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 | */ | |
bf2c59fc | 6 | #include <linux/sched/mm.h> |
1da177e4 LT |
7 | #include <linux/proc_fs.h> |
8 | #include <linux/smp.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/notifier.h> | |
3f07c014 | 11 | #include <linux/sched/signal.h> |
ef8bd77f | 12 | #include <linux/sched/hotplug.h> |
9ca12ac0 | 13 | #include <linux/sched/isolation.h> |
29930025 | 14 | #include <linux/sched/task.h> |
a74cfffb | 15 | #include <linux/sched/smt.h> |
1da177e4 LT |
16 | #include <linux/unistd.h> |
17 | #include <linux/cpu.h> | |
cb79295e AV |
18 | #include <linux/oom.h> |
19 | #include <linux/rcupdate.h> | |
9984de1a | 20 | #include <linux/export.h> |
e4cc2f87 | 21 | #include <linux/bug.h> |
1da177e4 LT |
22 | #include <linux/kthread.h> |
23 | #include <linux/stop_machine.h> | |
81615b62 | 24 | #include <linux/mutex.h> |
5a0e3ad6 | 25 | #include <linux/gfp.h> |
79cfbdfa | 26 | #include <linux/suspend.h> |
a19423b9 | 27 | #include <linux/lockdep.h> |
345527b1 | 28 | #include <linux/tick.h> |
a8994181 | 29 | #include <linux/irq.h> |
941154bd | 30 | #include <linux/nmi.h> |
4cb28ced | 31 | #include <linux/smpboot.h> |
e6d4989a | 32 | #include <linux/relay.h> |
6731d4f1 | 33 | #include <linux/slab.h> |
fc8dffd3 | 34 | #include <linux/percpu-rwsem.h> |
b22afcdf | 35 | #include <linux/cpuset.h> |
cff7d378 | 36 | |
bb3632c6 | 37 | #include <trace/events/power.h> |
cff7d378 TG |
38 | #define CREATE_TRACE_POINTS |
39 | #include <trace/events/cpuhp.h> | |
1da177e4 | 40 | |
38498a67 TG |
41 | #include "smpboot.h" |
42 | ||
cff7d378 | 43 | /** |
11bc021d | 44 | * struct cpuhp_cpu_state - Per cpu hotplug state storage |
cff7d378 TG |
45 | * @state: The current cpu state |
46 | * @target: The target state | |
11bc021d | 47 | * @fail: Current CPU hotplug callback state |
4cb28ced TG |
48 | * @thread: Pointer to the hotplug thread |
49 | * @should_run: Thread should execute | |
3b9d6da6 | 50 | * @rollback: Perform a rollback |
a724632c TG |
51 | * @single: Single callback invocation |
52 | * @bringup: Single callback bringup or teardown selector | |
11bc021d RD |
53 | * @cpu: CPU number |
54 | * @node: Remote CPU node; for multi-instance, do a | |
55 | * single entry callback for install/remove | |
56 | * @last: For multi-instance rollback, remember how far we got | |
a724632c | 57 | * @cb_state: The state for a single callback (install/uninstall) |
4cb28ced | 58 | * @result: Result of the operation |
5ebe7742 PZ |
59 | * @done_up: Signal completion to the issuer of the task for cpu-up |
60 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
61 | */ |
62 | struct cpuhp_cpu_state { | |
63 | enum cpuhp_state state; | |
64 | enum cpuhp_state target; | |
1db49484 | 65 | enum cpuhp_state fail; |
4cb28ced TG |
66 | #ifdef CONFIG_SMP |
67 | struct task_struct *thread; | |
68 | bool should_run; | |
3b9d6da6 | 69 | bool rollback; |
a724632c TG |
70 | bool single; |
71 | bool bringup; | |
2ea46c6f | 72 | int cpu; |
cf392d10 | 73 | struct hlist_node *node; |
4dddfb5f | 74 | struct hlist_node *last; |
4cb28ced | 75 | enum cpuhp_state cb_state; |
4cb28ced | 76 | int result; |
5ebe7742 PZ |
77 | struct completion done_up; |
78 | struct completion done_down; | |
4cb28ced | 79 | #endif |
cff7d378 TG |
80 | }; |
81 | ||
1db49484 PZ |
82 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
83 | .fail = CPUHP_INVALID, | |
84 | }; | |
cff7d378 | 85 | |
e797bda3 TG |
86 | #ifdef CONFIG_SMP |
87 | cpumask_t cpus_booted_once_mask; | |
88 | #endif | |
89 | ||
49dfe2a6 | 90 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
91 | static struct lockdep_map cpuhp_state_up_map = |
92 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
93 | static struct lockdep_map cpuhp_state_down_map = | |
94 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
95 | ||
96 | ||
76dc6c09 | 97 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
98 | { |
99 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
100 | } | |
101 | ||
76dc6c09 | 102 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
103 | { |
104 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
105 | } | |
106 | #else | |
107 | ||
76dc6c09 MM |
108 | static inline void cpuhp_lock_acquire(bool bringup) { } |
109 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 110 | |
49dfe2a6 TG |
111 | #endif |
112 | ||
cff7d378 | 113 | /** |
11bc021d | 114 | * struct cpuhp_step - Hotplug state machine step |
cff7d378 TG |
115 | * @name: Name of the step |
116 | * @startup: Startup function of the step | |
117 | * @teardown: Teardown function of the step | |
757c989b | 118 | * @cant_stop: Bringup/teardown can't be stopped at this step |
11bc021d | 119 | * @multi_instance: State has multiple instances which get added afterwards |
cff7d378 TG |
120 | */ |
121 | struct cpuhp_step { | |
cf392d10 TG |
122 | const char *name; |
123 | union { | |
3c1627e9 TG |
124 | int (*single)(unsigned int cpu); |
125 | int (*multi)(unsigned int cpu, | |
126 | struct hlist_node *node); | |
127 | } startup; | |
cf392d10 | 128 | union { |
3c1627e9 TG |
129 | int (*single)(unsigned int cpu); |
130 | int (*multi)(unsigned int cpu, | |
131 | struct hlist_node *node); | |
132 | } teardown; | |
11bc021d | 133 | /* private: */ |
cf392d10 | 134 | struct hlist_head list; |
11bc021d | 135 | /* public: */ |
cf392d10 TG |
136 | bool cant_stop; |
137 | bool multi_instance; | |
cff7d378 TG |
138 | }; |
139 | ||
98f8cdce | 140 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 141 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 142 | |
a724632c TG |
143 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
144 | { | |
17a2f1ce | 145 | return cpuhp_hp_states + state; |
a724632c TG |
146 | } |
147 | ||
453e4108 VD |
148 | static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step) |
149 | { | |
150 | return bringup ? !step->startup.single : !step->teardown.single; | |
151 | } | |
152 | ||
cff7d378 | 153 | /** |
11bc021d | 154 | * cpuhp_invoke_callback - Invoke the callbacks for a given state |
cff7d378 | 155 | * @cpu: The cpu for which the callback should be invoked |
96abb968 | 156 | * @state: The state to do callbacks for |
a724632c | 157 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
158 | * @node: For multi-instance, do a single entry callback for install/remove |
159 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 160 | * |
cf392d10 | 161 | * Called from cpu hotplug and from the state register machinery. |
11bc021d RD |
162 | * |
163 | * Return: %0 on success or a negative errno code | |
cff7d378 | 164 | */ |
a724632c | 165 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
166 | bool bringup, struct hlist_node *node, |
167 | struct hlist_node **lastp) | |
cff7d378 TG |
168 | { |
169 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 170 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
171 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
172 | int (*cb)(unsigned int cpu); | |
173 | int ret, cnt; | |
174 | ||
1db49484 PZ |
175 | if (st->fail == state) { |
176 | st->fail = CPUHP_INVALID; | |
1db49484 PZ |
177 | return -EAGAIN; |
178 | } | |
179 | ||
453e4108 VD |
180 | if (cpuhp_step_empty(bringup, step)) { |
181 | WARN_ON_ONCE(1); | |
182 | return 0; | |
183 | } | |
184 | ||
cf392d10 | 185 | if (!step->multi_instance) { |
96abb968 | 186 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 187 | cb = bringup ? step->startup.single : step->teardown.single; |
453e4108 | 188 | |
a724632c | 189 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 190 | ret = cb(cpu); |
a724632c | 191 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
192 | return ret; |
193 | } | |
3c1627e9 | 194 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
195 | |
196 | /* Single invocation for instance add/remove */ | |
197 | if (node) { | |
96abb968 | 198 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
199 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
200 | ret = cbm(cpu, node); | |
201 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
202 | return ret; | |
203 | } | |
204 | ||
205 | /* State transition. Invoke on all instances */ | |
206 | cnt = 0; | |
207 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
208 | if (lastp && node == *lastp) |
209 | break; | |
210 | ||
cf392d10 TG |
211 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
212 | ret = cbm(cpu, node); | |
213 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
214 | if (ret) { |
215 | if (!lastp) | |
216 | goto err; | |
217 | ||
218 | *lastp = node; | |
219 | return ret; | |
220 | } | |
cf392d10 TG |
221 | cnt++; |
222 | } | |
96abb968 PZ |
223 | if (lastp) |
224 | *lastp = NULL; | |
cf392d10 TG |
225 | return 0; |
226 | err: | |
227 | /* Rollback the instances if one failed */ | |
3c1627e9 | 228 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
229 | if (!cbm) |
230 | return ret; | |
231 | ||
232 | hlist_for_each(node, &step->list) { | |
233 | if (!cnt--) | |
234 | break; | |
724a8688 PZ |
235 | |
236 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
237 | ret = cbm(cpu, node); | |
238 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
239 | /* | |
240 | * Rollback must not fail, | |
241 | */ | |
242 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
243 | } |
244 | return ret; | |
245 | } | |
246 | ||
98a79d6a | 247 | #ifdef CONFIG_SMP |
fcb3029a AB |
248 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
249 | { | |
250 | /* | |
251 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
252 | * purposes as that state is handled explicitly in cpu_down. | |
253 | */ | |
254 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
255 | } | |
256 | ||
5ebe7742 PZ |
257 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
258 | { | |
259 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
260 | wait_for_completion(done); | |
261 | } | |
262 | ||
263 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
264 | { | |
265 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
266 | complete(done); | |
267 | } | |
268 | ||
269 | /* | |
270 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
271 | */ | |
272 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
273 | { | |
274 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
275 | } | |
276 | ||
b3199c02 | 277 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 278 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
279 | bool cpuhp_tasks_frozen; |
280 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 281 | |
79a6cdeb | 282 | /* |
93ae4f97 SB |
283 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
284 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
285 | */ |
286 | void cpu_maps_update_begin(void) | |
287 | { | |
288 | mutex_lock(&cpu_add_remove_lock); | |
289 | } | |
290 | ||
291 | void cpu_maps_update_done(void) | |
292 | { | |
293 | mutex_unlock(&cpu_add_remove_lock); | |
294 | } | |
1da177e4 | 295 | |
fc8dffd3 TG |
296 | /* |
297 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
298 | * Should always be manipulated under cpu_add_remove_lock |
299 | */ | |
300 | static int cpu_hotplug_disabled; | |
301 | ||
79a6cdeb LJ |
302 | #ifdef CONFIG_HOTPLUG_CPU |
303 | ||
fc8dffd3 | 304 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 305 | |
8f553c49 | 306 | void cpus_read_lock(void) |
a9d9baa1 | 307 | { |
fc8dffd3 | 308 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 309 | } |
8f553c49 | 310 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 311 | |
6f4ceee9 WL |
312 | int cpus_read_trylock(void) |
313 | { | |
314 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
315 | } | |
316 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
317 | ||
8f553c49 | 318 | void cpus_read_unlock(void) |
a9d9baa1 | 319 | { |
fc8dffd3 | 320 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 321 | } |
8f553c49 | 322 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 323 | |
8f553c49 | 324 | void cpus_write_lock(void) |
d221938c | 325 | { |
fc8dffd3 | 326 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 327 | } |
87af9e7f | 328 | |
8f553c49 | 329 | void cpus_write_unlock(void) |
d221938c | 330 | { |
fc8dffd3 | 331 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
332 | } |
333 | ||
fc8dffd3 | 334 | void lockdep_assert_cpus_held(void) |
d221938c | 335 | { |
ce48c457 VS |
336 | /* |
337 | * We can't have hotplug operations before userspace starts running, | |
338 | * and some init codepaths will knowingly not take the hotplug lock. | |
339 | * This is all valid, so mute lockdep until it makes sense to report | |
340 | * unheld locks. | |
341 | */ | |
342 | if (system_state < SYSTEM_RUNNING) | |
343 | return; | |
344 | ||
fc8dffd3 | 345 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 346 | } |
79a6cdeb | 347 | |
43759fe5 FW |
348 | #ifdef CONFIG_LOCKDEP |
349 | int lockdep_is_cpus_held(void) | |
350 | { | |
351 | return percpu_rwsem_is_held(&cpu_hotplug_lock); | |
352 | } | |
353 | #endif | |
354 | ||
cb92173d PZ |
355 | static void lockdep_acquire_cpus_lock(void) |
356 | { | |
1751060e | 357 | rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); |
cb92173d PZ |
358 | } |
359 | ||
360 | static void lockdep_release_cpus_lock(void) | |
361 | { | |
1751060e | 362 | rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_); |
cb92173d PZ |
363 | } |
364 | ||
16e53dbf SB |
365 | /* |
366 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
367 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
368 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
369 | * hotplug path before performing hotplug operations. So acquiring that lock | |
370 | * guarantees mutual exclusion from any currently running hotplug operations. | |
371 | */ | |
372 | void cpu_hotplug_disable(void) | |
373 | { | |
374 | cpu_maps_update_begin(); | |
89af7ba5 | 375 | cpu_hotplug_disabled++; |
16e53dbf SB |
376 | cpu_maps_update_done(); |
377 | } | |
32145c46 | 378 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 379 | |
01b41159 LW |
380 | static void __cpu_hotplug_enable(void) |
381 | { | |
382 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
383 | return; | |
384 | cpu_hotplug_disabled--; | |
385 | } | |
386 | ||
16e53dbf SB |
387 | void cpu_hotplug_enable(void) |
388 | { | |
389 | cpu_maps_update_begin(); | |
01b41159 | 390 | __cpu_hotplug_enable(); |
16e53dbf SB |
391 | cpu_maps_update_done(); |
392 | } | |
32145c46 | 393 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
394 | |
395 | #else | |
396 | ||
397 | static void lockdep_acquire_cpus_lock(void) | |
398 | { | |
399 | } | |
400 | ||
401 | static void lockdep_release_cpus_lock(void) | |
402 | { | |
403 | } | |
404 | ||
b9d10be7 | 405 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 406 | |
a74cfffb TG |
407 | /* |
408 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
409 | * should override this. | |
410 | */ | |
411 | void __weak arch_smt_update(void) { } | |
412 | ||
0cc3cd21 TG |
413 | #ifdef CONFIG_HOTPLUG_SMT |
414 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 415 | |
8e1b706b | 416 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 417 | { |
e1572f1d | 418 | if (!cpu_smt_possible()) |
8e1b706b JK |
419 | return; |
420 | ||
421 | if (force) { | |
0cc3cd21 TG |
422 | pr_info("SMT: Force disabled\n"); |
423 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 424 | } else { |
d0e7d144 | 425 | pr_info("SMT: disabled\n"); |
8e1b706b | 426 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 427 | } |
8e1b706b JK |
428 | } |
429 | ||
fee0aede TG |
430 | /* |
431 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 432 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
433 | */ |
434 | void __init cpu_smt_check_topology(void) | |
435 | { | |
b284909a | 436 | if (!topology_smt_supported()) |
bc2d8d26 TG |
437 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
438 | } | |
439 | ||
8e1b706b JK |
440 | static int __init smt_cmdline_disable(char *str) |
441 | { | |
442 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
443 | return 0; |
444 | } | |
445 | early_param("nosmt", smt_cmdline_disable); | |
446 | ||
447 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
448 | { | |
b284909a | 449 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
450 | return true; |
451 | ||
b284909a | 452 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
453 | return true; |
454 | ||
455 | /* | |
456 | * On x86 it's required to boot all logical CPUs at least once so | |
457 | * that the init code can get a chance to set CR4.MCE on each | |
182e073f | 458 | * CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any |
0cc3cd21 TG |
459 | * core will shutdown the machine. |
460 | */ | |
e797bda3 | 461 | return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); |
0cc3cd21 | 462 | } |
e1572f1d VK |
463 | |
464 | /* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ | |
465 | bool cpu_smt_possible(void) | |
466 | { | |
467 | return cpu_smt_control != CPU_SMT_FORCE_DISABLED && | |
468 | cpu_smt_control != CPU_SMT_NOT_SUPPORTED; | |
469 | } | |
470 | EXPORT_SYMBOL_GPL(cpu_smt_possible); | |
0cc3cd21 TG |
471 | #else |
472 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
473 | #endif | |
474 | ||
4dddfb5f PZ |
475 | static inline enum cpuhp_state |
476 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
477 | { | |
478 | enum cpuhp_state prev_state = st->state; | |
2ea46c6f | 479 | bool bringup = st->state < target; |
4dddfb5f PZ |
480 | |
481 | st->rollback = false; | |
482 | st->last = NULL; | |
483 | ||
484 | st->target = target; | |
485 | st->single = false; | |
2ea46c6f PZ |
486 | st->bringup = bringup; |
487 | if (cpu_dying(st->cpu) != !bringup) | |
488 | set_cpu_dying(st->cpu, !bringup); | |
4dddfb5f PZ |
489 | |
490 | return prev_state; | |
491 | } | |
492 | ||
493 | static inline void | |
494 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
495 | { | |
2ea46c6f PZ |
496 | bool bringup = !st->bringup; |
497 | ||
453e4108 VD |
498 | st->target = prev_state; |
499 | ||
500 | /* | |
501 | * Already rolling back. No need invert the bringup value or to change | |
502 | * the current state. | |
503 | */ | |
504 | if (st->rollback) | |
505 | return; | |
506 | ||
4dddfb5f PZ |
507 | st->rollback = true; |
508 | ||
509 | /* | |
510 | * If we have st->last we need to undo partial multi_instance of this | |
511 | * state first. Otherwise start undo at the previous state. | |
512 | */ | |
513 | if (!st->last) { | |
514 | if (st->bringup) | |
515 | st->state--; | |
516 | else | |
517 | st->state++; | |
518 | } | |
519 | ||
2ea46c6f PZ |
520 | st->bringup = bringup; |
521 | if (cpu_dying(st->cpu) != !bringup) | |
522 | set_cpu_dying(st->cpu, !bringup); | |
4dddfb5f PZ |
523 | } |
524 | ||
525 | /* Regular hotplug invocation of the AP hotplug thread */ | |
526 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
527 | { | |
528 | if (!st->single && st->state == st->target) | |
529 | return; | |
530 | ||
531 | st->result = 0; | |
532 | /* | |
533 | * Make sure the above stores are visible before should_run becomes | |
534 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
535 | */ | |
536 | smp_mb(); | |
537 | st->should_run = true; | |
538 | wake_up_process(st->thread); | |
5ebe7742 | 539 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
540 | } |
541 | ||
542 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
543 | { | |
544 | enum cpuhp_state prev_state; | |
545 | int ret; | |
546 | ||
547 | prev_state = cpuhp_set_state(st, target); | |
548 | __cpuhp_kick_ap(st); | |
549 | if ((ret = st->result)) { | |
550 | cpuhp_reset_state(st, prev_state); | |
551 | __cpuhp_kick_ap(st); | |
552 | } | |
553 | ||
554 | return ret; | |
555 | } | |
9cd4f1a4 | 556 | |
8df3e07e TG |
557 | static int bringup_wait_for_ap(unsigned int cpu) |
558 | { | |
559 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
560 | ||
9cd4f1a4 | 561 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 562 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
563 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
564 | return -ECANCELED; | |
9cd4f1a4 | 565 | |
45178ac0 | 566 | /* Unpark the hotplug thread of the target cpu */ |
9cd4f1a4 TG |
567 | kthread_unpark(st->thread); |
568 | ||
0cc3cd21 TG |
569 | /* |
570 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
571 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 572 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
573 | * cpu_smt_allowed() check will now return false if this is not the |
574 | * primary sibling. | |
575 | */ | |
576 | if (!cpu_smt_allowed(cpu)) | |
577 | return -ECANCELED; | |
578 | ||
4dddfb5f PZ |
579 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
580 | return 0; | |
581 | ||
582 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
583 | } |
584 | ||
ba997462 TG |
585 | static int bringup_cpu(unsigned int cpu) |
586 | { | |
587 | struct task_struct *idle = idle_thread_get(cpu); | |
588 | int ret; | |
589 | ||
aa877175 BO |
590 | /* |
591 | * Some architectures have to walk the irq descriptors to | |
592 | * setup the vector space for the cpu which comes online. | |
593 | * Prevent irq alloc/free across the bringup. | |
594 | */ | |
595 | irq_lock_sparse(); | |
596 | ||
ba997462 TG |
597 | /* Arch-specific enabling code. */ |
598 | ret = __cpu_up(cpu, idle); | |
aa877175 | 599 | irq_unlock_sparse(); |
530e9b76 | 600 | if (ret) |
ba997462 | 601 | return ret; |
9cd4f1a4 | 602 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
603 | } |
604 | ||
bf2c59fc PZ |
605 | static int finish_cpu(unsigned int cpu) |
606 | { | |
607 | struct task_struct *idle = idle_thread_get(cpu); | |
608 | struct mm_struct *mm = idle->active_mm; | |
609 | ||
610 | /* | |
611 | * idle_task_exit() will have switched to &init_mm, now | |
612 | * clean up any remaining active_mm state. | |
613 | */ | |
614 | if (mm != &init_mm) | |
615 | idle->active_mm = &init_mm; | |
616 | mmdrop(mm); | |
617 | return 0; | |
618 | } | |
619 | ||
2e1a3483 TG |
620 | /* |
621 | * Hotplug state machine related functions | |
622 | */ | |
2e1a3483 | 623 | |
453e4108 VD |
624 | /* |
625 | * Get the next state to run. Empty ones will be skipped. Returns true if a | |
626 | * state must be run. | |
627 | * | |
628 | * st->state will be modified ahead of time, to match state_to_run, as if it | |
629 | * has already ran. | |
630 | */ | |
631 | static bool cpuhp_next_state(bool bringup, | |
632 | enum cpuhp_state *state_to_run, | |
633 | struct cpuhp_cpu_state *st, | |
634 | enum cpuhp_state target) | |
2e1a3483 | 635 | { |
453e4108 VD |
636 | do { |
637 | if (bringup) { | |
638 | if (st->state >= target) | |
639 | return false; | |
640 | ||
641 | *state_to_run = ++st->state; | |
642 | } else { | |
643 | if (st->state <= target) | |
644 | return false; | |
645 | ||
646 | *state_to_run = st->state--; | |
647 | } | |
648 | ||
649 | if (!cpuhp_step_empty(bringup, cpuhp_get_step(*state_to_run))) | |
650 | break; | |
651 | } while (true); | |
652 | ||
653 | return true; | |
654 | } | |
655 | ||
656 | static int cpuhp_invoke_callback_range(bool bringup, | |
657 | unsigned int cpu, | |
658 | struct cpuhp_cpu_state *st, | |
659 | enum cpuhp_state target) | |
660 | { | |
661 | enum cpuhp_state state; | |
662 | int err = 0; | |
663 | ||
664 | while (cpuhp_next_state(bringup, &state, st, target)) { | |
665 | err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL); | |
666 | if (err) | |
667 | break; | |
668 | } | |
669 | ||
670 | return err; | |
2e1a3483 TG |
671 | } |
672 | ||
206b9235 TG |
673 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
674 | { | |
675 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
676 | return true; | |
677 | /* | |
678 | * When CPU hotplug is disabled, then taking the CPU down is not | |
679 | * possible because takedown_cpu() and the architecture and | |
680 | * subsystem specific mechanisms are not available. So the CPU | |
681 | * which would be completely unplugged again needs to stay around | |
682 | * in the current state. | |
683 | */ | |
684 | return st->state <= CPUHP_BRINGUP_CPU; | |
685 | } | |
686 | ||
2e1a3483 | 687 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 688 | enum cpuhp_state target) |
2e1a3483 TG |
689 | { |
690 | enum cpuhp_state prev_state = st->state; | |
691 | int ret = 0; | |
692 | ||
453e4108 VD |
693 | ret = cpuhp_invoke_callback_range(true, cpu, st, target); |
694 | if (ret) { | |
ebca71a8 DZ |
695 | pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n", |
696 | ret, cpu, cpuhp_get_step(st->state)->name, | |
697 | st->state); | |
698 | ||
453e4108 VD |
699 | cpuhp_reset_state(st, prev_state); |
700 | if (can_rollback_cpu(st)) | |
701 | WARN_ON(cpuhp_invoke_callback_range(false, cpu, st, | |
702 | prev_state)); | |
2e1a3483 TG |
703 | } |
704 | return ret; | |
705 | } | |
706 | ||
4cb28ced TG |
707 | /* |
708 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
709 | */ | |
710 | static void cpuhp_create(unsigned int cpu) | |
711 | { | |
712 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
713 | ||
5ebe7742 PZ |
714 | init_completion(&st->done_up); |
715 | init_completion(&st->done_down); | |
2ea46c6f | 716 | st->cpu = cpu; |
4cb28ced TG |
717 | } |
718 | ||
719 | static int cpuhp_should_run(unsigned int cpu) | |
720 | { | |
721 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
722 | ||
723 | return st->should_run; | |
724 | } | |
725 | ||
4cb28ced TG |
726 | /* |
727 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
728 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
729 | * |
730 | * Each invocation of this function by the smpboot thread does a single AP | |
731 | * state callback. | |
732 | * | |
733 | * It has 3 modes of operation: | |
734 | * - single: runs st->cb_state | |
735 | * - up: runs ++st->state, while st->state < st->target | |
736 | * - down: runs st->state--, while st->state > st->target | |
737 | * | |
738 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
739 | */ |
740 | static void cpuhp_thread_fun(unsigned int cpu) | |
741 | { | |
742 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
743 | bool bringup = st->bringup; |
744 | enum cpuhp_state state; | |
4cb28ced | 745 | |
f8b7530a NU |
746 | if (WARN_ON_ONCE(!st->should_run)) |
747 | return; | |
748 | ||
4cb28ced | 749 | /* |
4dddfb5f PZ |
750 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
751 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
752 | */ |
753 | smp_mb(); | |
4cb28ced | 754 | |
cb92173d PZ |
755 | /* |
756 | * The BP holds the hotplug lock, but we're now running on the AP, | |
757 | * ensure that anybody asserting the lock is held, will actually find | |
758 | * it so. | |
759 | */ | |
760 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 761 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 762 | |
a724632c | 763 | if (st->single) { |
4dddfb5f PZ |
764 | state = st->cb_state; |
765 | st->should_run = false; | |
766 | } else { | |
453e4108 VD |
767 | st->should_run = cpuhp_next_state(bringup, &state, st, st->target); |
768 | if (!st->should_run) | |
769 | goto end; | |
4dddfb5f PZ |
770 | } |
771 | ||
772 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
773 | ||
4dddfb5f PZ |
774 | if (cpuhp_is_atomic_state(state)) { |
775 | local_irq_disable(); | |
776 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
777 | local_irq_enable(); | |
3b9d6da6 | 778 | |
4dddfb5f PZ |
779 | /* |
780 | * STARTING/DYING must not fail! | |
781 | */ | |
782 | WARN_ON_ONCE(st->result); | |
4cb28ced | 783 | } else { |
4dddfb5f PZ |
784 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
785 | } | |
786 | ||
787 | if (st->result) { | |
788 | /* | |
789 | * If we fail on a rollback, we're up a creek without no | |
790 | * paddle, no way forward, no way back. We loose, thanks for | |
791 | * playing. | |
792 | */ | |
793 | WARN_ON_ONCE(st->rollback); | |
794 | st->should_run = false; | |
4cb28ced | 795 | } |
4dddfb5f | 796 | |
453e4108 | 797 | end: |
5f4b55e1 | 798 | cpuhp_lock_release(bringup); |
cb92173d | 799 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
800 | |
801 | if (!st->should_run) | |
5ebe7742 | 802 | complete_ap_thread(st, bringup); |
4cb28ced TG |
803 | } |
804 | ||
805 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 806 | static int |
cf392d10 TG |
807 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
808 | struct hlist_node *node) | |
4cb28ced TG |
809 | { |
810 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 811 | int ret; |
4cb28ced TG |
812 | |
813 | if (!cpu_online(cpu)) | |
814 | return 0; | |
815 | ||
5f4b55e1 PZ |
816 | cpuhp_lock_acquire(false); |
817 | cpuhp_lock_release(false); | |
818 | ||
819 | cpuhp_lock_acquire(true); | |
820 | cpuhp_lock_release(true); | |
49dfe2a6 | 821 | |
6a4e2451 TG |
822 | /* |
823 | * If we are up and running, use the hotplug thread. For early calls | |
824 | * we invoke the thread function directly. | |
825 | */ | |
826 | if (!st->thread) | |
96abb968 | 827 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 828 | |
4dddfb5f PZ |
829 | st->rollback = false; |
830 | st->last = NULL; | |
831 | ||
832 | st->node = node; | |
833 | st->bringup = bringup; | |
4cb28ced | 834 | st->cb_state = state; |
a724632c | 835 | st->single = true; |
a724632c | 836 | |
4dddfb5f | 837 | __cpuhp_kick_ap(st); |
4cb28ced | 838 | |
4cb28ced | 839 | /* |
4dddfb5f | 840 | * If we failed and did a partial, do a rollback. |
4cb28ced | 841 | */ |
4dddfb5f PZ |
842 | if ((ret = st->result) && st->last) { |
843 | st->rollback = true; | |
844 | st->bringup = !bringup; | |
845 | ||
846 | __cpuhp_kick_ap(st); | |
847 | } | |
848 | ||
1f7c70d6 TG |
849 | /* |
850 | * Clean up the leftovers so the next hotplug operation wont use stale | |
851 | * data. | |
852 | */ | |
853 | st->node = st->last = NULL; | |
4dddfb5f | 854 | return ret; |
1cf4f629 TG |
855 | } |
856 | ||
857 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
858 | { | |
859 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
860 | enum cpuhp_state prev_state = st->state; |
861 | int ret; | |
1cf4f629 | 862 | |
5f4b55e1 PZ |
863 | cpuhp_lock_acquire(false); |
864 | cpuhp_lock_release(false); | |
865 | ||
866 | cpuhp_lock_acquire(true); | |
867 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
868 | |
869 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
870 | ret = cpuhp_kick_ap(st, st->target); | |
871 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
872 | ||
873 | return ret; | |
4cb28ced TG |
874 | } |
875 | ||
876 | static struct smp_hotplug_thread cpuhp_threads = { | |
877 | .store = &cpuhp_state.thread, | |
878 | .create = &cpuhp_create, | |
879 | .thread_should_run = cpuhp_should_run, | |
880 | .thread_fn = cpuhp_thread_fun, | |
881 | .thread_comm = "cpuhp/%u", | |
882 | .selfparking = true, | |
883 | }; | |
884 | ||
885 | void __init cpuhp_threads_init(void) | |
886 | { | |
887 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
888 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
889 | } | |
890 | ||
b22afcdf TG |
891 | /* |
892 | * | |
893 | * Serialize hotplug trainwrecks outside of the cpu_hotplug_lock | |
894 | * protected region. | |
895 | * | |
896 | * The operation is still serialized against concurrent CPU hotplug via | |
897 | * cpu_add_remove_lock, i.e. CPU map protection. But it is _not_ | |
898 | * serialized against other hotplug related activity like adding or | |
899 | * removing of state callbacks and state instances, which invoke either the | |
900 | * startup or the teardown callback of the affected state. | |
901 | * | |
902 | * This is required for subsystems which are unfixable vs. CPU hotplug and | |
903 | * evade lock inversion problems by scheduling work which has to be | |
904 | * completed _before_ cpu_up()/_cpu_down() returns. | |
905 | * | |
906 | * Don't even think about adding anything to this for any new code or even | |
907 | * drivers. It's only purpose is to keep existing lock order trainwrecks | |
908 | * working. | |
909 | * | |
910 | * For cpu_down() there might be valid reasons to finish cleanups which are | |
911 | * not required to be done under cpu_hotplug_lock, but that's a different | |
912 | * story and would be not invoked via this. | |
913 | */ | |
914 | static void cpu_up_down_serialize_trainwrecks(bool tasks_frozen) | |
915 | { | |
916 | /* | |
917 | * cpusets delegate hotplug operations to a worker to "solve" the | |
918 | * lock order problems. Wait for the worker, but only if tasks are | |
919 | * _not_ frozen (suspend, hibernate) as that would wait forever. | |
920 | * | |
921 | * The wait is required because otherwise the hotplug operation | |
922 | * returns with inconsistent state, which could even be observed in | |
923 | * user space when a new CPU is brought up. The CPU plug uevent | |
924 | * would be delivered and user space reacting on it would fail to | |
925 | * move tasks to the newly plugged CPU up to the point where the | |
926 | * work has finished because up to that point the newly plugged CPU | |
927 | * is not assignable in cpusets/cgroups. On unplug that's not | |
928 | * necessarily a visible issue, but it is still inconsistent state, | |
929 | * which is the real problem which needs to be "fixed". This can't | |
930 | * prevent the transient state between scheduling the work and | |
931 | * returning from waiting for it. | |
932 | */ | |
933 | if (!tasks_frozen) | |
934 | cpuset_wait_for_hotplug(); | |
935 | } | |
936 | ||
777c6e0d | 937 | #ifdef CONFIG_HOTPLUG_CPU |
8ff00399 NP |
938 | #ifndef arch_clear_mm_cpumask_cpu |
939 | #define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm)) | |
940 | #endif | |
941 | ||
e4cc2f87 AV |
942 | /** |
943 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
944 | * @cpu: a CPU id | |
945 | * | |
946 | * This function walks all processes, finds a valid mm struct for each one and | |
947 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
948 | * trivial, there are various non-obvious corner cases, which this function | |
949 | * tries to solve in a safe manner. | |
950 | * | |
951 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
952 | * be called only for an already offlined CPU. | |
953 | */ | |
cb79295e AV |
954 | void clear_tasks_mm_cpumask(int cpu) |
955 | { | |
956 | struct task_struct *p; | |
957 | ||
958 | /* | |
959 | * This function is called after the cpu is taken down and marked | |
960 | * offline, so its not like new tasks will ever get this cpu set in | |
961 | * their mm mask. -- Peter Zijlstra | |
962 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
963 | * full-fledged tasklist_lock. | |
964 | */ | |
e4cc2f87 | 965 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
966 | rcu_read_lock(); |
967 | for_each_process(p) { | |
968 | struct task_struct *t; | |
969 | ||
e4cc2f87 AV |
970 | /* |
971 | * Main thread might exit, but other threads may still have | |
972 | * a valid mm. Find one. | |
973 | */ | |
cb79295e AV |
974 | t = find_lock_task_mm(p); |
975 | if (!t) | |
976 | continue; | |
8ff00399 | 977 | arch_clear_mm_cpumask_cpu(cpu, t->mm); |
cb79295e AV |
978 | task_unlock(t); |
979 | } | |
980 | rcu_read_unlock(); | |
981 | } | |
982 | ||
1da177e4 | 983 | /* Take this CPU down. */ |
71cf5aee | 984 | static int take_cpu_down(void *_param) |
1da177e4 | 985 | { |
4baa0afc TG |
986 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
987 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 988 | int err, cpu = smp_processor_id(); |
724a8688 | 989 | int ret; |
1da177e4 | 990 | |
1da177e4 LT |
991 | /* Ensure this CPU doesn't handle any more interrupts. */ |
992 | err = __cpu_disable(); | |
993 | if (err < 0) | |
f3705136 | 994 | return err; |
1da177e4 | 995 | |
a724632c | 996 | /* |
453e4108 VD |
997 | * Must be called from CPUHP_TEARDOWN_CPU, which means, as we are going |
998 | * down, that the current state is CPUHP_TEARDOWN_CPU - 1. | |
a724632c | 999 | */ |
453e4108 VD |
1000 | WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1)); |
1001 | ||
4baa0afc | 1002 | /* Invoke the former CPU_DYING callbacks */ |
453e4108 VD |
1003 | ret = cpuhp_invoke_callback_range(false, cpu, st, target); |
1004 | ||
1005 | /* | |
1006 | * DYING must not fail! | |
1007 | */ | |
1008 | WARN_ON_ONCE(ret); | |
4baa0afc | 1009 | |
52c063d1 TG |
1010 | /* Give up timekeeping duties */ |
1011 | tick_handover_do_timer(); | |
1b72d432 TG |
1012 | /* Remove CPU from timer broadcasting */ |
1013 | tick_offline_cpu(cpu); | |
14e568e7 | 1014 | /* Park the stopper thread */ |
090e77c3 | 1015 | stop_machine_park(cpu); |
f3705136 | 1016 | return 0; |
1da177e4 LT |
1017 | } |
1018 | ||
98458172 | 1019 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 1020 | { |
e69aab13 | 1021 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 1022 | int err; |
1da177e4 | 1023 | |
2a58c527 | 1024 | /* Park the smpboot threads */ |
13070833 | 1025 | kthread_park(st->thread); |
1cf4f629 | 1026 | |
6acce3ef | 1027 | /* |
a8994181 TG |
1028 | * Prevent irq alloc/free while the dying cpu reorganizes the |
1029 | * interrupt affinities. | |
6acce3ef | 1030 | */ |
a8994181 | 1031 | irq_lock_sparse(); |
6acce3ef | 1032 | |
a8994181 TG |
1033 | /* |
1034 | * So now all preempt/rcu users must observe !cpu_active(). | |
1035 | */ | |
210e2133 | 1036 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 1037 | if (err) { |
3b9d6da6 | 1038 | /* CPU refused to die */ |
a8994181 | 1039 | irq_unlock_sparse(); |
3b9d6da6 | 1040 | /* Unpark the hotplug thread so we can rollback there */ |
13070833 | 1041 | kthread_unpark(st->thread); |
98458172 | 1042 | return err; |
8fa1d7d3 | 1043 | } |
04321587 | 1044 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 1045 | |
48c5ccae | 1046 | /* |
5b1ead68 BJ |
1047 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
1048 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 1049 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
1050 | * |
1051 | * Wait for the stop thread to go away. | |
48c5ccae | 1052 | */ |
5ebe7742 | 1053 | wait_for_ap_thread(st, false); |
e69aab13 | 1054 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 1055 | |
a8994181 TG |
1056 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
1057 | irq_unlock_sparse(); | |
1058 | ||
345527b1 | 1059 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
1060 | /* This actually kills the CPU. */ |
1061 | __cpu_die(cpu); | |
1062 | ||
a49b116d | 1063 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 1064 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
1065 | return 0; |
1066 | } | |
1da177e4 | 1067 | |
71f87b2f TG |
1068 | static void cpuhp_complete_idle_dead(void *arg) |
1069 | { | |
1070 | struct cpuhp_cpu_state *st = arg; | |
1071 | ||
5ebe7742 | 1072 | complete_ap_thread(st, false); |
71f87b2f TG |
1073 | } |
1074 | ||
e69aab13 TG |
1075 | void cpuhp_report_idle_dead(void) |
1076 | { | |
1077 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
1078 | ||
1079 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 1080 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
1081 | st->state = CPUHP_AP_IDLE_DEAD; |
1082 | /* | |
1083 | * We cannot call complete after rcu_report_dead() so we delegate it | |
1084 | * to an online cpu. | |
1085 | */ | |
1086 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
1087 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
1088 | } |
1089 | ||
4dddfb5f PZ |
1090 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
1091 | enum cpuhp_state target) | |
1092 | { | |
1093 | enum cpuhp_state prev_state = st->state; | |
1094 | int ret = 0; | |
1095 | ||
453e4108 VD |
1096 | ret = cpuhp_invoke_callback_range(false, cpu, st, target); |
1097 | if (ret) { | |
ebca71a8 DZ |
1098 | pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n", |
1099 | ret, cpu, cpuhp_get_step(st->state)->name, | |
1100 | st->state); | |
453e4108 VD |
1101 | |
1102 | cpuhp_reset_state(st, prev_state); | |
1103 | ||
1104 | if (st->state < prev_state) | |
1105 | WARN_ON(cpuhp_invoke_callback_range(true, cpu, st, | |
1106 | prev_state)); | |
4dddfb5f | 1107 | } |
453e4108 | 1108 | |
4dddfb5f PZ |
1109 | return ret; |
1110 | } | |
cff7d378 | 1111 | |
98458172 | 1112 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
1113 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
1114 | enum cpuhp_state target) | |
98458172 | 1115 | { |
cff7d378 TG |
1116 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
1117 | int prev_state, ret = 0; | |
98458172 TG |
1118 | |
1119 | if (num_online_cpus() == 1) | |
1120 | return -EBUSY; | |
1121 | ||
757c989b | 1122 | if (!cpu_present(cpu)) |
98458172 TG |
1123 | return -EINVAL; |
1124 | ||
8f553c49 | 1125 | cpus_write_lock(); |
98458172 TG |
1126 | |
1127 | cpuhp_tasks_frozen = tasks_frozen; | |
1128 | ||
4dddfb5f | 1129 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
1130 | /* |
1131 | * If the current CPU state is in the range of the AP hotplug thread, | |
1132 | * then we need to kick the thread. | |
1133 | */ | |
8df3e07e | 1134 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 1135 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
1136 | ret = cpuhp_kick_ap_work(cpu); |
1137 | /* | |
1138 | * The AP side has done the error rollback already. Just | |
1139 | * return the error code.. | |
1140 | */ | |
1141 | if (ret) | |
1142 | goto out; | |
1143 | ||
1144 | /* | |
1145 | * We might have stopped still in the range of the AP hotplug | |
1146 | * thread. Nothing to do anymore. | |
1147 | */ | |
8df3e07e | 1148 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1149 | goto out; |
4dddfb5f PZ |
1150 | |
1151 | st->target = target; | |
1cf4f629 TG |
1152 | } |
1153 | /* | |
8df3e07e | 1154 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1155 | * to do the further cleanups. |
1156 | */ | |
a724632c | 1157 | ret = cpuhp_down_callbacks(cpu, st, target); |
62f25069 VD |
1158 | if (ret && st->state < prev_state) { |
1159 | if (st->state == CPUHP_TEARDOWN_CPU) { | |
1160 | cpuhp_reset_state(st, prev_state); | |
1161 | __cpuhp_kick_ap(st); | |
1162 | } else { | |
1163 | WARN(1, "DEAD callback error for CPU%d", cpu); | |
1164 | } | |
3b9d6da6 | 1165 | } |
98458172 | 1166 | |
1cf4f629 | 1167 | out: |
8f553c49 | 1168 | cpus_write_unlock(); |
941154bd TG |
1169 | /* |
1170 | * Do post unplug cleanup. This is still protected against | |
1171 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1172 | */ | |
1173 | lockup_detector_cleanup(); | |
a74cfffb | 1174 | arch_smt_update(); |
b22afcdf | 1175 | cpu_up_down_serialize_trainwrecks(tasks_frozen); |
cff7d378 | 1176 | return ret; |
e3920fb4 RW |
1177 | } |
1178 | ||
cc1fe215 TG |
1179 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1180 | { | |
1181 | if (cpu_hotplug_disabled) | |
1182 | return -EBUSY; | |
1183 | return _cpu_down(cpu, 0, target); | |
1184 | } | |
1185 | ||
33c3736e | 1186 | static int cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1187 | { |
9ea09af3 | 1188 | int err; |
e3920fb4 | 1189 | |
d221938c | 1190 | cpu_maps_update_begin(); |
cc1fe215 | 1191 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1192 | cpu_maps_update_done(); |
1da177e4 LT |
1193 | return err; |
1194 | } | |
4dddfb5f | 1195 | |
33c3736e QY |
1196 | /** |
1197 | * cpu_device_down - Bring down a cpu device | |
1198 | * @dev: Pointer to the cpu device to offline | |
1199 | * | |
1200 | * This function is meant to be used by device core cpu subsystem only. | |
1201 | * | |
1202 | * Other subsystems should use remove_cpu() instead. | |
11bc021d RD |
1203 | * |
1204 | * Return: %0 on success or a negative errno code | |
33c3736e QY |
1205 | */ |
1206 | int cpu_device_down(struct device *dev) | |
af1f4045 | 1207 | { |
33c3736e | 1208 | return cpu_down(dev->id, CPUHP_OFFLINE); |
af1f4045 | 1209 | } |
4dddfb5f | 1210 | |
93ef1429 QY |
1211 | int remove_cpu(unsigned int cpu) |
1212 | { | |
1213 | int ret; | |
1214 | ||
1215 | lock_device_hotplug(); | |
1216 | ret = device_offline(get_cpu_device(cpu)); | |
1217 | unlock_device_hotplug(); | |
1218 | ||
1219 | return ret; | |
1220 | } | |
1221 | EXPORT_SYMBOL_GPL(remove_cpu); | |
1222 | ||
0441a559 QY |
1223 | void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) |
1224 | { | |
1225 | unsigned int cpu; | |
1226 | int error; | |
1227 | ||
1228 | cpu_maps_update_begin(); | |
1229 | ||
1230 | /* | |
1231 | * Make certain the cpu I'm about to reboot on is online. | |
1232 | * | |
1233 | * This is inline to what migrate_to_reboot_cpu() already do. | |
1234 | */ | |
1235 | if (!cpu_online(primary_cpu)) | |
1236 | primary_cpu = cpumask_first(cpu_online_mask); | |
1237 | ||
1238 | for_each_online_cpu(cpu) { | |
1239 | if (cpu == primary_cpu) | |
1240 | continue; | |
1241 | ||
1242 | error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
1243 | if (error) { | |
1244 | pr_err("Failed to offline CPU%d - error=%d", | |
1245 | cpu, error); | |
1246 | break; | |
1247 | } | |
1248 | } | |
1249 | ||
1250 | /* | |
1251 | * Ensure all but the reboot CPU are offline. | |
1252 | */ | |
1253 | BUG_ON(num_online_cpus() > 1); | |
1254 | ||
1255 | /* | |
1256 | * Make sure the CPUs won't be enabled by someone else after this | |
1257 | * point. Kexec will reboot to a new kernel shortly resetting | |
1258 | * everything along the way. | |
1259 | */ | |
1260 | cpu_hotplug_disabled++; | |
1261 | ||
1262 | cpu_maps_update_done(); | |
af1f4045 | 1263 | } |
4dddfb5f PZ |
1264 | |
1265 | #else | |
1266 | #define takedown_cpu NULL | |
1da177e4 LT |
1267 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1268 | ||
4baa0afc | 1269 | /** |
ee1e714b | 1270 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1271 | * @cpu: cpu that just started |
1272 | * | |
4baa0afc TG |
1273 | * It must be called by the arch code on the new cpu, before the new cpu |
1274 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1275 | */ | |
1276 | void notify_cpu_starting(unsigned int cpu) | |
1277 | { | |
1278 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1279 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1280 | int ret; |
4baa0afc | 1281 | |
0c6d4576 | 1282 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1283 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
453e4108 VD |
1284 | ret = cpuhp_invoke_callback_range(true, cpu, st, target); |
1285 | ||
1286 | /* | |
1287 | * STARTING must not fail! | |
1288 | */ | |
1289 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1290 | } |
1291 | ||
949338e3 | 1292 | /* |
9cd4f1a4 | 1293 | * Called from the idle task. Wake up the controlling task which brings the |
45178ac0 PZ |
1294 | * hotplug thread of the upcoming CPU up and then delegates the rest of the |
1295 | * online bringup to the hotplug thread. | |
949338e3 | 1296 | */ |
8df3e07e | 1297 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1298 | { |
8df3e07e | 1299 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1300 | |
1301 | /* Happens for the boot cpu */ | |
1302 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1303 | return; | |
1304 | ||
45178ac0 PZ |
1305 | /* |
1306 | * Unpart the stopper thread before we start the idle loop (and start | |
1307 | * scheduling); this ensures the stopper task is always available. | |
1308 | */ | |
1309 | stop_machine_unpark(smp_processor_id()); | |
1310 | ||
8df3e07e | 1311 | st->state = CPUHP_AP_ONLINE_IDLE; |
5ebe7742 | 1312 | complete_ap_thread(st, true); |
949338e3 TG |
1313 | } |
1314 | ||
e3920fb4 | 1315 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1316 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1317 | { |
cff7d378 | 1318 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1319 | struct task_struct *idle; |
2e1a3483 | 1320 | int ret = 0; |
1da177e4 | 1321 | |
8f553c49 | 1322 | cpus_write_lock(); |
38498a67 | 1323 | |
757c989b | 1324 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1325 | ret = -EINVAL; |
1326 | goto out; | |
1327 | } | |
1328 | ||
757c989b | 1329 | /* |
33c3736e QY |
1330 | * The caller of cpu_up() might have raced with another |
1331 | * caller. Nothing to do. | |
757c989b TG |
1332 | */ |
1333 | if (st->state >= target) | |
38498a67 | 1334 | goto out; |
757c989b TG |
1335 | |
1336 | if (st->state == CPUHP_OFFLINE) { | |
1337 | /* Let it fail before we try to bring the cpu up */ | |
1338 | idle = idle_thread_get(cpu); | |
1339 | if (IS_ERR(idle)) { | |
1340 | ret = PTR_ERR(idle); | |
1341 | goto out; | |
1342 | } | |
3bb5d2ee | 1343 | } |
38498a67 | 1344 | |
ba997462 TG |
1345 | cpuhp_tasks_frozen = tasks_frozen; |
1346 | ||
4dddfb5f | 1347 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1348 | /* |
1349 | * If the current CPU state is in the range of the AP hotplug thread, | |
1350 | * then we need to kick the thread once more. | |
1351 | */ | |
8df3e07e | 1352 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1353 | ret = cpuhp_kick_ap_work(cpu); |
1354 | /* | |
1355 | * The AP side has done the error rollback already. Just | |
1356 | * return the error code.. | |
1357 | */ | |
1358 | if (ret) | |
1359 | goto out; | |
1360 | } | |
1361 | ||
1362 | /* | |
1363 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1364 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1365 | * responsible for bringing it up to the target state. |
1366 | */ | |
8df3e07e | 1367 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1368 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1369 | out: |
8f553c49 | 1370 | cpus_write_unlock(); |
a74cfffb | 1371 | arch_smt_update(); |
b22afcdf | 1372 | cpu_up_down_serialize_trainwrecks(tasks_frozen); |
e3920fb4 RW |
1373 | return ret; |
1374 | } | |
1375 | ||
33c3736e | 1376 | static int cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1377 | { |
1378 | int err = 0; | |
cf23422b | 1379 | |
e0b582ec | 1380 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1381 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1382 | cpu); | |
87d5e023 | 1383 | #if defined(CONFIG_IA64) |
84117da5 | 1384 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1385 | #endif |
1386 | return -EINVAL; | |
1387 | } | |
e3920fb4 | 1388 | |
01b0f197 TK |
1389 | err = try_online_node(cpu_to_node(cpu)); |
1390 | if (err) | |
1391 | return err; | |
cf23422b | 1392 | |
d221938c | 1393 | cpu_maps_update_begin(); |
e761b772 MK |
1394 | |
1395 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1396 | err = -EBUSY; |
e761b772 MK |
1397 | goto out; |
1398 | } | |
05736e4a TG |
1399 | if (!cpu_smt_allowed(cpu)) { |
1400 | err = -EPERM; | |
1401 | goto out; | |
1402 | } | |
e761b772 | 1403 | |
af1f4045 | 1404 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1405 | out: |
d221938c | 1406 | cpu_maps_update_done(); |
e3920fb4 RW |
1407 | return err; |
1408 | } | |
af1f4045 | 1409 | |
33c3736e QY |
1410 | /** |
1411 | * cpu_device_up - Bring up a cpu device | |
1412 | * @dev: Pointer to the cpu device to online | |
1413 | * | |
1414 | * This function is meant to be used by device core cpu subsystem only. | |
1415 | * | |
1416 | * Other subsystems should use add_cpu() instead. | |
11bc021d RD |
1417 | * |
1418 | * Return: %0 on success or a negative errno code | |
33c3736e QY |
1419 | */ |
1420 | int cpu_device_up(struct device *dev) | |
af1f4045 | 1421 | { |
33c3736e | 1422 | return cpu_up(dev->id, CPUHP_ONLINE); |
af1f4045 | 1423 | } |
e3920fb4 | 1424 | |
93ef1429 QY |
1425 | int add_cpu(unsigned int cpu) |
1426 | { | |
1427 | int ret; | |
1428 | ||
1429 | lock_device_hotplug(); | |
1430 | ret = device_online(get_cpu_device(cpu)); | |
1431 | unlock_device_hotplug(); | |
1432 | ||
1433 | return ret; | |
1434 | } | |
1435 | EXPORT_SYMBOL_GPL(add_cpu); | |
1436 | ||
d720f986 QY |
1437 | /** |
1438 | * bringup_hibernate_cpu - Bring up the CPU that we hibernated on | |
1439 | * @sleep_cpu: The cpu we hibernated on and should be brought up. | |
1440 | * | |
1441 | * On some architectures like arm64, we can hibernate on any CPU, but on | |
1442 | * wake up the CPU we hibernated on might be offline as a side effect of | |
1443 | * using maxcpus= for example. | |
11bc021d RD |
1444 | * |
1445 | * Return: %0 on success or a negative errno code | |
d720f986 QY |
1446 | */ |
1447 | int bringup_hibernate_cpu(unsigned int sleep_cpu) | |
af1f4045 | 1448 | { |
d720f986 QY |
1449 | int ret; |
1450 | ||
1451 | if (!cpu_online(sleep_cpu)) { | |
1452 | pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); | |
33c3736e | 1453 | ret = cpu_up(sleep_cpu, CPUHP_ONLINE); |
d720f986 QY |
1454 | if (ret) { |
1455 | pr_err("Failed to bring hibernate-CPU up!\n"); | |
1456 | return ret; | |
1457 | } | |
1458 | } | |
1459 | return 0; | |
1460 | } | |
1461 | ||
b99a2659 QY |
1462 | void bringup_nonboot_cpus(unsigned int setup_max_cpus) |
1463 | { | |
1464 | unsigned int cpu; | |
1465 | ||
1466 | for_each_present_cpu(cpu) { | |
1467 | if (num_online_cpus() >= setup_max_cpus) | |
1468 | break; | |
1469 | if (!cpu_online(cpu)) | |
33c3736e | 1470 | cpu_up(cpu, CPUHP_ONLINE); |
b99a2659 | 1471 | } |
af1f4045 | 1472 | } |
e3920fb4 | 1473 | |
f3de4be9 | 1474 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1475 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1476 | |
fb7fb84a | 1477 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1478 | { |
d391e552 | 1479 | int cpu, error = 0; |
e3920fb4 | 1480 | |
d221938c | 1481 | cpu_maps_update_begin(); |
9ca12ac0 | 1482 | if (primary == -1) { |
d391e552 | 1483 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1484 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1485 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1486 | } else { | |
1487 | if (!cpu_online(primary)) | |
1488 | primary = cpumask_first(cpu_online_mask); | |
1489 | } | |
1490 | ||
9ee349ad XF |
1491 | /* |
1492 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1493 | * with the userspace trying to use the CPU hotplug at the same time |
1494 | */ | |
e0b582ec | 1495 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1496 | |
84117da5 | 1497 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1498 | for_each_online_cpu(cpu) { |
d391e552 | 1499 | if (cpu == primary) |
e3920fb4 | 1500 | continue; |
a66d955e | 1501 | |
fb7fb84a | 1502 | if (pm_wakeup_pending()) { |
a66d955e PK |
1503 | pr_info("Wakeup pending. Abort CPU freeze\n"); |
1504 | error = -EBUSY; | |
1505 | break; | |
1506 | } | |
1507 | ||
bb3632c6 | 1508 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1509 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1510 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1511 | if (!error) |
e0b582ec | 1512 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1513 | else { |
84117da5 | 1514 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1515 | break; |
1516 | } | |
1517 | } | |
86886e55 | 1518 | |
89af7ba5 | 1519 | if (!error) |
e3920fb4 | 1520 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1521 | else |
84117da5 | 1522 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1523 | |
1524 | /* | |
1525 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
56555855 QY |
1526 | * this even in case of failure as all freeze_secondary_cpus() users are |
1527 | * supposed to do thaw_secondary_cpus() on the failure path. | |
89af7ba5 VK |
1528 | */ |
1529 | cpu_hotplug_disabled++; | |
1530 | ||
d221938c | 1531 | cpu_maps_update_done(); |
e3920fb4 RW |
1532 | return error; |
1533 | } | |
1534 | ||
56555855 | 1535 | void __weak arch_thaw_secondary_cpus_begin(void) |
d0af9eed SS |
1536 | { |
1537 | } | |
1538 | ||
56555855 | 1539 | void __weak arch_thaw_secondary_cpus_end(void) |
d0af9eed SS |
1540 | { |
1541 | } | |
1542 | ||
56555855 | 1543 | void thaw_secondary_cpus(void) |
e3920fb4 RW |
1544 | { |
1545 | int cpu, error; | |
1546 | ||
1547 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1548 | cpu_maps_update_begin(); |
01b41159 | 1549 | __cpu_hotplug_enable(); |
e0b582ec | 1550 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1551 | goto out; |
e3920fb4 | 1552 | |
84117da5 | 1553 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed | 1554 | |
56555855 | 1555 | arch_thaw_secondary_cpus_begin(); |
d0af9eed | 1556 | |
e0b582ec | 1557 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1558 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1559 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1560 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1561 | if (!error) { |
84117da5 | 1562 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1563 | continue; |
1564 | } | |
84117da5 | 1565 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1566 | } |
d0af9eed | 1567 | |
56555855 | 1568 | arch_thaw_secondary_cpus_end(); |
d0af9eed | 1569 | |
e0b582ec | 1570 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1571 | out: |
d221938c | 1572 | cpu_maps_update_done(); |
1da177e4 | 1573 | } |
e0b582ec | 1574 | |
d7268a31 | 1575 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1576 | { |
1577 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1578 | return -ENOMEM; | |
1579 | return 0; | |
1580 | } | |
1581 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1582 | |
79cfbdfa SB |
1583 | /* |
1584 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1585 | * ensure that the state of the system with respect to the tasks being frozen | |
1586 | * or not, as reported by the notification, remains unchanged *throughout the | |
1587 | * duration* of the execution of the callbacks. | |
1588 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1589 | * | |
1590 | * This synchronization is implemented by mutually excluding regular CPU | |
1591 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1592 | * Hibernate notifications. | |
1593 | */ | |
1594 | static int | |
1595 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1596 | unsigned long action, void *ptr) | |
1597 | { | |
1598 | switch (action) { | |
1599 | ||
1600 | case PM_SUSPEND_PREPARE: | |
1601 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1602 | cpu_hotplug_disable(); |
79cfbdfa SB |
1603 | break; |
1604 | ||
1605 | case PM_POST_SUSPEND: | |
1606 | case PM_POST_HIBERNATION: | |
16e53dbf | 1607 | cpu_hotplug_enable(); |
79cfbdfa SB |
1608 | break; |
1609 | ||
1610 | default: | |
1611 | return NOTIFY_DONE; | |
1612 | } | |
1613 | ||
1614 | return NOTIFY_OK; | |
1615 | } | |
1616 | ||
1617 | ||
d7268a31 | 1618 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1619 | { |
6e32d479 FY |
1620 | /* |
1621 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1622 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1623 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1624 | */ | |
79cfbdfa SB |
1625 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1626 | return 0; | |
1627 | } | |
1628 | core_initcall(cpu_hotplug_pm_sync_init); | |
1629 | ||
f3de4be9 | 1630 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1631 | |
8ce371f9 PZ |
1632 | int __boot_cpu_id; |
1633 | ||
68f4f1ec | 1634 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1635 | |
cff7d378 | 1636 | /* Boot processor state steps */ |
17a2f1ce | 1637 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1638 | [CPUHP_OFFLINE] = { |
1639 | .name = "offline", | |
3c1627e9 TG |
1640 | .startup.single = NULL, |
1641 | .teardown.single = NULL, | |
cff7d378 TG |
1642 | }, |
1643 | #ifdef CONFIG_SMP | |
1644 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1645 | .name = "threads:prepare", |
3c1627e9 TG |
1646 | .startup.single = smpboot_create_threads, |
1647 | .teardown.single = NULL, | |
757c989b | 1648 | .cant_stop = true, |
cff7d378 | 1649 | }, |
00e16c3d | 1650 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1651 | .name = "perf:prepare", |
1652 | .startup.single = perf_event_init_cpu, | |
1653 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1654 | }, |
7ee681b2 | 1655 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1656 | .name = "workqueue:prepare", |
1657 | .startup.single = workqueue_prepare_cpu, | |
1658 | .teardown.single = NULL, | |
7ee681b2 | 1659 | }, |
27590dc1 | 1660 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1661 | .name = "hrtimers:prepare", |
1662 | .startup.single = hrtimers_prepare_cpu, | |
1663 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1664 | }, |
31487f83 | 1665 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1666 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1667 | .startup.single = smpcfd_prepare_cpu, |
1668 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1669 | }, |
e6d4989a RW |
1670 | [CPUHP_RELAY_PREPARE] = { |
1671 | .name = "relay:prepare", | |
1672 | .startup.single = relay_prepare_cpu, | |
1673 | .teardown.single = NULL, | |
1674 | }, | |
6731d4f1 SAS |
1675 | [CPUHP_SLAB_PREPARE] = { |
1676 | .name = "slab:prepare", | |
1677 | .startup.single = slab_prepare_cpu, | |
1678 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1679 | }, |
4df83742 | 1680 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1681 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1682 | .startup.single = rcutree_prepare_cpu, |
1683 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1684 | }, |
4fae16df RC |
1685 | /* |
1686 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1687 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1688 | * otherwise a RCU stall occurs. | |
1689 | */ | |
26456f87 | 1690 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1691 | .name = "timers:prepare", |
26456f87 | 1692 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1693 | .teardown.single = timers_dead_cpu, |
4fae16df | 1694 | }, |
d10ef6f9 | 1695 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1696 | [CPUHP_BRINGUP_CPU] = { |
1697 | .name = "cpu:bringup", | |
3c1627e9 | 1698 | .startup.single = bringup_cpu, |
bf2c59fc | 1699 | .teardown.single = finish_cpu, |
757c989b | 1700 | .cant_stop = true, |
4baa0afc | 1701 | }, |
d10ef6f9 TG |
1702 | /* Final state before CPU kills itself */ |
1703 | [CPUHP_AP_IDLE_DEAD] = { | |
1704 | .name = "idle:dead", | |
1705 | }, | |
1706 | /* | |
1707 | * Last state before CPU enters the idle loop to die. Transient state | |
1708 | * for synchronization. | |
1709 | */ | |
1710 | [CPUHP_AP_OFFLINE] = { | |
1711 | .name = "ap:offline", | |
1712 | .cant_stop = true, | |
1713 | }, | |
9cf7243d TG |
1714 | /* First state is scheduler control. Interrupts are disabled */ |
1715 | [CPUHP_AP_SCHED_STARTING] = { | |
1716 | .name = "sched:starting", | |
3c1627e9 TG |
1717 | .startup.single = sched_cpu_starting, |
1718 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1719 | }, |
4df83742 | 1720 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1721 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1722 | .startup.single = NULL, |
1723 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1724 | }, |
46febd37 LJ |
1725 | [CPUHP_AP_SMPCFD_DYING] = { |
1726 | .name = "smpcfd:dying", | |
1727 | .startup.single = NULL, | |
1728 | .teardown.single = smpcfd_dying_cpu, | |
1729 | }, | |
d10ef6f9 TG |
1730 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1731 | * state for synchronsization */ | |
1732 | [CPUHP_AP_ONLINE] = { | |
1733 | .name = "ap:online", | |
1734 | }, | |
17a2f1ce | 1735 | /* |
1cf12e08 | 1736 | * Handled on control processor until the plugged processor manages |
17a2f1ce LJ |
1737 | * this itself. |
1738 | */ | |
1739 | [CPUHP_TEARDOWN_CPU] = { | |
1740 | .name = "cpu:teardown", | |
1741 | .startup.single = NULL, | |
1742 | .teardown.single = takedown_cpu, | |
1743 | .cant_stop = true, | |
1744 | }, | |
1cf12e08 TG |
1745 | |
1746 | [CPUHP_AP_SCHED_WAIT_EMPTY] = { | |
1747 | .name = "sched:waitempty", | |
1748 | .startup.single = NULL, | |
1749 | .teardown.single = sched_cpu_wait_empty, | |
1750 | }, | |
1751 | ||
d10ef6f9 | 1752 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1753 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1754 | .name = "smpboot/threads:online", |
3c1627e9 | 1755 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1756 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1757 | }, |
c5cb83bb TG |
1758 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1759 | .name = "irq/affinity:online", | |
1760 | .startup.single = irq_affinity_online_cpu, | |
1761 | .teardown.single = NULL, | |
1762 | }, | |
00e16c3d | 1763 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1764 | .name = "perf:online", |
1765 | .startup.single = perf_event_init_cpu, | |
1766 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1767 | }, |
9cf57731 PZ |
1768 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1769 | .name = "lockup_detector:online", | |
1770 | .startup.single = lockup_detector_online_cpu, | |
1771 | .teardown.single = lockup_detector_offline_cpu, | |
1772 | }, | |
7ee681b2 | 1773 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1774 | .name = "workqueue:online", |
1775 | .startup.single = workqueue_online_cpu, | |
1776 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1777 | }, |
4df83742 | 1778 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1779 | .name = "RCU/tree:online", |
3c1627e9 TG |
1780 | .startup.single = rcutree_online_cpu, |
1781 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1782 | }, |
4baa0afc | 1783 | #endif |
d10ef6f9 TG |
1784 | /* |
1785 | * The dynamically registered state space is here | |
1786 | */ | |
1787 | ||
aaddd7d1 TG |
1788 | #ifdef CONFIG_SMP |
1789 | /* Last state is scheduler control setting the cpu active */ | |
1790 | [CPUHP_AP_ACTIVE] = { | |
1791 | .name = "sched:active", | |
3c1627e9 TG |
1792 | .startup.single = sched_cpu_activate, |
1793 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1794 | }, |
1795 | #endif | |
1796 | ||
d10ef6f9 | 1797 | /* CPU is fully up and running. */ |
4baa0afc TG |
1798 | [CPUHP_ONLINE] = { |
1799 | .name = "online", | |
3c1627e9 TG |
1800 | .startup.single = NULL, |
1801 | .teardown.single = NULL, | |
4baa0afc TG |
1802 | }, |
1803 | }; | |
1804 | ||
5b7aa87e TG |
1805 | /* Sanity check for callbacks */ |
1806 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1807 | { | |
1808 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1809 | return -EINVAL; | |
1810 | return 0; | |
1811 | } | |
1812 | ||
dc280d93 TG |
1813 | /* |
1814 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1815 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1816 | * by having no name assigned. | |
1817 | */ | |
1818 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1819 | { | |
4205e478 TG |
1820 | enum cpuhp_state i, end; |
1821 | struct cpuhp_step *step; | |
dc280d93 | 1822 | |
4205e478 TG |
1823 | switch (state) { |
1824 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1825 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1826 | end = CPUHP_AP_ONLINE_DYN_END; |
1827 | break; | |
1828 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1829 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1830 | end = CPUHP_BP_PREPARE_DYN_END; |
1831 | break; | |
1832 | default: | |
1833 | return -EINVAL; | |
1834 | } | |
1835 | ||
1836 | for (i = state; i <= end; i++, step++) { | |
1837 | if (!step->name) | |
dc280d93 TG |
1838 | return i; |
1839 | } | |
1840 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1841 | return -ENOSPC; | |
1842 | } | |
1843 | ||
1844 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1845 | int (*startup)(unsigned int cpu), | |
1846 | int (*teardown)(unsigned int cpu), | |
1847 | bool multi_instance) | |
5b7aa87e TG |
1848 | { |
1849 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1850 | struct cpuhp_step *sp; | |
dc280d93 | 1851 | int ret = 0; |
5b7aa87e | 1852 | |
0c96b273 EB |
1853 | /* |
1854 | * If name is NULL, then the state gets removed. | |
1855 | * | |
1856 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1857 | * the first allocation from these dynamic ranges, so the removal | |
1858 | * would trigger a new allocation and clear the wrong (already | |
1859 | * empty) state, leaving the callbacks of the to be cleared state | |
1860 | * dangling, which causes wreckage on the next hotplug operation. | |
1861 | */ | |
1862 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1863 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1864 | ret = cpuhp_reserve_state(state); |
1865 | if (ret < 0) | |
dc434e05 | 1866 | return ret; |
dc280d93 TG |
1867 | state = ret; |
1868 | } | |
5b7aa87e | 1869 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1870 | if (name && sp->name) |
1871 | return -EBUSY; | |
1872 | ||
3c1627e9 TG |
1873 | sp->startup.single = startup; |
1874 | sp->teardown.single = teardown; | |
5b7aa87e | 1875 | sp->name = name; |
cf392d10 TG |
1876 | sp->multi_instance = multi_instance; |
1877 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1878 | return ret; |
5b7aa87e TG |
1879 | } |
1880 | ||
1881 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1882 | { | |
3c1627e9 | 1883 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1884 | } |
1885 | ||
5b7aa87e TG |
1886 | /* |
1887 | * Call the startup/teardown function for a step either on the AP or | |
1888 | * on the current CPU. | |
1889 | */ | |
cf392d10 TG |
1890 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1891 | struct hlist_node *node) | |
5b7aa87e | 1892 | { |
a724632c | 1893 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1894 | int ret; |
1895 | ||
4dddfb5f PZ |
1896 | /* |
1897 | * If there's nothing to do, we done. | |
1898 | * Relies on the union for multi_instance. | |
1899 | */ | |
453e4108 | 1900 | if (cpuhp_step_empty(bringup, sp)) |
5b7aa87e | 1901 | return 0; |
5b7aa87e TG |
1902 | /* |
1903 | * The non AP bound callbacks can fail on bringup. On teardown | |
1904 | * e.g. module removal we crash for now. | |
1905 | */ | |
1cf4f629 TG |
1906 | #ifdef CONFIG_SMP |
1907 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1908 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1909 | else |
96abb968 | 1910 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1911 | #else |
96abb968 | 1912 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1913 | #endif |
5b7aa87e TG |
1914 | BUG_ON(ret && !bringup); |
1915 | return ret; | |
1916 | } | |
1917 | ||
1918 | /* | |
1919 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1920 | * | |
1921 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1922 | */ | |
1923 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1924 | struct hlist_node *node) |
5b7aa87e TG |
1925 | { |
1926 | int cpu; | |
1927 | ||
5b7aa87e TG |
1928 | /* Roll back the already executed steps on the other cpus */ |
1929 | for_each_present_cpu(cpu) { | |
1930 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1931 | int cpustate = st->state; | |
1932 | ||
1933 | if (cpu >= failedcpu) | |
1934 | break; | |
1935 | ||
1936 | /* Did we invoke the startup call on that cpu ? */ | |
1937 | if (cpustate >= state) | |
cf392d10 | 1938 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1939 | } |
1940 | } | |
1941 | ||
9805c673 TG |
1942 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1943 | struct hlist_node *node, | |
1944 | bool invoke) | |
cf392d10 TG |
1945 | { |
1946 | struct cpuhp_step *sp; | |
1947 | int cpu; | |
1948 | int ret; | |
1949 | ||
9805c673 TG |
1950 | lockdep_assert_cpus_held(); |
1951 | ||
cf392d10 TG |
1952 | sp = cpuhp_get_step(state); |
1953 | if (sp->multi_instance == false) | |
1954 | return -EINVAL; | |
1955 | ||
dc434e05 | 1956 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1957 | |
3c1627e9 | 1958 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1959 | goto add_node; |
1960 | ||
1961 | /* | |
1962 | * Try to call the startup callback for each present cpu | |
1963 | * depending on the hotplug state of the cpu. | |
1964 | */ | |
1965 | for_each_present_cpu(cpu) { | |
1966 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1967 | int cpustate = st->state; | |
1968 | ||
1969 | if (cpustate < state) | |
1970 | continue; | |
1971 | ||
1972 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1973 | if (ret) { | |
3c1627e9 | 1974 | if (sp->teardown.multi) |
cf392d10 | 1975 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1976 | goto unlock; |
cf392d10 TG |
1977 | } |
1978 | } | |
1979 | add_node: | |
1980 | ret = 0; | |
cf392d10 | 1981 | hlist_add_head(node, &sp->list); |
dc434e05 | 1982 | unlock: |
cf392d10 | 1983 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1984 | return ret; |
1985 | } | |
1986 | ||
1987 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1988 | bool invoke) | |
1989 | { | |
1990 | int ret; | |
1991 | ||
1992 | cpus_read_lock(); | |
1993 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1994 | cpus_read_unlock(); |
cf392d10 TG |
1995 | return ret; |
1996 | } | |
1997 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1998 | ||
5b7aa87e | 1999 | /** |
71def423 | 2000 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 | 2001 | * @state: The state to setup |
ed3cd1da | 2002 | * @name: Name of the step |
dc280d93 TG |
2003 | * @invoke: If true, the startup function is invoked for cpus where |
2004 | * cpu state >= @state | |
2005 | * @startup: startup callback function | |
2006 | * @teardown: teardown callback function | |
2007 | * @multi_instance: State is set up for multiple instances which get | |
2008 | * added afterwards. | |
5b7aa87e | 2009 | * |
71def423 | 2010 | * The caller needs to hold cpus read locked while calling this function. |
11bc021d | 2011 | * Return: |
512f0980 | 2012 | * On success: |
11bc021d | 2013 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN; |
512f0980 BO |
2014 | * 0 for all other states |
2015 | * On failure: proper (negative) error code | |
5b7aa87e | 2016 | */ |
71def423 SAS |
2017 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
2018 | const char *name, bool invoke, | |
2019 | int (*startup)(unsigned int cpu), | |
2020 | int (*teardown)(unsigned int cpu), | |
2021 | bool multi_instance) | |
5b7aa87e TG |
2022 | { |
2023 | int cpu, ret = 0; | |
b9d9d691 | 2024 | bool dynstate; |
5b7aa87e | 2025 | |
71def423 SAS |
2026 | lockdep_assert_cpus_held(); |
2027 | ||
5b7aa87e TG |
2028 | if (cpuhp_cb_check(state) || !name) |
2029 | return -EINVAL; | |
2030 | ||
dc434e05 | 2031 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 2032 | |
dc280d93 TG |
2033 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
2034 | multi_instance); | |
5b7aa87e | 2035 | |
b9d9d691 TG |
2036 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
2037 | if (ret > 0 && dynstate) { | |
2038 | state = ret; | |
2039 | ret = 0; | |
2040 | } | |
2041 | ||
dc280d93 | 2042 | if (ret || !invoke || !startup) |
5b7aa87e TG |
2043 | goto out; |
2044 | ||
2045 | /* | |
2046 | * Try to call the startup callback for each present cpu | |
2047 | * depending on the hotplug state of the cpu. | |
2048 | */ | |
2049 | for_each_present_cpu(cpu) { | |
2050 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2051 | int cpustate = st->state; | |
2052 | ||
2053 | if (cpustate < state) | |
2054 | continue; | |
2055 | ||
cf392d10 | 2056 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 2057 | if (ret) { |
a724632c | 2058 | if (teardown) |
cf392d10 TG |
2059 | cpuhp_rollback_install(cpu, state, NULL); |
2060 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
2061 | goto out; |
2062 | } | |
2063 | } | |
2064 | out: | |
dc434e05 | 2065 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
2066 | /* |
2067 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
2068 | * dynamically allocated state in case of success. | |
2069 | */ | |
b9d9d691 | 2070 | if (!ret && dynstate) |
5b7aa87e TG |
2071 | return state; |
2072 | return ret; | |
2073 | } | |
71def423 SAS |
2074 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
2075 | ||
2076 | int __cpuhp_setup_state(enum cpuhp_state state, | |
2077 | const char *name, bool invoke, | |
2078 | int (*startup)(unsigned int cpu), | |
2079 | int (*teardown)(unsigned int cpu), | |
2080 | bool multi_instance) | |
2081 | { | |
2082 | int ret; | |
2083 | ||
2084 | cpus_read_lock(); | |
2085 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
2086 | teardown, multi_instance); | |
2087 | cpus_read_unlock(); | |
2088 | return ret; | |
2089 | } | |
5b7aa87e TG |
2090 | EXPORT_SYMBOL(__cpuhp_setup_state); |
2091 | ||
cf392d10 TG |
2092 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
2093 | struct hlist_node *node, bool invoke) | |
2094 | { | |
2095 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
2096 | int cpu; | |
2097 | ||
2098 | BUG_ON(cpuhp_cb_check(state)); | |
2099 | ||
2100 | if (!sp->multi_instance) | |
2101 | return -EINVAL; | |
2102 | ||
8f553c49 | 2103 | cpus_read_lock(); |
dc434e05 SAS |
2104 | mutex_lock(&cpuhp_state_mutex); |
2105 | ||
cf392d10 TG |
2106 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
2107 | goto remove; | |
2108 | /* | |
2109 | * Call the teardown callback for each present cpu depending | |
2110 | * on the hotplug state of the cpu. This function is not | |
2111 | * allowed to fail currently! | |
2112 | */ | |
2113 | for_each_present_cpu(cpu) { | |
2114 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2115 | int cpustate = st->state; | |
2116 | ||
2117 | if (cpustate >= state) | |
2118 | cpuhp_issue_call(cpu, state, false, node); | |
2119 | } | |
2120 | ||
2121 | remove: | |
cf392d10 TG |
2122 | hlist_del(node); |
2123 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 2124 | cpus_read_unlock(); |
cf392d10 TG |
2125 | |
2126 | return 0; | |
2127 | } | |
2128 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 2129 | |
5b7aa87e | 2130 | /** |
71def423 | 2131 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
2132 | * @state: The state to remove |
2133 | * @invoke: If true, the teardown function is invoked for cpus where | |
2134 | * cpu state >= @state | |
2135 | * | |
71def423 | 2136 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
2137 | * The teardown callback is currently not allowed to fail. Think |
2138 | * about module removal! | |
2139 | */ | |
71def423 | 2140 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 2141 | { |
cf392d10 | 2142 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
2143 | int cpu; |
2144 | ||
2145 | BUG_ON(cpuhp_cb_check(state)); | |
2146 | ||
71def423 | 2147 | lockdep_assert_cpus_held(); |
5b7aa87e | 2148 | |
dc434e05 | 2149 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
2150 | if (sp->multi_instance) { |
2151 | WARN(!hlist_empty(&sp->list), | |
2152 | "Error: Removing state %d which has instances left.\n", | |
2153 | state); | |
2154 | goto remove; | |
2155 | } | |
2156 | ||
a724632c | 2157 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
2158 | goto remove; |
2159 | ||
2160 | /* | |
2161 | * Call the teardown callback for each present cpu depending | |
2162 | * on the hotplug state of the cpu. This function is not | |
2163 | * allowed to fail currently! | |
2164 | */ | |
2165 | for_each_present_cpu(cpu) { | |
2166 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2167 | int cpustate = st->state; | |
2168 | ||
2169 | if (cpustate >= state) | |
cf392d10 | 2170 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
2171 | } |
2172 | remove: | |
cf392d10 | 2173 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 2174 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
2175 | } |
2176 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
2177 | ||
2178 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
2179 | { | |
2180 | cpus_read_lock(); | |
2181 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 2182 | cpus_read_unlock(); |
5b7aa87e TG |
2183 | } |
2184 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
2185 | ||
dc8d37ed AB |
2186 | #ifdef CONFIG_HOTPLUG_SMT |
2187 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2188 | { | |
2189 | struct device *dev = get_cpu_device(cpu); | |
2190 | ||
2191 | dev->offline = true; | |
2192 | /* Tell user space about the state change */ | |
2193 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2194 | } | |
2195 | ||
2196 | static void cpuhp_online_cpu_device(unsigned int cpu) | |
2197 | { | |
2198 | struct device *dev = get_cpu_device(cpu); | |
2199 | ||
2200 | dev->offline = false; | |
2201 | /* Tell user space about the state change */ | |
2202 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2203 | } | |
2204 | ||
2205 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) | |
2206 | { | |
2207 | int cpu, ret = 0; | |
2208 | ||
2209 | cpu_maps_update_begin(); | |
2210 | for_each_online_cpu(cpu) { | |
2211 | if (topology_is_primary_thread(cpu)) | |
2212 | continue; | |
2213 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2214 | if (ret) | |
2215 | break; | |
2216 | /* | |
2217 | * As this needs to hold the cpu maps lock it's impossible | |
2218 | * to call device_offline() because that ends up calling | |
2219 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2220 | * needs to be held as this might race against in kernel | |
2221 | * abusers of the hotplug machinery (thermal management). | |
2222 | * | |
2223 | * So nothing would update device:offline state. That would | |
2224 | * leave the sysfs entry stale and prevent onlining after | |
2225 | * smt control has been changed to 'off' again. This is | |
2226 | * called under the sysfs hotplug lock, so it is properly | |
2227 | * serialized against the regular offline usage. | |
2228 | */ | |
2229 | cpuhp_offline_cpu_device(cpu); | |
2230 | } | |
2231 | if (!ret) | |
2232 | cpu_smt_control = ctrlval; | |
2233 | cpu_maps_update_done(); | |
2234 | return ret; | |
2235 | } | |
2236 | ||
2237 | int cpuhp_smt_enable(void) | |
2238 | { | |
2239 | int cpu, ret = 0; | |
2240 | ||
2241 | cpu_maps_update_begin(); | |
2242 | cpu_smt_control = CPU_SMT_ENABLED; | |
2243 | for_each_present_cpu(cpu) { | |
2244 | /* Skip online CPUs and CPUs on offline nodes */ | |
2245 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2246 | continue; | |
2247 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2248 | if (ret) | |
2249 | break; | |
2250 | /* See comment in cpuhp_smt_disable() */ | |
2251 | cpuhp_online_cpu_device(cpu); | |
2252 | } | |
2253 | cpu_maps_update_done(); | |
2254 | return ret; | |
2255 | } | |
2256 | #endif | |
2257 | ||
98f8cdce | 2258 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1782dc87 Y |
2259 | static ssize_t state_show(struct device *dev, |
2260 | struct device_attribute *attr, char *buf) | |
98f8cdce TG |
2261 | { |
2262 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2263 | ||
2264 | return sprintf(buf, "%d\n", st->state); | |
2265 | } | |
1782dc87 | 2266 | static DEVICE_ATTR_RO(state); |
98f8cdce | 2267 | |
1782dc87 Y |
2268 | static ssize_t target_store(struct device *dev, struct device_attribute *attr, |
2269 | const char *buf, size_t count) | |
757c989b TG |
2270 | { |
2271 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2272 | struct cpuhp_step *sp; | |
2273 | int target, ret; | |
2274 | ||
2275 | ret = kstrtoint(buf, 10, &target); | |
2276 | if (ret) | |
2277 | return ret; | |
2278 | ||
2279 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
2280 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
2281 | return -EINVAL; | |
2282 | #else | |
2283 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
2284 | return -EINVAL; | |
2285 | #endif | |
2286 | ||
2287 | ret = lock_device_hotplug_sysfs(); | |
2288 | if (ret) | |
2289 | return ret; | |
2290 | ||
2291 | mutex_lock(&cpuhp_state_mutex); | |
2292 | sp = cpuhp_get_step(target); | |
2293 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
2294 | mutex_unlock(&cpuhp_state_mutex); | |
2295 | if (ret) | |
40da1b11 | 2296 | goto out; |
757c989b TG |
2297 | |
2298 | if (st->state < target) | |
33c3736e | 2299 | ret = cpu_up(dev->id, target); |
757c989b | 2300 | else |
33c3736e | 2301 | ret = cpu_down(dev->id, target); |
40da1b11 | 2302 | out: |
757c989b TG |
2303 | unlock_device_hotplug(); |
2304 | return ret ? ret : count; | |
2305 | } | |
2306 | ||
1782dc87 Y |
2307 | static ssize_t target_show(struct device *dev, |
2308 | struct device_attribute *attr, char *buf) | |
98f8cdce TG |
2309 | { |
2310 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2311 | ||
2312 | return sprintf(buf, "%d\n", st->target); | |
2313 | } | |
1782dc87 | 2314 | static DEVICE_ATTR_RW(target); |
1db49484 | 2315 | |
1782dc87 Y |
2316 | static ssize_t fail_store(struct device *dev, struct device_attribute *attr, |
2317 | const char *buf, size_t count) | |
1db49484 PZ |
2318 | { |
2319 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2320 | struct cpuhp_step *sp; | |
2321 | int fail, ret; | |
2322 | ||
2323 | ret = kstrtoint(buf, 10, &fail); | |
2324 | if (ret) | |
2325 | return ret; | |
2326 | ||
3ae70c25 VD |
2327 | if (fail == CPUHP_INVALID) { |
2328 | st->fail = fail; | |
2329 | return count; | |
2330 | } | |
2331 | ||
33d4a5a7 ET |
2332 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
2333 | return -EINVAL; | |
2334 | ||
1db49484 PZ |
2335 | /* |
2336 | * Cannot fail STARTING/DYING callbacks. | |
2337 | */ | |
2338 | if (cpuhp_is_atomic_state(fail)) | |
2339 | return -EINVAL; | |
2340 | ||
62f25069 VD |
2341 | /* |
2342 | * DEAD callbacks cannot fail... | |
2343 | * ... neither can CPUHP_BRINGUP_CPU during hotunplug. The latter | |
2344 | * triggering STARTING callbacks, a failure in this state would | |
2345 | * hinder rollback. | |
2346 | */ | |
2347 | if (fail <= CPUHP_BRINGUP_CPU && st->state > CPUHP_BRINGUP_CPU) | |
2348 | return -EINVAL; | |
2349 | ||
1db49484 PZ |
2350 | /* |
2351 | * Cannot fail anything that doesn't have callbacks. | |
2352 | */ | |
2353 | mutex_lock(&cpuhp_state_mutex); | |
2354 | sp = cpuhp_get_step(fail); | |
2355 | if (!sp->startup.single && !sp->teardown.single) | |
2356 | ret = -EINVAL; | |
2357 | mutex_unlock(&cpuhp_state_mutex); | |
2358 | if (ret) | |
2359 | return ret; | |
2360 | ||
2361 | st->fail = fail; | |
2362 | ||
2363 | return count; | |
2364 | } | |
2365 | ||
1782dc87 Y |
2366 | static ssize_t fail_show(struct device *dev, |
2367 | struct device_attribute *attr, char *buf) | |
1db49484 PZ |
2368 | { |
2369 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2370 | ||
2371 | return sprintf(buf, "%d\n", st->fail); | |
2372 | } | |
2373 | ||
1782dc87 | 2374 | static DEVICE_ATTR_RW(fail); |
1db49484 | 2375 | |
98f8cdce TG |
2376 | static struct attribute *cpuhp_cpu_attrs[] = { |
2377 | &dev_attr_state.attr, | |
2378 | &dev_attr_target.attr, | |
1db49484 | 2379 | &dev_attr_fail.attr, |
98f8cdce TG |
2380 | NULL |
2381 | }; | |
2382 | ||
993647a2 | 2383 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2384 | .attrs = cpuhp_cpu_attrs, |
2385 | .name = "hotplug", | |
2386 | NULL | |
2387 | }; | |
2388 | ||
1782dc87 | 2389 | static ssize_t states_show(struct device *dev, |
98f8cdce TG |
2390 | struct device_attribute *attr, char *buf) |
2391 | { | |
2392 | ssize_t cur, res = 0; | |
2393 | int i; | |
2394 | ||
2395 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2396 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2397 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2398 | ||
2399 | if (sp->name) { | |
2400 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2401 | buf += cur; | |
2402 | res += cur; | |
2403 | } | |
2404 | } | |
2405 | mutex_unlock(&cpuhp_state_mutex); | |
2406 | return res; | |
2407 | } | |
1782dc87 | 2408 | static DEVICE_ATTR_RO(states); |
98f8cdce TG |
2409 | |
2410 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2411 | &dev_attr_states.attr, | |
2412 | NULL | |
2413 | }; | |
2414 | ||
993647a2 | 2415 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2416 | .attrs = cpuhp_cpu_root_attrs, |
2417 | .name = "hotplug", | |
2418 | NULL | |
2419 | }; | |
2420 | ||
05736e4a TG |
2421 | #ifdef CONFIG_HOTPLUG_SMT |
2422 | ||
05736e4a | 2423 | static ssize_t |
de7b77e5 JP |
2424 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2425 | const char *buf, size_t count) | |
05736e4a TG |
2426 | { |
2427 | int ctrlval, ret; | |
2428 | ||
2429 | if (sysfs_streq(buf, "on")) | |
2430 | ctrlval = CPU_SMT_ENABLED; | |
2431 | else if (sysfs_streq(buf, "off")) | |
2432 | ctrlval = CPU_SMT_DISABLED; | |
2433 | else if (sysfs_streq(buf, "forceoff")) | |
2434 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2435 | else | |
2436 | return -EINVAL; | |
2437 | ||
2438 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2439 | return -EPERM; | |
2440 | ||
2441 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2442 | return -ENODEV; | |
2443 | ||
2444 | ret = lock_device_hotplug_sysfs(); | |
2445 | if (ret) | |
2446 | return ret; | |
2447 | ||
2448 | if (ctrlval != cpu_smt_control) { | |
2449 | switch (ctrlval) { | |
2450 | case CPU_SMT_ENABLED: | |
215af549 | 2451 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2452 | break; |
2453 | case CPU_SMT_DISABLED: | |
2454 | case CPU_SMT_FORCE_DISABLED: | |
2455 | ret = cpuhp_smt_disable(ctrlval); | |
2456 | break; | |
2457 | } | |
2458 | } | |
2459 | ||
2460 | unlock_device_hotplug(); | |
2461 | return ret ? ret : count; | |
2462 | } | |
de7b77e5 JP |
2463 | |
2464 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2465 | static ssize_t | |
2466 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2467 | const char *buf, size_t count) | |
2468 | { | |
2469 | return -ENODEV; | |
2470 | } | |
2471 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2472 | ||
2473 | static const char *smt_states[] = { | |
2474 | [CPU_SMT_ENABLED] = "on", | |
2475 | [CPU_SMT_DISABLED] = "off", | |
2476 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2477 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2478 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2479 | }; | |
2480 | ||
1782dc87 Y |
2481 | static ssize_t control_show(struct device *dev, |
2482 | struct device_attribute *attr, char *buf) | |
de7b77e5 JP |
2483 | { |
2484 | const char *state = smt_states[cpu_smt_control]; | |
2485 | ||
2486 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2487 | } | |
2488 | ||
1782dc87 Y |
2489 | static ssize_t control_store(struct device *dev, struct device_attribute *attr, |
2490 | const char *buf, size_t count) | |
de7b77e5 JP |
2491 | { |
2492 | return __store_smt_control(dev, attr, buf, count); | |
2493 | } | |
1782dc87 | 2494 | static DEVICE_ATTR_RW(control); |
05736e4a | 2495 | |
1782dc87 Y |
2496 | static ssize_t active_show(struct device *dev, |
2497 | struct device_attribute *attr, char *buf) | |
05736e4a | 2498 | { |
de7b77e5 | 2499 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a | 2500 | } |
1782dc87 | 2501 | static DEVICE_ATTR_RO(active); |
05736e4a TG |
2502 | |
2503 | static struct attribute *cpuhp_smt_attrs[] = { | |
2504 | &dev_attr_control.attr, | |
2505 | &dev_attr_active.attr, | |
2506 | NULL | |
2507 | }; | |
2508 | ||
2509 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2510 | .attrs = cpuhp_smt_attrs, | |
2511 | .name = "smt", | |
2512 | NULL | |
2513 | }; | |
2514 | ||
de7b77e5 | 2515 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2516 | { |
05736e4a TG |
2517 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2518 | &cpuhp_smt_attr_group); | |
2519 | } | |
2520 | ||
98f8cdce TG |
2521 | static int __init cpuhp_sysfs_init(void) |
2522 | { | |
2523 | int cpu, ret; | |
2524 | ||
de7b77e5 | 2525 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2526 | if (ret) |
2527 | return ret; | |
2528 | ||
98f8cdce TG |
2529 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2530 | &cpuhp_cpu_root_attr_group); | |
2531 | if (ret) | |
2532 | return ret; | |
2533 | ||
2534 | for_each_possible_cpu(cpu) { | |
2535 | struct device *dev = get_cpu_device(cpu); | |
2536 | ||
2537 | if (!dev) | |
2538 | continue; | |
2539 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2540 | if (ret) | |
2541 | return ret; | |
2542 | } | |
2543 | return 0; | |
2544 | } | |
2545 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2546 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2547 | |
e56b3bc7 LT |
2548 | /* |
2549 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2550 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2551 | * | |
e0b582ec | 2552 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2553 | * mask value that has a single bit set only. |
2554 | */ | |
b8d317d1 | 2555 | |
e56b3bc7 | 2556 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2557 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2558 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2559 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2560 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2561 | |
e56b3bc7 LT |
2562 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2563 | ||
2564 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2565 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2566 | #if BITS_PER_LONG > 32 | |
2567 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2568 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2569 | #endif |
2570 | }; | |
e56b3bc7 | 2571 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2572 | |
2573 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2574 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2575 | |
2576 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2577 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2578 | = {CPU_BITS_ALL}; |
b3199c02 | 2579 | #else |
4b804c85 | 2580 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2581 | #endif |
4b804c85 | 2582 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2583 | |
4b804c85 RV |
2584 | struct cpumask __cpu_online_mask __read_mostly; |
2585 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2586 | |
4b804c85 RV |
2587 | struct cpumask __cpu_present_mask __read_mostly; |
2588 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2589 | |
4b804c85 RV |
2590 | struct cpumask __cpu_active_mask __read_mostly; |
2591 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2592 | |
e40f74c5 PZ |
2593 | struct cpumask __cpu_dying_mask __read_mostly; |
2594 | EXPORT_SYMBOL(__cpu_dying_mask); | |
2595 | ||
0c09ab96 TG |
2596 | atomic_t __num_online_cpus __read_mostly; |
2597 | EXPORT_SYMBOL(__num_online_cpus); | |
2598 | ||
3fa41520 RR |
2599 | void init_cpu_present(const struct cpumask *src) |
2600 | { | |
c4c54dd1 | 2601 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2602 | } |
2603 | ||
2604 | void init_cpu_possible(const struct cpumask *src) | |
2605 | { | |
c4c54dd1 | 2606 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2607 | } |
2608 | ||
2609 | void init_cpu_online(const struct cpumask *src) | |
2610 | { | |
c4c54dd1 | 2611 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2612 | } |
cff7d378 | 2613 | |
0c09ab96 TG |
2614 | void set_cpu_online(unsigned int cpu, bool online) |
2615 | { | |
2616 | /* | |
2617 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2618 | * function by the reboot and kexec code which invoke it from | |
2619 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2620 | * regular CPU hotplug is properly serialized. | |
2621 | * | |
2622 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2623 | * does not protect readers which are not serialized against | |
2624 | * concurrent hotplug operations. | |
2625 | */ | |
2626 | if (online) { | |
2627 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2628 | atomic_inc(&__num_online_cpus); | |
2629 | } else { | |
2630 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2631 | atomic_dec(&__num_online_cpus); | |
2632 | } | |
2633 | } | |
2634 | ||
cff7d378 TG |
2635 | /* |
2636 | * Activate the first processor. | |
2637 | */ | |
2638 | void __init boot_cpu_init(void) | |
2639 | { | |
2640 | int cpu = smp_processor_id(); | |
2641 | ||
2642 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2643 | set_cpu_online(cpu, true); | |
2644 | set_cpu_active(cpu, true); | |
2645 | set_cpu_present(cpu, true); | |
2646 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2647 | |
2648 | #ifdef CONFIG_SMP | |
2649 | __boot_cpu_id = cpu; | |
2650 | #endif | |
cff7d378 TG |
2651 | } |
2652 | ||
2653 | /* | |
2654 | * Must be called _AFTER_ setting up the per_cpu areas | |
2655 | */ | |
b5b1404d | 2656 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2657 | { |
269777aa | 2658 | #ifdef CONFIG_SMP |
e797bda3 | 2659 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2660 | #endif |
0cc3cd21 | 2661 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2662 | } |
98af8452 | 2663 | |
731dc9df TH |
2664 | /* |
2665 | * These are used for a global "mitigations=" cmdline option for toggling | |
2666 | * optional CPU mitigations. | |
2667 | */ | |
2668 | enum cpu_mitigations { | |
2669 | CPU_MITIGATIONS_OFF, | |
2670 | CPU_MITIGATIONS_AUTO, | |
2671 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2672 | }; | |
2673 | ||
2674 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2675 | CPU_MITIGATIONS_AUTO; | |
98af8452 JP |
2676 | |
2677 | static int __init mitigations_parse_cmdline(char *arg) | |
2678 | { | |
2679 | if (!strcmp(arg, "off")) | |
2680 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2681 | else if (!strcmp(arg, "auto")) | |
2682 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2683 | else if (!strcmp(arg, "auto,nosmt")) | |
2684 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2685 | else |
2686 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2687 | arg); | |
98af8452 JP |
2688 | |
2689 | return 0; | |
2690 | } | |
2691 | early_param("mitigations", mitigations_parse_cmdline); | |
731dc9df TH |
2692 | |
2693 | /* mitigations=off */ | |
2694 | bool cpu_mitigations_off(void) | |
2695 | { | |
2696 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2697 | } | |
2698 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2699 | ||
2700 | /* mitigations=auto,nosmt */ | |
2701 | bool cpu_mitigations_auto_nosmt(void) | |
2702 | { | |
2703 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2704 | } | |
2705 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |