd TG |
1028 | /* |
1029 | * Do post unplug cleanup. This is still protected against | |
1030 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1031 | */ | |
1032 | lockup_detector_cleanup(); | |
a74cfffb | 1033 | arch_smt_update(); |
cff7d378 | 1034 | return ret; |
e3920fb4 RW |
1035 | } |
1036 | ||
cc1fe215 TG |
1037 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1038 | { | |
1039 | if (cpu_hotplug_disabled) | |
1040 | return -EBUSY; | |
1041 | return _cpu_down(cpu, 0, target); | |
1042 | } | |
1043 | ||
af1f4045 | 1044 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1045 | { |
9ea09af3 | 1046 | int err; |
e3920fb4 | 1047 | |
d221938c | 1048 | cpu_maps_update_begin(); |
cc1fe215 | 1049 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1050 | cpu_maps_update_done(); |
1da177e4 LT |
1051 | return err; |
1052 | } | |
4dddfb5f | 1053 | |
af1f4045 TG |
1054 | int cpu_down(unsigned int cpu) |
1055 | { | |
1056 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1057 | } | |
b62b8ef9 | 1058 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f | 1059 | |
93ef1429 QY |
1060 | int remove_cpu(unsigned int cpu) |
1061 | { | |
1062 | int ret; | |
1063 | ||
1064 | lock_device_hotplug(); | |
1065 | ret = device_offline(get_cpu_device(cpu)); | |
1066 | unlock_device_hotplug(); | |
1067 | ||
1068 | return ret; | |
1069 | } | |
1070 | EXPORT_SYMBOL_GPL(remove_cpu); | |
1071 | ||
0441a559 QY |
1072 | void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) |
1073 | { | |
1074 | unsigned int cpu; | |
1075 | int error; | |
1076 | ||
1077 | cpu_maps_update_begin(); | |
1078 | ||
1079 | /* | |
1080 | * Make certain the cpu I'm about to reboot on is online. | |
1081 | * | |
1082 | * This is inline to what migrate_to_reboot_cpu() already do. | |
1083 | */ | |
1084 | if (!cpu_online(primary_cpu)) | |
1085 | primary_cpu = cpumask_first(cpu_online_mask); | |
1086 | ||
1087 | for_each_online_cpu(cpu) { | |
1088 | if (cpu == primary_cpu) | |
1089 | continue; | |
1090 | ||
1091 | error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
1092 | if (error) { | |
1093 | pr_err("Failed to offline CPU%d - error=%d", | |
1094 | cpu, error); | |
1095 | break; | |
1096 | } | |
1097 | } | |
1098 | ||
1099 | /* | |
1100 | * Ensure all but the reboot CPU are offline. | |
1101 | */ | |
1102 | BUG_ON(num_online_cpus() > 1); | |
1103 | ||
1104 | /* | |
1105 | * Make sure the CPUs won't be enabled by someone else after this | |
1106 | * point. Kexec will reboot to a new kernel shortly resetting | |
1107 | * everything along the way. | |
1108 | */ | |
1109 | cpu_hotplug_disabled++; | |
1110 | ||
1111 | cpu_maps_update_done(); | |
1112 | } | |
1113 | ||
4dddfb5f PZ |
1114 | #else |
1115 | #define takedown_cpu NULL | |
1da177e4 LT |
1116 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1117 | ||
4baa0afc | 1118 | /** |
ee1e714b | 1119 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1120 | * @cpu: cpu that just started |
1121 | * | |
4baa0afc TG |
1122 | * It must be called by the arch code on the new cpu, before the new cpu |
1123 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1124 | */ | |
1125 | void notify_cpu_starting(unsigned int cpu) | |
1126 | { | |
1127 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1128 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1129 | int ret; |
4baa0afc | 1130 | |
0c6d4576 | 1131 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1132 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
4baa0afc | 1133 | while (st->state < target) { |
4baa0afc | 1134 | st->state++; |
724a8688 PZ |
1135 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1136 | /* | |
1137 | * STARTING must not fail! | |
1138 | */ | |
1139 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1140 | } |
1141 | } | |
1142 | ||
949338e3 | 1143 | /* |
9cd4f1a4 | 1144 | * Called from the idle task. Wake up the controlling task which brings the |
45178ac0 PZ |
1145 | * hotplug thread of the upcoming CPU up and then delegates the rest of the |
1146 | * online bringup to the hotplug thread. | |
949338e3 | 1147 | */ |
8df3e07e | 1148 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1149 | { |
8df3e07e | 1150 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1151 | |
1152 | /* Happens for the boot cpu */ | |
1153 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1154 | return; | |
1155 | ||
45178ac0 PZ |
1156 | /* |
1157 | * Unpart the stopper thread before we start the idle loop (and start | |
1158 | * scheduling); this ensures the stopper task is always available. | |
1159 | */ | |
1160 | stop_machine_unpark(smp_processor_id()); | |
1161 | ||
8df3e07e | 1162 | st->state = CPUHP_AP_ONLINE_IDLE; |
5ebe7742 | 1163 | complete_ap_thread(st, true); |
949338e3 TG |
1164 | } |
1165 | ||
e3920fb4 | 1166 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1167 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1168 | { |
cff7d378 | 1169 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1170 | struct task_struct *idle; |
2e1a3483 | 1171 | int ret = 0; |
1da177e4 | 1172 | |
8f553c49 | 1173 | cpus_write_lock(); |
38498a67 | 1174 | |
757c989b | 1175 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1176 | ret = -EINVAL; |
1177 | goto out; | |
1178 | } | |
1179 | ||
757c989b TG |
1180 | /* |
1181 | * The caller of do_cpu_up might have raced with another | |
1182 | * caller. Ignore it for now. | |
1183 | */ | |
1184 | if (st->state >= target) | |
38498a67 | 1185 | goto out; |
757c989b TG |
1186 | |
1187 | if (st->state == CPUHP_OFFLINE) { | |
1188 | /* Let it fail before we try to bring the cpu up */ | |
1189 | idle = idle_thread_get(cpu); | |
1190 | if (IS_ERR(idle)) { | |
1191 | ret = PTR_ERR(idle); | |
1192 | goto out; | |
1193 | } | |
3bb5d2ee | 1194 | } |
38498a67 | 1195 | |
ba997462 TG |
1196 | cpuhp_tasks_frozen = tasks_frozen; |
1197 | ||
4dddfb5f | 1198 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1199 | /* |
1200 | * If the current CPU state is in the range of the AP hotplug thread, | |
1201 | * then we need to kick the thread once more. | |
1202 | */ | |
8df3e07e | 1203 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1204 | ret = cpuhp_kick_ap_work(cpu); |
1205 | /* | |
1206 | * The AP side has done the error rollback already. Just | |
1207 | * return the error code.. | |
1208 | */ | |
1209 | if (ret) | |
1210 | goto out; | |
1211 | } | |
1212 | ||
1213 | /* | |
1214 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1215 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1216 | * responsible for bringing it up to the target state. |
1217 | */ | |
8df3e07e | 1218 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1219 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1220 | out: |
8f553c49 | 1221 | cpus_write_unlock(); |
a74cfffb | 1222 | arch_smt_update(); |
e3920fb4 RW |
1223 | return ret; |
1224 | } | |
1225 | ||
af1f4045 | 1226 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1227 | { |
1228 | int err = 0; | |
cf23422b | 1229 | |
e0b582ec | 1230 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1231 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1232 | cpu); | |
87d5e023 | 1233 | #if defined(CONFIG_IA64) |
84117da5 | 1234 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1235 | #endif |
1236 | return -EINVAL; | |
1237 | } | |
e3920fb4 | 1238 | |
01b0f197 TK |
1239 | err = try_online_node(cpu_to_node(cpu)); |
1240 | if (err) | |
1241 | return err; | |
cf23422b | 1242 | |
d221938c | 1243 | cpu_maps_update_begin(); |
e761b772 MK |
1244 | |
1245 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1246 | err = -EBUSY; |
e761b772 MK |
1247 | goto out; |
1248 | } | |
05736e4a TG |
1249 | if (!cpu_smt_allowed(cpu)) { |
1250 | err = -EPERM; | |
1251 | goto out; | |
1252 | } | |
e761b772 | 1253 | |
af1f4045 | 1254 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1255 | out: |
d221938c | 1256 | cpu_maps_update_done(); |
e3920fb4 RW |
1257 | return err; |
1258 | } | |
af1f4045 TG |
1259 | |
1260 | int cpu_up(unsigned int cpu) | |
1261 | { | |
1262 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1263 | } | |
a513f6ba | 1264 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1265 | |
93ef1429 QY |
1266 | int add_cpu(unsigned int cpu) |
1267 | { | |
1268 | int ret; | |
1269 | ||
1270 | lock_device_hotplug(); | |
1271 | ret = device_online(get_cpu_device(cpu)); | |
1272 | unlock_device_hotplug(); | |
1273 | ||
1274 | return ret; | |
1275 | } | |
1276 | EXPORT_SYMBOL_GPL(add_cpu); | |
1277 | ||
d720f986 QY |
1278 | /** |
1279 | * bringup_hibernate_cpu - Bring up the CPU that we hibernated on | |
1280 | * @sleep_cpu: The cpu we hibernated on and should be brought up. | |
1281 | * | |
1282 | * On some architectures like arm64, we can hibernate on any CPU, but on | |
1283 | * wake up the CPU we hibernated on might be offline as a side effect of | |
1284 | * using maxcpus= for example. | |
1285 | */ | |
1286 | int bringup_hibernate_cpu(unsigned int sleep_cpu) | |
1287 | { | |
1288 | int ret; | |
1289 | ||
1290 | if (!cpu_online(sleep_cpu)) { | |
1291 | pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); | |
1292 | ret = cpu_up(sleep_cpu); | |
1293 | if (ret) { | |
1294 | pr_err("Failed to bring hibernate-CPU up!\n"); | |
1295 | return ret; | |
1296 | } | |
1297 | } | |
1298 | return 0; | |
1299 | } | |
1300 | ||
f3de4be9 | 1301 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1302 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1303 | |
d391e552 | 1304 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1305 | { |
d391e552 | 1306 | int cpu, error = 0; |
e3920fb4 | 1307 | |
d221938c | 1308 | cpu_maps_update_begin(); |
9ca12ac0 | 1309 | if (primary == -1) { |
d391e552 | 1310 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1311 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1312 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1313 | } else { | |
1314 | if (!cpu_online(primary)) | |
1315 | primary = cpumask_first(cpu_online_mask); | |
1316 | } | |
1317 | ||
9ee349ad XF |
1318 | /* |
1319 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1320 | * with the userspace trying to use the CPU hotplug at the same time |
1321 | */ | |
e0b582ec | 1322 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1323 | |
84117da5 | 1324 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1325 | for_each_online_cpu(cpu) { |
d391e552 | 1326 | if (cpu == primary) |
e3920fb4 | 1327 | continue; |
a66d955e PK |
1328 | |
1329 | if (pm_wakeup_pending()) { | |
1330 | pr_info("Wakeup pending. Abort CPU freeze\n"); | |
1331 | error = -EBUSY; | |
1332 | break; | |
1333 | } | |
1334 | ||
bb3632c6 | 1335 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1336 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1337 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1338 | if (!error) |
e0b582ec | 1339 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1340 | else { |
84117da5 | 1341 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1342 | break; |
1343 | } | |
1344 | } | |
86886e55 | 1345 | |
89af7ba5 | 1346 | if (!error) |
e3920fb4 | 1347 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1348 | else |
84117da5 | 1349 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1350 | |
1351 | /* | |
1352 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1353 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1354 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1355 | */ | |
1356 | cpu_hotplug_disabled++; | |
1357 | ||
d221938c | 1358 | cpu_maps_update_done(); |
e3920fb4 RW |
1359 | return error; |
1360 | } | |
1361 | ||
d0af9eed SS |
1362 | void __weak arch_enable_nonboot_cpus_begin(void) |
1363 | { | |
1364 | } | |
1365 | ||
1366 | void __weak arch_enable_nonboot_cpus_end(void) | |
1367 | { | |
1368 | } | |
1369 | ||
71cf5aee | 1370 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1371 | { |
1372 | int cpu, error; | |
1373 | ||
1374 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1375 | cpu_maps_update_begin(); |
01b41159 | 1376 | __cpu_hotplug_enable(); |
e0b582ec | 1377 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1378 | goto out; |
e3920fb4 | 1379 | |
84117da5 | 1380 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1381 | |
1382 | arch_enable_nonboot_cpus_begin(); | |
1383 | ||
e0b582ec | 1384 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1385 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1386 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1387 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1388 | if (!error) { |
84117da5 | 1389 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1390 | continue; |
1391 | } | |
84117da5 | 1392 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1393 | } |
d0af9eed SS |
1394 | |
1395 | arch_enable_nonboot_cpus_end(); | |
1396 | ||
e0b582ec | 1397 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1398 | out: |
d221938c | 1399 | cpu_maps_update_done(); |
1da177e4 | 1400 | } |
e0b582ec | 1401 | |
d7268a31 | 1402 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1403 | { |
1404 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1405 | return -ENOMEM; | |
1406 | return 0; | |
1407 | } | |
1408 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1409 | |
