]>
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> |
29930025 | 12 | #include <linux/sched/task.h> |
fc8944e3 | 13 | #include <linux/sched/smt.h> |
1da177e4 LT |
14 | #include <linux/unistd.h> |
15 | #include <linux/cpu.h> | |
cb79295e AV |
16 | #include <linux/oom.h> |
17 | #include <linux/rcupdate.h> | |
9984de1a | 18 | #include <linux/export.h> |
e4cc2f87 | 19 | #include <linux/bug.h> |
1da177e4 LT |
20 | #include <linux/kthread.h> |
21 | #include <linux/stop_machine.h> | |
81615b62 | 22 | #include <linux/mutex.h> |
5a0e3ad6 | 23 | #include <linux/gfp.h> |
79cfbdfa | 24 | #include <linux/suspend.h> |
a19423b9 | 25 | #include <linux/lockdep.h> |
345527b1 | 26 | #include <linux/tick.h> |
a8994181 | 27 | #include <linux/irq.h> |
941154bd | 28 | #include <linux/nmi.h> |
4cb28ced | 29 | #include <linux/smpboot.h> |
e6d4989a | 30 | #include <linux/relay.h> |
6731d4f1 | 31 | #include <linux/slab.h> |
fc8dffd3 | 32 | #include <linux/percpu-rwsem.h> |
cff7d378 | 33 | |
bb3632c6 | 34 | #include <trace/events/power.h> |
cff7d378 TG |
35 | #define CREATE_TRACE_POINTS |
36 | #include <trace/events/cpuhp.h> | |
1da177e4 | 37 | |
38498a67 TG |
38 | #include "smpboot.h" |
39 | ||
cff7d378 TG |
40 | /** |
41 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
42 | * @state: The current cpu state | |
43 | * @target: The target state | |
4cb28ced TG |
44 | * @thread: Pointer to the hotplug thread |
45 | * @should_run: Thread should execute | |
3b9d6da6 | 46 | * @rollback: Perform a rollback |
a724632c TG |
47 | * @single: Single callback invocation |
48 | * @bringup: Single callback bringup or teardown selector | |
49 | * @cb_state: The state for a single callback (install/uninstall) | |
4cb28ced | 50 | * @result: Result of the operation |
5ebe7742 PZ |
51 | * @done_up: Signal completion to the issuer of the task for cpu-up |
52 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
53 | */ |
54 | struct cpuhp_cpu_state { | |
55 | enum cpuhp_state state; | |
56 | enum cpuhp_state target; | |
1db49484 | 57 | enum cpuhp_state fail; |
4cb28ced TG |
58 | #ifdef CONFIG_SMP |
59 | struct task_struct *thread; | |
60 | bool should_run; | |
3b9d6da6 | 61 | bool rollback; |
a724632c TG |
62 | bool single; |
63 | bool bringup; | |
3762ba90 | 64 | bool booted_once; |
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 | |
49dfe2a6 | 78 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
79 | static struct lockdep_map cpuhp_state_up_map = |
80 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
81 | static struct lockdep_map cpuhp_state_down_map = | |
82 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
83 | ||
84 | ||
76dc6c09 | 85 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
86 | { |
87 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
88 | } | |
89 | ||
76dc6c09 | 90 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
91 | { |
92 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
93 | } | |
94 | #else | |
95 | ||
76dc6c09 MM |
96 | static inline void cpuhp_lock_acquire(bool bringup) { } |
97 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 98 | |
49dfe2a6 TG |
99 | #endif |
100 | ||
cff7d378 TG |
101 | /** |
102 | * cpuhp_step - Hotplug state machine step | |
103 | * @name: Name of the step | |
104 | * @startup: Startup function of the step | |
105 | * @teardown: Teardown function of the step | |
106 | * @skip_onerr: Do not invoke the functions on error rollback | |
107 | * Will go away once the notifiers are gone | |
757c989b | 108 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
109 | */ |
110 | struct cpuhp_step { | |
cf392d10 TG |
111 | const char *name; |
112 | union { | |
3c1627e9 TG |
113 | int (*single)(unsigned int cpu); |
114 | int (*multi)(unsigned int cpu, | |
115 | struct hlist_node *node); | |
116 | } startup; | |
cf392d10 | 117 | union { |
3c1627e9 TG |
118 | int (*single)(unsigned int cpu); |
119 | int (*multi)(unsigned int cpu, | |
120 | struct hlist_node *node); | |
121 | } teardown; | |
cf392d10 TG |
122 | struct hlist_head list; |
123 | bool skip_onerr; | |
124 | bool cant_stop; | |
125 | bool multi_instance; | |
cff7d378 TG |
126 | }; |
127 | ||
98f8cdce | 128 | static DEFINE_MUTEX(cpuhp_state_mutex); |
cff7d378 | 129 | static struct cpuhp_step cpuhp_bp_states[]; |
4baa0afc | 130 | static struct cpuhp_step cpuhp_ap_states[]; |
cff7d378 | 131 | |
a724632c TG |
132 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
133 | { | |
134 | /* | |
135 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
136 | * purposes as that state is handled explicitly in cpu_down. | |
137 | */ | |
138 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
139 | } | |
140 | ||
141 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) | |
142 | { | |
143 | struct cpuhp_step *sp; | |
144 | ||
145 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; | |
146 | return sp + state; | |
147 | } | |
148 | ||
cff7d378 TG |
149 | /** |
150 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
151 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 152 | * @state: The state to do callbacks for |
a724632c | 153 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
154 | * @node: For multi-instance, do a single entry callback for install/remove |
155 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 156 | * |
cf392d10 | 157 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 158 | */ |
a724632c | 159 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
160 | bool bringup, struct hlist_node *node, |
161 | struct hlist_node **lastp) | |
cff7d378 TG |
162 | { |
163 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 164 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
165 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
166 | int (*cb)(unsigned int cpu); | |
167 | int ret, cnt; | |
168 | ||
1db49484 PZ |
169 | if (st->fail == state) { |
170 | st->fail = CPUHP_INVALID; | |
171 | ||
172 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
173 | return 0; | |
174 | ||
175 | return -EAGAIN; | |
176 | } | |
177 | ||
cf392d10 | 178 | if (!step->multi_instance) { |
96abb968 | 179 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 180 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
181 | if (!cb) |
182 | return 0; | |
a724632c | 183 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 184 | ret = cb(cpu); |
a724632c | 185 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
186 | return ret; |
187 | } | |
3c1627e9 | 188 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
189 | if (!cbm) |
190 | return 0; | |
191 | ||
192 | /* Single invocation for instance add/remove */ | |
193 | if (node) { | |
96abb968 | 194 | WARN_ON_ONCE(lastp && *lastp); |
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); | |
198 | return ret; | |
199 | } | |
200 | ||
201 | /* State transition. Invoke on all instances */ | |
202 | cnt = 0; | |
203 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
204 | if (lastp && node == *lastp) |
205 | break; | |
206 | ||
cf392d10 TG |
207 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
208 | ret = cbm(cpu, node); | |
209 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
210 | if (ret) { |
211 | if (!lastp) | |
212 | goto err; | |
213 | ||
214 | *lastp = node; | |
215 | return ret; | |
216 | } | |
cf392d10 TG |
217 | cnt++; |
218 | } | |
96abb968 PZ |
219 | if (lastp) |
220 | *lastp = NULL; | |
cf392d10 TG |
221 | return 0; |
222 | err: | |
223 | /* Rollback the instances if one failed */ | |
3c1627e9 | 224 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
225 | if (!cbm) |
226 | return ret; | |
227 | ||
228 | hlist_for_each(node, &step->list) { | |
229 | if (!cnt--) | |
230 | break; | |
724a8688 PZ |
231 | |
232 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
233 | ret = cbm(cpu, node); | |
234 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
235 | /* | |
236 | * Rollback must not fail, | |
237 | */ | |
238 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
239 | } |
240 | return ret; | |
241 | } | |
242 | ||
98a79d6a | 243 | #ifdef CONFIG_SMP |
5ebe7742 PZ |
244 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
245 | { | |
246 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
247 | wait_for_completion(done); | |
248 | } | |
249 | ||
250 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
251 | { | |
252 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
253 | complete(done); | |
254 | } | |
255 | ||
256 | /* | |
257 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
258 | */ | |
259 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
260 | { | |
261 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
262 | } | |
263 | ||
b3199c02 | 264 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 265 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
266 | bool cpuhp_tasks_frozen; |
267 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 268 | |
79a6cdeb | 269 | /* |
93ae4f97 SB |
270 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
271 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
272 | */ |
273 | void cpu_maps_update_begin(void) | |
274 | { | |
275 | mutex_lock(&cpu_add_remove_lock); | |
276 | } | |
277 | ||
278 | void cpu_maps_update_done(void) | |
279 | { | |
280 | mutex_unlock(&cpu_add_remove_lock); | |
281 | } | |
1da177e4 | 282 | |
fc8dffd3 TG |
283 | /* |
284 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
285 | * Should always be manipulated under cpu_add_remove_lock |
286 | */ | |
287 | static int cpu_hotplug_disabled; | |
288 | ||
79a6cdeb LJ |
289 | #ifdef CONFIG_HOTPLUG_CPU |
290 | ||
fc8dffd3 | 291 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 292 | |
8f553c49 | 293 | void cpus_read_lock(void) |
a9d9baa1 | 294 | { |
fc8dffd3 | 295 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 296 | } |
8f553c49 | 297 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 298 | |
8f553c49 | 299 | void cpus_read_unlock(void) |
a9d9baa1 | 300 | { |
fc8dffd3 | 301 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 302 | } |
8f553c49 | 303 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 304 | |
8f553c49 | 305 | void cpus_write_lock(void) |
d221938c | 306 | { |
fc8dffd3 | 307 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 308 | } |
87af9e7f | 309 | |
8f553c49 | 310 | void cpus_write_unlock(void) |
d221938c | 311 | { |
fc8dffd3 | 312 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
313 | } |
314 | ||
fc8dffd3 | 315 | void lockdep_assert_cpus_held(void) |
d221938c | 316 | { |
8d284339 VS |
317 | /* |
318 | * We can't have hotplug operations before userspace starts running, | |
319 | * and some init codepaths will knowingly not take the hotplug lock. | |
320 | * This is all valid, so mute lockdep until it makes sense to report | |
321 | * unheld locks. | |
322 | */ | |
323 | if (system_state < SYSTEM_RUNNING) | |
324 | return; | |
325 | ||
fc8dffd3 | 326 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 327 | } |
79a6cdeb | 328 | |
16e53dbf SB |
329 | /* |
330 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
331 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
332 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
333 | * hotplug path before performing hotplug operations. So acquiring that lock | |
334 | * guarantees mutual exclusion from any currently running hotplug operations. | |
335 | */ | |
336 | void cpu_hotplug_disable(void) | |
337 | { | |
338 | cpu_maps_update_begin(); | |
89af7ba5 | 339 | cpu_hotplug_disabled++; |
16e53dbf SB |
340 | cpu_maps_update_done(); |
341 | } | |
32145c46 | 342 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 343 | |
01b41159 LW |
344 | static void __cpu_hotplug_enable(void) |
345 | { | |
346 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
347 | return; | |
348 | cpu_hotplug_disabled--; | |
349 | } | |
350 | ||
16e53dbf SB |
351 | void cpu_hotplug_enable(void) |
352 | { | |
353 | cpu_maps_update_begin(); | |
01b41159 | 354 | __cpu_hotplug_enable(); |
16e53dbf SB |
355 | cpu_maps_update_done(); |
356 | } | |
32145c46 | 357 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
b9d10be7 | 358 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 359 | |
fc8944e3 TG |
360 | /* |
361 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
362 | * should override this. | |
363 | */ | |
364 | void __weak arch_smt_update(void) { } | |
365 | ||
3762ba90 TG |
366 | #ifdef CONFIG_HOTPLUG_SMT |
367 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
ade31b9e | 368 | |
44219799 | 369 | void __init cpu_smt_disable(bool force) |
3762ba90 | 370 | { |
44219799 JK |
371 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || |
372 | cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
373 | return; | |
374 | ||
375 | if (force) { | |
3762ba90 TG |
376 | pr_info("SMT: Force disabled\n"); |
377 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
44219799 | 378 | } else { |
e1c18798 | 379 | pr_info("SMT: disabled\n"); |
44219799 | 380 | cpu_smt_control = CPU_SMT_DISABLED; |
3762ba90 | 381 | } |
44219799 JK |
382 | } |
383 | ||
483ec3c6 TG |
384 | /* |
385 | * The decision whether SMT is supported can only be done after the full | |
67cd6fac | 386 | * CPU identification. Called from architecture code. |
ade31b9e TG |
387 | */ |
388 | void __init cpu_smt_check_topology(void) | |
389 | { | |
67cd6fac | 390 | if (!topology_smt_supported()) |
ade31b9e TG |
391 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
392 | } | |
393 | ||
44219799 JK |
394 | static int __init smt_cmdline_disable(char *str) |
395 | { | |
396 | cpu_smt_disable(str && !strcmp(str, "force")); | |
3762ba90 TG |
397 | return 0; |
398 | } | |
399 | early_param("nosmt", smt_cmdline_disable); | |
400 | ||
401 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
402 | { | |
67cd6fac | 403 | if (cpu_smt_control == CPU_SMT_ENABLED) |
3762ba90 TG |
404 | return true; |
405 | ||
67cd6fac | 406 | if (topology_is_primary_thread(cpu)) |
3762ba90 TG |
407 | return true; |
408 | ||
409 | /* | |
410 | * On x86 it's required to boot all logical CPUs at least once so | |
411 | * that the init code can get a chance to set CR4.MCE on each | |
412 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any | |
413 | * core will shutdown the machine. | |
414 | */ | |
415 | return !per_cpu(cpuhp_state, cpu).booted_once; | |
416 | } | |
417 | #else | |
418 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
419 | #endif | |
420 | ||
4dddfb5f PZ |
421 | static inline enum cpuhp_state |
422 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
423 | { | |
424 | enum cpuhp_state prev_state = st->state; | |
425 | ||
426 | st->rollback = false; | |
427 | st->last = NULL; | |
428 | ||
429 | st->target = target; | |
430 | st->single = false; | |
431 | st->bringup = st->state < target; | |
432 | ||
433 | return prev_state; | |
434 | } | |
435 | ||
436 | static inline void | |
437 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
438 | { | |
439 | st->rollback = true; | |
440 | ||
441 | /* | |
442 | * If we have st->last we need to undo partial multi_instance of this | |
443 | * state first. Otherwise start undo at the previous state. | |
444 | */ | |
445 | if (!st->last) { | |
446 | if (st->bringup) | |
447 | st->state--; | |
448 | else | |
449 | st->state++; | |
450 | } | |
451 | ||
452 | st->target = prev_state; | |
453 | st->bringup = !st->bringup; | |
454 | } | |
455 | ||
456 | /* Regular hotplug invocation of the AP hotplug thread */ | |
457 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
458 | { | |
459 | if (!st->single && st->state == st->target) | |
460 | return; | |
461 | ||
462 | st->result = 0; | |
463 | /* | |
464 | * Make sure the above stores are visible before should_run becomes | |
465 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
466 | */ | |
467 | smp_mb(); | |
468 | st->should_run = true; | |
469 | wake_up_process(st->thread); | |
5ebe7742 | 470 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
471 | } |
472 | ||
473 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
474 | { | |
475 | enum cpuhp_state prev_state; | |
476 | int ret; | |
477 | ||
478 | prev_state = cpuhp_set_state(st, target); | |
479 | __cpuhp_kick_ap(st); | |
480 | if ((ret = st->result)) { | |
481 | cpuhp_reset_state(st, prev_state); | |
482 | __cpuhp_kick_ap(st); | |
483 | } | |
484 | ||
485 | return ret; | |
486 | } | |
9cd4f1a4 | 487 | |
8df3e07e TG |
488 | static int bringup_wait_for_ap(unsigned int cpu) |
489 | { | |
490 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
491 | ||
9cd4f1a4 | 492 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 493 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
494 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
495 | return -ECANCELED; | |
9cd4f1a4 TG |
496 | |
497 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ | |
498 | stop_machine_unpark(cpu); | |
499 | kthread_unpark(st->thread); | |
500 | ||
3762ba90 TG |
501 | /* |
502 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
503 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
504 | * CPU marked itself as booted_once in cpu_notify_starting() so the | |
505 | * cpu_smt_allowed() check will now return false if this is not the | |
506 | * primary sibling. | |
507 | */ | |
508 | if (!cpu_smt_allowed(cpu)) | |
509 | return -ECANCELED; | |
510 | ||
4dddfb5f PZ |
511 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
512 | return 0; | |
513 | ||
514 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
515 | } |
516 | ||
ba997462 TG |
517 | static int bringup_cpu(unsigned int cpu) |
518 | { | |
519 | struct task_struct *idle = idle_thread_get(cpu); | |
520 | int ret; | |
521 | ||
aa877175 BO |
522 | /* |
523 | * Some architectures have to walk the irq descriptors to | |
524 | * setup the vector space for the cpu which comes online. | |
525 | * Prevent irq alloc/free across the bringup. | |
526 | */ | |
527 | irq_lock_sparse(); | |
528 | ||
ba997462 TG |
529 | /* Arch-specific enabling code. */ |
530 | ret = __cpu_up(cpu, idle); | |
aa877175 | 531 | irq_unlock_sparse(); |
530e9b76 | 532 | if (ret) |
ba997462 | 533 | return ret; |
9cd4f1a4 | 534 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
535 | } |
536 | ||
2e1a3483 TG |
537 | /* |
538 | * Hotplug state machine related functions | |
539 | */ | |
2e1a3483 | 540 | |
a724632c | 541 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 TG |
542 | { |
543 | for (st->state--; st->state > st->target; st->state--) { | |
a724632c | 544 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
2e1a3483 TG |
545 | |
546 | if (!step->skip_onerr) | |
96abb968 | 547 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); |
2e1a3483 TG |
548 | } |
549 | } | |
550 | ||
5e9247c2 TG |
551 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
552 | { | |
553 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
554 | return true; | |
555 | /* | |
556 | * When CPU hotplug is disabled, then taking the CPU down is not | |
557 | * possible because takedown_cpu() and the architecture and | |
558 | * subsystem specific mechanisms are not available. So the CPU | |
559 | * which would be completely unplugged again needs to stay around | |
560 | * in the current state. | |
561 | */ | |
562 | return st->state <= CPUHP_BRINGUP_CPU; | |
563 | } | |
564 | ||
2e1a3483 | 565 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 566 | enum cpuhp_state target) |
2e1a3483 TG |
567 | { |
568 | enum cpuhp_state prev_state = st->state; | |
569 | int ret = 0; | |
570 | ||
571 | while (st->state < target) { | |
2e1a3483 | 572 | st->state++; |
96abb968 | 573 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 | 574 | if (ret) { |
5e9247c2 TG |
575 | if (can_rollback_cpu(st)) { |
576 | st->target = prev_state; | |
577 | undo_cpu_up(cpu, st); | |
578 | } | |
2e1a3483 TG |
579 | break; |
580 | } | |
581 | } | |
582 | return ret; | |
583 | } | |
584 | ||
4cb28ced TG |
585 | /* |
586 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
587 | */ | |
588 | static void cpuhp_create(unsigned int cpu) | |
589 | { | |
590 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
591 | ||
5ebe7742 PZ |
592 | init_completion(&st->done_up); |
593 | init_completion(&st->done_down); | |
4cb28ced TG |
594 | } |
595 | ||
596 | static int cpuhp_should_run(unsigned int cpu) | |
597 | { | |
598 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
599 | ||
600 | return st->should_run; | |
601 | } | |
602 | ||
4cb28ced TG |
603 | /* |
604 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
605 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
606 | * |
607 | * Each invocation of this function by the smpboot thread does a single AP | |
608 | * state callback. | |
609 | * | |
610 | * It has 3 modes of operation: | |
611 | * - single: runs st->cb_state | |
612 | * - up: runs ++st->state, while st->state < st->target | |
613 | * - down: runs st->state--, while st->state > st->target | |
614 | * | |
615 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
616 | */ |
617 | static void cpuhp_thread_fun(unsigned int cpu) | |
618 | { | |
619 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
620 | bool bringup = st->bringup; |
621 | enum cpuhp_state state; | |
4cb28ced | 622 | |
027c9910 NU |
623 | if (WARN_ON_ONCE(!st->should_run)) |
624 | return; | |
625 | ||
4cb28ced | 626 | /* |
4dddfb5f PZ |
627 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
628 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
629 | */ |
630 | smp_mb(); | |
4cb28ced | 631 | |
5f4b55e1 | 632 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 633 | |
a724632c | 634 | if (st->single) { |
4dddfb5f PZ |
635 | state = st->cb_state; |
636 | st->should_run = false; | |
637 | } else { | |
638 | if (bringup) { | |
639 | st->state++; | |
640 | state = st->state; | |
641 | st->should_run = (st->state < st->target); | |
642 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 643 | } else { |
4dddfb5f PZ |
644 | state = st->state; |
645 | st->state--; | |
646 | st->should_run = (st->state > st->target); | |
647 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 648 | } |
4dddfb5f PZ |
649 | } |
650 | ||
651 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
652 | ||
653 | if (st->rollback) { | |
654 | struct cpuhp_step *step = cpuhp_get_step(state); | |
655 | if (step->skip_onerr) | |
656 | goto next; | |
657 | } | |
658 | ||
659 | if (cpuhp_is_atomic_state(state)) { | |
660 | local_irq_disable(); | |
661 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
662 | local_irq_enable(); | |
3b9d6da6 | 663 | |
4dddfb5f PZ |
664 | /* |
665 | * STARTING/DYING must not fail! | |
666 | */ | |
667 | WARN_ON_ONCE(st->result); | |
4cb28ced | 668 | } else { |
4dddfb5f PZ |
669 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
670 | } | |
671 | ||
672 | if (st->result) { | |
673 | /* | |
674 | * If we fail on a rollback, we're up a creek without no | |
675 | * paddle, no way forward, no way back. We loose, thanks for | |
676 | * playing. | |
677 | */ | |
678 | WARN_ON_ONCE(st->rollback); | |
679 | st->should_run = false; | |
4cb28ced | 680 | } |
4dddfb5f PZ |
681 | |
682 | next: | |
5f4b55e1 | 683 | cpuhp_lock_release(bringup); |
4dddfb5f PZ |
684 | |
685 | if (!st->should_run) | |
5ebe7742 | 686 | complete_ap_thread(st, bringup); |
4cb28ced TG |
687 | } |
688 | ||
689 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 690 | static int |
cf392d10 TG |
691 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
692 | struct hlist_node *node) | |
4cb28ced TG |
693 | { |
694 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 695 | int ret; |
4cb28ced TG |
696 | |
697 | if (!cpu_online(cpu)) | |
698 | return 0; | |
699 | ||
5f4b55e1 PZ |
700 | cpuhp_lock_acquire(false); |
701 | cpuhp_lock_release(false); | |
702 | ||
703 | cpuhp_lock_acquire(true); | |
704 | cpuhp_lock_release(true); | |
49dfe2a6 | 705 | |
6a4e2451 TG |
706 | /* |
707 | * If we are up and running, use the hotplug thread. For early calls | |
708 | * we invoke the thread function directly. | |
709 | */ | |
710 | if (!st->thread) | |
96abb968 | 711 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 712 | |
4dddfb5f PZ |
713 | st->rollback = false; |
714 | st->last = NULL; | |
715 | ||
716 | st->node = node; | |
717 | st->bringup = bringup; | |
4cb28ced | 718 | st->cb_state = state; |
a724632c | 719 | st->single = true; |
a724632c | 720 | |
4dddfb5f | 721 | __cpuhp_kick_ap(st); |
4cb28ced | 722 | |
4cb28ced | 723 | /* |
4dddfb5f | 724 | * If we failed and did a partial, do a rollback. |
4cb28ced | 725 | */ |
4dddfb5f PZ |
726 | if ((ret = st->result) && st->last) { |
727 | st->rollback = true; | |
728 | st->bringup = !bringup; | |
729 | ||
730 | __cpuhp_kick_ap(st); | |
731 | } | |
732 | ||
1f7c70d6 TG |
733 | /* |
734 | * Clean up the leftovers so the next hotplug operation wont use stale | |
735 | * data. | |
736 | */ | |
737 | st->node = st->last = NULL; | |
4dddfb5f | 738 | return ret; |
1cf4f629 TG |
739 | } |
740 | ||
741 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
742 | { | |
743 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
744 | enum cpuhp_state prev_state = st->state; |
745 | int ret; | |
1cf4f629 | 746 | |
5f4b55e1 PZ |
747 | cpuhp_lock_acquire(false); |
748 | cpuhp_lock_release(false); | |
749 | ||
750 | cpuhp_lock_acquire(true); | |
751 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
752 | |
753 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
754 | ret = cpuhp_kick_ap(st, st->target); | |
755 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
756 | ||
757 | return ret; | |
4cb28ced TG |
758 | } |
759 | ||
760 | static struct smp_hotplug_thread cpuhp_threads = { | |
761 | .store = &cpuhp_state.thread, | |
762 | .create = &cpuhp_create, | |
763 | .thread_should_run = cpuhp_should_run, | |
764 | .thread_fn = cpuhp_thread_fun, | |
765 | .thread_comm = "cpuhp/%u", | |
766 | .selfparking = true, | |
767 | }; | |
768 | ||
769 | void __init cpuhp_threads_init(void) | |
770 | { | |
771 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
772 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
773 | } | |
774 | ||
777c6e0d | 775 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
776 | /** |
777 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
778 | * @cpu: a CPU id | |
779 | * | |
780 | * This function walks all processes, finds a valid mm struct for each one and | |
781 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
782 | * trivial, there are various non-obvious corner cases, which this function | |
783 | * tries to solve in a safe manner. | |
784 | * | |
785 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
786 | * be called only for an already offlined CPU. | |
787 | */ | |
cb79295e AV |
788 | void clear_tasks_mm_cpumask(int cpu) |
789 | { | |
790 | struct task_struct *p; | |
791 | ||
792 | /* | |
793 | * This function is called after the cpu is taken down and marked | |
794 | * offline, so its not like new tasks will ever get this cpu set in | |
795 | * their mm mask. -- Peter Zijlstra | |
796 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
797 | * full-fledged tasklist_lock. | |
798 | */ | |
e4cc2f87 | 799 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
800 | rcu_read_lock(); |
801 | for_each_process(p) { | |
802 | struct task_struct *t; | |
803 | ||
e4cc2f87 AV |
804 | /* |
805 | * Main thread might exit, but other threads may still have | |
806 | * a valid mm. Find one. | |
807 | */ | |
cb79295e AV |
808 | t = find_lock_task_mm(p); |
809 | if (!t) | |
810 | continue; | |
811 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
812 | task_unlock(t); | |
813 | } | |
814 | rcu_read_unlock(); | |
815 | } | |
816 | ||
1da177e4 | 817 | /* Take this CPU down. */ |
71cf5aee | 818 | static int take_cpu_down(void *_param) |
1da177e4 | 819 | { |
4baa0afc TG |
820 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
821 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 822 | int err, cpu = smp_processor_id(); |
724a8688 | 823 | int ret; |
1da177e4 | 824 | |
1da177e4 LT |
825 | /* Ensure this CPU doesn't handle any more interrupts. */ |
826 | err = __cpu_disable(); | |
827 | if (err < 0) | |
f3705136 | 828 | return err; |
1da177e4 | 829 | |
a724632c TG |
830 | /* |
831 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
832 | * do this step again. | |
833 | */ | |
834 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
835 | st->state--; | |
4baa0afc | 836 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
837 | for (; st->state > target; st->state--) { |
838 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
839 | /* | |
840 | * DYING must not fail! | |
841 | */ | |
842 | WARN_ON_ONCE(ret); | |
843 | } | |
4baa0afc | 844 | |
52c063d1 TG |
845 | /* Give up timekeeping duties */ |
846 | tick_handover_do_timer(); | |
14e568e7 | 847 | /* Park the stopper thread */ |
090e77c3 | 848 | stop_machine_park(cpu); |
f3705136 | 849 | return 0; |
1da177e4 LT |
850 | } |
851 | ||
98458172 | 852 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 853 | { |
e69aab13 | 854 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 855 | int err; |
1da177e4 | 856 | |
2a58c527 | 857 | /* Park the smpboot threads */ |
1cf4f629 TG |
858 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
859 | ||
6acce3ef | 860 | /* |
a8994181 TG |
861 | * Prevent irq alloc/free while the dying cpu reorganizes the |
862 | * interrupt affinities. | |
6acce3ef | 863 | */ |
a8994181 | 864 | irq_lock_sparse(); |
6acce3ef | 865 | |
a8994181 TG |
866 | /* |
867 | * So now all preempt/rcu users must observe !cpu_active(). | |
868 | */ | |
210e2133 | 869 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 870 | if (err) { |
3b9d6da6 | 871 | /* CPU refused to die */ |
a8994181 | 872 | irq_unlock_sparse(); |
3b9d6da6 SAS |
873 | /* Unpark the hotplug thread so we can rollback there */ |
874 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 875 | return err; |
8fa1d7d3 | 876 | } |
04321587 | 877 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 878 | |
48c5ccae | 879 | /* |
5b1ead68 BJ |
880 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
881 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 882 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
883 | * |
884 | * Wait for the stop thread to go away. | |
48c5ccae | 885 | */ |
5ebe7742 | 886 | wait_for_ap_thread(st, false); |
e69aab13 | 887 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 888 | |
a8994181 TG |
889 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
890 | irq_unlock_sparse(); | |
891 | ||
345527b1 | 892 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
893 | /* This actually kills the CPU. */ |
894 | __cpu_die(cpu); | |
895 | ||
a49b116d | 896 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 897 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
898 | return 0; |
899 | } | |
1da177e4 | 900 | |
71f87b2f TG |
901 | static void cpuhp_complete_idle_dead(void *arg) |
902 | { | |
903 | struct cpuhp_cpu_state *st = arg; | |
904 | ||
5ebe7742 | 905 | complete_ap_thread(st, false); |
71f87b2f TG |
906 | } |
907 | ||
e69aab13 TG |
908 | void cpuhp_report_idle_dead(void) |
909 | { | |
910 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
911 | ||
912 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 913 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
914 | st->state = CPUHP_AP_IDLE_DEAD; |
915 | /* | |
916 | * We cannot call complete after rcu_report_dead() so we delegate it | |
917 | * to an online cpu. | |
918 | */ | |
919 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
920 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
921 | } |
922 | ||
4dddfb5f PZ |
923 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
924 | { | |
925 | for (st->state++; st->state < st->target; st->state++) { | |
926 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
cff7d378 | 927 | |
4dddfb5f PZ |
928 | if (!step->skip_onerr) |
929 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
930 | } | |
931 | } | |
932 | ||
933 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
934 | enum cpuhp_state target) | |
935 | { | |
936 | enum cpuhp_state prev_state = st->state; | |
937 | int ret = 0; | |
938 | ||
939 | for (; st->state > target; st->state--) { | |
940 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
941 | if (ret) { | |
942 | st->target = prev_state; | |
b49a4576 TG |
943 | if (st->state < prev_state) |
944 | undo_cpu_down(cpu, st); | |
4dddfb5f PZ |
945 | break; |
946 | } | |
947 | } | |
948 | return ret; | |
949 | } | |
cff7d378 | 950 | |
98458172 | 951 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
952 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
953 | enum cpuhp_state target) | |
98458172 | 954 | { |
cff7d378 TG |
955 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
956 | int prev_state, ret = 0; | |
98458172 TG |
957 | |
958 | if (num_online_cpus() == 1) | |
959 | return -EBUSY; | |
960 | ||
757c989b | 961 | if (!cpu_present(cpu)) |
98458172 TG |
962 | return -EINVAL; |
963 | ||
8f553c49 | 964 | cpus_write_lock(); |
98458172 TG |
965 | |
966 | cpuhp_tasks_frozen = tasks_frozen; | |
967 | ||
4dddfb5f | 968 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
969 | /* |
970 | * If the current CPU state is in the range of the AP hotplug thread, | |
971 | * then we need to kick the thread. | |
972 | */ | |
8df3e07e | 973 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 974 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
975 | ret = cpuhp_kick_ap_work(cpu); |
976 | /* | |
977 | * The AP side has done the error rollback already. Just | |
978 | * return the error code.. | |
979 | */ | |
980 | if (ret) | |
981 | goto out; | |
982 | ||
983 | /* | |
984 | * We might have stopped still in the range of the AP hotplug | |
985 | * thread. Nothing to do anymore. | |
986 | */ | |
8df3e07e | 987 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 988 | goto out; |
4dddfb5f PZ |
989 | |
990 | st->target = target; | |
1cf4f629 TG |
991 | } |
992 | /* | |
8df3e07e | 993 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
994 | * to do the further cleanups. |
995 | */ | |
a724632c | 996 | ret = cpuhp_down_callbacks(cpu, st, target); |
b49a4576 | 997 | if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
998 | cpuhp_reset_state(st, prev_state); |
999 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 1000 | } |
98458172 | 1001 | |
1cf4f629 | 1002 | out: |
8f553c49 | 1003 | cpus_write_unlock(); |
941154bd TG |
1004 | /* |
1005 | * Do post unplug cleanup. This is still protected against | |
1006 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1007 | */ | |
1008 | lockup_detector_cleanup(); | |
fc8944e3 | 1009 | arch_smt_update(); |
cff7d378 | 1010 | return ret; |
e3920fb4 RW |
1011 | } |
1012 | ||
97127f50 TG |
1013 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1014 | { | |
1015 | if (cpu_hotplug_disabled) | |
1016 | return -EBUSY; | |
1017 | return _cpu_down(cpu, 0, target); | |
1018 | } | |
1019 | ||
af1f4045 | 1020 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1021 | { |
9ea09af3 | 1022 | int err; |
e3920fb4 | 1023 | |
d221938c | 1024 | cpu_maps_update_begin(); |
97127f50 | 1025 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1026 | cpu_maps_update_done(); |
1da177e4 LT |
1027 | return err; |
1028 | } | |
4dddfb5f | 1029 | |
af1f4045 TG |
1030 | int cpu_down(unsigned int cpu) |
1031 | { | |
1032 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1033 | } | |
b62b8ef9 | 1034 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f PZ |
1035 | |
1036 | #else | |
1037 | #define takedown_cpu NULL | |
1da177e4 LT |
1038 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1039 | ||
4baa0afc | 1040 | /** |
ee1e714b | 1041 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1042 | * @cpu: cpu that just started |
1043 | * | |
4baa0afc TG |
1044 | * It must be called by the arch code on the new cpu, before the new cpu |
1045 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1046 | */ | |
1047 | void notify_cpu_starting(unsigned int cpu) | |
1048 | { | |
1049 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1050 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1051 | int ret; |
4baa0afc | 1052 | |
0c6d4576 | 1053 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
3762ba90 | 1054 | st->booted_once = true; |
4baa0afc | 1055 | while (st->state < target) { |
4baa0afc | 1056 | st->state++; |
724a8688 PZ |
1057 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1058 | /* | |
1059 | * STARTING must not fail! | |
1060 | */ | |
1061 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1062 | } |
1063 | } | |
1064 | ||
949338e3 | 1065 | /* |
9cd4f1a4 TG |
1066 | * Called from the idle task. Wake up the controlling task which brings the |
1067 | * stopper and the hotplug thread of the upcoming CPU up and then delegates | |
1068 | * the rest of the online bringup to the hotplug thread. | |
949338e3 | 1069 | */ |
8df3e07e | 1070 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1071 | { |
8df3e07e | 1072 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1073 | |
1074 | /* Happens for the boot cpu */ | |
1075 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1076 | return; | |
1077 | ||
1078 | st->state = CPUHP_AP_ONLINE_IDLE; | |
5ebe7742 | 1079 | complete_ap_thread(st, true); |
949338e3 TG |
1080 | } |
1081 | ||
e3920fb4 | 1082 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1083 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1084 | { |
cff7d378 | 1085 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1086 | struct task_struct *idle; |
2e1a3483 | 1087 | int ret = 0; |
1da177e4 | 1088 | |
8f553c49 | 1089 | cpus_write_lock(); |
38498a67 | 1090 | |
757c989b | 1091 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1092 | ret = -EINVAL; |
1093 | goto out; | |
1094 | } | |
1095 | ||
757c989b TG |
1096 | /* |
1097 | * The caller of do_cpu_up might have raced with another | |
1098 | * caller. Ignore it for now. | |
1099 | */ | |
1100 | if (st->state >= target) | |
38498a67 | 1101 | goto out; |
757c989b TG |
1102 | |
1103 | if (st->state == CPUHP_OFFLINE) { | |
1104 | /* Let it fail before we try to bring the cpu up */ | |
1105 | idle = idle_thread_get(cpu); | |
1106 | if (IS_ERR(idle)) { | |
1107 | ret = PTR_ERR(idle); | |
1108 | goto out; | |
1109 | } | |
3bb5d2ee | 1110 | } |
38498a67 | 1111 | |
ba997462 TG |
1112 | cpuhp_tasks_frozen = tasks_frozen; |
1113 | ||
4dddfb5f | 1114 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1115 | /* |
1116 | * If the current CPU state is in the range of the AP hotplug thread, | |
1117 | * then we need to kick the thread once more. | |
1118 | */ | |
8df3e07e | 1119 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1120 | ret = cpuhp_kick_ap_work(cpu); |
1121 | /* | |
1122 | * The AP side has done the error rollback already. Just | |
1123 | * return the error code.. | |
1124 | */ | |
1125 | if (ret) | |
1126 | goto out; | |
1127 | } | |
1128 | ||
1129 | /* | |
1130 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1131 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1132 | * responsible for bringing it up to the target state. |
1133 | */ | |
8df3e07e | 1134 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1135 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1136 | out: |
8f553c49 | 1137 | cpus_write_unlock(); |
fc8944e3 | 1138 | arch_smt_update(); |
e3920fb4 RW |
1139 | return ret; |
1140 | } | |
1141 | ||
af1f4045 | 1142 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1143 | { |
1144 | int err = 0; | |
cf23422b | 1145 | |
e0b582ec | 1146 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1147 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1148 | cpu); | |
87d5e023 | 1149 | #if defined(CONFIG_IA64) |
84117da5 | 1150 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1151 | #endif |
1152 | return -EINVAL; | |
1153 | } | |
e3920fb4 | 1154 | |
01b0f197 TK |
1155 | err = try_online_node(cpu_to_node(cpu)); |
1156 | if (err) | |
1157 | return err; | |
cf23422b | 1158 | |
d221938c | 1159 | cpu_maps_update_begin(); |
e761b772 MK |
1160 | |
1161 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1162 | err = -EBUSY; |
e761b772 MK |
1163 | goto out; |
1164 | } | |
47b4c679 TG |
1165 | if (!cpu_smt_allowed(cpu)) { |
1166 | err = -EPERM; | |
1167 | goto out; | |
1168 | } | |
e761b772 | 1169 | |
af1f4045 | 1170 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1171 | out: |
d221938c | 1172 | cpu_maps_update_done(); |
e3920fb4 RW |
1173 | return err; |
1174 | } | |
af1f4045 TG |
1175 | |
1176 | int cpu_up(unsigned int cpu) | |
1177 | { | |
1178 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1179 | } | |
a513f6ba | 1180 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1181 | |
f3de4be9 | 1182 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1183 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1184 | |
d391e552 | 1185 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1186 | { |
d391e552 | 1187 | int cpu, error = 0; |
e3920fb4 | 1188 | |
d221938c | 1189 | cpu_maps_update_begin(); |
d391e552 JM |
1190 | if (!cpu_online(primary)) |
1191 | primary = cpumask_first(cpu_online_mask); | |
9ee349ad XF |
1192 | /* |
1193 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1194 | * with the userspace trying to use the CPU hotplug at the same time |
1195 | */ | |
e0b582ec | 1196 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1197 | |
84117da5 | 1198 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1199 | for_each_online_cpu(cpu) { |
d391e552 | 1200 | if (cpu == primary) |
e3920fb4 | 1201 | continue; |
bb3632c6 | 1202 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1203 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1204 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1205 | if (!error) |
e0b582ec | 1206 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1207 | else { |
84117da5 | 1208 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1209 | break; |
1210 | } | |
1211 | } | |
86886e55 | 1212 | |
89af7ba5 | 1213 | if (!error) |
e3920fb4 | 1214 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1215 | else |
84117da5 | 1216 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1217 | |
1218 | /* | |
1219 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1220 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1221 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1222 | */ | |
1223 | cpu_hotplug_disabled++; | |
1224 | ||
d221938c | 1225 | cpu_maps_update_done(); |
e3920fb4 RW |
1226 | return error; |
1227 | } | |
1228 | ||
d0af9eed SS |
1229 | void __weak arch_enable_nonboot_cpus_begin(void) |
1230 | { | |
1231 | } | |
1232 | ||
1233 | void __weak arch_enable_nonboot_cpus_end(void) | |
1234 | { | |
1235 | } | |
1236 | ||
71cf5aee | 1237 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1238 | { |
1239 | int cpu, error; | |
1240 | ||
1241 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1242 | cpu_maps_update_begin(); |
01b41159 | 1243 | __cpu_hotplug_enable(); |
e0b582ec | 1244 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1245 | goto out; |
e3920fb4 | 1246 | |
84117da5 | 1247 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1248 | |
1249 | arch_enable_nonboot_cpus_begin(); | |
1250 | ||
e0b582ec | 1251 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1252 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1253 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1254 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1255 | if (!error) { |
84117da5 | 1256 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1257 | continue; |
1258 | } | |
84117da5 | 1259 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1260 | } |
d0af9eed SS |
1261 | |
1262 | arch_enable_nonboot_cpus_end(); | |
1263 | ||
e0b582ec | 1264 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1265 | out: |
d221938c | 1266 | cpu_maps_update_done(); |
1da177e4 | 1267 | } |
e0b582ec | 1268 | |
d7268a31 | 1269 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1270 | { |
1271 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1272 | return -ENOMEM; | |
1273 | return 0; | |
1274 | } | |
1275 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1276 | |
79cfbdfa SB |
1277 | /* |
1278 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1279 | * ensure that the state of the system with respect to the tasks being frozen | |
1280 | * or not, as reported by the notification, remains unchanged *throughout the | |
1281 | * duration* of the execution of the callbacks. | |
1282 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1283 | * | |
1284 | * This synchronization is implemented by mutually excluding regular CPU | |
1285 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1286 | * Hibernate notifications. | |
1287 | */ | |
1288 | static int | |
1289 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1290 | unsigned long action, void *ptr) | |
1291 | { | |
1292 | switch (action) { | |
1293 | ||
1294 | case PM_SUSPEND_PREPARE: | |
1295 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1296 | cpu_hotplug_disable(); |
79cfbdfa SB |
1297 | break; |
1298 | ||
1299 | case PM_POST_SUSPEND: | |
1300 | case PM_POST_HIBERNATION: | |
16e53dbf | 1301 | cpu_hotplug_enable(); |
79cfbdfa SB |
1302 | break; |
1303 | ||
1304 | default: | |
1305 | return NOTIFY_DONE; | |
1306 | } | |
1307 | ||
1308 | return NOTIFY_OK; | |
1309 | } | |
1310 | ||
1311 | ||
d7268a31 | 1312 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1313 | { |
6e32d479 FY |
1314 | /* |
1315 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1316 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1317 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1318 | */ | |
79cfbdfa SB |
1319 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1320 | return 0; | |
1321 | } | |
1322 | core_initcall(cpu_hotplug_pm_sync_init); | |
1323 | ||
f3de4be9 | 1324 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1325 | |
8ce371f9 PZ |
1326 | int __boot_cpu_id; |
1327 | ||
68f4f1ec | 1328 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1329 | |
cff7d378 TG |
1330 | /* Boot processor state steps */ |
1331 | static struct cpuhp_step cpuhp_bp_states[] = { | |
1332 | [CPUHP_OFFLINE] = { | |
1333 | .name = "offline", | |
3c1627e9 TG |
1334 | .startup.single = NULL, |
1335 | .teardown.single = NULL, | |
cff7d378 TG |
1336 | }, |
1337 | #ifdef CONFIG_SMP | |
1338 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1339 | .name = "threads:prepare", |
3c1627e9 TG |
1340 | .startup.single = smpboot_create_threads, |
1341 | .teardown.single = NULL, | |
757c989b | 1342 | .cant_stop = true, |
cff7d378 | 1343 | }, |
00e16c3d | 1344 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1345 | .name = "perf:prepare", |
1346 | .startup.single = perf_event_init_cpu, | |
1347 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1348 | }, |
7ee681b2 | 1349 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1350 | .name = "workqueue:prepare", |
1351 | .startup.single = workqueue_prepare_cpu, | |
1352 | .teardown.single = NULL, | |
7ee681b2 | 1353 | }, |
27590dc1 | 1354 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1355 | .name = "hrtimers:prepare", |
1356 | .startup.single = hrtimers_prepare_cpu, | |
1357 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1358 | }, |
31487f83 | 1359 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1360 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1361 | .startup.single = smpcfd_prepare_cpu, |
1362 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1363 | }, |
e6d4989a RW |
1364 | [CPUHP_RELAY_PREPARE] = { |
1365 | .name = "relay:prepare", | |
1366 | .startup.single = relay_prepare_cpu, | |
1367 | .teardown.single = NULL, | |
1368 | }, | |
6731d4f1 SAS |
1369 | [CPUHP_SLAB_PREPARE] = { |
1370 | .name = "slab:prepare", | |
1371 | .startup.single = slab_prepare_cpu, | |
1372 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1373 | }, |
4df83742 | 1374 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1375 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1376 | .startup.single = rcutree_prepare_cpu, |
1377 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1378 | }, |
4fae16df RC |
1379 | /* |
1380 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1381 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1382 | * otherwise a RCU stall occurs. | |
1383 | */ | |
26456f87 | 1384 | [CPUHP_TIMERS_PREPARE] = { |
3c1627e9 | 1385 | .name = "timers:dead", |
26456f87 | 1386 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1387 | .teardown.single = timers_dead_cpu, |
4fae16df | 1388 | }, |
d10ef6f9 | 1389 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1390 | [CPUHP_BRINGUP_CPU] = { |
1391 | .name = "cpu:bringup", | |
3c1627e9 TG |
1392 | .startup.single = bringup_cpu, |
1393 | .teardown.single = NULL, | |
757c989b | 1394 | .cant_stop = true, |
4baa0afc | 1395 | }, |
d10ef6f9 TG |
1396 | /* |
1397 | * Handled on controll processor until the plugged processor manages | |
1398 | * this itself. | |
1399 | */ | |
4baa0afc TG |
1400 | [CPUHP_TEARDOWN_CPU] = { |
1401 | .name = "cpu:teardown", | |
3c1627e9 TG |
1402 | .startup.single = NULL, |
1403 | .teardown.single = takedown_cpu, | |
757c989b | 1404 | .cant_stop = true, |
cff7d378 | 1405 | }, |
a7c73414 TG |
1406 | #else |
1407 | [CPUHP_BRINGUP_CPU] = { }, | |
cff7d378 | 1408 | #endif |
cff7d378 TG |
1409 | }; |
1410 | ||
4baa0afc TG |
1411 | /* Application processor state steps */ |
1412 | static struct cpuhp_step cpuhp_ap_states[] = { | |
1413 | #ifdef CONFIG_SMP | |
d10ef6f9 TG |
1414 | /* Final state before CPU kills itself */ |
1415 | [CPUHP_AP_IDLE_DEAD] = { | |
1416 | .name = "idle:dead", | |
1417 | }, | |
1418 | /* | |
1419 | * Last state before CPU enters the idle loop to die. Transient state | |
1420 | * for synchronization. | |
1421 | */ | |
1422 | [CPUHP_AP_OFFLINE] = { | |
1423 | .name = "ap:offline", | |
1424 | .cant_stop = true, | |
1425 | }, | |
9cf7243d TG |
1426 | /* First state is scheduler control. Interrupts are disabled */ |
1427 | [CPUHP_AP_SCHED_STARTING] = { | |
1428 | .name = "sched:starting", | |
3c1627e9 TG |
1429 | .startup.single = sched_cpu_starting, |
1430 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1431 | }, |
4df83742 | 1432 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1433 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1434 | .startup.single = NULL, |
1435 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1436 | }, |
46febd37 LJ |
1437 | [CPUHP_AP_SMPCFD_DYING] = { |
1438 | .name = "smpcfd:dying", | |
1439 | .startup.single = NULL, | |
1440 | .teardown.single = smpcfd_dying_cpu, | |
1441 | }, | |
d10ef6f9 TG |
1442 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1443 | * state for synchronsization */ | |
1444 | [CPUHP_AP_ONLINE] = { | |
1445 | .name = "ap:online", | |
1446 | }, | |
1447 | /* Handle smpboot threads park/unpark */ | |
1cf4f629 | 1448 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1449 | .name = "smpboot/threads:online", |
3c1627e9 | 1450 | .startup.single = smpboot_unpark_threads, |
a82cd3a3 | 1451 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1452 | }, |
c5cb83bb TG |
1453 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1454 | .name = "irq/affinity:online", | |
1455 | .startup.single = irq_affinity_online_cpu, | |
1456 | .teardown.single = NULL, | |
1457 | }, | |
00e16c3d | 1458 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1459 | .name = "perf:online", |
1460 | .startup.single = perf_event_init_cpu, | |
1461 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1462 | }, |
7ee681b2 | 1463 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1464 | .name = "workqueue:online", |
1465 | .startup.single = workqueue_online_cpu, | |
1466 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1467 | }, |
4df83742 | 1468 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1469 | .name = "RCU/tree:online", |
3c1627e9 TG |
1470 | .startup.single = rcutree_online_cpu, |
1471 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1472 | }, |
4baa0afc | 1473 | #endif |
d10ef6f9 TG |
1474 | /* |
1475 | * The dynamically registered state space is here | |
1476 | */ | |
1477 | ||
aaddd7d1 TG |
1478 | #ifdef CONFIG_SMP |
1479 | /* Last state is scheduler control setting the cpu active */ | |
1480 | [CPUHP_AP_ACTIVE] = { | |
1481 | .name = "sched:active", | |
3c1627e9 TG |
1482 | .startup.single = sched_cpu_activate, |
1483 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1484 | }, |
1485 | #endif | |
1486 | ||
d10ef6f9 | 1487 | /* CPU is fully up and running. */ |
4baa0afc TG |
1488 | [CPUHP_ONLINE] = { |
1489 | .name = "online", | |
3c1627e9 TG |
1490 | .startup.single = NULL, |
1491 | .teardown.single = NULL, | |
4baa0afc TG |
1492 | }, |
1493 | }; | |
1494 | ||
5b7aa87e TG |
1495 | /* Sanity check for callbacks */ |
1496 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1497 | { | |
1498 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1499 | return -EINVAL; | |
1500 | return 0; | |
1501 | } | |
1502 | ||
dc280d93 TG |
1503 | /* |
1504 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1505 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1506 | * by having no name assigned. | |
1507 | */ | |
1508 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1509 | { | |
4205e478 TG |
1510 | enum cpuhp_state i, end; |
1511 | struct cpuhp_step *step; | |
dc280d93 | 1512 | |
4205e478 TG |
1513 | switch (state) { |
1514 | case CPUHP_AP_ONLINE_DYN: | |
1515 | step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN; | |
1516 | end = CPUHP_AP_ONLINE_DYN_END; | |
1517 | break; | |
1518 | case CPUHP_BP_PREPARE_DYN: | |
1519 | step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN; | |
1520 | end = CPUHP_BP_PREPARE_DYN_END; | |
1521 | break; | |
1522 | default: | |
1523 | return -EINVAL; | |
1524 | } | |
1525 | ||
1526 | for (i = state; i <= end; i++, step++) { | |
1527 | if (!step->name) | |
dc280d93 TG |
1528 | return i; |
1529 | } | |
1530 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1531 | return -ENOSPC; | |
1532 | } | |
1533 | ||
1534 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1535 | int (*startup)(unsigned int cpu), | |
1536 | int (*teardown)(unsigned int cpu), | |
1537 | bool multi_instance) | |
5b7aa87e TG |
1538 | { |
1539 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1540 | struct cpuhp_step *sp; | |
dc280d93 | 1541 | int ret = 0; |
5b7aa87e | 1542 | |
0c96b273 EB |
1543 | /* |
1544 | * If name is NULL, then the state gets removed. | |
1545 | * | |
1546 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1547 | * the first allocation from these dynamic ranges, so the removal | |
1548 | * would trigger a new allocation and clear the wrong (already | |
1549 | * empty) state, leaving the callbacks of the to be cleared state | |
1550 | * dangling, which causes wreckage on the next hotplug operation. | |
1551 | */ | |
1552 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1553 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1554 | ret = cpuhp_reserve_state(state); |
1555 | if (ret < 0) | |
dc434e05 | 1556 | return ret; |
dc280d93 TG |
1557 | state = ret; |
1558 | } | |
5b7aa87e | 1559 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1560 | if (name && sp->name) |
1561 | return -EBUSY; | |
1562 | ||
3c1627e9 TG |
1563 | sp->startup.single = startup; |
1564 | sp->teardown.single = teardown; | |
5b7aa87e | 1565 | sp->name = name; |
cf392d10 TG |
1566 | sp->multi_instance = multi_instance; |
1567 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1568 | return ret; |
5b7aa87e TG |
1569 | } |
1570 | ||
1571 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1572 | { | |
3c1627e9 | 1573 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1574 | } |
1575 | ||
5b7aa87e TG |
1576 | /* |
1577 | * Call the startup/teardown function for a step either on the AP or | |
1578 | * on the current CPU. | |
1579 | */ | |
cf392d10 TG |
1580 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1581 | struct hlist_node *node) | |
5b7aa87e | 1582 | { |
a724632c | 1583 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1584 | int ret; |
1585 | ||
4dddfb5f PZ |
1586 | /* |
1587 | * If there's nothing to do, we done. | |
1588 | * Relies on the union for multi_instance. | |
1589 | */ | |
3c1627e9 TG |
1590 | if ((bringup && !sp->startup.single) || |
1591 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1592 | return 0; |
5b7aa87e TG |
1593 | /* |
1594 | * The non AP bound callbacks can fail on bringup. On teardown | |
1595 | * e.g. module removal we crash for now. | |
1596 | */ | |
1cf4f629 TG |
1597 | #ifdef CONFIG_SMP |
1598 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1599 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1600 | else |
96abb968 | 1601 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1602 | #else |
96abb968 | 1603 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1604 | #endif |
5b7aa87e TG |
1605 | BUG_ON(ret && !bringup); |
1606 | return ret; | |
1607 | } | |
1608 | ||
1609 | /* | |
1610 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1611 | * | |
1612 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1613 | */ | |
1614 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1615 | struct hlist_node *node) |
5b7aa87e TG |
1616 | { |
1617 | int cpu; | |
1618 | ||
5b7aa87e TG |
1619 | /* Roll back the already executed steps on the other cpus */ |
1620 | for_each_present_cpu(cpu) { | |
1621 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1622 | int cpustate = st->state; | |
1623 | ||
1624 | if (cpu >= failedcpu) | |
1625 | break; | |
1626 | ||
1627 | /* Did we invoke the startup call on that cpu ? */ | |
1628 | if (cpustate >= state) | |
cf392d10 | 1629 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1630 | } |
1631 | } | |
1632 | ||
9805c673 TG |
1633 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1634 | struct hlist_node *node, | |
1635 | bool invoke) | |
cf392d10 TG |
1636 | { |
1637 | struct cpuhp_step *sp; | |
1638 | int cpu; | |
1639 | int ret; | |
1640 | ||
9805c673 TG |
1641 | lockdep_assert_cpus_held(); |
1642 | ||
cf392d10 TG |
1643 | sp = cpuhp_get_step(state); |
1644 | if (sp->multi_instance == false) | |
1645 | return -EINVAL; | |
1646 | ||
dc434e05 | 1647 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1648 | |
3c1627e9 | 1649 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1650 | goto add_node; |
1651 | ||
1652 | /* | |
1653 | * Try to call the startup callback for each present cpu | |
1654 | * depending on the hotplug state of the cpu. | |
1655 | */ | |
1656 | for_each_present_cpu(cpu) { | |
1657 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1658 | int cpustate = st->state; | |
1659 | ||
1660 | if (cpustate < state) | |
1661 | continue; | |
1662 | ||
1663 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1664 | if (ret) { | |
3c1627e9 | 1665 | if (sp->teardown.multi) |
cf392d10 | 1666 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1667 | goto unlock; |
cf392d10 TG |
1668 | } |
1669 | } | |
1670 | add_node: | |
1671 | ret = 0; | |
cf392d10 | 1672 | hlist_add_head(node, &sp->list); |
dc434e05 | 1673 | unlock: |
cf392d10 | 1674 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1675 | return ret; |
1676 | } | |
1677 | ||
1678 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1679 | bool invoke) | |
1680 | { | |
1681 | int ret; | |
1682 | ||
1683 | cpus_read_lock(); | |
1684 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1685 | cpus_read_unlock(); |
cf392d10 TG |
1686 | return ret; |
1687 | } | |
1688 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1689 | ||
5b7aa87e | 1690 | /** |
71def423 | 1691 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1692 | * @state: The state to setup |
1693 | * @invoke: If true, the startup function is invoked for cpus where | |
1694 | * cpu state >= @state | |
1695 | * @startup: startup callback function | |
1696 | * @teardown: teardown callback function | |
1697 | * @multi_instance: State is set up for multiple instances which get | |
1698 | * added afterwards. | |
5b7aa87e | 1699 | * |
71def423 | 1700 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1701 | * Returns: |
1702 | * On success: | |
1703 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1704 | * 0 for all other states | |
1705 | * On failure: proper (negative) error code | |
5b7aa87e | 1706 | */ |
71def423 SAS |
1707 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1708 | const char *name, bool invoke, | |
1709 | int (*startup)(unsigned int cpu), | |
1710 | int (*teardown)(unsigned int cpu), | |
1711 | bool multi_instance) | |
5b7aa87e TG |
1712 | { |
1713 | int cpu, ret = 0; | |
b9d9d691 | 1714 | bool dynstate; |
5b7aa87e | 1715 | |
71def423 SAS |
1716 | lockdep_assert_cpus_held(); |
1717 | ||
5b7aa87e TG |
1718 | if (cpuhp_cb_check(state) || !name) |
1719 | return -EINVAL; | |
1720 | ||
dc434e05 | 1721 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1722 | |
dc280d93 TG |
1723 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1724 | multi_instance); | |
5b7aa87e | 1725 | |
b9d9d691 TG |
1726 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1727 | if (ret > 0 && dynstate) { | |
1728 | state = ret; | |
1729 | ret = 0; | |
1730 | } | |
1731 | ||
dc280d93 | 1732 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1733 | goto out; |
1734 | ||
1735 | /* | |
1736 | * Try to call the startup callback for each present cpu | |
1737 | * depending on the hotplug state of the cpu. | |
1738 | */ | |
1739 | for_each_present_cpu(cpu) { | |
1740 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1741 | int cpustate = st->state; | |
1742 | ||
1743 | if (cpustate < state) | |
1744 | continue; | |
1745 | ||
cf392d10 | 1746 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1747 | if (ret) { |
a724632c | 1748 | if (teardown) |
cf392d10 TG |
1749 | cpuhp_rollback_install(cpu, state, NULL); |
1750 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1751 | goto out; |
1752 | } | |
1753 | } | |
1754 | out: | |
dc434e05 | 1755 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1756 | /* |
1757 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1758 | * dynamically allocated state in case of success. | |
1759 | */ | |
b9d9d691 | 1760 | if (!ret && dynstate) |
5b7aa87e TG |
1761 | return state; |
1762 | return ret; | |
1763 | } | |
71def423 SAS |
1764 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1765 | ||
1766 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1767 | const char *name, bool invoke, | |
1768 | int (*startup)(unsigned int cpu), | |
1769 | int (*teardown)(unsigned int cpu), | |
1770 | bool multi_instance) | |
1771 | { | |
1772 | int ret; | |
1773 | ||
1774 | cpus_read_lock(); | |
1775 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1776 | teardown, multi_instance); | |
1777 | cpus_read_unlock(); | |
1778 | return ret; | |
1779 | } | |
5b7aa87e TG |
1780 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1781 | ||
cf392d10 TG |
1782 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1783 | struct hlist_node *node, bool invoke) | |
1784 | { | |
1785 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1786 | int cpu; | |
1787 | ||
1788 | BUG_ON(cpuhp_cb_check(state)); | |
1789 | ||
1790 | if (!sp->multi_instance) | |
1791 | return -EINVAL; | |
1792 | ||
8f553c49 | 1793 | cpus_read_lock(); |
dc434e05 SAS |
1794 | mutex_lock(&cpuhp_state_mutex); |
1795 | ||
cf392d10 TG |
1796 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1797 | goto remove; | |
1798 | /* | |
1799 | * Call the teardown callback for each present cpu depending | |
1800 | * on the hotplug state of the cpu. This function is not | |
1801 | * allowed to fail currently! | |
1802 | */ | |
1803 | for_each_present_cpu(cpu) { | |
1804 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1805 | int cpustate = st->state; | |
1806 | ||
1807 | if (cpustate >= state) | |
1808 | cpuhp_issue_call(cpu, state, false, node); | |
1809 | } | |
1810 | ||
1811 | remove: | |
cf392d10 TG |
1812 | hlist_del(node); |
1813 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1814 | cpus_read_unlock(); |
cf392d10 TG |
1815 | |
1816 | return 0; | |
1817 | } | |
1818 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1819 | |
5b7aa87e | 1820 | /** |
71def423 | 1821 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1822 | * @state: The state to remove |
1823 | * @invoke: If true, the teardown function is invoked for cpus where | |
1824 | * cpu state >= @state | |
1825 | * | |
71def423 | 1826 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1827 | * The teardown callback is currently not allowed to fail. Think |
1828 | * about module removal! | |
1829 | */ | |
71def423 | 1830 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1831 | { |
cf392d10 | 1832 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1833 | int cpu; |
1834 | ||
1835 | BUG_ON(cpuhp_cb_check(state)); | |
1836 | ||
71def423 | 1837 | lockdep_assert_cpus_held(); |
5b7aa87e | 1838 | |
dc434e05 | 1839 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1840 | if (sp->multi_instance) { |
1841 | WARN(!hlist_empty(&sp->list), | |
1842 | "Error: Removing state %d which has instances left.\n", | |
1843 | state); | |
1844 | goto remove; | |
1845 | } | |
1846 | ||
a724632c | 1847 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1848 | goto remove; |
1849 | ||
1850 | /* | |
1851 | * Call the teardown callback for each present cpu depending | |
1852 | * on the hotplug state of the cpu. This function is not | |
1853 | * allowed to fail currently! | |
1854 | */ | |
1855 | for_each_present_cpu(cpu) { | |
1856 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1857 | int cpustate = st->state; | |
1858 | ||
1859 | if (cpustate >= state) | |
cf392d10 | 1860 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1861 | } |
1862 | remove: | |
cf392d10 | 1863 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1864 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1865 | } |
1866 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1867 | ||
1868 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1869 | { | |
1870 | cpus_read_lock(); | |
1871 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 1872 | cpus_read_unlock(); |
5b7aa87e TG |
1873 | } |
1874 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1875 | ||
98f8cdce TG |
1876 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1877 | static ssize_t show_cpuhp_state(struct device *dev, | |
1878 | struct device_attribute *attr, char *buf) | |
1879 | { | |
1880 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1881 | ||
1882 | return sprintf(buf, "%d\n", st->state); | |
1883 | } | |
1884 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1885 | ||
757c989b TG |
1886 | static ssize_t write_cpuhp_target(struct device *dev, |
1887 | struct device_attribute *attr, | |
1888 | const char *buf, size_t count) | |
1889 | { | |
1890 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1891 | struct cpuhp_step *sp; | |
1892 | int target, ret; | |
1893 | ||
1894 | ret = kstrtoint(buf, 10, &target); | |
1895 | if (ret) | |
1896 | return ret; | |
1897 | ||
1898 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1899 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1900 | return -EINVAL; | |
1901 | #else | |
1902 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1903 | return -EINVAL; | |
1904 | #endif | |
1905 | ||
1906 | ret = lock_device_hotplug_sysfs(); | |
1907 | if (ret) | |
1908 | return ret; | |
1909 | ||
1910 | mutex_lock(&cpuhp_state_mutex); | |
1911 | sp = cpuhp_get_step(target); | |
1912 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1913 | mutex_unlock(&cpuhp_state_mutex); | |
1914 | if (ret) | |
40da1b11 | 1915 | goto out; |
757c989b TG |
1916 | |
1917 | if (st->state < target) | |
1918 | ret = do_cpu_up(dev->id, target); | |
1919 | else | |
1920 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 1921 | out: |
757c989b TG |
1922 | unlock_device_hotplug(); |
1923 | return ret ? ret : count; | |
1924 | } | |
1925 | ||
98f8cdce TG |
1926 | static ssize_t show_cpuhp_target(struct device *dev, |
1927 | struct device_attribute *attr, char *buf) | |
1928 | { | |
1929 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1930 | ||
1931 | return sprintf(buf, "%d\n", st->target); | |
1932 | } | |
757c989b | 1933 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 1934 | |
1db49484 PZ |
1935 | |
1936 | static ssize_t write_cpuhp_fail(struct device *dev, | |
1937 | struct device_attribute *attr, | |
1938 | const char *buf, size_t count) | |
1939 | { | |
1940 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1941 | struct cpuhp_step *sp; | |
1942 | int fail, ret; | |
1943 | ||
1944 | ret = kstrtoint(buf, 10, &fail); | |
1945 | if (ret) | |
1946 | return ret; | |
1947 | ||
63891db0 ET |
1948 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
1949 | return -EINVAL; | |
1950 | ||
1db49484 PZ |
1951 | /* |
1952 | * Cannot fail STARTING/DYING callbacks. | |
1953 | */ | |
1954 | if (cpuhp_is_atomic_state(fail)) | |
1955 | return -EINVAL; | |
1956 | ||
1957 | /* | |
1958 | * Cannot fail anything that doesn't have callbacks. | |
1959 | */ | |
1960 | mutex_lock(&cpuhp_state_mutex); | |
1961 | sp = cpuhp_get_step(fail); | |
1962 | if (!sp->startup.single && !sp->teardown.single) | |
1963 | ret = -EINVAL; | |
1964 | mutex_unlock(&cpuhp_state_mutex); | |
1965 | if (ret) | |
1966 | return ret; | |
1967 | ||
1968 | st->fail = fail; | |
1969 | ||
1970 | return count; | |
1971 | } | |
1972 | ||
1973 | static ssize_t show_cpuhp_fail(struct device *dev, | |
1974 | struct device_attribute *attr, char *buf) | |
1975 | { | |
1976 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1977 | ||
1978 | return sprintf(buf, "%d\n", st->fail); | |
1979 | } | |
1980 | ||
1981 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
1982 | ||
98f8cdce TG |
1983 | static struct attribute *cpuhp_cpu_attrs[] = { |
1984 | &dev_attr_state.attr, | |
1985 | &dev_attr_target.attr, | |
1db49484 | 1986 | &dev_attr_fail.attr, |
98f8cdce TG |
1987 | NULL |
1988 | }; | |
1989 | ||
993647a2 | 1990 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
1991 | .attrs = cpuhp_cpu_attrs, |
1992 | .name = "hotplug", | |
1993 | NULL | |
1994 | }; | |
1995 | ||
1996 | static ssize_t show_cpuhp_states(struct device *dev, | |
1997 | struct device_attribute *attr, char *buf) | |
1998 | { | |
1999 | ssize_t cur, res = 0; | |
2000 | int i; | |
2001 | ||
2002 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2003 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2004 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2005 | ||
2006 | if (sp->name) { | |
2007 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2008 | buf += cur; | |
2009 | res += cur; | |
2010 | } | |
2011 | } | |
2012 | mutex_unlock(&cpuhp_state_mutex); | |
2013 | return res; | |
2014 | } | |
2015 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2016 | ||
2017 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2018 | &dev_attr_states.attr, | |
2019 | NULL | |
2020 | }; | |
2021 | ||
993647a2 | 2022 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2023 | .attrs = cpuhp_cpu_root_attrs, |
2024 | .name = "hotplug", | |
2025 | NULL | |
2026 | }; | |
2027 | ||
47b4c679 TG |
2028 | #ifdef CONFIG_HOTPLUG_SMT |
2029 | ||
2030 | static const char *smt_states[] = { | |
2031 | [CPU_SMT_ENABLED] = "on", | |
2032 | [CPU_SMT_DISABLED] = "off", | |
2033 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2034 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2035 | }; | |
2036 | ||
2037 | static ssize_t | |
2038 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2039 | { | |
2040 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); | |
2041 | } | |
2042 | ||
2043 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2044 | { | |
2045 | struct device *dev = get_cpu_device(cpu); | |
2046 | ||
2047 | dev->offline = true; | |
2048 | /* Tell user space about the state change */ | |
2049 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2050 | } | |
2051 | ||
b582c9f2 TG |
2052 | static void cpuhp_online_cpu_device(unsigned int cpu) |
2053 | { | |
2054 | struct device *dev = get_cpu_device(cpu); | |
2055 | ||
2056 | dev->offline = false; | |
2057 | /* Tell user space about the state change */ | |
2058 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2059 | } | |
2060 | ||
3e14fdad | 2061 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) |
47b4c679 TG |
2062 | { |
2063 | int cpu, ret = 0; | |
2064 | ||
2065 | cpu_maps_update_begin(); | |
2066 | for_each_online_cpu(cpu) { | |
2067 | if (topology_is_primary_thread(cpu)) | |
2068 | continue; | |
2069 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2070 | if (ret) | |
2071 | break; | |
2072 | /* | |
2073 | * As this needs to hold the cpu maps lock it's impossible | |
2074 | * to call device_offline() because that ends up calling | |
2075 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2076 | * needs to be held as this might race against in kernel | |
2077 | * abusers of the hotplug machinery (thermal management). | |
2078 | * | |
2079 | * So nothing would update device:offline state. That would | |
2080 | * leave the sysfs entry stale and prevent onlining after | |
2081 | * smt control has been changed to 'off' again. This is | |
2082 | * called under the sysfs hotplug lock, so it is properly | |
2083 | * serialized against the regular offline usage. | |
2084 | */ | |
2085 | cpuhp_offline_cpu_device(cpu); | |
2086 | } | |
7011f443 | 2087 | if (!ret) { |
47b4c679 | 2088 | cpu_smt_control = ctrlval; |
7011f443 JK |
2089 | arch_smt_update(); |
2090 | } | |
47b4c679 TG |
2091 | cpu_maps_update_done(); |
2092 | return ret; | |
2093 | } | |
2094 | ||
3e14fdad | 2095 | int cpuhp_smt_enable(void) |
47b4c679 | 2096 | { |
b582c9f2 TG |
2097 | int cpu, ret = 0; |
2098 | ||
47b4c679 TG |
2099 | cpu_maps_update_begin(); |
2100 | cpu_smt_control = CPU_SMT_ENABLED; | |
7011f443 | 2101 | arch_smt_update(); |
b582c9f2 TG |
2102 | for_each_present_cpu(cpu) { |
2103 | /* Skip online CPUs and CPUs on offline nodes */ | |
2104 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2105 | continue; | |
2106 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2107 | if (ret) | |
2108 | break; | |
2109 | /* See comment in cpuhp_smt_disable() */ | |
2110 | cpuhp_online_cpu_device(cpu); | |
2111 | } | |
47b4c679 | 2112 | cpu_maps_update_done(); |
b582c9f2 | 2113 | return ret; |
47b4c679 TG |
2114 | } |
2115 | ||
2116 | static ssize_t | |
2117 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2118 | const char *buf, size_t count) | |
2119 | { | |
2120 | int ctrlval, ret; | |
2121 | ||
2122 | if (sysfs_streq(buf, "on")) | |
2123 | ctrlval = CPU_SMT_ENABLED; | |
2124 | else if (sysfs_streq(buf, "off")) | |
2125 | ctrlval = CPU_SMT_DISABLED; | |
2126 | else if (sysfs_streq(buf, "forceoff")) | |
2127 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2128 | else | |
2129 | return -EINVAL; | |
2130 | ||
2131 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2132 | return -EPERM; | |
2133 | ||
2134 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2135 | return -ENODEV; | |
2136 | ||
2137 | ret = lock_device_hotplug_sysfs(); | |
2138 | if (ret) | |
2139 | return ret; | |
2140 | ||
2141 | if (ctrlval != cpu_smt_control) { | |
2142 | switch (ctrlval) { | |
2143 | case CPU_SMT_ENABLED: | |
b582c9f2 | 2144 | ret = cpuhp_smt_enable(); |
47b4c679 TG |
2145 | break; |
2146 | case CPU_SMT_DISABLED: | |
2147 | case CPU_SMT_FORCE_DISABLED: | |
2148 | ret = cpuhp_smt_disable(ctrlval); | |
2149 | break; | |
2150 | } | |
2151 | } | |
2152 | ||
2153 | unlock_device_hotplug(); | |
2154 | return ret ? ret : count; | |
2155 | } | |
2156 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); | |
2157 | ||
2158 | static ssize_t | |
2159 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2160 | { | |
2161 | bool active = topology_max_smt_threads() > 1; | |
2162 | ||
2163 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); | |
2164 | } | |
2165 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2166 | ||
2167 | static struct attribute *cpuhp_smt_attrs[] = { | |
2168 | &dev_attr_control.attr, | |
2169 | &dev_attr_active.attr, | |
2170 | NULL | |
2171 | }; | |
2172 | ||
2173 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2174 | .attrs = cpuhp_smt_attrs, | |
2175 | .name = "smt", | |
2176 | NULL | |
2177 | }; | |
2178 | ||
2179 | static int __init cpu_smt_state_init(void) | |
2180 | { | |
47b4c679 TG |
2181 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2182 | &cpuhp_smt_attr_group); | |
2183 | } | |
2184 | ||
2185 | #else | |
2186 | static inline int cpu_smt_state_init(void) { return 0; } | |
2187 | #endif | |
2188 | ||
98f8cdce TG |
2189 | static int __init cpuhp_sysfs_init(void) |
2190 | { | |
2191 | int cpu, ret; | |
2192 | ||
47b4c679 TG |
2193 | ret = cpu_smt_state_init(); |
2194 | if (ret) | |
2195 | return ret; | |
2196 | ||
98f8cdce TG |
2197 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2198 | &cpuhp_cpu_root_attr_group); | |
2199 | if (ret) | |
2200 | return ret; | |
2201 | ||
2202 | for_each_possible_cpu(cpu) { | |
2203 | struct device *dev = get_cpu_device(cpu); | |
2204 | ||
2205 | if (!dev) | |
2206 | continue; | |
2207 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2208 | if (ret) | |
2209 | return ret; | |
2210 | } | |
2211 | return 0; | |
2212 | } | |
2213 | device_initcall(cpuhp_sysfs_init); | |
2214 | #endif | |
2215 | ||
e56b3bc7 LT |
2216 | /* |
2217 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2218 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2219 | * | |
e0b582ec | 2220 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2221 | * mask value that has a single bit set only. |
2222 | */ | |
b8d317d1 | 2223 | |
e56b3bc7 | 2224 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2225 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2226 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2227 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2228 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2229 | |
e56b3bc7 LT |
2230 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2231 | ||
2232 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2233 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2234 | #if BITS_PER_LONG > 32 | |
2235 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2236 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2237 | #endif |
2238 | }; | |
e56b3bc7 | 2239 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2240 | |
2241 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2242 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2243 | |
2244 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2245 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2246 | = {CPU_BITS_ALL}; |
b3199c02 | 2247 | #else |
4b804c85 | 2248 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2249 | #endif |
4b804c85 | 2250 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2251 | |
4b804c85 RV |
2252 | struct cpumask __cpu_online_mask __read_mostly; |
2253 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2254 | |
4b804c85 RV |
2255 | struct cpumask __cpu_present_mask __read_mostly; |
2256 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2257 | |
4b804c85 RV |
2258 | struct cpumask __cpu_active_mask __read_mostly; |
2259 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2260 | |
3fa41520 RR |
2261 | void init_cpu_present(const struct cpumask *src) |
2262 | { | |
c4c54dd1 | 2263 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2264 | } |
2265 | ||
2266 | void init_cpu_possible(const struct cpumask *src) | |
2267 | { | |
c4c54dd1 | 2268 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2269 | } |
2270 | ||
2271 | void init_cpu_online(const struct cpumask *src) | |
2272 | { | |
c4c54dd1 | 2273 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2274 | } |
cff7d378 TG |
2275 | |
2276 | /* | |
2277 | * Activate the first processor. | |
2278 | */ | |
2279 | void __init boot_cpu_init(void) | |
2280 | { | |
2281 | int cpu = smp_processor_id(); | |
2282 | ||
2283 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2284 | set_cpu_online(cpu, true); | |
2285 | set_cpu_active(cpu, true); | |
2286 | set_cpu_present(cpu, true); | |
2287 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2288 | |
2289 | #ifdef CONFIG_SMP | |
2290 | __boot_cpu_id = cpu; | |
2291 | #endif | |
cff7d378 TG |
2292 | } |
2293 | ||
2294 | /* | |
2295 | * Must be called _AFTER_ setting up the per_cpu areas | |
2296 | */ | |
d403c57a | 2297 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2298 | { |
59b2bd3d | 2299 | #ifdef CONFIG_SMP |
c1f7608e | 2300 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->booted_once = true; |
59b2bd3d | 2301 | #endif |
c1f7608e | 2302 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; |
cff7d378 | 2303 | } |
658dad68 | 2304 | |
fee33a7d TH |
2305 | /* |
2306 | * These are used for a global "mitigations=" cmdline option for toggling | |
2307 | * optional CPU mitigations. | |
2308 | */ | |
2309 | enum cpu_mitigations { | |
2310 | CPU_MITIGATIONS_OFF, | |
2311 | CPU_MITIGATIONS_AUTO, | |
2312 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2313 | }; | |
2314 | ||
2315 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2316 | CPU_MITIGATIONS_AUTO; | |
658dad68 JP |
2317 | |
2318 | static int __init mitigations_parse_cmdline(char *arg) | |
2319 | { | |
2320 | if (!strcmp(arg, "off")) | |
2321 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2322 | else if (!strcmp(arg, "auto")) | |
2323 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2324 | else if (!strcmp(arg, "auto,nosmt")) | |
2325 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
88cae198 GU |
2326 | else |
2327 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2328 | arg); | |
658dad68 JP |
2329 | |
2330 | return 0; | |
2331 | } | |
2332 | early_param("mitigations", mitigations_parse_cmdline); | |
fee33a7d TH |
2333 | |
2334 | /* mitigations=off */ | |
2335 | bool cpu_mitigations_off(void) | |
2336 | { | |
2337 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2338 | } | |
2339 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2340 | ||
2341 | /* mitigations=auto,nosmt */ | |
2342 | bool cpu_mitigations_auto_nosmt(void) | |
2343 | { | |
2344 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2345 | } | |
2346 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |