Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* CPU control. |
2 | * (C) 2001, 2002, 2003, 2004 Rusty Russell | |
3 | * | |
4 | * This code is licenced under the GPL. | |
5 | */ | |
6 | #include <linux/proc_fs.h> | |
7 | #include <linux/smp.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/notifier.h> | |
3f07c014 | 10 | #include <linux/sched/signal.h> |
ef8bd77f | 11 | #include <linux/sched/hotplug.h> |
29930025 | 12 | #include <linux/sched/task.h> |
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; | |
0cc3cd21 | 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); |
17a2f1ce | 128 | static struct cpuhp_step cpuhp_hp_states[]; |
cff7d378 | 129 | |
a724632c TG |
130 | static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
131 | { | |
17a2f1ce | 132 | return cpuhp_hp_states + state; |
a724632c TG |
133 | } |
134 | ||
cff7d378 TG |
135 | /** |
136 | * cpuhp_invoke_callback _ Invoke the callbacks for a given state | |
137 | * @cpu: The cpu for which the callback should be invoked | |
96abb968 | 138 | * @state: The state to do callbacks for |
a724632c | 139 | * @bringup: True if the bringup callback should be invoked |
96abb968 PZ |
140 | * @node: For multi-instance, do a single entry callback for install/remove |
141 | * @lastp: For multi-instance rollback, remember how far we got | |
cff7d378 | 142 | * |
cf392d10 | 143 | * Called from cpu hotplug and from the state register machinery. |
cff7d378 | 144 | */ |
a724632c | 145 | static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
96abb968 PZ |
146 | bool bringup, struct hlist_node *node, |
147 | struct hlist_node **lastp) | |
cff7d378 TG |
148 | { |
149 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
a724632c | 150 | struct cpuhp_step *step = cpuhp_get_step(state); |
cf392d10 TG |
151 | int (*cbm)(unsigned int cpu, struct hlist_node *node); |
152 | int (*cb)(unsigned int cpu); | |
153 | int ret, cnt; | |
154 | ||
1db49484 PZ |
155 | if (st->fail == state) { |
156 | st->fail = CPUHP_INVALID; | |
157 | ||
158 | if (!(bringup ? step->startup.single : step->teardown.single)) | |
159 | return 0; | |
160 | ||
161 | return -EAGAIN; | |
162 | } | |
163 | ||
cf392d10 | 164 | if (!step->multi_instance) { |
96abb968 | 165 | WARN_ON_ONCE(lastp && *lastp); |
3c1627e9 | 166 | cb = bringup ? step->startup.single : step->teardown.single; |
cf392d10 TG |
167 | if (!cb) |
168 | return 0; | |
a724632c | 169 | trace_cpuhp_enter(cpu, st->target, state, cb); |
cff7d378 | 170 | ret = cb(cpu); |
a724632c | 171 | trace_cpuhp_exit(cpu, st->state, state, ret); |
cf392d10 TG |
172 | return ret; |
173 | } | |
3c1627e9 | 174 | cbm = bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
175 | if (!cbm) |
176 | return 0; | |
177 | ||
178 | /* Single invocation for instance add/remove */ | |
179 | if (node) { | |
96abb968 | 180 | WARN_ON_ONCE(lastp && *lastp); |
cf392d10 TG |
181 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
182 | ret = cbm(cpu, node); | |
183 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
184 | return ret; | |
185 | } | |
186 | ||
187 | /* State transition. Invoke on all instances */ | |
188 | cnt = 0; | |
189 | hlist_for_each(node, &step->list) { | |
96abb968 PZ |
190 | if (lastp && node == *lastp) |
191 | break; | |
192 | ||
cf392d10 TG |
193 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
194 | ret = cbm(cpu, node); | |
195 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
96abb968 PZ |
196 | if (ret) { |
197 | if (!lastp) | |
198 | goto err; | |
199 | ||
200 | *lastp = node; | |
201 | return ret; | |
202 | } | |
cf392d10 TG |
203 | cnt++; |
204 | } | |
96abb968 PZ |
205 | if (lastp) |
206 | *lastp = NULL; | |
cf392d10 TG |
207 | return 0; |
208 | err: | |
209 | /* Rollback the instances if one failed */ | |
3c1627e9 | 210 | cbm = !bringup ? step->startup.multi : step->teardown.multi; |
cf392d10 TG |
211 | if (!cbm) |
212 | return ret; | |
213 | ||
214 | hlist_for_each(node, &step->list) { | |
215 | if (!cnt--) | |
216 | break; | |
724a8688 PZ |
217 | |
218 | trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); | |
219 | ret = cbm(cpu, node); | |
220 | trace_cpuhp_exit(cpu, st->state, state, ret); | |
221 | /* | |
222 | * Rollback must not fail, | |
223 | */ | |
224 | WARN_ON_ONCE(ret); | |
cff7d378 TG |
225 | } |
226 | return ret; | |
227 | } | |
228 | ||
98a79d6a | 229 | #ifdef CONFIG_SMP |
fcb3029a AB |
230 | static bool cpuhp_is_ap_state(enum cpuhp_state state) |
231 | { | |
232 | /* | |
233 | * The extra check for CPUHP_TEARDOWN_CPU is only for documentation | |
234 | * purposes as that state is handled explicitly in cpu_down. | |
235 | */ | |
236 | return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; | |
237 | } | |
238 | ||
5ebe7742 PZ |
239 | static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
240 | { | |
241 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
242 | wait_for_completion(done); | |
243 | } | |
244 | ||
245 | static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) | |
246 | { | |
247 | struct completion *done = bringup ? &st->done_up : &st->done_down; | |
248 | complete(done); | |
249 | } | |
250 | ||
251 | /* | |
252 | * The former STARTING/DYING states, ran with IRQs disabled and must not fail. | |
253 | */ | |
254 | static bool cpuhp_is_atomic_state(enum cpuhp_state state) | |
255 | { | |
256 | return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; | |
257 | } | |
258 | ||
b3199c02 | 259 | /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
aa953877 | 260 | static DEFINE_MUTEX(cpu_add_remove_lock); |
090e77c3 TG |
261 | bool cpuhp_tasks_frozen; |
262 | EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); | |
1da177e4 | 263 | |
79a6cdeb | 264 | /* |
93ae4f97 SB |
265 | * The following two APIs (cpu_maps_update_begin/done) must be used when |
266 | * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. | |
79a6cdeb LJ |
267 | */ |
268 | void cpu_maps_update_begin(void) | |
269 | { | |
270 | mutex_lock(&cpu_add_remove_lock); | |
271 | } | |
272 | ||
273 | void cpu_maps_update_done(void) | |
274 | { | |
275 | mutex_unlock(&cpu_add_remove_lock); | |
276 | } | |
1da177e4 | 277 | |
fc8dffd3 TG |
278 | /* |
279 | * If set, cpu_up and cpu_down will return -EBUSY and do nothing. | |
e3920fb4 RW |
280 | * Should always be manipulated under cpu_add_remove_lock |
281 | */ | |
282 | static int cpu_hotplug_disabled; | |
283 | ||
79a6cdeb LJ |
284 | #ifdef CONFIG_HOTPLUG_CPU |
285 | ||
fc8dffd3 | 286 | DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
a19423b9 | 287 | |
8f553c49 | 288 | void cpus_read_lock(void) |
a9d9baa1 | 289 | { |
fc8dffd3 | 290 | percpu_down_read(&cpu_hotplug_lock); |
a9d9baa1 | 291 | } |
8f553c49 | 292 | EXPORT_SYMBOL_GPL(cpus_read_lock); |
90d45d17 | 293 | |
6f4ceee9 WL |
294 | int cpus_read_trylock(void) |
295 | { | |
296 | return percpu_down_read_trylock(&cpu_hotplug_lock); | |
297 | } | |
298 | EXPORT_SYMBOL_GPL(cpus_read_trylock); | |
299 | ||
8f553c49 | 300 | void cpus_read_unlock(void) |
a9d9baa1 | 301 | { |
fc8dffd3 | 302 | percpu_up_read(&cpu_hotplug_lock); |
a9d9baa1 | 303 | } |
8f553c49 | 304 | EXPORT_SYMBOL_GPL(cpus_read_unlock); |
a9d9baa1 | 305 | |
8f553c49 | 306 | void cpus_write_lock(void) |
d221938c | 307 | { |
fc8dffd3 | 308 | percpu_down_write(&cpu_hotplug_lock); |
d221938c | 309 | } |
87af9e7f | 310 | |
8f553c49 | 311 | void cpus_write_unlock(void) |
d221938c | 312 | { |
fc8dffd3 | 313 | percpu_up_write(&cpu_hotplug_lock); |
d221938c GS |
314 | } |
315 | ||
fc8dffd3 | 316 | void lockdep_assert_cpus_held(void) |
d221938c | 317 | { |
fc8dffd3 | 318 | percpu_rwsem_assert_held(&cpu_hotplug_lock); |
d221938c | 319 | } |
79a6cdeb | 320 | |
16e53dbf SB |
321 | /* |
322 | * Wait for currently running CPU hotplug operations to complete (if any) and | |
323 | * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects | |
324 | * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the | |
325 | * hotplug path before performing hotplug operations. So acquiring that lock | |
326 | * guarantees mutual exclusion from any currently running hotplug operations. | |
327 | */ | |
328 | void cpu_hotplug_disable(void) | |
329 | { | |
330 | cpu_maps_update_begin(); | |
89af7ba5 | 331 | cpu_hotplug_disabled++; |
16e53dbf SB |
332 | cpu_maps_update_done(); |
333 | } | |
32145c46 | 334 | EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
16e53dbf | 335 | |
01b41159 LW |
336 | static void __cpu_hotplug_enable(void) |
337 | { | |
338 | if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) | |
339 | return; | |
340 | cpu_hotplug_disabled--; | |
341 | } | |
342 | ||
16e53dbf SB |
343 | void cpu_hotplug_enable(void) |
344 | { | |
345 | cpu_maps_update_begin(); | |
01b41159 | 346 | __cpu_hotplug_enable(); |
16e53dbf SB |
347 | cpu_maps_update_done(); |
348 | } | |
32145c46 | 349 | EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
b9d10be7 | 350 | #endif /* CONFIG_HOTPLUG_CPU */ |
79a6cdeb | 351 | |
0cc3cd21 TG |
352 | #ifdef CONFIG_HOTPLUG_SMT |
353 | enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; | |
26acfb66 | 354 | EXPORT_SYMBOL_GPL(cpu_smt_control); |
0cc3cd21 | 355 | |
bc2d8d26 TG |
356 | static bool cpu_smt_available __read_mostly; |
357 | ||
8e1b706b | 358 | void __init cpu_smt_disable(bool force) |
0cc3cd21 | 359 | { |
8e1b706b JK |
360 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || |
361 | cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
362 | return; | |
363 | ||
364 | if (force) { | |
0cc3cd21 TG |
365 | pr_info("SMT: Force disabled\n"); |
366 | cpu_smt_control = CPU_SMT_FORCE_DISABLED; | |
8e1b706b JK |
367 | } else { |
368 | cpu_smt_control = CPU_SMT_DISABLED; | |
0cc3cd21 | 369 | } |
8e1b706b JK |
370 | } |
371 | ||
fee0aede TG |
372 | /* |
373 | * The decision whether SMT is supported can only be done after the full | |
bc2d8d26 TG |
374 | * CPU identification. Called from architecture code before non boot CPUs |
375 | * are brought up. | |
fee0aede | 376 | */ |
bc2d8d26 | 377 | void __init cpu_smt_check_topology_early(void) |
fee0aede TG |
378 | { |
379 | if (!topology_smt_supported()) | |
380 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; | |
381 | } | |
382 | ||
bc2d8d26 TG |
383 | /* |
384 | * If SMT was disabled by BIOS, detect it here, after the CPUs have been | |
385 | * brought online. This ensures the smt/l1tf sysfs entries are consistent | |
386 | * with reality. cpu_smt_available is set to true during the bringup of non | |
387 | * boot CPUs when a SMT sibling is detected. Note, this may overwrite | |
388 | * cpu_smt_control's previous setting. | |
389 | */ | |
390 | void __init cpu_smt_check_topology(void) | |
391 | { | |
392 | if (!cpu_smt_available) | |
393 | cpu_smt_control = CPU_SMT_NOT_SUPPORTED; | |
394 | } | |
395 | ||
8e1b706b JK |
396 | static int __init smt_cmdline_disable(char *str) |
397 | { | |
398 | cpu_smt_disable(str && !strcmp(str, "force")); | |
0cc3cd21 TG |
399 | return 0; |
400 | } | |
401 | early_param("nosmt", smt_cmdline_disable); | |
402 | ||
403 | static inline bool cpu_smt_allowed(unsigned int cpu) | |
404 | { | |
bc2d8d26 | 405 | if (topology_is_primary_thread(cpu)) |
0cc3cd21 TG |
406 | return true; |
407 | ||
bc2d8d26 TG |
408 | /* |
409 | * If the CPU is not a 'primary' thread and the booted_once bit is | |
410 | * set then the processor has SMT support. Store this information | |
411 | * for the late check of SMT support in cpu_smt_check_topology(). | |
412 | */ | |
413 | if (per_cpu(cpuhp_state, cpu).booted_once) | |
414 | cpu_smt_available = true; | |
415 | ||
416 | if (cpu_smt_control == CPU_SMT_ENABLED) | |
0cc3cd21 TG |
417 | return true; |
418 | ||
419 | /* | |
420 | * On x86 it's required to boot all logical CPUs at least once so | |
421 | * that the init code can get a chance to set CR4.MCE on each | |
422 | * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any | |
423 | * core will shutdown the machine. | |
424 | */ | |
425 | return !per_cpu(cpuhp_state, cpu).booted_once; | |
426 | } | |
427 | #else | |
428 | static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } | |
429 | #endif | |
430 | ||
4dddfb5f PZ |
431 | static inline enum cpuhp_state |
432 | cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
433 | { | |
434 | enum cpuhp_state prev_state = st->state; | |
435 | ||
436 | st->rollback = false; | |
437 | st->last = NULL; | |
438 | ||
439 | st->target = target; | |
440 | st->single = false; | |
441 | st->bringup = st->state < target; | |
442 | ||
443 | return prev_state; | |
444 | } | |
445 | ||
446 | static inline void | |
447 | cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) | |
448 | { | |
449 | st->rollback = true; | |
450 | ||
451 | /* | |
452 | * If we have st->last we need to undo partial multi_instance of this | |
453 | * state first. Otherwise start undo at the previous state. | |
454 | */ | |
455 | if (!st->last) { | |
456 | if (st->bringup) | |
457 | st->state--; | |
458 | else | |
459 | st->state++; | |
460 | } | |
461 | ||
462 | st->target = prev_state; | |
463 | st->bringup = !st->bringup; | |
464 | } | |
465 | ||
466 | /* Regular hotplug invocation of the AP hotplug thread */ | |
467 | static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) | |
468 | { | |
469 | if (!st->single && st->state == st->target) | |
470 | return; | |
471 | ||
472 | st->result = 0; | |
473 | /* | |
474 | * Make sure the above stores are visible before should_run becomes | |
475 | * true. Paired with the mb() above in cpuhp_thread_fun() | |
476 | */ | |
477 | smp_mb(); | |
478 | st->should_run = true; | |
479 | wake_up_process(st->thread); | |
5ebe7742 | 480 | wait_for_ap_thread(st, st->bringup); |
4dddfb5f PZ |
481 | } |
482 | ||
483 | static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) | |
484 | { | |
485 | enum cpuhp_state prev_state; | |
486 | int ret; | |
487 | ||
488 | prev_state = cpuhp_set_state(st, target); | |
489 | __cpuhp_kick_ap(st); | |
490 | if ((ret = st->result)) { | |
491 | cpuhp_reset_state(st, prev_state); | |
492 | __cpuhp_kick_ap(st); | |
493 | } | |
494 | ||
495 | return ret; | |
496 | } | |
9cd4f1a4 | 497 | |
8df3e07e TG |
498 | static int bringup_wait_for_ap(unsigned int cpu) |
499 | { | |
500 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
501 | ||
9cd4f1a4 | 502 | /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
5ebe7742 | 503 | wait_for_ap_thread(st, true); |
dea1d0f5 TG |
504 | if (WARN_ON_ONCE((!cpu_online(cpu)))) |
505 | return -ECANCELED; | |
9cd4f1a4 TG |
506 | |
507 | /* Unpark the stopper thread and the hotplug thread of the target cpu */ | |
508 | stop_machine_unpark(cpu); | |
509 | kthread_unpark(st->thread); | |
510 | ||
0cc3cd21 TG |
511 | /* |
512 | * SMT soft disabling on X86 requires to bring the CPU out of the | |
513 | * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The | |
514 | * CPU marked itself as booted_once in cpu_notify_starting() so the | |
515 | * cpu_smt_allowed() check will now return false if this is not the | |
516 | * primary sibling. | |
517 | */ | |
518 | if (!cpu_smt_allowed(cpu)) | |
519 | return -ECANCELED; | |
520 | ||
4dddfb5f PZ |
521 | if (st->target <= CPUHP_AP_ONLINE_IDLE) |
522 | return 0; | |
523 | ||
524 | return cpuhp_kick_ap(st, st->target); | |
8df3e07e TG |
525 | } |
526 | ||
ba997462 TG |
527 | static int bringup_cpu(unsigned int cpu) |
528 | { | |
529 | struct task_struct *idle = idle_thread_get(cpu); | |
530 | int ret; | |
531 | ||
aa877175 BO |
532 | /* |
533 | * Some architectures have to walk the irq descriptors to | |
534 | * setup the vector space for the cpu which comes online. | |
535 | * Prevent irq alloc/free across the bringup. | |
536 | */ | |
537 | irq_lock_sparse(); | |
538 | ||
ba997462 TG |
539 | /* Arch-specific enabling code. */ |
540 | ret = __cpu_up(cpu, idle); | |
aa877175 | 541 | irq_unlock_sparse(); |
530e9b76 | 542 | if (ret) |
ba997462 | 543 | return ret; |
9cd4f1a4 | 544 | return bringup_wait_for_ap(cpu); |
ba997462 TG |
545 | } |
546 | ||
2e1a3483 TG |
547 | /* |
548 | * Hotplug state machine related functions | |
549 | */ | |
2e1a3483 | 550 | |
a724632c | 551 | static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
2e1a3483 TG |
552 | { |
553 | for (st->state--; st->state > st->target; st->state--) { | |
a724632c | 554 | struct cpuhp_step *step = cpuhp_get_step(st->state); |
2e1a3483 TG |
555 | |
556 | if (!step->skip_onerr) | |
96abb968 | 557 | cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); |
2e1a3483 TG |
558 | } |
559 | } | |
560 | ||
561 | static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
a724632c | 562 | enum cpuhp_state target) |
2e1a3483 TG |
563 | { |
564 | enum cpuhp_state prev_state = st->state; | |
565 | int ret = 0; | |
566 | ||
567 | while (st->state < target) { | |
2e1a3483 | 568 | st->state++; |
96abb968 | 569 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
2e1a3483 TG |
570 | if (ret) { |
571 | st->target = prev_state; | |
a724632c | 572 | undo_cpu_up(cpu, st); |
2e1a3483 TG |
573 | break; |
574 | } | |
575 | } | |
576 | return ret; | |
577 | } | |
578 | ||
4cb28ced TG |
579 | /* |
580 | * The cpu hotplug threads manage the bringup and teardown of the cpus | |
581 | */ | |
582 | static void cpuhp_create(unsigned int cpu) | |
583 | { | |
584 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
585 | ||
5ebe7742 PZ |
586 | init_completion(&st->done_up); |
587 | init_completion(&st->done_down); | |
4cb28ced TG |
588 | } |
589 | ||
590 | static int cpuhp_should_run(unsigned int cpu) | |
591 | { | |
592 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
593 | ||
594 | return st->should_run; | |
595 | } | |
596 | ||
4cb28ced TG |
597 | /* |
598 | * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke | |
599 | * callbacks when a state gets [un]installed at runtime. | |
4dddfb5f PZ |
600 | * |
601 | * Each invocation of this function by the smpboot thread does a single AP | |
602 | * state callback. | |
603 | * | |
604 | * It has 3 modes of operation: | |
605 | * - single: runs st->cb_state | |
606 | * - up: runs ++st->state, while st->state < st->target | |
607 | * - down: runs st->state--, while st->state > st->target | |
608 | * | |
609 | * When complete or on error, should_run is cleared and the completion is fired. | |
4cb28ced TG |
610 | */ |
611 | static void cpuhp_thread_fun(unsigned int cpu) | |
612 | { | |
613 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
4dddfb5f PZ |
614 | bool bringup = st->bringup; |
615 | enum cpuhp_state state; | |
4cb28ced TG |
616 | |
617 | /* | |
4dddfb5f PZ |
618 | * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
619 | * that if we see ->should_run we also see the rest of the state. | |
4cb28ced TG |
620 | */ |
621 | smp_mb(); | |
4cb28ced | 622 | |
4dddfb5f PZ |
623 | if (WARN_ON_ONCE(!st->should_run)) |
624 | return; | |
4cb28ced | 625 | |
5f4b55e1 | 626 | cpuhp_lock_acquire(bringup); |
4dddfb5f | 627 | |
a724632c | 628 | if (st->single) { |
4dddfb5f PZ |
629 | state = st->cb_state; |
630 | st->should_run = false; | |
631 | } else { | |
632 | if (bringup) { | |
633 | st->state++; | |
634 | state = st->state; | |
635 | st->should_run = (st->state < st->target); | |
636 | WARN_ON_ONCE(st->state > st->target); | |
4cb28ced | 637 | } else { |
4dddfb5f PZ |
638 | state = st->state; |
639 | st->state--; | |
640 | st->should_run = (st->state > st->target); | |
641 | WARN_ON_ONCE(st->state < st->target); | |
4cb28ced | 642 | } |
4dddfb5f PZ |
643 | } |
644 | ||
645 | WARN_ON_ONCE(!cpuhp_is_ap_state(state)); | |
646 | ||
647 | if (st->rollback) { | |
648 | struct cpuhp_step *step = cpuhp_get_step(state); | |
649 | if (step->skip_onerr) | |
650 | goto next; | |
651 | } | |
652 | ||
653 | if (cpuhp_is_atomic_state(state)) { | |
654 | local_irq_disable(); | |
655 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); | |
656 | local_irq_enable(); | |
3b9d6da6 | 657 | |
4dddfb5f PZ |
658 | /* |
659 | * STARTING/DYING must not fail! | |
660 | */ | |
661 | WARN_ON_ONCE(st->result); | |
4cb28ced | 662 | } else { |
4dddfb5f PZ |
663 | st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
664 | } | |
665 | ||
666 | if (st->result) { | |
667 | /* | |
668 | * If we fail on a rollback, we're up a creek without no | |
669 | * paddle, no way forward, no way back. We loose, thanks for | |
670 | * playing. | |
671 | */ | |
672 | WARN_ON_ONCE(st->rollback); | |
673 | st->should_run = false; | |
4cb28ced | 674 | } |
4dddfb5f PZ |
675 | |
676 | next: | |
5f4b55e1 | 677 | cpuhp_lock_release(bringup); |
4dddfb5f PZ |
678 | |
679 | if (!st->should_run) | |
5ebe7742 | 680 | complete_ap_thread(st, bringup); |
4cb28ced TG |
681 | } |
682 | ||
683 | /* Invoke a single callback on a remote cpu */ | |
a724632c | 684 | static int |
cf392d10 TG |
685 | cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
686 | struct hlist_node *node) | |
4cb28ced TG |
687 | { |
688 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f | 689 | int ret; |
4cb28ced TG |
690 | |
691 | if (!cpu_online(cpu)) | |
692 | return 0; | |
693 | ||
5f4b55e1 PZ |
694 | cpuhp_lock_acquire(false); |
695 | cpuhp_lock_release(false); | |
696 | ||
697 | cpuhp_lock_acquire(true); | |
698 | cpuhp_lock_release(true); | |
49dfe2a6 | 699 | |
6a4e2451 TG |
700 | /* |
701 | * If we are up and running, use the hotplug thread. For early calls | |
702 | * we invoke the thread function directly. | |
703 | */ | |
704 | if (!st->thread) | |
96abb968 | 705 | return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
6a4e2451 | 706 | |
4dddfb5f PZ |
707 | st->rollback = false; |
708 | st->last = NULL; | |
709 | ||
710 | st->node = node; | |
711 | st->bringup = bringup; | |
4cb28ced | 712 | st->cb_state = state; |
a724632c | 713 | st->single = true; |
a724632c | 714 | |
4dddfb5f | 715 | __cpuhp_kick_ap(st); |
4cb28ced | 716 | |
4cb28ced | 717 | /* |
4dddfb5f | 718 | * If we failed and did a partial, do a rollback. |
4cb28ced | 719 | */ |
4dddfb5f PZ |
720 | if ((ret = st->result) && st->last) { |
721 | st->rollback = true; | |
722 | st->bringup = !bringup; | |
723 | ||
724 | __cpuhp_kick_ap(st); | |
725 | } | |
726 | ||
1f7c70d6 TG |
727 | /* |
728 | * Clean up the leftovers so the next hotplug operation wont use stale | |
729 | * data. | |
730 | */ | |
731 | st->node = st->last = NULL; | |
4dddfb5f | 732 | return ret; |
1cf4f629 TG |
733 | } |
734 | ||
735 | static int cpuhp_kick_ap_work(unsigned int cpu) | |
736 | { | |
737 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
4dddfb5f PZ |
738 | enum cpuhp_state prev_state = st->state; |
739 | int ret; | |
1cf4f629 | 740 | |
5f4b55e1 PZ |
741 | cpuhp_lock_acquire(false); |
742 | cpuhp_lock_release(false); | |
743 | ||
744 | cpuhp_lock_acquire(true); | |
745 | cpuhp_lock_release(true); | |
4dddfb5f PZ |
746 | |
747 | trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); | |
748 | ret = cpuhp_kick_ap(st, st->target); | |
749 | trace_cpuhp_exit(cpu, st->state, prev_state, ret); | |
750 | ||
751 | return ret; | |
4cb28ced TG |
752 | } |
753 | ||
754 | static struct smp_hotplug_thread cpuhp_threads = { | |
755 | .store = &cpuhp_state.thread, | |
756 | .create = &cpuhp_create, | |
757 | .thread_should_run = cpuhp_should_run, | |
758 | .thread_fn = cpuhp_thread_fun, | |
759 | .thread_comm = "cpuhp/%u", | |
760 | .selfparking = true, | |
761 | }; | |
762 | ||
763 | void __init cpuhp_threads_init(void) | |
764 | { | |
765 | BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); | |
766 | kthread_unpark(this_cpu_read(cpuhp_state.thread)); | |
767 | } | |
768 | ||
777c6e0d | 769 | #ifdef CONFIG_HOTPLUG_CPU |
e4cc2f87 AV |
770 | /** |
771 | * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU | |
772 | * @cpu: a CPU id | |
773 | * | |
774 | * This function walks all processes, finds a valid mm struct for each one and | |
775 | * then clears a corresponding bit in mm's cpumask. While this all sounds | |
776 | * trivial, there are various non-obvious corner cases, which this function | |
777 | * tries to solve in a safe manner. | |
778 | * | |
779 | * Also note that the function uses a somewhat relaxed locking scheme, so it may | |
780 | * be called only for an already offlined CPU. | |
781 | */ | |
cb79295e AV |
782 | void clear_tasks_mm_cpumask(int cpu) |
783 | { | |
784 | struct task_struct *p; | |
785 | ||
786 | /* | |
787 | * This function is called after the cpu is taken down and marked | |
788 | * offline, so its not like new tasks will ever get this cpu set in | |
789 | * their mm mask. -- Peter Zijlstra | |
790 | * Thus, we may use rcu_read_lock() here, instead of grabbing | |
791 | * full-fledged tasklist_lock. | |
792 | */ | |
e4cc2f87 | 793 | WARN_ON(cpu_online(cpu)); |
cb79295e AV |
794 | rcu_read_lock(); |
795 | for_each_process(p) { | |
796 | struct task_struct *t; | |
797 | ||
e4cc2f87 AV |
798 | /* |
799 | * Main thread might exit, but other threads may still have | |
800 | * a valid mm. Find one. | |
801 | */ | |
cb79295e AV |
802 | t = find_lock_task_mm(p); |
803 | if (!t) | |
804 | continue; | |
805 | cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); | |
806 | task_unlock(t); | |
807 | } | |
808 | rcu_read_unlock(); | |
809 | } | |
810 | ||
1da177e4 | 811 | /* Take this CPU down. */ |
71cf5aee | 812 | static int take_cpu_down(void *_param) |
1da177e4 | 813 | { |
4baa0afc TG |
814 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
815 | enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); | |
090e77c3 | 816 | int err, cpu = smp_processor_id(); |
724a8688 | 817 | int ret; |
1da177e4 | 818 | |
1da177e4 LT |
819 | /* Ensure this CPU doesn't handle any more interrupts. */ |
820 | err = __cpu_disable(); | |
821 | if (err < 0) | |
f3705136 | 822 | return err; |
1da177e4 | 823 | |
a724632c TG |
824 | /* |
825 | * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not | |
826 | * do this step again. | |
827 | */ | |
828 | WARN_ON(st->state != CPUHP_TEARDOWN_CPU); | |
829 | st->state--; | |
4baa0afc | 830 | /* Invoke the former CPU_DYING callbacks */ |
724a8688 PZ |
831 | for (; st->state > target; st->state--) { |
832 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
833 | /* | |
834 | * DYING must not fail! | |
835 | */ | |
836 | WARN_ON_ONCE(ret); | |
837 | } | |
4baa0afc | 838 | |
52c063d1 TG |
839 | /* Give up timekeeping duties */ |
840 | tick_handover_do_timer(); | |
14e568e7 | 841 | /* Park the stopper thread */ |
090e77c3 | 842 | stop_machine_park(cpu); |
f3705136 | 843 | return 0; |
1da177e4 LT |
844 | } |
845 | ||
98458172 | 846 | static int takedown_cpu(unsigned int cpu) |
1da177e4 | 847 | { |
e69aab13 | 848 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
98458172 | 849 | int err; |
1da177e4 | 850 | |
2a58c527 | 851 | /* Park the smpboot threads */ |
1cf4f629 TG |
852 | kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
853 | ||
6acce3ef | 854 | /* |
a8994181 TG |
855 | * Prevent irq alloc/free while the dying cpu reorganizes the |
856 | * interrupt affinities. | |
6acce3ef | 857 | */ |
a8994181 | 858 | irq_lock_sparse(); |
6acce3ef | 859 | |
a8994181 TG |
860 | /* |
861 | * So now all preempt/rcu users must observe !cpu_active(). | |
862 | */ | |
210e2133 | 863 | err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
04321587 | 864 | if (err) { |
3b9d6da6 | 865 | /* CPU refused to die */ |
a8994181 | 866 | irq_unlock_sparse(); |
3b9d6da6 SAS |
867 | /* Unpark the hotplug thread so we can rollback there */ |
868 | kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); | |
98458172 | 869 | return err; |
8fa1d7d3 | 870 | } |
04321587 | 871 | BUG_ON(cpu_online(cpu)); |
1da177e4 | 872 | |
48c5ccae | 873 | /* |
5b1ead68 BJ |
874 | * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed |
875 | * all runnable tasks from the CPU, there's only the idle task left now | |
48c5ccae | 876 | * that the migration thread is done doing the stop_machine thing. |
51a96c77 PZ |
877 | * |
878 | * Wait for the stop thread to go away. | |
48c5ccae | 879 | */ |
5ebe7742 | 880 | wait_for_ap_thread(st, false); |
e69aab13 | 881 | BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
1da177e4 | 882 | |
a8994181 TG |
883 | /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
884 | irq_unlock_sparse(); | |
885 | ||
345527b1 | 886 | hotplug_cpu__broadcast_tick_pull(cpu); |
1da177e4 LT |
887 | /* This actually kills the CPU. */ |
888 | __cpu_die(cpu); | |
889 | ||
a49b116d | 890 | tick_cleanup_dead_cpu(cpu); |
a58163d8 | 891 | rcutree_migrate_callbacks(cpu); |
98458172 TG |
892 | return 0; |
893 | } | |
1da177e4 | 894 | |
71f87b2f TG |
895 | static void cpuhp_complete_idle_dead(void *arg) |
896 | { | |
897 | struct cpuhp_cpu_state *st = arg; | |
898 | ||
5ebe7742 | 899 | complete_ap_thread(st, false); |
71f87b2f TG |
900 | } |
901 | ||
e69aab13 TG |
902 | void cpuhp_report_idle_dead(void) |
903 | { | |
904 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); | |
905 | ||
906 | BUG_ON(st->state != CPUHP_AP_OFFLINE); | |
27d50c7e | 907 | rcu_report_dead(smp_processor_id()); |
71f87b2f TG |
908 | st->state = CPUHP_AP_IDLE_DEAD; |
909 | /* | |
910 | * We cannot call complete after rcu_report_dead() so we delegate it | |
911 | * to an online cpu. | |
912 | */ | |
913 | smp_call_function_single(cpumask_first(cpu_online_mask), | |
914 | cpuhp_complete_idle_dead, st, 0); | |
e69aab13 TG |
915 | } |
916 | ||
4dddfb5f PZ |
917 | static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
918 | { | |
919 | for (st->state++; st->state < st->target; st->state++) { | |
920 | struct cpuhp_step *step = cpuhp_get_step(st->state); | |
cff7d378 | 921 | |
4dddfb5f PZ |
922 | if (!step->skip_onerr) |
923 | cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); | |
924 | } | |
925 | } | |
926 | ||
927 | static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, | |
928 | enum cpuhp_state target) | |
929 | { | |
930 | enum cpuhp_state prev_state = st->state; | |
931 | int ret = 0; | |
932 | ||
933 | for (; st->state > target; st->state--) { | |
934 | ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); | |
935 | if (ret) { | |
936 | st->target = prev_state; | |
937 | undo_cpu_down(cpu, st); | |
938 | break; | |
939 | } | |
940 | } | |
941 | return ret; | |
942 | } | |
cff7d378 | 943 | |
98458172 | 944 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 TG |
945 | static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
946 | enum cpuhp_state target) | |
98458172 | 947 | { |
cff7d378 TG |
948 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
949 | int prev_state, ret = 0; | |
98458172 TG |
950 | |
951 | if (num_online_cpus() == 1) | |
952 | return -EBUSY; | |
953 | ||
757c989b | 954 | if (!cpu_present(cpu)) |
98458172 TG |
955 | return -EINVAL; |
956 | ||
8f553c49 | 957 | cpus_write_lock(); |
98458172 TG |
958 | |
959 | cpuhp_tasks_frozen = tasks_frozen; | |
960 | ||
4dddfb5f | 961 | prev_state = cpuhp_set_state(st, target); |
1cf4f629 TG |
962 | /* |
963 | * If the current CPU state is in the range of the AP hotplug thread, | |
964 | * then we need to kick the thread. | |
965 | */ | |
8df3e07e | 966 | if (st->state > CPUHP_TEARDOWN_CPU) { |
4dddfb5f | 967 | st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
1cf4f629 TG |
968 | ret = cpuhp_kick_ap_work(cpu); |
969 | /* | |
970 | * The AP side has done the error rollback already. Just | |
971 | * return the error code.. | |
972 | */ | |
973 | if (ret) | |
974 | goto out; | |
975 | ||
976 | /* | |
977 | * We might have stopped still in the range of the AP hotplug | |
978 | * thread. Nothing to do anymore. | |
979 | */ | |
8df3e07e | 980 | if (st->state > CPUHP_TEARDOWN_CPU) |
1cf4f629 | 981 | goto out; |
4dddfb5f PZ |
982 | |
983 | st->target = target; | |
1cf4f629 TG |
984 | } |
985 | /* | |
8df3e07e | 986 | * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
1cf4f629 TG |
987 | * to do the further cleanups. |
988 | */ | |
a724632c | 989 | ret = cpuhp_down_callbacks(cpu, st, target); |
3b9d6da6 | 990 | if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
4dddfb5f PZ |
991 | cpuhp_reset_state(st, prev_state); |
992 | __cpuhp_kick_ap(st); | |
3b9d6da6 | 993 | } |
98458172 | 994 | |
1cf4f629 | 995 | out: |
8f553c49 | 996 | cpus_write_unlock(); |
941154bd TG |
997 | /* |
998 | * Do post unplug cleanup. This is still protected against | |
999 | * concurrent CPU hotplug via cpu_add_remove_lock. | |
1000 | */ | |
1001 | lockup_detector_cleanup(); | |
cff7d378 | 1002 | return ret; |
e3920fb4 RW |
1003 | } |
1004 | ||
cc1fe215 TG |
1005 | static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
1006 | { | |
1007 | if (cpu_hotplug_disabled) | |
1008 | return -EBUSY; | |
1009 | return _cpu_down(cpu, 0, target); | |
1010 | } | |
1011 | ||
af1f4045 | 1012 | static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 | 1013 | { |
9ea09af3 | 1014 | int err; |
e3920fb4 | 1015 | |
d221938c | 1016 | cpu_maps_update_begin(); |
cc1fe215 | 1017 | err = cpu_down_maps_locked(cpu, target); |
d221938c | 1018 | cpu_maps_update_done(); |
1da177e4 LT |
1019 | return err; |
1020 | } | |
4dddfb5f | 1021 | |
af1f4045 TG |
1022 | int cpu_down(unsigned int cpu) |
1023 | { | |
1024 | return do_cpu_down(cpu, CPUHP_OFFLINE); | |
1025 | } | |
b62b8ef9 | 1026 | EXPORT_SYMBOL(cpu_down); |
4dddfb5f PZ |
1027 | |
1028 | #else | |
1029 | #define takedown_cpu NULL | |
1da177e4 LT |
1030 | #endif /*CONFIG_HOTPLUG_CPU*/ |
1031 | ||
4baa0afc | 1032 | /** |
ee1e714b | 1033 | * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
4baa0afc TG |
1034 | * @cpu: cpu that just started |
1035 | * | |
4baa0afc TG |
1036 | * It must be called by the arch code on the new cpu, before the new cpu |
1037 | * enables interrupts and before the "boot" cpu returns from __cpu_up(). | |
1038 | */ | |
1039 | void notify_cpu_starting(unsigned int cpu) | |
1040 | { | |
1041 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1042 | enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); | |
724a8688 | 1043 | int ret; |
4baa0afc | 1044 | |
0c6d4576 | 1045 | rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
0cc3cd21 | 1046 | st->booted_once = true; |
4baa0afc | 1047 | while (st->state < target) { |
4baa0afc | 1048 | st->state++; |
724a8688 PZ |
1049 | ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
1050 | /* | |
1051 | * STARTING must not fail! | |
1052 | */ | |
1053 | WARN_ON_ONCE(ret); | |
4baa0afc TG |
1054 | } |
1055 | } | |
1056 | ||
949338e3 | 1057 | /* |
9cd4f1a4 TG |
1058 | * Called from the idle task. Wake up the controlling task which brings the |
1059 | * stopper and the hotplug thread of the upcoming CPU up and then delegates | |
1060 | * the rest of the online bringup to the hotplug thread. | |
949338e3 | 1061 | */ |
8df3e07e | 1062 | void cpuhp_online_idle(enum cpuhp_state state) |
949338e3 | 1063 | { |
8df3e07e | 1064 | struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
8df3e07e TG |
1065 | |
1066 | /* Happens for the boot cpu */ | |
1067 | if (state != CPUHP_AP_ONLINE_IDLE) | |
1068 | return; | |
1069 | ||
1070 | st->state = CPUHP_AP_ONLINE_IDLE; | |
5ebe7742 | 1071 | complete_ap_thread(st, true); |
949338e3 TG |
1072 | } |
1073 | ||
e3920fb4 | 1074 | /* Requires cpu_add_remove_lock to be held */ |
af1f4045 | 1075 | static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
1da177e4 | 1076 | { |
cff7d378 | 1077 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
3bb5d2ee | 1078 | struct task_struct *idle; |
2e1a3483 | 1079 | int ret = 0; |
1da177e4 | 1080 | |
8f553c49 | 1081 | cpus_write_lock(); |
38498a67 | 1082 | |
757c989b | 1083 | if (!cpu_present(cpu)) { |
5e5041f3 YI |
1084 | ret = -EINVAL; |
1085 | goto out; | |
1086 | } | |
1087 | ||
757c989b TG |
1088 | /* |
1089 | * The caller of do_cpu_up might have raced with another | |
1090 | * caller. Ignore it for now. | |
1091 | */ | |
1092 | if (st->state >= target) | |
38498a67 | 1093 | goto out; |
757c989b TG |
1094 | |
1095 | if (st->state == CPUHP_OFFLINE) { | |
1096 | /* Let it fail before we try to bring the cpu up */ | |
1097 | idle = idle_thread_get(cpu); | |
1098 | if (IS_ERR(idle)) { | |
1099 | ret = PTR_ERR(idle); | |
1100 | goto out; | |
1101 | } | |
3bb5d2ee | 1102 | } |
38498a67 | 1103 | |
ba997462 TG |
1104 | cpuhp_tasks_frozen = tasks_frozen; |
1105 | ||
4dddfb5f | 1106 | cpuhp_set_state(st, target); |
1cf4f629 TG |
1107 | /* |
1108 | * If the current CPU state is in the range of the AP hotplug thread, | |
1109 | * then we need to kick the thread once more. | |
1110 | */ | |
8df3e07e | 1111 | if (st->state > CPUHP_BRINGUP_CPU) { |
1cf4f629 TG |
1112 | ret = cpuhp_kick_ap_work(cpu); |
1113 | /* | |
1114 | * The AP side has done the error rollback already. Just | |
1115 | * return the error code.. | |
1116 | */ | |
1117 | if (ret) | |
1118 | goto out; | |
1119 | } | |
1120 | ||
1121 | /* | |
1122 | * Try to reach the target state. We max out on the BP at | |
8df3e07e | 1123 | * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
1cf4f629 TG |
1124 | * responsible for bringing it up to the target state. |
1125 | */ | |
8df3e07e | 1126 | target = min((int)target, CPUHP_BRINGUP_CPU); |
a724632c | 1127 | ret = cpuhp_up_callbacks(cpu, st, target); |
38498a67 | 1128 | out: |
8f553c49 | 1129 | cpus_write_unlock(); |
e3920fb4 RW |
1130 | return ret; |
1131 | } | |
1132 | ||
af1f4045 | 1133 | static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
e3920fb4 RW |
1134 | { |
1135 | int err = 0; | |
cf23422b | 1136 | |
e0b582ec | 1137 | if (!cpu_possible(cpu)) { |
84117da5 FF |
1138 | pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
1139 | cpu); | |
87d5e023 | 1140 | #if defined(CONFIG_IA64) |
84117da5 | 1141 | pr_err("please check additional_cpus= boot parameter\n"); |
73e753a5 KH |
1142 | #endif |
1143 | return -EINVAL; | |
1144 | } | |
e3920fb4 | 1145 | |
01b0f197 TK |
1146 | err = try_online_node(cpu_to_node(cpu)); |
1147 | if (err) | |
1148 | return err; | |
cf23422b | 1149 | |
d221938c | 1150 | cpu_maps_update_begin(); |
e761b772 MK |
1151 | |
1152 | if (cpu_hotplug_disabled) { | |
e3920fb4 | 1153 | err = -EBUSY; |
e761b772 MK |
1154 | goto out; |
1155 | } | |
05736e4a TG |
1156 | if (!cpu_smt_allowed(cpu)) { |
1157 | err = -EPERM; | |
1158 | goto out; | |
1159 | } | |
e761b772 | 1160 | |
af1f4045 | 1161 | err = _cpu_up(cpu, 0, target); |
e761b772 | 1162 | out: |
d221938c | 1163 | cpu_maps_update_done(); |
e3920fb4 RW |
1164 | return err; |
1165 | } | |
af1f4045 TG |
1166 | |
1167 | int cpu_up(unsigned int cpu) | |
1168 | { | |
1169 | return do_cpu_up(cpu, CPUHP_ONLINE); | |
1170 | } | |
a513f6ba | 1171 | EXPORT_SYMBOL_GPL(cpu_up); |
e3920fb4 | 1172 | |
f3de4be9 | 1173 | #ifdef CONFIG_PM_SLEEP_SMP |
e0b582ec | 1174 | static cpumask_var_t frozen_cpus; |
e3920fb4 | 1175 | |
d391e552 | 1176 | int freeze_secondary_cpus(int primary) |
e3920fb4 | 1177 | { |
d391e552 | 1178 | int cpu, error = 0; |
e3920fb4 | 1179 | |
d221938c | 1180 | cpu_maps_update_begin(); |
d391e552 JM |
1181 | if (!cpu_online(primary)) |
1182 | primary = cpumask_first(cpu_online_mask); | |
9ee349ad XF |
1183 | /* |
1184 | * We take down all of the non-boot CPUs in one shot to avoid races | |
e3920fb4 RW |
1185 | * with the userspace trying to use the CPU hotplug at the same time |
1186 | */ | |
e0b582ec | 1187 | cpumask_clear(frozen_cpus); |
6ad4c188 | 1188 | |
84117da5 | 1189 | pr_info("Disabling non-boot CPUs ...\n"); |
e3920fb4 | 1190 | for_each_online_cpu(cpu) { |
d391e552 | 1191 | if (cpu == primary) |
e3920fb4 | 1192 | continue; |
bb3632c6 | 1193 | trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
af1f4045 | 1194 | error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
bb3632c6 | 1195 | trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
feae3203 | 1196 | if (!error) |
e0b582ec | 1197 | cpumask_set_cpu(cpu, frozen_cpus); |
feae3203 | 1198 | else { |
84117da5 | 1199 | pr_err("Error taking CPU%d down: %d\n", cpu, error); |
e3920fb4 RW |
1200 | break; |
1201 | } | |
1202 | } | |
86886e55 | 1203 | |
89af7ba5 | 1204 | if (!error) |
e3920fb4 | 1205 | BUG_ON(num_online_cpus() > 1); |
89af7ba5 | 1206 | else |
84117da5 | 1207 | pr_err("Non-boot CPUs are not disabled\n"); |
89af7ba5 VK |
1208 | |
1209 | /* | |
1210 | * Make sure the CPUs won't be enabled by someone else. We need to do | |
1211 | * this even in case of failure as all disable_nonboot_cpus() users are | |
1212 | * supposed to do enable_nonboot_cpus() on the failure path. | |
1213 | */ | |
1214 | cpu_hotplug_disabled++; | |
1215 | ||
d221938c | 1216 | cpu_maps_update_done(); |
e3920fb4 RW |
1217 | return error; |
1218 | } | |
1219 | ||
d0af9eed SS |
1220 | void __weak arch_enable_nonboot_cpus_begin(void) |
1221 | { | |
1222 | } | |
1223 | ||
1224 | void __weak arch_enable_nonboot_cpus_end(void) | |
1225 | { | |
1226 | } | |
1227 | ||
71cf5aee | 1228 | void enable_nonboot_cpus(void) |
e3920fb4 RW |
1229 | { |
1230 | int cpu, error; | |
1231 | ||
1232 | /* Allow everyone to use the CPU hotplug again */ | |
d221938c | 1233 | cpu_maps_update_begin(); |
01b41159 | 1234 | __cpu_hotplug_enable(); |
e0b582ec | 1235 | if (cpumask_empty(frozen_cpus)) |
1d64b9cb | 1236 | goto out; |
e3920fb4 | 1237 | |
84117da5 | 1238 | pr_info("Enabling non-boot CPUs ...\n"); |
d0af9eed SS |
1239 | |
1240 | arch_enable_nonboot_cpus_begin(); | |
1241 | ||
e0b582ec | 1242 | for_each_cpu(cpu, frozen_cpus) { |
bb3632c6 | 1243 | trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
af1f4045 | 1244 | error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
bb3632c6 | 1245 | trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
e3920fb4 | 1246 | if (!error) { |
84117da5 | 1247 | pr_info("CPU%d is up\n", cpu); |
e3920fb4 RW |
1248 | continue; |
1249 | } | |
84117da5 | 1250 | pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
e3920fb4 | 1251 | } |
d0af9eed SS |
1252 | |
1253 | arch_enable_nonboot_cpus_end(); | |
1254 | ||
e0b582ec | 1255 | cpumask_clear(frozen_cpus); |
1d64b9cb | 1256 | out: |
d221938c | 1257 | cpu_maps_update_done(); |
1da177e4 | 1258 | } |
e0b582ec | 1259 | |
d7268a31 | 1260 | static int __init alloc_frozen_cpus(void) |
e0b582ec RR |
1261 | { |
1262 | if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) | |
1263 | return -ENOMEM; | |
1264 | return 0; | |
1265 | } | |
1266 | core_initcall(alloc_frozen_cpus); | |
79cfbdfa | 1267 | |
79cfbdfa SB |
1268 | /* |
1269 | * When callbacks for CPU hotplug notifications are being executed, we must | |
1270 | * ensure that the state of the system with respect to the tasks being frozen | |
1271 | * or not, as reported by the notification, remains unchanged *throughout the | |
1272 | * duration* of the execution of the callbacks. | |
1273 | * Hence we need to prevent the freezer from racing with regular CPU hotplug. | |
1274 | * | |
1275 | * This synchronization is implemented by mutually excluding regular CPU | |
1276 | * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ | |
1277 | * Hibernate notifications. | |
1278 | */ | |
1279 | static int | |
1280 | cpu_hotplug_pm_callback(struct notifier_block *nb, | |
1281 | unsigned long action, void *ptr) | |
1282 | { | |
1283 | switch (action) { | |
1284 | ||
1285 | case PM_SUSPEND_PREPARE: | |
1286 | case PM_HIBERNATION_PREPARE: | |
16e53dbf | 1287 | cpu_hotplug_disable(); |
79cfbdfa SB |
1288 | break; |
1289 | ||
1290 | case PM_POST_SUSPEND: | |
1291 | case PM_POST_HIBERNATION: | |
16e53dbf | 1292 | cpu_hotplug_enable(); |
79cfbdfa SB |
1293 | break; |
1294 | ||
1295 | default: | |
1296 | return NOTIFY_DONE; | |
1297 | } | |
1298 | ||
1299 | return NOTIFY_OK; | |
1300 | } | |
1301 | ||
1302 | ||
d7268a31 | 1303 | static int __init cpu_hotplug_pm_sync_init(void) |
79cfbdfa | 1304 | { |
6e32d479 FY |
1305 | /* |
1306 | * cpu_hotplug_pm_callback has higher priority than x86 | |
1307 | * bsp_pm_callback which depends on cpu_hotplug_pm_callback | |
1308 | * to disable cpu hotplug to avoid cpu hotplug race. | |
1309 | */ | |
79cfbdfa SB |
1310 | pm_notifier(cpu_hotplug_pm_callback, 0); |
1311 | return 0; | |
1312 | } | |
1313 | core_initcall(cpu_hotplug_pm_sync_init); | |
1314 | ||
f3de4be9 | 1315 | #endif /* CONFIG_PM_SLEEP_SMP */ |
68f4f1ec | 1316 | |
8ce371f9 PZ |
1317 | int __boot_cpu_id; |
1318 | ||
68f4f1ec | 1319 | #endif /* CONFIG_SMP */ |
b8d317d1 | 1320 | |
cff7d378 | 1321 | /* Boot processor state steps */ |
17a2f1ce | 1322 | static struct cpuhp_step cpuhp_hp_states[] = { |
cff7d378 TG |
1323 | [CPUHP_OFFLINE] = { |
1324 | .name = "offline", | |
3c1627e9 TG |
1325 | .startup.single = NULL, |
1326 | .teardown.single = NULL, | |
cff7d378 TG |
1327 | }, |
1328 | #ifdef CONFIG_SMP | |
1329 | [CPUHP_CREATE_THREADS]= { | |
677f6646 | 1330 | .name = "threads:prepare", |
3c1627e9 TG |
1331 | .startup.single = smpboot_create_threads, |
1332 | .teardown.single = NULL, | |
757c989b | 1333 | .cant_stop = true, |
cff7d378 | 1334 | }, |
00e16c3d | 1335 | [CPUHP_PERF_PREPARE] = { |
3c1627e9 TG |
1336 | .name = "perf:prepare", |
1337 | .startup.single = perf_event_init_cpu, | |
1338 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1339 | }, |
7ee681b2 | 1340 | [CPUHP_WORKQUEUE_PREP] = { |
3c1627e9 TG |
1341 | .name = "workqueue:prepare", |
1342 | .startup.single = workqueue_prepare_cpu, | |
1343 | .teardown.single = NULL, | |
7ee681b2 | 1344 | }, |
27590dc1 | 1345 | [CPUHP_HRTIMERS_PREPARE] = { |
3c1627e9 TG |
1346 | .name = "hrtimers:prepare", |
1347 | .startup.single = hrtimers_prepare_cpu, | |
1348 | .teardown.single = hrtimers_dead_cpu, | |
27590dc1 | 1349 | }, |
31487f83 | 1350 | [CPUHP_SMPCFD_PREPARE] = { |
677f6646 | 1351 | .name = "smpcfd:prepare", |
3c1627e9 TG |
1352 | .startup.single = smpcfd_prepare_cpu, |
1353 | .teardown.single = smpcfd_dead_cpu, | |
31487f83 | 1354 | }, |
e6d4989a RW |
1355 | [CPUHP_RELAY_PREPARE] = { |
1356 | .name = "relay:prepare", | |
1357 | .startup.single = relay_prepare_cpu, | |
1358 | .teardown.single = NULL, | |
1359 | }, | |
6731d4f1 SAS |
1360 | [CPUHP_SLAB_PREPARE] = { |
1361 | .name = "slab:prepare", | |
1362 | .startup.single = slab_prepare_cpu, | |
1363 | .teardown.single = slab_dead_cpu, | |
31487f83 | 1364 | }, |
4df83742 | 1365 | [CPUHP_RCUTREE_PREP] = { |
677f6646 | 1366 | .name = "RCU/tree:prepare", |
3c1627e9 TG |
1367 | .startup.single = rcutree_prepare_cpu, |
1368 | .teardown.single = rcutree_dead_cpu, | |
4df83742 | 1369 | }, |
4fae16df RC |
1370 | /* |
1371 | * On the tear-down path, timers_dead_cpu() must be invoked | |
1372 | * before blk_mq_queue_reinit_notify() from notify_dead(), | |
1373 | * otherwise a RCU stall occurs. | |
1374 | */ | |
26456f87 | 1375 | [CPUHP_TIMERS_PREPARE] = { |
d018031f | 1376 | .name = "timers:prepare", |
26456f87 | 1377 | .startup.single = timers_prepare_cpu, |
3c1627e9 | 1378 | .teardown.single = timers_dead_cpu, |
4fae16df | 1379 | }, |
d10ef6f9 | 1380 | /* Kicks the plugged cpu into life */ |
cff7d378 TG |
1381 | [CPUHP_BRINGUP_CPU] = { |
1382 | .name = "cpu:bringup", | |
3c1627e9 TG |
1383 | .startup.single = bringup_cpu, |
1384 | .teardown.single = NULL, | |
757c989b | 1385 | .cant_stop = true, |
4baa0afc | 1386 | }, |
d10ef6f9 TG |
1387 | /* Final state before CPU kills itself */ |
1388 | [CPUHP_AP_IDLE_DEAD] = { | |
1389 | .name = "idle:dead", | |
1390 | }, | |
1391 | /* | |
1392 | * Last state before CPU enters the idle loop to die. Transient state | |
1393 | * for synchronization. | |
1394 | */ | |
1395 | [CPUHP_AP_OFFLINE] = { | |
1396 | .name = "ap:offline", | |
1397 | .cant_stop = true, | |
1398 | }, | |
9cf7243d TG |
1399 | /* First state is scheduler control. Interrupts are disabled */ |
1400 | [CPUHP_AP_SCHED_STARTING] = { | |
1401 | .name = "sched:starting", | |
3c1627e9 TG |
1402 | .startup.single = sched_cpu_starting, |
1403 | .teardown.single = sched_cpu_dying, | |
9cf7243d | 1404 | }, |
4df83742 | 1405 | [CPUHP_AP_RCUTREE_DYING] = { |
677f6646 | 1406 | .name = "RCU/tree:dying", |
3c1627e9 TG |
1407 | .startup.single = NULL, |
1408 | .teardown.single = rcutree_dying_cpu, | |
4baa0afc | 1409 | }, |
46febd37 LJ |
1410 | [CPUHP_AP_SMPCFD_DYING] = { |
1411 | .name = "smpcfd:dying", | |
1412 | .startup.single = NULL, | |
1413 | .teardown.single = smpcfd_dying_cpu, | |
1414 | }, | |
d10ef6f9 TG |
1415 | /* Entry state on starting. Interrupts enabled from here on. Transient |
1416 | * state for synchronsization */ | |
1417 | [CPUHP_AP_ONLINE] = { | |
1418 | .name = "ap:online", | |
1419 | }, | |
17a2f1ce LJ |
1420 | /* |
1421 | * Handled on controll processor until the plugged processor manages | |
1422 | * this itself. | |
1423 | */ | |
1424 | [CPUHP_TEARDOWN_CPU] = { | |
1425 | .name = "cpu:teardown", | |
1426 | .startup.single = NULL, | |
1427 | .teardown.single = takedown_cpu, | |
1428 | .cant_stop = true, | |
1429 | }, | |
d10ef6f9 | 1430 | /* Handle smpboot threads park/unpark */ |
1cf4f629 | 1431 | [CPUHP_AP_SMPBOOT_THREADS] = { |
677f6646 | 1432 | .name = "smpboot/threads:online", |
3c1627e9 | 1433 | .startup.single = smpboot_unpark_threads, |
c4de6569 | 1434 | .teardown.single = smpboot_park_threads, |
1cf4f629 | 1435 | }, |
c5cb83bb TG |
1436 | [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
1437 | .name = "irq/affinity:online", | |
1438 | .startup.single = irq_affinity_online_cpu, | |
1439 | .teardown.single = NULL, | |
1440 | }, | |
00e16c3d | 1441 | [CPUHP_AP_PERF_ONLINE] = { |
3c1627e9 TG |
1442 | .name = "perf:online", |
1443 | .startup.single = perf_event_init_cpu, | |
1444 | .teardown.single = perf_event_exit_cpu, | |
00e16c3d | 1445 | }, |
9cf57731 PZ |
1446 | [CPUHP_AP_WATCHDOG_ONLINE] = { |
1447 | .name = "lockup_detector:online", | |
1448 | .startup.single = lockup_detector_online_cpu, | |
1449 | .teardown.single = lockup_detector_offline_cpu, | |
1450 | }, | |
7ee681b2 | 1451 | [CPUHP_AP_WORKQUEUE_ONLINE] = { |
3c1627e9 TG |
1452 | .name = "workqueue:online", |
1453 | .startup.single = workqueue_online_cpu, | |
1454 | .teardown.single = workqueue_offline_cpu, | |
7ee681b2 | 1455 | }, |
4df83742 | 1456 | [CPUHP_AP_RCUTREE_ONLINE] = { |
677f6646 | 1457 | .name = "RCU/tree:online", |
3c1627e9 TG |
1458 | .startup.single = rcutree_online_cpu, |
1459 | .teardown.single = rcutree_offline_cpu, | |
4df83742 | 1460 | }, |
4baa0afc | 1461 | #endif |
d10ef6f9 TG |
1462 | /* |
1463 | * The dynamically registered state space is here | |
1464 | */ | |
1465 | ||
aaddd7d1 TG |
1466 | #ifdef CONFIG_SMP |
1467 | /* Last state is scheduler control setting the cpu active */ | |
1468 | [CPUHP_AP_ACTIVE] = { | |
1469 | .name = "sched:active", | |
3c1627e9 TG |
1470 | .startup.single = sched_cpu_activate, |
1471 | .teardown.single = sched_cpu_deactivate, | |
aaddd7d1 TG |
1472 | }, |
1473 | #endif | |
1474 | ||
d10ef6f9 | 1475 | /* CPU is fully up and running. */ |
4baa0afc TG |
1476 | [CPUHP_ONLINE] = { |
1477 | .name = "online", | |
3c1627e9 TG |
1478 | .startup.single = NULL, |
1479 | .teardown.single = NULL, | |
4baa0afc TG |
1480 | }, |
1481 | }; | |
1482 | ||
5b7aa87e TG |
1483 | /* Sanity check for callbacks */ |
1484 | static int cpuhp_cb_check(enum cpuhp_state state) | |
1485 | { | |
1486 | if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) | |
1487 | return -EINVAL; | |
1488 | return 0; | |
1489 | } | |
1490 | ||
dc280d93 TG |
1491 | /* |
1492 | * Returns a free for dynamic slot assignment of the Online state. The states | |
1493 | * are protected by the cpuhp_slot_states mutex and an empty slot is identified | |
1494 | * by having no name assigned. | |
1495 | */ | |
1496 | static int cpuhp_reserve_state(enum cpuhp_state state) | |
1497 | { | |
4205e478 TG |
1498 | enum cpuhp_state i, end; |
1499 | struct cpuhp_step *step; | |
dc280d93 | 1500 | |
4205e478 TG |
1501 | switch (state) { |
1502 | case CPUHP_AP_ONLINE_DYN: | |
17a2f1ce | 1503 | step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN; |
4205e478 TG |
1504 | end = CPUHP_AP_ONLINE_DYN_END; |
1505 | break; | |
1506 | case CPUHP_BP_PREPARE_DYN: | |
17a2f1ce | 1507 | step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN; |
4205e478 TG |
1508 | end = CPUHP_BP_PREPARE_DYN_END; |
1509 | break; | |
1510 | default: | |
1511 | return -EINVAL; | |
1512 | } | |
1513 | ||
1514 | for (i = state; i <= end; i++, step++) { | |
1515 | if (!step->name) | |
dc280d93 TG |
1516 | return i; |
1517 | } | |
1518 | WARN(1, "No more dynamic states available for CPU hotplug\n"); | |
1519 | return -ENOSPC; | |
1520 | } | |
1521 | ||
1522 | static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, | |
1523 | int (*startup)(unsigned int cpu), | |
1524 | int (*teardown)(unsigned int cpu), | |
1525 | bool multi_instance) | |
5b7aa87e TG |
1526 | { |
1527 | /* (Un)Install the callbacks for further cpu hotplug operations */ | |
1528 | struct cpuhp_step *sp; | |
dc280d93 | 1529 | int ret = 0; |
5b7aa87e | 1530 | |
0c96b273 EB |
1531 | /* |
1532 | * If name is NULL, then the state gets removed. | |
1533 | * | |
1534 | * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on | |
1535 | * the first allocation from these dynamic ranges, so the removal | |
1536 | * would trigger a new allocation and clear the wrong (already | |
1537 | * empty) state, leaving the callbacks of the to be cleared state | |
1538 | * dangling, which causes wreckage on the next hotplug operation. | |
1539 | */ | |
1540 | if (name && (state == CPUHP_AP_ONLINE_DYN || | |
1541 | state == CPUHP_BP_PREPARE_DYN)) { | |
dc280d93 TG |
1542 | ret = cpuhp_reserve_state(state); |
1543 | if (ret < 0) | |
dc434e05 | 1544 | return ret; |
dc280d93 TG |
1545 | state = ret; |
1546 | } | |
5b7aa87e | 1547 | sp = cpuhp_get_step(state); |
dc434e05 SAS |
1548 | if (name && sp->name) |
1549 | return -EBUSY; | |
1550 | ||
3c1627e9 TG |
1551 | sp->startup.single = startup; |
1552 | sp->teardown.single = teardown; | |
5b7aa87e | 1553 | sp->name = name; |
cf392d10 TG |
1554 | sp->multi_instance = multi_instance; |
1555 | INIT_HLIST_HEAD(&sp->list); | |
dc280d93 | 1556 | return ret; |
5b7aa87e TG |
1557 | } |
1558 | ||
1559 | static void *cpuhp_get_teardown_cb(enum cpuhp_state state) | |
1560 | { | |
3c1627e9 | 1561 | return cpuhp_get_step(state)->teardown.single; |
5b7aa87e TG |
1562 | } |
1563 | ||
5b7aa87e TG |
1564 | /* |
1565 | * Call the startup/teardown function for a step either on the AP or | |
1566 | * on the current CPU. | |
1567 | */ | |
cf392d10 TG |
1568 | static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
1569 | struct hlist_node *node) | |
5b7aa87e | 1570 | { |
a724632c | 1571 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1572 | int ret; |
1573 | ||
4dddfb5f PZ |
1574 | /* |
1575 | * If there's nothing to do, we done. | |
1576 | * Relies on the union for multi_instance. | |
1577 | */ | |
3c1627e9 TG |
1578 | if ((bringup && !sp->startup.single) || |
1579 | (!bringup && !sp->teardown.single)) | |
5b7aa87e | 1580 | return 0; |
5b7aa87e TG |
1581 | /* |
1582 | * The non AP bound callbacks can fail on bringup. On teardown | |
1583 | * e.g. module removal we crash for now. | |
1584 | */ | |
1cf4f629 TG |
1585 | #ifdef CONFIG_SMP |
1586 | if (cpuhp_is_ap_state(state)) | |
cf392d10 | 1587 | ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
1cf4f629 | 1588 | else |
96abb968 | 1589 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1590 | #else |
96abb968 | 1591 | ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
1cf4f629 | 1592 | #endif |
5b7aa87e TG |
1593 | BUG_ON(ret && !bringup); |
1594 | return ret; | |
1595 | } | |
1596 | ||
1597 | /* | |
1598 | * Called from __cpuhp_setup_state on a recoverable failure. | |
1599 | * | |
1600 | * Note: The teardown callbacks for rollback are not allowed to fail! | |
1601 | */ | |
1602 | static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, | |
cf392d10 | 1603 | struct hlist_node *node) |
5b7aa87e TG |
1604 | { |
1605 | int cpu; | |
1606 | ||
5b7aa87e TG |
1607 | /* Roll back the already executed steps on the other cpus */ |
1608 | for_each_present_cpu(cpu) { | |
1609 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1610 | int cpustate = st->state; | |
1611 | ||
1612 | if (cpu >= failedcpu) | |
1613 | break; | |
1614 | ||
1615 | /* Did we invoke the startup call on that cpu ? */ | |
1616 | if (cpustate >= state) | |
cf392d10 | 1617 | cpuhp_issue_call(cpu, state, false, node); |
5b7aa87e TG |
1618 | } |
1619 | } | |
1620 | ||
9805c673 TG |
1621 | int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
1622 | struct hlist_node *node, | |
1623 | bool invoke) | |
cf392d10 TG |
1624 | { |
1625 | struct cpuhp_step *sp; | |
1626 | int cpu; | |
1627 | int ret; | |
1628 | ||
9805c673 TG |
1629 | lockdep_assert_cpus_held(); |
1630 | ||
cf392d10 TG |
1631 | sp = cpuhp_get_step(state); |
1632 | if (sp->multi_instance == false) | |
1633 | return -EINVAL; | |
1634 | ||
dc434e05 | 1635 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 | 1636 | |
3c1627e9 | 1637 | if (!invoke || !sp->startup.multi) |
cf392d10 TG |
1638 | goto add_node; |
1639 | ||
1640 | /* | |
1641 | * Try to call the startup callback for each present cpu | |
1642 | * depending on the hotplug state of the cpu. | |
1643 | */ | |
1644 | for_each_present_cpu(cpu) { | |
1645 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1646 | int cpustate = st->state; | |
1647 | ||
1648 | if (cpustate < state) | |
1649 | continue; | |
1650 | ||
1651 | ret = cpuhp_issue_call(cpu, state, true, node); | |
1652 | if (ret) { | |
3c1627e9 | 1653 | if (sp->teardown.multi) |
cf392d10 | 1654 | cpuhp_rollback_install(cpu, state, node); |
dc434e05 | 1655 | goto unlock; |
cf392d10 TG |
1656 | } |
1657 | } | |
1658 | add_node: | |
1659 | ret = 0; | |
cf392d10 | 1660 | hlist_add_head(node, &sp->list); |
dc434e05 | 1661 | unlock: |
cf392d10 | 1662 | mutex_unlock(&cpuhp_state_mutex); |
9805c673 TG |
1663 | return ret; |
1664 | } | |
1665 | ||
1666 | int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, | |
1667 | bool invoke) | |
1668 | { | |
1669 | int ret; | |
1670 | ||
1671 | cpus_read_lock(); | |
1672 | ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); | |
8f553c49 | 1673 | cpus_read_unlock(); |
cf392d10 TG |
1674 | return ret; |
1675 | } | |
1676 | EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); | |
1677 | ||
5b7aa87e | 1678 | /** |
71def423 | 1679 | * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
dc280d93 TG |
1680 | * @state: The state to setup |
1681 | * @invoke: If true, the startup function is invoked for cpus where | |
1682 | * cpu state >= @state | |
1683 | * @startup: startup callback function | |
1684 | * @teardown: teardown callback function | |
1685 | * @multi_instance: State is set up for multiple instances which get | |
1686 | * added afterwards. | |
5b7aa87e | 1687 | * |
71def423 | 1688 | * The caller needs to hold cpus read locked while calling this function. |
512f0980 BO |
1689 | * Returns: |
1690 | * On success: | |
1691 | * Positive state number if @state is CPUHP_AP_ONLINE_DYN | |
1692 | * 0 for all other states | |
1693 | * On failure: proper (negative) error code | |
5b7aa87e | 1694 | */ |
71def423 SAS |
1695 | int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
1696 | const char *name, bool invoke, | |
1697 | int (*startup)(unsigned int cpu), | |
1698 | int (*teardown)(unsigned int cpu), | |
1699 | bool multi_instance) | |
5b7aa87e TG |
1700 | { |
1701 | int cpu, ret = 0; | |
b9d9d691 | 1702 | bool dynstate; |
5b7aa87e | 1703 | |
71def423 SAS |
1704 | lockdep_assert_cpus_held(); |
1705 | ||
5b7aa87e TG |
1706 | if (cpuhp_cb_check(state) || !name) |
1707 | return -EINVAL; | |
1708 | ||
dc434e05 | 1709 | mutex_lock(&cpuhp_state_mutex); |
5b7aa87e | 1710 | |
dc280d93 TG |
1711 | ret = cpuhp_store_callbacks(state, name, startup, teardown, |
1712 | multi_instance); | |
5b7aa87e | 1713 | |
b9d9d691 TG |
1714 | dynstate = state == CPUHP_AP_ONLINE_DYN; |
1715 | if (ret > 0 && dynstate) { | |
1716 | state = ret; | |
1717 | ret = 0; | |
1718 | } | |
1719 | ||
dc280d93 | 1720 | if (ret || !invoke || !startup) |
5b7aa87e TG |
1721 | goto out; |
1722 | ||
1723 | /* | |
1724 | * Try to call the startup callback for each present cpu | |
1725 | * depending on the hotplug state of the cpu. | |
1726 | */ | |
1727 | for_each_present_cpu(cpu) { | |
1728 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1729 | int cpustate = st->state; | |
1730 | ||
1731 | if (cpustate < state) | |
1732 | continue; | |
1733 | ||
cf392d10 | 1734 | ret = cpuhp_issue_call(cpu, state, true, NULL); |
5b7aa87e | 1735 | if (ret) { |
a724632c | 1736 | if (teardown) |
cf392d10 TG |
1737 | cpuhp_rollback_install(cpu, state, NULL); |
1738 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); | |
5b7aa87e TG |
1739 | goto out; |
1740 | } | |
1741 | } | |
1742 | out: | |
dc434e05 | 1743 | mutex_unlock(&cpuhp_state_mutex); |
dc280d93 TG |
1744 | /* |
1745 | * If the requested state is CPUHP_AP_ONLINE_DYN, return the | |
1746 | * dynamically allocated state in case of success. | |
1747 | */ | |
b9d9d691 | 1748 | if (!ret && dynstate) |
5b7aa87e TG |
1749 | return state; |
1750 | return ret; | |
1751 | } | |
71def423 SAS |
1752 | EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
1753 | ||
1754 | int __cpuhp_setup_state(enum cpuhp_state state, | |
1755 | const char *name, bool invoke, | |
1756 | int (*startup)(unsigned int cpu), | |
1757 | int (*teardown)(unsigned int cpu), | |
1758 | bool multi_instance) | |
1759 | { | |
1760 | int ret; | |
1761 | ||
1762 | cpus_read_lock(); | |
1763 | ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, | |
1764 | teardown, multi_instance); | |
1765 | cpus_read_unlock(); | |
1766 | return ret; | |
1767 | } | |
5b7aa87e TG |
1768 | EXPORT_SYMBOL(__cpuhp_setup_state); |
1769 | ||
cf392d10 TG |
1770 | int __cpuhp_state_remove_instance(enum cpuhp_state state, |
1771 | struct hlist_node *node, bool invoke) | |
1772 | { | |
1773 | struct cpuhp_step *sp = cpuhp_get_step(state); | |
1774 | int cpu; | |
1775 | ||
1776 | BUG_ON(cpuhp_cb_check(state)); | |
1777 | ||
1778 | if (!sp->multi_instance) | |
1779 | return -EINVAL; | |
1780 | ||
8f553c49 | 1781 | cpus_read_lock(); |
dc434e05 SAS |
1782 | mutex_lock(&cpuhp_state_mutex); |
1783 | ||
cf392d10 TG |
1784 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
1785 | goto remove; | |
1786 | /* | |
1787 | * Call the teardown callback for each present cpu depending | |
1788 | * on the hotplug state of the cpu. This function is not | |
1789 | * allowed to fail currently! | |
1790 | */ | |
1791 | for_each_present_cpu(cpu) { | |
1792 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1793 | int cpustate = st->state; | |
1794 | ||
1795 | if (cpustate >= state) | |
1796 | cpuhp_issue_call(cpu, state, false, node); | |
1797 | } | |
1798 | ||
1799 | remove: | |
cf392d10 TG |
1800 | hlist_del(node); |
1801 | mutex_unlock(&cpuhp_state_mutex); | |
8f553c49 | 1802 | cpus_read_unlock(); |
cf392d10 TG |
1803 | |
1804 | return 0; | |
1805 | } | |
1806 | EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); | |
dc434e05 | 1807 | |
5b7aa87e | 1808 | /** |
71def423 | 1809 | * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
5b7aa87e TG |
1810 | * @state: The state to remove |
1811 | * @invoke: If true, the teardown function is invoked for cpus where | |
1812 | * cpu state >= @state | |
1813 | * | |
71def423 | 1814 | * The caller needs to hold cpus read locked while calling this function. |
5b7aa87e TG |
1815 | * The teardown callback is currently not allowed to fail. Think |
1816 | * about module removal! | |
1817 | */ | |
71def423 | 1818 | void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
5b7aa87e | 1819 | { |
cf392d10 | 1820 | struct cpuhp_step *sp = cpuhp_get_step(state); |
5b7aa87e TG |
1821 | int cpu; |
1822 | ||
1823 | BUG_ON(cpuhp_cb_check(state)); | |
1824 | ||
71def423 | 1825 | lockdep_assert_cpus_held(); |
5b7aa87e | 1826 | |
dc434e05 | 1827 | mutex_lock(&cpuhp_state_mutex); |
cf392d10 TG |
1828 | if (sp->multi_instance) { |
1829 | WARN(!hlist_empty(&sp->list), | |
1830 | "Error: Removing state %d which has instances left.\n", | |
1831 | state); | |
1832 | goto remove; | |
1833 | } | |
1834 | ||
a724632c | 1835 | if (!invoke || !cpuhp_get_teardown_cb(state)) |
5b7aa87e TG |
1836 | goto remove; |
1837 | ||
1838 | /* | |
1839 | * Call the teardown callback for each present cpu depending | |
1840 | * on the hotplug state of the cpu. This function is not | |
1841 | * allowed to fail currently! | |
1842 | */ | |
1843 | for_each_present_cpu(cpu) { | |
1844 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); | |
1845 | int cpustate = st->state; | |
1846 | ||
1847 | if (cpustate >= state) | |
cf392d10 | 1848 | cpuhp_issue_call(cpu, state, false, NULL); |
5b7aa87e TG |
1849 | } |
1850 | remove: | |
cf392d10 | 1851 | cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
dc434e05 | 1852 | mutex_unlock(&cpuhp_state_mutex); |
71def423 SAS |
1853 | } |
1854 | EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); | |
1855 | ||
1856 | void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) | |
1857 | { | |
1858 | cpus_read_lock(); | |
1859 | __cpuhp_remove_state_cpuslocked(state, invoke); | |
8f553c49 | 1860 | cpus_read_unlock(); |
5b7aa87e TG |
1861 | } |
1862 | EXPORT_SYMBOL(__cpuhp_remove_state); | |
1863 | ||
98f8cdce TG |
1864 | #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
1865 | static ssize_t show_cpuhp_state(struct device *dev, | |
1866 | struct device_attribute *attr, char *buf) | |
1867 | { | |
1868 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1869 | ||
1870 | return sprintf(buf, "%d\n", st->state); | |
1871 | } | |
1872 | static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); | |
1873 | ||
757c989b TG |
1874 | static ssize_t write_cpuhp_target(struct device *dev, |
1875 | struct device_attribute *attr, | |
1876 | const char *buf, size_t count) | |
1877 | { | |
1878 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1879 | struct cpuhp_step *sp; | |
1880 | int target, ret; | |
1881 | ||
1882 | ret = kstrtoint(buf, 10, &target); | |
1883 | if (ret) | |
1884 | return ret; | |
1885 | ||
1886 | #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL | |
1887 | if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) | |
1888 | return -EINVAL; | |
1889 | #else | |
1890 | if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) | |
1891 | return -EINVAL; | |
1892 | #endif | |
1893 | ||
1894 | ret = lock_device_hotplug_sysfs(); | |
1895 | if (ret) | |
1896 | return ret; | |
1897 | ||
1898 | mutex_lock(&cpuhp_state_mutex); | |
1899 | sp = cpuhp_get_step(target); | |
1900 | ret = !sp->name || sp->cant_stop ? -EINVAL : 0; | |
1901 | mutex_unlock(&cpuhp_state_mutex); | |
1902 | if (ret) | |
40da1b11 | 1903 | goto out; |
757c989b TG |
1904 | |
1905 | if (st->state < target) | |
1906 | ret = do_cpu_up(dev->id, target); | |
1907 | else | |
1908 | ret = do_cpu_down(dev->id, target); | |
40da1b11 | 1909 | out: |
757c989b TG |
1910 | unlock_device_hotplug(); |
1911 | return ret ? ret : count; | |
1912 | } | |
1913 | ||
98f8cdce TG |
1914 | static ssize_t show_cpuhp_target(struct device *dev, |
1915 | struct device_attribute *attr, char *buf) | |
1916 | { | |
1917 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1918 | ||
1919 | return sprintf(buf, "%d\n", st->target); | |
1920 | } | |
757c989b | 1921 | static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
98f8cdce | 1922 | |
1db49484 PZ |
1923 | |
1924 | static ssize_t write_cpuhp_fail(struct device *dev, | |
1925 | struct device_attribute *attr, | |
1926 | const char *buf, size_t count) | |
1927 | { | |
1928 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1929 | struct cpuhp_step *sp; | |
1930 | int fail, ret; | |
1931 | ||
1932 | ret = kstrtoint(buf, 10, &fail); | |
1933 | if (ret) | |
1934 | return ret; | |
1935 | ||
1936 | /* | |
1937 | * Cannot fail STARTING/DYING callbacks. | |
1938 | */ | |
1939 | if (cpuhp_is_atomic_state(fail)) | |
1940 | return -EINVAL; | |
1941 | ||
1942 | /* | |
1943 | * Cannot fail anything that doesn't have callbacks. | |
1944 | */ | |
1945 | mutex_lock(&cpuhp_state_mutex); | |
1946 | sp = cpuhp_get_step(fail); | |
1947 | if (!sp->startup.single && !sp->teardown.single) | |
1948 | ret = -EINVAL; | |
1949 | mutex_unlock(&cpuhp_state_mutex); | |
1950 | if (ret) | |
1951 | return ret; | |
1952 | ||
1953 | st->fail = fail; | |
1954 | ||
1955 | return count; | |
1956 | } | |
1957 | ||
1958 | static ssize_t show_cpuhp_fail(struct device *dev, | |
1959 | struct device_attribute *attr, char *buf) | |
1960 | { | |
1961 | struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); | |
1962 | ||
1963 | return sprintf(buf, "%d\n", st->fail); | |
1964 | } | |
1965 | ||
1966 | static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); | |
1967 | ||
98f8cdce TG |
1968 | static struct attribute *cpuhp_cpu_attrs[] = { |
1969 | &dev_attr_state.attr, | |
1970 | &dev_attr_target.attr, | |
1db49484 | 1971 | &dev_attr_fail.attr, |
98f8cdce TG |
1972 | NULL |
1973 | }; | |
1974 | ||
993647a2 | 1975 | static const struct attribute_group cpuhp_cpu_attr_group = { |
98f8cdce TG |
1976 | .attrs = cpuhp_cpu_attrs, |
1977 | .name = "hotplug", | |
1978 | NULL | |
1979 | }; | |
1980 | ||
1981 | static ssize_t show_cpuhp_states(struct device *dev, | |
1982 | struct device_attribute *attr, char *buf) | |
1983 | { | |
1984 | ssize_t cur, res = 0; | |
1985 | int i; | |
1986 | ||
1987 | mutex_lock(&cpuhp_state_mutex); | |
757c989b | 1988 | for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
98f8cdce TG |
1989 | struct cpuhp_step *sp = cpuhp_get_step(i); |
1990 | ||
1991 | if (sp->name) { | |
1992 | cur = sprintf(buf, "%3d: %s\n", i, sp->name); | |
1993 | buf += cur; | |
1994 | res += cur; | |
1995 | } | |
1996 | } | |
1997 | mutex_unlock(&cpuhp_state_mutex); | |
1998 | return res; | |
1999 | } | |
2000 | static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); | |
2001 | ||
2002 | static struct attribute *cpuhp_cpu_root_attrs[] = { | |
2003 | &dev_attr_states.attr, | |
2004 | NULL | |
2005 | }; | |
2006 | ||
993647a2 | 2007 | static const struct attribute_group cpuhp_cpu_root_attr_group = { |
98f8cdce TG |
2008 | .attrs = cpuhp_cpu_root_attrs, |
2009 | .name = "hotplug", | |
2010 | NULL | |
2011 | }; | |
2012 | ||
05736e4a TG |
2013 | #ifdef CONFIG_HOTPLUG_SMT |
2014 | ||
2015 | static const char *smt_states[] = { | |
2016 | [CPU_SMT_ENABLED] = "on", | |
2017 | [CPU_SMT_DISABLED] = "off", | |
2018 | [CPU_SMT_FORCE_DISABLED] = "forceoff", | |
2019 | [CPU_SMT_NOT_SUPPORTED] = "notsupported", | |
2020 | }; | |
2021 | ||
2022 | static ssize_t | |
2023 | show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) | |
2024 | { | |
2025 | return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); | |
2026 | } | |
2027 | ||
2028 | static void cpuhp_offline_cpu_device(unsigned int cpu) | |
2029 | { | |
2030 | struct device *dev = get_cpu_device(cpu); | |
2031 | ||
2032 | dev->offline = true; | |
2033 | /* Tell user space about the state change */ | |
2034 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); | |
2035 | } | |
2036 | ||
215af549 TG |
2037 | static void cpuhp_online_cpu_device(unsigned int cpu) |
2038 | { | |
2039 | struct device *dev = get_cpu_device(cpu); | |
2040 | ||
2041 | dev->offline = false; | |
2042 | /* Tell user space about the state change */ | |
2043 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); | |
2044 | } | |
2045 | ||
05736e4a TG |
2046 | static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) |
2047 | { | |
2048 | int cpu, ret = 0; | |
2049 | ||
2050 | cpu_maps_update_begin(); | |
2051 | for_each_online_cpu(cpu) { | |
2052 | if (topology_is_primary_thread(cpu)) | |
2053 | continue; | |
2054 | ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE); | |
2055 | if (ret) | |
2056 | break; | |
2057 | /* | |
2058 | * As this needs to hold the cpu maps lock it's impossible | |
2059 | * to call device_offline() because that ends up calling | |
2060 | * cpu_down() which takes cpu maps lock. cpu maps lock | |
2061 | * needs to be held as this might race against in kernel | |
2062 | * abusers of the hotplug machinery (thermal management). | |
2063 | * | |
2064 | * So nothing would update device:offline state. That would | |
2065 | * leave the sysfs entry stale and prevent onlining after | |
2066 | * smt control has been changed to 'off' again. This is | |
2067 | * called under the sysfs hotplug lock, so it is properly | |
2068 | * serialized against the regular offline usage. | |
2069 | */ | |
2070 | cpuhp_offline_cpu_device(cpu); | |
2071 | } | |
2072 | if (!ret) | |
2073 | cpu_smt_control = ctrlval; | |
2074 | cpu_maps_update_done(); | |
2075 | return ret; | |
2076 | } | |
2077 | ||
215af549 | 2078 | static int cpuhp_smt_enable(void) |
05736e4a | 2079 | { |
215af549 TG |
2080 | int cpu, ret = 0; |
2081 | ||
05736e4a TG |
2082 | cpu_maps_update_begin(); |
2083 | cpu_smt_control = CPU_SMT_ENABLED; | |
215af549 TG |
2084 | for_each_present_cpu(cpu) { |
2085 | /* Skip online CPUs and CPUs on offline nodes */ | |
2086 | if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) | |
2087 | continue; | |
2088 | ret = _cpu_up(cpu, 0, CPUHP_ONLINE); | |
2089 | if (ret) | |
2090 | break; | |
2091 | /* See comment in cpuhp_smt_disable() */ | |
2092 | cpuhp_online_cpu_device(cpu); | |
2093 | } | |
05736e4a | 2094 | cpu_maps_update_done(); |
215af549 | 2095 | return ret; |
05736e4a TG |
2096 | } |
2097 | ||
2098 | static ssize_t | |
2099 | store_smt_control(struct device *dev, struct device_attribute *attr, | |
2100 | const char *buf, size_t count) | |
2101 | { | |
2102 | int ctrlval, ret; | |
2103 | ||
2104 | if (sysfs_streq(buf, "on")) | |
2105 | ctrlval = CPU_SMT_ENABLED; | |
2106 | else if (sysfs_streq(buf, "off")) | |
2107 | ctrlval = CPU_SMT_DISABLED; | |
2108 | else if (sysfs_streq(buf, "forceoff")) | |
2109 | ctrlval = CPU_SMT_FORCE_DISABLED; | |
2110 | else | |
2111 | return -EINVAL; | |
2112 | ||
2113 | if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) | |
2114 | return -EPERM; | |
2115 | ||
2116 | if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) | |
2117 | return -ENODEV; | |
2118 | ||
2119 | ret = lock_device_hotplug_sysfs(); | |
2120 | if (ret) | |
2121 | return ret; | |
2122 | ||
2123 | if (ctrlval != cpu_smt_control) { | |
2124 | switch (ctrlval) { | |
2125 | case CPU_SMT_ENABLED: | |
215af549 | 2126 | ret = cpuhp_smt_enable(); |
05736e4a TG |
2127 | break; |
2128 | case CPU_SMT_DISABLED: | |
2129 | case CPU_SMT_FORCE_DISABLED: | |
2130 | ret = cpuhp_smt_disable(ctrlval); | |
2131 | break; | |
2132 | } | |
2133 | } | |
2134 | ||
2135 | unlock_device_hotplug(); | |
2136 | return ret ? ret : count; | |
2137 | } | |
2138 | static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); | |
2139 | ||
2140 | static ssize_t | |
2141 | show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) | |
2142 | { | |
2143 | bool active = topology_max_smt_threads() > 1; | |
2144 | ||
2145 | return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); | |
2146 | } | |
2147 | static DEVICE_ATTR(active, 0444, show_smt_active, NULL); | |
2148 | ||
2149 | static struct attribute *cpuhp_smt_attrs[] = { | |
2150 | &dev_attr_control.attr, | |
2151 | &dev_attr_active.attr, | |
2152 | NULL | |
2153 | }; | |
2154 | ||
2155 | static const struct attribute_group cpuhp_smt_attr_group = { | |
2156 | .attrs = cpuhp_smt_attrs, | |
2157 | .name = "smt", | |
2158 | NULL | |
2159 | }; | |
2160 | ||
2161 | static int __init cpu_smt_state_init(void) | |
2162 | { | |
05736e4a TG |
2163 | return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2164 | &cpuhp_smt_attr_group); | |
2165 | } | |
2166 | ||
2167 | #else | |
2168 | static inline int cpu_smt_state_init(void) { return 0; } | |
2169 | #endif | |
2170 | ||
98f8cdce TG |
2171 | static int __init cpuhp_sysfs_init(void) |
2172 | { | |
2173 | int cpu, ret; | |
2174 | ||
05736e4a TG |
2175 | ret = cpu_smt_state_init(); |
2176 | if (ret) | |
2177 | return ret; | |
2178 | ||
98f8cdce TG |
2179 | ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
2180 | &cpuhp_cpu_root_attr_group); | |
2181 | if (ret) | |
2182 | return ret; | |
2183 | ||
2184 | for_each_possible_cpu(cpu) { | |
2185 | struct device *dev = get_cpu_device(cpu); | |
2186 | ||
2187 | if (!dev) | |
2188 | continue; | |
2189 | ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); | |
2190 | if (ret) | |
2191 | return ret; | |
2192 | } | |
2193 | return 0; | |
2194 | } | |
2195 | device_initcall(cpuhp_sysfs_init); | |
2196 | #endif | |
2197 | ||
e56b3bc7 LT |
2198 | /* |
2199 | * cpu_bit_bitmap[] is a special, "compressed" data structure that | |
2200 | * represents all NR_CPUS bits binary values of 1<<nr. | |
2201 | * | |
e0b582ec | 2202 | * It is used by cpumask_of() to get a constant address to a CPU |
e56b3bc7 LT |
2203 | * mask value that has a single bit set only. |
2204 | */ | |
b8d317d1 | 2205 | |
e56b3bc7 | 2206 | /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
4d51985e | 2207 | #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
e56b3bc7 LT |
2208 | #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
2209 | #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) | |
2210 | #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) | |
b8d317d1 | 2211 | |
e56b3bc7 LT |
2212 | const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
2213 | ||
2214 | MASK_DECLARE_8(0), MASK_DECLARE_8(8), | |
2215 | MASK_DECLARE_8(16), MASK_DECLARE_8(24), | |
2216 | #if BITS_PER_LONG > 32 | |
2217 | MASK_DECLARE_8(32), MASK_DECLARE_8(40), | |
2218 | MASK_DECLARE_8(48), MASK_DECLARE_8(56), | |
b8d317d1 MT |
2219 | #endif |
2220 | }; | |
e56b3bc7 | 2221 | EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
2d3854a3 RR |
2222 | |
2223 | const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; | |
2224 | EXPORT_SYMBOL(cpu_all_bits); | |
b3199c02 RR |
2225 | |
2226 | #ifdef CONFIG_INIT_ALL_POSSIBLE | |
4b804c85 | 2227 | struct cpumask __cpu_possible_mask __read_mostly |
c4c54dd1 | 2228 | = {CPU_BITS_ALL}; |
b3199c02 | 2229 | #else |
4b804c85 | 2230 | struct cpumask __cpu_possible_mask __read_mostly; |
b3199c02 | 2231 | #endif |
4b804c85 | 2232 | EXPORT_SYMBOL(__cpu_possible_mask); |
b3199c02 | 2233 | |
4b804c85 RV |
2234 | struct cpumask __cpu_online_mask __read_mostly; |
2235 | EXPORT_SYMBOL(__cpu_online_mask); | |
b3199c02 | 2236 | |
4b804c85 RV |
2237 | struct cpumask __cpu_present_mask __read_mostly; |
2238 | EXPORT_SYMBOL(__cpu_present_mask); | |
b3199c02 | 2239 | |
4b804c85 RV |
2240 | struct cpumask __cpu_active_mask __read_mostly; |
2241 | EXPORT_SYMBOL(__cpu_active_mask); | |
3fa41520 | 2242 | |
3fa41520 RR |
2243 | void init_cpu_present(const struct cpumask *src) |
2244 | { | |
c4c54dd1 | 2245 | cpumask_copy(&__cpu_present_mask, src); |
3fa41520 RR |
2246 | } |
2247 | ||
2248 | void init_cpu_possible(const struct cpumask *src) | |
2249 | { | |
c4c54dd1 | 2250 | cpumask_copy(&__cpu_possible_mask, src); |
3fa41520 RR |
2251 | } |
2252 | ||
2253 | void init_cpu_online(const struct cpumask *src) | |
2254 | { | |
c4c54dd1 | 2255 | cpumask_copy(&__cpu_online_mask, src); |
3fa41520 | 2256 | } |
cff7d378 TG |
2257 | |
2258 | /* | |
2259 | * Activate the first processor. | |
2260 | */ | |
2261 | void __init boot_cpu_init(void) | |
2262 | { | |
2263 | int cpu = smp_processor_id(); | |
2264 | ||
2265 | /* Mark the boot cpu "present", "online" etc for SMP and UP case */ | |
2266 | set_cpu_online(cpu, true); | |
2267 | set_cpu_active(cpu, true); | |
2268 | set_cpu_present(cpu, true); | |
2269 | set_cpu_possible(cpu, true); | |
8ce371f9 PZ |
2270 | |
2271 | #ifdef CONFIG_SMP | |
2272 | __boot_cpu_id = cpu; | |
2273 | #endif | |
cff7d378 TG |
2274 | } |
2275 | ||
2276 | /* | |
2277 | * Must be called _AFTER_ setting up the per_cpu areas | |
2278 | */ | |
b5b1404d | 2279 | void __init boot_cpu_hotplug_init(void) |
cff7d378 | 2280 | { |
269777aa | 2281 | #ifdef CONFIG_SMP |
0cc3cd21 | 2282 | this_cpu_write(cpuhp_state.booted_once, true); |
269777aa | 2283 | #endif |
0cc3cd21 | 2284 | this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
cff7d378 | 2285 | } |