79cfbdfa SB |
1410 | /* |
1411 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1412 | * ensure that the state of the system with respect to the tasks being frozen | |
1413 | * or not, as reported by the notification, remains unchanged *throughout the | |
1414 | * duration* of the execution of the callbacks. | |
1415 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1416 | * | |
1417 | * This synchronization is implemented by mutually excluding regular CPU | |
1418 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1419 | * Hibernate notifications. | |
1420 | */ | |
1421 | static int | |
1422 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1423 | unsigned long action, void *ptr) | |
1424 | { | |
1425 | switch (action) { | |
1426 | ||
1427 | case PM_SUSPEND_PREPARE: | |
1428 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1429 | cpu_hotplug_disable(); |
79cfbdfa SB |
1430 | break; |
1431 | ||
1432 | case PM_POST_SUSPEND: | |
1433 | case PM_POST_HIBERNATION: | |
16e53dbf | 1434 | cpu_hotplug_enable(); |
79cfbdfa SB |
1435 | break; |
1436 | ||
1437 | default: | |
1438 | return NOTIFY_DONE; | |
1439 | } | |
1440 | ||
1441 | return NOTIFY_OK; | |
1442 | } | |
1443 | ||
1444 | ||
d7268a31 | 1445 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1446 | { |
6e32d479 FY |
1447 | /* |
1448 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1449 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1450 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1451 | */ | |
79cfbdfa SB |
1452 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1453 | return 0; | |
1454 | } | |
1455 | core_initcall(cpu_hotplug_pm_sync_init); | |
1456 | ||
f3de4be9 | 1457 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1458 | |
8ce371f9 PZ |
1459 | int __boot_cpu_id; |
1460 | ||
68f4f1ec | 1461 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1462 | |
cff7d378 | 1463 | /* Boot processor state steps */ |
17a2f1ce | 1464 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1465 | [CPUHP_OFFLINE] = { |
1466 | .name = "offline", | |
3c1627e9 TG |
1467 | .startup.single = NULL, |
1468 | .teardown.single = NULL, | |
cff7d378 TG |
1469 | }, |
1470 | #ifdef CONFIG_SMP | |
1471 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1472 | .name = "threads:prepare", |
3c1627e9 TG |
1473 | .startup.single = smpboot_create_threads, |
1474 | .teardown.single = NULL, | |
757c989b | 1475 | .cant_stop = true, |
cff7d378 | 1476 | }, |
00e16c3d | 1477 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1478 | .name = "perf:prepare", |
1479 | .startup.single = perf_event_init_cpu, | |
1480 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1481 | }, |
7ee681b2 | 1482 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1483 | .name = "workqueue:prepare", |
1484 | .startup.single = workqueue_prepare_cpu, | |
1485 | .teardown.single = NULL, | |
7ee681b2 | 1486 | }, |
27590dc1 | 1487 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1488 | .name = "hrtimers:prepare", |
1489 | .startup.single = hrtimers_prepare_cpu, | |
1490 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1491 | }, |
31487f83 | 1492 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1493 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1494 | .startup.single = smpcfd_prepare_cpu, |
1495 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1496 | }, |
e6d4989a RW |
1497 | [CPUHP_RELAY_PREPARE] = { |
1498 | .name = "relay:prepare", | |
1499 | .startup.single = relay_prepare_cpu, | |
1500 | .teardown.single = NULL, | |
1501 | }, | |
6731d4f1 SAS |
1502 | [CPUHP_SLAB_PREPARE] = { |
1503 | .name = "slab:prepare", | |
1504 | .startup.single = slab_prepare_cpu, | |
1505 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1506 | }, |
4df83742 | 1507 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1508 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1509 | .startup.single = rcutree_prepare_cpu, |
1510 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1511 | }, |
4fae16df RC |
1512 | /* |
1513 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1514 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1515 | * otherwise a RCU stall occurs. | |
1516 | */ | |
26456f87 | 1517 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1518 | .name = "timers:prepare", |
26456f87 | 1519 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1520 | .teardown.single = timers_dead_cpu, |
4fae16df | 1521 | }, |
d10ef6f9 | 1522 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1523 | [CPUHP_BRINGUP_CPU] = { |
1524 | .name = "cpu:bringup", | |
3c1627e9 TG |
1525 | .startup.single = bringup_cpu, |
1526 | .teardown.single = NULL, | |
757c989b | 1527 | .cant_stop = true, |
4baa0afc | 1528 | }, |
d10ef6f9 TG |
1529 | /* Final state before CPU kills itself */ |
1530 | [CPUHP_AP_IDLE_DEAD] = { | |
1531 | .name = "idle:dead", | |
1532 | }, | |
1533 | /* | |
1534 | * Last state before CPU enters the idle loop to die. Transient state | |
1535 | * for synchronization. | |
1536 | */ | |
1537 | [CPUHP_AP_OFFLINE] = { | |
1538 | .name = "ap:offline", | |
1539 | .cant_stop = true, | |
1540 | }, | |
9cf7243d TG |
1541 | /* First state is scheduler control. Interrupts are disabled */ |
1542 | [CPUHP_AP_SCHED_STARTING] = { | |
1543 | .name = "sched:starting", | |
3c1627e9 TG |
1544 | .startup.single = sched_cpu_starting, |
1545 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1546 | }, |
4df83742 | 1547 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1548 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1549 | .startup.single = NULL, |
1550 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1551 | }, |
46febd37 LJ |
1552 | [CPUHP_AP_SMPCFD_DYING] = { |
1553 | .name = "smpcfd:dying", | |
1554 | .startup.single = NULL, | |
1555 | .teardown.single = smpcfd_dying_cpu, | |
1556 | }, | |
d10ef6f9 TG |
1557 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1558 | * state for synchronsization */ | |
1559 | [CPUHP_AP_ONLINE] = { | |
1560 | .name = "ap:online", | |
1561 | }, | |
17a2f1ce LJ |
1562 | /* |
1563 | * Handled on controll processor until the plugged processor manages | |
1564 | * this itself. | |
1565 | */ | |
1566 | [CPUHP_TEARDOWN_CPU] = { | |
1567 | .name = "cpu:teardown", | |
1568 | .startup.single = NULL, | |
1569 | .teardown.single = takedown_cpu, | |
1570 | .cant_stop = true, | |
1571 | }, | |
d10ef6f9 | 1572 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1573 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1574 | .name = "smpboot/threads:online", |
3c1627e9 | 1575 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1576 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1577 | }, |
c5cb83bb TG |
1578 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1579 | .name = "irq/affinity:online", | |
1580 | .startup.single = irq_affinity_online_cpu, | |
1581 | .teardown.single = NULL, | |
1582 | }, | |
00e16c3d | 1583 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1584 | .name = "perf:online", |
1585 | .startup.single = perf_event_init_cpu, | |
1586 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1587 | }, |
9cf57731 PZ |
1588 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1589 | .name = "lockup_detector:online", | |
1590 | .startup.single = lockup_detector_online_cpu, | |
1591 | .teardown.single = lockup_detector_offline_cpu, | |
1592 | }, | |
7ee681b2 | 1593 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1594 | .name = "workqueue:online", |
1595 | .startup.single = workqueue_online_cpu, | |
1596 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1597 | }, |
4df83742 | 1598 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1599 | .name = "RCU/tree:online", |
3c1627e9 TG |
1600 | .startup.single = rcutree_online_cpu, |
1601 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1602 | }, |
4baa0afc | 1603 | #endif |
d10ef6f9 TG |
1604 | /* |
1605 | * The dynamically registered state space is here | |
1606 | */ | |
1607 | ||
aaddd7d1 TG |
1608 | #ifdef CONFIG_SMP |
1609 | /* Last state is scheduler control setting the cpu active */ | |
1610 | [CPUHP_AP_ACTIVE] = { | |
1611 | .name = "sched:active", | |
3c1627e9 TG |
1612 | .startup.single = sched_cpu_activate, |
1613 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1614 | }, |
1615 | #endif | |
1616 | ||
d10ef6f9 | 1617 | /* CPU is fully up and running. */ |
4baa0afc TG |
1618 | [CPUHP_ONLINE] = { |
1619 | .name = "online", | |
3c1627e9 TG |
1620 | .startup.single = NULL, |
1621 | .teardown.single = NULL, | |
4baa0afc TG |
1622 | }, |
1623 | }; | |
1624 | ||
5b7aa87e TG |
1625 | /* Sanity check for callbacks */ |
1626 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1627 | { | |
1628 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1629 | return -EINVAL; | |
1630 | return 0; | |
1631 | } | |
1632 | ||
dc280d93 TG |
1633 | /* |
1634 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1635 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1636 | * by having no name assigned. | |
1637 | */ | |
1638 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1639 | { | |
4205e478 TG |
1640 | enum cpuhp_state i, end; |
1641 | struct cpuhp_step *step; | |
dc280d93 | 1642 | |
4205e478 TG |
1643 | switch (state) { |
1644 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1645 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1646 | end = CPUHP_AP_ONLINE_DYN_END; |
1647 | break; | |
1648 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1649 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1650 | end = CPUHP_BP_PREPARE_DYN_END; |
1651 | break; | |
1652 | default: | |
1653 | return -EINVAL; | |
1654 | } | |
1655 | ||
1656 | for (i = state; i <= end; i++, step++) { | |
1657 | if (!step->name) | |
dc280d93 TG |
1658 | return i; |
1659 | } | |
1660 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1661 | return -ENOSPC; | |
1662 | } | |
1663 | ||
1664 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1665 | int (*startup)(unsigned int cpu), | |
1666 | int (*teardown)(unsigned int cpu), | |
1667 | bool multi_instance) | |
5b7aa87e TG |
1668 | { |
1669 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1670 | struct cpuhp_step *sp; | |
dc280d93 | 1671 | int ret = 0; |
5b7aa87e | 1672 | |
0c96b273 EB |
1673 | /* |
1674 | * If name is NULL, then the state gets removed. | |
1675 | * | |
1676 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1677 | * the first allocation from these dynamic ranges, so the removal | |
1678 | * would trigger a new allocation and clear the wrong (already | |
1679 | * empty) state, leaving the callbacks of the to be cleared state | |
1680 | * dangling, which causes wreckage on the next hotplug operation. | |
1681 | */ | |
1682 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1683 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1684 | ret = cpuhp_reserve_state(state); |
1685 | if (ret < 0) | |
dc434e05 | 1686 | return ret; |
dc280d93 TG |
1687 | state = ret; |
1688 | } | |
5b7aa87e | 1689 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1690 | if (name && sp->name) |
1691 | return -EBUSY; | |
1692 | ||
3c1627e9 TG |
1693 | sp->startup.single = startup; |
1694 | sp->teardown.single = teardown; | |
5b7aa87e | 1695 | sp->name = name; |
cf392d10 TG |
1696 | sp->multi_instance = multi_instance; |
1697 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1698 | return ret; |
5b7aa87e TG |
1699 | } |
1700 | ||
1701 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1702 | { | |
3c1627e9 | 1703 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1704 | } |
1705 | ||
5b7aa87e TG |
1706 | /* |
1707 | * Call the startup/teardown function for a step either on the AP or | |
1708 | * on the current CPU. | |
1709 | */ | |
cf392d10 TG |
1710 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1711 | struct hlist_node *node) | |
5b7aa87e | 1712 | { |
a724632c | 1713 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1714 | int ret; |
1715 | ||
4dddfb5f PZ |
1716 | /* |
1717 | * If there's nothing to do, we done. | |
1718 | * Relies on the union for multi_instance. | |
1719 | */ | |
3c1627e9 TG |
1720 | if ((bringup && !sp->startup.single) || |
1721 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1722 | return 0; |
5b7aa87e TG |
1723 | /* |
1724 | * The non AP bound callbacks can fail on bringup. On teardown | |
1725 | * e.g. module removal we crash for now. | |
1726 | */ | |
1cf4f629 TG |
1727 | #ifdef CONFIG_SMP |
1728 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1729 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1730 | else |
96abb968 | 1731 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1732 | #else |
96abb968 | 1733 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1734 | #endif |
5b7aa87e TG |
1735 | BUG_ON(ret && !bringup); |
1736 | return ret; | |
1737 | } | |
1738 | ||
1739 | /* | |
1740 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1741 | * | |
1742 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1743 | */ | |
1744 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1745 | struct hlist_node *node) |
5b7aa87e TG |
1746 | { |
1747 | int cpu; | |
1748 | ||
5b7aa87e TG |
1749 | /* Roll back the already executed steps on the other cpus */ |
1750 | for_each_present_cpu(cpu) { | |
1751 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1752 | int cpustate = st->state; | |
1753 | ||
1754 | if (cpu >= failedcpu) | |
1755 | break; | |
1756 | ||
1757 | /* Did we invoke the startup call on that cpu ? */ | |
1758 | if (cpustate >= state) | |
cf392d10 | 1759 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1760 | } |
1761 | } | |
1762 | ||
9805c673 TG |
1763 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1764 | struct hlist_node *node, | |
1765 | bool invoke) | |
cf392d10 TG |
1766 | { |
1767 | struct cpuhp_step *sp; | |
1768 | int cpu; | |
1769 | int ret; | |
1770 | ||
9805c673 TG |
1771 | lockdep_assert_cpus_held(); |
1772 | ||
cf392d10 TG |
1773 | sp = cpuhp_get_step(state); |
1774 | if (sp->multi_instance == false) | |
1775 | return -EINVAL; | |
1776 | ||
dc434e05 | 1777 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1778 | |
3c1627e9 | 1779 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1780 | goto add_node; |
1781 | ||
1782 | /* | |
1783 | * Try to call the startup callback for each present cpu | |
1784 | * depending on the hotplug state of the cpu. | |
1785 | */ | |
1786 | for_each_present_cpu(cpu) { | |
1787 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1788 | int cpustate = st->state; | |
1789 | ||
1790 | if (cpustate < state) | |
1791 | continue; | |
1792 | ||
1793 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1794 | if (ret) { | |
3c1627e9 | 1795 | if (sp->teardown.multi) |
cf392d10 | 1796 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1797 | goto unlock; |
cf392d10 TG |
1798 | } |
1799 | } | |
1800 | add_node: | |
1801 | ret = 0; | |
cf392d10 | 1802 | hlist_add_head(node, &sp->list); |
dc434e05 | 1803 | unlock: |
cf392d10 | 1804 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1805 | return ret; |
1806 | } | |
1807 | ||
1808 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1809 | bool invoke) | |
1810 | { | |
1811 | int ret; | |
1812 | ||
1813 | cpus_read_lock(); | |
1814 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1815 | cpus_read_unlock(); |
cf392d10 TG |
1816 | return ret; |
1817 | } | |
1818 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1819 | ||
5b7aa87e | 1820 | /** |
71def423 | 1821 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1822 | * @state: The state to setup |
1823 | * @invoke: If true, the startup function is invoked for cpus where | |
1824 | * cpu state >= @state | |
1825 | * @startup: startup callback function | |
1826 | * @teardown: teardown callback function | |
1827 | * @multi_instance: State is set up for multiple instances which get | |
1828 | * added afterwards. | |
5b7aa87e | 1829 | * |
71def423 | 1830 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1831 | * Returns: |
1832 | * On success: | |
1833 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1834 | * 0 for all other states | |
1835 | * On failure: proper (negative) error code | |
5b7aa87e | 1836 | */ |
71def423 SAS |
1837 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1838 | const char *name, bool invoke, | |
1839 | int (*startup)(unsigned int cpu), | |
1840 | int (*teardown)(unsigned int cpu), | |
1841 | bool multi_instance) | |
5b7aa87e TG |
1842 | { |
1843 | int cpu, ret = 0; | |
b9d9d691 | 1844 | bool dynstate; |
5b7aa87e | 1845 | |
71def423 SAS |
1846 | lockdep_assert_cpus_held(); |
1847 | ||
5b7aa87e TG |
1848 | if (cpuhp_cb_check(state) || !name) |
1849 | return -EINVAL; | |
1850 | ||
dc434e05 | 1851 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1852 | |
dc280d93 TG |
1853 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1854 | multi_instance); | |
5b7aa87e | 1855 | |
b9d9d691 TG |
1856 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1857 | if (ret > 0 && dynstate) { | |
1858 | state = ret; | |
1859 | ret = 0; | |
1860 | } | |
1861 | ||
dc280d93 | 1862 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1863 | goto out; |
1864 | ||
1865 | /* | |
1866 | * Try to call the startup callback for each present cpu | |
1867 | * depending on the hotplug state of the cpu. | |
1868 | */ | |
1869 | for_each_present_cpu(cpu) { | |
1870 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1871 | int cpustate = st->state; | |
1872 | ||
1873 | if (cpustate < state) | |
1874 | continue; | |
1875 | ||
cf392d10 | 1876 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1877 | if (ret) { |
a724632c | 1878 | if (teardown) |
cf392d10 TG |
1879 | cpuhp_rollback_install(cpu, state, NULL); |
1880 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1881 | goto out; |
1882 | } | |
1883 | } | |
1884 | out: | |
dc434e05 | 1885 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1886 | /* |
1887 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1888 | * dynamically allocated state in case of success. | |
1889 | */ | |
b9d9d691 | 1890 | if (!ret && dynstate) |
5b7aa87e TG |
1891 | return state; |
1892 | return ret; | |
1893 | } | |
71def423 SAS |
1894 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1895 | ||
1896 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1897 | const char *name, bool invoke, | |
1898 | int (*startup)(unsigned int cpu), | |
1899 | int (*teardown)(unsigned int cpu), | |
1900 | bool multi_instance) | |
1901 | { | |
1902 | int ret; | |
1903 | ||
1904 | cpus_read_lock(); | |
1905 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1906 | teardown, multi_instance); | |
1907 | cpus_read_unlock(); | |
1908 | return ret; | |
1909 | } | |
5b7aa87e TG |
1910 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1911 | ||
cf392d10 TG |
1912 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1913 | struct hlist_node *node, bool invoke) | |
1914 | { | |
1915 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1916 | int cpu; | |
1917 | ||
1918 | BUG_ON(cpuhp_cb_check(state)); | |
1919 | ||
1920 | if (!sp->multi_instance) | |
1921 | return -EINVAL; | |
1922 | ||
8f553c49 | 1923 | cpus_read_lock(); |
dc434e05 SAS |
1924 | mutex_lock(&cpuhp_state_mutex); |
1925 | ||
cf392d10 TG |
1926 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1927 | goto remove; | |
1928 | /* | |
1929 | * Call the teardown callback for each present cpu depending | |
1930 | * on the hotplug state of the cpu. This function is not | |
1931 | * allowed to fail currently! | |
1932 | */ | |
1933 | for_each_present_cpu(cpu) { | |
1934 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1935 | int cpustate = st->state; | |
1936 | ||
1937 | if (cpustate >= state) | |
1938 | cpuhp_issue_call(cpu, state, false, node); | |
1939 | } | |
1940 | ||
1941 | remove: | |
cf392d10 TG |
1942 | hlist_del(node); |
1943 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1944 | cpus_read_unlock(); |
cf392d10 TG |
1945 | |
1946 | return 0; | |
1947 | } | |
1948 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1949 | |
5b7aa87e | 1950 | /** |
71def423 | 1951 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1952 | * @state: The state to remove |
1953 | * @invoke: If true, the teardown function is invoked for cpus where | |
1954 | * cpu state >= @state | |
1955 | * | |
71def423 | 1956 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1957 | * The teardown callback is currently not allowed to fail. Think |
1958 | * about module removal! | |
1959 | */ | |
71def423 | 1960 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1961 | { |
cf392d10 | 1962 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1963 | int cpu; |
1964 | ||
1965 | BUG_ON(cpuhp_cb_check(state)); | |
1966 | ||
71def423 | 1967 | lockdep_assert_cpus_held(); |
5b7aa87e | 1968 | |
dc434e05 | 1969 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1970 | if (sp->multi_instance) { |
1971 | WARN(!hlist_empty(&sp->list), | |
1972 | "Error: Removing state %d which has instances left.\n", | |
1973 | state); | |
1974 | goto remove; | |
1975 | } | |
1976 | ||
a724632c | 1977 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1978 | goto remove; |
1979 | ||
1980 | /* | |
1981 | * Call the teardown callback for each present cpu depending | |
1982 | * on the hotplug state of the cpu. This function is not | |
1983 | * allowed to fail currently! | |
1984 | */ | |
1985 | for_each_present_cpu(cpu) { | |
1986 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1987 | int cpustate = st->state; | |
1988 | ||
1989 | if (cpustate >= state) | |
cf392d10 | 1990 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1991 | } |
1992 | remove: | |
cf392d10 | 1993 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1994 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1995 | } |
1996 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1997 | ||
1998 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1999 | { | |
2000 | cpus_read_lock(); | |
2001 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 2002 | cpus_read_unlock(); |
5b7aa87e TG |
2003 | } |
2004 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
2005 | ||
dc8d37ed AB |
2006 | #ifdef CONFIG_HOTPLUG_SMT |
2007 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2008 | { | |
2009 | struct device *dev = get_cpu_device(cpu); | |
2010 | ||
2011 | dev->offline = true; | |
2012 | /* Tell user space about the state change */ | |
2013 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2014 | } | |
2015 | ||
2016 | static void cpuhp_online_cpu_device(unsigned int cpu) | |
2017 | { | |
2018 | struct device *dev = get_cpu_device(cpu); | |
2019 | ||
2020 | dev->offline = false; | |
2021 | /* Tell user space about the state change */ | |
2022 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2023 | } | |
2024 | ||
2025 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) | |
2026 | { | |
2027 | int cpu, ret = 0; | |
2028 | ||
2029 | cpu_maps_update_begin(); | |
2030 | for_each_online_cpu(cpu) { | |
2031 | if (topology_is_primary_thread(cpu)) | |
2032 | continue; | |
2033 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2034 | if (ret) | |
2035 | break; | |
2036 | /* | |
2037 | * As this needs to hold the cpu maps lock it's impossible | |
2038 | * to call device_offline() because that ends up calling | |
2039 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2040 | * needs to be held as this might race against in kernel | |
2041 | * abusers of the hotplug machinery (thermal management). | |
2042 | * | |
2043 | * So nothing would update device:offline state. That would | |
2044 | * leave the sysfs entry stale and prevent onlining after | |
2045 | * smt control has been changed to 'off' again. This is | |
2046 | * called under the sysfs hotplug lock, so it is properly | |
2047 | * serialized against the regular offline usage. | |
2048 | */ | |
2049 | cpuhp_offline_cpu_device(cpu); | |
2050 | } | |
2051 | if (!ret) | |
2052 | cpu_smt_control = ctrlval; | |
2053 | cpu_maps_update_done(); | |
2054 | return ret; | |
2055 | } | |
2056 | ||
2057 | int cpuhp_smt_enable(void) | |
2058 | { | |
2059 | int cpu, ret = 0; | |
2060 | ||
2061 | cpu_maps_update_begin(); | |
2062 | cpu_smt_control = CPU_SMT_ENABLED; | |
2063 | for_each_present_cpu(cpu) { | |
2064 | /* Skip online CPUs and CPUs on offline nodes */ | |
2065 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2066 | continue; | |
2067 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2068 | if (ret) | |
2069 | break; | |
2070 | /* See comment in cpuhp_smt_disable() */ | |
2071 | cpuhp_online_cpu_device(cpu); | |
2072 | } | |
2073 | cpu_maps_update_done(); | |
2074 | return ret; | |
2075 | } | |
2076 | #endif | |
2077 | ||
98f8cdce TG |
2078 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
2079 | static ssize_t show_cpuhp_state(struct device *dev, | |
2080 | struct device_attribute *attr, char *buf) | |
2081 | { | |
2082 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2083 | ||
2084 | return sprintf(buf, "%d\n", st->state); | |
2085 | } | |
2086 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
2087 | ||
757c989b TG |
2088 | static ssize_t write_cpuhp_target(struct device *dev, |
2089 | struct device_attribute *attr, | |
2090 | const char *buf, size_t count) | |
2091 | { | |
2092 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2093 | struct cpuhp_step *sp; | |
2094 | int target, ret; | |
2095 | ||
2096 | ret = kstrtoint(buf, 10, &target); | |
2097 | if (ret) | |
2098 | return ret; | |
2099 | ||
2100 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
2101 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
2102 | return -EINVAL; | |
2103 | #else | |
2104 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
2105 | return -EINVAL; | |
2106 | #endif | |
2107 | ||
2108 | ret = lock_device_hotplug_sysfs(); | |
2109 | if (ret) | |
2110 | return ret; | |
2111 | ||
2112 | mutex_lock(&cpuhp_state_mutex); | |
2113 | sp = cpuhp_get_step(target); | |
2114 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
2115 | mutex_unlock(&cpuhp_state_mutex); | |
2116 | if (ret) | |
40da1b11 | 2117 | goto out; |
757c989b TG |
2118 | |
2119 | if (st->state < target) | |
2120 | ret = do_cpu_up(dev->id, target); | |
2121 | else | |
2122 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 2123 | out: |
757c989b TG |
2124 | unlock_device_hotplug(); |
2125 | return ret ? ret : count; | |
2126 | } | |
2127 | ||
98f8cdce TG |
2128 | static ssize_t show_cpuhp_target(struct device *dev, |
2129 | struct device_attribute *attr, char *buf) | |
2130 | { | |
2131 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2132 | ||
2133 | return sprintf(buf, "%d\n", st->target); | |
2134 | } | |
757c989b | 2135 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 2136 | |
1db49484 PZ |
2137 | |
2138 | static ssize_t write_cpuhp_fail(struct device *dev, | |
2139 | struct device_attribute *attr, | |
2140 | const char *buf, size_t count) | |
2141 | { | |
2142 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2143 | struct cpuhp_step *sp; | |
2144 | int fail, ret; | |
2145 | ||
2146 | ret = kstrtoint(buf, 10, &fail); | |
2147 | if (ret) | |
2148 | return ret; | |
2149 | ||
33d4a5a7 ET |
2150 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
2151 | return -EINVAL; | |
2152 | ||
1db49484 PZ |
2153 | /* |
2154 | * Cannot fail STARTING/DYING callbacks. | |
2155 | */ | |
2156 | if (cpuhp_is_atomic_state(fail)) | |
2157 | return -EINVAL; | |
2158 | ||
2159 | /* | |
2160 | * Cannot fail anything that doesn't have callbacks. | |
2161 | */ | |
2162 | mutex_lock(&cpuhp_state_mutex); | |
2163 | sp = cpuhp_get_step(fail); | |
2164 | if (!sp->startup.single && !sp->teardown.single) | |
2165 | ret = -EINVAL; | |
2166 | mutex_unlock(&cpuhp_state_mutex); | |
2167 | if (ret) | |
2168 | return ret; | |
2169 | ||
2170 | st->fail = fail; | |
2171 | ||
2172 | return count; | |
2173 | } | |
2174 | ||
2175 | static ssize_t show_cpuhp_fail(struct device *dev, | |
2176 | struct device_attribute *attr, char *buf) | |
2177 | { | |
2178 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2179 | ||
2180 | return sprintf(buf, "%d\n", st->fail); | |
2181 | } | |
2182 | ||
2183 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
2184 | ||
98f8cdce TG |
2185 | static struct attribute *cpuhp_cpu_attrs[] = { |
2186 | &dev_attr_state.attr, | |
2187 | &dev_attr_target.attr, | |
1db49484 | 2188 | &dev_attr_fail.attr, |
98f8cdce TG |
2189 | NULL |
2190 | }; | |
2191 | ||
993647a2 | 2192 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2193 | .attrs = cpuhp_cpu_attrs, |
2194 | .name = "hotplug", | |
2195 | NULL | |
2196 | }; | |
2197 | ||
2198 | static ssize_t show_cpuhp_states(struct device *dev, | |
2199 | struct device_attribute *attr, char *buf) | |
2200 | { | |
2201 | ssize_t cur, res = 0; | |
2202 | int i; | |
2203 | ||
2204 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2205 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2206 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2207 | ||
2208 | if (sp->name) { | |
2209 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2210 | buf += cur; | |
2211 | res += cur; | |
2212 | } | |
2213 | } | |
2214 | mutex_unlock(&cpuhp_state_mutex); | |
2215 | return res; | |
2216 | } | |
2217 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2218 | ||
2219 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2220 | &dev_attr_states.attr, | |
2221 | NULL | |
2222 | }; | |
2223 | ||
993647a2 | 2224 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2225 | .attrs = cpuhp_cpu_root_attrs, |
2226 | .name = "hotplug", | |
2227 | NULL | |
2228 | }; | |
2229 | ||
05736e4a TG |
2230 | #ifdef CONFIG_HOTPLUG_SMT |
2231 | ||
05736e4a | 2232 | static ssize_t |
de7b77e5 JP |
2233 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2234 | const char *buf, size_t count) | |
05736e4a TG |
2235 | { |
2236 | int ctrlval, ret; | |
2237 | ||
2238 | if (sysfs_streq(buf, "on")) | |
2239 | ctrlval = CPU_SMT_ENABLED; | |
2240 | else if (sysfs_streq(buf, "off")) | |
2241 | ctrlval = CPU_SMT_DISABLED; | |
2242 | else if (sysfs_streq(buf, "forceoff")) | |
2243 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2244 | else | |
2245 | return -EINVAL; | |
2246 | ||
2247 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2248 | return -EPERM; | |
2249 | ||
2250 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2251 | return -ENODEV; | |
2252 | ||
2253 | ret = lock_device_hotplug_sysfs(); | |
2254 | if (ret) | |
2255 | return ret; | |
2256 | ||
2257 | if (ctrlval != cpu_smt_control) { | |
2258 | switch (ctrlval) { | |
2259 | case CPU_SMT_ENABLED: | |
215af549 | 2260 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2261 | break; |
2262 | case CPU_SMT_DISABLED: | |
2263 | case CPU_SMT_FORCE_DISABLED: | |
2264 | ret = cpuhp_smt_disable(ctrlval); | |
2265 | break; | |
2266 | } | |
2267 | } | |
2268 | ||
2269 | unlock_device_hotplug(); | |
2270 | return ret ? ret : count; | |
2271 | } | |
de7b77e5 JP |
2272 | |
2273 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2274 | static ssize_t | |
2275 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2276 | const char *buf, size_t count) | |
2277 | { | |
2278 | return -ENODEV; | |
2279 | } | |
2280 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2281 | ||
2282 | static const char *smt_states[] = { | |
2283 | [CPU_SMT_ENABLED] = "on", | |
2284 | [CPU_SMT_DISABLED] = "off", | |
2285 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2286 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2287 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2288 | }; | |
2289 | ||
2290 | static ssize_t | |
2291 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2292 | { | |
2293 | const char *state = smt_states[cpu_smt_control]; | |
2294 | ||
2295 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2296 | } | |
2297 | ||
2298 | static ssize_t | |
2299 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2300 | const char *buf, size_t count) | |
2301 | { | |
2302 | return __store_smt_control(dev, attr, buf, count); | |
2303 | } | |
05736e4a TG |
2304 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
2305 | ||
2306 | static ssize_t | |
2307 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2308 | { | |
de7b77e5 | 2309 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a TG |
2310 | } |
2311 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2312 | ||
2313 | static struct attribute *cpuhp_smt_attrs[] = { | |
2314 | &dev_attr_control.attr, | |
2315 | &dev_attr_active.attr, | |
2316 | NULL | |
2317 | }; | |
2318 | ||
2319 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2320 | .attrs = cpuhp_smt_attrs, | |
2321 | .name = "smt", | |
2322 | NULL | |
2323 | }; | |
2324 | ||
de7b77e5 | 2325 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2326 | { |
05736e4a TG |
2327 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2328 | &cpuhp_smt_attr_group); | |
2329 | } | |
2330 | ||
98f8cdce TG |
2331 | static int __init cpuhp_sysfs_init(void) |
2332 | { | |
2333 | int cpu, ret; | |
2334 | ||
de7b77e5 | 2335 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2336 | if (ret) |
2337 | return ret; | |
2338 | ||
98f8cdce TG |
2339 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2340 | &cpuhp_cpu_root_attr_group); | |
2341 | if (ret) | |
2342 | return ret; | |
2343 | ||
2344 | for_each_possible_cpu(cpu) { | |
2345 | struct device *dev = get_cpu_device(cpu); | |
2346 | ||
2347 | if (!dev) | |
2348 | continue; | |
2349 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2350 | if (ret) | |
2351 | return ret; | |
2352 | } | |
2353 | return 0; | |
2354 | } | |
2355 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2356 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2357 | |
e56b3bc7 LT |
2358 | /* |
2359 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2360 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2361 | * | |
e0b582ec | 2362 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2363 | * mask value that has a single bit set only. |
2364 | */ | |
b8d317d1 | 2365 | |
e56b3bc7 | 2366 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2367 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2368 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2369 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2370 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2371 | |
e56b3bc7 LT |
2372 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2373 | ||
2374 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2375 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2376 | #if BITS_PER_LONG > 32 | |
2377 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2378 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2379 | #endif |
2380 | }; | |
e56b3bc7 | 2381 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2382 | |
2383 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2384 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2385 | |
2386 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2387 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2388 | = {CPU_BITS_ALL}; |
b3199c02 | 2389 | #else |
4b804c85 | 2390 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2391 | #endif |
4b804c85 | 2392 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2393 | |
4b804c85 RV |
2394 | struct cpumask __cpu_online_mask __read_mostly; |
2395 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2396 | |
4b804c85 RV |
2397 | struct cpumask __cpu_present_mask __read_mostly; |
2398 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2399 | |
4b804c85 RV |
2400 | struct cpumask __cpu_active_mask __read_mostly; |
2401 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2402 | |
0c09ab96 TG |
2403 | atomic_t __num_online_cpus __read_mostly; |
2404 | EXPORT_SYMBOL(__num_online_cpus); | |
2405 | ||
3fa41520 RR |
2406 | void init_cpu_present(const struct cpumask *src) |
2407 | { | |
c4c54dd1 | 2408 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2409 | } |
2410 | ||
2411 | void init_cpu_possible(const struct cpumask *src) | |
2412 | { | |
c4c54dd1 | 2413 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2414 | } |
2415 | ||
2416 | void init_cpu_online(const struct cpumask *src) | |
2417 | { | |
c4c54dd1 | 2418 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2419 | } |
cff7d378 | 2420 | |
0c09ab96 TG |
2421 | void set_cpu_online(unsigned int cpu, bool online) |
2422 | { | |
2423 | /* | |
2424 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2425 | * function by the reboot and kexec code which invoke it from | |
2426 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2427 | * regular CPU hotplug is properly serialized. | |
2428 | * | |
2429 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2430 | * does not protect readers which are not serialized against | |
2431 | * concurrent hotplug operations. | |
2432 | */ | |
2433 | if (online) { | |
2434 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2435 | atomic_inc(&__num_online_cpus); | |
2436 | } else { | |
2437 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2438 | atomic_dec(&__num_online_cpus); | |
2439 | } | |
2440 | } | |
2441 | ||
cff7d378 TG |
2442 | /* |
2443 | * Activate the first processor. | |
2444 | */ | |
2445 | void __init boot_cpu_init(void) | |
2446 | { | |
2447 | int cpu = smp_processor_id(); | |
2448 | ||
2449 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2450 | set_cpu_online(cpu, true); | |
2451 | set_cpu_active(cpu, true); | |
2452 | set_cpu_present(cpu, true); | |
2453 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2454 | |
2455 | #ifdef CONFIG_SMP | |
2456 | __boot_cpu_id = cpu; | |
2457 | #endif | |
cff7d378 TG |
2458 | } |
2459 | ||
2460 | /* | |
2461 | * Must be called _AFTER_ setting up the per_cpu areas | |
2462 | */ | |
b5b1404d | 2463 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2464 | { |
269777aa | 2465 | #ifdef CONFIG_SMP |
e797bda3 | 2466 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2467 | #endif |
0cc3cd21 | 2468 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2469 | } |
98af8452 | 2470 | |
731dc9df TH |
2471 | /* |
2472 | * These are used for a global "mitigations=" cmdline option for toggling | |
2473 | * optional CPU mitigations. | |
2474 | */ | |
2475 | enum cpu_mitigations { | |
2476 | CPU_MITIGATIONS_OFF, | |
2477 | CPU_MITIGATIONS_AUTO, | |
2478 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2479 | }; | |
2480 | ||
2481 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2482 | CPU_MITIGATIONS_AUTO; | |
98af8452 JP |
2483 | |
2484 | static int __init mitigations_parse_cmdline(char *arg) | |
2485 | { | |
2486 | if (!strcmp(arg, "off")) | |
2487 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2488 | else if (!strcmp(arg, "auto")) | |
2489 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2490 | else if (!strcmp(arg, "auto,nosmt")) | |
2491 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2492 | else |
2493 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2494 | arg); | |
98af8452 JP |
2495 | |
2496 | return 0; | |
2497 | } | |
2498 | early_param("mitigations", mitigations_parse_cmdline); | |
731dc9df TH |
2499 | |
2500 | /* mitigations=off */ | |
2501 | bool cpu_mitigations_off(void) | |
2502 | { | |
2503 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2504 | } | |
2505 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2506 | ||
2507 | /* mitigations=auto,nosmt */ | |
2508 | bool cpu_mitigations_auto_nosmt(void) | |
2509 | { | |
2510 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2511 | } | |
2512 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |