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> |
dce1ca05 | 34 | #include <linux/scs.h> |
fc8dffd3 | 35 | #include <linux/percpu-rwsem.h> |
b22afcdf | 36 | #include <linux/cpuset.h> |
3191dd5a | 37 | #include <linux/random.h> |
bae1a962 | 38 | #include <linux/cc_platform.h> |
cff7d378 | 39 | |
bb3632c6 | 40 | #include <trace/events/power.h> |
cff7d378 TG |
41 | #define CREATE_TRACE_POINTS |
42 | #include <trace/events/cpuhp.h> | |
1da177e4 | 43 | |
38498a67 TG |
44 | #include "smpboot.h" |
45 | ||
cff7d378 | 46 | /** |
11bc021d | 47 | * struct cpuhp_cpu_state - Per cpu hotplug state storage |
cff7d378 TG |
48 | * @state: The current cpu state |
49 | * @target: The target state | |
11bc021d | 50 | * @fail: Current CPU hotplug callback state |
4cb28ced TG |
51 | * @thread: Pointer to the hotplug thread |
52 | * @should_run: Thread should execute | |
3b9d6da6 | 53 | * @rollback: Perform a rollback |
a724632c TG |
54 | * @single: Single callback invocation |
55 | * @bringup: Single callback bringup or teardown selector | |
11bc021d RD |
56 | * @cpu: CPU number |
57 | * @node: Remote CPU node; for multi-instance, do a | |
58 | * single entry callback for install/remove | |
59 | * @last: For multi-instance rollback, remember how far we got | |
a724632c | 60 | * @cb_state: The state for a single callback (install/uninstall) |
4cb28ced | 61 | * @result: Result of the operation |
5ebe7742 PZ |
62 | * @done_up: Signal completion to the issuer of the task for cpu-up |
63 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
64 | */ |
65 | struct cpuhp_cpu_state { | |
66 | enum cpuhp_state state; | |
67 | enum cpuhp_state target; | |
1db49484 | 68 | enum cpuhp_state fail; |
4cb28ced TG |
69 | #ifdef CONFIG_SMP |
70 | struct task_struct *thread; | |
71 | bool should_run; | |
3b9d6da6 | 72 | bool rollback; |
a724632c TG |
73 | bool single; |
74 | bool bringup; | |
cf392d10 | 75 | struct hlist_node *node; |
4dddfb5f | 76 | struct hlist_node *last; |
4cb28ced | 77 | enum cpuhp_state cb_state; |
4cb28ced | 78 | int result; |
5ebe7742 PZ |
79 | struct completion done_up; |
80 | struct completion done_down; | |
4cb28ced | 81 | #endif |
cff7d378 TG |
82 | }; |
83 | ||
1db49484 PZ |
84 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
85 | .fail = CPUHP_INVALID, | |
86 | }; | |
cff7d378 | 87 | |
e797bda3 TG |
88 | #ifdef CONFIG_SMP |
89 | cpumask_t cpus_booted_once_mask; | |
90 | #endif | |
91 | ||
49dfe2a6 | 92 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
93 | static struct lockdep_map cpuhp_state_up_map = |
94 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
95 | static struct lockdep_map cpuhp_state_down_map = | |
96 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
97 | ||
98 | ||
76dc6c09 | 99 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
100 | { |
101 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
102 | } | |
103 | ||
76dc6c09 | 104 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
105 | { |
106 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
107 | } | |
108 | #else | |
109 | ||
76dc6c09 MM |
110 | static inline void cpuhp_lock_acquire(bool bringup) { } |
111 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 112 | |
49dfe2a6 TG |
113 | #endif |
114 | ||
cff7d378 | 115 | /** |
11bc021d | 116 | * struct cpuhp_step - Hotplug state machine step |
cff7d378 TG |
117 | * @name: Name of the step |
118 | * @startup: Startup function of the step | |
119 | * @teardown: Teardown function of the step | |
757c989b | 120 | * @cant_stop: Bringup/teardown can't be stopped at this step |
11bc021d | 121 | * @multi_instance: State has multiple instances which get added afterwards |
cff7d378 TG |
122 | */ |
123 | struct cpuhp_step { | |
cf392d10 TG |
124 | const char *name; |
125 | union { | |
3c1627e9 TG |
126 | int (*single)(unsigned int cpu); |
127 | int (*multi)(unsigned int cpu, | |
128 | struct hlist_node *node); | |
129 | } startup; | |
cf392d10 | 130 | union { |
3c1627e9 TG |
131 | int (*single)(unsigned int cpu); |
132 | int (*multi)(unsigned int cpu, | |
133 | struct hlist_node *node); | |
134 | } teardown; | |
11bc021d | 135 | /* private: */ |
cf392d10 | 136 | struct hlist_head list; |
11bc021d | 137 | /* public: */ |
cf392d10 TG |
138 | bool cant_stop; |
139 | bool multi_instance; | |
cff7d378 TG |
140 | }; |
141 | ||
98f8cdce | 142 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 143 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 144 | |
a724632c TG |
145 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
146 | { | |
17a2f1ce | 147 | return cpuhp_hp_states + state; |
a724632c TG |
148 | } |
149 | ||
453e4108 VD |
150 | static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step) |
151 | { | |
152 | return bringup ? !step->startup.single : !step->teardown.single; | |
153 | } | |
154 | ||
cff7d378 | 155 | /** |
11bc021d | 156 | * cpuhp_invoke_callback - Invoke the callbacks for a given state |
cff7d378 | 157 | * @cpu: The cpu for which the callback should be invoked |
96abb968 | 158 | * @state: The state to do callbacks for |
a724632c | 159 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
160 | * @node: For multi-instance, do a single entry callback for install/remove |
161 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 162 | * |
cf392d10 | 163 | * Called from cpu hotplug and from the state register machinery. |
11bc021d RD |
164 | * |
165 | * Return: %0 on success or a negative errno code | |
cff7d378 | 166 | */ |
a724632c | 167 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
168 | bool bringup, struct hlist_node *node, |
169 | struct hlist_node **lastp) | |
cff7d378 TG |
170 | { |
171 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 172 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
173 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
174 | int (*cb)(unsigned int cpu); | |
175 | int ret, cnt; | |
176 | ||
1db49484 PZ |
177 | if (st->fail == state) { |
178 | st->fail = CPUHP_INVALID; | |
1db49484 PZ |
179 | return -EAGAIN; |
180 | } | |
181 | ||
453e4108 VD |
182 | if (cpuhp_step_empty(bringup, step)) { |
183 | WARN_ON_ONCE(1); | |
184 | return 0; | |
185 | } | |
186 | ||
cf392d10 | 187 | if (!step->multi_instance) { |
96abb968 | 188 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 189 | cb = bringup ? step->startup.single : step->teardown.single; |
453e4108 | 190 | |
a724632c | 191 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 192 | ret = cb(cpu); |
a724632c | 193 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
194 | return ret; |
195 | } | |
3c1627e9 | 196 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
197 | |
198 | /* Single invocation for instance add/remove */ | |
199 | if (node) { | |
96abb968 | 200 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
201 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
202 | ret = cbm(cpu, node); | |
203 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
204 | return ret; | |
205 | } | |
206 | ||
207 | /* State transition. Invoke on all instances */ | |
208 | cnt = 0; | |
209 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
210 | if (lastp && node == *lastp) |
211 | break; | |
212 | ||
cf392d10 TG |
213 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
214 | ret = cbm(cpu, node); | |
215 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
216 | if (ret) { |
217 | if (!lastp) | |
218 | goto err; | |
219 | ||
220 | *lastp = node; | |
221 | return ret; | |
222 | } | |
cf392d10 TG |
223 | cnt++; |
224 | } | |
96abb968 PZ |
225 | if (lastp) |
226 | *lastp = NULL; | |
cf392d10 TG |
227 | return 0; |
228 | err: | |
229 | /* Rollback the instances if one failed */ | |
3c1627e9 | 230 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
231 | if (!cbm) |
232 | return ret; | |
233 | ||
234 | hlist_for_each(node, &step->list) { | |
235 | if (!cnt--) | |
236 | break; | |
724a8688 PZ |
237 | |
238 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
239 | ret = cbm(cpu, node); | |
240 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
241 | /* | |
242 | * Rollback must not fail, | |
243 | */ | |
244 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
245 | } |
246 | return ret; | |
247 | } | |
248 | ||
98a79d6a | 249 | #ifdef CONFIG_SMP |
fcb3029a AB |
250 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
251 | { | |
252 | /* | |
253 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
254 | * purposes as that state is handled explicitly in cpu_down. | |
255 | */ | |
256 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
257 | } | |
258 | ||
5ebe7742 PZ |
259 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
260 | { | |
261 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
262 | wait_for_completion(done); | |
263 | } | |
264 | ||
265 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
266 | { | |
267 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
268 | complete(done); | |
269 | } | |
270 | ||
271 | /* | |
272 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
273 | */ | |
274 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
275 | { | |
276 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
277 | } | |
278 | ||
b3199c02 | 279 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 280 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
281 | bool cpuhp_tasks_frozen; |
282 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 283 | |
79a6cdeb | 284 | /* |
93ae4f97 SB |
285 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
286 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
287 | */ |
288 | void cpu_maps_update_begin(void) | |
289 | { | |
290 | mutex_lock(&cpu_add_remove_lock); | |
291 | } | |
292 | ||
293 | void cpu_maps_update_done(void) | |
294 | { | |
295 | mutex_unlock(&cpu_add_remove_lock); | |
296 | } | |
1da177e4 | 297 | |
fc8dffd3 TG |
298 | /* |
299 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
300 | * Should always be manipulated under cpu_add_remove_lock |
301 | */ | |
302 | static int cpu_hotplug_disabled; | |
303 | ||
79a6cdeb LJ |
304 | #ifdef CONFIG_HOTPLUG_CPU |
305 | ||
fc8dffd3 | 306 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 307 | |
8f553c49 | 308 | void cpus_read_lock(void) |
a9d9baa1 | 309 | { |
fc8dffd3 | 310 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 311 | } |
8f553c49 | 312 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 313 | |
6f4ceee9 WL |
314 | int cpus_read_trylock(void) |
315 | { | |
316 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
317 | } | |
318 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
319 | ||
8f553c49 | 320 | void cpus_read_unlock(void) |
a9d9baa1 | 321 | { |
fc8dffd3 | 322 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 323 | } |
8f553c49 | 324 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 325 | |
8f553c49 | 326 | void cpus_write_lock(void) |
d221938c | 327 | { |
fc8dffd3 | 328 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 329 | } |
87af9e7f | 330 | |
8f553c49 | 331 | void cpus_write_unlock(void) |
d221938c | 332 | { |
fc8dffd3 | 333 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
334 | } |
335 | ||
fc8dffd3 | 336 | void lockdep_assert_cpus_held(void) |
d221938c | 337 | { |
ce48c457 VS |
338 | /* |
339 | * We can't have hotplug operations before userspace starts running, | |
340 | * and some init codepaths will knowingly not take the hotplug lock. | |
341 | * This is all valid, so mute lockdep until it makes sense to report | |
342 | * unheld locks. | |
343 | */ | |
344 | if (system_state < SYSTEM_RUNNING) | |
345 | return; | |
346 | ||
fc8dffd3 | 347 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 348 | } |
79a6cdeb | 349 | |
43759fe5 FW |
350 | #ifdef CONFIG_LOCKDEP |
351 | int lockdep_is_cpus_held(void) | |
352 | { | |
353 | return percpu_rwsem_is_held(&cpu_hotplug_lock); | |
354 | } | |
355 | #endif | |
356 | ||
cb92173d PZ |
357 | static void lockdep_acquire_cpus_lock(void) |
358 | { | |
1751060e | 359 | rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); |
cb92173d PZ |
360 | } |
361 | ||
362 | static void lockdep_release_cpus_lock(void) | |
363 | { | |
1751060e | 364 | rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_); |
cb92173d PZ |
365 | } |
366 | ||
16e53dbf SB |
367 | /* |
368 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
369 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
370 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
371 | * hotplug path before performing hotplug operations. So acquiring that lock | |
372 | * guarantees mutual exclusion from any currently running hotplug operations. | |
373 | */ | |
374 | void cpu_hotplug_disable(void) | |
375 | { | |
376 | cpu_maps_update_begin(); | |
89af7ba5 | 377 | cpu_hotplug_disabled++; |
16e53dbf SB |
378 | cpu_maps_update_done(); |
379 | } | |
32145c46 | 380 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 381 | |
01b41159 LW |
382 | static void __cpu_hotplug_enable(void) |
383 | { | |
384 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
385 | return; | |
386 | cpu_hotplug_disabled--; | |
387 | } | |
388 | ||
16e53dbf SB |
389 | void cpu_hotplug_enable(void) |
390 | { | |
391 | cpu_maps_update_begin(); | |
01b41159 | 392 | __cpu_hotplug_enable(); |
16e53dbf SB |
393 | cpu_maps_update_done(); |
394 | } | |
32145c46 | 395 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
396 | |
397 | #else | |
398 | ||
399 | static void lockdep_acquire_cpus_lock(void) | |
400 | { | |
401 | } | |
402 | ||
403 | static void lockdep_release_cpus_lock(void) | |
404 | { | |
405 | } | |
406 | ||
b9d10be7 | 407 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 408 | |
a74cfffb TG |
409 | /* |
410 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
411 | * should override this. | |
412 | */ | |
413 | void __weak arch_smt_update(void) { } | |
414 | ||
0cc3cd21 TG |
415 | #ifdef CONFIG_HOTPLUG_SMT |
416 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 417 | |
8e1b706b | 418 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 419 | { |
e1572f1d | 420 | if (!cpu_smt_possible()) |
8e1b706b JK |
421 | return; |
422 | ||
423 | if (force) { | |
0cc3cd21 TG |
424 | pr_info("SMT: Force disabled\n"); |
425 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 426 | } else { |
d0e7d144 | 427 | pr_info("SMT: disabled\n"); |
8e1b706b | 428 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 429 | } |
8e1b706b JK |
430 | } |
431 | ||
fee0aede TG |
432 | /* |
433 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 434 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
435 | */ |
436 | void __init cpu_smt_check_topology(void) | |
437 | { | |
b284909a | 438 | if (!topology_smt_supported()) |
bc2d8d26 TG |
439 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
440 | } | |
441 | ||
8e1b706b JK |
442 | static int __init smt_cmdline_disable(char *str) |
443 | { | |
444 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
445 | return 0; |
446 | } | |
447 | early_param("nosmt", smt_cmdline_disable); | |
448 | ||
449 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
450 | { | |
b284909a | 451 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
452 | return true; |
453 | ||
b284909a | 454 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
455 | return true; |
456 | ||
457 | /* | |
458 | * On x86 it's required to boot all logical CPUs at least once so | |
459 | * that the init code can get a chance to set CR4.MCE on each | |
182e073f | 460 | * CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any |
0cc3cd21 TG |
461 | * core will shutdown the machine. |
462 | */ | |
e797bda3 | 463 | return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); |
0cc3cd21 | 464 | } |
e1572f1d VK |
465 | |
466 | /* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ | |
467 | bool cpu_smt_possible(void) | |
468 | { | |
469 | return cpu_smt_control != CPU_SMT_FORCE_DISABLED && | |
470 | cpu_smt_control != CPU_SMT_NOT_SUPPORTED; | |
471 | } | |
472 | EXPORT_SYMBOL_GPL(cpu_smt_possible); | |
0cc3cd21 TG |
473 | #else |
474 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
475 | #endif | |
476 | ||
4dddfb5f | 477 | static inline enum cpuhp_state |
b7ba6d8d | 478 | cpuhp_set_state(int cpu, struct cpuhp_cpu_state *st, enum cpuhp_state target) |
4dddfb5f PZ |
479 | { |
480 | enum cpuhp_state prev_state = st->state; | |
2ea46c6f | 481 | bool bringup = st->state < target; |
4dddfb5f PZ |
482 | |
483 | st->rollback = false; | |
484 | st->last = NULL; | |
485 | ||
486 | st->target = target; | |
487 | st->single = false; | |
2ea46c6f | 488 | st->bringup = bringup; |
b7ba6d8d SP |
489 | if (cpu_dying(cpu) != !bringup) |
490 | set_cpu_dying(cpu, !bringup); | |
4dddfb5f PZ |
491 | |
492 | return prev_state; | |
493 | } | |
494 | ||
495 | static inline void | |
b7ba6d8d SP |
496 | cpuhp_reset_state(int cpu, struct cpuhp_cpu_state *st, |
497 | enum cpuhp_state prev_state) | |
4dddfb5f | 498 | { |
2ea46c6f PZ |
499 | bool bringup = !st->bringup; |
500 | ||
453e4108 VD |
501 | st->target = prev_state; |
502 | ||
503 | /* | |
504 | * Already rolling back. No need invert the bringup value or to change | |
505 | * the current state. | |
506 | */ | |
507 | if (st->rollback) | |
508 | return; | |
509 | ||
4dddfb5f PZ |
510 | st->rollback = true; |
511 | ||
512 | /* | |
513 | * If we have st->last we need to undo partial multi_instance of this | |
514 | * state first. Otherwise start undo at the previous state. | |
515 | */ | |
516 | if (!st->last) { | |
517 | if (st->bringup) | |
518 | st->state--; | |
519 | else | |
520 | st->state++; | |
521 | } | |
522 | ||
2ea46c6f | 523 | st->bringup = bringup; |
b7ba6d8d SP |
524 | if (cpu_dying(cpu) != !bringup) |
525 | set_cpu_dying(cpu, !bringup); | |
4dddfb5f PZ |
526 | } |
527 | ||
528 | /* Regular hotplug invocation of the AP hotplug thread */ | |
529 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
530 | { | |
531 | if (!st->single && st->state == st->target) | |
532 | return; | |
533 | ||
534 | st->result = 0; | |
535 | /* | |
536 | * Make sure the above stores are visible before should_run becomes | |
537 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
538 | */ | |
539 | smp_mb(); | |
540 | st->should_run = true; | |
541 | wake_up_process(st->thread); | |
5ebe7742 | 542 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
543 | } |
544 | ||
b7ba6d8d SP |
545 | static int cpuhp_kick_ap(int cpu, struct cpuhp_cpu_state *st, |
546 | enum cpuhp_state target) | |
4dddfb5f PZ |
547 | { |
548 | enum cpuhp_state prev_state; | |
549 | int ret; | |
550 | ||
b7ba6d8d | 551 | prev_state = cpuhp_set_state(cpu, st, target); |
4dddfb5f PZ |
552 | __cpuhp_kick_ap(st); |
553 | if ((ret = st->result)) { | |
b7ba6d8d | 554 | cpuhp_reset_state(cpu, st, prev_state); |
4dddfb5f PZ |
555 | __cpuhp_kick_ap(st); |
556 | } | |
557 | ||
558 | return ret; | |
559 | } | |
9cd4f1a4 | 560 | |
8df3e07e TG |
561 | static int bringup_wait_for_ap(unsigned int cpu) |
562 | { | |
563 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
564 | ||
9cd4f1a4 | 565 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 566 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
567 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
568 | return -ECANCELED; | |
9cd4f1a4 | 569 | |
45178ac0 | 570 | /* Unpark the hotplug thread of the target cpu */ |
9cd4f1a4 TG |
571 | kthread_unpark(st->thread); |
572 | ||
0cc3cd21 TG |
573 | /* |
574 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
575 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 576 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
577 | * cpu_smt_allowed() check will now return false if this is not the |
578 | * primary sibling. | |
579 | */ | |
580 | if (!cpu_smt_allowed(cpu)) | |
581 | return -ECANCELED; | |
582 | ||
4dddfb5f PZ |
583 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
584 | return 0; | |
585 | ||
b7ba6d8d | 586 | return cpuhp_kick_ap(cpu, st, st->target); |
8df3e07e TG |
587 | } |
588 | ||
ba997462 TG |
589 | static int bringup_cpu(unsigned int cpu) |
590 | { | |
591 | struct task_struct *idle = idle_thread_get(cpu); | |
592 | int ret; | |
593 | ||
dce1ca05 MR |
594 | /* |
595 | * Reset stale stack state from the last time this CPU was online. | |
596 | */ | |
597 | scs_task_reset(idle); | |
598 | kasan_unpoison_task_stack(idle); | |
599 | ||
aa877175 BO |
600 | /* |
601 | * Some architectures have to walk the irq descriptors to | |
602 | * setup the vector space for the cpu which comes online. | |
603 | * Prevent irq alloc/free across the bringup. | |
604 | */ | |
605 | irq_lock_sparse(); | |
606 | ||
ba997462 TG |
607 | /* Arch-specific enabling code. */ |
608 | ret = __cpu_up(cpu, idle); | |
aa877175 | 609 | irq_unlock_sparse(); |
530e9b76 | 610 | if (ret) |
ba997462 | 611 | return ret; |
9cd4f1a4 | 612 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
613 | } |
614 | ||
bf2c59fc PZ |
615 | static int finish_cpu(unsigned int cpu) |
616 | { | |
617 | struct task_struct *idle = idle_thread_get(cpu); | |
618 | struct mm_struct *mm = idle->active_mm; | |
619 | ||
620 | /* | |
621 | * idle_task_exit() will have switched to &init_mm, now | |
622 | * clean up any remaining active_mm state. | |
623 | */ | |
624 | if (mm != &init_mm) | |
625 | idle->active_mm = &init_mm; | |
626 | mmdrop(mm); | |
627 | return 0; | |
628 | } | |
629 | ||
2e1a3483 TG |
630 | /* |
631 | * Hotplug state machine related functions | |
632 | */ | |
2e1a3483 | 633 | |
453e4108 VD |
634 | /* |
635 | * Get the next state to run. Empty ones will be skipped. Returns true if a | |
636 | * state must be run. | |
637 | * | |
638 | * st->state will be modified ahead of time, to match state_to_run, as if it | |
639 | * has already ran. | |
640 | */ | |
641 | static bool cpuhp_next_state(bool bringup, | |
642 | enum cpuhp_state *state_to_run, | |
643 | struct cpuhp_cpu_state *st, | |
644 | enum cpuhp_state target) | |
2e1a3483 | 645 | { |
453e4108 VD |
646 | do { |
647 | if (bringup) { | |
648 | if (st->state >= target) | |
649 | return false; | |
650 | ||
651 | *state_to_run = ++st->state; | |
652 | } else { | |
653 | if (st->state <= target) | |
654 | return false; | |
655 | ||
656 | *state_to_run = st->state--; | |
657 | } | |
658 | ||
659 | if (!cpuhp_step_empty(bringup, cpuhp_get_step(*state_to_run))) | |
660 | break; | |
661 | } while (true); | |
662 | ||
663 | return true; | |
664 | } | |
665 | ||
666 | static int cpuhp_invoke_callback_range(bool bringup, | |
667 | unsigned int cpu, | |
668 | struct cpuhp_cpu_state *st, | |
669 | enum cpuhp_state target) | |
670 | { | |
671 | enum cpuhp_state state; | |
672 | int err = 0; | |
673 | ||
674 | while (cpuhp_next_state(bringup, &state, st, target)) { | |
675 | err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL); | |
676 | if (err) | |
677 | break; | |
678 | } | |
679 | ||
680 | return err; | |
2e1a3483 TG |
681 | } |
682 | ||
206b9235 TG |
683 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
684 | { | |
685 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
686 | return true; | |
687 | /* | |
688 | * When CPU hotplug is disabled, then taking the CPU down is not | |
689 | * possible because takedown_cpu() and the architecture and | |
690 | * subsystem specific mechanisms are not available. So the CPU | |
691 | * which would be completely unplugged again needs to stay around | |
692 | * in the current state. | |
693 | */ | |
694 | return st->state <= CPUHP_BRINGUP_CPU; | |
695 | } | |
696 | ||
2e1a3483 | 697 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 698 | enum cpuhp_state target) |
2e1a3483 TG |
699 | { |
700 | enum cpuhp_state prev_state = st->state; | |
701 | int ret = 0; | |
702 | ||
453e4108 VD |
703 | ret = cpuhp_invoke_callback_range(true, cpu, st, target); |
704 | if (ret) { | |
ebca71a8 DZ |
705 | pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n", |
706 | ret, cpu, cpuhp_get_step(st->state)->name, | |
707 | st->state); | |
708 | ||
b7ba6d8d | 709 | cpuhp_reset_state(cpu, st, prev_state); |
453e4108 VD |
710 | if (can_rollback_cpu(st)) |
711 | WARN_ON(cpuhp_invoke_callback_range(false, cpu, st, | |
712 | prev_state)); | |
2e1a3483 TG |
713 | } |
714 | return ret; | |
715 | } | |
716 | ||
4cb28ced TG |
717 | /* |
718 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
719 | */ | |
4cb28ced TG |
720 | static int cpuhp_should_run(unsigned int cpu) |
721 | { | |
722 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
723 | ||
724 | return st->should_run; | |
725 | } | |
726 | ||
4cb28ced TG |
727 | /* |
728 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
729 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
730 | * |
731 | * Each invocation of this function by the smpboot thread does a single AP | |
732 | * state callback. | |
733 | * | |
734 | * It has 3 modes of operation: | |
735 | * - single: runs st->cb_state | |
736 | * - up: runs ++st->state, while st->state < st->target | |
737 | * - down: runs st->state--, while st->state > st->target | |
738 | * | |
739 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
740 | */ |
741 | static void cpuhp_thread_fun(unsigned int cpu) | |
742 | { | |
743 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
744 | bool bringup = st->bringup; |
745 | enum cpuhp_state state; | |
4cb28ced | 746 | |
f8b7530a NU |
747 | if (WARN_ON_ONCE(!st->should_run)) |
748 | return; | |
749 | ||
4cb28ced | 750 | /* |
4dddfb5f PZ |
751 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
752 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
753 | */ |
754 | smp_mb(); | |
4cb28ced | 755 | |
cb92173d PZ |
756 | /* |
757 | * The BP holds the hotplug lock, but we're now running on the AP, | |
758 | * ensure that anybody asserting the lock is held, will actually find | |
759 | * it so. | |
760 | */ | |
761 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 762 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 763 | |
a724632c | 764 | if (st->single) { |
4dddfb5f PZ |
765 | state = st->cb_state; |
766 | st->should_run = false; | |
767 | } else { | |
453e4108 VD |
768 | st->should_run = cpuhp_next_state(bringup, &state, st, st->target); |
769 | if (!st->should_run) | |
770 | goto end; | |
4dddfb5f PZ |
771 | } |
772 | ||
773 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
774 | ||
4dddfb5f PZ |
775 | if (cpuhp_is_atomic_state(state)) { |
776 | local_irq_disable(); | |
777 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
778 | local_irq_enable(); | |
3b9d6da6 | 779 | |
4dddfb5f PZ |
780 | /* |
781 | * STARTING/DYING must not fail! | |
782 | */ | |
783 | WARN_ON_ONCE(st->result); | |
4cb28ced | 784 | } else { |
4dddfb5f PZ |
785 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
786 | } | |
787 | ||
788 | if (st->result) { | |
789 | /* | |
790 | * If we fail on a rollback, we're up a creek without no | |
791 | * paddle, no way forward, no way back. We loose, thanks for | |
792 | * playing. | |
793 | */ | |
794 | WARN_ON_ONCE(st->rollback); | |
795 | st->should_run = false; | |
4cb28ced | 796 | } |
4dddfb5f | 797 | |
453e4108 | 798 | end: |
5f4b55e1 | 799 | cpuhp_lock_release(bringup); |
cb92173d | 800 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
801 | |
802 | if (!st->should_run) | |
5ebe7742 | 803 | complete_ap_thread(st, bringup); |
4cb28ced TG |
804 | } |
805 | ||
806 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 807 | static int |
cf392d10 TG |
808 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
809 | struct hlist_node *node) | |
4cb28ced TG |
810 | { |
811 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 812 | int ret; |
4cb28ced TG |
813 | |
814 | if (!cpu_online(cpu)) | |
815 | return 0; | |
816 | ||
5f4b55e1 PZ |
817 | cpuhp_lock_acquire(false); |
818 | cpuhp_lock_release(false); | |
819 | ||
820 | cpuhp_lock_acquire(true); | |
821 | cpuhp_lock_release(true); | |
49dfe2a6 | 822 | |
6a4e2451 TG |
823 | /* |
824 | * If we are up and running, use the hotplug thread. For early calls | |
825 | * we invoke the thread function directly. | |
826 | */ | |
827 | if (!st->thread) | |
96abb968 | 828 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 829 | |
4dddfb5f PZ |
830 | st->rollback = false; |
831 | st->last = NULL; | |
832 | ||
833 | st->node = node; | |
834 | st->bringup = bringup; | |
4cb28ced | 835 | st->cb_state = state; |
a724632c | 836 | st->single = true; |
a724632c | 837 | |
4dddfb5f | 838 | __cpuhp_kick_ap(st); |
4cb28ced | 839 | |
4cb28ced | 840 | /* |
4dddfb5f | 841 | * If we failed and did a partial, do a rollback. |
4cb28ced | 842 | */ |
4dddfb5f PZ |
843 | if ((ret = st->result) && st->last) { |
844 | st->rollback = true; | |
845 | st->bringup = !bringup; | |
846 | ||
847 | __cpuhp_kick_ap(st); | |
848 | } | |
849 | ||
1f7c70d6 TG |
850 | /* |
851 | * Clean up the leftovers so the next hotplug operation wont use stale | |
852 | * data. | |
853 | */ | |
854 | st->node = st->last = NULL; | |
4dddfb5f | 855 | return ret; |
1cf4f629 TG |
856 | } |
857 | ||
858 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
859 | { | |
860 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
861 | enum cpuhp_state prev_state = st->state; |
862 | int ret; | |
1cf4f629 | 863 | |
5f4b55e1 PZ |
864 | cpuhp_lock_acquire(false); |
865 | cpuhp_lock_release(false); | |
866 | ||
867 | cpuhp_lock_acquire(true); | |
868 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
869 | |
870 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
b7ba6d8d | 871 | ret = cpuhp_kick_ap(cpu, st, st->target); |
4dddfb5f PZ |
872 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); |
873 | ||
874 | return ret; | |
4cb28ced TG |
875 | } |
876 | ||
877 | static struct smp_hotplug_thread cpuhp_threads = { | |
878 | .store = &cpuhp_state.thread, | |
4cb28ced TG |
879 | .thread_should_run = cpuhp_should_run, |
880 | .thread_fn = cpuhp_thread_fun, | |
881 | .thread_comm = "cpuhp/%u", | |
882 | .selfparking = true, | |
883 | }; | |
884 | ||
d308077e SP |
885 | static __init void cpuhp_init_state(void) |
886 | { | |
887 | struct cpuhp_cpu_state *st; | |
888 | int cpu; | |
889 | ||
890 | for_each_possible_cpu(cpu) { | |
891 | st = per_cpu_ptr(&cpuhp_state, cpu); | |
892 | init_completion(&st->done_up); | |
893 | init_completion(&st->done_down); | |
894 | } | |
895 | } | |
896 | ||
4cb28ced TG |
897 | void __init cpuhp_threads_init(void) |
898 | { | |
d308077e | 899 | cpuhp_init_state(); |
4cb28ced TG |
900 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); |
901 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
902 | } | |
903 | ||
b22afcdf TG |
904 | /* |
905 | * | |
906 | * Serialize hotplug trainwrecks outside of the cpu_hotplug_lock | |
907 | * protected region. | |
908 | * | |
909 | * The operation is still serialized against concurrent CPU hotplug via | |
910 | * cpu_add_remove_lock, i.e. CPU map protection. But it is _not_ | |
911 | * serialized against other hotplug related activity like adding or | |
912 | * removing of state callbacks and state instances, which invoke either the | |
913 | * startup or the teardown callback of the affected state. | |
914 | * | |
915 | * This is required for subsystems which are unfixable vs. CPU hotplug and | |
916 | * evade lock inversion problems by scheduling work which has to be | |
917 | * completed _before_ cpu_up()/_cpu_down() returns. | |
918 | * | |
919 | * Don't even think about adding anything to this for any new code or even | |
920 | * drivers. It's only purpose is to keep existing lock order trainwrecks | |
921 | * working. | |
922 | * | |
923 | * For cpu_down() there might be valid reasons to finish cleanups which are | |
924 | * not required to be done under cpu_hotplug_lock, but that's a different | |
925 | * story and would be not invoked via this. | |
926 | */ | |
927 | static void cpu_up_down_serialize_trainwrecks(bool tasks_frozen) | |
928 | { | |
929 | /* | |
930 | * cpusets delegate hotplug operations to a worker to "solve" the | |
931 | * lock order problems. Wait for the worker, but only if tasks are | |
932 | * _not_ frozen (suspend, hibernate) as that would wait forever. | |
933 | * | |
934 | * The wait is required because otherwise the hotplug operation | |
935 | * returns with inconsistent state, which could even be observed in | |
936 | * user space when a new CPU is brought up. The CPU plug uevent | |
937 | * would be delivered and user space reacting on it would fail to | |
938 | * move tasks to the newly plugged CPU up to the point where the | |
939 | * work has finished because up to that point the newly plugged CPU | |
940 | * is not assignable in cpusets/cgroups. On unplug that's not | |
941 | * necessarily a visible issue, but it is still inconsistent state, | |
942 | * which is the real problem which needs to be "fixed". This can't | |
943 | * prevent the transient state between scheduling the work and | |
944 | * returning from waiting for it. | |
945 | */ | |
946 | if (!tasks_frozen) | |
947 | cpuset_wait_for_hotplug(); | |
948 | } | |
949 | ||
777c6e0d | 950 | #ifdef CONFIG_HOTPLUG_CPU |
8ff00399 NP |
951 | #ifndef arch_clear_mm_cpumask_cpu |
952 | #define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm)) | |
953 | #endif | |
954 | ||
e4cc2f87 AV |
955 | /** |
956 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
957 | * @cpu: a CPU id | |
958 | * | |
959 | * This function walks all processes, finds a valid mm struct for each one and | |
960 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
961 | * trivial, there are various non-obvious corner cases, which this function | |
962 | * tries to solve in a safe manner. | |
963 | * | |
964 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
965 | * be called only for an already offlined CPU. | |
966 | */ | |
cb79295e AV |
967 | void clear_tasks_mm_cpumask(int cpu) |
968 | { | |
969 | struct task_struct *p; | |
970 | ||
971 | /* | |
972 | * This function is called after the cpu is taken down and marked | |
973 | * offline, so its not like new tasks will ever get this cpu set in | |
974 | * their mm mask. -- Peter Zijlstra | |
975 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
976 | * full-fledged tasklist_lock. | |
977 | */ | |
e4cc2f87 | 978 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
979 | rcu_read_lock(); |
980 | for_each_process(p) { | |
981 | struct task_struct *t; | |
982 | ||
e4cc2f87 AV |
983 | /* |
984 | * Main thread might exit, but other threads may still have | |
985 | * a valid mm. Find one. | |
986 | */ | |
cb79295e AV |
987 | t = find_lock_task_mm(p); |
988 | if (!t) | |
989 | continue; | |
8ff00399 | 990 | arch_clear_mm_cpumask_cpu(cpu, t->mm); |
cb79295e AV |
991 | task_unlock(t); |
992 | } | |
993 | rcu_read_unlock(); | |
994 | } | |
995 | ||
1da177e4 | 996 | /* Take this CPU down. */ |
71cf5aee | 997 | static int take_cpu_down(void *_param) |
1da177e4 | 998 | { |
4baa0afc TG |
999 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
1000 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 1001 | int err, cpu = smp_processor_id(); |
724a8688 | 1002 | int ret; |
1da177e4 | 1003 | |
1da177e4 LT |
1004 | /* Ensure this CPU doesn't handle any more interrupts. */ |
1005 | err = __cpu_disable(); | |
1006 | if (err < 0) | |
f3705136 | 1007 | return err; |
1da177e4 | 1008 | |
a724632c | 1009 | /* |
453e4108 VD |
1010 | * Must be called from CPUHP_TEARDOWN_CPU, which means, as we are going |
1011 | * down, that the current state is CPUHP_TEARDOWN_CPU - 1. | |
a724632c | 1012 | */ |
453e4108 VD |
1013 | WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1)); |
1014 | ||
4baa0afc | 1015 | /* Invoke the former CPU_DYING callbacks */ |
453e4108 VD |
1016 | ret = cpuhp_invoke_callback_range(false, cpu, st, target); |
1017 | ||
1018 | /* | |
1019 | * DYING must not fail! | |
1020 | */ | |
1021 | WARN_ON_ONCE(ret); | |
4baa0afc | 1022 | |
52c063d1 TG |
1023 | /* Give up timekeeping duties */ |
1024 | tick_handover_do_timer(); | |
1b72d432 TG |
1025 | /* Remove CPU from timer broadcasting */ |
1026 | tick_offline_cpu(cpu); | |
14e568e7 | 1027 | /* Park the stopper thread */ |
090e77c3 | 1028 | stop_machine_park(cpu); |
f3705136 | 1029 | return 0; |
1da177e4 LT |
1030 | } |
1031 | ||
98458172 | 1032 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 1033 | { |
e69aab13 | 1034 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 1035 | int err; |
1da177e4 | 1036 | |
2a58c527 | 1037 | /* Park the smpboot threads */ |
13070833 | 1038 | kthread_park(st->thread); |
1cf4f629 | 1039 | |
6acce3ef | 1040 | /* |
a8994181 TG |
1041 | * Prevent irq alloc/free while the dying cpu reorganizes the |
1042 | * interrupt affinities. | |
6acce3ef | 1043 | */ |
a8994181 | 1044 | irq_lock_sparse(); |
6acce3ef | 1045 | |
a8994181 TG |
1046 | /* |
1047 | * So now all preempt/rcu users must observe !cpu_active(). | |
1048 | */ | |
210e2133 | 1049 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 1050 | if (err) { |
3b9d6da6 | 1051 | /* CPU refused to die */ |
a8994181 | 1052 | irq_unlock_sparse(); |
3b9d6da6 | 1053 | /* Unpark the hotplug thread so we can rollback there */ |
13070833 | 1054 | kthread_unpark(st->thread); |
98458172 | 1055 | return err; |
8fa1d7d3 | 1056 | } |
04321587 | 1057 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 1058 | |
48c5ccae | 1059 | /* |
5b1ead68 BJ |
1060 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
1061 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 1062 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
1063 | * |
1064 | * Wait for the stop thread to go away. | |
48c5ccae | 1065 | */ |
5ebe7742 | 1066 | wait_for_ap_thread(st, false); |
e69aab13 | 1067 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 1068 | |
a8994181 TG |
1069 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
1070 | irq_unlock_sparse(); | |
1071 | ||
345527b1 | 1072 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
1073 | /* This actually kills the CPU. */ |
1074 | __cpu_die(cpu); | |
1075 | ||
a49b116d | 1076 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 1077 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
1078 | return 0; |
1079 | } | |
1da177e4 | 1080 | |
71f87b2f TG |
1081 | static void cpuhp_complete_idle_dead(void *arg) |
1082 | { | |
1083 | struct cpuhp_cpu_state *st = arg; | |
1084 | ||
5ebe7742 | 1085 | complete_ap_thread(st, false); |
71f87b2f TG |
1086 | } |
1087 | ||
e69aab13 TG |
1088 | void cpuhp_report_idle_dead(void) |
1089 | { | |
1090 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
1091 | ||
1092 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 1093 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
1094 | st->state = CPUHP_AP_IDLE_DEAD; |
1095 | /* | |
1096 | * We cannot call complete after rcu_report_dead() so we delegate it | |
1097 | * to an online cpu. | |
1098 | */ | |
1099 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
1100 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
1101 | } |
1102 | ||
4dddfb5f PZ |
1103 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
1104 | enum cpuhp_state target) | |
1105 | { | |
1106 | enum cpuhp_state prev_state = st->state; | |
1107 | int ret = 0; | |
1108 | ||
453e4108 VD |
1109 | ret = cpuhp_invoke_callback_range(false, cpu, st, target); |
1110 | if (ret) { | |
ebca71a8 DZ |
1111 | pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n", |
1112 | ret, cpu, cpuhp_get_step(st->state)->name, | |
1113 | st->state); | |
453e4108 | 1114 | |
b7ba6d8d | 1115 | cpuhp_reset_state(cpu, st, prev_state); |
453e4108 VD |
1116 | |
1117 | if (st->state < prev_state) | |
1118 | WARN_ON(cpuhp_invoke_callback_range(true, cpu, st, | |
1119 | prev_state)); | |
4dddfb5f | 1120 | } |
453e4108 | 1121 | |
4dddfb5f PZ |
1122 | return ret; |
1123 | } | |
cff7d378 | 1124 | |
98458172 | 1125 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
1126 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
1127 | enum cpuhp_state target) | |
98458172 | 1128 | { |
cff7d378 TG |
1129 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
1130 | int prev_state, ret = 0; | |
98458172 TG |
1131 | |
1132 | if (num_online_cpus() == 1) | |
1133 | return -EBUSY; | |
1134 | ||
757c989b | 1135 | if (!cpu_present(cpu)) |
98458172 TG |
1136 | return -EINVAL; |
1137 | ||
8f553c49 | 1138 | cpus_write_lock(); |
98458172 TG |
1139 | |
1140 | cpuhp_tasks_frozen = tasks_frozen; | |
1141 | ||
b7ba6d8d | 1142 | prev_state = cpuhp_set_state(cpu, st, target); |
1cf4f629 TG |
1143 | /* |
1144 | * If the current CPU state is in the range of the AP hotplug thread, | |
1145 | * then we need to kick the thread. | |
1146 | */ | |
8df3e07e | 1147 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 1148 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
1149 | ret = cpuhp_kick_ap_work(cpu); |
1150 | /* | |
1151 | * The AP side has done the error rollback already. Just | |
1152 | * return the error code.. | |
1153 | */ | |
1154 | if (ret) | |
1155 | goto out; | |
1156 | ||
1157 | /* | |
1158 | * We might have stopped still in the range of the AP hotplug | |
1159 | * thread. Nothing to do anymore. | |
1160 | */ | |
8df3e07e | 1161 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1162 | goto out; |
4dddfb5f PZ |
1163 | |
1164 | st->target = target; | |
1cf4f629 TG |
1165 | } |
1166 | /* | |
8df3e07e | 1167 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1168 | * to do the further cleanups. |
1169 | */ | |
a724632c | 1170 | ret = cpuhp_down_callbacks(cpu, st, target); |
62f25069 VD |
1171 | if (ret && st->state < prev_state) { |
1172 | if (st->state == CPUHP_TEARDOWN_CPU) { | |
b7ba6d8d | 1173 | cpuhp_reset_state(cpu, st, prev_state); |
62f25069 VD |
1174 | __cpuhp_kick_ap(st); |
1175 | } else { | |
1176 | WARN(1, "DEAD callback error for CPU%d", cpu); | |
1177 | } | |
3b9d6da6 | 1178 | } |
98458172 | 1179 | |
1cf4f629 | 1180 | out: |
8f553c49 | 1181 | cpus_write_unlock(); |
941154bd TG |
1182 | /* |
1183 | * Do post unplug cleanup. This is still protected against | |
1184 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1185 | */ | |
1186 | lockup_detector_cleanup(); | |
a74cfffb | 1187 | arch_smt_update(); |
b22afcdf | 1188 | cpu_up_down_serialize_trainwrecks(tasks_frozen); |
cff7d378 | 1189 | return ret; |
e3920fb4 RW |
1190 | } |
1191 | ||
cc1fe215 TG |
1192 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1193 | { | |
bae1a962 KS |
1194 | /* |
1195 | * If the platform does not support hotplug, report it explicitly to | |
1196 | * differentiate it from a transient offlining failure. | |
1197 | */ | |
1198 | if (cc_platform_has(CC_ATTR_HOTPLUG_DISABLED)) | |
1199 | return -EOPNOTSUPP; | |
cc1fe215 TG |
1200 | if (cpu_hotplug_disabled) |
1201 | return -EBUSY; | |
1202 | return _cpu_down(cpu, 0, target); | |
1203 | } | |
1204 | ||
33c3736e | 1205 | static int cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1206 | { |
9ea09af3 | 1207 | int err; |
e3920fb4 | 1208 | |
d221938c | 1209 | cpu_maps_update_begin(); |
cc1fe215 | 1210 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1211 | cpu_maps_update_done(); |
1da177e4 LT |
1212 | return err; |
1213 | } | |
4dddfb5f | 1214 | |
33c3736e QY |
1215 | /** |
1216 | * cpu_device_down - Bring down a cpu device | |
1217 | * @dev: Pointer to the cpu device to offline | |
1218 | * | |
1219 | * This function is meant to be used by device core cpu subsystem only. | |
1220 | * | |
1221 | * Other subsystems should use remove_cpu() instead. | |
11bc021d RD |
1222 | * |
1223 | * Return: %0 on success or a negative errno code | |
33c3736e QY |
1224 | */ |
1225 | int cpu_device_down(struct device *dev) | |
af1f4045 | 1226 | { |
33c3736e | 1227 | return cpu_down(dev->id, CPUHP_OFFLINE); |
af1f4045 | 1228 | } |
4dddfb5f | 1229 | |
93ef1429 QY |
1230 | int remove_cpu(unsigned int cpu) |
1231 | { | |
1232 | int ret; | |
1233 | ||
1234 | lock_device_hotplug(); | |
1235 | ret = device_offline(get_cpu_device(cpu)); | |
1236 | unlock_device_hotplug(); | |
1237 | ||
1238 | return ret; | |
1239 | } | |
1240 | EXPORT_SYMBOL_GPL(remove_cpu); | |
1241 | ||
0441a559 QY |
1242 | void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) |
1243 | { | |
1244 | unsigned int cpu; | |
1245 | int error; | |
1246 | ||
1247 | cpu_maps_update_begin(); | |
1248 | ||
1249 | /* | |
1250 | * Make certain the cpu I'm about to reboot on is online. | |
1251 | * | |
1252 | * This is inline to what migrate_to_reboot_cpu() already do. | |
1253 | */ | |
1254 | if (!cpu_online(primary_cpu)) | |
1255 | primary_cpu = cpumask_first(cpu_online_mask); | |
1256 | ||
1257 | for_each_online_cpu(cpu) { | |
1258 | if (cpu == primary_cpu) | |
1259 | continue; | |
1260 | ||
1261 | error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
1262 | if (error) { | |
1263 | pr_err("Failed to offline CPU%d - error=%d", | |
1264 | cpu, error); | |
1265 | break; | |
1266 | } | |
1267 | } | |
1268 | ||
1269 | /* | |
1270 | * Ensure all but the reboot CPU are offline. | |
1271 | */ | |
1272 | BUG_ON(num_online_cpus() > 1); | |
1273 | ||
1274 | /* | |
1275 | * Make sure the CPUs won't be enabled by someone else after this | |
1276 | * point. Kexec will reboot to a new kernel shortly resetting | |
1277 | * everything along the way. | |
1278 | */ | |
1279 | cpu_hotplug_disabled++; | |
1280 | ||
1281 | cpu_maps_update_done(); | |
af1f4045 | 1282 | } |
4dddfb5f PZ |
1283 | |
1284 | #else | |
1285 | #define takedown_cpu NULL | |
1da177e4 LT |
1286 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1287 | ||
4baa0afc | 1288 | /** |
ee1e714b | 1289 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1290 | * @cpu: cpu that just started |
1291 | * | |
4baa0afc TG |
1292 | * It must be called by the arch code on the new cpu, before the new cpu |
1293 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1294 | */ | |
1295 | void notify_cpu_starting(unsigned int cpu) | |
1296 | { | |
1297 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1298 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1299 | int ret; |
4baa0afc | 1300 | |
0c6d4576 | 1301 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1302 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
453e4108 VD |
1303 | ret = cpuhp_invoke_callback_range(true, cpu, st, target); |
1304 | ||
1305 | /* | |
1306 | * STARTING must not fail! | |
1307 | */ | |
1308 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1309 | } |
1310 | ||
949338e3 | 1311 | /* |
9cd4f1a4 | 1312 | * Called from the idle task. Wake up the controlling task which brings the |
45178ac0 PZ |
1313 | * hotplug thread of the upcoming CPU up and then delegates the rest of the |
1314 | * online bringup to the hotplug thread. | |
949338e3 | 1315 | */ |
8df3e07e | 1316 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1317 | { |
8df3e07e | 1318 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1319 | |
1320 | /* Happens for the boot cpu */ | |
1321 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1322 | return; | |
1323 | ||
45178ac0 PZ |
1324 | /* |
1325 | * Unpart the stopper thread before we start the idle loop (and start | |
1326 | * scheduling); this ensures the stopper task is always available. | |
1327 | */ | |
1328 | stop_machine_unpark(smp_processor_id()); | |
1329 | ||
8df3e07e | 1330 | st->state = CPUHP_AP_ONLINE_IDLE; |
5ebe7742 | 1331 | complete_ap_thread(st, true); |
949338e3 TG |
1332 | } |
1333 | ||
e3920fb4 | 1334 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1335 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1336 | { |
cff7d378 | 1337 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1338 | struct task_struct *idle; |
2e1a3483 | 1339 | int ret = 0; |
1da177e4 | 1340 | |
8f553c49 | 1341 | cpus_write_lock(); |
38498a67 | 1342 | |
757c989b | 1343 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1344 | ret = -EINVAL; |
1345 | goto out; | |
1346 | } | |
1347 | ||
757c989b | 1348 | /* |
33c3736e QY |
1349 | * The caller of cpu_up() might have raced with another |
1350 | * caller. Nothing to do. | |
757c989b TG |
1351 | */ |
1352 | if (st->state >= target) | |
38498a67 | 1353 | goto out; |
757c989b TG |
1354 | |
1355 | if (st->state == CPUHP_OFFLINE) { | |
1356 | /* Let it fail before we try to bring the cpu up */ | |
1357 | idle = idle_thread_get(cpu); | |
1358 | if (IS_ERR(idle)) { | |
1359 | ret = PTR_ERR(idle); | |
1360 | goto out; | |
1361 | } | |
3bb5d2ee | 1362 | } |
38498a67 | 1363 | |
ba997462 TG |
1364 | cpuhp_tasks_frozen = tasks_frozen; |
1365 | ||
b7ba6d8d | 1366 | cpuhp_set_state(cpu, st, target); |
1cf4f629 TG |
1367 | /* |
1368 | * If the current CPU state is in the range of the AP hotplug thread, | |
1369 | * then we need to kick the thread once more. | |
1370 | */ | |
8df3e07e | 1371 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1372 | ret = cpuhp_kick_ap_work(cpu); |
1373 | /* | |
1374 | * The AP side has done the error rollback already. Just | |
1375 | * return the error code.. | |
1376 | */ | |
1377 | if (ret) | |
1378 | goto out; | |
1379 | } | |
1380 | ||
1381 | /* | |
1382 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1383 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1384 | * responsible for bringing it up to the target state. |
1385 | */ | |
8df3e07e | 1386 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1387 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1388 | out: |
8f553c49 | 1389 | cpus_write_unlock(); |
a74cfffb | 1390 | arch_smt_update(); |
b22afcdf | 1391 | cpu_up_down_serialize_trainwrecks(tasks_frozen); |
e3920fb4 RW |
1392 | return ret; |
1393 | } | |
1394 | ||
33c3736e | 1395 | static int cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1396 | { |
1397 | int err = 0; | |
cf23422b | 1398 | |
e0b582ec | 1399 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1400 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1401 | cpu); | |
87d5e023 | 1402 | #if defined(CONFIG_IA64) |
84117da5 | 1403 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1404 | #endif |
1405 | return -EINVAL; | |
1406 | } | |
e3920fb4 | 1407 | |
01b0f197 TK |
1408 | err = try_online_node(cpu_to_node(cpu)); |
1409 | if (err) | |
1410 | return err; | |
cf23422b | 1411 | |
d221938c | 1412 | cpu_maps_update_begin(); |
e761b772 MK |
1413 | |
1414 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1415 | err = -EBUSY; |
e761b772 MK |
1416 | goto out; |
1417 | } | |
05736e4a TG |
1418 | if (!cpu_smt_allowed(cpu)) { |
1419 | err = -EPERM; | |
1420 | goto out; | |
1421 | } | |
e761b772 | 1422 | |
af1f4045 | 1423 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1424 | out: |
d221938c | 1425 | cpu_maps_update_done(); |
e3920fb4 RW |
1426 | return err; |
1427 | } | |
af1f4045 | 1428 | |
33c3736e QY |
1429 | /** |
1430 | * cpu_device_up - Bring up a cpu device | |
1431 | * @dev: Pointer to the cpu device to online | |
1432 | * | |
1433 | * This function is meant to be used by device core cpu subsystem only. | |
1434 | * | |
1435 | * Other subsystems should use add_cpu() instead. | |
11bc021d RD |
1436 | * |
1437 | * Return: %0 on success or a negative errno code | |
33c3736e QY |
1438 | */ |
1439 | int cpu_device_up(struct device *dev) | |
af1f4045 | 1440 | { |
33c3736e | 1441 | return cpu_up(dev->id, CPUHP_ONLINE); |
af1f4045 | 1442 | } |
e3920fb4 | 1443 | |
93ef1429 QY |
1444 | int add_cpu(unsigned int cpu) |
1445 | { | |
1446 | int ret; | |
1447 | ||
1448 | lock_device_hotplug(); | |
1449 | ret = device_online(get_cpu_device(cpu)); | |
1450 | unlock_device_hotplug(); | |
1451 | ||
1452 | return ret; | |
1453 | } | |
1454 | EXPORT_SYMBOL_GPL(add_cpu); | |
1455 | ||
d720f986 QY |
1456 | /** |
1457 | * bringup_hibernate_cpu - Bring up the CPU that we hibernated on | |
1458 | * @sleep_cpu: The cpu we hibernated on and should be brought up. | |
1459 | * | |
1460 | * On some architectures like arm64, we can hibernate on any CPU, but on | |
1461 | * wake up the CPU we hibernated on might be offline as a side effect of | |
1462 | * using maxcpus= for example. | |
11bc021d RD |
1463 | * |
1464 | * Return: %0 on success or a negative errno code | |
d720f986 QY |
1465 | */ |
1466 | int bringup_hibernate_cpu(unsigned int sleep_cpu) | |
af1f4045 | 1467 | { |
d720f986 QY |
1468 | int ret; |
1469 | ||
1470 | if (!cpu_online(sleep_cpu)) { | |
1471 | pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); | |
33c3736e | 1472 | ret = cpu_up(sleep_cpu, CPUHP_ONLINE); |
d720f986 QY |
1473 | if (ret) { |
1474 | pr_err("Failed to bring hibernate-CPU up!\n"); | |
1475 | return ret; | |
1476 | } | |
1477 | } | |
1478 | return 0; | |
1479 | } | |
1480 | ||
b99a2659 QY |
1481 | void bringup_nonboot_cpus(unsigned int setup_max_cpus) |
1482 | { | |
1483 | unsigned int cpu; | |
1484 | ||
1485 | for_each_present_cpu(cpu) { | |
1486 | if (num_online_cpus() >= setup_max_cpus) | |
1487 | break; | |
1488 | if (!cpu_online(cpu)) | |
33c3736e | 1489 | cpu_up(cpu, CPUHP_ONLINE); |
b99a2659 | 1490 | } |
af1f4045 | 1491 | } |
e3920fb4 | 1492 | |
f3de4be9 | 1493 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1494 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1495 | |
fb7fb84a | 1496 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1497 | { |
d391e552 | 1498 | int cpu, error = 0; |
e3920fb4 | 1499 | |
d221938c | 1500 | cpu_maps_update_begin(); |
9ca12ac0 | 1501 | if (primary == -1) { |
d391e552 | 1502 | primary = cpumask_first(cpu_online_mask); |
04d4e665 FW |
1503 | if (!housekeeping_cpu(primary, HK_TYPE_TIMER)) |
1504 | primary = housekeeping_any_cpu(HK_TYPE_TIMER); | |
9ca12ac0 NP |
1505 | } else { |
1506 | if (!cpu_online(primary)) | |
1507 | primary = cpumask_first(cpu_online_mask); | |
1508 | } | |
1509 | ||
9ee349ad XF |
1510 | /* |
1511 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1512 | * with the userspace trying to use the CPU hotplug at the same time |
1513 | */ | |
e0b582ec | 1514 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1515 | |
84117da5 | 1516 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1517 | for_each_online_cpu(cpu) { |
d391e552 | 1518 | if (cpu == primary) |
e3920fb4 | 1519 | continue; |
a66d955e | 1520 | |
fb7fb84a | 1521 | if (pm_wakeup_pending()) { |
a66d955e PK |
1522 | pr_info("Wakeup pending. Abort CPU freeze\n"); |
1523 | error = -EBUSY; | |
1524 | break; | |
1525 | } | |
1526 | ||
bb3632c6 | 1527 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1528 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1529 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1530 | if (!error) |
e0b582ec | 1531 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1532 | else { |
84117da5 | 1533 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1534 | break; |
1535 | } | |
1536 | } | |
86886e55 | 1537 | |
89af7ba5 | 1538 | if (!error) |
e3920fb4 | 1539 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1540 | else |
84117da5 | 1541 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1542 | |
1543 | /* | |
1544 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
56555855 QY |
1545 | * this even in case of failure as all freeze_secondary_cpus() users are |
1546 | * supposed to do thaw_secondary_cpus() on the failure path. | |
89af7ba5 VK |
1547 | */ |
1548 | cpu_hotplug_disabled++; | |
1549 | ||
d221938c | 1550 | cpu_maps_update_done(); |
e3920fb4 RW |
1551 | return error; |
1552 | } | |
1553 | ||
56555855 | 1554 | void __weak arch_thaw_secondary_cpus_begin(void) |
d0af9eed SS |
1555 | { |
1556 | } | |
1557 | ||
56555855 | 1558 | void __weak arch_thaw_secondary_cpus_end(void) |
d0af9eed SS |
1559 | { |
1560 | } | |
1561 | ||
56555855 | 1562 | void thaw_secondary_cpus(void) |
e3920fb4 RW |
1563 | { |
1564 | int cpu, error; | |
1565 | ||
1566 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1567 | cpu_maps_update_begin(); |
01b41159 | 1568 | __cpu_hotplug_enable(); |
e0b582ec | 1569 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1570 | goto out; |
e3920fb4 | 1571 | |
84117da5 | 1572 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed | 1573 | |
56555855 | 1574 | arch_thaw_secondary_cpus_begin(); |
d0af9eed | 1575 | |
e0b582ec | 1576 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1577 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1578 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1579 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1580 | if (!error) { |
84117da5 | 1581 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1582 | continue; |
1583 | } | |
84117da5 | 1584 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1585 | } |
d0af9eed | 1586 | |
56555855 | 1587 | arch_thaw_secondary_cpus_end(); |
d0af9eed | 1588 | |
e0b582ec | 1589 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1590 | out: |
d221938c | 1591 | cpu_maps_update_done(); |
1da177e4 | 1592 | } |
e0b582ec | 1593 | |
d7268a31 | 1594 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1595 | { |
1596 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1597 | return -ENOMEM; | |
1598 | return 0; | |
1599 | } | |
1600 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1601 | |
79cfbdfa SB |
1602 | /* |
1603 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1604 | * ensure that the state of the system with respect to the tasks being frozen | |
1605 | * or not, as reported by the notification, remains unchanged *throughout the | |
1606 | * duration* of the execution of the callbacks. | |
1607 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1608 | * | |
1609 | * This synchronization is implemented by mutually excluding regular CPU | |
1610 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1611 | * Hibernate notifications. | |
1612 | */ | |
1613 | static int | |
1614 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1615 | unsigned long action, void *ptr) | |
1616 | { | |
1617 | switch (action) { | |
1618 | ||
1619 | case PM_SUSPEND_PREPARE: | |
1620 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1621 | cpu_hotplug_disable(); |
79cfbdfa SB |
1622 | break; |
1623 | ||
1624 | case PM_POST_SUSPEND: | |
1625 | case PM_POST_HIBERNATION: | |
16e53dbf | 1626 | cpu_hotplug_enable(); |
79cfbdfa SB |
1627 | break; |
1628 | ||
1629 | default: | |
1630 | return NOTIFY_DONE; | |
1631 | } | |
1632 | ||
1633 | return NOTIFY_OK; | |
1634 | } | |
1635 | ||
1636 | ||
d7268a31 | 1637 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1638 | { |
6e32d479 FY |
1639 | /* |
1640 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1641 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1642 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1643 | */ | |
79cfbdfa SB |
1644 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1645 | return 0; | |
1646 | } | |
1647 | core_initcall(cpu_hotplug_pm_sync_init); | |
1648 | ||
f3de4be9 | 1649 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1650 | |
8ce371f9 PZ |
1651 | int __boot_cpu_id; |
1652 | ||
68f4f1ec | 1653 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1654 | |
cff7d378 | 1655 | /* Boot processor state steps */ |
17a2f1ce | 1656 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1657 | [CPUHP_OFFLINE] = { |
1658 | .name = "offline", | |
3c1627e9 TG |
1659 | .startup.single = NULL, |
1660 | .teardown.single = NULL, | |
cff7d378 TG |
1661 | }, |
1662 | #ifdef CONFIG_SMP | |
1663 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1664 | .name = "threads:prepare", |
3c1627e9 TG |
1665 | .startup.single = smpboot_create_threads, |
1666 | .teardown.single = NULL, | |
757c989b | 1667 | .cant_stop = true, |
cff7d378 | 1668 | }, |
00e16c3d | 1669 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1670 | .name = "perf:prepare", |
1671 | .startup.single = perf_event_init_cpu, | |
1672 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1673 | }, |
3191dd5a JD |
1674 | [CPUHP_RANDOM_PREPARE] = { |
1675 | .name = "random:prepare", | |
1676 | .startup.single = random_prepare_cpu, | |
1677 | .teardown.single = NULL, | |
1678 | }, | |
7ee681b2 | 1679 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1680 | .name = "workqueue:prepare", |
1681 | .startup.single = workqueue_prepare_cpu, | |
1682 | .teardown.single = NULL, | |
7ee681b2 | 1683 | }, |
27590dc1 | 1684 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1685 | .name = "hrtimers:prepare", |
1686 | .startup.single = hrtimers_prepare_cpu, | |
1687 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1688 | }, |
31487f83 | 1689 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1690 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1691 | .startup.single = smpcfd_prepare_cpu, |
1692 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1693 | }, |
e6d4989a RW |
1694 | [CPUHP_RELAY_PREPARE] = { |
1695 | .name = "relay:prepare", | |
1696 | .startup.single = relay_prepare_cpu, | |
1697 | .teardown.single = NULL, | |
1698 | }, | |
6731d4f1 SAS |
1699 | [CPUHP_SLAB_PREPARE] = { |
1700 | .name = "slab:prepare", | |
1701 | .startup.single = slab_prepare_cpu, | |
1702 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1703 | }, |
4df83742 | 1704 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1705 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1706 | .startup.single = rcutree_prepare_cpu, |
1707 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1708 | }, |
4fae16df RC |
1709 | /* |
1710 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1711 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1712 | * otherwise a RCU stall occurs. | |
1713 | */ | |
26456f87 | 1714 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1715 | .name = "timers:prepare", |
26456f87 | 1716 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1717 | .teardown.single = timers_dead_cpu, |
4fae16df | 1718 | }, |
d10ef6f9 | 1719 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1720 | [CPUHP_BRINGUP_CPU] = { |
1721 | .name = "cpu:bringup", | |
3c1627e9 | 1722 | .startup.single = bringup_cpu, |
bf2c59fc | 1723 | .teardown.single = finish_cpu, |
757c989b | 1724 | .cant_stop = true, |
4baa0afc | 1725 | }, |
d10ef6f9 TG |
1726 | /* Final state before CPU kills itself */ |
1727 | [CPUHP_AP_IDLE_DEAD] = { | |
1728 | .name = "idle:dead", | |
1729 | }, | |
1730 | /* | |
1731 | * Last state before CPU enters the idle loop to die. Transient state | |
1732 | * for synchronization. | |
1733 | */ | |
1734 | [CPUHP_AP_OFFLINE] = { | |
1735 | .name = "ap:offline", | |
1736 | .cant_stop = true, | |
1737 | }, | |
9cf7243d TG |
1738 | /* First state is scheduler control. Interrupts are disabled */ |
1739 | [CPUHP_AP_SCHED_STARTING] = { | |
1740 | .name = "sched:starting", | |
3c1627e9 TG |
1741 | .startup.single = sched_cpu_starting, |
1742 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1743 | }, |
4df83742 | 1744 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1745 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1746 | .startup.single = NULL, |
1747 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1748 | }, |
46febd37 LJ |
1749 | [CPUHP_AP_SMPCFD_DYING] = { |
1750 | .name = "smpcfd:dying", | |
1751 | .startup.single = NULL, | |
1752 | .teardown.single = smpcfd_dying_cpu, | |
1753 | }, | |
d10ef6f9 TG |
1754 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1755 | * state for synchronsization */ | |
1756 | [CPUHP_AP_ONLINE] = { | |
1757 | .name = "ap:online", | |
1758 | }, | |
17a2f1ce | 1759 | /* |
1cf12e08 | 1760 | * Handled on control processor until the plugged processor manages |
17a2f1ce LJ |
1761 | * this itself. |
1762 | */ | |
1763 | [CPUHP_TEARDOWN_CPU] = { | |
1764 | .name = "cpu:teardown", | |
1765 | .startup.single = NULL, | |
1766 | .teardown.single = takedown_cpu, | |
1767 | .cant_stop = true, | |
1768 | }, | |
1cf12e08 TG |
1769 | |
1770 | [CPUHP_AP_SCHED_WAIT_EMPTY] = { | |
1771 | .name = "sched:waitempty", | |
1772 | .startup.single = NULL, | |
1773 | .teardown.single = sched_cpu_wait_empty, | |
1774 | }, | |
1775 | ||
d10ef6f9 | 1776 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1777 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1778 | .name = "smpboot/threads:online", |
3c1627e9 | 1779 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1780 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1781 | }, |
c5cb83bb TG |
1782 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1783 | .name = "irq/affinity:online", | |
1784 | .startup.single = irq_affinity_online_cpu, | |
1785 | .teardown.single = NULL, | |
1786 | }, | |
00e16c3d | 1787 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1788 | .name = "perf:online", |
1789 | .startup.single = perf_event_init_cpu, | |
1790 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1791 | }, |
9cf57731 PZ |
1792 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1793 | .name = "lockup_detector:online", | |
1794 | .startup.single = lockup_detector_online_cpu, | |
1795 | .teardown.single = lockup_detector_offline_cpu, | |
1796 | }, | |
7ee681b2 | 1797 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1798 | .name = "workqueue:online", |
1799 | .startup.single = workqueue_online_cpu, | |
1800 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1801 | }, |
3191dd5a JD |
1802 | [CPUHP_AP_RANDOM_ONLINE] = { |
1803 | .name = "random:online", | |
1804 | .startup.single = random_online_cpu, | |
1805 | .teardown.single = NULL, | |
1806 | }, | |
4df83742 | 1807 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1808 | .name = "RCU/tree:online", |
3c1627e9 TG |
1809 | .startup.single = rcutree_online_cpu, |
1810 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1811 | }, |
4baa0afc | 1812 | #endif |
d10ef6f9 TG |
1813 | /* |
1814 | * The dynamically registered state space is here | |
1815 | */ | |
1816 | ||
aaddd7d1 TG |
1817 | #ifdef CONFIG_SMP |
1818 | /* Last state is scheduler control setting the cpu active */ | |
1819 | [CPUHP_AP_ACTIVE] = { | |
1820 | .name = "sched:active", | |
3c1627e9 TG |
1821 | .startup.single = sched_cpu_activate, |
1822 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1823 | }, |
1824 | #endif | |
1825 | ||
d10ef6f9 | 1826 | /* CPU is fully up and running. */ |
4baa0afc TG |
1827 | [CPUHP_ONLINE] = { |
1828 | .name = "online", | |
3c1627e9 TG |
1829 | .startup.single = NULL, |
1830 | .teardown.single = NULL, | |
4baa0afc TG |
1831 | }, |
1832 | }; | |
1833 | ||
5b7aa87e TG |
1834 | /* Sanity check for callbacks */ |
1835 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1836 | { | |
1837 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1838 | return -EINVAL; | |
1839 | return 0; | |
1840 | } | |
1841 | ||
dc280d93 TG |
1842 | /* |
1843 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1844 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1845 | * by having no name assigned. | |
1846 | */ | |
1847 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1848 | { | |
4205e478 TG |
1849 | enum cpuhp_state i, end; |
1850 | struct cpuhp_step *step; | |
dc280d93 | 1851 | |
4205e478 TG |
1852 | switch (state) { |
1853 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1854 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1855 | end = CPUHP_AP_ONLINE_DYN_END; |
1856 | break; | |
1857 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1858 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1859 | end = CPUHP_BP_PREPARE_DYN_END; |
1860 | break; | |
1861 | default: | |
1862 | return -EINVAL; | |
1863 | } | |
1864 | ||
1865 | for (i = state; i <= end; i++, step++) { | |
1866 | if (!step->name) | |
dc280d93 TG |
1867 | return i; |
1868 | } | |
1869 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1870 | return -ENOSPC; | |
1871 | } | |
1872 | ||
1873 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1874 | int (*startup)(unsigned int cpu), | |
1875 | int (*teardown)(unsigned int cpu), | |
1876 | bool multi_instance) | |
5b7aa87e TG |
1877 | { |
1878 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1879 | struct cpuhp_step *sp; | |
dc280d93 | 1880 | int ret = 0; |
5b7aa87e | 1881 | |
0c96b273 EB |
1882 | /* |
1883 | * If name is NULL, then the state gets removed. | |
1884 | * | |
1885 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1886 | * the first allocation from these dynamic ranges, so the removal | |
1887 | * would trigger a new allocation and clear the wrong (already | |
1888 | * empty) state, leaving the callbacks of the to be cleared state | |
1889 | * dangling, which causes wreckage on the next hotplug operation. | |
1890 | */ | |
1891 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1892 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1893 | ret = cpuhp_reserve_state(state); |
1894 | if (ret < 0) | |
dc434e05 | 1895 | return ret; |
dc280d93 TG |
1896 | state = ret; |
1897 | } | |
5b7aa87e | 1898 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1899 | if (name && sp->name) |
1900 | return -EBUSY; | |
1901 | ||
3c1627e9 TG |
1902 | sp->startup.single = startup; |
1903 | sp->teardown.single = teardown; | |
5b7aa87e | 1904 | sp->name = name; |
cf392d10 TG |
1905 | sp->multi_instance = multi_instance; |
1906 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1907 | return ret; |
5b7aa87e TG |
1908 | } |
1909 | ||
1910 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1911 | { | |
3c1627e9 | 1912 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1913 | } |
1914 | ||
5b7aa87e TG |
1915 | /* |
1916 | * Call the startup/teardown function for a step either on the AP or | |
1917 | * on the current CPU. | |
1918 | */ | |
cf392d10 TG |
1919 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1920 | struct hlist_node *node) | |
5b7aa87e | 1921 | { |
a724632c | 1922 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1923 | int ret; |
1924 | ||
4dddfb5f PZ |
1925 | /* |
1926 | * If there's nothing to do, we done. | |
1927 | * Relies on the union for multi_instance. | |
1928 | */ | |
453e4108 | 1929 | if (cpuhp_step_empty(bringup, sp)) |
5b7aa87e | 1930 | return 0; |
5b7aa87e TG |
1931 | /* |
1932 | * The non AP bound callbacks can fail on bringup. On teardown | |
1933 | * e.g. module removal we crash for now. | |
1934 | */ | |
1cf4f629 TG |
1935 | #ifdef CONFIG_SMP |
1936 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1937 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1938 | else |
96abb968 | 1939 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1940 | #else |
96abb968 | 1941 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1942 | #endif |
5b7aa87e TG |
1943 | BUG_ON(ret && !bringup); |
1944 | return ret; | |
1945 | } | |
1946 | ||
1947 | /* | |
1948 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1949 | * | |
1950 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1951 | */ | |
1952 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1953 | struct hlist_node *node) |
5b7aa87e TG |
1954 | { |
1955 | int cpu; | |
1956 | ||
5b7aa87e TG |
1957 | /* Roll back the already executed steps on the other cpus */ |
1958 | for_each_present_cpu(cpu) { | |
1959 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1960 | int cpustate = st->state; | |
1961 | ||
1962 | if (cpu >= failedcpu) | |
1963 | break; | |
1964 | ||
1965 | /* Did we invoke the startup call on that cpu ? */ | |
1966 | if (cpustate >= state) | |
cf392d10 | 1967 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1968 | } |
1969 | } | |
1970 | ||
9805c673 TG |
1971 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1972 | struct hlist_node *node, | |
1973 | bool invoke) | |
cf392d10 TG |
1974 | { |
1975 | struct cpuhp_step *sp; | |
1976 | int cpu; | |
1977 | int ret; | |
1978 | ||
9805c673 TG |
1979 | lockdep_assert_cpus_held(); |
1980 | ||
cf392d10 TG |
1981 | sp = cpuhp_get_step(state); |
1982 | if (sp->multi_instance == false) | |
1983 | return -EINVAL; | |
1984 | ||
dc434e05 | 1985 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1986 | |
3c1627e9 | 1987 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1988 | goto add_node; |
1989 | ||
1990 | /* | |
1991 | * Try to call the startup callback for each present cpu | |
1992 | * depending on the hotplug state of the cpu. | |
1993 | */ | |
1994 | for_each_present_cpu(cpu) { | |
1995 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1996 | int cpustate = st->state; | |
1997 | ||
1998 | if (cpustate < state) | |
1999 | continue; | |
2000 | ||
2001 | ret = cpuhp_issue_call(cpu, state, true, node); | |
2002 | if (ret) { | |
3c1627e9 | 2003 | if (sp->teardown.multi) |
cf392d10 | 2004 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 2005 | goto unlock; |
cf392d10 TG |
2006 | } |
2007 | } | |
2008 | add_node: | |
2009 | ret = 0; | |
cf392d10 | 2010 | hlist_add_head(node, &sp->list); |
dc434e05 | 2011 | unlock: |
cf392d10 | 2012 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
2013 | return ret; |
2014 | } | |
2015 | ||
2016 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
2017 | bool invoke) | |
2018 | { | |
2019 | int ret; | |
2020 | ||
2021 | cpus_read_lock(); | |
2022 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 2023 | cpus_read_unlock(); |
cf392d10 TG |
2024 | return ret; |
2025 | } | |
2026 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
2027 | ||
5b7aa87e | 2028 | /** |
71def423 | 2029 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 | 2030 | * @state: The state to setup |
ed3cd1da | 2031 | * @name: Name of the step |
dc280d93 TG |
2032 | * @invoke: If true, the startup function is invoked for cpus where |
2033 | * cpu state >= @state | |
2034 | * @startup: startup callback function | |
2035 | * @teardown: teardown callback function | |
2036 | * @multi_instance: State is set up for multiple instances which get | |
2037 | * added afterwards. | |
5b7aa87e | 2038 | * |
71def423 | 2039 | * The caller needs to hold cpus read locked while calling this function. |
11bc021d | 2040 | * Return: |
512f0980 | 2041 | * On success: |
11bc021d | 2042 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN; |
512f0980 BO |
2043 | * 0 for all other states |
2044 | * On failure: proper (negative) error code | |
5b7aa87e | 2045 | */ |
71def423 SAS |
2046 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
2047 | const char *name, bool invoke, | |
2048 | int (*startup)(unsigned int cpu), | |
2049 | int (*teardown)(unsigned int cpu), | |
2050 | bool multi_instance) | |
5b7aa87e TG |
2051 | { |
2052 | int cpu, ret = 0; | |
b9d9d691 | 2053 | bool dynstate; |
5b7aa87e | 2054 | |
71def423 SAS |
2055 | lockdep_assert_cpus_held(); |
2056 | ||
5b7aa87e TG |
2057 | if (cpuhp_cb_check(state) || !name) |
2058 | return -EINVAL; | |
2059 | ||
dc434e05 | 2060 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 2061 | |
dc280d93 TG |
2062 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
2063 | multi_instance); | |
5b7aa87e | 2064 | |
b9d9d691 TG |
2065 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
2066 | if (ret > 0 && dynstate) { | |
2067 | state = ret; | |
2068 | ret = 0; | |
2069 | } | |
2070 | ||
dc280d93 | 2071 | if (ret || !invoke || !startup) |
5b7aa87e TG |
2072 | goto out; |
2073 | ||
2074 | /* | |
2075 | * Try to call the startup callback for each present cpu | |
2076 | * depending on the hotplug state of the cpu. | |
2077 | */ | |
2078 | for_each_present_cpu(cpu) { | |
2079 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2080 | int cpustate = st->state; | |
2081 | ||
2082 | if (cpustate < state) | |
2083 | continue; | |
2084 | ||
cf392d10 | 2085 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 2086 | if (ret) { |
a724632c | 2087 | if (teardown) |
cf392d10 TG |
2088 | cpuhp_rollback_install(cpu, state, NULL); |
2089 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
2090 | goto out; |
2091 | } | |
2092 | } | |
2093 | out: | |
dc434e05 | 2094 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
2095 | /* |
2096 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
2097 | * dynamically allocated state in case of success. | |
2098 | */ | |
b9d9d691 | 2099 | if (!ret && dynstate) |
5b7aa87e TG |
2100 | return state; |
2101 | return ret; | |
2102 | } | |
71def423 SAS |
2103 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
2104 | ||
2105 | int __cpuhp_setup_state(enum cpuhp_state state, | |
2106 | const char *name, bool invoke, | |
2107 | int (*startup)(unsigned int cpu), | |
2108 | int (*teardown)(unsigned int cpu), | |
2109 | bool multi_instance) | |
2110 | { | |
2111 | int ret; | |
2112 | ||
2113 | cpus_read_lock(); | |
2114 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
2115 | teardown, multi_instance); | |
2116 | cpus_read_unlock(); | |
2117 | return ret; | |
2118 | } | |
5b7aa87e TG |
2119 | EXPORT_SYMBOL(__cpuhp_setup_state); |
2120 | ||
cf392d10 TG |
2121 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
2122 | struct hlist_node *node, bool invoke) | |
2123 | { | |
2124 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
2125 | int cpu; | |
2126 | ||
2127 | BUG_ON(cpuhp_cb_check(state)); | |
2128 | ||
2129 | if (!sp->multi_instance) | |
2130 | return -EINVAL; | |
2131 | ||
8f553c49 | 2132 | cpus_read_lock(); |
dc434e05 SAS |
2133 | mutex_lock(&cpuhp_state_mutex); |
2134 | ||
cf392d10 TG |
2135 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
2136 | goto remove; | |
2137 | /* | |
2138 | * Call the teardown callback for each present cpu depending | |
2139 | * on the hotplug state of the cpu. This function is not | |
2140 | * allowed to fail currently! | |
2141 | */ | |
2142 | for_each_present_cpu(cpu) { | |
2143 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2144 | int cpustate = st->state; | |
2145 | ||
2146 | if (cpustate >= state) | |
2147 | cpuhp_issue_call(cpu, state, false, node); | |
2148 | } | |
2149 | ||
2150 | remove: | |
cf392d10 TG |
2151 | hlist_del(node); |
2152 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 2153 | cpus_read_unlock(); |
cf392d10 TG |
2154 | |
2155 | return 0; | |
2156 | } | |
2157 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 2158 | |
5b7aa87e | 2159 | /** |
71def423 | 2160 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
2161 | * @state: The state to remove |
2162 | * @invoke: If true, the teardown function is invoked for cpus where | |
2163 | * cpu state >= @state | |
2164 | * | |
71def423 | 2165 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
2166 | * The teardown callback is currently not allowed to fail. Think |
2167 | * about module removal! | |
2168 | */ | |
71def423 | 2169 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 2170 | { |
cf392d10 | 2171 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
2172 | int cpu; |
2173 | ||
2174 | BUG_ON(cpuhp_cb_check(state)); | |
2175 | ||
71def423 | 2176 | lockdep_assert_cpus_held(); |
5b7aa87e | 2177 | |
dc434e05 | 2178 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
2179 | if (sp->multi_instance) { |
2180 | WARN(!hlist_empty(&sp->list), | |
2181 | "Error: Removing state %d which has instances left.\n", | |
2182 | state); | |
2183 | goto remove; | |
2184 | } | |
2185 | ||
a724632c | 2186 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
2187 | goto remove; |
2188 | ||
2189 | /* | |
2190 | * Call the teardown callback for each present cpu depending | |
2191 | * on the hotplug state of the cpu. This function is not | |
2192 | * allowed to fail currently! | |
2193 | */ | |
2194 | for_each_present_cpu(cpu) { | |
2195 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2196 | int cpustate = st->state; | |
2197 | ||
2198 | if (cpustate >= state) | |
cf392d10 | 2199 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
2200 | } |
2201 | remove: | |
cf392d10 | 2202 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 2203 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
2204 | } |
2205 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
2206 | ||
2207 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
2208 | { | |
2209 | cpus_read_lock(); | |
2210 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 2211 | cpus_read_unlock(); |
5b7aa87e TG |
2212 | } |
2213 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
2214 | ||
dc8d37ed AB |
2215 | #ifdef CONFIG_HOTPLUG_SMT |
2216 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2217 | { | |
2218 | struct device *dev = get_cpu_device(cpu); | |
2219 | ||
2220 | dev->offline = true; | |
2221 | /* Tell user space about the state change */ | |
2222 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2223 | } | |
2224 | ||
2225 | static void cpuhp_online_cpu_device(unsigned int cpu) | |
2226 | { | |
2227 | struct device *dev = get_cpu_device(cpu); | |
2228 | ||
2229 | dev->offline = false; | |
2230 | /* Tell user space about the state change */ | |
2231 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2232 | } | |
2233 | ||
2234 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) | |
2235 | { | |
2236 | int cpu, ret = 0; | |
2237 | ||
2238 | cpu_maps_update_begin(); | |
2239 | for_each_online_cpu(cpu) { | |
2240 | if (topology_is_primary_thread(cpu)) | |
2241 | continue; | |
2242 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2243 | if (ret) | |
2244 | break; | |
2245 | /* | |
2246 | * As this needs to hold the cpu maps lock it's impossible | |
2247 | * to call device_offline() because that ends up calling | |
2248 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2249 | * needs to be held as this might race against in kernel | |
2250 | * abusers of the hotplug machinery (thermal management). | |
2251 | * | |
2252 | * So nothing would update device:offline state. That would | |
2253 | * leave the sysfs entry stale and prevent onlining after | |
2254 | * smt control has been changed to 'off' again. This is | |
2255 | * called under the sysfs hotplug lock, so it is properly | |
2256 | * serialized against the regular offline usage. | |
2257 | */ | |
2258 | cpuhp_offline_cpu_device(cpu); | |
2259 | } | |
2260 | if (!ret) | |
2261 | cpu_smt_control = ctrlval; | |
2262 | cpu_maps_update_done(); | |
2263 | return ret; | |
2264 | } | |
2265 | ||
2266 | int cpuhp_smt_enable(void) | |
2267 | { | |
2268 | int cpu, ret = 0; | |
2269 | ||
2270 | cpu_maps_update_begin(); | |
2271 | cpu_smt_control = CPU_SMT_ENABLED; | |
2272 | for_each_present_cpu(cpu) { | |
2273 | /* Skip online CPUs and CPUs on offline nodes */ | |
2274 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2275 | continue; | |
2276 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2277 | if (ret) | |
2278 | break; | |
2279 | /* See comment in cpuhp_smt_disable() */ | |
2280 | cpuhp_online_cpu_device(cpu); | |
2281 | } | |
2282 | cpu_maps_update_done(); | |
2283 | return ret; | |
2284 | } | |
2285 | #endif | |
2286 | ||
98f8cdce | 2287 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1782dc87 Y |
2288 | static ssize_t state_show(struct device *dev, |
2289 | struct device_attribute *attr, char *buf) | |
98f8cdce TG |
2290 | { |
2291 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2292 | ||
2293 | return sprintf(buf, "%d\n", st->state); | |
2294 | } | |
1782dc87 | 2295 | static DEVICE_ATTR_RO(state); |
98f8cdce | 2296 | |
1782dc87 Y |
2297 | static ssize_t target_store(struct device *dev, struct device_attribute *attr, |
2298 | const char *buf, size_t count) | |
757c989b TG |
2299 | { |
2300 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2301 | struct cpuhp_step *sp; | |
2302 | int target, ret; | |
2303 | ||
2304 | ret = kstrtoint(buf, 10, &target); | |
2305 | if (ret) | |
2306 | return ret; | |
2307 | ||
2308 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
2309 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
2310 | return -EINVAL; | |
2311 | #else | |
2312 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
2313 | return -EINVAL; | |
2314 | #endif | |
2315 | ||
2316 | ret = lock_device_hotplug_sysfs(); | |
2317 | if (ret) | |
2318 | return ret; | |
2319 | ||
2320 | mutex_lock(&cpuhp_state_mutex); | |
2321 | sp = cpuhp_get_step(target); | |
2322 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
2323 | mutex_unlock(&cpuhp_state_mutex); | |
2324 | if (ret) | |
40da1b11 | 2325 | goto out; |
757c989b TG |
2326 | |
2327 | if (st->state < target) | |
33c3736e | 2328 | ret = cpu_up(dev->id, target); |
757c989b | 2329 | else |
33c3736e | 2330 | ret = cpu_down(dev->id, target); |
40da1b11 | 2331 | out: |
757c989b TG |
2332 | unlock_device_hotplug(); |
2333 | return ret ? ret : count; | |
2334 | } | |
2335 | ||
1782dc87 Y |
2336 | static ssize_t target_show(struct device *dev, |
2337 | struct device_attribute *attr, char *buf) | |
98f8cdce TG |
2338 | { |
2339 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2340 | ||
2341 | return sprintf(buf, "%d\n", st->target); | |
2342 | } | |
1782dc87 | 2343 | static DEVICE_ATTR_RW(target); |
1db49484 | 2344 | |
1782dc87 Y |
2345 | static ssize_t fail_store(struct device *dev, struct device_attribute *attr, |
2346 | const char *buf, size_t count) | |
1db49484 PZ |
2347 | { |
2348 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2349 | struct cpuhp_step *sp; | |
2350 | int fail, ret; | |
2351 | ||
2352 | ret = kstrtoint(buf, 10, &fail); | |
2353 | if (ret) | |
2354 | return ret; | |
2355 | ||
3ae70c25 VD |
2356 | if (fail == CPUHP_INVALID) { |
2357 | st->fail = fail; | |
2358 | return count; | |
2359 | } | |
2360 | ||
33d4a5a7 ET |
2361 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
2362 | return -EINVAL; | |
2363 | ||
1db49484 PZ |
2364 | /* |
2365 | * Cannot fail STARTING/DYING callbacks. | |
2366 | */ | |
2367 | if (cpuhp_is_atomic_state(fail)) | |
2368 | return -EINVAL; | |
2369 | ||
62f25069 VD |
2370 | /* |
2371 | * DEAD callbacks cannot fail... | |
2372 | * ... neither can CPUHP_BRINGUP_CPU during hotunplug. The latter | |
2373 | * triggering STARTING callbacks, a failure in this state would | |
2374 | * hinder rollback. | |
2375 | */ | |
2376 | if (fail <= CPUHP_BRINGUP_CPU && st->state > CPUHP_BRINGUP_CPU) | |
2377 | return -EINVAL; | |
2378 | ||
1db49484 PZ |
2379 | /* |
2380 | * Cannot fail anything that doesn't have callbacks. | |
2381 | */ | |
2382 | mutex_lock(&cpuhp_state_mutex); | |
2383 | sp = cpuhp_get_step(fail); | |
2384 | if (!sp->startup.single && !sp->teardown.single) | |
2385 | ret = -EINVAL; | |
2386 | mutex_unlock(&cpuhp_state_mutex); | |
2387 | if (ret) | |
2388 | return ret; | |
2389 | ||
2390 | st->fail = fail; | |
2391 | ||
2392 | return count; | |
2393 | } | |
2394 | ||
1782dc87 Y |
2395 | static ssize_t fail_show(struct device *dev, |
2396 | struct device_attribute *attr, char *buf) | |
1db49484 PZ |
2397 | { |
2398 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2399 | ||
2400 | return sprintf(buf, "%d\n", st->fail); | |
2401 | } | |
2402 | ||
1782dc87 | 2403 | static DEVICE_ATTR_RW(fail); |
1db49484 | 2404 | |
98f8cdce TG |
2405 | static struct attribute *cpuhp_cpu_attrs[] = { |
2406 | &dev_attr_state.attr, | |
2407 | &dev_attr_target.attr, | |
1db49484 | 2408 | &dev_attr_fail.attr, |
98f8cdce TG |
2409 | NULL |
2410 | }; | |
2411 | ||
993647a2 | 2412 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2413 | .attrs = cpuhp_cpu_attrs, |
2414 | .name = "hotplug", | |
2415 | NULL | |
2416 | }; | |
2417 | ||
1782dc87 | 2418 | static ssize_t states_show(struct device *dev, |
98f8cdce TG |
2419 | struct device_attribute *attr, char *buf) |
2420 | { | |
2421 | ssize_t cur, res = 0; | |
2422 | int i; | |
2423 | ||
2424 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2425 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2426 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2427 | ||
2428 | if (sp->name) { | |
2429 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2430 | buf += cur; | |
2431 | res += cur; | |
2432 | } | |
2433 | } | |
2434 | mutex_unlock(&cpuhp_state_mutex); | |
2435 | return res; | |
2436 | } | |
1782dc87 | 2437 | static DEVICE_ATTR_RO(states); |
98f8cdce TG |
2438 | |
2439 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2440 | &dev_attr_states.attr, | |
2441 | NULL | |
2442 | }; | |
2443 | ||
993647a2 | 2444 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2445 | .attrs = cpuhp_cpu_root_attrs, |
2446 | .name = "hotplug", | |
2447 | NULL | |
2448 | }; | |
2449 | ||
05736e4a TG |
2450 | #ifdef CONFIG_HOTPLUG_SMT |
2451 | ||
05736e4a | 2452 | static ssize_t |
de7b77e5 JP |
2453 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2454 | const char *buf, size_t count) | |
05736e4a TG |
2455 | { |
2456 | int ctrlval, ret; | |
2457 | ||
2458 | if (sysfs_streq(buf, "on")) | |
2459 | ctrlval = CPU_SMT_ENABLED; | |
2460 | else if (sysfs_streq(buf, "off")) | |
2461 | ctrlval = CPU_SMT_DISABLED; | |
2462 | else if (sysfs_streq(buf, "forceoff")) | |
2463 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2464 | else | |
2465 | return -EINVAL; | |
2466 | ||
2467 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2468 | return -EPERM; | |
2469 | ||
2470 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2471 | return -ENODEV; | |
2472 | ||
2473 | ret = lock_device_hotplug_sysfs(); | |
2474 | if (ret) | |
2475 | return ret; | |
2476 | ||
2477 | if (ctrlval != cpu_smt_control) { | |
2478 | switch (ctrlval) { | |
2479 | case CPU_SMT_ENABLED: | |
215af549 | 2480 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2481 | break; |
2482 | case CPU_SMT_DISABLED: | |
2483 | case CPU_SMT_FORCE_DISABLED: | |
2484 | ret = cpuhp_smt_disable(ctrlval); | |
2485 | break; | |
2486 | } | |
2487 | } | |
2488 | ||
2489 | unlock_device_hotplug(); | |
2490 | return ret ? ret : count; | |
2491 | } | |
de7b77e5 JP |
2492 | |
2493 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2494 | static ssize_t | |
2495 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2496 | const char *buf, size_t count) | |
2497 | { | |
2498 | return -ENODEV; | |
2499 | } | |
2500 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2501 | ||
2502 | static const char *smt_states[] = { | |
2503 | [CPU_SMT_ENABLED] = "on", | |
2504 | [CPU_SMT_DISABLED] = "off", | |
2505 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2506 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2507 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2508 | }; | |
2509 | ||
1782dc87 Y |
2510 | static ssize_t control_show(struct device *dev, |
2511 | struct device_attribute *attr, char *buf) | |
de7b77e5 JP |
2512 | { |
2513 | const char *state = smt_states[cpu_smt_control]; | |
2514 | ||
2515 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2516 | } | |
2517 | ||
1782dc87 Y |
2518 | static ssize_t control_store(struct device *dev, struct device_attribute *attr, |
2519 | const char *buf, size_t count) | |
de7b77e5 JP |
2520 | { |
2521 | return __store_smt_control(dev, attr, buf, count); | |
2522 | } | |
1782dc87 | 2523 | static DEVICE_ATTR_RW(control); |
05736e4a | 2524 | |
1782dc87 Y |
2525 | static ssize_t active_show(struct device *dev, |
2526 | struct device_attribute *attr, char *buf) | |
05736e4a | 2527 | { |
de7b77e5 | 2528 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a | 2529 | } |
1782dc87 | 2530 | static DEVICE_ATTR_RO(active); |
05736e4a TG |
2531 | |
2532 | static struct attribute *cpuhp_smt_attrs[] = { | |
2533 | &dev_attr_control.attr, | |
2534 | &dev_attr_active.attr, | |
2535 | NULL | |
2536 | }; | |
2537 | ||
2538 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2539 | .attrs = cpuhp_smt_attrs, | |
2540 | .name = "smt", | |
2541 | NULL | |
2542 | }; | |
2543 | ||
de7b77e5 | 2544 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2545 | { |
05736e4a TG |
2546 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2547 | &cpuhp_smt_attr_group); | |
2548 | } | |
2549 | ||
98f8cdce TG |
2550 | static int __init cpuhp_sysfs_init(void) |
2551 | { | |
2552 | int cpu, ret; | |
2553 | ||
de7b77e5 | 2554 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2555 | if (ret) |
2556 | return ret; | |
2557 | ||
98f8cdce TG |
2558 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2559 | &cpuhp_cpu_root_attr_group); | |
2560 | if (ret) | |
2561 | return ret; | |
2562 | ||
2563 | for_each_possible_cpu(cpu) { | |
2564 | struct device *dev = get_cpu_device(cpu); | |
2565 | ||
2566 | if (!dev) | |
2567 | continue; | |
2568 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2569 | if (ret) | |
2570 | return ret; | |
2571 | } | |
2572 | return 0; | |
2573 | } | |
2574 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2575 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2576 | |
e56b3bc7 LT |
2577 | /* |
2578 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2579 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2580 | * | |
e0b582ec | 2581 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2582 | * mask value that has a single bit set only. |
2583 | */ | |
b8d317d1 | 2584 | |
e56b3bc7 | 2585 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2586 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2587 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2588 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2589 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2590 | |
e56b3bc7 LT |
2591 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2592 | ||
2593 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2594 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2595 | #if BITS_PER_LONG > 32 | |
2596 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2597 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2598 | #endif |
2599 | }; | |
e56b3bc7 | 2600 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2601 | |
2602 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2603 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2604 | |
2605 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2606 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2607 | = {CPU_BITS_ALL}; |
b3199c02 | 2608 | #else |
4b804c85 | 2609 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2610 | #endif |
4b804c85 | 2611 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2612 | |
4b804c85 RV |
2613 | struct cpumask __cpu_online_mask __read_mostly; |
2614 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2615 | |
4b804c85 RV |
2616 | struct cpumask __cpu_present_mask __read_mostly; |
2617 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2618 | |
4b804c85 RV |
2619 | struct cpumask __cpu_active_mask __read_mostly; |
2620 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2621 | |
e40f74c5 PZ |
2622 | struct cpumask __cpu_dying_mask __read_mostly; |
2623 | EXPORT_SYMBOL(__cpu_dying_mask); | |
2624 | ||
0c09ab96 TG |
2625 | atomic_t __num_online_cpus __read_mostly; |
2626 | EXPORT_SYMBOL(__num_online_cpus); | |
2627 | ||
3fa41520 RR |
2628 | void init_cpu_present(const struct cpumask *src) |
2629 | { | |
c4c54dd1 | 2630 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2631 | } |
2632 | ||
2633 | void init_cpu_possible(const struct cpumask *src) | |
2634 | { | |
c4c54dd1 | 2635 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2636 | } |
2637 | ||
2638 | void init_cpu_online(const struct cpumask *src) | |
2639 | { | |
c4c54dd1 | 2640 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2641 | } |
cff7d378 | 2642 | |
0c09ab96 TG |
2643 | void set_cpu_online(unsigned int cpu, bool online) |
2644 | { | |
2645 | /* | |
2646 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2647 | * function by the reboot and kexec code which invoke it from | |
2648 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2649 | * regular CPU hotplug is properly serialized. | |
2650 | * | |
2651 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2652 | * does not protect readers which are not serialized against | |
2653 | * concurrent hotplug operations. | |
2654 | */ | |
2655 | if (online) { | |
2656 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2657 | atomic_inc(&__num_online_cpus); | |
2658 | } else { | |
2659 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2660 | atomic_dec(&__num_online_cpus); | |
2661 | } | |
2662 | } | |
2663 | ||
cff7d378 TG |
2664 | /* |
2665 | * Activate the first processor. | |
2666 | */ | |
2667 | void __init boot_cpu_init(void) | |
2668 | { | |
2669 | int cpu = smp_processor_id(); | |
2670 | ||
2671 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2672 | set_cpu_online(cpu, true); | |
2673 | set_cpu_active(cpu, true); | |
2674 | set_cpu_present(cpu, true); | |
2675 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2676 | |
2677 | #ifdef CONFIG_SMP | |
2678 | __boot_cpu_id = cpu; | |
2679 | #endif | |
cff7d378 TG |
2680 | } |
2681 | ||
2682 | /* | |
2683 | * Must be called _AFTER_ setting up the per_cpu areas | |
2684 | */ | |
b5b1404d | 2685 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2686 | { |
269777aa | 2687 | #ifdef CONFIG_SMP |
e797bda3 | 2688 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2689 | #endif |
0cc3cd21 | 2690 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2691 | } |
98af8452 | 2692 | |
731dc9df TH |
2693 | /* |
2694 | * These are used for a global "mitigations=" cmdline option for toggling | |
2695 | * optional CPU mitigations. | |
2696 | */ | |
2697 | enum cpu_mitigations { | |
2698 | CPU_MITIGATIONS_OFF, | |
2699 | CPU_MITIGATIONS_AUTO, | |
2700 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2701 | }; | |
2702 | ||
2703 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2704 | CPU_MITIGATIONS_AUTO; | |
98af8452 JP |
2705 | |
2706 | static int __init mitigations_parse_cmdline(char *arg) | |
2707 | { | |
2708 | if (!strcmp(arg, "off")) | |
2709 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2710 | else if (!strcmp(arg, "auto")) | |
2711 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2712 | else if (!strcmp(arg, "auto,nosmt")) | |
2713 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2714 | else |
2715 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2716 | arg); | |
98af8452 JP |
2717 | |
2718 | return 0; | |
2719 | } | |
2720 | early_param("mitigations", mitigations_parse_cmdline); | |
731dc9df TH |
2721 | |
2722 | /* mitigations=off */ | |
2723 | bool cpu_mitigations_off(void) | |
2724 | { | |
2725 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2726 | } | |
2727 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2728 | ||
2729 | /* mitigations=auto,nosmt */ | |
2730 | bool cpu_mitigations_auto_nosmt(void) | |
2731 | { | |
2732 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2733 | } | |
2734 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |