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Commit | Line | Data |
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1da177e4 LT |
1 | /* CPU control. |
2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell | |
3 | * | |
4 | * This code is licenced under the GPL. | |
5 | */ | |
6 | #include <linux/proc_fs.h> | |
7 | #include <linux/smp.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/notifier.h> | |
3f07c014 | 10 | #include <linux/sched/signal.h> |
ef8bd77f | 11 | #include <linux/sched/hotplug.h> |
29930025 | 12 | #include <linux/sched/task.h> |
1da177e4 LT |
13 | #include <linux/unistd.h> |
14 | #include <linux/cpu.h> | |
cb79295e AV |
15 | #include <linux/oom.h> |
16 | #include <linux/rcupdate.h> | |
9984de1a | 17 | #include <linux/export.h> |
e4cc2f87 | 18 | #include <linux/bug.h> |
1da177e4 LT |
19 | #include <linux/kthread.h> |
20 | #include <linux/stop_machine.h> | |
81615b62 | 21 | #include <linux/mutex.h> |
5a0e3ad6 | 22 | #include <linux/gfp.h> |
79cfbdfa | 23 | #include <linux/suspend.h> |
a19423b9 | 24 | #include <linux/lockdep.h> |
345527b1 | 25 | #include <linux/tick.h> |
a8994181 | 26 | #include <linux/irq.h> |
941154bd | 27 | #include <linux/nmi.h> |
4cb28ced | 28 | #include <linux/smpboot.h> |
e6d4989a | 29 | #include <linux/relay.h> |
6731d4f1 | 30 | #include <linux/slab.h> |
fc8dffd3 | 31 | #include <linux/percpu-rwsem.h> |
cff7d378 | 32 | |
bb3632c6 | 33 | #include <trace/events/power.h> |
cff7d378 TG |
34 | #define CREATE_TRACE_POINTS |
35 | #include <trace/events/cpuhp.h> | |
1da177e4 | 36 | |
38498a67 TG |
37 | #include "smpboot.h" |
38 | ||
cff7d378 TG |
39 | /** |
40 | * cpuhp_cpu_state - Per cpu hotplug state storage | |
41 | * @state: The current cpu state | |
42 | * @target: The target state | |
4cb28ced TG |
43 | * @thread: Pointer to the hotplug thread |
44 | * @should_run: Thread should execute | |
3b9d6da6 | 45 | * @rollback: Perform a rollback |
a724632c TG |
46 | * @single: Single callback invocation |
47 | * @bringup: Single callback bringup or teardown selector | |
48 | * @cb_state: The state for a single callback (install/uninstall) | |
4cb28ced | 49 | * @result: Result of the operation |
5ebe7742 PZ |
50 | * @done_up: Signal completion to the issuer of the task for cpu-up |
51 | * @done_down: Signal completion to the issuer of the task for cpu-down | |
cff7d378 TG |
52 | */ |
53 | struct cpuhp_cpu_state { | |
54 | enum cpuhp_state state; | |
55 | enum cpuhp_state target; | |
1db49484 | 56 | enum cpuhp_state fail; |
4cb28ced TG |
57 | #ifdef CONFIG_SMP |
58 | struct task_struct *thread; | |
59 | bool should_run; | |
3b9d6da6 | 60 | bool rollback; |
a724632c TG |
61 | bool single; |
62 | bool bringup; | |
3762ba90 | 63 | bool booted_once; |
cf392d10 | 64 | struct hlist_node *node; |
4dddfb5f | 65 | struct hlist_node *last; |
4cb28ced | 66 | enum cpuhp_state cb_state; |
4cb28ced | 67 | int result; |
5ebe7742 PZ |
68 | struct completion done_up; |
69 | struct completion done_down; | |
4cb28ced | 70 | #endif |
cff7d378 TG |
71 | }; |
72 | ||
1db49484 PZ |
73 | static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
74 | .fail = CPUHP_INVALID, | |
75 | }; | |
cff7d378 | 76 | |
49dfe2a6 | 77 | #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
5f4b55e1 PZ |
78 | static struct lockdep_map cpuhp_state_up_map = |
79 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); | |
80 | static struct lockdep_map cpuhp_state_down_map = | |
81 | STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); | |
82 | ||
83 | ||
76dc6c09 | 84 | static inline void cpuhp_lock_acquire(bool bringup) |
5f4b55e1 PZ |
85 | { |
86 | lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
87 | } | |
88 | ||
76dc6c09 | 89 | static inline void cpuhp_lock_release(bool bringup) |
5f4b55e1 PZ |
90 | { |
91 | lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); | |
92 | } | |
93 | #else | |
94 | ||
76dc6c09 MM |
95 | static inline void cpuhp_lock_acquire(bool bringup) { } |
96 | static inline void cpuhp_lock_release(bool bringup) { } | |
5f4b55e1 | 97 | |
49dfe2a6 TG |
98 | #endif |
99 | ||
cff7d378 TG |
100 | /** |
101 | * cpuhp_step - Hotplug state machine step | |
102 | * @name: Name of the step | |
103 | * @startup: Startup function of the step | |
104 | * @teardown: Teardown function of the step | |
105 | * @skip_onerr: Do not invoke the functions on error rollback | |
106 | * Will go away once the notifiers are gone | |
757c989b | 107 | * @cant_stop: Bringup/teardown can't be stopped at this step |
cff7d378 TG |
108 | */ |
109 | struct cpuhp_step { | |
cf392d10 TG |
110 | const char *name; |
111 | union { | |
3c1627e9 TG |
112 | int (*single)(unsigned int cpu); |
113 | int (*multi)(unsigned int cpu, | |
114 | struct hlist_node *node); | |
115 | } startup; | |
cf392d10 | 116 | union { |
3c1627e9 TG |
117 | int (*single)(unsigned int cpu); |
118 | int (*multi)(unsigned int cpu, | |
119 | struct hlist_node *node); | |
120 | } teardown; | |
cf392d10 TG |
121 | struct hlist_head list; |
122 | bool skip_onerr; | |
123 | bool cant_stop; | |
124 | bool multi_instance; | |
cff7d378 TG |
125 | }; |
126 | ||
98f8cdce | 127 | static DEFINE_MUTEX(cpuhp_state_mutex); |
cff7d378 | 128 | static struct cpuhp_step cpuhp_bp_states[]; |
4baa0afc | 129 | static struct cpuhp_step cpuhp_ap_states[]; |
cff7d378 | 130 | |
a724632c TG |
131 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
132 | { | |
133 | /* | |
134 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
135 | * purposes as that state is handled explicitly in cpu_down. | |
136 | */ | |
137 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
138 | } | |
139 | ||
140 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) | |
141 | { | |
142 | struct cpuhp_step *sp; | |
143 | ||
144 | sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; | |
145 | return sp + state; | |
146 | } | |
147 | ||
cff7d378 TG |
148 | /** |
149 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
150 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 151 | * @state: The state to do callbacks for |
a724632c | 152 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
153 | * @node: For multi-instance, do a single entry callback for install/remove |
154 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 155 | * |
cf392d10 | 156 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 157 | */ |
a724632c | 158 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
159 | bool bringup, struct hlist_node *node, |
160 | struct hlist_node **lastp) | |
cff7d378 TG |
161 | { |
162 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 163 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
164 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
165 | int (*cb)(unsigned int cpu); | |
166 | int ret, cnt; | |
167 | ||
1db49484 PZ |
168 | if (st->fail == state) { |
169 | st->fail = CPUHP_INVALID; | |
170 | ||
171 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
172 | return 0; | |
173 | ||
174 | return -EAGAIN; | |
175 | } | |
176 | ||
cf392d10 | 177 | if (!step->multi_instance) { |
96abb968 | 178 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 179 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
180 | if (!cb) |
181 | return 0; | |
a724632c | 182 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 183 | ret = cb(cpu); |
a724632c | 184 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
185 | return ret; |
186 | } | |
3c1627e9 | 187 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
188 | if (!cbm) |
189 | return 0; | |
190 | ||
191 | /* Single invocation for instance add/remove */ | |
192 | if (node) { | |
96abb968 | 193 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
194 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
195 | ret = cbm(cpu, node); | |
196 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
197 | return ret; | |
198 | } | |
199 | ||
200 | /* State transition. Invoke on all instances */ | |
201 | cnt = 0; | |
202 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
203 | if (lastp && node == *lastp) |
204 | break; | |
205 | ||
cf392d10 TG |
206 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
207 | ret = cbm(cpu, node); | |
208 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
209 | if (ret) { |
210 | if (!lastp) | |
211 | goto err; | |
212 | ||
213 | *lastp = node; | |
214 | return ret; | |
215 | } | |
cf392d10 TG |
216 | cnt++; |
217 | } | |
96abb968 PZ |
218 | if (lastp) |
219 | *lastp = NULL; | |
cf392d10 TG |
220 | return 0; |
221 | err: | |
222 | /* Rollback the instances if one failed */ | |
3c1627e9 | 223 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
224 | if (!cbm) |
225 | return ret; | |
226 | ||
227 | hlist_for_each(node, &step->list) { | |
228 | if (!cnt--) | |
229 | break; | |
724a8688 PZ |
230 | |
231 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
232 | ret = cbm(cpu, node); | |
233 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
234 | /* | |
235 | * Rollback must not fail, | |
236 | */ | |
237 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
238 | } |
239 | return ret; | |
240 | } | |
241 | ||
98a79d6a | 242 | #ifdef CONFIG_SMP |
5ebe7742 PZ |
243 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
244 | { | |
245 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
246 | wait_for_completion(done); | |
247 | } | |
248 | ||
249 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
250 | { | |
251 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
252 | complete(done); | |
253 | } | |
254 | ||
255 | /* | |
256 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
257 | */ | |
258 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
259 | { | |
260 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
261 | } | |
262 | ||
b3199c02 | 263 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 264 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
265 | bool cpuhp_tasks_frozen; |
266 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 267 | |
79a6cdeb | 268 | /* |
93ae4f97 SB |
269 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
270 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
271 | */ |
272 | void cpu_maps_update_begin(void) | |
273 | { | |
274 | mutex_lock(&cpu_add_remove_lock); | |
275 | } | |
276 | ||
277 | void cpu_maps_update_done(void) | |
278 | { | |
279 | mutex_unlock(&cpu_add_remove_lock); | |
280 | } | |
1da177e4 | 281 | |
fc8dffd3 TG |
282 | /* |
283 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
284 | * Should always be manipulated under cpu_add_remove_lock |
285 | */ | |
286 | static int cpu_hotplug_disabled; | |
287 | ||
79a6cdeb LJ |
288 | #ifdef CONFIG_HOTPLUG_CPU |
289 | ||
fc8dffd3 | 290 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 291 | |
8f553c49 | 292 | void cpus_read_lock(void) |
a9d9baa1 | 293 | { |
fc8dffd3 | 294 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 295 | } |
8f553c49 | 296 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 297 | |
8f553c49 | 298 | void cpus_read_unlock(void) |
a9d9baa1 | 299 | { |
fc8dffd3 | 300 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 301 | } |
8f553c49 | 302 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 303 | |
8f553c49 | 304 | void cpus_write_lock(void) |
d221938c | 305 | { |
fc8dffd3 | 306 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 307 | } |
87af9e7f | 308 | |
8f553c49 | 309 | void cpus_write_unlock(void) |
d221938c | 310 | { |
fc8dffd3 | 311 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
312 | } |
313 | ||
fc8dffd3 | 314 | void lockdep_assert_cpus_held(void) |
d221938c | 315 | { |
fc8dffd3 | 316 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 317 | } |
79a6cdeb | 318 | |
16e53dbf SB |
319 | /* |
320 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
321 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
322 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
323 | * hotplug path before performing hotplug operations. So acquiring that lock | |
324 | * guarantees mutual exclusion from any currently running hotplug operations. | |
325 | */ | |
326 | void cpu_hotplug_disable(void) | |
327 | { | |
328 | cpu_maps_update_begin(); | |
89af7ba5 | 329 | cpu_hotplug_disabled++; |
16e53dbf SB |
330 | cpu_maps_update_done(); |
331 | } | |
32145c46 | 332 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 333 | |
01b41159 LW |
334 | static void __cpu_hotplug_enable(void) |
335 | { | |
336 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
337 | return; | |
338 | cpu_hotplug_disabled--; | |
339 | } | |
340 | ||
16e53dbf SB |
341 | void cpu_hotplug_enable(void) |
342 | { | |
343 | cpu_maps_update_begin(); | |
01b41159 | 344 | __cpu_hotplug_enable(); |
16e53dbf SB |
345 | cpu_maps_update_done(); |
346 | } | |
32145c46 | 347 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
b9d10be7 | 348 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 349 | |
3762ba90 TG |
350 | #ifdef CONFIG_HOTPLUG_SMT |
351 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
275b72a9 | 352 | EXPORT_SYMBOL_GPL(cpu_smt_control); |
3762ba90 | 353 | |
ade31b9e TG |
354 | static bool cpu_smt_available __read_mostly; |
355 | ||
44219799 | 356 | void __init cpu_smt_disable(bool force) |
3762ba90 | 357 | { |
44219799 JK |
358 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || |
359 | cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
360 | return; | |
361 | ||
362 | if (force) { | |
3762ba90 TG |
363 | pr_info("SMT: Force disabled\n"); |
364 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
44219799 JK |
365 | } else { |
366 | cpu_smt_control = CPU_SMT_DISABLED; | |
3762ba90 | 367 | } |
44219799 JK |
368 | } |
369 | ||
483ec3c6 TG |
370 | /* |
371 | * The decision whether SMT is supported can only be done after the full | |
ade31b9e TG |
372 | * CPU identification. Called from architecture code before non boot CPUs |
373 | * are brought up. | |
483ec3c6 | 374 | */ |
ade31b9e | 375 | void __init cpu_smt_check_topology_early(void) |
483ec3c6 TG |
376 | { |
377 | if (!topology_smt_supported()) | |
378 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; | |
379 | } | |
380 | ||
ade31b9e TG |
381 | /* |
382 | * If SMT was disabled by BIOS, detect it here, after the CPUs have been | |
383 | * brought online. This ensures the smt/l1tf sysfs entries are consistent | |
384 | * with reality. cpu_smt_available is set to true during the bringup of non | |
385 | * boot CPUs when a SMT sibling is detected. Note, this may overwrite | |
386 | * cpu_smt_control's previous setting. | |
387 | */ | |
388 | void __init cpu_smt_check_topology(void) | |
389 | { | |
390 | if (!cpu_smt_available) | |
391 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; | |
392 | } | |
393 | ||
44219799 JK |
394 | static int __init smt_cmdline_disable(char *str) |
395 | { | |
396 | cpu_smt_disable(str && !strcmp(str, "force")); | |
3762ba90 TG |
397 | return 0; |
398 | } | |
399 | early_param("nosmt", smt_cmdline_disable); | |
400 | ||
401 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
402 | { | |
ade31b9e | 403 | if (topology_is_primary_thread(cpu)) |
3762ba90 TG |
404 | return true; |
405 | ||
ade31b9e TG |
406 | /* |
407 | * If the CPU is not a 'primary' thread and the booted_once bit is | |
408 | * set then the processor has SMT support. Store this information | |
409 | * for the late check of SMT support in cpu_smt_check_topology(). | |
410 | */ | |
411 | if (per_cpu(cpuhp_state, cpu).booted_once) | |
412 | cpu_smt_available = true; | |
413 | ||
414 | if (cpu_smt_control == CPU_SMT_ENABLED) | |
3762ba90 TG |
415 | return true; |
416 | ||
417 | /* | |
418 | * On x86 it's required to boot all logical CPUs at least once so | |
419 | * that the init code can get a chance to set CR4.MCE on each | |
420 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any | |
421 | * core will shutdown the machine. | |
422 | */ | |
423 | return !per_cpu(cpuhp_state, cpu).booted_once; | |
424 | } | |
425 | #else | |
426 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
427 | #endif | |
428 | ||
4dddfb5f PZ |
429 | static inline enum cpuhp_state |
430 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
431 | { | |
432 | enum cpuhp_state prev_state = st->state; | |
433 | ||
434 | st->rollback = false; | |
435 | st->last = NULL; | |
436 | ||
437 | st->target = target; | |
438 | st->single = false; | |
439 | st->bringup = st->state < target; | |
440 | ||
441 | return prev_state; | |
442 | } | |
443 | ||
444 | static inline void | |
445 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
446 | { | |
447 | st->rollback = true; | |
448 | ||
449 | /* | |
450 | * If we have st->last we need to undo partial multi_instance of this | |
451 | * state first. Otherwise start undo at the previous state. | |
452 | */ | |
453 | if (!st->last) { | |
454 | if (st->bringup) | |
455 | st->state--; | |
456 | else | |
457 | st->state++; | |
458 | } | |
459 | ||
460 | st->target = prev_state; | |
461 | st->bringup = !st->bringup; | |
462 | } | |
463 | ||
464 | /* Regular hotplug invocation of the AP hotplug thread */ | |
465 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
466 | { | |
467 | if (!st->single && st->state == st->target) | |
468 | return; | |
469 | ||
470 | st->result = 0; | |
471 | /* | |
472 | * Make sure the above stores are visible before should_run becomes | |
473 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
474 | */ | |
475 | smp_mb(); | |
476 | st->should_run = true; | |
477 | wake_up_process(st->thread); | |
5ebe7742 | 478 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
479 | } |
480 | ||
481 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
482 | { | |
483 | enum cpuhp_state prev_state; | |
484 | int ret; | |
485 | ||
486 | prev_state = cpuhp_set_state(st, target); | |
487 | __cpuhp_kick_ap(st); | |
488 | if ((ret = st->result)) { | |
489 | cpuhp_reset_state(st, prev_state); | |
490 | __cpuhp_kick_ap(st); | |
491 | } | |
492 | ||
493 | return ret; | |
494 | } | |
9cd4f1a4 | 495 | |
8df3e07e TG |
496 | static int bringup_wait_for_ap(unsigned int cpu) |
497 | { | |
498 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
499 | ||
9cd4f1a4 | 500 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 501 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
502 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
503 | return -ECANCELED; | |
9cd4f1a4 TG |
504 | |
505 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ | |
506 | stop_machine_unpark(cpu); | |
507 | kthread_unpark(st->thread); | |
508 | ||
3762ba90 TG |
509 | /* |
510 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
511 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
512 | * CPU marked itself as booted_once in cpu_notify_starting() so the | |
513 | * cpu_smt_allowed() check will now return false if this is not the | |
514 | * primary sibling. | |
515 | */ | |
516 | if (!cpu_smt_allowed(cpu)) | |
517 | return -ECANCELED; | |
518 | ||
4dddfb5f PZ |
519 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
520 | return 0; | |
521 | ||
522 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
523 | } |
524 | ||
ba997462 TG |
525 | static int bringup_cpu(unsigned int cpu) |
526 | { | |
527 | struct task_struct *idle = idle_thread_get(cpu); | |
528 | int ret; | |
529 | ||
aa877175 BO |
530 | /* |
531 | * Some architectures have to walk the irq descriptors to | |
532 | * setup the vector space for the cpu which comes online. | |
533 | * Prevent irq alloc/free across the bringup. | |
534 | */ | |
535 | irq_lock_sparse(); | |
536 | ||
ba997462 TG |
537 | /* Arch-specific enabling code. */ |
538 | ret = __cpu_up(cpu, idle); | |
aa877175 | 539 | irq_unlock_sparse(); |
530e9b76 | 540 | if (ret) |
ba997462 | 541 | return ret; |
9cd4f1a4 | 542 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
543 | } |
544 | ||
2e1a3483 TG |
545 | /* |
546 | * Hotplug state machine related functions | |
547 | */ | |
2e1a3483 | 548 | |
a724632c | 549 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 TG |
550 | { |
551 | for (st->state--; st->state > st->target; st->state--) { | |
a724632c | 552 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
2e1a3483 TG |
553 | |
554 | if (!step->skip_onerr) | |
96abb968 | 555 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); |
2e1a3483 TG |
556 | } |
557 | } | |
558 | ||
559 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
a724632c | 560 | enum cpuhp_state target) |
2e1a3483 TG |
561 | { |
562 | enum cpuhp_state prev_state = st->state; | |
563 | int ret = 0; | |
564 | ||
565 | while (st->state < target) { | |
2e1a3483 | 566 | st->state++; |
96abb968 | 567 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 TG |
568 | if (ret) { |
569 | st->target = prev_state; | |
a724632c | 570 | undo_cpu_up(cpu, st); |
2e1a3483 TG |
571 | break; |
572 | } | |
573 | } | |
574 | return ret; | |
575 | } | |
576 | ||
4cb28ced TG |
577 | /* |
578 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
579 | */ | |
580 | static void cpuhp_create(unsigned int cpu) | |
581 | { | |
582 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
583 | ||
5ebe7742 PZ |
584 | init_completion(&st->done_up); |
585 | init_completion(&st->done_down); | |
4cb28ced TG |
586 | } |
587 | ||
588 | static int cpuhp_should_run(unsigned int cpu) | |
589 | { | |
590 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
591 | ||
592 | return st->should_run; | |
593 | } | |
594 | ||
4cb28ced TG |
595 | /* |
596 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
597 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
598 | * |
599 | * Each invocation of this function by the smpboot thread does a single AP | |
600 | * state callback. | |
601 | * | |
602 | * It has 3 modes of operation: | |
603 | * - single: runs st->cb_state | |
604 | * - up: runs ++st->state, while st->state < st->target | |
605 | * - down: runs st->state--, while st->state > st->target | |
606 | * | |
607 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
608 | */ |
609 | static void cpuhp_thread_fun(unsigned int cpu) | |
610 | { | |
611 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
612 | bool bringup = st->bringup; |
613 | enum cpuhp_state state; | |
4cb28ced TG |
614 | |
615 | /* | |
4dddfb5f PZ |
616 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
617 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
618 | */ |
619 | smp_mb(); | |
4cb28ced | 620 | |
4dddfb5f PZ |
621 | if (WARN_ON_ONCE(!st->should_run)) |
622 | return; | |
4cb28ced | 623 | |
5f4b55e1 | 624 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 625 | |
a724632c | 626 | if (st->single) { |
4dddfb5f PZ |
627 | state = st->cb_state; |
628 | st->should_run = false; | |
629 | } else { | |
630 | if (bringup) { | |
631 | st->state++; | |
632 | state = st->state; | |
633 | st->should_run = (st->state < st->target); | |
634 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 635 | } else { |
4dddfb5f PZ |
636 | state = st->state; |
637 | st->state--; | |
638 | st->should_run = (st->state > st->target); | |
639 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 640 | } |
4dddfb5f PZ |
641 | } |
642 | ||
643 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
644 | ||
645 | if (st->rollback) { | |
646 | struct cpuhp_step *step = cpuhp_get_step(state); | |
647 | if (step->skip_onerr) | |
648 | goto next; | |
649 | } | |
650 | ||
651 | if (cpuhp_is_atomic_state(state)) { | |
652 | local_irq_disable(); | |
653 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
654 | local_irq_enable(); | |
3b9d6da6 | 655 | |
4dddfb5f PZ |
656 | /* |
657 | * STARTING/DYING must not fail! | |
658 | */ | |
659 | WARN_ON_ONCE(st->result); | |
4cb28ced | 660 | } else { |
4dddfb5f PZ |
661 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
662 | } | |
663 | ||
664 | if (st->result) { | |
665 | /* | |
666 | * If we fail on a rollback, we're up a creek without no | |
667 | * paddle, no way forward, no way back. We loose, thanks for | |
668 | * playing. | |
669 | */ | |
670 | WARN_ON_ONCE(st->rollback); | |
671 | st->should_run = false; | |
4cb28ced | 672 | } |
4dddfb5f PZ |
673 | |
674 | next: | |
5f4b55e1 | 675 | cpuhp_lock_release(bringup); |
4dddfb5f PZ |
676 | |
677 | if (!st->should_run) | |
5ebe7742 | 678 | complete_ap_thread(st, bringup); |
4cb28ced TG |
679 | } |
680 | ||
681 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 682 | static int |
cf392d10 TG |
683 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
684 | struct hlist_node *node) | |
4cb28ced TG |
685 | { |
686 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 687 | int ret; |
4cb28ced TG |
688 | |
689 | if (!cpu_online(cpu)) | |
690 | return 0; | |
691 | ||
5f4b55e1 PZ |
692 | cpuhp_lock_acquire(false); |
693 | cpuhp_lock_release(false); | |
694 | ||
695 | cpuhp_lock_acquire(true); | |
696 | cpuhp_lock_release(true); | |
49dfe2a6 | 697 | |
6a4e2451 TG |
698 | /* |
699 | * If we are up and running, use the hotplug thread. For early calls | |
700 | * we invoke the thread function directly. | |
701 | */ | |
702 | if (!st->thread) | |
96abb968 | 703 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 704 | |
4dddfb5f PZ |
705 | st->rollback = false; |
706 | st->last = NULL; | |
707 | ||
708 | st->node = node; | |
709 | st->bringup = bringup; | |
4cb28ced | 710 | st->cb_state = state; |
a724632c | 711 | st->single = true; |
a724632c | 712 | |
4dddfb5f | 713 | __cpuhp_kick_ap(st); |
4cb28ced | 714 | |
4cb28ced | 715 | /* |
4dddfb5f | 716 | * If we failed and did a partial, do a rollback. |
4cb28ced | 717 | */ |
4dddfb5f PZ |
718 | if ((ret = st->result) && st->last) { |
719 | st->rollback = true; | |
720 | st->bringup = !bringup; | |
721 | ||
722 | __cpuhp_kick_ap(st); | |
723 | } | |
724 | ||
1f7c70d6 TG |
725 | /* |
726 | * Clean up the leftovers so the next hotplug operation wont use stale | |
727 | * data. | |
728 | */ | |
729 | st->node = st->last = NULL; | |
4dddfb5f | 730 | return ret; |
1cf4f629 TG |
731 | } |
732 | ||
733 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
734 | { | |
735 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
736 | enum cpuhp_state prev_state = st->state; |
737 | int ret; | |
1cf4f629 | 738 | |
5f4b55e1 PZ |
739 | cpuhp_lock_acquire(false); |
740 | cpuhp_lock_release(false); | |
741 | ||
742 | cpuhp_lock_acquire(true); | |
743 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
744 | |
745 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
746 | ret = cpuhp_kick_ap(st, st->target); | |
747 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
748 | ||
749 | return ret; | |
4cb28ced TG |
750 | } |
751 | ||
752 | static struct smp_hotplug_thread cpuhp_threads = { | |
753 | .store = &cpuhp_state.thread, | |
754 | .create = &cpuhp_create, | |
755 | .thread_should_run = cpuhp_should_run, | |
756 | .thread_fn = cpuhp_thread_fun, | |
757 | .thread_comm = "cpuhp/%u", | |
758 | .selfparking = true, | |
759 | }; | |
760 | ||
761 | void __init cpuhp_threads_init(void) | |
762 | { | |
763 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
764 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
765 | } | |
766 | ||
777c6e0d | 767 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
768 | /** |
769 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
770 | * @cpu: a CPU id | |
771 | * | |
772 | * This function walks all processes, finds a valid mm struct for each one and | |
773 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
774 | * trivial, there are various non-obvious corner cases, which this function | |
775 | * tries to solve in a safe manner. | |
776 | * | |
777 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
778 | * be called only for an already offlined CPU. | |
779 | */ | |
cb79295e AV |
780 | void clear_tasks_mm_cpumask(int cpu) |
781 | { | |
782 | struct task_struct *p; | |
783 | ||
784 | /* | |
785 | * This function is called after the cpu is taken down and marked | |
786 | * offline, so its not like new tasks will ever get this cpu set in | |
787 | * their mm mask. -- Peter Zijlstra | |
788 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
789 | * full-fledged tasklist_lock. | |
790 | */ | |
e4cc2f87 | 791 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
792 | rcu_read_lock(); |
793 | for_each_process(p) { | |
794 | struct task_struct *t; | |
795 | ||
e4cc2f87 AV |
796 | /* |
797 | * Main thread might exit, but other threads may still have | |
798 | * a valid mm. Find one. | |
799 | */ | |
cb79295e AV |
800 | t = find_lock_task_mm(p); |
801 | if (!t) | |
802 | continue; | |
803 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
804 | task_unlock(t); | |
805 | } | |
806 | rcu_read_unlock(); | |
807 | } | |
808 | ||
1da177e4 | 809 | /* Take this CPU down. */ |
71cf5aee | 810 | static int take_cpu_down(void *_param) |
1da177e4 | 811 | { |
4baa0afc TG |
812 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
813 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 814 | int err, cpu = smp_processor_id(); |
724a8688 | 815 | int ret; |
1da177e4 | 816 | |
1da177e4 LT |
817 | /* Ensure this CPU doesn't handle any more interrupts. */ |
818 | err = __cpu_disable(); | |
819 | if (err < 0) | |
f3705136 | 820 | return err; |
1da177e4 | 821 | |
a724632c TG |
822 | /* |
823 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
824 | * do this step again. | |
825 | */ | |
826 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
827 | st->state--; | |
4baa0afc | 828 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
829 | for (; st->state > target; st->state--) { |
830 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
831 | /* | |
832 | * DYING must not fail! | |
833 | */ | |
834 | WARN_ON_ONCE(ret); | |
835 | } | |
4baa0afc | 836 | |
52c063d1 TG |
837 | /* Give up timekeeping duties */ |
838 | tick_handover_do_timer(); | |
14e568e7 | 839 | /* Park the stopper thread */ |
090e77c3 | 840 | stop_machine_park(cpu); |
f3705136 | 841 | return 0; |
1da177e4 LT |
842 | } |
843 | ||
98458172 | 844 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 845 | { |
e69aab13 | 846 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 847 | int err; |
1da177e4 | 848 | |
2a58c527 | 849 | /* Park the smpboot threads */ |
1cf4f629 TG |
850 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
851 | ||
6acce3ef | 852 | /* |
a8994181 TG |
853 | * Prevent irq alloc/free while the dying cpu reorganizes the |
854 | * interrupt affinities. | |
6acce3ef | 855 | */ |
a8994181 | 856 | irq_lock_sparse(); |
6acce3ef | 857 | |
a8994181 TG |
858 | /* |
859 | * So now all preempt/rcu users must observe !cpu_active(). | |
860 | */ | |
210e2133 | 861 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 862 | if (err) { |
3b9d6da6 | 863 | /* CPU refused to die */ |
a8994181 | 864 | irq_unlock_sparse(); |
3b9d6da6 SAS |
865 | /* Unpark the hotplug thread so we can rollback there */ |
866 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 867 | return err; |
8fa1d7d3 | 868 | } |
04321587 | 869 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 870 | |
48c5ccae | 871 | /* |
5b1ead68 BJ |
872 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
873 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 874 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
875 | * |
876 | * Wait for the stop thread to go away. | |
48c5ccae | 877 | */ |
5ebe7742 | 878 | wait_for_ap_thread(st, false); |
e69aab13 | 879 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 880 | |
a8994181 TG |
881 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
882 | irq_unlock_sparse(); | |
883 | ||
345527b1 | 884 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
885 | /* This actually kills the CPU. */ |
886 | __cpu_die(cpu); | |
887 | ||
a49b116d | 888 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 889 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
890 | return 0; |
891 | } | |
1da177e4 | 892 | |
71f87b2f TG |
893 | static void cpuhp_complete_idle_dead(void *arg) |
894 | { | |
895 | struct cpuhp_cpu_state *st = arg; | |
896 | ||
5ebe7742 | 897 | complete_ap_thread(st, false); |
71f87b2f TG |
898 | } |
899 | ||
e69aab13 TG |
900 | void cpuhp_report_idle_dead(void) |
901 | { | |
902 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
903 | ||
904 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 905 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
906 | st->state = CPUHP_AP_IDLE_DEAD; |
907 | /* | |
908 | * We cannot call complete after rcu_report_dead() so we delegate it | |
909 | * to an online cpu. | |
910 | */ | |
911 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
912 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
913 | } |
914 | ||
4dddfb5f PZ |
915 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
916 | { | |
917 | for (st->state++; st->state < st->target; st->state++) { | |
918 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
cff7d378 | 919 | |
4dddfb5f PZ |
920 | if (!step->skip_onerr) |
921 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
922 | } | |
923 | } | |
924 | ||
925 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
926 | enum cpuhp_state target) | |
927 | { | |
928 | enum cpuhp_state prev_state = st->state; | |
929 | int ret = 0; | |
930 | ||
931 | for (; st->state > target; st->state--) { | |
932 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
933 | if (ret) { | |
934 | st->target = prev_state; | |
935 | undo_cpu_down(cpu, st); | |
936 | break; | |
937 | } | |
938 | } | |
939 | return ret; | |
940 | } | |
cff7d378 | 941 | |
98458172 | 942 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
943 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
944 | enum cpuhp_state target) | |
98458172 | 945 | { |
cff7d378 TG |
946 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
947 | int prev_state, ret = 0; | |
98458172 TG |
948 | |
949 | if (num_online_cpus() == 1) | |
950 | return -EBUSY; | |
951 | ||
757c989b | 952 | if (!cpu_present(cpu)) |
98458172 TG |
953 | return -EINVAL; |
954 | ||
8f553c49 | 955 | cpus_write_lock(); |
98458172 TG |
956 | |
957 | cpuhp_tasks_frozen = tasks_frozen; | |
958 | ||
4dddfb5f | 959 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
960 | /* |
961 | * If the current CPU state is in the range of the AP hotplug thread, | |
962 | * then we need to kick the thread. | |
963 | */ | |
8df3e07e | 964 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 965 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
966 | ret = cpuhp_kick_ap_work(cpu); |
967 | /* | |
968 | * The AP side has done the error rollback already. Just | |
969 | * return the error code.. | |
970 | */ | |
971 | if (ret) | |
972 | goto out; | |
973 | ||
974 | /* | |
975 | * We might have stopped still in the range of the AP hotplug | |
976 | * thread. Nothing to do anymore. | |
977 | */ | |
8df3e07e | 978 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 979 | goto out; |
4dddfb5f PZ |
980 | |
981 | st->target = target; | |
1cf4f629 TG |
982 | } |
983 | /* | |
8df3e07e | 984 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
985 | * to do the further cleanups. |
986 | */ | |
a724632c | 987 | ret = cpuhp_down_callbacks(cpu, st, target); |
3b9d6da6 | 988 | if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
989 | cpuhp_reset_state(st, prev_state); |
990 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 991 | } |
98458172 | 992 | |
1cf4f629 | 993 | out: |
8f553c49 | 994 | cpus_write_unlock(); |
941154bd TG |
995 | /* |
996 | * Do post unplug cleanup. This is still protected against | |
997 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
998 | */ | |
999 | lockup_detector_cleanup(); | |
cff7d378 | 1000 | return ret; |
e3920fb4 RW |
1001 | } |
1002 | ||
97127f50 TG |
1003 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1004 | { | |
1005 | if (cpu_hotplug_disabled) | |
1006 | return -EBUSY; | |
1007 | return _cpu_down(cpu, 0, target); | |
1008 | } | |
1009 | ||
af1f4045 | 1010 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1011 | { |
9ea09af3 | 1012 | int err; |
e3920fb4 | 1013 | |
d221938c | 1014 | cpu_maps_update_begin(); |
97127f50 | 1015 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1016 | cpu_maps_update_done(); |
1da177e4 LT |
1017 | return err; |
1018 | } | |
4dddfb5f | 1019 | |
af1f4045 TG |
1020 | int cpu_down(unsigned int cpu) |
1021 | { | |
1022 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1023 | } | |
b62b8ef9 | 1024 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f PZ |
1025 | |
1026 | #else | |
1027 | #define takedown_cpu NULL | |
1da177e4 LT |
1028 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1029 | ||
4baa0afc | 1030 | /** |
ee1e714b | 1031 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1032 | * @cpu: cpu that just started |
1033 | * | |
4baa0afc TG |
1034 | * It must be called by the arch code on the new cpu, before the new cpu |
1035 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1036 | */ | |
1037 | void notify_cpu_starting(unsigned int cpu) | |
1038 | { | |
1039 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1040 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1041 | int ret; |
4baa0afc | 1042 | |
0c6d4576 | 1043 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
3762ba90 | 1044 | st->booted_once = true; |
4baa0afc | 1045 | while (st->state < target) { |
4baa0afc | 1046 | st->state++; |
724a8688 PZ |
1047 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1048 | /* | |
1049 | * STARTING must not fail! | |
1050 | */ | |
1051 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1052 | } |
1053 | } | |
1054 | ||
949338e3 | 1055 | /* |
9cd4f1a4 TG |
1056 | * Called from the idle task. Wake up the controlling task which brings the |
1057 | * stopper and the hotplug thread of the upcoming CPU up and then delegates | |
1058 | * the rest of the online bringup to the hotplug thread. | |
949338e3 | 1059 | */ |
8df3e07e | 1060 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1061 | { |
8df3e07e | 1062 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1063 | |
1064 | /* Happens for the boot cpu */ | |
1065 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1066 | return; | |
1067 | ||
1068 | st->state = CPUHP_AP_ONLINE_IDLE; | |
5ebe7742 | 1069 | complete_ap_thread(st, true); |
949338e3 TG |
1070 | } |
1071 | ||
e3920fb4 | 1072 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1073 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1074 | { |
cff7d378 | 1075 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1076 | struct task_struct *idle; |
2e1a3483 | 1077 | int ret = 0; |
1da177e4 | 1078 | |
8f553c49 | 1079 | cpus_write_lock(); |
38498a67 | 1080 | |
757c989b | 1081 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1082 | ret = -EINVAL; |
1083 | goto out; | |
1084 | } | |
1085 | ||
757c989b TG |
1086 | /* |
1087 | * The caller of do_cpu_up might have raced with another | |
1088 | * caller. Ignore it for now. | |
1089 | */ | |
1090 | if (st->state >= target) | |
38498a67 | 1091 | goto out; |
757c989b TG |
1092 | |
1093 | if (st->state == CPUHP_OFFLINE) { | |
1094 | /* Let it fail before we try to bring the cpu up */ | |
1095 | idle = idle_thread_get(cpu); | |
1096 | if (IS_ERR(idle)) { | |
1097 | ret = PTR_ERR(idle); | |
1098 | goto out; | |
1099 | } | |
3bb5d2ee | 1100 | } |
38498a67 | 1101 | |
ba997462 TG |
1102 | cpuhp_tasks_frozen = tasks_frozen; |
1103 | ||
4dddfb5f | 1104 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1105 | /* |
1106 | * If the current CPU state is in the range of the AP hotplug thread, | |
1107 | * then we need to kick the thread once more. | |
1108 | */ | |
8df3e07e | 1109 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1110 | ret = cpuhp_kick_ap_work(cpu); |
1111 | /* | |
1112 | * The AP side has done the error rollback already. Just | |
1113 | * return the error code.. | |
1114 | */ | |
1115 | if (ret) | |
1116 | goto out; | |
1117 | } | |
1118 | ||
1119 | /* | |
1120 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1121 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1122 | * responsible for bringing it up to the target state. |
1123 | */ | |
8df3e07e | 1124 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1125 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1126 | out: |
8f553c49 | 1127 | cpus_write_unlock(); |
e3920fb4 RW |
1128 | return ret; |
1129 | } | |
1130 | ||
af1f4045 | 1131 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1132 | { |
1133 | int err = 0; | |
cf23422b | 1134 | |
e0b582ec | 1135 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1136 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1137 | cpu); | |
87d5e023 | 1138 | #if defined(CONFIG_IA64) |
84117da5 | 1139 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1140 | #endif |
1141 | return -EINVAL; | |
1142 | } | |
e3920fb4 | 1143 | |
01b0f197 TK |
1144 | err = try_online_node(cpu_to_node(cpu)); |
1145 | if (err) | |
1146 | return err; | |
cf23422b | 1147 | |
d221938c | 1148 | cpu_maps_update_begin(); |
e761b772 MK |
1149 | |
1150 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1151 | err = -EBUSY; |
e761b772 MK |
1152 | goto out; |
1153 | } | |
47b4c679 TG |
1154 | if (!cpu_smt_allowed(cpu)) { |
1155 | err = -EPERM; | |
1156 | goto out; | |
1157 | } | |
e761b772 | 1158 | |
af1f4045 | 1159 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1160 | out: |
d221938c | 1161 | cpu_maps_update_done(); |
e3920fb4 RW |
1162 | return err; |
1163 | } | |
af1f4045 TG |
1164 | |
1165 | int cpu_up(unsigned int cpu) | |
1166 | { | |
1167 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1168 | } | |
a513f6ba | 1169 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1170 | |
f3de4be9 | 1171 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1172 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1173 | |
d391e552 | 1174 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1175 | { |
d391e552 | 1176 | int cpu, error = 0; |
e3920fb4 | 1177 | |
d221938c | 1178 | cpu_maps_update_begin(); |
d391e552 JM |
1179 | if (!cpu_online(primary)) |
1180 | primary = cpumask_first(cpu_online_mask); | |
9ee349ad XF |
1181 | /* |
1182 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1183 | * with the userspace trying to use the CPU hotplug at the same time |
1184 | */ | |
e0b582ec | 1185 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1186 | |
84117da5 | 1187 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1188 | for_each_online_cpu(cpu) { |
d391e552 | 1189 | if (cpu == primary) |
e3920fb4 | 1190 | continue; |
bb3632c6 | 1191 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1192 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1193 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1194 | if (!error) |
e0b582ec | 1195 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1196 | else { |
84117da5 | 1197 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1198 | break; |
1199 | } | |
1200 | } | |
86886e55 | 1201 | |
89af7ba5 | 1202 | if (!error) |
e3920fb4 | 1203 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1204 | else |
84117da5 | 1205 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1206 | |
1207 | /* | |
1208 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1209 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1210 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1211 | */ | |
1212 | cpu_hotplug_disabled++; | |
1213 | ||
d221938c | 1214 | cpu_maps_update_done(); |
e3920fb4 RW |
1215 | return error; |
1216 | } | |
1217 | ||
d0af9eed SS |
1218 | void __weak arch_enable_nonboot_cpus_begin(void) |
1219 | { | |
1220 | } | |
1221 | ||
1222 | void __weak arch_enable_nonboot_cpus_end(void) | |
1223 | { | |
1224 | } | |
1225 | ||
71cf5aee | 1226 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1227 | { |
1228 | int cpu, error; | |
1229 | ||
1230 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1231 | cpu_maps_update_begin(); |
01b41159 | 1232 | __cpu_hotplug_enable(); |
e0b582ec | 1233 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1234 | goto out; |
e3920fb4 | 1235 | |
84117da5 | 1236 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1237 | |
1238 | arch_enable_nonboot_cpus_begin(); | |
1239 | ||
e0b582ec | 1240 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1241 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1242 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1243 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1244 | if (!error) { |
84117da5 | 1245 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1246 | continue; |
1247 | } | |
84117da5 | 1248 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1249 | } |
d0af9eed SS |
1250 | |
1251 | arch_enable_nonboot_cpus_end(); | |
1252 | ||
e0b582ec | 1253 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1254 | out: |
d221938c | 1255 | cpu_maps_update_done(); |
1da177e4 | 1256 | } |
e0b582ec | 1257 | |
d7268a31 | 1258 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1259 | { |
1260 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1261 | return -ENOMEM; | |
1262 | return 0; | |
1263 | } | |
1264 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1265 | |
79cfbdfa SB |
1266 | /* |
1267 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1268 | * ensure that the state of the system with respect to the tasks being frozen | |
1269 | * or not, as reported by the notification, remains unchanged *throughout the | |
1270 | * duration* of the execution of the callbacks. | |
1271 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1272 | * | |
1273 | * This synchronization is implemented by mutually excluding regular CPU | |
1274 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1275 | * Hibernate notifications. | |
1276 | */ | |
1277 | static int | |
1278 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1279 | unsigned long action, void *ptr) | |
1280 | { | |
1281 | switch (action) { | |
1282 | ||
1283 | case PM_SUSPEND_PREPARE: | |
1284 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1285 | cpu_hotplug_disable(); |
79cfbdfa SB |
1286 | break; |
1287 | ||
1288 | case PM_POST_SUSPEND: | |
1289 | case PM_POST_HIBERNATION: | |
16e53dbf | 1290 | cpu_hotplug_enable(); |
79cfbdfa SB |
1291 | break; |
1292 | ||
1293 | default: | |
1294 | return NOTIFY_DONE; | |
1295 | } | |
1296 | ||
1297 | return NOTIFY_OK; | |
1298 | } | |
1299 | ||
1300 | ||
d7268a31 | 1301 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1302 | { |
6e32d479 FY |
1303 | /* |
1304 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1305 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1306 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1307 | */ | |
79cfbdfa SB |
1308 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1309 | return 0; | |
1310 | } | |
1311 | core_initcall(cpu_hotplug_pm_sync_init); | |
1312 | ||
f3de4be9 | 1313 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1314 | |
8ce371f9 PZ |
1315 | int __boot_cpu_id; |
1316 | ||
68f4f1ec | 1317 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1318 | |
cff7d378 TG |
1319 | /* Boot processor state steps */ |
1320 | static struct cpuhp_step cpuhp_bp_states[] = { | |
1321 | [CPUHP_OFFLINE] = { | |
1322 | .name = "offline", | |
3c1627e9 TG |
1323 | .startup.single = NULL, |
1324 | .teardown.single = NULL, | |
cff7d378 TG |
1325 | }, |
1326 | #ifdef CONFIG_SMP | |
1327 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1328 | .name = "threads:prepare", |
3c1627e9 TG |
1329 | .startup.single = smpboot_create_threads, |
1330 | .teardown.single = NULL, | |
757c989b | 1331 | .cant_stop = true, |
cff7d378 | 1332 | }, |
00e16c3d | 1333 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1334 | .name = "perf:prepare", |
1335 | .startup.single = perf_event_init_cpu, | |
1336 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1337 | }, |
7ee681b2 | 1338 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1339 | .name = "workqueue:prepare", |
1340 | .startup.single = workqueue_prepare_cpu, | |
1341 | .teardown.single = NULL, | |
7ee681b2 | 1342 | }, |
27590dc1 | 1343 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1344 | .name = "hrtimers:prepare", |
1345 | .startup.single = hrtimers_prepare_cpu, | |
1346 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1347 | }, |
31487f83 | 1348 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1349 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1350 | .startup.single = smpcfd_prepare_cpu, |
1351 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1352 | }, |
e6d4989a RW |
1353 | [CPUHP_RELAY_PREPARE] = { |
1354 | .name = "relay:prepare", | |
1355 | .startup.single = relay_prepare_cpu, | |
1356 | .teardown.single = NULL, | |
1357 | }, | |
6731d4f1 SAS |
1358 | [CPUHP_SLAB_PREPARE] = { |
1359 | .name = "slab:prepare", | |
1360 | .startup.single = slab_prepare_cpu, | |
1361 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1362 | }, |
4df83742 | 1363 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1364 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1365 | .startup.single = rcutree_prepare_cpu, |
1366 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1367 | }, |
4fae16df RC |
1368 | /* |
1369 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1370 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1371 | * otherwise a RCU stall occurs. | |
1372 | */ | |
26456f87 | 1373 | [CPUHP_TIMERS_PREPARE] = { |
3c1627e9 | 1374 | .name = "timers:dead", |
26456f87 | 1375 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1376 | .teardown.single = timers_dead_cpu, |
4fae16df | 1377 | }, |
d10ef6f9 | 1378 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1379 | [CPUHP_BRINGUP_CPU] = { |
1380 | .name = "cpu:bringup", | |
3c1627e9 TG |
1381 | .startup.single = bringup_cpu, |
1382 | .teardown.single = NULL, | |
757c989b | 1383 | .cant_stop = true, |
4baa0afc | 1384 | }, |
d10ef6f9 TG |
1385 | /* |
1386 | * Handled on controll processor until the plugged processor manages | |
1387 | * this itself. | |
1388 | */ | |
4baa0afc TG |
1389 | [CPUHP_TEARDOWN_CPU] = { |
1390 | .name = "cpu:teardown", | |
3c1627e9 TG |
1391 | .startup.single = NULL, |
1392 | .teardown.single = takedown_cpu, | |
757c989b | 1393 | .cant_stop = true, |
cff7d378 | 1394 | }, |
a7c73414 TG |
1395 | #else |
1396 | [CPUHP_BRINGUP_CPU] = { }, | |
cff7d378 | 1397 | #endif |
cff7d378 TG |
1398 | }; |
1399 | ||
4baa0afc TG |
1400 | /* Application processor state steps */ |
1401 | static struct cpuhp_step cpuhp_ap_states[] = { | |
1402 | #ifdef CONFIG_SMP | |
d10ef6f9 TG |
1403 | /* Final state before CPU kills itself */ |
1404 | [CPUHP_AP_IDLE_DEAD] = { | |
1405 | .name = "idle:dead", | |
1406 | }, | |
1407 | /* | |
1408 | * Last state before CPU enters the idle loop to die. Transient state | |
1409 | * for synchronization. | |
1410 | */ | |
1411 | [CPUHP_AP_OFFLINE] = { | |
1412 | .name = "ap:offline", | |
1413 | .cant_stop = true, | |
1414 | }, | |
9cf7243d TG |
1415 | /* First state is scheduler control. Interrupts are disabled */ |
1416 | [CPUHP_AP_SCHED_STARTING] = { | |
1417 | .name = "sched:starting", | |
3c1627e9 TG |
1418 | .startup.single = sched_cpu_starting, |
1419 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1420 | }, |
4df83742 | 1421 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1422 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1423 | .startup.single = NULL, |
1424 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1425 | }, |
46febd37 LJ |
1426 | [CPUHP_AP_SMPCFD_DYING] = { |
1427 | .name = "smpcfd:dying", | |
1428 | .startup.single = NULL, | |
1429 | .teardown.single = smpcfd_dying_cpu, | |
1430 | }, | |
d10ef6f9 TG |
1431 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1432 | * state for synchronsization */ | |
1433 | [CPUHP_AP_ONLINE] = { | |
1434 | .name = "ap:online", | |
1435 | }, | |
1436 | /* Handle smpboot threads park/unpark */ | |
1cf4f629 | 1437 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1438 | .name = "smpboot/threads:online", |
3c1627e9 | 1439 | .startup.single = smpboot_unpark_threads, |
a82cd3a3 | 1440 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1441 | }, |
c5cb83bb TG |
1442 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1443 | .name = "irq/affinity:online", | |
1444 | .startup.single = irq_affinity_online_cpu, | |
1445 | .teardown.single = NULL, | |
1446 | }, | |
00e16c3d | 1447 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1448 | .name = "perf:online", |
1449 | .startup.single = perf_event_init_cpu, | |
1450 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1451 | }, |
7ee681b2 | 1452 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1453 | .name = "workqueue:online", |
1454 | .startup.single = workqueue_online_cpu, | |
1455 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1456 | }, |
4df83742 | 1457 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1458 | .name = "RCU/tree:online", |
3c1627e9 TG |
1459 | .startup.single = rcutree_online_cpu, |
1460 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1461 | }, |
4baa0afc | 1462 | #endif |
d10ef6f9 TG |
1463 | /* |
1464 | * The dynamically registered state space is here | |
1465 | */ | |
1466 | ||
aaddd7d1 TG |
1467 | #ifdef CONFIG_SMP |
1468 | /* Last state is scheduler control setting the cpu active */ | |
1469 | [CPUHP_AP_ACTIVE] = { | |
1470 | .name = "sched:active", | |
3c1627e9 TG |
1471 | .startup.single = sched_cpu_activate, |
1472 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1473 | }, |
1474 | #endif | |
1475 | ||
d10ef6f9 | 1476 | /* CPU is fully up and running. */ |
4baa0afc TG |
1477 | [CPUHP_ONLINE] = { |
1478 | .name = "online", | |
3c1627e9 TG |
1479 | .startup.single = NULL, |
1480 | .teardown.single = NULL, | |
4baa0afc TG |
1481 | }, |
1482 | }; | |
1483 | ||
5b7aa87e TG |
1484 | /* Sanity check for callbacks */ |
1485 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1486 | { | |
1487 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1488 | return -EINVAL; | |
1489 | return 0; | |
1490 | } | |
1491 | ||
dc280d93 TG |
1492 | /* |
1493 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1494 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1495 | * by having no name assigned. | |
1496 | */ | |
1497 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1498 | { | |
4205e478 TG |
1499 | enum cpuhp_state i, end; |
1500 | struct cpuhp_step *step; | |
dc280d93 | 1501 | |
4205e478 TG |
1502 | switch (state) { |
1503 | case CPUHP_AP_ONLINE_DYN: | |
1504 | step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN; | |
1505 | end = CPUHP_AP_ONLINE_DYN_END; | |
1506 | break; | |
1507 | case CPUHP_BP_PREPARE_DYN: | |
1508 | step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN; | |
1509 | end = CPUHP_BP_PREPARE_DYN_END; | |
1510 | break; | |
1511 | default: | |
1512 | return -EINVAL; | |
1513 | } | |
1514 | ||
1515 | for (i = state; i <= end; i++, step++) { | |
1516 | if (!step->name) | |
dc280d93 TG |
1517 | return i; |
1518 | } | |
1519 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1520 | return -ENOSPC; | |
1521 | } | |
1522 | ||
1523 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1524 | int (*startup)(unsigned int cpu), | |
1525 | int (*teardown)(unsigned int cpu), | |
1526 | bool multi_instance) | |
5b7aa87e TG |
1527 | { |
1528 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1529 | struct cpuhp_step *sp; | |
dc280d93 | 1530 | int ret = 0; |
5b7aa87e | 1531 | |
0c96b273 EB |
1532 | /* |
1533 | * If name is NULL, then the state gets removed. | |
1534 | * | |
1535 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1536 | * the first allocation from these dynamic ranges, so the removal | |
1537 | * would trigger a new allocation and clear the wrong (already | |
1538 | * empty) state, leaving the callbacks of the to be cleared state | |
1539 | * dangling, which causes wreckage on the next hotplug operation. | |
1540 | */ | |
1541 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1542 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1543 | ret = cpuhp_reserve_state(state); |
1544 | if (ret < 0) | |
dc434e05 | 1545 | return ret; |
dc280d93 TG |
1546 | state = ret; |
1547 | } | |
5b7aa87e | 1548 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1549 | if (name && sp->name) |
1550 | return -EBUSY; | |
1551 | ||
3c1627e9 TG |
1552 | sp->startup.single = startup; |
1553 | sp->teardown.single = teardown; | |
5b7aa87e | 1554 | sp->name = name; |
cf392d10 TG |
1555 | sp->multi_instance = multi_instance; |
1556 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1557 | return ret; |
5b7aa87e TG |
1558 | } |
1559 | ||
1560 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1561 | { | |
3c1627e9 | 1562 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1563 | } |
1564 | ||
5b7aa87e TG |
1565 | /* |
1566 | * Call the startup/teardown function for a step either on the AP or | |
1567 | * on the current CPU. | |
1568 | */ | |
cf392d10 TG |
1569 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1570 | struct hlist_node *node) | |
5b7aa87e | 1571 | { |
a724632c | 1572 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1573 | int ret; |
1574 | ||
4dddfb5f PZ |
1575 | /* |
1576 | * If there's nothing to do, we done. | |
1577 | * Relies on the union for multi_instance. | |
1578 | */ | |
3c1627e9 TG |
1579 | if ((bringup && !sp->startup.single) || |
1580 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1581 | return 0; |
5b7aa87e TG |
1582 | /* |
1583 | * The non AP bound callbacks can fail on bringup. On teardown | |
1584 | * e.g. module removal we crash for now. | |
1585 | */ | |
1cf4f629 TG |
1586 | #ifdef CONFIG_SMP |
1587 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1588 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1589 | else |
96abb968 | 1590 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1591 | #else |
96abb968 | 1592 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1593 | #endif |
5b7aa87e TG |
1594 | BUG_ON(ret && !bringup); |
1595 | return ret; | |
1596 | } | |
1597 | ||
1598 | /* | |
1599 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1600 | * | |
1601 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1602 | */ | |
1603 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1604 | struct hlist_node *node) |
5b7aa87e TG |
1605 | { |
1606 | int cpu; | |
1607 | ||
5b7aa87e TG |
1608 | /* Roll back the already executed steps on the other cpus */ |
1609 | for_each_present_cpu(cpu) { | |
1610 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1611 | int cpustate = st->state; | |
1612 | ||
1613 | if (cpu >= failedcpu) | |
1614 | break; | |
1615 | ||
1616 | /* Did we invoke the startup call on that cpu ? */ | |
1617 | if (cpustate >= state) | |
cf392d10 | 1618 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1619 | } |
1620 | } | |
1621 | ||
9805c673 TG |
1622 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1623 | struct hlist_node *node, | |
1624 | bool invoke) | |
cf392d10 TG |
1625 | { |
1626 | struct cpuhp_step *sp; | |
1627 | int cpu; | |
1628 | int ret; | |
1629 | ||
9805c673 TG |
1630 | lockdep_assert_cpus_held(); |
1631 | ||
cf392d10 TG |
1632 | sp = cpuhp_get_step(state); |
1633 | if (sp->multi_instance == false) | |
1634 | return -EINVAL; | |
1635 | ||
dc434e05 | 1636 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1637 | |
3c1627e9 | 1638 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1639 | goto add_node; |
1640 | ||
1641 | /* | |
1642 | * Try to call the startup callback for each present cpu | |
1643 | * depending on the hotplug state of the cpu. | |
1644 | */ | |
1645 | for_each_present_cpu(cpu) { | |
1646 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1647 | int cpustate = st->state; | |
1648 | ||
1649 | if (cpustate < state) | |
1650 | continue; | |
1651 | ||
1652 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1653 | if (ret) { | |
3c1627e9 | 1654 | if (sp->teardown.multi) |
cf392d10 | 1655 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1656 | goto unlock; |
cf392d10 TG |
1657 | } |
1658 | } | |
1659 | add_node: | |
1660 | ret = 0; | |
cf392d10 | 1661 | hlist_add_head(node, &sp->list); |
dc434e05 | 1662 | unlock: |
cf392d10 | 1663 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1664 | return ret; |
1665 | } | |
1666 | ||
1667 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1668 | bool invoke) | |
1669 | { | |
1670 | int ret; | |
1671 | ||
1672 | cpus_read_lock(); | |
1673 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1674 | cpus_read_unlock(); |
cf392d10 TG |
1675 | return ret; |
1676 | } | |
1677 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1678 | ||
5b7aa87e | 1679 | /** |
71def423 | 1680 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1681 | * @state: The state to setup |
1682 | * @invoke: If true, the startup function is invoked for cpus where | |
1683 | * cpu state >= @state | |
1684 | * @startup: startup callback function | |
1685 | * @teardown: teardown callback function | |
1686 | * @multi_instance: State is set up for multiple instances which get | |
1687 | * added afterwards. | |
5b7aa87e | 1688 | * |
71def423 | 1689 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1690 | * Returns: |
1691 | * On success: | |
1692 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1693 | * 0 for all other states | |
1694 | * On failure: proper (negative) error code | |
5b7aa87e | 1695 | */ |
71def423 SAS |
1696 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1697 | const char *name, bool invoke, | |
1698 | int (*startup)(unsigned int cpu), | |
1699 | int (*teardown)(unsigned int cpu), | |
1700 | bool multi_instance) | |
5b7aa87e TG |
1701 | { |
1702 | int cpu, ret = 0; | |
b9d9d691 | 1703 | bool dynstate; |
5b7aa87e | 1704 | |
71def423 SAS |
1705 | lockdep_assert_cpus_held(); |
1706 | ||
5b7aa87e TG |
1707 | if (cpuhp_cb_check(state) || !name) |
1708 | return -EINVAL; | |
1709 | ||
dc434e05 | 1710 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1711 | |
dc280d93 TG |
1712 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1713 | multi_instance); | |
5b7aa87e | 1714 | |
b9d9d691 TG |
1715 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1716 | if (ret > 0 && dynstate) { | |
1717 | state = ret; | |
1718 | ret = 0; | |
1719 | } | |
1720 | ||
dc280d93 | 1721 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1722 | goto out; |
1723 | ||
1724 | /* | |
1725 | * Try to call the startup callback for each present cpu | |
1726 | * depending on the hotplug state of the cpu. | |
1727 | */ | |
1728 | for_each_present_cpu(cpu) { | |
1729 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1730 | int cpustate = st->state; | |
1731 | ||
1732 | if (cpustate < state) | |
1733 | continue; | |
1734 | ||
cf392d10 | 1735 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1736 | if (ret) { |
a724632c | 1737 | if (teardown) |
cf392d10 TG |
1738 | cpuhp_rollback_install(cpu, state, NULL); |
1739 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1740 | goto out; |
1741 | } | |
1742 | } | |
1743 | out: | |
dc434e05 | 1744 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1745 | /* |
1746 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1747 | * dynamically allocated state in case of success. | |
1748 | */ | |
b9d9d691 | 1749 | if (!ret && dynstate) |
5b7aa87e TG |
1750 | return state; |
1751 | return ret; | |
1752 | } | |
71def423 SAS |
1753 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1754 | ||
1755 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1756 | const char *name, bool invoke, | |
1757 | int (*startup)(unsigned int cpu), | |
1758 | int (*teardown)(unsigned int cpu), | |
1759 | bool multi_instance) | |
1760 | { | |
1761 | int ret; | |
1762 | ||
1763 | cpus_read_lock(); | |
1764 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1765 | teardown, multi_instance); | |
1766 | cpus_read_unlock(); | |
1767 | return ret; | |
1768 | } | |
5b7aa87e TG |
1769 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1770 | ||
cf392d10 TG |
1771 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1772 | struct hlist_node *node, bool invoke) | |
1773 | { | |
1774 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1775 | int cpu; | |
1776 | ||
1777 | BUG_ON(cpuhp_cb_check(state)); | |
1778 | ||
1779 | if (!sp->multi_instance) | |
1780 | return -EINVAL; | |
1781 | ||
8f553c49 | 1782 | cpus_read_lock(); |
dc434e05 SAS |
1783 | mutex_lock(&cpuhp_state_mutex); |
1784 | ||
cf392d10 TG |
1785 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1786 | goto remove; | |
1787 | /* | |
1788 | * Call the teardown callback for each present cpu depending | |
1789 | * on the hotplug state of the cpu. This function is not | |
1790 | * allowed to fail currently! | |
1791 | */ | |
1792 | for_each_present_cpu(cpu) { | |
1793 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1794 | int cpustate = st->state; | |
1795 | ||
1796 | if (cpustate >= state) | |
1797 | cpuhp_issue_call(cpu, state, false, node); | |
1798 | } | |
1799 | ||
1800 | remove: | |
cf392d10 TG |
1801 | hlist_del(node); |
1802 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1803 | cpus_read_unlock(); |
cf392d10 TG |
1804 | |
1805 | return 0; | |
1806 | } | |
1807 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1808 | |
5b7aa87e | 1809 | /** |
71def423 | 1810 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1811 | * @state: The state to remove |
1812 | * @invoke: If true, the teardown function is invoked for cpus where | |
1813 | * cpu state >= @state | |
1814 | * | |
71def423 | 1815 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1816 | * The teardown callback is currently not allowed to fail. Think |
1817 | * about module removal! | |
1818 | */ | |
71def423 | 1819 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1820 | { |
cf392d10 | 1821 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1822 | int cpu; |
1823 | ||
1824 | BUG_ON(cpuhp_cb_check(state)); | |
1825 | ||
71def423 | 1826 | lockdep_assert_cpus_held(); |
5b7aa87e | 1827 | |
dc434e05 | 1828 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1829 | if (sp->multi_instance) { |
1830 | WARN(!hlist_empty(&sp->list), | |
1831 | "Error: Removing state %d which has instances left.\n", | |
1832 | state); | |
1833 | goto remove; | |
1834 | } | |
1835 | ||
a724632c | 1836 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1837 | goto remove; |
1838 | ||
1839 | /* | |
1840 | * Call the teardown callback for each present cpu depending | |
1841 | * on the hotplug state of the cpu. This function is not | |
1842 | * allowed to fail currently! | |
1843 | */ | |
1844 | for_each_present_cpu(cpu) { | |
1845 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1846 | int cpustate = st->state; | |
1847 | ||
1848 | if (cpustate >= state) | |
cf392d10 | 1849 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1850 | } |
1851 | remove: | |
cf392d10 | 1852 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1853 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1854 | } |
1855 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1856 | ||
1857 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1858 | { | |
1859 | cpus_read_lock(); | |
1860 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 1861 | cpus_read_unlock(); |
5b7aa87e TG |
1862 | } |
1863 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1864 | ||
98f8cdce TG |
1865 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1866 | static ssize_t show_cpuhp_state(struct device *dev, | |
1867 | struct device_attribute *attr, char *buf) | |
1868 | { | |
1869 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1870 | ||
1871 | return sprintf(buf, "%d\n", st->state); | |
1872 | } | |
1873 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1874 | ||
757c989b TG |
1875 | static ssize_t write_cpuhp_target(struct device *dev, |
1876 | struct device_attribute *attr, | |
1877 | const char *buf, size_t count) | |
1878 | { | |
1879 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1880 | struct cpuhp_step *sp; | |
1881 | int target, ret; | |
1882 | ||
1883 | ret = kstrtoint(buf, 10, &target); | |
1884 | if (ret) | |
1885 | return ret; | |
1886 | ||
1887 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1888 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1889 | return -EINVAL; | |
1890 | #else | |
1891 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1892 | return -EINVAL; | |
1893 | #endif | |
1894 | ||
1895 | ret = lock_device_hotplug_sysfs(); | |
1896 | if (ret) | |
1897 | return ret; | |
1898 | ||
1899 | mutex_lock(&cpuhp_state_mutex); | |
1900 | sp = cpuhp_get_step(target); | |
1901 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1902 | mutex_unlock(&cpuhp_state_mutex); | |
1903 | if (ret) | |
40da1b11 | 1904 | goto out; |
757c989b TG |
1905 | |
1906 | if (st->state < target) | |
1907 | ret = do_cpu_up(dev->id, target); | |
1908 | else | |
1909 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 1910 | out: |
757c989b TG |
1911 | unlock_device_hotplug(); |
1912 | return ret ? ret : count; | |
1913 | } | |
1914 | ||
98f8cdce TG |
1915 | static ssize_t show_cpuhp_target(struct device *dev, |
1916 | struct device_attribute *attr, char *buf) | |
1917 | { | |
1918 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1919 | ||
1920 | return sprintf(buf, "%d\n", st->target); | |
1921 | } | |
757c989b | 1922 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 1923 | |
1db49484 PZ |
1924 | |
1925 | static ssize_t write_cpuhp_fail(struct device *dev, | |
1926 | struct device_attribute *attr, | |
1927 | const char *buf, size_t count) | |
1928 | { | |
1929 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1930 | struct cpuhp_step *sp; | |
1931 | int fail, ret; | |
1932 | ||
1933 | ret = kstrtoint(buf, 10, &fail); | |
1934 | if (ret) | |
1935 | return ret; | |
1936 | ||
1937 | /* | |
1938 | * Cannot fail STARTING/DYING callbacks. | |
1939 | */ | |
1940 | if (cpuhp_is_atomic_state(fail)) | |
1941 | return -EINVAL; | |
1942 | ||
1943 | /* | |
1944 | * Cannot fail anything that doesn't have callbacks. | |
1945 | */ | |
1946 | mutex_lock(&cpuhp_state_mutex); | |
1947 | sp = cpuhp_get_step(fail); | |
1948 | if (!sp->startup.single && !sp->teardown.single) | |
1949 | ret = -EINVAL; | |
1950 | mutex_unlock(&cpuhp_state_mutex); | |
1951 | if (ret) | |
1952 | return ret; | |
1953 | ||
1954 | st->fail = fail; | |
1955 | ||
1956 | return count; | |
1957 | } | |
1958 | ||
1959 | static ssize_t show_cpuhp_fail(struct device *dev, | |
1960 | struct device_attribute *attr, char *buf) | |
1961 | { | |
1962 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1963 | ||
1964 | return sprintf(buf, "%d\n", st->fail); | |
1965 | } | |
1966 | ||
1967 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
1968 | ||
98f8cdce TG |
1969 | static struct attribute *cpuhp_cpu_attrs[] = { |
1970 | &dev_attr_state.attr, | |
1971 | &dev_attr_target.attr, | |
1db49484 | 1972 | &dev_attr_fail.attr, |
98f8cdce TG |
1973 | NULL |
1974 | }; | |
1975 | ||
993647a2 | 1976 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
1977 | .attrs = cpuhp_cpu_attrs, |
1978 | .name = "hotplug", | |
1979 | NULL | |
1980 | }; | |
1981 | ||
1982 | static ssize_t show_cpuhp_states(struct device *dev, | |
1983 | struct device_attribute *attr, char *buf) | |
1984 | { | |
1985 | ssize_t cur, res = 0; | |
1986 | int i; | |
1987 | ||
1988 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 1989 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
1990 | struct cpuhp_step *sp = cpuhp_get_step(i); |
1991 | ||
1992 | if (sp->name) { | |
1993 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
1994 | buf += cur; | |
1995 | res += cur; | |
1996 | } | |
1997 | } | |
1998 | mutex_unlock(&cpuhp_state_mutex); | |
1999 | return res; | |
2000 | } | |
2001 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2002 | ||
2003 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2004 | &dev_attr_states.attr, | |
2005 | NULL | |
2006 | }; | |
2007 | ||
993647a2 | 2008 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2009 | .attrs = cpuhp_cpu_root_attrs, |
2010 | .name = "hotplug", | |
2011 | NULL | |
2012 | }; | |
2013 | ||
47b4c679 TG |
2014 | #ifdef CONFIG_HOTPLUG_SMT |
2015 | ||
2016 | static const char *smt_states[] = { | |
2017 | [CPU_SMT_ENABLED] = "on", | |
2018 | [CPU_SMT_DISABLED] = "off", | |
2019 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2020 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2021 | }; | |
2022 | ||
2023 | static ssize_t | |
2024 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2025 | { | |
2026 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); | |
2027 | } | |
2028 | ||
2029 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2030 | { | |
2031 | struct device *dev = get_cpu_device(cpu); | |
2032 | ||
2033 | dev->offline = true; | |
2034 | /* Tell user space about the state change */ | |
2035 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2036 | } | |
2037 | ||
b582c9f2 TG |
2038 | static void cpuhp_online_cpu_device(unsigned int cpu) |
2039 | { | |
2040 | struct device *dev = get_cpu_device(cpu); | |
2041 | ||
2042 | dev->offline = false; | |
2043 | /* Tell user space about the state change */ | |
2044 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2045 | } | |
2046 | ||
47b4c679 TG |
2047 | static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) |
2048 | { | |
2049 | int cpu, ret = 0; | |
2050 | ||
2051 | cpu_maps_update_begin(); | |
2052 | for_each_online_cpu(cpu) { | |
2053 | if (topology_is_primary_thread(cpu)) | |
2054 | continue; | |
2055 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2056 | if (ret) | |
2057 | break; | |
2058 | /* | |
2059 | * As this needs to hold the cpu maps lock it's impossible | |
2060 | * to call device_offline() because that ends up calling | |
2061 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2062 | * needs to be held as this might race against in kernel | |
2063 | * abusers of the hotplug machinery (thermal management). | |
2064 | * | |
2065 | * So nothing would update device:offline state. That would | |
2066 | * leave the sysfs entry stale and prevent onlining after | |
2067 | * smt control has been changed to 'off' again. This is | |
2068 | * called under the sysfs hotplug lock, so it is properly | |
2069 | * serialized against the regular offline usage. | |
2070 | */ | |
2071 | cpuhp_offline_cpu_device(cpu); | |
2072 | } | |
2073 | if (!ret) | |
2074 | cpu_smt_control = ctrlval; | |
2075 | cpu_maps_update_done(); | |
2076 | return ret; | |
2077 | } | |
2078 | ||
b582c9f2 | 2079 | static int cpuhp_smt_enable(void) |
47b4c679 | 2080 | { |
b582c9f2 TG |
2081 | int cpu, ret = 0; |
2082 | ||
47b4c679 TG |
2083 | cpu_maps_update_begin(); |
2084 | cpu_smt_control = CPU_SMT_ENABLED; | |
b582c9f2 TG |
2085 | for_each_present_cpu(cpu) { |
2086 | /* Skip online CPUs and CPUs on offline nodes */ | |
2087 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2088 | continue; | |
2089 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2090 | if (ret) | |
2091 | break; | |
2092 | /* See comment in cpuhp_smt_disable() */ | |
2093 | cpuhp_online_cpu_device(cpu); | |
2094 | } | |
47b4c679 | 2095 | cpu_maps_update_done(); |
b582c9f2 | 2096 | return ret; |
47b4c679 TG |
2097 | } |
2098 | ||
2099 | static ssize_t | |
2100 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2101 | const char *buf, size_t count) | |
2102 | { | |
2103 | int ctrlval, ret; | |
2104 | ||
2105 | if (sysfs_streq(buf, "on")) | |
2106 | ctrlval = CPU_SMT_ENABLED; | |
2107 | else if (sysfs_streq(buf, "off")) | |
2108 | ctrlval = CPU_SMT_DISABLED; | |
2109 | else if (sysfs_streq(buf, "forceoff")) | |
2110 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2111 | else | |
2112 | return -EINVAL; | |
2113 | ||
2114 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2115 | return -EPERM; | |
2116 | ||
2117 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2118 | return -ENODEV; | |
2119 | ||
2120 | ret = lock_device_hotplug_sysfs(); | |
2121 | if (ret) | |
2122 | return ret; | |
2123 | ||
2124 | if (ctrlval != cpu_smt_control) { | |
2125 | switch (ctrlval) { | |
2126 | case CPU_SMT_ENABLED: | |
b582c9f2 | 2127 | ret = cpuhp_smt_enable(); |
47b4c679 TG |
2128 | break; |
2129 | case CPU_SMT_DISABLED: | |
2130 | case CPU_SMT_FORCE_DISABLED: | |
2131 | ret = cpuhp_smt_disable(ctrlval); | |
2132 | break; | |
2133 | } | |
2134 | } | |
2135 | ||
2136 | unlock_device_hotplug(); | |
2137 | return ret ? ret : count; | |
2138 | } | |
2139 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); | |
2140 | ||
2141 | static ssize_t | |
2142 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2143 | { | |
2144 | bool active = topology_max_smt_threads() > 1; | |
2145 | ||
2146 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); | |
2147 | } | |
2148 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2149 | ||
2150 | static struct attribute *cpuhp_smt_attrs[] = { | |
2151 | &dev_attr_control.attr, | |
2152 | &dev_attr_active.attr, | |
2153 | NULL | |
2154 | }; | |
2155 | ||
2156 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2157 | .attrs = cpuhp_smt_attrs, | |
2158 | .name = "smt", | |
2159 | NULL | |
2160 | }; | |
2161 | ||
2162 | static int __init cpu_smt_state_init(void) | |
2163 | { | |
47b4c679 TG |
2164 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2165 | &cpuhp_smt_attr_group); | |
2166 | } | |
2167 | ||
2168 | #else | |
2169 | static inline int cpu_smt_state_init(void) { return 0; } | |
2170 | #endif | |
2171 | ||
98f8cdce TG |
2172 | static int __init cpuhp_sysfs_init(void) |
2173 | { | |
2174 | int cpu, ret; | |
2175 | ||
47b4c679 TG |
2176 | ret = cpu_smt_state_init(); |
2177 | if (ret) | |
2178 | return ret; | |
2179 | ||
98f8cdce TG |
2180 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2181 | &cpuhp_cpu_root_attr_group); | |
2182 | if (ret) | |
2183 | return ret; | |
2184 | ||
2185 | for_each_possible_cpu(cpu) { | |
2186 | struct device *dev = get_cpu_device(cpu); | |
2187 | ||
2188 | if (!dev) | |
2189 | continue; | |
2190 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2191 | if (ret) | |
2192 | return ret; | |
2193 | } | |
2194 | return 0; | |
2195 | } | |
2196 | device_initcall(cpuhp_sysfs_init); | |
2197 | #endif | |
2198 | ||
e56b3bc7 LT |
2199 | /* |
2200 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2201 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2202 | * | |
e0b582ec | 2203 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2204 | * mask value that has a single bit set only. |
2205 | */ | |
b8d317d1 | 2206 | |
e56b3bc7 | 2207 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2208 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2209 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2210 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2211 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2212 | |
e56b3bc7 LT |
2213 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2214 | ||
2215 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2216 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2217 | #if BITS_PER_LONG > 32 | |
2218 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2219 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2220 | #endif |
2221 | }; | |
e56b3bc7 | 2222 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2223 | |
2224 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2225 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2226 | |
2227 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2228 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2229 | = {CPU_BITS_ALL}; |
b3199c02 | 2230 | #else |
4b804c85 | 2231 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2232 | #endif |
4b804c85 | 2233 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2234 | |
4b804c85 RV |
2235 | struct cpumask __cpu_online_mask __read_mostly; |
2236 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2237 | |
4b804c85 RV |
2238 | struct cpumask __cpu_present_mask __read_mostly; |
2239 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2240 | |
4b804c85 RV |
2241 | struct cpumask __cpu_active_mask __read_mostly; |
2242 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2243 | |
3fa41520 RR |
2244 | void init_cpu_present(const struct cpumask *src) |
2245 | { | |
c4c54dd1 | 2246 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2247 | } |
2248 | ||
2249 | void init_cpu_possible(const struct cpumask *src) | |
2250 | { | |
c4c54dd1 | 2251 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2252 | } |
2253 | ||
2254 | void init_cpu_online(const struct cpumask *src) | |
2255 | { | |
c4c54dd1 | 2256 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2257 | } |
cff7d378 TG |
2258 | |
2259 | /* | |
2260 | * Activate the first processor. | |
2261 | */ | |
2262 | void __init boot_cpu_init(void) | |
2263 | { | |
2264 | int cpu = smp_processor_id(); | |
2265 | ||
2266 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2267 | set_cpu_online(cpu, true); | |
2268 | set_cpu_active(cpu, true); | |
2269 | set_cpu_present(cpu, true); | |
2270 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2271 | |
2272 | #ifdef CONFIG_SMP | |
2273 | __boot_cpu_id = cpu; | |
2274 | #endif | |
cff7d378 TG |
2275 | } |
2276 | ||
2277 | /* | |
2278 | * Must be called _AFTER_ setting up the per_cpu areas | |
2279 | */ | |
2280 | void __init boot_cpu_state_init(void) | |
2281 | { | |
c1f7608e TH |
2282 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->booted_once = true; |
2283 | per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE; | |
cff7d378 | 2284 | } |