Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* CPU control. |
2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell | |
3 | * | |
4 | * This code is licenced under the GPL. | |
5 | */ | |
bf2c59fc | 6 | #include <linux/sched/mm.h> |
1da177e4 LT |
7 | #include <linux/proc_fs.h> |
8 | #include <linux/smp.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/notifier.h> | |
3f07c014 | 11 | #include <linux/sched/signal.h> |
ef8bd77f | 12 | #include <linux/sched/hotplug.h> |
9ca12ac0 | 13 | #include <linux/sched/isolation.h> |
29930025 | 14 | #include <linux/sched/task.h> |
a74cfffb | 15 | #include <linux/sched/smt.h> |
1da177e4 LT |
16 | #include <linux/unistd.h> |
17 | #include <linux/cpu.h> | |
cb79295e AV |
18 | #include <linux/oom.h> |
19 | #include <linux/rcupdate.h> | |
9984de1a | 20 | #include <linux/export.h> |
e4cc2f87 | 21 | #include <linux/bug.h> |
1da177e4 LT |
22 | #include <linux/kthread.h> |
23 | #include <linux/stop_machine.h> | |
81615b62 | 24 | #include <linux/mutex.h> |
5a0e3ad6 | 25 | #include <linux/gfp.h> |
79cfbdfa | 26 | #include <linux/suspend.h> |
a19423b9 | 27 | #include <linux/lockdep.h> |
345527b1 | 28 | #include <linux/tick.h> |
a8994181 | 29 | #include <linux/irq.h> |
941154bd | 30 | #include <linux/nmi.h> |
4cb28ced | 31 | #include <linux/smpboot.h> |
e6d4989a | 32 | #include <linux/relay.h> |
6731d4f1 | 33 | #include <linux/slab.h> |
fc8dffd3 | 34 | #include <linux/percpu-rwsem.h> |
cff7d378 | 35 | |
bb3632c6 | 36 | #include <trace/events/power.h> |
cff7d378 TG |
37 | #define CREATE_TRACE_POINTS |
38 | #include <trace/events/cpuhp.h> | |
1da177e4 | 39 | |
38498a67 TG |
40 | #include "smpboot.h" |
41 | ||
cff7d378 TG |
42 | /** |
43 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
44 | * @state: The current cpu state | |
45 | * @target: The target state | |
4cb28ced TG |
46 | * @thread: Pointer to the hotplug thread |
47 | * @should_run: Thread should execute | |
3b9d6da6 | 48 | * @rollback: Perform a rollback |
a724632c TG |
49 | * @single: Single callback invocation |
50 | * @bringup: Single callback bringup or teardown selector | |
51 | * @cb_state: The state for a single callback (install/uninstall) | |
4cb28ced | 52 | * @result: Result of the operation |
5ebe7742 PZ |
53 | * @done_up: Signal completion to the issuer of the task for cpu-up |
54 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
55 | */ |
56 | struct cpuhp_cpu_state { | |
57 | enum cpuhp_state state; | |
58 | enum cpuhp_state target; | |
1db49484 | 59 | enum cpuhp_state fail; |
4cb28ced TG |
60 | #ifdef CONFIG_SMP |
61 | struct task_struct *thread; | |
62 | bool should_run; | |
3b9d6da6 | 63 | bool rollback; |
a724632c TG |
64 | bool single; |
65 | bool bringup; | |
cf392d10 | 66 | struct hlist_node *node; |
4dddfb5f | 67 | struct hlist_node *last; |
4cb28ced | 68 | enum cpuhp_state cb_state; |
4cb28ced | 69 | int result; |
5ebe7742 PZ |
70 | struct completion done_up; |
71 | struct completion done_down; | |
4cb28ced | 72 | #endif |
cff7d378 TG |
73 | }; |
74 | ||
1db49484 PZ |
75 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
76 | .fail = CPUHP_INVALID, | |
77 | }; | |
cff7d378 | 78 | |
e797bda3 TG |
79 | #ifdef CONFIG_SMP |
80 | cpumask_t cpus_booted_once_mask; | |
81 | #endif | |
82 | ||
49dfe2a6 | 83 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
84 | static struct lockdep_map cpuhp_state_up_map = |
85 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
86 | static struct lockdep_map cpuhp_state_down_map = | |
87 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
88 | ||
89 | ||
76dc6c09 | 90 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
91 | { |
92 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
93 | } | |
94 | ||
76dc6c09 | 95 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
96 | { |
97 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
98 | } | |
99 | #else | |
100 | ||
76dc6c09 MM |
101 | static inline void cpuhp_lock_acquire(bool bringup) { } |
102 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 103 | |
49dfe2a6 TG |
104 | #endif |
105 | ||
cff7d378 TG |
106 | /** |
107 | * cpuhp_step - Hotplug state machine step | |
108 | * @name: Name of the step | |
109 | * @startup: Startup function of the step | |
110 | * @teardown: Teardown function of the step | |
757c989b | 111 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
112 | */ |
113 | struct cpuhp_step { | |
cf392d10 TG |
114 | const char *name; |
115 | union { | |
3c1627e9 TG |
116 | int (*single)(unsigned int cpu); |
117 | int (*multi)(unsigned int cpu, | |
118 | struct hlist_node *node); | |
119 | } startup; | |
cf392d10 | 120 | union { |
3c1627e9 TG |
121 | int (*single)(unsigned int cpu); |
122 | int (*multi)(unsigned int cpu, | |
123 | struct hlist_node *node); | |
124 | } teardown; | |
cf392d10 | 125 | struct hlist_head list; |
cf392d10 TG |
126 | bool cant_stop; |
127 | bool multi_instance; | |
cff7d378 TG |
128 | }; |
129 | ||
98f8cdce | 130 | static DEFINE_MUTEX(cpuhp_state_mutex); |
17a2f1ce | 131 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 132 | |
a724632c TG |
133 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
134 | { | |
17a2f1ce | 135 | return cpuhp_hp_states + state; |
a724632c TG |
136 | } |
137 | ||
cff7d378 TG |
138 | /** |
139 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
140 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 141 | * @state: The state to do callbacks for |
a724632c | 142 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
143 | * @node: For multi-instance, do a single entry callback for install/remove |
144 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 145 | * |
cf392d10 | 146 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 147 | */ |
a724632c | 148 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
149 | bool bringup, struct hlist_node *node, |
150 | struct hlist_node **lastp) | |
cff7d378 TG |
151 | { |
152 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 153 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
154 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
155 | int (*cb)(unsigned int cpu); | |
156 | int ret, cnt; | |
157 | ||
1db49484 PZ |
158 | if (st->fail == state) { |
159 | st->fail = CPUHP_INVALID; | |
160 | ||
161 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
162 | return 0; | |
163 | ||
164 | return -EAGAIN; | |
165 | } | |
166 | ||
cf392d10 | 167 | if (!step->multi_instance) { |
96abb968 | 168 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 169 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
170 | if (!cb) |
171 | return 0; | |
a724632c | 172 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 173 | ret = cb(cpu); |
a724632c | 174 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
175 | return ret; |
176 | } | |
3c1627e9 | 177 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
178 | if (!cbm) |
179 | return 0; | |
180 | ||
181 | /* Single invocation for instance add/remove */ | |
182 | if (node) { | |
96abb968 | 183 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
184 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
185 | ret = cbm(cpu, node); | |
186 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
187 | return ret; | |
188 | } | |
189 | ||
190 | /* State transition. Invoke on all instances */ | |
191 | cnt = 0; | |
192 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
193 | if (lastp && node == *lastp) |
194 | break; | |
195 | ||
cf392d10 TG |
196 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
197 | ret = cbm(cpu, node); | |
198 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
199 | if (ret) { |
200 | if (!lastp) | |
201 | goto err; | |
202 | ||
203 | *lastp = node; | |
204 | return ret; | |
205 | } | |
cf392d10 TG |
206 | cnt++; |
207 | } | |
96abb968 PZ |
208 | if (lastp) |
209 | *lastp = NULL; | |
cf392d10 TG |
210 | return 0; |
211 | err: | |
212 | /* Rollback the instances if one failed */ | |
3c1627e9 | 213 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
214 | if (!cbm) |
215 | return ret; | |
216 | ||
217 | hlist_for_each(node, &step->list) { | |
218 | if (!cnt--) | |
219 | break; | |
724a8688 PZ |
220 | |
221 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
222 | ret = cbm(cpu, node); | |
223 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
224 | /* | |
225 | * Rollback must not fail, | |
226 | */ | |
227 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
228 | } |
229 | return ret; | |
230 | } | |
231 | ||
98a79d6a | 232 | #ifdef CONFIG_SMP |
fcb3029a AB |
233 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
234 | { | |
235 | /* | |
236 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
237 | * purposes as that state is handled explicitly in cpu_down. | |
238 | */ | |
239 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
240 | } | |
241 | ||
5ebe7742 PZ |
242 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
243 | { | |
244 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
245 | wait_for_completion(done); | |
246 | } | |
247 | ||
248 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
249 | { | |
250 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
251 | complete(done); | |
252 | } | |
253 | ||
254 | /* | |
255 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
256 | */ | |
257 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
258 | { | |
259 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
260 | } | |
261 | ||
b3199c02 | 262 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 263 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
264 | bool cpuhp_tasks_frozen; |
265 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 266 | |
79a6cdeb | 267 | /* |
93ae4f97 SB |
268 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
269 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
270 | */ |
271 | void cpu_maps_update_begin(void) | |
272 | { | |
273 | mutex_lock(&cpu_add_remove_lock); | |
274 | } | |
275 | ||
276 | void cpu_maps_update_done(void) | |
277 | { | |
278 | mutex_unlock(&cpu_add_remove_lock); | |
279 | } | |
1da177e4 | 280 | |
fc8dffd3 TG |
281 | /* |
282 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
283 | * Should always be manipulated under cpu_add_remove_lock |
284 | */ | |
285 | static int cpu_hotplug_disabled; | |
286 | ||
79a6cdeb LJ |
287 | #ifdef CONFIG_HOTPLUG_CPU |
288 | ||
fc8dffd3 | 289 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 290 | |
8f553c49 | 291 | void cpus_read_lock(void) |
a9d9baa1 | 292 | { |
fc8dffd3 | 293 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 294 | } |
8f553c49 | 295 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 296 | |
6f4ceee9 WL |
297 | int cpus_read_trylock(void) |
298 | { | |
299 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
300 | } | |
301 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
302 | ||
8f553c49 | 303 | void cpus_read_unlock(void) |
a9d9baa1 | 304 | { |
fc8dffd3 | 305 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 306 | } |
8f553c49 | 307 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 308 | |
8f553c49 | 309 | void cpus_write_lock(void) |
d221938c | 310 | { |
fc8dffd3 | 311 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 312 | } |
87af9e7f | 313 | |
8f553c49 | 314 | void cpus_write_unlock(void) |
d221938c | 315 | { |
fc8dffd3 | 316 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
317 | } |
318 | ||
fc8dffd3 | 319 | void lockdep_assert_cpus_held(void) |
d221938c | 320 | { |
ce48c457 VS |
321 | /* |
322 | * We can't have hotplug operations before userspace starts running, | |
323 | * and some init codepaths will knowingly not take the hotplug lock. | |
324 | * This is all valid, so mute lockdep until it makes sense to report | |
325 | * unheld locks. | |
326 | */ | |
327 | if (system_state < SYSTEM_RUNNING) | |
328 | return; | |
329 | ||
fc8dffd3 | 330 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 331 | } |
79a6cdeb | 332 | |
43759fe5 FW |
333 | #ifdef CONFIG_LOCKDEP |
334 | int lockdep_is_cpus_held(void) | |
335 | { | |
336 | return percpu_rwsem_is_held(&cpu_hotplug_lock); | |
337 | } | |
338 | #endif | |
339 | ||
cb92173d PZ |
340 | static void lockdep_acquire_cpus_lock(void) |
341 | { | |
1751060e | 342 | rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); |
cb92173d PZ |
343 | } |
344 | ||
345 | static void lockdep_release_cpus_lock(void) | |
346 | { | |
1751060e | 347 | rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_); |
cb92173d PZ |
348 | } |
349 | ||
16e53dbf SB |
350 | /* |
351 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
352 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
353 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
354 | * hotplug path before performing hotplug operations. So acquiring that lock | |
355 | * guarantees mutual exclusion from any currently running hotplug operations. | |
356 | */ | |
357 | void cpu_hotplug_disable(void) | |
358 | { | |
359 | cpu_maps_update_begin(); | |
89af7ba5 | 360 | cpu_hotplug_disabled++; |
16e53dbf SB |
361 | cpu_maps_update_done(); |
362 | } | |
32145c46 | 363 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 364 | |
01b41159 LW |
365 | static void __cpu_hotplug_enable(void) |
366 | { | |
367 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
368 | return; | |
369 | cpu_hotplug_disabled--; | |
370 | } | |
371 | ||
16e53dbf SB |
372 | void cpu_hotplug_enable(void) |
373 | { | |
374 | cpu_maps_update_begin(); | |
01b41159 | 375 | __cpu_hotplug_enable(); |
16e53dbf SB |
376 | cpu_maps_update_done(); |
377 | } | |
32145c46 | 378 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
cb92173d PZ |
379 | |
380 | #else | |
381 | ||
382 | static void lockdep_acquire_cpus_lock(void) | |
383 | { | |
384 | } | |
385 | ||
386 | static void lockdep_release_cpus_lock(void) | |
387 | { | |
388 | } | |
389 | ||
b9d10be7 | 390 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 391 | |
a74cfffb TG |
392 | /* |
393 | * Architectures that need SMT-specific errata handling during SMT hotplug | |
394 | * should override this. | |
395 | */ | |
396 | void __weak arch_smt_update(void) { } | |
397 | ||
0cc3cd21 TG |
398 | #ifdef CONFIG_HOTPLUG_SMT |
399 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
bc2d8d26 | 400 | |
8e1b706b | 401 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 402 | { |
e1572f1d | 403 | if (!cpu_smt_possible()) |
8e1b706b JK |
404 | return; |
405 | ||
406 | if (force) { | |
0cc3cd21 TG |
407 | pr_info("SMT: Force disabled\n"); |
408 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b | 409 | } else { |
d0e7d144 | 410 | pr_info("SMT: disabled\n"); |
8e1b706b | 411 | cpu_smt_control = CPU_SMT_DISABLED; |
0cc3cd21 | 412 | } |
8e1b706b JK |
413 | } |
414 | ||
fee0aede TG |
415 | /* |
416 | * The decision whether SMT is supported can only be done after the full | |
b284909a | 417 | * CPU identification. Called from architecture code. |
bc2d8d26 TG |
418 | */ |
419 | void __init cpu_smt_check_topology(void) | |
420 | { | |
b284909a | 421 | if (!topology_smt_supported()) |
bc2d8d26 TG |
422 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
423 | } | |
424 | ||
8e1b706b JK |
425 | static int __init smt_cmdline_disable(char *str) |
426 | { | |
427 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
428 | return 0; |
429 | } | |
430 | early_param("nosmt", smt_cmdline_disable); | |
431 | ||
432 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
433 | { | |
b284909a | 434 | if (cpu_smt_control == CPU_SMT_ENABLED) |
0cc3cd21 TG |
435 | return true; |
436 | ||
b284909a | 437 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
438 | return true; |
439 | ||
440 | /* | |
441 | * On x86 it's required to boot all logical CPUs at least once so | |
442 | * that the init code can get a chance to set CR4.MCE on each | |
182e073f | 443 | * CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any |
0cc3cd21 TG |
444 | * core will shutdown the machine. |
445 | */ | |
e797bda3 | 446 | return !cpumask_test_cpu(cpu, &cpus_booted_once_mask); |
0cc3cd21 | 447 | } |
e1572f1d VK |
448 | |
449 | /* Returns true if SMT is not supported of forcefully (irreversibly) disabled */ | |
450 | bool cpu_smt_possible(void) | |
451 | { | |
452 | return cpu_smt_control != CPU_SMT_FORCE_DISABLED && | |
453 | cpu_smt_control != CPU_SMT_NOT_SUPPORTED; | |
454 | } | |
455 | EXPORT_SYMBOL_GPL(cpu_smt_possible); | |
0cc3cd21 TG |
456 | #else |
457 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
458 | #endif | |
459 | ||
4dddfb5f PZ |
460 | static inline enum cpuhp_state |
461 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
462 | { | |
463 | enum cpuhp_state prev_state = st->state; | |
464 | ||
465 | st->rollback = false; | |
466 | st->last = NULL; | |
467 | ||
468 | st->target = target; | |
469 | st->single = false; | |
470 | st->bringup = st->state < target; | |
471 | ||
472 | return prev_state; | |
473 | } | |
474 | ||
475 | static inline void | |
476 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
477 | { | |
478 | st->rollback = true; | |
479 | ||
480 | /* | |
481 | * If we have st->last we need to undo partial multi_instance of this | |
482 | * state first. Otherwise start undo at the previous state. | |
483 | */ | |
484 | if (!st->last) { | |
485 | if (st->bringup) | |
486 | st->state--; | |
487 | else | |
488 | st->state++; | |
489 | } | |
490 | ||
491 | st->target = prev_state; | |
492 | st->bringup = !st->bringup; | |
493 | } | |
494 | ||
495 | /* Regular hotplug invocation of the AP hotplug thread */ | |
496 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
497 | { | |
498 | if (!st->single && st->state == st->target) | |
499 | return; | |
500 | ||
501 | st->result = 0; | |
502 | /* | |
503 | * Make sure the above stores are visible before should_run becomes | |
504 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
505 | */ | |
506 | smp_mb(); | |
507 | st->should_run = true; | |
508 | wake_up_process(st->thread); | |
5ebe7742 | 509 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
510 | } |
511 | ||
512 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
513 | { | |
514 | enum cpuhp_state prev_state; | |
515 | int ret; | |
516 | ||
517 | prev_state = cpuhp_set_state(st, target); | |
518 | __cpuhp_kick_ap(st); | |
519 | if ((ret = st->result)) { | |
520 | cpuhp_reset_state(st, prev_state); | |
521 | __cpuhp_kick_ap(st); | |
522 | } | |
523 | ||
524 | return ret; | |
525 | } | |
9cd4f1a4 | 526 | |
8df3e07e TG |
527 | static int bringup_wait_for_ap(unsigned int cpu) |
528 | { | |
529 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
530 | ||
9cd4f1a4 | 531 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 532 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
533 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
534 | return -ECANCELED; | |
9cd4f1a4 | 535 | |
45178ac0 | 536 | /* Unpark the hotplug thread of the target cpu */ |
9cd4f1a4 TG |
537 | kthread_unpark(st->thread); |
538 | ||
0cc3cd21 TG |
539 | /* |
540 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
541 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
f5602011 | 542 | * CPU marked itself as booted_once in notify_cpu_starting() so the |
0cc3cd21 TG |
543 | * cpu_smt_allowed() check will now return false if this is not the |
544 | * primary sibling. | |
545 | */ | |
546 | if (!cpu_smt_allowed(cpu)) | |
547 | return -ECANCELED; | |
548 | ||
4dddfb5f PZ |
549 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
550 | return 0; | |
551 | ||
552 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
553 | } |
554 | ||
ba997462 TG |
555 | static int bringup_cpu(unsigned int cpu) |
556 | { | |
557 | struct task_struct *idle = idle_thread_get(cpu); | |
558 | int ret; | |
559 | ||
aa877175 BO |
560 | /* |
561 | * Some architectures have to walk the irq descriptors to | |
562 | * setup the vector space for the cpu which comes online. | |
563 | * Prevent irq alloc/free across the bringup. | |
564 | */ | |
565 | irq_lock_sparse(); | |
566 | ||
ba997462 TG |
567 | /* Arch-specific enabling code. */ |
568 | ret = __cpu_up(cpu, idle); | |
aa877175 | 569 | irq_unlock_sparse(); |
530e9b76 | 570 | if (ret) |
ba997462 | 571 | return ret; |
9cd4f1a4 | 572 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
573 | } |
574 | ||
bf2c59fc PZ |
575 | static int finish_cpu(unsigned int cpu) |
576 | { | |
577 | struct task_struct *idle = idle_thread_get(cpu); | |
578 | struct mm_struct *mm = idle->active_mm; | |
579 | ||
580 | /* | |
581 | * idle_task_exit() will have switched to &init_mm, now | |
582 | * clean up any remaining active_mm state. | |
583 | */ | |
584 | if (mm != &init_mm) | |
585 | idle->active_mm = &init_mm; | |
586 | mmdrop(mm); | |
587 | return 0; | |
588 | } | |
589 | ||
2e1a3483 TG |
590 | /* |
591 | * Hotplug state machine related functions | |
592 | */ | |
2e1a3483 | 593 | |
a724632c | 594 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 | 595 | { |
6fb86d97 MO |
596 | for (st->state--; st->state > st->target; st->state--) |
597 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
2e1a3483 TG |
598 | } |
599 | ||
206b9235 TG |
600 | static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
601 | { | |
602 | if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) | |
603 | return true; | |
604 | /* | |
605 | * When CPU hotplug is disabled, then taking the CPU down is not | |
606 | * possible because takedown_cpu() and the architecture and | |
607 | * subsystem specific mechanisms are not available. So the CPU | |
608 | * which would be completely unplugged again needs to stay around | |
609 | * in the current state. | |
610 | */ | |
611 | return st->state <= CPUHP_BRINGUP_CPU; | |
612 | } | |
613 | ||
2e1a3483 | 614 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
a724632c | 615 | enum cpuhp_state target) |
2e1a3483 TG |
616 | { |
617 | enum cpuhp_state prev_state = st->state; | |
618 | int ret = 0; | |
619 | ||
620 | while (st->state < target) { | |
2e1a3483 | 621 | st->state++; |
96abb968 | 622 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 | 623 | if (ret) { |
206b9235 TG |
624 | if (can_rollback_cpu(st)) { |
625 | st->target = prev_state; | |
626 | undo_cpu_up(cpu, st); | |
627 | } | |
2e1a3483 TG |
628 | break; |
629 | } | |
630 | } | |
631 | return ret; | |
632 | } | |
633 | ||
4cb28ced TG |
634 | /* |
635 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
636 | */ | |
637 | static void cpuhp_create(unsigned int cpu) | |
638 | { | |
639 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
640 | ||
5ebe7742 PZ |
641 | init_completion(&st->done_up); |
642 | init_completion(&st->done_down); | |
4cb28ced TG |
643 | } |
644 | ||
645 | static int cpuhp_should_run(unsigned int cpu) | |
646 | { | |
647 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
648 | ||
649 | return st->should_run; | |
650 | } | |
651 | ||
4cb28ced TG |
652 | /* |
653 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
654 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
655 | * |
656 | * Each invocation of this function by the smpboot thread does a single AP | |
657 | * state callback. | |
658 | * | |
659 | * It has 3 modes of operation: | |
660 | * - single: runs st->cb_state | |
661 | * - up: runs ++st->state, while st->state < st->target | |
662 | * - down: runs st->state--, while st->state > st->target | |
663 | * | |
664 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
665 | */ |
666 | static void cpuhp_thread_fun(unsigned int cpu) | |
667 | { | |
668 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
669 | bool bringup = st->bringup; |
670 | enum cpuhp_state state; | |
4cb28ced | 671 | |
f8b7530a NU |
672 | if (WARN_ON_ONCE(!st->should_run)) |
673 | return; | |
674 | ||
4cb28ced | 675 | /* |
4dddfb5f PZ |
676 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
677 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
678 | */ |
679 | smp_mb(); | |
4cb28ced | 680 | |
cb92173d PZ |
681 | /* |
682 | * The BP holds the hotplug lock, but we're now running on the AP, | |
683 | * ensure that anybody asserting the lock is held, will actually find | |
684 | * it so. | |
685 | */ | |
686 | lockdep_acquire_cpus_lock(); | |
5f4b55e1 | 687 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 688 | |
a724632c | 689 | if (st->single) { |
4dddfb5f PZ |
690 | state = st->cb_state; |
691 | st->should_run = false; | |
692 | } else { | |
693 | if (bringup) { | |
694 | st->state++; | |
695 | state = st->state; | |
696 | st->should_run = (st->state < st->target); | |
697 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 698 | } else { |
4dddfb5f PZ |
699 | state = st->state; |
700 | st->state--; | |
701 | st->should_run = (st->state > st->target); | |
702 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 703 | } |
4dddfb5f PZ |
704 | } |
705 | ||
706 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
707 | ||
4dddfb5f PZ |
708 | if (cpuhp_is_atomic_state(state)) { |
709 | local_irq_disable(); | |
710 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
711 | local_irq_enable(); | |
3b9d6da6 | 712 | |
4dddfb5f PZ |
713 | /* |
714 | * STARTING/DYING must not fail! | |
715 | */ | |
716 | WARN_ON_ONCE(st->result); | |
4cb28ced | 717 | } else { |
4dddfb5f PZ |
718 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
719 | } | |
720 | ||
721 | if (st->result) { | |
722 | /* | |
723 | * If we fail on a rollback, we're up a creek without no | |
724 | * paddle, no way forward, no way back. We loose, thanks for | |
725 | * playing. | |
726 | */ | |
727 | WARN_ON_ONCE(st->rollback); | |
728 | st->should_run = false; | |
4cb28ced | 729 | } |
4dddfb5f | 730 | |
5f4b55e1 | 731 | cpuhp_lock_release(bringup); |
cb92173d | 732 | lockdep_release_cpus_lock(); |
4dddfb5f PZ |
733 | |
734 | if (!st->should_run) | |
5ebe7742 | 735 | complete_ap_thread(st, bringup); |
4cb28ced TG |
736 | } |
737 | ||
738 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 739 | static int |
cf392d10 TG |
740 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
741 | struct hlist_node *node) | |
4cb28ced TG |
742 | { |
743 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 744 | int ret; |
4cb28ced TG |
745 | |
746 | if (!cpu_online(cpu)) | |
747 | return 0; | |
748 | ||
5f4b55e1 PZ |
749 | cpuhp_lock_acquire(false); |
750 | cpuhp_lock_release(false); | |
751 | ||
752 | cpuhp_lock_acquire(true); | |
753 | cpuhp_lock_release(true); | |
49dfe2a6 | 754 | |
6a4e2451 TG |
755 | /* |
756 | * If we are up and running, use the hotplug thread. For early calls | |
757 | * we invoke the thread function directly. | |
758 | */ | |
759 | if (!st->thread) | |
96abb968 | 760 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 761 | |
4dddfb5f PZ |
762 | st->rollback = false; |
763 | st->last = NULL; | |
764 | ||
765 | st->node = node; | |
766 | st->bringup = bringup; | |
4cb28ced | 767 | st->cb_state = state; |
a724632c | 768 | st->single = true; |
a724632c | 769 | |
4dddfb5f | 770 | __cpuhp_kick_ap(st); |
4cb28ced | 771 | |
4cb28ced | 772 | /* |
4dddfb5f | 773 | * If we failed and did a partial, do a rollback. |
4cb28ced | 774 | */ |
4dddfb5f PZ |
775 | if ((ret = st->result) && st->last) { |
776 | st->rollback = true; | |
777 | st->bringup = !bringup; | |
778 | ||
779 | __cpuhp_kick_ap(st); | |
780 | } | |
781 | ||
1f7c70d6 TG |
782 | /* |
783 | * Clean up the leftovers so the next hotplug operation wont use stale | |
784 | * data. | |
785 | */ | |
786 | st->node = st->last = NULL; | |
4dddfb5f | 787 | return ret; |
1cf4f629 TG |
788 | } |
789 | ||
790 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
791 | { | |
792 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
793 | enum cpuhp_state prev_state = st->state; |
794 | int ret; | |
1cf4f629 | 795 | |
5f4b55e1 PZ |
796 | cpuhp_lock_acquire(false); |
797 | cpuhp_lock_release(false); | |
798 | ||
799 | cpuhp_lock_acquire(true); | |
800 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
801 | |
802 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
803 | ret = cpuhp_kick_ap(st, st->target); | |
804 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
805 | ||
806 | return ret; | |
4cb28ced TG |
807 | } |
808 | ||
809 | static struct smp_hotplug_thread cpuhp_threads = { | |
810 | .store = &cpuhp_state.thread, | |
811 | .create = &cpuhp_create, | |
812 | .thread_should_run = cpuhp_should_run, | |
813 | .thread_fn = cpuhp_thread_fun, | |
814 | .thread_comm = "cpuhp/%u", | |
815 | .selfparking = true, | |
816 | }; | |
817 | ||
818 | void __init cpuhp_threads_init(void) | |
819 | { | |
820 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
821 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
822 | } | |
823 | ||
777c6e0d | 824 | #ifdef CONFIG_HOTPLUG_CPU |
8ff00399 NP |
825 | #ifndef arch_clear_mm_cpumask_cpu |
826 | #define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm)) | |
827 | #endif | |
828 | ||
e4cc2f87 AV |
829 | /** |
830 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
831 | * @cpu: a CPU id | |
832 | * | |
833 | * This function walks all processes, finds a valid mm struct for each one and | |
834 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
835 | * trivial, there are various non-obvious corner cases, which this function | |
836 | * tries to solve in a safe manner. | |
837 | * | |
838 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
839 | * be called only for an already offlined CPU. | |
840 | */ | |
cb79295e AV |
841 | void clear_tasks_mm_cpumask(int cpu) |
842 | { | |
843 | struct task_struct *p; | |
844 | ||
845 | /* | |
846 | * This function is called after the cpu is taken down and marked | |
847 | * offline, so its not like new tasks will ever get this cpu set in | |
848 | * their mm mask. -- Peter Zijlstra | |
849 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
850 | * full-fledged tasklist_lock. | |
851 | */ | |
e4cc2f87 | 852 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
853 | rcu_read_lock(); |
854 | for_each_process(p) { | |
855 | struct task_struct *t; | |
856 | ||
e4cc2f87 AV |
857 | /* |
858 | * Main thread might exit, but other threads may still have | |
859 | * a valid mm. Find one. | |
860 | */ | |
cb79295e AV |
861 | t = find_lock_task_mm(p); |
862 | if (!t) | |
863 | continue; | |
8ff00399 | 864 | arch_clear_mm_cpumask_cpu(cpu, t->mm); |
cb79295e AV |
865 | task_unlock(t); |
866 | } | |
867 | rcu_read_unlock(); | |
868 | } | |
869 | ||
1da177e4 | 870 | /* Take this CPU down. */ |
71cf5aee | 871 | static int take_cpu_down(void *_param) |
1da177e4 | 872 | { |
4baa0afc TG |
873 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
874 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 875 | int err, cpu = smp_processor_id(); |
724a8688 | 876 | int ret; |
1da177e4 | 877 | |
1da177e4 LT |
878 | /* Ensure this CPU doesn't handle any more interrupts. */ |
879 | err = __cpu_disable(); | |
880 | if (err < 0) | |
f3705136 | 881 | return err; |
1da177e4 | 882 | |
a724632c TG |
883 | /* |
884 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
885 | * do this step again. | |
886 | */ | |
887 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
888 | st->state--; | |
4baa0afc | 889 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
890 | for (; st->state > target; st->state--) { |
891 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
892 | /* | |
893 | * DYING must not fail! | |
894 | */ | |
895 | WARN_ON_ONCE(ret); | |
896 | } | |
4baa0afc | 897 | |
52c063d1 TG |
898 | /* Give up timekeeping duties */ |
899 | tick_handover_do_timer(); | |
1b72d432 TG |
900 | /* Remove CPU from timer broadcasting */ |
901 | tick_offline_cpu(cpu); | |
14e568e7 | 902 | /* Park the stopper thread */ |
090e77c3 | 903 | stop_machine_park(cpu); |
f3705136 | 904 | return 0; |
1da177e4 LT |
905 | } |
906 | ||
98458172 | 907 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 908 | { |
e69aab13 | 909 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 910 | int err; |
1da177e4 | 911 | |
2a58c527 | 912 | /* Park the smpboot threads */ |
1cf4f629 TG |
913 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
914 | ||
6acce3ef | 915 | /* |
a8994181 TG |
916 | * Prevent irq alloc/free while the dying cpu reorganizes the |
917 | * interrupt affinities. | |
6acce3ef | 918 | */ |
a8994181 | 919 | irq_lock_sparse(); |
6acce3ef | 920 | |
a8994181 TG |
921 | /* |
922 | * So now all preempt/rcu users must observe !cpu_active(). | |
923 | */ | |
210e2133 | 924 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 925 | if (err) { |
3b9d6da6 | 926 | /* CPU refused to die */ |
a8994181 | 927 | irq_unlock_sparse(); |
3b9d6da6 SAS |
928 | /* Unpark the hotplug thread so we can rollback there */ |
929 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 930 | return err; |
8fa1d7d3 | 931 | } |
04321587 | 932 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 933 | |
48c5ccae | 934 | /* |
5b1ead68 BJ |
935 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
936 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 937 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
938 | * |
939 | * Wait for the stop thread to go away. | |
48c5ccae | 940 | */ |
5ebe7742 | 941 | wait_for_ap_thread(st, false); |
e69aab13 | 942 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 943 | |
a8994181 TG |
944 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
945 | irq_unlock_sparse(); | |
946 | ||
345527b1 | 947 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
948 | /* This actually kills the CPU. */ |
949 | __cpu_die(cpu); | |
950 | ||
a49b116d | 951 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 952 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
953 | return 0; |
954 | } | |
1da177e4 | 955 | |
71f87b2f TG |
956 | static void cpuhp_complete_idle_dead(void *arg) |
957 | { | |
958 | struct cpuhp_cpu_state *st = arg; | |
959 | ||
5ebe7742 | 960 | complete_ap_thread(st, false); |
71f87b2f TG |
961 | } |
962 | ||
e69aab13 TG |
963 | void cpuhp_report_idle_dead(void) |
964 | { | |
965 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
966 | ||
967 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 968 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
969 | st->state = CPUHP_AP_IDLE_DEAD; |
970 | /* | |
971 | * We cannot call complete after rcu_report_dead() so we delegate it | |
972 | * to an online cpu. | |
973 | */ | |
974 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
975 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
976 | } |
977 | ||
4dddfb5f PZ |
978 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
979 | { | |
6fb86d97 MO |
980 | for (st->state++; st->state < st->target; st->state++) |
981 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
4dddfb5f PZ |
982 | } |
983 | ||
984 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
985 | enum cpuhp_state target) | |
986 | { | |
987 | enum cpuhp_state prev_state = st->state; | |
988 | int ret = 0; | |
989 | ||
990 | for (; st->state > target; st->state--) { | |
991 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
992 | if (ret) { | |
993 | st->target = prev_state; | |
69fa6eb7 TG |
994 | if (st->state < prev_state) |
995 | undo_cpu_down(cpu, st); | |
4dddfb5f PZ |
996 | break; |
997 | } | |
998 | } | |
999 | return ret; | |
1000 | } | |
cff7d378 | 1001 | |
98458172 | 1002 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
1003 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
1004 | enum cpuhp_state target) | |
98458172 | 1005 | { |
cff7d378 TG |
1006 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
1007 | int prev_state, ret = 0; | |
98458172 TG |
1008 | |
1009 | if (num_online_cpus() == 1) | |
1010 | return -EBUSY; | |
1011 | ||
757c989b | 1012 | if (!cpu_present(cpu)) |
98458172 TG |
1013 | return -EINVAL; |
1014 | ||
8f553c49 | 1015 | cpus_write_lock(); |
98458172 TG |
1016 | |
1017 | cpuhp_tasks_frozen = tasks_frozen; | |
1018 | ||
4dddfb5f | 1019 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
1020 | /* |
1021 | * If the current CPU state is in the range of the AP hotplug thread, | |
1022 | * then we need to kick the thread. | |
1023 | */ | |
8df3e07e | 1024 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 1025 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
1026 | ret = cpuhp_kick_ap_work(cpu); |
1027 | /* | |
1028 | * The AP side has done the error rollback already. Just | |
1029 | * return the error code.. | |
1030 | */ | |
1031 | if (ret) | |
1032 | goto out; | |
1033 | ||
1034 | /* | |
1035 | * We might have stopped still in the range of the AP hotplug | |
1036 | * thread. Nothing to do anymore. | |
1037 | */ | |
8df3e07e | 1038 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 1039 | goto out; |
4dddfb5f PZ |
1040 | |
1041 | st->target = target; | |
1cf4f629 TG |
1042 | } |
1043 | /* | |
8df3e07e | 1044 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
1045 | * to do the further cleanups. |
1046 | */ | |
a724632c | 1047 | ret = cpuhp_down_callbacks(cpu, st, target); |
69fa6eb7 | 1048 | if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
1049 | cpuhp_reset_state(st, prev_state); |
1050 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 1051 | } |
98458172 | 1052 | |
1cf4f629 | 1053 | out: |
8f553c49 | 1054 | cpus_write_unlock(); |
941154bd TG |
1055 | /* |
1056 | * Do post unplug cleanup. This is still protected against | |
1057 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1058 | */ | |
1059 | lockup_detector_cleanup(); | |
a74cfffb | 1060 | arch_smt_update(); |
cff7d378 | 1061 | return ret; |
e3920fb4 RW |
1062 | } |
1063 | ||
cc1fe215 TG |
1064 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1065 | { | |
1066 | if (cpu_hotplug_disabled) | |
1067 | return -EBUSY; | |
1068 | return _cpu_down(cpu, 0, target); | |
1069 | } | |
1070 | ||
33c3736e | 1071 | static int cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1072 | { |
9ea09af3 | 1073 | int err; |
e3920fb4 | 1074 | |
d221938c | 1075 | cpu_maps_update_begin(); |
cc1fe215 | 1076 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1077 | cpu_maps_update_done(); |
1da177e4 LT |
1078 | return err; |
1079 | } | |
4dddfb5f | 1080 | |
33c3736e QY |
1081 | /** |
1082 | * cpu_device_down - Bring down a cpu device | |
1083 | * @dev: Pointer to the cpu device to offline | |
1084 | * | |
1085 | * This function is meant to be used by device core cpu subsystem only. | |
1086 | * | |
1087 | * Other subsystems should use remove_cpu() instead. | |
1088 | */ | |
1089 | int cpu_device_down(struct device *dev) | |
af1f4045 | 1090 | { |
33c3736e | 1091 | return cpu_down(dev->id, CPUHP_OFFLINE); |
af1f4045 | 1092 | } |
4dddfb5f | 1093 | |
93ef1429 QY |
1094 | int remove_cpu(unsigned int cpu) |
1095 | { | |
1096 | int ret; | |
1097 | ||
1098 | lock_device_hotplug(); | |
1099 | ret = device_offline(get_cpu_device(cpu)); | |
1100 | unlock_device_hotplug(); | |
1101 | ||
1102 | return ret; | |
1103 | } | |
1104 | EXPORT_SYMBOL_GPL(remove_cpu); | |
1105 | ||
0441a559 QY |
1106 | void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) |
1107 | { | |
1108 | unsigned int cpu; | |
1109 | int error; | |
1110 | ||
1111 | cpu_maps_update_begin(); | |
1112 | ||
1113 | /* | |
1114 | * Make certain the cpu I'm about to reboot on is online. | |
1115 | * | |
1116 | * This is inline to what migrate_to_reboot_cpu() already do. | |
1117 | */ | |
1118 | if (!cpu_online(primary_cpu)) | |
1119 | primary_cpu = cpumask_first(cpu_online_mask); | |
1120 | ||
1121 | for_each_online_cpu(cpu) { | |
1122 | if (cpu == primary_cpu) | |
1123 | continue; | |
1124 | ||
1125 | error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
1126 | if (error) { | |
1127 | pr_err("Failed to offline CPU%d - error=%d", | |
1128 | cpu, error); | |
1129 | break; | |
1130 | } | |
1131 | } | |
1132 | ||
1133 | /* | |
1134 | * Ensure all but the reboot CPU are offline. | |
1135 | */ | |
1136 | BUG_ON(num_online_cpus() > 1); | |
1137 | ||
1138 | /* | |
1139 | * Make sure the CPUs won't be enabled by someone else after this | |
1140 | * point. Kexec will reboot to a new kernel shortly resetting | |
1141 | * everything along the way. | |
1142 | */ | |
1143 | cpu_hotplug_disabled++; | |
1144 | ||
1145 | cpu_maps_update_done(); | |
af1f4045 | 1146 | } |
4dddfb5f PZ |
1147 | |
1148 | #else | |
1149 | #define takedown_cpu NULL | |
1da177e4 LT |
1150 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1151 | ||
4baa0afc | 1152 | /** |
ee1e714b | 1153 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1154 | * @cpu: cpu that just started |
1155 | * | |
4baa0afc TG |
1156 | * It must be called by the arch code on the new cpu, before the new cpu |
1157 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1158 | */ | |
1159 | void notify_cpu_starting(unsigned int cpu) | |
1160 | { | |
1161 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1162 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1163 | int ret; |
4baa0afc | 1164 | |
0c6d4576 | 1165 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
e797bda3 | 1166 | cpumask_set_cpu(cpu, &cpus_booted_once_mask); |
4baa0afc | 1167 | while (st->state < target) { |
4baa0afc | 1168 | st->state++; |
724a8688 PZ |
1169 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1170 | /* | |
1171 | * STARTING must not fail! | |
1172 | */ | |
1173 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1174 | } |
1175 | } | |
1176 | ||
949338e3 | 1177 | /* |
9cd4f1a4 | 1178 | * Called from the idle task. Wake up the controlling task which brings the |
45178ac0 PZ |
1179 | * hotplug thread of the upcoming CPU up and then delegates the rest of the |
1180 | * online bringup to the hotplug thread. | |
949338e3 | 1181 | */ |
8df3e07e | 1182 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1183 | { |
8df3e07e | 1184 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1185 | |
1186 | /* Happens for the boot cpu */ | |
1187 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1188 | return; | |
1189 | ||
45178ac0 PZ |
1190 | /* |
1191 | * Unpart the stopper thread before we start the idle loop (and start | |
1192 | * scheduling); this ensures the stopper task is always available. | |
1193 | */ | |
1194 | stop_machine_unpark(smp_processor_id()); | |
1195 | ||
8df3e07e | 1196 | st->state = CPUHP_AP_ONLINE_IDLE; |
5ebe7742 | 1197 | complete_ap_thread(st, true); |
949338e3 TG |
1198 | } |
1199 | ||
e3920fb4 | 1200 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1201 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1202 | { |
cff7d378 | 1203 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1204 | struct task_struct *idle; |
2e1a3483 | 1205 | int ret = 0; |
1da177e4 | 1206 | |
8f553c49 | 1207 | cpus_write_lock(); |
38498a67 | 1208 | |
757c989b | 1209 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1210 | ret = -EINVAL; |
1211 | goto out; | |
1212 | } | |
1213 | ||
757c989b | 1214 | /* |
33c3736e QY |
1215 | * The caller of cpu_up() might have raced with another |
1216 | * caller. Nothing to do. | |
757c989b TG |
1217 | */ |
1218 | if (st->state >= target) | |
38498a67 | 1219 | goto out; |
757c989b TG |
1220 | |
1221 | if (st->state == CPUHP_OFFLINE) { | |
1222 | /* Let it fail before we try to bring the cpu up */ | |
1223 | idle = idle_thread_get(cpu); | |
1224 | if (IS_ERR(idle)) { | |
1225 | ret = PTR_ERR(idle); | |
1226 | goto out; | |
1227 | } | |
3bb5d2ee | 1228 | } |
38498a67 | 1229 | |
ba997462 TG |
1230 | cpuhp_tasks_frozen = tasks_frozen; |
1231 | ||
4dddfb5f | 1232 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1233 | /* |
1234 | * If the current CPU state is in the range of the AP hotplug thread, | |
1235 | * then we need to kick the thread once more. | |
1236 | */ | |
8df3e07e | 1237 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1238 | ret = cpuhp_kick_ap_work(cpu); |
1239 | /* | |
1240 | * The AP side has done the error rollback already. Just | |
1241 | * return the error code.. | |
1242 | */ | |
1243 | if (ret) | |
1244 | goto out; | |
1245 | } | |
1246 | ||
1247 | /* | |
1248 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1249 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1250 | * responsible for bringing it up to the target state. |
1251 | */ | |
8df3e07e | 1252 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1253 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1254 | out: |
8f553c49 | 1255 | cpus_write_unlock(); |
a74cfffb | 1256 | arch_smt_update(); |
e3920fb4 RW |
1257 | return ret; |
1258 | } | |
1259 | ||
33c3736e | 1260 | static int cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1261 | { |
1262 | int err = 0; | |
cf23422b | 1263 | |
e0b582ec | 1264 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1265 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1266 | cpu); | |
87d5e023 | 1267 | #if defined(CONFIG_IA64) |
84117da5 | 1268 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1269 | #endif |
1270 | return -EINVAL; | |
1271 | } | |
e3920fb4 | 1272 | |
01b0f197 TK |
1273 | err = try_online_node(cpu_to_node(cpu)); |
1274 | if (err) | |
1275 | return err; | |
cf23422b | 1276 | |
d221938c | 1277 | cpu_maps_update_begin(); |
e761b772 MK |
1278 | |
1279 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1280 | err = -EBUSY; |
e761b772 MK |
1281 | goto out; |
1282 | } | |
05736e4a TG |
1283 | if (!cpu_smt_allowed(cpu)) { |
1284 | err = -EPERM; | |
1285 | goto out; | |
1286 | } | |
e761b772 | 1287 | |
af1f4045 | 1288 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1289 | out: |
d221938c | 1290 | cpu_maps_update_done(); |
e3920fb4 RW |
1291 | return err; |
1292 | } | |
af1f4045 | 1293 | |
33c3736e QY |
1294 | /** |
1295 | * cpu_device_up - Bring up a cpu device | |
1296 | * @dev: Pointer to the cpu device to online | |
1297 | * | |
1298 | * This function is meant to be used by device core cpu subsystem only. | |
1299 | * | |
1300 | * Other subsystems should use add_cpu() instead. | |
1301 | */ | |
1302 | int cpu_device_up(struct device *dev) | |
af1f4045 | 1303 | { |
33c3736e | 1304 | return cpu_up(dev->id, CPUHP_ONLINE); |
af1f4045 | 1305 | } |
e3920fb4 | 1306 | |
93ef1429 QY |
1307 | int add_cpu(unsigned int cpu) |
1308 | { | |
1309 | int ret; | |
1310 | ||
1311 | lock_device_hotplug(); | |
1312 | ret = device_online(get_cpu_device(cpu)); | |
1313 | unlock_device_hotplug(); | |
1314 | ||
1315 | return ret; | |
1316 | } | |
1317 | EXPORT_SYMBOL_GPL(add_cpu); | |
1318 | ||
d720f986 QY |
1319 | /** |
1320 | * bringup_hibernate_cpu - Bring up the CPU that we hibernated on | |
1321 | * @sleep_cpu: The cpu we hibernated on and should be brought up. | |
1322 | * | |
1323 | * On some architectures like arm64, we can hibernate on any CPU, but on | |
1324 | * wake up the CPU we hibernated on might be offline as a side effect of | |
1325 | * using maxcpus= for example. | |
1326 | */ | |
1327 | int bringup_hibernate_cpu(unsigned int sleep_cpu) | |
af1f4045 | 1328 | { |
d720f986 QY |
1329 | int ret; |
1330 | ||
1331 | if (!cpu_online(sleep_cpu)) { | |
1332 | pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); | |
33c3736e | 1333 | ret = cpu_up(sleep_cpu, CPUHP_ONLINE); |
d720f986 QY |
1334 | if (ret) { |
1335 | pr_err("Failed to bring hibernate-CPU up!\n"); | |
1336 | return ret; | |
1337 | } | |
1338 | } | |
1339 | return 0; | |
1340 | } | |
1341 | ||
b99a2659 QY |
1342 | void bringup_nonboot_cpus(unsigned int setup_max_cpus) |
1343 | { | |
1344 | unsigned int cpu; | |
1345 | ||
1346 | for_each_present_cpu(cpu) { | |
1347 | if (num_online_cpus() >= setup_max_cpus) | |
1348 | break; | |
1349 | if (!cpu_online(cpu)) | |
33c3736e | 1350 | cpu_up(cpu, CPUHP_ONLINE); |
b99a2659 | 1351 | } |
af1f4045 | 1352 | } |
e3920fb4 | 1353 | |
f3de4be9 | 1354 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1355 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1356 | |
fb7fb84a | 1357 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1358 | { |
d391e552 | 1359 | int cpu, error = 0; |
e3920fb4 | 1360 | |
d221938c | 1361 | cpu_maps_update_begin(); |
9ca12ac0 | 1362 | if (primary == -1) { |
d391e552 | 1363 | primary = cpumask_first(cpu_online_mask); |
9ca12ac0 NP |
1364 | if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) |
1365 | primary = housekeeping_any_cpu(HK_FLAG_TIMER); | |
1366 | } else { | |
1367 | if (!cpu_online(primary)) | |
1368 | primary = cpumask_first(cpu_online_mask); | |
1369 | } | |
1370 | ||
9ee349ad XF |
1371 | /* |
1372 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1373 | * with the userspace trying to use the CPU hotplug at the same time |
1374 | */ | |
e0b582ec | 1375 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1376 | |
84117da5 | 1377 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1378 | for_each_online_cpu(cpu) { |
d391e552 | 1379 | if (cpu == primary) |
e3920fb4 | 1380 | continue; |
a66d955e | 1381 | |
fb7fb84a | 1382 | if (pm_wakeup_pending()) { |
a66d955e PK |
1383 | pr_info("Wakeup pending. Abort CPU freeze\n"); |
1384 | error = -EBUSY; | |
1385 | break; | |
1386 | } | |
1387 | ||
bb3632c6 | 1388 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1389 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1390 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1391 | if (!error) |
e0b582ec | 1392 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1393 | else { |
84117da5 | 1394 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1395 | break; |
1396 | } | |
1397 | } | |
86886e55 | 1398 | |
89af7ba5 | 1399 | if (!error) |
e3920fb4 | 1400 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1401 | else |
84117da5 | 1402 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1403 | |
1404 | /* | |
1405 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
56555855 QY |
1406 | * this even in case of failure as all freeze_secondary_cpus() users are |
1407 | * supposed to do thaw_secondary_cpus() on the failure path. | |
89af7ba5 VK |
1408 | */ |
1409 | cpu_hotplug_disabled++; | |
1410 | ||
d221938c | 1411 | cpu_maps_update_done(); |
e3920fb4 RW |
1412 | return error; |
1413 | } | |
1414 | ||
56555855 | 1415 | void __weak arch_thaw_secondary_cpus_begin(void) |
d0af9eed SS |
1416 | { |
1417 | } | |
1418 | ||
56555855 | 1419 | void __weak arch_thaw_secondary_cpus_end(void) |
d0af9eed SS |
1420 | { |
1421 | } | |
1422 | ||
56555855 | 1423 | void thaw_secondary_cpus(void) |
e3920fb4 RW |
1424 | { |
1425 | int cpu, error; | |
1426 | ||
1427 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1428 | cpu_maps_update_begin(); |
01b41159 | 1429 | __cpu_hotplug_enable(); |
e0b582ec | 1430 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1431 | goto out; |
e3920fb4 | 1432 | |
84117da5 | 1433 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed | 1434 | |
56555855 | 1435 | arch_thaw_secondary_cpus_begin(); |
d0af9eed | 1436 | |
e0b582ec | 1437 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1438 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1439 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1440 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1441 | if (!error) { |
84117da5 | 1442 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1443 | continue; |
1444 | } | |
84117da5 | 1445 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1446 | } |
d0af9eed | 1447 | |
56555855 | 1448 | arch_thaw_secondary_cpus_end(); |
d0af9eed | 1449 | |
e0b582ec | 1450 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1451 | out: |
d221938c | 1452 | cpu_maps_update_done(); |
1da177e4 | 1453 | } |
e0b582ec | 1454 | |
d7268a31 | 1455 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1456 | { |
1457 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1458 | return -ENOMEM; | |
1459 | return 0; | |
1460 | } | |
1461 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1462 | |
79cfbdfa SB |
1463 | /* |
1464 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1465 | * ensure that the state of the system with respect to the tasks being frozen | |
1466 | * or not, as reported by the notification, remains unchanged *throughout the | |
1467 | * duration* of the execution of the callbacks. | |
1468 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1469 | * | |
1470 | * This synchronization is implemented by mutually excluding regular CPU | |
1471 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1472 | * Hibernate notifications. | |
1473 | */ | |
1474 | static int | |
1475 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1476 | unsigned long action, void *ptr) | |
1477 | { | |
1478 | switch (action) { | |
1479 | ||
1480 | case PM_SUSPEND_PREPARE: | |
1481 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1482 | cpu_hotplug_disable(); |
79cfbdfa SB |
1483 | break; |
1484 | ||
1485 | case PM_POST_SUSPEND: | |
1486 | case PM_POST_HIBERNATION: | |
16e53dbf | 1487 | cpu_hotplug_enable(); |
79cfbdfa SB |
1488 | break; |
1489 | ||
1490 | default: | |
1491 | return NOTIFY_DONE; | |
1492 | } | |
1493 | ||
1494 | return NOTIFY_OK; | |
1495 | } | |
1496 | ||
1497 | ||
d7268a31 | 1498 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1499 | { |
6e32d479 FY |
1500 | /* |
1501 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1502 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1503 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1504 | */ | |
79cfbdfa SB |
1505 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1506 | return 0; | |
1507 | } | |
1508 | core_initcall(cpu_hotplug_pm_sync_init); | |
1509 | ||
f3de4be9 | 1510 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1511 | |
8ce371f9 PZ |
1512 | int __boot_cpu_id; |
1513 | ||
68f4f1ec | 1514 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1515 | |
cff7d378 | 1516 | /* Boot processor state steps */ |
17a2f1ce | 1517 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1518 | [CPUHP_OFFLINE] = { |
1519 | .name = "offline", | |
3c1627e9 TG |
1520 | .startup.single = NULL, |
1521 | .teardown.single = NULL, | |
cff7d378 TG |
1522 | }, |
1523 | #ifdef CONFIG_SMP | |
1524 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1525 | .name = "threads:prepare", |
3c1627e9 TG |
1526 | .startup.single = smpboot_create_threads, |
1527 | .teardown.single = NULL, | |
757c989b | 1528 | .cant_stop = true, |
cff7d378 | 1529 | }, |
00e16c3d | 1530 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1531 | .name = "perf:prepare", |
1532 | .startup.single = perf_event_init_cpu, | |
1533 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1534 | }, |
7ee681b2 | 1535 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1536 | .name = "workqueue:prepare", |
1537 | .startup.single = workqueue_prepare_cpu, | |
1538 | .teardown.single = NULL, | |
7ee681b2 | 1539 | }, |
27590dc1 | 1540 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1541 | .name = "hrtimers:prepare", |
1542 | .startup.single = hrtimers_prepare_cpu, | |
1543 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1544 | }, |
31487f83 | 1545 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1546 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1547 | .startup.single = smpcfd_prepare_cpu, |
1548 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1549 | }, |
e6d4989a RW |
1550 | [CPUHP_RELAY_PREPARE] = { |
1551 | .name = "relay:prepare", | |
1552 | .startup.single = relay_prepare_cpu, | |
1553 | .teardown.single = NULL, | |
1554 | }, | |
6731d4f1 SAS |
1555 | [CPUHP_SLAB_PREPARE] = { |
1556 | .name = "slab:prepare", | |
1557 | .startup.single = slab_prepare_cpu, | |
1558 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1559 | }, |
4df83742 | 1560 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1561 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1562 | .startup.single = rcutree_prepare_cpu, |
1563 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1564 | }, |
4fae16df RC |
1565 | /* |
1566 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1567 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1568 | * otherwise a RCU stall occurs. | |
1569 | */ | |
26456f87 | 1570 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1571 | .name = "timers:prepare", |
26456f87 | 1572 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1573 | .teardown.single = timers_dead_cpu, |
4fae16df | 1574 | }, |
d10ef6f9 | 1575 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1576 | [CPUHP_BRINGUP_CPU] = { |
1577 | .name = "cpu:bringup", | |
3c1627e9 | 1578 | .startup.single = bringup_cpu, |
bf2c59fc | 1579 | .teardown.single = finish_cpu, |
757c989b | 1580 | .cant_stop = true, |
4baa0afc | 1581 | }, |
d10ef6f9 TG |
1582 | /* Final state before CPU kills itself */ |
1583 | [CPUHP_AP_IDLE_DEAD] = { | |
1584 | .name = "idle:dead", | |
1585 | }, | |
1586 | /* | |
1587 | * Last state before CPU enters the idle loop to die. Transient state | |
1588 | * for synchronization. | |
1589 | */ | |
1590 | [CPUHP_AP_OFFLINE] = { | |
1591 | .name = "ap:offline", | |
1592 | .cant_stop = true, | |
1593 | }, | |
9cf7243d TG |
1594 | /* First state is scheduler control. Interrupts are disabled */ |
1595 | [CPUHP_AP_SCHED_STARTING] = { | |
1596 | .name = "sched:starting", | |
3c1627e9 TG |
1597 | .startup.single = sched_cpu_starting, |
1598 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1599 | }, |
4df83742 | 1600 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1601 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1602 | .startup.single = NULL, |
1603 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1604 | }, |
46febd37 LJ |
1605 | [CPUHP_AP_SMPCFD_DYING] = { |
1606 | .name = "smpcfd:dying", | |
1607 | .startup.single = NULL, | |
1608 | .teardown.single = smpcfd_dying_cpu, | |
1609 | }, | |
d10ef6f9 TG |
1610 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1611 | * state for synchronsization */ | |
1612 | [CPUHP_AP_ONLINE] = { | |
1613 | .name = "ap:online", | |
1614 | }, | |
17a2f1ce | 1615 | /* |
1cf12e08 | 1616 | * Handled on control processor until the plugged processor manages |
17a2f1ce LJ |
1617 | * this itself. |
1618 | */ | |
1619 | [CPUHP_TEARDOWN_CPU] = { | |
1620 | .name = "cpu:teardown", | |
1621 | .startup.single = NULL, | |
1622 | .teardown.single = takedown_cpu, | |
1623 | .cant_stop = true, | |
1624 | }, | |
1cf12e08 TG |
1625 | |
1626 | [CPUHP_AP_SCHED_WAIT_EMPTY] = { | |
1627 | .name = "sched:waitempty", | |
1628 | .startup.single = NULL, | |
1629 | .teardown.single = sched_cpu_wait_empty, | |
1630 | }, | |
1631 | ||
d10ef6f9 | 1632 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1633 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1634 | .name = "smpboot/threads:online", |
3c1627e9 | 1635 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1636 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1637 | }, |
c5cb83bb TG |
1638 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1639 | .name = "irq/affinity:online", | |
1640 | .startup.single = irq_affinity_online_cpu, | |
1641 | .teardown.single = NULL, | |
1642 | }, | |
00e16c3d | 1643 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1644 | .name = "perf:online", |
1645 | .startup.single = perf_event_init_cpu, | |
1646 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1647 | }, |
9cf57731 PZ |
1648 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1649 | .name = "lockup_detector:online", | |
1650 | .startup.single = lockup_detector_online_cpu, | |
1651 | .teardown.single = lockup_detector_offline_cpu, | |
1652 | }, | |
7ee681b2 | 1653 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1654 | .name = "workqueue:online", |
1655 | .startup.single = workqueue_online_cpu, | |
1656 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1657 | }, |
4df83742 | 1658 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1659 | .name = "RCU/tree:online", |
3c1627e9 TG |
1660 | .startup.single = rcutree_online_cpu, |
1661 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1662 | }, |
4baa0afc | 1663 | #endif |
d10ef6f9 TG |
1664 | /* |
1665 | * The dynamically registered state space is here | |
1666 | */ | |
1667 | ||
aaddd7d1 TG |
1668 | #ifdef CONFIG_SMP |
1669 | /* Last state is scheduler control setting the cpu active */ | |
1670 | [CPUHP_AP_ACTIVE] = { | |
1671 | .name = "sched:active", | |
3c1627e9 TG |
1672 | .startup.single = sched_cpu_activate, |
1673 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1674 | }, |
1675 | #endif | |
1676 | ||
d10ef6f9 | 1677 | /* CPU is fully up and running. */ |
4baa0afc TG |
1678 | [CPUHP_ONLINE] = { |
1679 | .name = "online", | |
3c1627e9 TG |
1680 | .startup.single = NULL, |
1681 | .teardown.single = NULL, | |
4baa0afc TG |
1682 | }, |
1683 | }; | |
1684 | ||
5b7aa87e TG |
1685 | /* Sanity check for callbacks */ |
1686 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1687 | { | |
1688 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1689 | return -EINVAL; | |
1690 | return 0; | |
1691 | } | |
1692 | ||
dc280d93 TG |
1693 | /* |
1694 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1695 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1696 | * by having no name assigned. | |
1697 | */ | |
1698 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1699 | { | |
4205e478 TG |
1700 | enum cpuhp_state i, end; |
1701 | struct cpuhp_step *step; | |
dc280d93 | 1702 | |
4205e478 TG |
1703 | switch (state) { |
1704 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1705 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1706 | end = CPUHP_AP_ONLINE_DYN_END; |
1707 | break; | |
1708 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1709 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1710 | end = CPUHP_BP_PREPARE_DYN_END; |
1711 | break; | |
1712 | default: | |
1713 | return -EINVAL; | |
1714 | } | |
1715 | ||
1716 | for (i = state; i <= end; i++, step++) { | |
1717 | if (!step->name) | |
dc280d93 TG |
1718 | return i; |
1719 | } | |
1720 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1721 | return -ENOSPC; | |
1722 | } | |
1723 | ||
1724 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1725 | int (*startup)(unsigned int cpu), | |
1726 | int (*teardown)(unsigned int cpu), | |
1727 | bool multi_instance) | |
5b7aa87e TG |
1728 | { |
1729 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1730 | struct cpuhp_step *sp; | |
dc280d93 | 1731 | int ret = 0; |
5b7aa87e | 1732 | |
0c96b273 EB |
1733 | /* |
1734 | * If name is NULL, then the state gets removed. | |
1735 | * | |
1736 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1737 | * the first allocation from these dynamic ranges, so the removal | |
1738 | * would trigger a new allocation and clear the wrong (already | |
1739 | * empty) state, leaving the callbacks of the to be cleared state | |
1740 | * dangling, which causes wreckage on the next hotplug operation. | |
1741 | */ | |
1742 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1743 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1744 | ret = cpuhp_reserve_state(state); |
1745 | if (ret < 0) | |
dc434e05 | 1746 | return ret; |
dc280d93 TG |
1747 | state = ret; |
1748 | } | |
5b7aa87e | 1749 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1750 | if (name && sp->name) |
1751 | return -EBUSY; | |
1752 | ||
3c1627e9 TG |
1753 | sp->startup.single = startup; |
1754 | sp->teardown.single = teardown; | |
5b7aa87e | 1755 | sp->name = name; |
cf392d10 TG |
1756 | sp->multi_instance = multi_instance; |
1757 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1758 | return ret; |
5b7aa87e TG |
1759 | } |
1760 | ||
1761 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1762 | { | |
3c1627e9 | 1763 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1764 | } |
1765 | ||
5b7aa87e TG |
1766 | /* |
1767 | * Call the startup/teardown function for a step either on the AP or | |
1768 | * on the current CPU. | |
1769 | */ | |
cf392d10 TG |
1770 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1771 | struct hlist_node *node) | |
5b7aa87e | 1772 | { |
a724632c | 1773 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1774 | int ret; |
1775 | ||
4dddfb5f PZ |
1776 | /* |
1777 | * If there's nothing to do, we done. | |
1778 | * Relies on the union for multi_instance. | |
1779 | */ | |
3c1627e9 TG |
1780 | if ((bringup && !sp->startup.single) || |
1781 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1782 | return 0; |
5b7aa87e TG |
1783 | /* |
1784 | * The non AP bound callbacks can fail on bringup. On teardown | |
1785 | * e.g. module removal we crash for now. | |
1786 | */ | |
1cf4f629 TG |
1787 | #ifdef CONFIG_SMP |
1788 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1789 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1790 | else |
96abb968 | 1791 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1792 | #else |
96abb968 | 1793 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1794 | #endif |
5b7aa87e TG |
1795 | BUG_ON(ret && !bringup); |
1796 | return ret; | |
1797 | } | |
1798 | ||
1799 | /* | |
1800 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1801 | * | |
1802 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1803 | */ | |
1804 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1805 | struct hlist_node *node) |
5b7aa87e TG |
1806 | { |
1807 | int cpu; | |
1808 | ||
5b7aa87e TG |
1809 | /* Roll back the already executed steps on the other cpus */ |
1810 | for_each_present_cpu(cpu) { | |
1811 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1812 | int cpustate = st->state; | |
1813 | ||
1814 | if (cpu >= failedcpu) | |
1815 | break; | |
1816 | ||
1817 | /* Did we invoke the startup call on that cpu ? */ | |
1818 | if (cpustate >= state) | |
cf392d10 | 1819 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1820 | } |
1821 | } | |
1822 | ||
9805c673 TG |
1823 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1824 | struct hlist_node *node, | |
1825 | bool invoke) | |
cf392d10 TG |
1826 | { |
1827 | struct cpuhp_step *sp; | |
1828 | int cpu; | |
1829 | int ret; | |
1830 | ||
9805c673 TG |
1831 | lockdep_assert_cpus_held(); |
1832 | ||
cf392d10 TG |
1833 | sp = cpuhp_get_step(state); |
1834 | if (sp->multi_instance == false) | |
1835 | return -EINVAL; | |
1836 | ||
dc434e05 | 1837 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1838 | |
3c1627e9 | 1839 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1840 | goto add_node; |
1841 | ||
1842 | /* | |
1843 | * Try to call the startup callback for each present cpu | |
1844 | * depending on the hotplug state of the cpu. | |
1845 | */ | |
1846 | for_each_present_cpu(cpu) { | |
1847 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1848 | int cpustate = st->state; | |
1849 | ||
1850 | if (cpustate < state) | |
1851 | continue; | |
1852 | ||
1853 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1854 | if (ret) { | |
3c1627e9 | 1855 | if (sp->teardown.multi) |
cf392d10 | 1856 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1857 | goto unlock; |
cf392d10 TG |
1858 | } |
1859 | } | |
1860 | add_node: | |
1861 | ret = 0; | |
cf392d10 | 1862 | hlist_add_head(node, &sp->list); |
dc434e05 | 1863 | unlock: |
cf392d10 | 1864 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1865 | return ret; |
1866 | } | |
1867 | ||
1868 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1869 | bool invoke) | |
1870 | { | |
1871 | int ret; | |
1872 | ||
1873 | cpus_read_lock(); | |
1874 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1875 | cpus_read_unlock(); |
cf392d10 TG |
1876 | return ret; |
1877 | } | |
1878 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1879 | ||
5b7aa87e | 1880 | /** |
71def423 | 1881 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1882 | * @state: The state to setup |
1883 | * @invoke: If true, the startup function is invoked for cpus where | |
1884 | * cpu state >= @state | |
1885 | * @startup: startup callback function | |
1886 | * @teardown: teardown callback function | |
1887 | * @multi_instance: State is set up for multiple instances which get | |
1888 | * added afterwards. | |
5b7aa87e | 1889 | * |
71def423 | 1890 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1891 | * Returns: |
1892 | * On success: | |
1893 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1894 | * 0 for all other states | |
1895 | * On failure: proper (negative) error code | |
5b7aa87e | 1896 | */ |
71def423 SAS |
1897 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1898 | const char *name, bool invoke, | |
1899 | int (*startup)(unsigned int cpu), | |
1900 | int (*teardown)(unsigned int cpu), | |
1901 | bool multi_instance) | |
5b7aa87e TG |
1902 | { |
1903 | int cpu, ret = 0; | |
b9d9d691 | 1904 | bool dynstate; |
5b7aa87e | 1905 | |
71def423 SAS |
1906 | lockdep_assert_cpus_held(); |
1907 | ||
5b7aa87e TG |
1908 | if (cpuhp_cb_check(state) || !name) |
1909 | return -EINVAL; | |
1910 | ||
dc434e05 | 1911 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1912 | |
dc280d93 TG |
1913 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1914 | multi_instance); | |
5b7aa87e | 1915 | |
b9d9d691 TG |
1916 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1917 | if (ret > 0 && dynstate) { | |
1918 | state = ret; | |
1919 | ret = 0; | |
1920 | } | |
1921 | ||
dc280d93 | 1922 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1923 | goto out; |
1924 | ||
1925 | /* | |
1926 | * Try to call the startup callback for each present cpu | |
1927 | * depending on the hotplug state of the cpu. | |
1928 | */ | |
1929 | for_each_present_cpu(cpu) { | |
1930 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1931 | int cpustate = st->state; | |
1932 | ||
1933 | if (cpustate < state) | |
1934 | continue; | |
1935 | ||
cf392d10 | 1936 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1937 | if (ret) { |
a724632c | 1938 | if (teardown) |
cf392d10 TG |
1939 | cpuhp_rollback_install(cpu, state, NULL); |
1940 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1941 | goto out; |
1942 | } | |
1943 | } | |
1944 | out: | |
dc434e05 | 1945 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1946 | /* |
1947 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1948 | * dynamically allocated state in case of success. | |
1949 | */ | |
b9d9d691 | 1950 | if (!ret && dynstate) |
5b7aa87e TG |
1951 | return state; |
1952 | return ret; | |
1953 | } | |
71def423 SAS |
1954 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1955 | ||
1956 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1957 | const char *name, bool invoke, | |
1958 | int (*startup)(unsigned int cpu), | |
1959 | int (*teardown)(unsigned int cpu), | |
1960 | bool multi_instance) | |
1961 | { | |
1962 | int ret; | |
1963 | ||
1964 | cpus_read_lock(); | |
1965 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1966 | teardown, multi_instance); | |
1967 | cpus_read_unlock(); | |
1968 | return ret; | |
1969 | } | |
5b7aa87e TG |
1970 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1971 | ||
cf392d10 TG |
1972 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1973 | struct hlist_node *node, bool invoke) | |
1974 | { | |
1975 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1976 | int cpu; | |
1977 | ||
1978 | BUG_ON(cpuhp_cb_check(state)); | |
1979 | ||
1980 | if (!sp->multi_instance) | |
1981 | return -EINVAL; | |
1982 | ||
8f553c49 | 1983 | cpus_read_lock(); |
dc434e05 SAS |
1984 | mutex_lock(&cpuhp_state_mutex); |
1985 | ||
cf392d10 TG |
1986 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1987 | goto remove; | |
1988 | /* | |
1989 | * Call the teardown callback for each present cpu depending | |
1990 | * on the hotplug state of the cpu. This function is not | |
1991 | * allowed to fail currently! | |
1992 | */ | |
1993 | for_each_present_cpu(cpu) { | |
1994 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1995 | int cpustate = st->state; | |
1996 | ||
1997 | if (cpustate >= state) | |
1998 | cpuhp_issue_call(cpu, state, false, node); | |
1999 | } | |
2000 | ||
2001 | remove: | |
cf392d10 TG |
2002 | hlist_del(node); |
2003 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 2004 | cpus_read_unlock(); |
cf392d10 TG |
2005 | |
2006 | return 0; | |
2007 | } | |
2008 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 2009 | |
5b7aa87e | 2010 | /** |
71def423 | 2011 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
2012 | * @state: The state to remove |
2013 | * @invoke: If true, the teardown function is invoked for cpus where | |
2014 | * cpu state >= @state | |
2015 | * | |
71def423 | 2016 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
2017 | * The teardown callback is currently not allowed to fail. Think |
2018 | * about module removal! | |
2019 | */ | |
71def423 | 2020 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 2021 | { |
cf392d10 | 2022 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
2023 | int cpu; |
2024 | ||
2025 | BUG_ON(cpuhp_cb_check(state)); | |
2026 | ||
71def423 | 2027 | lockdep_assert_cpus_held(); |
5b7aa87e | 2028 | |
dc434e05 | 2029 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
2030 | if (sp->multi_instance) { |
2031 | WARN(!hlist_empty(&sp->list), | |
2032 | "Error: Removing state %d which has instances left.\n", | |
2033 | state); | |
2034 | goto remove; | |
2035 | } | |
2036 | ||
a724632c | 2037 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
2038 | goto remove; |
2039 | ||
2040 | /* | |
2041 | * Call the teardown callback for each present cpu depending | |
2042 | * on the hotplug state of the cpu. This function is not | |
2043 | * allowed to fail currently! | |
2044 | */ | |
2045 | for_each_present_cpu(cpu) { | |
2046 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
2047 | int cpustate = st->state; | |
2048 | ||
2049 | if (cpustate >= state) | |
cf392d10 | 2050 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
2051 | } |
2052 | remove: | |
cf392d10 | 2053 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 2054 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
2055 | } |
2056 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
2057 | ||
2058 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
2059 | { | |
2060 | cpus_read_lock(); | |
2061 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 2062 | cpus_read_unlock(); |
5b7aa87e TG |
2063 | } |
2064 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
2065 | ||
dc8d37ed AB |
2066 | #ifdef CONFIG_HOTPLUG_SMT |
2067 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2068 | { | |
2069 | struct device *dev = get_cpu_device(cpu); | |
2070 | ||
2071 | dev->offline = true; | |
2072 | /* Tell user space about the state change */ | |
2073 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2074 | } | |
2075 | ||
2076 | static void cpuhp_online_cpu_device(unsigned int cpu) | |
2077 | { | |
2078 | struct device *dev = get_cpu_device(cpu); | |
2079 | ||
2080 | dev->offline = false; | |
2081 | /* Tell user space about the state change */ | |
2082 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2083 | } | |
2084 | ||
2085 | int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) | |
2086 | { | |
2087 | int cpu, ret = 0; | |
2088 | ||
2089 | cpu_maps_update_begin(); | |
2090 | for_each_online_cpu(cpu) { | |
2091 | if (topology_is_primary_thread(cpu)) | |
2092 | continue; | |
2093 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2094 | if (ret) | |
2095 | break; | |
2096 | /* | |
2097 | * As this needs to hold the cpu maps lock it's impossible | |
2098 | * to call device_offline() because that ends up calling | |
2099 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2100 | * needs to be held as this might race against in kernel | |
2101 | * abusers of the hotplug machinery (thermal management). | |
2102 | * | |
2103 | * So nothing would update device:offline state. That would | |
2104 | * leave the sysfs entry stale and prevent onlining after | |
2105 | * smt control has been changed to 'off' again. This is | |
2106 | * called under the sysfs hotplug lock, so it is properly | |
2107 | * serialized against the regular offline usage. | |
2108 | */ | |
2109 | cpuhp_offline_cpu_device(cpu); | |
2110 | } | |
2111 | if (!ret) | |
2112 | cpu_smt_control = ctrlval; | |
2113 | cpu_maps_update_done(); | |
2114 | return ret; | |
2115 | } | |
2116 | ||
2117 | int cpuhp_smt_enable(void) | |
2118 | { | |
2119 | int cpu, ret = 0; | |
2120 | ||
2121 | cpu_maps_update_begin(); | |
2122 | cpu_smt_control = CPU_SMT_ENABLED; | |
2123 | for_each_present_cpu(cpu) { | |
2124 | /* Skip online CPUs and CPUs on offline nodes */ | |
2125 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2126 | continue; | |
2127 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2128 | if (ret) | |
2129 | break; | |
2130 | /* See comment in cpuhp_smt_disable() */ | |
2131 | cpuhp_online_cpu_device(cpu); | |
2132 | } | |
2133 | cpu_maps_update_done(); | |
2134 | return ret; | |
2135 | } | |
2136 | #endif | |
2137 | ||
98f8cdce TG |
2138 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
2139 | static ssize_t show_cpuhp_state(struct device *dev, | |
2140 | struct device_attribute *attr, char *buf) | |
2141 | { | |
2142 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2143 | ||
2144 | return sprintf(buf, "%d\n", st->state); | |
2145 | } | |
2146 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
2147 | ||
757c989b TG |
2148 | static ssize_t write_cpuhp_target(struct device *dev, |
2149 | struct device_attribute *attr, | |
2150 | const char *buf, size_t count) | |
2151 | { | |
2152 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2153 | struct cpuhp_step *sp; | |
2154 | int target, ret; | |
2155 | ||
2156 | ret = kstrtoint(buf, 10, &target); | |
2157 | if (ret) | |
2158 | return ret; | |
2159 | ||
2160 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
2161 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
2162 | return -EINVAL; | |
2163 | #else | |
2164 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
2165 | return -EINVAL; | |
2166 | #endif | |
2167 | ||
2168 | ret = lock_device_hotplug_sysfs(); | |
2169 | if (ret) | |
2170 | return ret; | |
2171 | ||
2172 | mutex_lock(&cpuhp_state_mutex); | |
2173 | sp = cpuhp_get_step(target); | |
2174 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
2175 | mutex_unlock(&cpuhp_state_mutex); | |
2176 | if (ret) | |
40da1b11 | 2177 | goto out; |
757c989b TG |
2178 | |
2179 | if (st->state < target) | |
33c3736e | 2180 | ret = cpu_up(dev->id, target); |
757c989b | 2181 | else |
33c3736e | 2182 | ret = cpu_down(dev->id, target); |
40da1b11 | 2183 | out: |
757c989b TG |
2184 | unlock_device_hotplug(); |
2185 | return ret ? ret : count; | |
2186 | } | |
2187 | ||
98f8cdce TG |
2188 | static ssize_t show_cpuhp_target(struct device *dev, |
2189 | struct device_attribute *attr, char *buf) | |
2190 | { | |
2191 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2192 | ||
2193 | return sprintf(buf, "%d\n", st->target); | |
2194 | } | |
757c989b | 2195 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 2196 | |
1db49484 PZ |
2197 | |
2198 | static ssize_t write_cpuhp_fail(struct device *dev, | |
2199 | struct device_attribute *attr, | |
2200 | const char *buf, size_t count) | |
2201 | { | |
2202 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2203 | struct cpuhp_step *sp; | |
2204 | int fail, ret; | |
2205 | ||
2206 | ret = kstrtoint(buf, 10, &fail); | |
2207 | if (ret) | |
2208 | return ret; | |
2209 | ||
33d4a5a7 ET |
2210 | if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
2211 | return -EINVAL; | |
2212 | ||
1db49484 PZ |
2213 | /* |
2214 | * Cannot fail STARTING/DYING callbacks. | |
2215 | */ | |
2216 | if (cpuhp_is_atomic_state(fail)) | |
2217 | return -EINVAL; | |
2218 | ||
2219 | /* | |
2220 | * Cannot fail anything that doesn't have callbacks. | |
2221 | */ | |
2222 | mutex_lock(&cpuhp_state_mutex); | |
2223 | sp = cpuhp_get_step(fail); | |
2224 | if (!sp->startup.single && !sp->teardown.single) | |
2225 | ret = -EINVAL; | |
2226 | mutex_unlock(&cpuhp_state_mutex); | |
2227 | if (ret) | |
2228 | return ret; | |
2229 | ||
2230 | st->fail = fail; | |
2231 | ||
2232 | return count; | |
2233 | } | |
2234 | ||
2235 | static ssize_t show_cpuhp_fail(struct device *dev, | |
2236 | struct device_attribute *attr, char *buf) | |
2237 | { | |
2238 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
2239 | ||
2240 | return sprintf(buf, "%d\n", st->fail); | |
2241 | } | |
2242 | ||
2243 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
2244 | ||
98f8cdce TG |
2245 | static struct attribute *cpuhp_cpu_attrs[] = { |
2246 | &dev_attr_state.attr, | |
2247 | &dev_attr_target.attr, | |
1db49484 | 2248 | &dev_attr_fail.attr, |
98f8cdce TG |
2249 | NULL |
2250 | }; | |
2251 | ||
993647a2 | 2252 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
2253 | .attrs = cpuhp_cpu_attrs, |
2254 | .name = "hotplug", | |
2255 | NULL | |
2256 | }; | |
2257 | ||
2258 | static ssize_t show_cpuhp_states(struct device *dev, | |
2259 | struct device_attribute *attr, char *buf) | |
2260 | { | |
2261 | ssize_t cur, res = 0; | |
2262 | int i; | |
2263 | ||
2264 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 2265 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
2266 | struct cpuhp_step *sp = cpuhp_get_step(i); |
2267 | ||
2268 | if (sp->name) { | |
2269 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
2270 | buf += cur; | |
2271 | res += cur; | |
2272 | } | |
2273 | } | |
2274 | mutex_unlock(&cpuhp_state_mutex); | |
2275 | return res; | |
2276 | } | |
2277 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2278 | ||
2279 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2280 | &dev_attr_states.attr, | |
2281 | NULL | |
2282 | }; | |
2283 | ||
993647a2 | 2284 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2285 | .attrs = cpuhp_cpu_root_attrs, |
2286 | .name = "hotplug", | |
2287 | NULL | |
2288 | }; | |
2289 | ||
05736e4a TG |
2290 | #ifdef CONFIG_HOTPLUG_SMT |
2291 | ||
05736e4a | 2292 | static ssize_t |
de7b77e5 JP |
2293 | __store_smt_control(struct device *dev, struct device_attribute *attr, |
2294 | const char *buf, size_t count) | |
05736e4a TG |
2295 | { |
2296 | int ctrlval, ret; | |
2297 | ||
2298 | if (sysfs_streq(buf, "on")) | |
2299 | ctrlval = CPU_SMT_ENABLED; | |
2300 | else if (sysfs_streq(buf, "off")) | |
2301 | ctrlval = CPU_SMT_DISABLED; | |
2302 | else if (sysfs_streq(buf, "forceoff")) | |
2303 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2304 | else | |
2305 | return -EINVAL; | |
2306 | ||
2307 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2308 | return -EPERM; | |
2309 | ||
2310 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2311 | return -ENODEV; | |
2312 | ||
2313 | ret = lock_device_hotplug_sysfs(); | |
2314 | if (ret) | |
2315 | return ret; | |
2316 | ||
2317 | if (ctrlval != cpu_smt_control) { | |
2318 | switch (ctrlval) { | |
2319 | case CPU_SMT_ENABLED: | |
215af549 | 2320 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2321 | break; |
2322 | case CPU_SMT_DISABLED: | |
2323 | case CPU_SMT_FORCE_DISABLED: | |
2324 | ret = cpuhp_smt_disable(ctrlval); | |
2325 | break; | |
2326 | } | |
2327 | } | |
2328 | ||
2329 | unlock_device_hotplug(); | |
2330 | return ret ? ret : count; | |
2331 | } | |
de7b77e5 JP |
2332 | |
2333 | #else /* !CONFIG_HOTPLUG_SMT */ | |
2334 | static ssize_t | |
2335 | __store_smt_control(struct device *dev, struct device_attribute *attr, | |
2336 | const char *buf, size_t count) | |
2337 | { | |
2338 | return -ENODEV; | |
2339 | } | |
2340 | #endif /* CONFIG_HOTPLUG_SMT */ | |
2341 | ||
2342 | static const char *smt_states[] = { | |
2343 | [CPU_SMT_ENABLED] = "on", | |
2344 | [CPU_SMT_DISABLED] = "off", | |
2345 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2346 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2347 | [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented", | |
2348 | }; | |
2349 | ||
2350 | static ssize_t | |
2351 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2352 | { | |
2353 | const char *state = smt_states[cpu_smt_control]; | |
2354 | ||
2355 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", state); | |
2356 | } | |
2357 | ||
2358 | static ssize_t | |
2359 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2360 | const char *buf, size_t count) | |
2361 | { | |
2362 | return __store_smt_control(dev, attr, buf, count); | |
2363 | } | |
05736e4a TG |
2364 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
2365 | ||
2366 | static ssize_t | |
2367 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2368 | { | |
de7b77e5 | 2369 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", sched_smt_active()); |
05736e4a TG |
2370 | } |
2371 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2372 | ||
2373 | static struct attribute *cpuhp_smt_attrs[] = { | |
2374 | &dev_attr_control.attr, | |
2375 | &dev_attr_active.attr, | |
2376 | NULL | |
2377 | }; | |
2378 | ||
2379 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2380 | .attrs = cpuhp_smt_attrs, | |
2381 | .name = "smt", | |
2382 | NULL | |
2383 | }; | |
2384 | ||
de7b77e5 | 2385 | static int __init cpu_smt_sysfs_init(void) |
05736e4a | 2386 | { |
05736e4a TG |
2387 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2388 | &cpuhp_smt_attr_group); | |
2389 | } | |
2390 | ||
98f8cdce TG |
2391 | static int __init cpuhp_sysfs_init(void) |
2392 | { | |
2393 | int cpu, ret; | |
2394 | ||
de7b77e5 | 2395 | ret = cpu_smt_sysfs_init(); |
05736e4a TG |
2396 | if (ret) |
2397 | return ret; | |
2398 | ||
98f8cdce TG |
2399 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2400 | &cpuhp_cpu_root_attr_group); | |
2401 | if (ret) | |
2402 | return ret; | |
2403 | ||
2404 | for_each_possible_cpu(cpu) { | |
2405 | struct device *dev = get_cpu_device(cpu); | |
2406 | ||
2407 | if (!dev) | |
2408 | continue; | |
2409 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2410 | if (ret) | |
2411 | return ret; | |
2412 | } | |
2413 | return 0; | |
2414 | } | |
2415 | device_initcall(cpuhp_sysfs_init); | |
de7b77e5 | 2416 | #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */ |
98f8cdce | 2417 | |
e56b3bc7 LT |
2418 | /* |
2419 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2420 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2421 | * | |
e0b582ec | 2422 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2423 | * mask value that has a single bit set only. |
2424 | */ | |
b8d317d1 | 2425 | |
e56b3bc7 | 2426 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2427 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2428 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2429 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2430 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2431 | |
e56b3bc7 LT |
2432 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2433 | ||
2434 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2435 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2436 | #if BITS_PER_LONG > 32 | |
2437 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2438 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2439 | #endif |
2440 | }; | |
e56b3bc7 | 2441 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2442 | |
2443 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2444 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2445 | |
2446 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2447 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2448 | = {CPU_BITS_ALL}; |
b3199c02 | 2449 | #else |
4b804c85 | 2450 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2451 | #endif |
4b804c85 | 2452 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2453 | |
4b804c85 RV |
2454 | struct cpumask __cpu_online_mask __read_mostly; |
2455 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2456 | |
4b804c85 RV |
2457 | struct cpumask __cpu_present_mask __read_mostly; |
2458 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2459 | |
4b804c85 RV |
2460 | struct cpumask __cpu_active_mask __read_mostly; |
2461 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2462 | |
0c09ab96 TG |
2463 | atomic_t __num_online_cpus __read_mostly; |
2464 | EXPORT_SYMBOL(__num_online_cpus); | |
2465 | ||
3fa41520 RR |
2466 | void init_cpu_present(const struct cpumask *src) |
2467 | { | |
c4c54dd1 | 2468 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2469 | } |
2470 | ||
2471 | void init_cpu_possible(const struct cpumask *src) | |
2472 | { | |
c4c54dd1 | 2473 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2474 | } |
2475 | ||
2476 | void init_cpu_online(const struct cpumask *src) | |
2477 | { | |
c4c54dd1 | 2478 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2479 | } |
cff7d378 | 2480 | |
0c09ab96 TG |
2481 | void set_cpu_online(unsigned int cpu, bool online) |
2482 | { | |
2483 | /* | |
2484 | * atomic_inc/dec() is required to handle the horrid abuse of this | |
2485 | * function by the reboot and kexec code which invoke it from | |
2486 | * IPI/NMI broadcasts when shutting down CPUs. Invocation from | |
2487 | * regular CPU hotplug is properly serialized. | |
2488 | * | |
2489 | * Note, that the fact that __num_online_cpus is of type atomic_t | |
2490 | * does not protect readers which are not serialized against | |
2491 | * concurrent hotplug operations. | |
2492 | */ | |
2493 | if (online) { | |
2494 | if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask)) | |
2495 | atomic_inc(&__num_online_cpus); | |
2496 | } else { | |
2497 | if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask)) | |
2498 | atomic_dec(&__num_online_cpus); | |
2499 | } | |
2500 | } | |
2501 | ||
cff7d378 TG |
2502 | /* |
2503 | * Activate the first processor. | |
2504 | */ | |
2505 | void __init boot_cpu_init(void) | |
2506 | { | |
2507 | int cpu = smp_processor_id(); | |
2508 | ||
2509 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2510 | set_cpu_online(cpu, true); | |
2511 | set_cpu_active(cpu, true); | |
2512 | set_cpu_present(cpu, true); | |
2513 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2514 | |
2515 | #ifdef CONFIG_SMP | |
2516 | __boot_cpu_id = cpu; | |
2517 | #endif | |
cff7d378 TG |
2518 | } |
2519 | ||
2520 | /* | |
2521 | * Must be called _AFTER_ setting up the per_cpu areas | |
2522 | */ | |
b5b1404d | 2523 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2524 | { |
269777aa | 2525 | #ifdef CONFIG_SMP |
e797bda3 | 2526 | cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask); |
269777aa | 2527 | #endif |
0cc3cd21 | 2528 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2529 | } |
98af8452 | 2530 | |
731dc9df TH |
2531 | /* |
2532 | * These are used for a global "mitigations=" cmdline option for toggling | |
2533 | * optional CPU mitigations. | |
2534 | */ | |
2535 | enum cpu_mitigations { | |
2536 | CPU_MITIGATIONS_OFF, | |
2537 | CPU_MITIGATIONS_AUTO, | |
2538 | CPU_MITIGATIONS_AUTO_NOSMT, | |
2539 | }; | |
2540 | ||
2541 | static enum cpu_mitigations cpu_mitigations __ro_after_init = | |
2542 | CPU_MITIGATIONS_AUTO; | |
98af8452 JP |
2543 | |
2544 | static int __init mitigations_parse_cmdline(char *arg) | |
2545 | { | |
2546 | if (!strcmp(arg, "off")) | |
2547 | cpu_mitigations = CPU_MITIGATIONS_OFF; | |
2548 | else if (!strcmp(arg, "auto")) | |
2549 | cpu_mitigations = CPU_MITIGATIONS_AUTO; | |
2550 | else if (!strcmp(arg, "auto,nosmt")) | |
2551 | cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; | |
1bf72720 GU |
2552 | else |
2553 | pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", | |
2554 | arg); | |
98af8452 JP |
2555 | |
2556 | return 0; | |
2557 | } | |
2558 | early_param("mitigations", mitigations_parse_cmdline); | |
731dc9df TH |
2559 | |
2560 | /* mitigations=off */ | |
2561 | bool cpu_mitigations_off(void) | |
2562 | { | |
2563 | return cpu_mitigations == CPU_MITIGATIONS_OFF; | |
2564 | } | |
2565 | EXPORT_SYMBOL_GPL(cpu_mitigations_off); | |
2566 | ||
2567 | /* mitigations=auto,nosmt */ | |
2568 | bool cpu_mitigations_auto_nosmt(void) | |
2569 | { | |
2570 | return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; | |
2571 | } | |
2572 | EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |