1 /* CPU control. 1 /* CPU control.
2 * (C) 2001, 2002, 2003, 2004 Rusty Russell 2 * (C) 2001, 2002, 2003, 2004 Rusty Russell
3 * 3 *
4 * This code is licenced under the GPL. 4 * This code is licenced under the GPL.
5 */ 5 */
6 #include <linux/sched/mm.h> <<
7 #include <linux/proc_fs.h> 6 #include <linux/proc_fs.h>
8 #include <linux/smp.h> 7 #include <linux/smp.h>
9 #include <linux/init.h> 8 #include <linux/init.h>
10 #include <linux/notifier.h> 9 #include <linux/notifier.h>
11 #include <linux/sched/signal.h> 10 #include <linux/sched/signal.h>
12 #include <linux/sched/hotplug.h> 11 #include <linux/sched/hotplug.h>
13 #include <linux/sched/isolation.h> <<
14 #include <linux/sched/task.h> 12 #include <linux/sched/task.h>
15 #include <linux/sched/smt.h> <<
16 #include <linux/unistd.h> 13 #include <linux/unistd.h>
17 #include <linux/cpu.h> 14 #include <linux/cpu.h>
18 #include <linux/oom.h> 15 #include <linux/oom.h>
19 #include <linux/rcupdate.h> 16 #include <linux/rcupdate.h>
20 #include <linux/delay.h> <<
21 #include <linux/export.h> 17 #include <linux/export.h>
22 #include <linux/bug.h> 18 #include <linux/bug.h>
23 #include <linux/kthread.h> 19 #include <linux/kthread.h>
24 #include <linux/stop_machine.h> 20 #include <linux/stop_machine.h>
25 #include <linux/mutex.h> 21 #include <linux/mutex.h>
26 #include <linux/gfp.h> 22 #include <linux/gfp.h>
27 #include <linux/suspend.h> 23 #include <linux/suspend.h>
28 #include <linux/lockdep.h> 24 #include <linux/lockdep.h>
29 #include <linux/tick.h> 25 #include <linux/tick.h>
30 #include <linux/irq.h> 26 #include <linux/irq.h>
31 #include <linux/nmi.h> <<
32 #include <linux/smpboot.h> 27 #include <linux/smpboot.h>
33 #include <linux/relay.h> 28 #include <linux/relay.h>
34 #include <linux/slab.h> 29 #include <linux/slab.h>
35 #include <linux/scs.h> <<
36 #include <linux/percpu-rwsem.h> <<
37 #include <linux/cpuset.h> <<
38 #include <linux/random.h> <<
39 #include <linux/cc_platform.h> <<
40 30
41 #include <trace/events/power.h> 31 #include <trace/events/power.h>
42 #define CREATE_TRACE_POINTS 32 #define CREATE_TRACE_POINTS
43 #include <trace/events/cpuhp.h> 33 #include <trace/events/cpuhp.h>
44 34
45 #include "smpboot.h" 35 #include "smpboot.h"
46 36
47 /** 37 /**
48 * struct cpuhp_cpu_state - Per cpu hotplug st !! 38 * cpuhp_cpu_state - Per cpu hotplug state storage
49 * @state: The current cpu state 39 * @state: The current cpu state
50 * @target: The target state 40 * @target: The target state
51 * @fail: Current CPU hotplug callback s <<
52 * @thread: Pointer to the hotplug thread 41 * @thread: Pointer to the hotplug thread
53 * @should_run: Thread should execute 42 * @should_run: Thread should execute
54 * @rollback: Perform a rollback 43 * @rollback: Perform a rollback
55 * @single: Single callback invocation 44 * @single: Single callback invocation
56 * @bringup: Single callback bringup or tea 45 * @bringup: Single callback bringup or teardown selector
57 * @node: Remote CPU node; for multi-ins <<
58 * single entry callback for inst <<
59 * @last: For multi-instance rollback, r <<
60 * @cb_state: The state for a single callbac 46 * @cb_state: The state for a single callback (install/uninstall)
61 * @result: Result of the operation 47 * @result: Result of the operation
62 * @ap_sync_state: State for AP synchroni !! 48 * @done: Signal completion to the issuer of the task
63 * @done_up: Signal completion to the issue <<
64 * @done_down: Signal completion to the issue <<
65 */ 49 */
66 struct cpuhp_cpu_state { 50 struct cpuhp_cpu_state {
67 enum cpuhp_state state; 51 enum cpuhp_state state;
68 enum cpuhp_state target; 52 enum cpuhp_state target;
69 enum cpuhp_state fail; <<
70 #ifdef CONFIG_SMP 53 #ifdef CONFIG_SMP
71 struct task_struct *thread; 54 struct task_struct *thread;
72 bool should_run; 55 bool should_run;
73 bool rollback; 56 bool rollback;
74 bool single; 57 bool single;
75 bool bringup; 58 bool bringup;
76 struct hlist_node *node; 59 struct hlist_node *node;
77 struct hlist_node *last; <<
78 enum cpuhp_state cb_state; 60 enum cpuhp_state cb_state;
79 int result; 61 int result;
80 atomic_t ap_sync_state; !! 62 struct completion done;
81 struct completion done_up; <<
82 struct completion done_down; <<
83 #endif 63 #endif
84 }; 64 };
85 65
86 static DEFINE_PER_CPU(struct cpuhp_cpu_state, !! 66 static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state);
87 .fail = CPUHP_INVALID, <<
88 }; <<
89 <<
90 #ifdef CONFIG_SMP <<
91 cpumask_t cpus_booted_once_mask; <<
92 #endif <<
93 <<
94 #if defined(CONFIG_LOCKDEP) && defined(CONFIG_ <<
95 static struct lockdep_map cpuhp_state_up_map = <<
96 STATIC_LOCKDEP_MAP_INIT("cpuhp_state-u <<
97 static struct lockdep_map cpuhp_state_down_map <<
98 STATIC_LOCKDEP_MAP_INIT("cpuhp_state-d <<
99 <<
100 <<
101 static inline void cpuhp_lock_acquire(bool bri <<
102 { <<
103 lock_map_acquire(bringup ? &cpuhp_stat <<
104 } <<
105 <<
106 static inline void cpuhp_lock_release(bool bri <<
107 { <<
108 lock_map_release(bringup ? &cpuhp_stat <<
109 } <<
110 #else <<
111 <<
112 static inline void cpuhp_lock_acquire(bool bri <<
113 static inline void cpuhp_lock_release(bool bri <<
114 <<
115 #endif <<
116 67
117 /** 68 /**
118 * struct cpuhp_step - Hotplug state machine s !! 69 * cpuhp_step - Hotplug state machine step
119 * @name: Name of the step 70 * @name: Name of the step
120 * @startup: Startup function of the step 71 * @startup: Startup function of the step
121 * @teardown: Teardown function of the step 72 * @teardown: Teardown function of the step
>> 73 * @skip_onerr: Do not invoke the functions on error rollback
>> 74 * Will go away once the notifiers are gone
122 * @cant_stop: Bringup/teardown can't be stop 75 * @cant_stop: Bringup/teardown can't be stopped at this step
123 * @multi_instance: State has multiple ins <<
124 */ 76 */
125 struct cpuhp_step { 77 struct cpuhp_step {
126 const char *name; 78 const char *name;
127 union { 79 union {
128 int (*single)(unsi 80 int (*single)(unsigned int cpu);
129 int (*multi)(unsig 81 int (*multi)(unsigned int cpu,
130 struc 82 struct hlist_node *node);
131 } startup; 83 } startup;
132 union { 84 union {
133 int (*single)(unsi 85 int (*single)(unsigned int cpu);
134 int (*multi)(unsig 86 int (*multi)(unsigned int cpu,
135 struc 87 struct hlist_node *node);
136 } teardown; 88 } teardown;
137 /* private: */ <<
138 struct hlist_head list; 89 struct hlist_head list;
139 /* public: */ !! 90 bool skip_onerr;
140 bool cant_stop; 91 bool cant_stop;
141 bool multi_instance 92 bool multi_instance;
142 }; 93 };
143 94
144 static DEFINE_MUTEX(cpuhp_state_mutex); 95 static DEFINE_MUTEX(cpuhp_state_mutex);
145 static struct cpuhp_step cpuhp_hp_states[]; !! 96 static struct cpuhp_step cpuhp_bp_states[];
>> 97 static struct cpuhp_step cpuhp_ap_states[];
146 98
147 static struct cpuhp_step *cpuhp_get_step(enum !! 99 static bool cpuhp_is_ap_state(enum cpuhp_state state)
148 { 100 {
149 return cpuhp_hp_states + state; !! 101 /*
>> 102 * The extra check for CPUHP_TEARDOWN_CPU is only for documentation
>> 103 * purposes as that state is handled explicitly in cpu_down.
>> 104 */
>> 105 return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
150 } 106 }
151 107
152 static bool cpuhp_step_empty(bool bringup, str !! 108 static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
153 { 109 {
154 return bringup ? !step->startup.single !! 110 struct cpuhp_step *sp;
>> 111
>> 112 sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states;
>> 113 return sp + state;
155 } 114 }
156 115
157 /** 116 /**
158 * cpuhp_invoke_callback - Invoke the callback !! 117 * cpuhp_invoke_callback _ Invoke the callbacks for a given state
159 * @cpu: The cpu for which the callback 118 * @cpu: The cpu for which the callback should be invoked
160 * @state: The state to do callbacks for !! 119 * @step: The step in the state machine
161 * @bringup: True if the bringup callback s 120 * @bringup: True if the bringup callback should be invoked
162 * @node: For multi-instance, do a singl <<
163 * @lastp: For multi-instance rollback, r <<
164 * 121 *
165 * Called from cpu hotplug and from the state 122 * Called from cpu hotplug and from the state register machinery.
166 * <<
167 * Return: %0 on success or a negative errno c <<
168 */ 123 */
169 static int cpuhp_invoke_callback(unsigned int 124 static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
170 bool bringup, !! 125 bool bringup, struct hlist_node *node)
171 struct hlist_ <<
172 { 126 {
173 struct cpuhp_cpu_state *st = per_cpu_p 127 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
174 struct cpuhp_step *step = cpuhp_get_st 128 struct cpuhp_step *step = cpuhp_get_step(state);
175 int (*cbm)(unsigned int cpu, struct hl 129 int (*cbm)(unsigned int cpu, struct hlist_node *node);
176 int (*cb)(unsigned int cpu); 130 int (*cb)(unsigned int cpu);
177 int ret, cnt; 131 int ret, cnt;
178 132
179 if (st->fail == state) { <<
180 st->fail = CPUHP_INVALID; <<
181 return -EAGAIN; <<
182 } <<
183 <<
184 if (cpuhp_step_empty(bringup, step)) { <<
185 WARN_ON_ONCE(1); <<
186 return 0; <<
187 } <<
188 <<
189 if (!step->multi_instance) { 133 if (!step->multi_instance) {
190 WARN_ON_ONCE(lastp && *lastp); <<
191 cb = bringup ? step->startup.s 134 cb = bringup ? step->startup.single : step->teardown.single;
192 !! 135 if (!cb)
>> 136 return 0;
193 trace_cpuhp_enter(cpu, st->tar 137 trace_cpuhp_enter(cpu, st->target, state, cb);
194 ret = cb(cpu); 138 ret = cb(cpu);
195 trace_cpuhp_exit(cpu, st->stat 139 trace_cpuhp_exit(cpu, st->state, state, ret);
196 return ret; 140 return ret;
197 } 141 }
198 cbm = bringup ? step->startup.multi : 142 cbm = bringup ? step->startup.multi : step->teardown.multi;
>> 143 if (!cbm)
>> 144 return 0;
199 145
200 /* Single invocation for instance add/ 146 /* Single invocation for instance add/remove */
201 if (node) { 147 if (node) {
202 WARN_ON_ONCE(lastp && *lastp); <<
203 trace_cpuhp_multi_enter(cpu, s 148 trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
204 ret = cbm(cpu, node); 149 ret = cbm(cpu, node);
205 trace_cpuhp_exit(cpu, st->stat 150 trace_cpuhp_exit(cpu, st->state, state, ret);
206 return ret; 151 return ret;
207 } 152 }
208 153
209 /* State transition. Invoke on all ins 154 /* State transition. Invoke on all instances */
210 cnt = 0; 155 cnt = 0;
211 hlist_for_each(node, &step->list) { 156 hlist_for_each(node, &step->list) {
212 if (lastp && node == *lastp) <<
213 break; <<
214 <<
215 trace_cpuhp_multi_enter(cpu, s 157 trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
216 ret = cbm(cpu, node); 158 ret = cbm(cpu, node);
217 trace_cpuhp_exit(cpu, st->stat 159 trace_cpuhp_exit(cpu, st->state, state, ret);
218 if (ret) { !! 160 if (ret)
219 if (!lastp) !! 161 goto err;
220 goto err; <<
221 <<
222 *lastp = node; <<
223 return ret; <<
224 } <<
225 cnt++; 162 cnt++;
226 } 163 }
227 if (lastp) <<
228 *lastp = NULL; <<
229 return 0; 164 return 0;
230 err: 165 err:
231 /* Rollback the instances if one faile 166 /* Rollback the instances if one failed */
232 cbm = !bringup ? step->startup.multi : 167 cbm = !bringup ? step->startup.multi : step->teardown.multi;
233 if (!cbm) 168 if (!cbm)
234 return ret; 169 return ret;
235 170
236 hlist_for_each(node, &step->list) { 171 hlist_for_each(node, &step->list) {
237 if (!cnt--) 172 if (!cnt--)
238 break; 173 break;
239 !! 174 cbm(cpu, node);
240 trace_cpuhp_multi_enter(cpu, s <<
241 ret = cbm(cpu, node); <<
242 trace_cpuhp_exit(cpu, st->stat <<
243 /* <<
244 * Rollback must not fail, <<
245 */ <<
246 WARN_ON_ONCE(ret); <<
247 } 175 }
248 return ret; 176 return ret;
249 } 177 }
250 178
251 #ifdef CONFIG_SMP 179 #ifdef CONFIG_SMP
252 static bool cpuhp_is_ap_state(enum cpuhp_state <<
253 { <<
254 /* <<
255 * The extra check for CPUHP_TEARDOWN_ <<
256 * purposes as that state is handled e <<
257 */ <<
258 return state > CPUHP_BRINGUP_CPU && st <<
259 } <<
260 <<
261 static inline void wait_for_ap_thread(struct c <<
262 { <<
263 struct completion *done = bringup ? &s <<
264 wait_for_completion(done); <<
265 } <<
266 <<
267 static inline void complete_ap_thread(struct c <<
268 { <<
269 struct completion *done = bringup ? &s <<
270 complete(done); <<
271 } <<
272 <<
273 /* <<
274 * The former STARTING/DYING states, ran with <<
275 */ <<
276 static bool cpuhp_is_atomic_state(enum cpuhp_s <<
277 { <<
278 return CPUHP_AP_IDLE_DEAD <= state && <<
279 } <<
280 <<
281 /* Synchronization state management */ <<
282 enum cpuhp_sync_state { <<
283 SYNC_STATE_DEAD, <<
284 SYNC_STATE_KICKED, <<
285 SYNC_STATE_SHOULD_DIE, <<
286 SYNC_STATE_ALIVE, <<
287 SYNC_STATE_SHOULD_ONLINE, <<
288 SYNC_STATE_ONLINE, <<
289 }; <<
290 <<
291 #ifdef CONFIG_HOTPLUG_CORE_SYNC <<
292 /** <<
293 * cpuhp_ap_update_sync_state - Update synchro <<
294 * @state: The synchronization state to s <<
295 * <<
296 * No synchronization point. Just update of th <<
297 * a full barrier so that the AP changes are v <<
298 */ <<
299 static inline void cpuhp_ap_update_sync_state( <<
300 { <<
301 atomic_t *st = this_cpu_ptr(&cpuhp_sta <<
302 <<
303 (void)atomic_xchg(st, state); <<
304 } <<
305 <<
306 void __weak arch_cpuhp_sync_state_poll(void) { <<
307 <<
308 static bool cpuhp_wait_for_sync_state(unsigned <<
309 enum cpu <<
310 { <<
311 atomic_t *st = per_cpu_ptr(&cpuhp_stat <<
312 ktime_t now, end, start = ktime_get(); <<
313 int sync; <<
314 <<
315 end = start + 10ULL * NSEC_PER_SEC; <<
316 <<
317 sync = atomic_read(st); <<
318 while (1) { <<
319 if (sync == state) { <<
320 if (!atomic_try_cmpxch <<
321 continue; <<
322 return true; <<
323 } <<
324 <<
325 now = ktime_get(); <<
326 if (now > end) { <<
327 /* Timeout. Leave the <<
328 return false; <<
329 } else if (now - start < NSEC_ <<
330 /* Poll for one millis <<
331 arch_cpuhp_sync_state_ <<
332 } else { <<
333 usleep_range(USEC_PER_ <<
334 } <<
335 sync = atomic_read(st); <<
336 } <<
337 return true; <<
338 } <<
339 #else /* CONFIG_HOTPLUG_CORE_SYNC */ <<
340 static inline void cpuhp_ap_update_sync_state( <<
341 #endif /* !CONFIG_HOTPLUG_CORE_SYNC */ <<
342 <<
343 #ifdef CONFIG_HOTPLUG_CORE_SYNC_DEAD <<
344 /** <<
345 * cpuhp_ap_report_dead - Update synchronizati <<
346 * <<
347 * No synchronization point. Just update of th <<
348 */ <<
349 void cpuhp_ap_report_dead(void) <<
350 { <<
351 cpuhp_ap_update_sync_state(SYNC_STATE_ <<
352 } <<
353 <<
354 void __weak arch_cpuhp_cleanup_dead_cpu(unsign <<
355 <<
356 /* <<
357 * Late CPU shutdown synchronization point. Ca <<
358 * because the AP cannot issue complete() at t <<
359 */ <<
360 static void cpuhp_bp_sync_dead(unsigned int cp <<
361 { <<
362 atomic_t *st = per_cpu_ptr(&cpuhp_stat <<
363 int sync = atomic_read(st); <<
364 <<
365 do { <<
366 /* CPU can have reported dead <<
367 if (sync == SYNC_STATE_DEAD) <<
368 break; <<
369 } while (!atomic_try_cmpxchg(st, &sync <<
370 <<
371 if (cpuhp_wait_for_sync_state(cpu, SYN <<
372 /* CPU reached dead state. Inv <<
373 arch_cpuhp_cleanup_dead_cpu(cp <<
374 return; <<
375 } <<
376 <<
377 /* No further action possible. Emit me <<
378 pr_err("CPU%u failed to report dead st <<
379 } <<
380 #else /* CONFIG_HOTPLUG_CORE_SYNC_DEAD */ <<
381 static inline void cpuhp_bp_sync_dead(unsigned <<
382 #endif /* !CONFIG_HOTPLUG_CORE_SYNC_DEAD */ <<
383 <<
384 #ifdef CONFIG_HOTPLUG_CORE_SYNC_FULL <<
385 /** <<
386 * cpuhp_ap_sync_alive - Synchronize AP with t <<
387 * <<
388 * Updates the AP synchronization state to SYN <<
389 * for the BP to release it. <<
390 */ <<
391 void cpuhp_ap_sync_alive(void) <<
392 { <<
393 atomic_t *st = this_cpu_ptr(&cpuhp_sta <<
394 <<
395 cpuhp_ap_update_sync_state(SYNC_STATE_ <<
396 <<
397 /* Wait for the control CPU to release <<
398 while (atomic_read(st) != SYNC_STATE_S <<
399 cpu_relax(); <<
400 } <<
401 <<
402 static bool cpuhp_can_boot_ap(unsigned int cpu <<
403 { <<
404 atomic_t *st = per_cpu_ptr(&cpuhp_stat <<
405 int sync = atomic_read(st); <<
406 <<
407 again: <<
408 switch (sync) { <<
409 case SYNC_STATE_DEAD: <<
410 /* CPU is properly dead */ <<
411 break; <<
412 case SYNC_STATE_KICKED: <<
413 /* CPU did not come up in prev <<
414 break; <<
415 case SYNC_STATE_ALIVE: <<
416 /* CPU is stuck cpuhp_ap_sync_ <<
417 break; <<
418 default: <<
419 /* CPU failed to report online <<
420 return false; <<
421 } <<
422 <<
423 /* Prepare for booting */ <<
424 if (!atomic_try_cmpxchg(st, &sync, SYN <<
425 goto again; <<
426 <<
427 return true; <<
428 } <<
429 <<
430 void __weak arch_cpuhp_cleanup_kick_cpu(unsign <<
431 <<
432 /* <<
433 * Early CPU bringup synchronization point. Ca <<
434 * because the AP cannot issue complete() so e <<
435 */ <<
436 static int cpuhp_bp_sync_alive(unsigned int cp <<
437 { <<
438 int ret = 0; <<
439 <<
440 if (!IS_ENABLED(CONFIG_HOTPLUG_CORE_SY <<
441 return 0; <<
442 <<
443 if (!cpuhp_wait_for_sync_state(cpu, SY <<
444 pr_err("CPU%u failed to report <<
445 ret = -EIO; <<
446 } <<
447 <<
448 /* Let the architecture cleanup the ki <<
449 arch_cpuhp_cleanup_kick_cpu(cpu); <<
450 return ret; <<
451 } <<
452 #else /* CONFIG_HOTPLUG_CORE_SYNC_FULL */ <<
453 static inline int cpuhp_bp_sync_alive(unsigned <<
454 static inline bool cpuhp_can_boot_ap(unsigned <<
455 #endif /* !CONFIG_HOTPLUG_CORE_SYNC_FULL */ <<
456 <<
457 /* Serializes the updates to cpu_online_mask, 180 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
458 static DEFINE_MUTEX(cpu_add_remove_lock); 181 static DEFINE_MUTEX(cpu_add_remove_lock);
459 bool cpuhp_tasks_frozen; 182 bool cpuhp_tasks_frozen;
460 EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); 183 EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
461 184
462 /* 185 /*
463 * The following two APIs (cpu_maps_update_beg 186 * The following two APIs (cpu_maps_update_begin/done) must be used when
464 * attempting to serialize the updates to cpu_ 187 * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
465 */ 188 */
466 void cpu_maps_update_begin(void) 189 void cpu_maps_update_begin(void)
467 { 190 {
468 mutex_lock(&cpu_add_remove_lock); 191 mutex_lock(&cpu_add_remove_lock);
469 } 192 }
470 193
471 void cpu_maps_update_done(void) 194 void cpu_maps_update_done(void)
472 { 195 {
473 mutex_unlock(&cpu_add_remove_lock); 196 mutex_unlock(&cpu_add_remove_lock);
474 } 197 }
475 198
476 /* !! 199 /* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
477 * If set, cpu_up and cpu_down will return -EB <<
478 * Should always be manipulated under cpu_add_ 200 * Should always be manipulated under cpu_add_remove_lock
479 */ 201 */
480 static int cpu_hotplug_disabled; 202 static int cpu_hotplug_disabled;
481 203
482 #ifdef CONFIG_HOTPLUG_CPU 204 #ifdef CONFIG_HOTPLUG_CPU
483 205
484 DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); !! 206 static struct {
>> 207 struct task_struct *active_writer;
>> 208 /* wait queue to wake up the active_writer */
>> 209 wait_queue_head_t wq;
>> 210 /* verifies that no writer will get active while readers are active */
>> 211 struct mutex lock;
>> 212 /*
>> 213 * Also blocks the new readers during
>> 214 * an ongoing cpu hotplug operation.
>> 215 */
>> 216 atomic_t refcount;
>> 217
>> 218 #ifdef CONFIG_DEBUG_LOCK_ALLOC
>> 219 struct lockdep_map dep_map;
>> 220 #endif
>> 221 } cpu_hotplug = {
>> 222 .active_writer = NULL,
>> 223 .wq = __WAIT_QUEUE_HEAD_INITIALIZER(cpu_hotplug.wq),
>> 224 .lock = __MUTEX_INITIALIZER(cpu_hotplug.lock),
>> 225 #ifdef CONFIG_DEBUG_LOCK_ALLOC
>> 226 .dep_map = STATIC_LOCKDEP_MAP_INIT("cpu_hotplug.dep_map", &cpu_hotplug.dep_map),
>> 227 #endif
>> 228 };
485 229
486 static bool cpu_hotplug_offline_disabled __ro_ !! 230 /* Lockdep annotations for get/put_online_cpus() and cpu_hotplug_begin/end() */
>> 231 #define cpuhp_lock_acquire_read() lock_map_acquire_read(&cpu_hotplug.dep_map)
>> 232 #define cpuhp_lock_acquire_tryread() \
>> 233 lock_map_acquire_tryread(&cpu_hotplug.dep_map)
>> 234 #define cpuhp_lock_acquire() lock_map_acquire(&cpu_hotplug.dep_map)
>> 235 #define cpuhp_lock_release() lock_map_release(&cpu_hotplug.dep_map)
487 236
488 void cpus_read_lock(void) <<
489 { <<
490 percpu_down_read(&cpu_hotplug_lock); <<
491 } <<
492 EXPORT_SYMBOL_GPL(cpus_read_lock); <<
493 237
494 int cpus_read_trylock(void) !! 238 void get_online_cpus(void)
495 { 239 {
496 return percpu_down_read_trylock(&cpu_h !! 240 might_sleep();
>> 241 if (cpu_hotplug.active_writer == current)
>> 242 return;
>> 243 cpuhp_lock_acquire_read();
>> 244 mutex_lock(&cpu_hotplug.lock);
>> 245 atomic_inc(&cpu_hotplug.refcount);
>> 246 mutex_unlock(&cpu_hotplug.lock);
497 } 247 }
498 EXPORT_SYMBOL_GPL(cpus_read_trylock); !! 248 EXPORT_SYMBOL_GPL(get_online_cpus);
499 249
500 void cpus_read_unlock(void) !! 250 void put_online_cpus(void)
501 { 251 {
502 percpu_up_read(&cpu_hotplug_lock); !! 252 int refcount;
503 } <<
504 EXPORT_SYMBOL_GPL(cpus_read_unlock); <<
505 253
506 void cpus_write_lock(void) !! 254 if (cpu_hotplug.active_writer == current)
507 { !! 255 return;
508 percpu_down_write(&cpu_hotplug_lock); <<
509 } <<
510 256
511 void cpus_write_unlock(void) !! 257 refcount = atomic_dec_return(&cpu_hotplug.refcount);
512 { !! 258 if (WARN_ON(refcount < 0)) /* try to fix things up */
513 percpu_up_write(&cpu_hotplug_lock); !! 259 atomic_inc(&cpu_hotplug.refcount);
514 } <<
515 260
516 void lockdep_assert_cpus_held(void) !! 261 if (refcount <= 0 && waitqueue_active(&cpu_hotplug.wq))
517 { !! 262 wake_up(&cpu_hotplug.wq);
518 /* <<
519 * We can't have hotplug operations be <<
520 * and some init codepaths will knowin <<
521 * This is all valid, so mute lockdep <<
522 * unheld locks. <<
523 */ <<
524 if (system_state < SYSTEM_RUNNING) <<
525 return; <<
526 263
527 percpu_rwsem_assert_held(&cpu_hotplug_ !! 264 cpuhp_lock_release();
528 } <<
529 265
530 #ifdef CONFIG_LOCKDEP <<
531 int lockdep_is_cpus_held(void) <<
532 { <<
533 return percpu_rwsem_is_held(&cpu_hotpl <<
534 } 266 }
535 #endif !! 267 EXPORT_SYMBOL_GPL(put_online_cpus);
536 268
537 static void lockdep_acquire_cpus_lock(void) !! 269 /*
>> 270 * This ensures that the hotplug operation can begin only when the
>> 271 * refcount goes to zero.
>> 272 *
>> 273 * Note that during a cpu-hotplug operation, the new readers, if any,
>> 274 * will be blocked by the cpu_hotplug.lock
>> 275 *
>> 276 * Since cpu_hotplug_begin() is always called after invoking
>> 277 * cpu_maps_update_begin(), we can be sure that only one writer is active.
>> 278 *
>> 279 * Note that theoretically, there is a possibility of a livelock:
>> 280 * - Refcount goes to zero, last reader wakes up the sleeping
>> 281 * writer.
>> 282 * - Last reader unlocks the cpu_hotplug.lock.
>> 283 * - A new reader arrives at this moment, bumps up the refcount.
>> 284 * - The writer acquires the cpu_hotplug.lock finds the refcount
>> 285 * non zero and goes to sleep again.
>> 286 *
>> 287 * However, this is very difficult to achieve in practice since
>> 288 * get_online_cpus() not an api which is called all that often.
>> 289 *
>> 290 */
>> 291 void cpu_hotplug_begin(void)
538 { 292 {
539 rwsem_acquire(&cpu_hotplug_lock.dep_ma !! 293 DEFINE_WAIT(wait);
540 } <<
541 294
542 static void lockdep_release_cpus_lock(void) !! 295 cpu_hotplug.active_writer = current;
543 { !! 296 cpuhp_lock_acquire();
544 rwsem_release(&cpu_hotplug_lock.dep_ma !! 297
>> 298 for (;;) {
>> 299 mutex_lock(&cpu_hotplug.lock);
>> 300 prepare_to_wait(&cpu_hotplug.wq, &wait, TASK_UNINTERRUPTIBLE);
>> 301 if (likely(!atomic_read(&cpu_hotplug.refcount)))
>> 302 break;
>> 303 mutex_unlock(&cpu_hotplug.lock);
>> 304 schedule();
>> 305 }
>> 306 finish_wait(&cpu_hotplug.wq, &wait);
545 } 307 }
546 308
547 /* Declare CPU offlining not supported */ !! 309 void cpu_hotplug_done(void)
548 void cpu_hotplug_disable_offlining(void) <<
549 { 310 {
550 cpu_maps_update_begin(); !! 311 cpu_hotplug.active_writer = NULL;
551 cpu_hotplug_offline_disabled = true; !! 312 mutex_unlock(&cpu_hotplug.lock);
552 cpu_maps_update_done(); !! 313 cpuhp_lock_release();
553 } 314 }
554 315
555 /* 316 /*
556 * Wait for currently running CPU hotplug oper 317 * Wait for currently running CPU hotplug operations to complete (if any) and
557 * disable future CPU hotplug (from sysfs). Th 318 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
558 * the 'cpu_hotplug_disabled' flag. The same l 319 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
559 * hotplug path before performing hotplug oper 320 * hotplug path before performing hotplug operations. So acquiring that lock
560 * guarantees mutual exclusion from any curren 321 * guarantees mutual exclusion from any currently running hotplug operations.
561 */ 322 */
562 void cpu_hotplug_disable(void) 323 void cpu_hotplug_disable(void)
563 { 324 {
564 cpu_maps_update_begin(); 325 cpu_maps_update_begin();
565 cpu_hotplug_disabled++; 326 cpu_hotplug_disabled++;
566 cpu_maps_update_done(); 327 cpu_maps_update_done();
567 } 328 }
568 EXPORT_SYMBOL_GPL(cpu_hotplug_disable); 329 EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
569 330
570 static void __cpu_hotplug_enable(void) 331 static void __cpu_hotplug_enable(void)
571 { 332 {
572 if (WARN_ONCE(!cpu_hotplug_disabled, " 333 if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n"))
573 return; 334 return;
574 cpu_hotplug_disabled--; 335 cpu_hotplug_disabled--;
575 } 336 }
576 337
577 void cpu_hotplug_enable(void) 338 void cpu_hotplug_enable(void)
578 { 339 {
579 cpu_maps_update_begin(); 340 cpu_maps_update_begin();
580 __cpu_hotplug_enable(); 341 __cpu_hotplug_enable();
581 cpu_maps_update_done(); 342 cpu_maps_update_done();
582 } 343 }
583 EXPORT_SYMBOL_GPL(cpu_hotplug_enable); 344 EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
584 <<
585 #else <<
586 <<
587 static void lockdep_acquire_cpus_lock(void) <<
588 { <<
589 } <<
590 <<
591 static void lockdep_release_cpus_lock(void) <<
592 { <<
593 } <<
594 <<
595 #endif /* CONFIG_HOTPLUG_CPU */ 345 #endif /* CONFIG_HOTPLUG_CPU */
596 346
597 /* !! 347 /* Notifier wrappers for transitioning to state machine */
598 * Architectures that need SMT-specific errata <<
599 * should override this. <<
600 */ <<
601 void __weak arch_smt_update(void) { } <<
602 <<
603 #ifdef CONFIG_HOTPLUG_SMT <<
604 348
605 enum cpuhp_smt_control cpu_smt_control __read_ !! 349 static int bringup_wait_for_ap(unsigned int cpu)
606 static unsigned int cpu_smt_max_threads __ro_a <<
607 unsigned int cpu_smt_num_threads __read_mostly <<
608 <<
609 void __init cpu_smt_disable(bool force) <<
610 { <<
611 if (!cpu_smt_possible()) <<
612 return; <<
613 <<
614 if (force) { <<
615 pr_info("SMT: Force disabled\n <<
616 cpu_smt_control = CPU_SMT_FORC <<
617 } else { <<
618 pr_info("SMT: disabled\n"); <<
619 cpu_smt_control = CPU_SMT_DISA <<
620 } <<
621 cpu_smt_num_threads = 1; <<
622 } <<
623 <<
624 /* <<
625 * The decision whether SMT is supported can o <<
626 * CPU identification. Called from architectur <<
627 */ <<
628 void __init cpu_smt_set_num_threads(unsigned i <<
629 unsigned i <<
630 { <<
631 WARN_ON(!num_threads || (num_threads > <<
632 <<
633 if (max_threads == 1) <<
634 cpu_smt_control = CPU_SMT_NOT_ <<
635 <<
636 cpu_smt_max_threads = max_threads; <<
637 <<
638 /* <<
639 * If SMT has been disabled via the ke <<
640 * not supported, set cpu_smt_num_thre <<
641 * If enabled, take the architecture r <<
642 * to bring up into account. <<
643 */ <<
644 if (cpu_smt_control != CPU_SMT_ENABLED <<
645 cpu_smt_num_threads = 1; <<
646 else if (num_threads < cpu_smt_num_thr <<
647 cpu_smt_num_threads = num_thre <<
648 } <<
649 <<
650 static int __init smt_cmdline_disable(char *st <<
651 { <<
652 cpu_smt_disable(str && !strcmp(str, "f <<
653 return 0; <<
654 } <<
655 early_param("nosmt", smt_cmdline_disable); <<
656 <<
657 /* <<
658 * For Archicture supporting partial SMT state <<
659 * Otherwise this has already been checked thr <<
660 * setting the SMT level. <<
661 */ <<
662 static inline bool cpu_smt_thread_allowed(unsi <<
663 { <<
664 #ifdef CONFIG_SMT_NUM_THREADS_DYNAMIC <<
665 return topology_smt_thread_allowed(cpu <<
666 #else <<
667 return true; <<
668 #endif <<
669 } <<
670 <<
671 static inline bool cpu_bootable(unsigned int c <<
672 { <<
673 if (cpu_smt_control == CPU_SMT_ENABLED <<
674 return true; <<
675 <<
676 /* All CPUs are bootable if controls a <<
677 if (cpu_smt_control == CPU_SMT_NOT_IMP <<
678 return true; <<
679 <<
680 /* All CPUs are bootable if CPU is not <<
681 if (cpu_smt_control == CPU_SMT_NOT_SUP <<
682 return true; <<
683 <<
684 if (topology_is_primary_thread(cpu)) <<
685 return true; <<
686 <<
687 /* <<
688 * On x86 it's required to boot all lo <<
689 * that the init code can get a chance <<
690 * CPU. Otherwise, a broadcasted MCE o <<
691 * core will shutdown the machine. <<
692 */ <<
693 return !cpumask_test_cpu(cpu, &cpus_bo <<
694 } <<
695 <<
696 /* Returns true if SMT is supported and not fo <<
697 bool cpu_smt_possible(void) <<
698 { <<
699 return cpu_smt_control != CPU_SMT_FORC <<
700 cpu_smt_control != CPU_SMT_NOT <<
701 } <<
702 EXPORT_SYMBOL_GPL(cpu_smt_possible); <<
703 <<
704 #else <<
705 static inline bool cpu_bootable(unsigned int c <<
706 #endif <<
707 <<
708 static inline enum cpuhp_state <<
709 cpuhp_set_state(int cpu, struct cpuhp_cpu_stat <<
710 { <<
711 enum cpuhp_state prev_state = st->stat <<
712 bool bringup = st->state < target; <<
713 <<
714 st->rollback = false; <<
715 st->last = NULL; <<
716 <<
717 st->target = target; <<
718 st->single = false; <<
719 st->bringup = bringup; <<
720 if (cpu_dying(cpu) != !bringup) <<
721 set_cpu_dying(cpu, !bringup); <<
722 <<
723 return prev_state; <<
724 } <<
725 <<
726 static inline void <<
727 cpuhp_reset_state(int cpu, struct cpuhp_cpu_st <<
728 enum cpuhp_state prev_state) <<
729 { <<
730 bool bringup = !st->bringup; <<
731 <<
732 st->target = prev_state; <<
733 <<
734 /* <<
735 * Already rolling back. No need inver <<
736 * the current state. <<
737 */ <<
738 if (st->rollback) <<
739 return; <<
740 <<
741 st->rollback = true; <<
742 <<
743 /* <<
744 * If we have st->last we need to undo <<
745 * state first. Otherwise start undo a <<
746 */ <<
747 if (!st->last) { <<
748 if (st->bringup) <<
749 st->state--; <<
750 else <<
751 st->state++; <<
752 } <<
753 <<
754 st->bringup = bringup; <<
755 if (cpu_dying(cpu) != !bringup) <<
756 set_cpu_dying(cpu, !bringup); <<
757 } <<
758 <<
759 /* Regular hotplug invocation of the AP hotplu <<
760 static void __cpuhp_kick_ap(struct cpuhp_cpu_s <<
761 { <<
762 if (!st->single && st->state == st->ta <<
763 return; <<
764 <<
765 st->result = 0; <<
766 /* <<
767 * Make sure the above stores are visi <<
768 * true. Paired with the mb() above in <<
769 */ <<
770 smp_mb(); <<
771 st->should_run = true; <<
772 wake_up_process(st->thread); <<
773 wait_for_ap_thread(st, st->bringup); <<
774 } <<
775 <<
776 static int cpuhp_kick_ap(int cpu, struct cpuhp <<
777 enum cpuhp_state targ <<
778 { <<
779 enum cpuhp_state prev_state; <<
780 int ret; <<
781 <<
782 prev_state = cpuhp_set_state(cpu, st, <<
783 __cpuhp_kick_ap(st); <<
784 if ((ret = st->result)) { <<
785 cpuhp_reset_state(cpu, st, pre <<
786 __cpuhp_kick_ap(st); <<
787 } <<
788 <<
789 return ret; <<
790 } <<
791 <<
792 static int bringup_wait_for_ap_online(unsigned <<
793 { 350 {
794 struct cpuhp_cpu_state *st = per_cpu_p 351 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
795 352
796 /* Wait for the CPU to reach CPUHP_AP_ !! 353 wait_for_completion(&st->done);
797 wait_for_ap_thread(st, true); !! 354 return st->result;
798 if (WARN_ON_ONCE((!cpu_online(cpu)))) <<
799 return -ECANCELED; <<
800 <<
801 /* Unpark the hotplug thread of the ta <<
802 kthread_unpark(st->thread); <<
803 <<
804 /* <<
805 * SMT soft disabling on X86 requires <<
806 * BIOS 'wait for SIPI' state in order <<
807 * CPU marked itself as booted_once in <<
808 * cpu_bootable() check will now retur <<
809 * primary sibling. <<
810 */ <<
811 if (!cpu_bootable(cpu)) <<
812 return -ECANCELED; <<
813 return 0; <<
814 } <<
815 <<
816 #ifdef CONFIG_HOTPLUG_SPLIT_STARTUP <<
817 static int cpuhp_kick_ap_alive(unsigned int cp <<
818 { <<
819 if (!cpuhp_can_boot_ap(cpu)) <<
820 return -EAGAIN; <<
821 <<
822 return arch_cpuhp_kick_ap_alive(cpu, i <<
823 } 355 }
824 356
825 static int cpuhp_bringup_ap(unsigned int cpu) <<
826 { <<
827 struct cpuhp_cpu_state *st = per_cpu_p <<
828 int ret; <<
829 <<
830 /* <<
831 * Some architectures have to walk the <<
832 * setup the vector space for the cpu <<
833 * Prevent irq alloc/free across the b <<
834 */ <<
835 irq_lock_sparse(); <<
836 <<
837 ret = cpuhp_bp_sync_alive(cpu); <<
838 if (ret) <<
839 goto out_unlock; <<
840 <<
841 ret = bringup_wait_for_ap_online(cpu); <<
842 if (ret) <<
843 goto out_unlock; <<
844 <<
845 irq_unlock_sparse(); <<
846 <<
847 if (st->target <= CPUHP_AP_ONLINE_IDLE <<
848 return 0; <<
849 <<
850 return cpuhp_kick_ap(cpu, st, st->targ <<
851 <<
852 out_unlock: <<
853 irq_unlock_sparse(); <<
854 return ret; <<
855 } <<
856 #else <<
857 static int bringup_cpu(unsigned int cpu) 357 static int bringup_cpu(unsigned int cpu)
858 { 358 {
859 struct cpuhp_cpu_state *st = per_cpu_p <<
860 struct task_struct *idle = idle_thread 359 struct task_struct *idle = idle_thread_get(cpu);
861 int ret; 360 int ret;
862 361
863 if (!cpuhp_can_boot_ap(cpu)) <<
864 return -EAGAIN; <<
865 <<
866 /* 362 /*
867 * Some architectures have to walk the 363 * Some architectures have to walk the irq descriptors to
868 * setup the vector space for the cpu 364 * setup the vector space for the cpu which comes online.
869 * !! 365 * Prevent irq alloc/free across the bringup.
870 * Prevent irq alloc/free across the b <<
871 * sparse irq lock. Hold it until the <<
872 * startup in cpuhp_online_idle() whic <<
873 * intermediate synchronization points <<
874 */ 366 */
875 irq_lock_sparse(); 367 irq_lock_sparse();
876 368
>> 369 /* Arch-specific enabling code. */
877 ret = __cpu_up(cpu, idle); 370 ret = __cpu_up(cpu, idle);
878 if (ret) <<
879 goto out_unlock; <<
880 <<
881 ret = cpuhp_bp_sync_alive(cpu); <<
882 if (ret) <<
883 goto out_unlock; <<
884 <<
885 ret = bringup_wait_for_ap_online(cpu); <<
886 if (ret) <<
887 goto out_unlock; <<
888 <<
889 irq_unlock_sparse(); <<
890 <<
891 if (st->target <= CPUHP_AP_ONLINE_IDLE <<
892 return 0; <<
893 <<
894 return cpuhp_kick_ap(cpu, st, st->targ <<
895 <<
896 out_unlock: <<
897 irq_unlock_sparse(); 371 irq_unlock_sparse();
>> 372 if (ret)
>> 373 return ret;
>> 374 ret = bringup_wait_for_ap(cpu);
>> 375 BUG_ON(!cpu_online(cpu));
898 return ret; 376 return ret;
899 } 377 }
900 #endif <<
901 <<
902 static int finish_cpu(unsigned int cpu) <<
903 { <<
904 struct task_struct *idle = idle_thread <<
905 struct mm_struct *mm = idle->active_mm <<
906 <<
907 /* <<
908 * idle_task_exit() will have switched <<
909 * clean up any remaining active_mm st <<
910 */ <<
911 if (mm != &init_mm) <<
912 idle->active_mm = &init_mm; <<
913 mmdrop_lazy_tlb(mm); <<
914 return 0; <<
915 } <<
916 378
917 /* 379 /*
918 * Hotplug state machine related functions 380 * Hotplug state machine related functions
919 */ 381 */
>> 382 static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st)
>> 383 {
>> 384 for (st->state++; st->state < st->target; st->state++) {
>> 385 struct cpuhp_step *step = cpuhp_get_step(st->state);
920 386
921 /* !! 387 if (!step->skip_onerr)
922 * Get the next state to run. Empty ones will !! 388 cpuhp_invoke_callback(cpu, st->state, true, NULL);
923 * state must be run. !! 389 }
924 * <<
925 * st->state will be modified ahead of time, t <<
926 * has already ran. <<
927 */ <<
928 static bool cpuhp_next_state(bool bringup, <<
929 enum cpuhp_state <<
930 struct cpuhp_cpu_ <<
931 enum cpuhp_state <<
932 { <<
933 do { <<
934 if (bringup) { <<
935 if (st->state >= targe <<
936 return false; <<
937 <<
938 *state_to_run = ++st-> <<
939 } else { <<
940 if (st->state <= targe <<
941 return false; <<
942 <<
943 *state_to_run = st->st <<
944 } <<
945 <<
946 if (!cpuhp_step_empty(bringup, <<
947 break; <<
948 } while (true); <<
949 <<
950 return true; <<
951 } 390 }
952 391
953 static int __cpuhp_invoke_callback_range(bool !! 392 static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
954 unsig !! 393 enum cpuhp_state target)
955 struc <<
956 enum <<
957 bool <<
958 { 394 {
959 enum cpuhp_state state; !! 395 enum cpuhp_state prev_state = st->state;
960 int ret = 0; 396 int ret = 0;
961 397
962 while (cpuhp_next_state(bringup, &stat !! 398 for (; st->state > target; st->state--) {
963 int err; !! 399 ret = cpuhp_invoke_callback(cpu, st->state, false, NULL);
964 !! 400 if (ret) {
965 err = cpuhp_invoke_callback(cp !! 401 st->target = prev_state;
966 if (!err) !! 402 undo_cpu_down(cpu, st);
967 continue; <<
968 <<
969 if (nofail) { <<
970 pr_warn("CPU %u %s sta <<
971 cpu, bringup ? <<
972 cpuhp_get_step <<
973 st->state, err <<
974 ret = -1; <<
975 } else { <<
976 ret = err; <<
977 break; 403 break;
978 } 404 }
979 } 405 }
980 <<
981 return ret; 406 return ret;
982 } 407 }
983 408
984 static inline int cpuhp_invoke_callback_range( !! 409 static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st)
985 <<
986 <<
987 <<
988 { 410 {
989 return __cpuhp_invoke_callback_range(b !! 411 for (st->state--; st->state > st->target; st->state--) {
990 } !! 412 struct cpuhp_step *step = cpuhp_get_step(st->state);
991 <<
992 static inline void cpuhp_invoke_callback_range <<
993 <<
994 <<
995 <<
996 { <<
997 __cpuhp_invoke_callback_range(bringup, <<
998 } <<
999 413
1000 static inline bool can_rollback_cpu(struct cp !! 414 if (!step->skip_onerr)
1001 { !! 415 cpuhp_invoke_callback(cpu, st->state, false, NULL);
1002 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) !! 416 }
1003 return true; <<
1004 /* <<
1005 * When CPU hotplug is disabled, then <<
1006 * possible because takedown_cpu() an <<
1007 * subsystem specific mechanisms are <<
1008 * which would be completely unplugge <<
1009 * in the current state. <<
1010 */ <<
1011 return st->state <= CPUHP_BRINGUP_CPU <<
1012 } 417 }
1013 418
1014 static int cpuhp_up_callbacks(unsigned int cp 419 static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
1015 enum cpuhp_stat 420 enum cpuhp_state target)
1016 { 421 {
1017 enum cpuhp_state prev_state = st->sta 422 enum cpuhp_state prev_state = st->state;
1018 int ret = 0; 423 int ret = 0;
1019 424
1020 ret = cpuhp_invoke_callback_range(tru !! 425 while (st->state < target) {
1021 if (ret) { !! 426 st->state++;
1022 pr_debug("CPU UP failed (%d) !! 427 ret = cpuhp_invoke_callback(cpu, st->state, true, NULL);
1023 ret, cpu, cpuhp_get_ !! 428 if (ret) {
1024 st->state); !! 429 st->target = prev_state;
1025 !! 430 undo_cpu_up(cpu, st);
1026 cpuhp_reset_state(cpu, st, pr !! 431 break;
1027 if (can_rollback_cpu(st)) !! 432 }
1028 WARN_ON(cpuhp_invoke_ <<
1029 <<
1030 } 433 }
1031 return ret; 434 return ret;
1032 } 435 }
1033 436
1034 /* 437 /*
1035 * The cpu hotplug threads manage the bringup 438 * The cpu hotplug threads manage the bringup and teardown of the cpus
1036 */ 439 */
>> 440 static void cpuhp_create(unsigned int cpu)
>> 441 {
>> 442 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
>> 443
>> 444 init_completion(&st->done);
>> 445 }
>> 446
1037 static int cpuhp_should_run(unsigned int cpu) 447 static int cpuhp_should_run(unsigned int cpu)
1038 { 448 {
1039 struct cpuhp_cpu_state *st = this_cpu 449 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1040 450
1041 return st->should_run; 451 return st->should_run;
1042 } 452 }
1043 453
>> 454 /* Execute the teardown callbacks. Used to be CPU_DOWN_PREPARE */
>> 455 static int cpuhp_ap_offline(unsigned int cpu, struct cpuhp_cpu_state *st)
>> 456 {
>> 457 enum cpuhp_state target = max((int)st->target, CPUHP_TEARDOWN_CPU);
>> 458
>> 459 return cpuhp_down_callbacks(cpu, st, target);
>> 460 }
>> 461
>> 462 /* Execute the online startup callbacks. Used to be CPU_ONLINE */
>> 463 static int cpuhp_ap_online(unsigned int cpu, struct cpuhp_cpu_state *st)
>> 464 {
>> 465 return cpuhp_up_callbacks(cpu, st, st->target);
>> 466 }
>> 467
1044 /* 468 /*
1045 * Execute teardown/startup callbacks on the 469 * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
1046 * callbacks when a state gets [un]installed 470 * callbacks when a state gets [un]installed at runtime.
1047 * <<
1048 * Each invocation of this function by the sm <<
1049 * state callback. <<
1050 * <<
1051 * It has 3 modes of operation: <<
1052 * - single: runs st->cb_state <<
1053 * - up: runs ++st->state, while st->sta <<
1054 * - down: runs st->state--, while st->sta <<
1055 * <<
1056 * When complete or on error, should_run is c <<
1057 */ 471 */
1058 static void cpuhp_thread_fun(unsigned int cpu 472 static void cpuhp_thread_fun(unsigned int cpu)
1059 { 473 {
1060 struct cpuhp_cpu_state *st = this_cpu 474 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1061 bool bringup = st->bringup; !! 475 int ret = 0;
1062 enum cpuhp_state state; <<
1063 <<
1064 if (WARN_ON_ONCE(!st->should_run)) <<
1065 return; <<
1066 476
1067 /* 477 /*
1068 * ACQUIRE for the cpuhp_should_run() !! 478 * Paired with the mb() in cpuhp_kick_ap_work and
1069 * that if we see ->should_run we als !! 479 * cpuhp_invoke_ap_callback, so the work set is consistent visible.
1070 */ 480 */
1071 smp_mb(); 481 smp_mb();
>> 482 if (!st->should_run)
>> 483 return;
1072 484
1073 /* !! 485 st->should_run = false;
1074 * The BP holds the hotplug lock, but <<
1075 * ensure that anybody asserting the <<
1076 * it so. <<
1077 */ <<
1078 lockdep_acquire_cpus_lock(); <<
1079 cpuhp_lock_acquire(bringup); <<
1080 486
>> 487 /* Single callback invocation for [un]install ? */
1081 if (st->single) { 488 if (st->single) {
1082 state = st->cb_state; !! 489 if (st->cb_state < CPUHP_AP_ONLINE) {
1083 st->should_run = false; !! 490 local_irq_disable();
1084 } else { !! 491 ret = cpuhp_invoke_callback(cpu, st->cb_state,
1085 st->should_run = cpuhp_next_s !! 492 st->bringup, st->node);
1086 if (!st->should_run) !! 493 local_irq_enable();
1087 goto end; !! 494 } else {
1088 } !! 495 ret = cpuhp_invoke_callback(cpu, st->cb_state,
1089 !! 496 st->bringup, st->node);
1090 WARN_ON_ONCE(!cpuhp_is_ap_state(state !! 497 }
1091 !! 498 } else if (st->rollback) {
1092 if (cpuhp_is_atomic_state(state)) { !! 499 BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
1093 local_irq_disable(); <<
1094 st->result = cpuhp_invoke_cal <<
1095 local_irq_enable(); <<
1096 500
1097 /* !! 501 undo_cpu_down(cpu, st);
1098 * STARTING/DYING must not fa !! 502 st->rollback = false;
1099 */ <<
1100 WARN_ON_ONCE(st->result); <<
1101 } else { 503 } else {
1102 st->result = cpuhp_invoke_cal !! 504 /* Cannot happen .... */
1103 } !! 505 BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE);
1104 506
1105 if (st->result) { !! 507 /* Regular hotplug work */
1106 /* !! 508 if (st->state < st->target)
1107 * If we fail on a rollback, !! 509 ret = cpuhp_ap_online(cpu, st);
1108 * paddle, no way forward, no !! 510 else if (st->state > st->target)
1109 * playing. !! 511 ret = cpuhp_ap_offline(cpu, st);
1110 */ <<
1111 WARN_ON_ONCE(st->rollback); <<
1112 st->should_run = false; <<
1113 } 512 }
1114 !! 513 st->result = ret;
1115 end: !! 514 complete(&st->done);
1116 cpuhp_lock_release(bringup); <<
1117 lockdep_release_cpus_lock(); <<
1118 <<
1119 if (!st->should_run) <<
1120 complete_ap_thread(st, bringu <<
1121 } 515 }
1122 516
1123 /* Invoke a single callback on a remote cpu * 517 /* Invoke a single callback on a remote cpu */
1124 static int 518 static int
1125 cpuhp_invoke_ap_callback(int cpu, enum cpuhp_ 519 cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup,
1126 struct hlist_node *n 520 struct hlist_node *node)
1127 { 521 {
1128 struct cpuhp_cpu_state *st = per_cpu_ 522 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1129 int ret; <<
1130 523
1131 if (!cpu_online(cpu)) 524 if (!cpu_online(cpu))
1132 return 0; 525 return 0;
1133 526
1134 cpuhp_lock_acquire(false); <<
1135 cpuhp_lock_release(false); <<
1136 <<
1137 cpuhp_lock_acquire(true); <<
1138 cpuhp_lock_release(true); <<
1139 <<
1140 /* 527 /*
1141 * If we are up and running, use the 528 * If we are up and running, use the hotplug thread. For early calls
1142 * we invoke the thread function dire 529 * we invoke the thread function directly.
1143 */ 530 */
1144 if (!st->thread) 531 if (!st->thread)
1145 return cpuhp_invoke_callback( !! 532 return cpuhp_invoke_callback(cpu, state, bringup, node);
1146 533
1147 st->rollback = false; <<
1148 st->last = NULL; <<
1149 <<
1150 st->node = node; <<
1151 st->bringup = bringup; <<
1152 st->cb_state = state; 534 st->cb_state = state;
1153 st->single = true; 535 st->single = true;
1154 !! 536 st->bringup = bringup;
1155 __cpuhp_kick_ap(st); !! 537 st->node = node;
1156 538
1157 /* 539 /*
1158 * If we failed and did a partial, do !! 540 * Make sure the above stores are visible before should_run becomes
>> 541 * true. Paired with the mb() above in cpuhp_thread_fun()
1159 */ 542 */
1160 if ((ret = st->result) && st->last) { !! 543 smp_mb();
1161 st->rollback = true; !! 544 st->should_run = true;
1162 st->bringup = !bringup; !! 545 wake_up_process(st->thread);
1163 !! 546 wait_for_completion(&st->done);
1164 __cpuhp_kick_ap(st); !! 547 return st->result;
1165 } !! 548 }
1166 549
>> 550 /* Regular hotplug invocation of the AP hotplug thread */
>> 551 static void __cpuhp_kick_ap_work(struct cpuhp_cpu_state *st)
>> 552 {
>> 553 st->result = 0;
>> 554 st->single = false;
1167 /* 555 /*
1168 * Clean up the leftovers so the next !! 556 * Make sure the above stores are visible before should_run becomes
1169 * data. !! 557 * true. Paired with the mb() above in cpuhp_thread_fun()
1170 */ 558 */
1171 st->node = st->last = NULL; !! 559 smp_mb();
1172 return ret; !! 560 st->should_run = true;
>> 561 wake_up_process(st->thread);
1173 } 562 }
1174 563
1175 static int cpuhp_kick_ap_work(unsigned int cp 564 static int cpuhp_kick_ap_work(unsigned int cpu)
1176 { 565 {
1177 struct cpuhp_cpu_state *st = per_cpu_ 566 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1178 enum cpuhp_state prev_state = st->sta !! 567 enum cpuhp_state state = st->state;
1179 int ret; <<
1180 <<
1181 cpuhp_lock_acquire(false); <<
1182 cpuhp_lock_release(false); <<
1183 <<
1184 cpuhp_lock_acquire(true); <<
1185 cpuhp_lock_release(true); <<
1186 568
1187 trace_cpuhp_enter(cpu, st->target, pr !! 569 trace_cpuhp_enter(cpu, st->target, state, cpuhp_kick_ap_work);
1188 ret = cpuhp_kick_ap(cpu, st, st->targ !! 570 __cpuhp_kick_ap_work(st);
1189 trace_cpuhp_exit(cpu, st->state, prev !! 571 wait_for_completion(&st->done);
1190 !! 572 trace_cpuhp_exit(cpu, st->state, state, st->result);
1191 return ret; !! 573 return st->result;
1192 } 574 }
1193 575
1194 static struct smp_hotplug_thread cpuhp_thread 576 static struct smp_hotplug_thread cpuhp_threads = {
1195 .store = &cpuhp_stat 577 .store = &cpuhp_state.thread,
>> 578 .create = &cpuhp_create,
1196 .thread_should_run = cpuhp_shoul 579 .thread_should_run = cpuhp_should_run,
1197 .thread_fn = cpuhp_threa 580 .thread_fn = cpuhp_thread_fun,
1198 .thread_comm = "cpuhp/%u", 581 .thread_comm = "cpuhp/%u",
1199 .selfparking = true, 582 .selfparking = true,
1200 }; 583 };
1201 584
1202 static __init void cpuhp_init_state(void) <<
1203 { <<
1204 struct cpuhp_cpu_state *st; <<
1205 int cpu; <<
1206 <<
1207 for_each_possible_cpu(cpu) { <<
1208 st = per_cpu_ptr(&cpuhp_state <<
1209 init_completion(&st->done_up) <<
1210 init_completion(&st->done_dow <<
1211 } <<
1212 } <<
1213 <<
1214 void __init cpuhp_threads_init(void) 585 void __init cpuhp_threads_init(void)
1215 { 586 {
1216 cpuhp_init_state(); <<
1217 BUG_ON(smpboot_register_percpu_thread 587 BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads));
1218 kthread_unpark(this_cpu_read(cpuhp_st 588 kthread_unpark(this_cpu_read(cpuhp_state.thread));
1219 } 589 }
1220 590
1221 #ifdef CONFIG_HOTPLUG_CPU 591 #ifdef CONFIG_HOTPLUG_CPU
1222 #ifndef arch_clear_mm_cpumask_cpu <<
1223 #define arch_clear_mm_cpumask_cpu(cpu, mm) cp <<
1224 #endif <<
1225 <<
1226 /** 592 /**
1227 * clear_tasks_mm_cpumask - Safely clear task 593 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
1228 * @cpu: a CPU id 594 * @cpu: a CPU id
1229 * 595 *
1230 * This function walks all processes, finds a 596 * This function walks all processes, finds a valid mm struct for each one and
1231 * then clears a corresponding bit in mm's cp 597 * then clears a corresponding bit in mm's cpumask. While this all sounds
1232 * trivial, there are various non-obvious cor 598 * trivial, there are various non-obvious corner cases, which this function
1233 * tries to solve in a safe manner. 599 * tries to solve in a safe manner.
1234 * 600 *
1235 * Also note that the function uses a somewha 601 * Also note that the function uses a somewhat relaxed locking scheme, so it may
1236 * be called only for an already offlined CPU 602 * be called only for an already offlined CPU.
1237 */ 603 */
1238 void clear_tasks_mm_cpumask(int cpu) 604 void clear_tasks_mm_cpumask(int cpu)
1239 { 605 {
1240 struct task_struct *p; 606 struct task_struct *p;
1241 607
1242 /* 608 /*
1243 * This function is called after the 609 * This function is called after the cpu is taken down and marked
1244 * offline, so its not like new tasks 610 * offline, so its not like new tasks will ever get this cpu set in
1245 * their mm mask. -- Peter Zijlstra 611 * their mm mask. -- Peter Zijlstra
1246 * Thus, we may use rcu_read_lock() h 612 * Thus, we may use rcu_read_lock() here, instead of grabbing
1247 * full-fledged tasklist_lock. 613 * full-fledged tasklist_lock.
1248 */ 614 */
1249 WARN_ON(cpu_online(cpu)); 615 WARN_ON(cpu_online(cpu));
1250 rcu_read_lock(); 616 rcu_read_lock();
1251 for_each_process(p) { 617 for_each_process(p) {
1252 struct task_struct *t; 618 struct task_struct *t;
1253 619
1254 /* 620 /*
1255 * Main thread might exit, bu 621 * Main thread might exit, but other threads may still have
1256 * a valid mm. Find one. 622 * a valid mm. Find one.
1257 */ 623 */
1258 t = find_lock_task_mm(p); 624 t = find_lock_task_mm(p);
1259 if (!t) 625 if (!t)
1260 continue; 626 continue;
1261 arch_clear_mm_cpumask_cpu(cpu !! 627 cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
1262 task_unlock(t); 628 task_unlock(t);
1263 } 629 }
1264 rcu_read_unlock(); 630 rcu_read_unlock();
1265 } 631 }
1266 632
>> 633 static inline void check_for_tasks(int dead_cpu)
>> 634 {
>> 635 struct task_struct *g, *p;
>> 636
>> 637 read_lock(&tasklist_lock);
>> 638 for_each_process_thread(g, p) {
>> 639 if (!p->on_rq)
>> 640 continue;
>> 641 /*
>> 642 * We do the check with unlocked task_rq(p)->lock.
>> 643 * Order the reading to do not warn about a task,
>> 644 * which was running on this cpu in the past, and
>> 645 * it's just been woken on another cpu.
>> 646 */
>> 647 rmb();
>> 648 if (task_cpu(p) != dead_cpu)
>> 649 continue;
>> 650
>> 651 pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
>> 652 p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
>> 653 }
>> 654 read_unlock(&tasklist_lock);
>> 655 }
>> 656
1267 /* Take this CPU down. */ 657 /* Take this CPU down. */
1268 static int take_cpu_down(void *_param) 658 static int take_cpu_down(void *_param)
1269 { 659 {
1270 struct cpuhp_cpu_state *st = this_cpu 660 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1271 enum cpuhp_state target = max((int)st 661 enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
1272 int err, cpu = smp_processor_id(); 662 int err, cpu = smp_processor_id();
1273 663
1274 /* Ensure this CPU doesn't handle any 664 /* Ensure this CPU doesn't handle any more interrupts. */
1275 err = __cpu_disable(); 665 err = __cpu_disable();
1276 if (err < 0) 666 if (err < 0)
1277 return err; 667 return err;
1278 668
1279 /* 669 /*
1280 * Must be called from CPUHP_TEARDOWN !! 670 * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not
1281 * down, that the current state is CP !! 671 * do this step again.
1282 */ <<
1283 WARN_ON(st->state != (CPUHP_TEARDOWN_ <<
1284 <<
1285 /* <<
1286 * Invoke the former CPU_DYING callba <<
1287 */ 672 */
1288 cpuhp_invoke_callback_range_nofail(fa !! 673 WARN_ON(st->state != CPUHP_TEARDOWN_CPU);
>> 674 st->state--;
>> 675 /* Invoke the former CPU_DYING callbacks */
>> 676 for (; st->state > target; st->state--)
>> 677 cpuhp_invoke_callback(cpu, st->state, false, NULL);
1289 678
>> 679 /* Give up timekeeping duties */
>> 680 tick_handover_do_timer();
1290 /* Park the stopper thread */ 681 /* Park the stopper thread */
1291 stop_machine_park(cpu); 682 stop_machine_park(cpu);
1292 return 0; 683 return 0;
1293 } 684 }
1294 685
1295 static int takedown_cpu(unsigned int cpu) 686 static int takedown_cpu(unsigned int cpu)
1296 { 687 {
1297 struct cpuhp_cpu_state *st = per_cpu_ 688 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1298 int err; 689 int err;
1299 690
1300 /* Park the smpboot threads */ 691 /* Park the smpboot threads */
1301 kthread_park(st->thread); !! 692 kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread);
>> 693 smpboot_park_threads(cpu);
1302 694
1303 /* 695 /*
1304 * Prevent irq alloc/free while the d 696 * Prevent irq alloc/free while the dying cpu reorganizes the
1305 * interrupt affinities. 697 * interrupt affinities.
1306 */ 698 */
1307 irq_lock_sparse(); 699 irq_lock_sparse();
1308 700
1309 /* 701 /*
1310 * So now all preempt/rcu users must 702 * So now all preempt/rcu users must observe !cpu_active().
1311 */ 703 */
1312 err = stop_machine_cpuslocked(take_cp !! 704 err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
1313 if (err) { 705 if (err) {
1314 /* CPU refused to die */ 706 /* CPU refused to die */
1315 irq_unlock_sparse(); 707 irq_unlock_sparse();
1316 /* Unpark the hotplug thread 708 /* Unpark the hotplug thread so we can rollback there */
1317 kthread_unpark(st->thread); !! 709 kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread);
1318 return err; 710 return err;
1319 } 711 }
1320 BUG_ON(cpu_online(cpu)); 712 BUG_ON(cpu_online(cpu));
1321 713
1322 /* 714 /*
1323 * The teardown callback for CPUHP_AP !! 715 * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all
1324 * all runnable tasks from the CPU, t !! 716 * runnable tasks from the cpu, there's only the idle task left now
1325 * that the migration thread is done 717 * that the migration thread is done doing the stop_machine thing.
1326 * 718 *
1327 * Wait for the stop thread to go awa 719 * Wait for the stop thread to go away.
1328 */ 720 */
1329 wait_for_ap_thread(st, false); !! 721 wait_for_completion(&st->done);
1330 BUG_ON(st->state != CPUHP_AP_IDLE_DEA 722 BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
1331 723
1332 /* Interrupts are moved away from the 724 /* Interrupts are moved away from the dying cpu, reenable alloc/free */
1333 irq_unlock_sparse(); 725 irq_unlock_sparse();
1334 726
1335 hotplug_cpu__broadcast_tick_pull(cpu) 727 hotplug_cpu__broadcast_tick_pull(cpu);
1336 /* This actually kills the CPU. */ 728 /* This actually kills the CPU. */
1337 __cpu_die(cpu); 729 __cpu_die(cpu);
1338 730
1339 cpuhp_bp_sync_dead(cpu); <<
1340 <<
1341 tick_cleanup_dead_cpu(cpu); 731 tick_cleanup_dead_cpu(cpu);
1342 <<
1343 /* <<
1344 * Callbacks must be re-integrated ri <<
1345 * Otherwise an RCU callback could bl <<
1346 * waiting for its completion. <<
1347 */ <<
1348 rcutree_migrate_callbacks(cpu); <<
1349 <<
1350 return 0; 732 return 0;
1351 } 733 }
1352 734
1353 static void cpuhp_complete_idle_dead(void *ar 735 static void cpuhp_complete_idle_dead(void *arg)
1354 { 736 {
1355 struct cpuhp_cpu_state *st = arg; 737 struct cpuhp_cpu_state *st = arg;
1356 738
1357 complete_ap_thread(st, false); !! 739 complete(&st->done);
1358 } 740 }
1359 741
1360 void cpuhp_report_idle_dead(void) 742 void cpuhp_report_idle_dead(void)
1361 { 743 {
1362 struct cpuhp_cpu_state *st = this_cpu 744 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1363 745
1364 BUG_ON(st->state != CPUHP_AP_OFFLINE) 746 BUG_ON(st->state != CPUHP_AP_OFFLINE);
1365 tick_assert_timekeeping_handover(); !! 747 rcu_report_dead(smp_processor_id());
1366 rcutree_report_cpu_dead(); <<
1367 st->state = CPUHP_AP_IDLE_DEAD; 748 st->state = CPUHP_AP_IDLE_DEAD;
1368 /* 749 /*
1369 * We cannot call complete after rcut !! 750 * We cannot call complete after rcu_report_dead() so we delegate it
1370 * to an online cpu. 751 * to an online cpu.
1371 */ 752 */
1372 smp_call_function_single(cpumask_firs 753 smp_call_function_single(cpumask_first(cpu_online_mask),
1373 cpuhp_comple 754 cpuhp_complete_idle_dead, st, 0);
1374 } 755 }
1375 756
1376 static int cpuhp_down_callbacks(unsigned int !! 757 #else
1377 enum cpuhp_st !! 758 #define takedown_cpu NULL
1378 { !! 759 #endif
1379 enum cpuhp_state prev_state = st->sta <<
1380 int ret = 0; <<
1381 <<
1382 ret = cpuhp_invoke_callback_range(fal <<
1383 if (ret) { <<
1384 pr_debug("CPU DOWN failed (%d <<
1385 ret, cpu, cpuhp_get_ <<
1386 st->state); <<
1387 <<
1388 cpuhp_reset_state(cpu, st, pr <<
1389 <<
1390 if (st->state < prev_state) <<
1391 WARN_ON(cpuhp_invoke_ <<
1392 <<
1393 } <<
1394 760
1395 return ret; !! 761 #ifdef CONFIG_HOTPLUG_CPU
1396 } <<
1397 762
1398 /* Requires cpu_add_remove_lock to be held */ 763 /* Requires cpu_add_remove_lock to be held */
1399 static int __ref _cpu_down(unsigned int cpu, 764 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
1400 enum cpuhp_state t 765 enum cpuhp_state target)
1401 { 766 {
1402 struct cpuhp_cpu_state *st = per_cpu_ 767 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1403 int prev_state, ret = 0; 768 int prev_state, ret = 0;
1404 769
1405 if (num_online_cpus() == 1) 770 if (num_online_cpus() == 1)
1406 return -EBUSY; 771 return -EBUSY;
1407 772
1408 if (!cpu_present(cpu)) 773 if (!cpu_present(cpu))
1409 return -EINVAL; 774 return -EINVAL;
1410 775
1411 cpus_write_lock(); !! 776 cpu_hotplug_begin();
1412 777
1413 cpuhp_tasks_frozen = tasks_frozen; 778 cpuhp_tasks_frozen = tasks_frozen;
1414 779
1415 prev_state = cpuhp_set_state(cpu, st, !! 780 prev_state = st->state;
>> 781 st->target = target;
1416 /* 782 /*
1417 * If the current CPU state is in the 783 * If the current CPU state is in the range of the AP hotplug thread,
1418 * then we need to kick the thread. 784 * then we need to kick the thread.
1419 */ 785 */
1420 if (st->state > CPUHP_TEARDOWN_CPU) { 786 if (st->state > CPUHP_TEARDOWN_CPU) {
1421 st->target = max((int)target, <<
1422 ret = cpuhp_kick_ap_work(cpu) 787 ret = cpuhp_kick_ap_work(cpu);
1423 /* 788 /*
1424 * The AP side has done the e 789 * The AP side has done the error rollback already. Just
1425 * return the error code.. 790 * return the error code..
1426 */ 791 */
1427 if (ret) 792 if (ret)
1428 goto out; 793 goto out;
1429 794
1430 /* 795 /*
1431 * We might have stopped stil 796 * We might have stopped still in the range of the AP hotplug
1432 * thread. Nothing to do anym 797 * thread. Nothing to do anymore.
1433 */ 798 */
1434 if (st->state > CPUHP_TEARDOW 799 if (st->state > CPUHP_TEARDOWN_CPU)
1435 goto out; 800 goto out;
1436 <<
1437 st->target = target; <<
1438 } 801 }
1439 /* 802 /*
1440 * The AP brought itself down to CPUH 803 * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need
1441 * to do the further cleanups. 804 * to do the further cleanups.
1442 */ 805 */
1443 ret = cpuhp_down_callbacks(cpu, st, t 806 ret = cpuhp_down_callbacks(cpu, st, target);
1444 if (ret && st->state < prev_state) { !! 807 if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) {
1445 if (st->state == CPUHP_TEARDO !! 808 st->target = prev_state;
1446 cpuhp_reset_state(cpu !! 809 st->rollback = true;
1447 __cpuhp_kick_ap(st); !! 810 cpuhp_kick_ap_work(cpu);
1448 } else { <<
1449 WARN(1, "DEAD callbac <<
1450 } <<
1451 } 811 }
1452 812
1453 out: 813 out:
1454 cpus_write_unlock(); !! 814 cpu_hotplug_done();
1455 /* <<
1456 * Do post unplug cleanup. This is st <<
1457 * concurrent CPU hotplug via cpu_add <<
1458 */ <<
1459 lockup_detector_cleanup(); <<
1460 arch_smt_update(); <<
1461 return ret; 815 return ret;
1462 } 816 }
1463 817
1464 struct cpu_down_work { !! 818 static int do_cpu_down(unsigned int cpu, enum cpuhp_state target)
1465 unsigned int cpu; <<
1466 enum cpuhp_state target; <<
1467 }; <<
1468 <<
1469 static long __cpu_down_maps_locked(void *arg) <<
1470 { 819 {
1471 struct cpu_down_work *work = arg; !! 820 int err;
1472 <<
1473 return _cpu_down(work->cpu, 0, work-> <<
1474 } <<
1475 <<
1476 static int cpu_down_maps_locked(unsigned int <<
1477 { <<
1478 struct cpu_down_work work = { .cpu = <<
1479 821
1480 /* !! 822 cpu_maps_update_begin();
1481 * If the platform does not support h <<
1482 * differentiate it from a transient <<
1483 */ <<
1484 if (cpu_hotplug_offline_disabled) <<
1485 return -EOPNOTSUPP; <<
1486 if (cpu_hotplug_disabled) <<
1487 return -EBUSY; <<
1488 823
1489 /* !! 824 if (cpu_hotplug_disabled) {
1490 * Ensure that the control task does !! 825 err = -EBUSY;
1491 * CPU to prevent a deadlock against !! 826 goto out;
1492 * Also keep at least one housekeepin <<
1493 * an empty sched_domain span. <<
1494 */ <<
1495 for_each_cpu_and(cpu, cpu_online_mask <<
1496 if (cpu != work.cpu) <<
1497 return work_on_cpu(cp <<
1498 } 827 }
1499 return -EBUSY; <<
1500 } <<
1501 828
1502 static int cpu_down(unsigned int cpu, enum cp !! 829 err = _cpu_down(cpu, 0, target);
1503 { <<
1504 int err; <<
1505 830
1506 cpu_maps_update_begin(); !! 831 out:
1507 err = cpu_down_maps_locked(cpu, targe <<
1508 cpu_maps_update_done(); 832 cpu_maps_update_done();
1509 return err; 833 return err;
1510 } 834 }
1511 !! 835 int cpu_down(unsigned int cpu)
1512 /** <<
1513 * cpu_device_down - Bring down a cpu device <<
1514 * @dev: Pointer to the cpu device to offline <<
1515 * <<
1516 * This function is meant to be used by devic <<
1517 * <<
1518 * Other subsystems should use remove_cpu() i <<
1519 * <<
1520 * Return: %0 on success or a negative errno <<
1521 */ <<
1522 int cpu_device_down(struct device *dev) <<
1523 { <<
1524 return cpu_down(dev->id, CPUHP_OFFLIN <<
1525 } <<
1526 <<
1527 int remove_cpu(unsigned int cpu) <<
1528 { <<
1529 int ret; <<
1530 <<
1531 lock_device_hotplug(); <<
1532 ret = device_offline(get_cpu_device(c <<
1533 unlock_device_hotplug(); <<
1534 <<
1535 return ret; <<
1536 } <<
1537 EXPORT_SYMBOL_GPL(remove_cpu); <<
1538 <<
1539 void smp_shutdown_nonboot_cpus(unsigned int p <<
1540 { 836 {
1541 unsigned int cpu; !! 837 return do_cpu_down(cpu, CPUHP_OFFLINE);
1542 int error; <<
1543 <<
1544 cpu_maps_update_begin(); <<
1545 <<
1546 /* <<
1547 * Make certain the cpu I'm about to <<
1548 * <<
1549 * This is inline to what migrate_to_ <<
1550 */ <<
1551 if (!cpu_online(primary_cpu)) <<
1552 primary_cpu = cpumask_first(c <<
1553 <<
1554 for_each_online_cpu(cpu) { <<
1555 if (cpu == primary_cpu) <<
1556 continue; <<
1557 <<
1558 error = cpu_down_maps_locked( <<
1559 if (error) { <<
1560 pr_err("Failed to off <<
1561 cpu, error); <<
1562 break; <<
1563 } <<
1564 } <<
1565 <<
1566 /* <<
1567 * Ensure all but the reboot CPU are <<
1568 */ <<
1569 BUG_ON(num_online_cpus() > 1); <<
1570 <<
1571 /* <<
1572 * Make sure the CPUs won't be enable <<
1573 * point. Kexec will reboot to a new <<
1574 * everything along the way. <<
1575 */ <<
1576 cpu_hotplug_disabled++; <<
1577 <<
1578 cpu_maps_update_done(); <<
1579 } 838 }
1580 !! 839 EXPORT_SYMBOL(cpu_down);
1581 #else <<
1582 #define takedown_cpu NULL <<
1583 #endif /*CONFIG_HOTPLUG_CPU*/ 840 #endif /*CONFIG_HOTPLUG_CPU*/
1584 841
1585 /** 842 /**
1586 * notify_cpu_starting(cpu) - Invoke the call 843 * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
1587 * @cpu: cpu that just started 844 * @cpu: cpu that just started
1588 * 845 *
1589 * It must be called by the arch code on the 846 * It must be called by the arch code on the new cpu, before the new cpu
1590 * enables interrupts and before the "boot" c 847 * enables interrupts and before the "boot" cpu returns from __cpu_up().
1591 */ 848 */
1592 void notify_cpu_starting(unsigned int cpu) 849 void notify_cpu_starting(unsigned int cpu)
1593 { 850 {
1594 struct cpuhp_cpu_state *st = per_cpu_ 851 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1595 enum cpuhp_state target = min((int)st 852 enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
1596 853
1597 rcutree_report_cpu_starting(cpu); !! 854 rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
1598 cpumask_set_cpu(cpu, &cpus_booted_onc !! 855 while (st->state < target) {
1599 !! 856 st->state++;
1600 /* !! 857 cpuhp_invoke_callback(cpu, st->state, true, NULL);
1601 * STARTING must not fail! !! 858 }
1602 */ <<
1603 cpuhp_invoke_callback_range_nofail(tr <<
1604 } 859 }
1605 860
1606 /* 861 /*
1607 * Called from the idle task. Wake up the con !! 862 * Called from the idle task. We need to set active here, so we can kick off
1608 * hotplug thread of the upcoming CPU up and !! 863 * the stopper thread and unpark the smpboot threads. If the target state is
1609 * online bringup to the hotplug thread. !! 864 * beyond CPUHP_AP_ONLINE_IDLE we kick cpuhp thread and let it bring up the
>> 865 * cpu further.
1610 */ 866 */
1611 void cpuhp_online_idle(enum cpuhp_state state 867 void cpuhp_online_idle(enum cpuhp_state state)
1612 { 868 {
1613 struct cpuhp_cpu_state *st = this_cpu 869 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
>> 870 unsigned int cpu = smp_processor_id();
1614 871
1615 /* Happens for the boot cpu */ 872 /* Happens for the boot cpu */
1616 if (state != CPUHP_AP_ONLINE_IDLE) 873 if (state != CPUHP_AP_ONLINE_IDLE)
1617 return; 874 return;
1618 875
1619 cpuhp_ap_update_sync_state(SYNC_STATE !! 876 st->state = CPUHP_AP_ONLINE_IDLE;
1620 877
1621 /* !! 878 /* Unpark the stopper thread and the hotplug thread of this cpu */
1622 * Unpark the stopper thread before w !! 879 stop_machine_unpark(cpu);
1623 * scheduling); this ensures the stop !! 880 kthread_unpark(st->thread);
1624 */ <<
1625 stop_machine_unpark(smp_processor_id( <<
1626 881
1627 st->state = CPUHP_AP_ONLINE_IDLE; !! 882 /* Should we go further up ? */
1628 complete_ap_thread(st, true); !! 883 if (st->target > CPUHP_AP_ONLINE_IDLE)
>> 884 __cpuhp_kick_ap_work(st);
>> 885 else
>> 886 complete(&st->done);
1629 } 887 }
1630 888
1631 /* Requires cpu_add_remove_lock to be held */ 889 /* Requires cpu_add_remove_lock to be held */
1632 static int _cpu_up(unsigned int cpu, int task 890 static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
1633 { 891 {
1634 struct cpuhp_cpu_state *st = per_cpu_ 892 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1635 struct task_struct *idle; 893 struct task_struct *idle;
1636 int ret = 0; 894 int ret = 0;
1637 895
1638 cpus_write_lock(); !! 896 cpu_hotplug_begin();
1639 897
1640 if (!cpu_present(cpu)) { 898 if (!cpu_present(cpu)) {
1641 ret = -EINVAL; 899 ret = -EINVAL;
1642 goto out; 900 goto out;
1643 } 901 }
1644 902
1645 /* 903 /*
1646 * The caller of cpu_up() might have !! 904 * The caller of do_cpu_up might have raced with another
1647 * caller. Nothing to do. !! 905 * caller. Ignore it for now.
1648 */ 906 */
1649 if (st->state >= target) 907 if (st->state >= target)
1650 goto out; 908 goto out;
1651 909
1652 if (st->state == CPUHP_OFFLINE) { 910 if (st->state == CPUHP_OFFLINE) {
1653 /* Let it fail before we try 911 /* Let it fail before we try to bring the cpu up */
1654 idle = idle_thread_get(cpu); 912 idle = idle_thread_get(cpu);
1655 if (IS_ERR(idle)) { 913 if (IS_ERR(idle)) {
1656 ret = PTR_ERR(idle); 914 ret = PTR_ERR(idle);
1657 goto out; 915 goto out;
1658 } 916 }
1659 <<
1660 /* <<
1661 * Reset stale stack state fr <<
1662 */ <<
1663 scs_task_reset(idle); <<
1664 kasan_unpoison_task_stack(idl <<
1665 } 917 }
1666 918
1667 cpuhp_tasks_frozen = tasks_frozen; 919 cpuhp_tasks_frozen = tasks_frozen;
1668 920
1669 cpuhp_set_state(cpu, st, target); !! 921 st->target = target;
1670 /* 922 /*
1671 * If the current CPU state is in the 923 * If the current CPU state is in the range of the AP hotplug thread,
1672 * then we need to kick the thread on 924 * then we need to kick the thread once more.
1673 */ 925 */
1674 if (st->state > CPUHP_BRINGUP_CPU) { 926 if (st->state > CPUHP_BRINGUP_CPU) {
1675 ret = cpuhp_kick_ap_work(cpu) 927 ret = cpuhp_kick_ap_work(cpu);
1676 /* 928 /*
1677 * The AP side has done the e 929 * The AP side has done the error rollback already. Just
1678 * return the error code.. 930 * return the error code..
1679 */ 931 */
1680 if (ret) 932 if (ret)
1681 goto out; 933 goto out;
1682 } 934 }
1683 935
1684 /* 936 /*
1685 * Try to reach the target state. We 937 * Try to reach the target state. We max out on the BP at
1686 * CPUHP_BRINGUP_CPU. After that the 938 * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is
1687 * responsible for bringing it up to 939 * responsible for bringing it up to the target state.
1688 */ 940 */
1689 target = min((int)target, CPUHP_BRING 941 target = min((int)target, CPUHP_BRINGUP_CPU);
1690 ret = cpuhp_up_callbacks(cpu, st, tar 942 ret = cpuhp_up_callbacks(cpu, st, target);
1691 out: 943 out:
1692 cpus_write_unlock(); !! 944 cpu_hotplug_done();
1693 arch_smt_update(); <<
1694 return ret; 945 return ret;
1695 } 946 }
1696 947
1697 static int cpu_up(unsigned int cpu, enum cpuh !! 948 static int do_cpu_up(unsigned int cpu, enum cpuhp_state target)
1698 { 949 {
1699 int err = 0; 950 int err = 0;
1700 951
1701 if (!cpu_possible(cpu)) { 952 if (!cpu_possible(cpu)) {
1702 pr_err("can't online cpu %d b 953 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
1703 cpu); 954 cpu);
>> 955 #if defined(CONFIG_IA64)
>> 956 pr_err("please check additional_cpus= boot parameter\n");
>> 957 #endif
1704 return -EINVAL; 958 return -EINVAL;
1705 } 959 }
1706 960
1707 err = try_online_node(cpu_to_node(cpu 961 err = try_online_node(cpu_to_node(cpu));
1708 if (err) 962 if (err)
1709 return err; 963 return err;
1710 964
1711 cpu_maps_update_begin(); 965 cpu_maps_update_begin();
1712 966
1713 if (cpu_hotplug_disabled) { 967 if (cpu_hotplug_disabled) {
1714 err = -EBUSY; 968 err = -EBUSY;
1715 goto out; 969 goto out;
1716 } 970 }
1717 if (!cpu_bootable(cpu)) { <<
1718 err = -EPERM; <<
1719 goto out; <<
1720 } <<
1721 971
1722 err = _cpu_up(cpu, 0, target); 972 err = _cpu_up(cpu, 0, target);
1723 out: 973 out:
1724 cpu_maps_update_done(); 974 cpu_maps_update_done();
1725 return err; 975 return err;
1726 } 976 }
1727 977
1728 /** !! 978 int cpu_up(unsigned int cpu)
1729 * cpu_device_up - Bring up a cpu device <<
1730 * @dev: Pointer to the cpu device to online <<
1731 * <<
1732 * This function is meant to be used by devic <<
1733 * <<
1734 * Other subsystems should use add_cpu() inst <<
1735 * <<
1736 * Return: %0 on success or a negative errno <<
1737 */ <<
1738 int cpu_device_up(struct device *dev) <<
1739 { <<
1740 return cpu_up(dev->id, CPUHP_ONLINE); <<
1741 } <<
1742 <<
1743 int add_cpu(unsigned int cpu) <<
1744 { 979 {
1745 int ret; !! 980 return do_cpu_up(cpu, CPUHP_ONLINE);
1746 <<
1747 lock_device_hotplug(); <<
1748 ret = device_online(get_cpu_device(cp <<
1749 unlock_device_hotplug(); <<
1750 <<
1751 return ret; <<
1752 } <<
1753 EXPORT_SYMBOL_GPL(add_cpu); <<
1754 <<
1755 /** <<
1756 * bringup_hibernate_cpu - Bring up the CPU t <<
1757 * @sleep_cpu: The cpu we hibernated on and s <<
1758 * <<
1759 * On some architectures like arm64, we can h <<
1760 * wake up the CPU we hibernated on might be <<
1761 * using maxcpus= for example. <<
1762 * <<
1763 * Return: %0 on success or a negative errno <<
1764 */ <<
1765 int bringup_hibernate_cpu(unsigned int sleep_ <<
1766 { <<
1767 int ret; <<
1768 <<
1769 if (!cpu_online(sleep_cpu)) { <<
1770 pr_info("Hibernated on a CPU <<
1771 ret = cpu_up(sleep_cpu, CPUHP <<
1772 if (ret) { <<
1773 pr_err("Failed to bri <<
1774 return ret; <<
1775 } <<
1776 } <<
1777 return 0; <<
1778 } <<
1779 <<
1780 static void __init cpuhp_bringup_mask(const s <<
1781 enum cp <<
1782 { <<
1783 unsigned int cpu; <<
1784 <<
1785 for_each_cpu(cpu, mask) { <<
1786 struct cpuhp_cpu_state *st = <<
1787 <<
1788 if (cpu_up(cpu, target) && ca <<
1789 /* <<
1790 * If this failed the <<
1791 * rolled back to CPU <<
1792 * online. Clean it u <<
1793 */ <<
1794 WARN_ON(cpuhp_invoke_ <<
1795 } <<
1796 <<
1797 if (!--ncpus) <<
1798 break; <<
1799 } <<
1800 } <<
1801 <<
1802 #ifdef CONFIG_HOTPLUG_PARALLEL <<
1803 static bool __cpuhp_parallel_bringup __ro_aft <<
1804 <<
1805 static int __init parallel_bringup_parse_para <<
1806 { <<
1807 return kstrtobool(arg, &__cpuhp_paral <<
1808 } <<
1809 early_param("cpuhp.parallel", parallel_bringu <<
1810 <<
1811 #ifdef CONFIG_HOTPLUG_SMT <<
1812 static inline bool cpuhp_smt_aware(void) <<
1813 { <<
1814 return cpu_smt_max_threads > 1; <<
1815 } <<
1816 <<
1817 static inline const struct cpumask *cpuhp_get <<
1818 { <<
1819 return cpu_primary_thread_mask; <<
1820 } <<
1821 #else <<
1822 static inline bool cpuhp_smt_aware(void) <<
1823 { <<
1824 return false; <<
1825 } <<
1826 static inline const struct cpumask *cpuhp_get <<
1827 { <<
1828 return cpu_none_mask; <<
1829 } <<
1830 #endif <<
1831 <<
1832 bool __weak arch_cpuhp_init_parallel_bringup( <<
1833 { <<
1834 return true; <<
1835 } <<
1836 <<
1837 /* <<
1838 * On architectures which have enabled parall <<
1839 * prepare states for each of the to be onlin <<
1840 * sends the startup IPI to the APs. The APs <<
1841 * bringup code in parallel and then wait for <<
1842 * them one by one for the final onlining pro <<
1843 * <<
1844 * This avoids waiting for each AP to respond <<
1845 * CPUHP_BRINGUP_CPU. <<
1846 */ <<
1847 static bool __init cpuhp_bringup_cpus_paralle <<
1848 { <<
1849 const struct cpumask *mask = cpu_pres <<
1850 <<
1851 if (__cpuhp_parallel_bringup) <<
1852 __cpuhp_parallel_bringup = ar <<
1853 if (!__cpuhp_parallel_bringup) <<
1854 return false; <<
1855 <<
1856 if (cpuhp_smt_aware()) { <<
1857 const struct cpumask *pmask = <<
1858 static struct cpumask tmp_mas <<
1859 <<
1860 /* <<
1861 * X86 requires to prevent th <<
1862 * the primary thread does a <<
1863 * reasons. Bring the primary <<
1864 */ <<
1865 cpumask_and(&tmp_mask, mask, <<
1866 cpuhp_bringup_mask(&tmp_mask, <<
1867 cpuhp_bringup_mask(&tmp_mask, <<
1868 /* Account for the online CPU <<
1869 ncpus -= num_online_cpus(); <<
1870 if (!ncpus) <<
1871 return true; <<
1872 /* Create the mask for second <<
1873 cpumask_andnot(&tmp_mask, mas <<
1874 mask = &tmp_mask; <<
1875 } <<
1876 <<
1877 /* Bring the not-yet started CPUs up <<
1878 cpuhp_bringup_mask(mask, ncpus, CPUHP <<
1879 cpuhp_bringup_mask(mask, ncpus, CPUHP <<
1880 return true; <<
1881 } <<
1882 #else <<
1883 static inline bool cpuhp_bringup_cpus_paralle <<
1884 #endif /* CONFIG_HOTPLUG_PARALLEL */ <<
1885 <<
1886 void __init bringup_nonboot_cpus(unsigned int <<
1887 { <<
1888 if (!max_cpus) <<
1889 return; <<
1890 <<
1891 /* Try parallel bringup optimization <<
1892 if (cpuhp_bringup_cpus_parallel(max_c <<
1893 return; <<
1894 <<
1895 /* Full per CPU serialized bringup */ <<
1896 cpuhp_bringup_mask(cpu_present_mask, <<
1897 } 981 }
>> 982 EXPORT_SYMBOL_GPL(cpu_up);
1898 983
1899 #ifdef CONFIG_PM_SLEEP_SMP 984 #ifdef CONFIG_PM_SLEEP_SMP
1900 static cpumask_var_t frozen_cpus; 985 static cpumask_var_t frozen_cpus;
1901 986
1902 int freeze_secondary_cpus(int primary) 987 int freeze_secondary_cpus(int primary)
1903 { 988 {
1904 int cpu, error = 0; 989 int cpu, error = 0;
1905 990
1906 cpu_maps_update_begin(); 991 cpu_maps_update_begin();
1907 if (primary == -1) { !! 992 if (!cpu_online(primary))
1908 primary = cpumask_first(cpu_o 993 primary = cpumask_first(cpu_online_mask);
1909 if (!housekeeping_cpu(primary <<
1910 primary = housekeepin <<
1911 } else { <<
1912 if (!cpu_online(primary)) <<
1913 primary = cpumask_fir <<
1914 } <<
1915 <<
1916 /* 994 /*
1917 * We take down all of the non-boot C 995 * We take down all of the non-boot CPUs in one shot to avoid races
1918 * with the userspace trying to use t 996 * with the userspace trying to use the CPU hotplug at the same time
1919 */ 997 */
1920 cpumask_clear(frozen_cpus); 998 cpumask_clear(frozen_cpus);
1921 999
1922 pr_info("Disabling non-boot CPUs ...\ 1000 pr_info("Disabling non-boot CPUs ...\n");
1923 for (cpu = nr_cpu_ids - 1; cpu >= 0; !! 1001 for_each_online_cpu(cpu) {
1924 if (!cpu_online(cpu) || cpu = !! 1002 if (cpu == primary)
1925 continue; 1003 continue;
1926 <<
1927 if (pm_wakeup_pending()) { <<
1928 pr_info("Wakeup pendi <<
1929 error = -EBUSY; <<
1930 break; <<
1931 } <<
1932 <<
1933 trace_suspend_resume(TPS("CPU 1004 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
1934 error = _cpu_down(cpu, 1, CPU 1005 error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
1935 trace_suspend_resume(TPS("CPU 1006 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
1936 if (!error) 1007 if (!error)
1937 cpumask_set_cpu(cpu, 1008 cpumask_set_cpu(cpu, frozen_cpus);
1938 else { 1009 else {
1939 pr_err("Error taking 1010 pr_err("Error taking CPU%d down: %d\n", cpu, error);
1940 break; 1011 break;
1941 } 1012 }
1942 } 1013 }
1943 1014
1944 if (!error) 1015 if (!error)
1945 BUG_ON(num_online_cpus() > 1) 1016 BUG_ON(num_online_cpus() > 1);
1946 else 1017 else
1947 pr_err("Non-boot CPUs are not 1018 pr_err("Non-boot CPUs are not disabled\n");
1948 1019
1949 /* 1020 /*
1950 * Make sure the CPUs won't be enable 1021 * Make sure the CPUs won't be enabled by someone else. We need to do
1951 * this even in case of failure as al !! 1022 * this even in case of failure as all disable_nonboot_cpus() users are
1952 * supposed to do thaw_secondary_cpus !! 1023 * supposed to do enable_nonboot_cpus() on the failure path.
1953 */ 1024 */
1954 cpu_hotplug_disabled++; 1025 cpu_hotplug_disabled++;
1955 1026
1956 cpu_maps_update_done(); 1027 cpu_maps_update_done();
1957 return error; 1028 return error;
1958 } 1029 }
1959 1030
1960 void __weak arch_thaw_secondary_cpus_begin(vo !! 1031 void __weak arch_enable_nonboot_cpus_begin(void)
1961 { 1032 {
1962 } 1033 }
1963 1034
1964 void __weak arch_thaw_secondary_cpus_end(void !! 1035 void __weak arch_enable_nonboot_cpus_end(void)
1965 { 1036 {
1966 } 1037 }
1967 1038
1968 void thaw_secondary_cpus(void) !! 1039 void enable_nonboot_cpus(void)
1969 { 1040 {
1970 int cpu, error; 1041 int cpu, error;
1971 1042
1972 /* Allow everyone to use the CPU hotp 1043 /* Allow everyone to use the CPU hotplug again */
1973 cpu_maps_update_begin(); 1044 cpu_maps_update_begin();
1974 __cpu_hotplug_enable(); 1045 __cpu_hotplug_enable();
1975 if (cpumask_empty(frozen_cpus)) 1046 if (cpumask_empty(frozen_cpus))
1976 goto out; 1047 goto out;
1977 1048
1978 pr_info("Enabling non-boot CPUs ...\n 1049 pr_info("Enabling non-boot CPUs ...\n");
1979 1050
1980 arch_thaw_secondary_cpus_begin(); !! 1051 arch_enable_nonboot_cpus_begin();
1981 1052
1982 for_each_cpu(cpu, frozen_cpus) { 1053 for_each_cpu(cpu, frozen_cpus) {
1983 trace_suspend_resume(TPS("CPU 1054 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
1984 error = _cpu_up(cpu, 1, CPUHP 1055 error = _cpu_up(cpu, 1, CPUHP_ONLINE);
1985 trace_suspend_resume(TPS("CPU 1056 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
1986 if (!error) { 1057 if (!error) {
1987 pr_info("CPU%d is up\ 1058 pr_info("CPU%d is up\n", cpu);
1988 continue; 1059 continue;
1989 } 1060 }
1990 pr_warn("Error taking CPU%d u 1061 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
1991 } 1062 }
1992 1063
1993 arch_thaw_secondary_cpus_end(); !! 1064 arch_enable_nonboot_cpus_end();
1994 1065
1995 cpumask_clear(frozen_cpus); 1066 cpumask_clear(frozen_cpus);
1996 out: 1067 out:
1997 cpu_maps_update_done(); 1068 cpu_maps_update_done();
1998 } 1069 }
1999 1070
2000 static int __init alloc_frozen_cpus(void) 1071 static int __init alloc_frozen_cpus(void)
2001 { 1072 {
2002 if (!alloc_cpumask_var(&frozen_cpus, 1073 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
2003 return -ENOMEM; 1074 return -ENOMEM;
2004 return 0; 1075 return 0;
2005 } 1076 }
2006 core_initcall(alloc_frozen_cpus); 1077 core_initcall(alloc_frozen_cpus);
2007 1078
2008 /* 1079 /*
2009 * When callbacks for CPU hotplug notificatio 1080 * When callbacks for CPU hotplug notifications are being executed, we must
2010 * ensure that the state of the system with r 1081 * ensure that the state of the system with respect to the tasks being frozen
2011 * or not, as reported by the notification, r 1082 * or not, as reported by the notification, remains unchanged *throughout the
2012 * duration* of the execution of the callback 1083 * duration* of the execution of the callbacks.
2013 * Hence we need to prevent the freezer from 1084 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
2014 * 1085 *
2015 * This synchronization is implemented by mut 1086 * This synchronization is implemented by mutually excluding regular CPU
2016 * hotplug and Suspend/Hibernate call paths b 1087 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
2017 * Hibernate notifications. 1088 * Hibernate notifications.
2018 */ 1089 */
2019 static int 1090 static int
2020 cpu_hotplug_pm_callback(struct notifier_block 1091 cpu_hotplug_pm_callback(struct notifier_block *nb,
2021 unsigned long action, 1092 unsigned long action, void *ptr)
2022 { 1093 {
2023 switch (action) { 1094 switch (action) {
2024 1095
2025 case PM_SUSPEND_PREPARE: 1096 case PM_SUSPEND_PREPARE:
2026 case PM_HIBERNATION_PREPARE: 1097 case PM_HIBERNATION_PREPARE:
2027 cpu_hotplug_disable(); 1098 cpu_hotplug_disable();
2028 break; 1099 break;
2029 1100
2030 case PM_POST_SUSPEND: 1101 case PM_POST_SUSPEND:
2031 case PM_POST_HIBERNATION: 1102 case PM_POST_HIBERNATION:
2032 cpu_hotplug_enable(); 1103 cpu_hotplug_enable();
2033 break; 1104 break;
2034 1105
2035 default: 1106 default:
2036 return NOTIFY_DONE; 1107 return NOTIFY_DONE;
2037 } 1108 }
2038 1109
2039 return NOTIFY_OK; 1110 return NOTIFY_OK;
2040 } 1111 }
2041 1112
2042 1113
2043 static int __init cpu_hotplug_pm_sync_init(vo 1114 static int __init cpu_hotplug_pm_sync_init(void)
2044 { 1115 {
2045 /* 1116 /*
2046 * cpu_hotplug_pm_callback has higher 1117 * cpu_hotplug_pm_callback has higher priority than x86
2047 * bsp_pm_callback which depends on c 1118 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
2048 * to disable cpu hotplug to avoid cp 1119 * to disable cpu hotplug to avoid cpu hotplug race.
2049 */ 1120 */
2050 pm_notifier(cpu_hotplug_pm_callback, 1121 pm_notifier(cpu_hotplug_pm_callback, 0);
2051 return 0; 1122 return 0;
2052 } 1123 }
2053 core_initcall(cpu_hotplug_pm_sync_init); 1124 core_initcall(cpu_hotplug_pm_sync_init);
2054 1125
2055 #endif /* CONFIG_PM_SLEEP_SMP */ 1126 #endif /* CONFIG_PM_SLEEP_SMP */
2056 1127
2057 int __boot_cpu_id; <<
2058 <<
2059 #endif /* CONFIG_SMP */ 1128 #endif /* CONFIG_SMP */
2060 1129
2061 /* Boot processor state steps */ 1130 /* Boot processor state steps */
2062 static struct cpuhp_step cpuhp_hp_states[] = !! 1131 static struct cpuhp_step cpuhp_bp_states[] = {
2063 [CPUHP_OFFLINE] = { 1132 [CPUHP_OFFLINE] = {
2064 .name = "of 1133 .name = "offline",
2065 .startup.single = NUL 1134 .startup.single = NULL,
2066 .teardown.single = NUL 1135 .teardown.single = NULL,
2067 }, 1136 },
2068 #ifdef CONFIG_SMP 1137 #ifdef CONFIG_SMP
2069 [CPUHP_CREATE_THREADS]= { 1138 [CPUHP_CREATE_THREADS]= {
2070 .name = "th 1139 .name = "threads:prepare",
2071 .startup.single = smp 1140 .startup.single = smpboot_create_threads,
2072 .teardown.single = NUL 1141 .teardown.single = NULL,
2073 .cant_stop = tru 1142 .cant_stop = true,
2074 }, 1143 },
2075 [CPUHP_PERF_PREPARE] = { 1144 [CPUHP_PERF_PREPARE] = {
2076 .name = "pe 1145 .name = "perf:prepare",
2077 .startup.single = per 1146 .startup.single = perf_event_init_cpu,
2078 .teardown.single = per 1147 .teardown.single = perf_event_exit_cpu,
2079 }, 1148 },
2080 [CPUHP_RANDOM_PREPARE] = { <<
2081 .name = "ra <<
2082 .startup.single = ran <<
2083 .teardown.single = NUL <<
2084 }, <<
2085 [CPUHP_WORKQUEUE_PREP] = { 1149 [CPUHP_WORKQUEUE_PREP] = {
2086 .name = "wo 1150 .name = "workqueue:prepare",
2087 .startup.single = wor 1151 .startup.single = workqueue_prepare_cpu,
2088 .teardown.single = NUL 1152 .teardown.single = NULL,
2089 }, 1153 },
2090 [CPUHP_HRTIMERS_PREPARE] = { 1154 [CPUHP_HRTIMERS_PREPARE] = {
2091 .name = "hr 1155 .name = "hrtimers:prepare",
2092 .startup.single = hrt 1156 .startup.single = hrtimers_prepare_cpu,
2093 .teardown.single = NUL !! 1157 .teardown.single = hrtimers_dead_cpu,
2094 }, 1158 },
2095 [CPUHP_SMPCFD_PREPARE] = { 1159 [CPUHP_SMPCFD_PREPARE] = {
2096 .name = "sm 1160 .name = "smpcfd:prepare",
2097 .startup.single = smp 1161 .startup.single = smpcfd_prepare_cpu,
2098 .teardown.single = smp 1162 .teardown.single = smpcfd_dead_cpu,
2099 }, 1163 },
2100 [CPUHP_RELAY_PREPARE] = { 1164 [CPUHP_RELAY_PREPARE] = {
2101 .name = "re 1165 .name = "relay:prepare",
2102 .startup.single = rel 1166 .startup.single = relay_prepare_cpu,
2103 .teardown.single = NUL 1167 .teardown.single = NULL,
2104 }, 1168 },
>> 1169 [CPUHP_SLAB_PREPARE] = {
>> 1170 .name = "slab:prepare",
>> 1171 .startup.single = slab_prepare_cpu,
>> 1172 .teardown.single = slab_dead_cpu,
>> 1173 },
2105 [CPUHP_RCUTREE_PREP] = { 1174 [CPUHP_RCUTREE_PREP] = {
2106 .name = "RC 1175 .name = "RCU/tree:prepare",
2107 .startup.single = rcu 1176 .startup.single = rcutree_prepare_cpu,
2108 .teardown.single = rcu 1177 .teardown.single = rcutree_dead_cpu,
2109 }, 1178 },
2110 /* 1179 /*
2111 * On the tear-down path, timers_dead 1180 * On the tear-down path, timers_dead_cpu() must be invoked
2112 * before blk_mq_queue_reinit_notify( 1181 * before blk_mq_queue_reinit_notify() from notify_dead(),
2113 * otherwise a RCU stall occurs. 1182 * otherwise a RCU stall occurs.
2114 */ 1183 */
2115 [CPUHP_TIMERS_PREPARE] = { !! 1184 [CPUHP_TIMERS_DEAD] = {
2116 .name = "ti !! 1185 .name = "timers:dead",
2117 .startup.single = tim !! 1186 .startup.single = NULL,
2118 .teardown.single = tim 1187 .teardown.single = timers_dead_cpu,
2119 }, 1188 },
2120 !! 1189 /* Kicks the plugged cpu into life */
2121 #ifdef CONFIG_HOTPLUG_SPLIT_STARTUP <<
2122 /* <<
2123 * Kicks the AP alive. AP will wait i <<
2124 * the next step will release it. <<
2125 */ <<
2126 [CPUHP_BP_KICK_AP] = { <<
2127 .name = "cp <<
2128 .startup.single = cpu <<
2129 }, <<
2130 <<
2131 /* <<
2132 * Waits for the AP to reach cpuhp_ap <<
2133 * releases it for the complete bring <<
2134 */ <<
2135 [CPUHP_BRINGUP_CPU] = { 1190 [CPUHP_BRINGUP_CPU] = {
2136 .name = "cp 1191 .name = "cpu:bringup",
2137 .startup.single = cpu !! 1192 .startup.single = bringup_cpu,
2138 .teardown.single = fin !! 1193 .teardown.single = NULL,
2139 .cant_stop = tru 1194 .cant_stop = true,
2140 }, 1195 },
2141 #else !! 1196 [CPUHP_AP_SMPCFD_DYING] = {
>> 1197 .name = "smpcfd:dying",
>> 1198 .startup.single = NULL,
>> 1199 .teardown.single = smpcfd_dying_cpu,
>> 1200 },
2142 /* 1201 /*
2143 * All-in-one CPU bringup state which !! 1202 * Handled on controll processor until the plugged processor manages
>> 1203 * this itself.
2144 */ 1204 */
2145 [CPUHP_BRINGUP_CPU] = { !! 1205 [CPUHP_TEARDOWN_CPU] = {
2146 .name = "cp !! 1206 .name = "cpu:teardown",
2147 .startup.single = bri !! 1207 .startup.single = NULL,
2148 .teardown.single = fin !! 1208 .teardown.single = takedown_cpu,
2149 .cant_stop = tru 1209 .cant_stop = true,
2150 }, 1210 },
>> 1211 #else
>> 1212 [CPUHP_BRINGUP_CPU] = { },
2151 #endif 1213 #endif
>> 1214 };
>> 1215
>> 1216 /* Application processor state steps */
>> 1217 static struct cpuhp_step cpuhp_ap_states[] = {
>> 1218 #ifdef CONFIG_SMP
2152 /* Final state before CPU kills itsel 1219 /* Final state before CPU kills itself */
2153 [CPUHP_AP_IDLE_DEAD] = { 1220 [CPUHP_AP_IDLE_DEAD] = {
2154 .name = "id 1221 .name = "idle:dead",
2155 }, 1222 },
2156 /* 1223 /*
2157 * Last state before CPU enters the i 1224 * Last state before CPU enters the idle loop to die. Transient state
2158 * for synchronization. 1225 * for synchronization.
2159 */ 1226 */
2160 [CPUHP_AP_OFFLINE] = { 1227 [CPUHP_AP_OFFLINE] = {
2161 .name = "ap 1228 .name = "ap:offline",
2162 .cant_stop = tru 1229 .cant_stop = true,
2163 }, 1230 },
2164 /* First state is scheduler control. 1231 /* First state is scheduler control. Interrupts are disabled */
2165 [CPUHP_AP_SCHED_STARTING] = { 1232 [CPUHP_AP_SCHED_STARTING] = {
2166 .name = "sc 1233 .name = "sched:starting",
2167 .startup.single = sch 1234 .startup.single = sched_cpu_starting,
2168 .teardown.single = sch 1235 .teardown.single = sched_cpu_dying,
2169 }, 1236 },
2170 [CPUHP_AP_RCUTREE_DYING] = { 1237 [CPUHP_AP_RCUTREE_DYING] = {
2171 .name = "RC 1238 .name = "RCU/tree:dying",
2172 .startup.single = NUL 1239 .startup.single = NULL,
2173 .teardown.single = rcu 1240 .teardown.single = rcutree_dying_cpu,
2174 }, 1241 },
2175 [CPUHP_AP_SMPCFD_DYING] = { <<
2176 .name = "sm <<
2177 .startup.single = NUL <<
2178 .teardown.single = smp <<
2179 }, <<
2180 [CPUHP_AP_HRTIMERS_DYING] = { <<
2181 .name = "hr <<
2182 .startup.single = NUL <<
2183 .teardown.single = hrt <<
2184 }, <<
2185 [CPUHP_AP_TICK_DYING] = { <<
2186 .name = "ti <<
2187 .startup.single = NUL <<
2188 .teardown.single = tic <<
2189 }, <<
2190 /* Entry state on starting. Interrupt 1242 /* Entry state on starting. Interrupts enabled from here on. Transient
2191 * state for synchronsization */ 1243 * state for synchronsization */
2192 [CPUHP_AP_ONLINE] = { 1244 [CPUHP_AP_ONLINE] = {
2193 .name = "ap 1245 .name = "ap:online",
2194 }, 1246 },
2195 /* <<
2196 * Handled on control processor until <<
2197 * this itself. <<
2198 */ <<
2199 [CPUHP_TEARDOWN_CPU] = { <<
2200 .name = "cp <<
2201 .startup.single = NUL <<
2202 .teardown.single = tak <<
2203 .cant_stop = tru <<
2204 }, <<
2205 <<
2206 [CPUHP_AP_SCHED_WAIT_EMPTY] = { <<
2207 .name = "sc <<
2208 .startup.single = NUL <<
2209 .teardown.single = sch <<
2210 }, <<
2211 <<
2212 /* Handle smpboot threads park/unpark 1247 /* Handle smpboot threads park/unpark */
2213 [CPUHP_AP_SMPBOOT_THREADS] = { 1248 [CPUHP_AP_SMPBOOT_THREADS] = {
2214 .name = "sm 1249 .name = "smpboot/threads:online",
2215 .startup.single = smp 1250 .startup.single = smpboot_unpark_threads,
2216 .teardown.single = smp <<
2217 }, <<
2218 [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { <<
2219 .name = "ir <<
2220 .startup.single = irq <<
2221 .teardown.single = NUL 1251 .teardown.single = NULL,
2222 }, 1252 },
2223 [CPUHP_AP_PERF_ONLINE] = { 1253 [CPUHP_AP_PERF_ONLINE] = {
2224 .name = "pe 1254 .name = "perf:online",
2225 .startup.single = per 1255 .startup.single = perf_event_init_cpu,
2226 .teardown.single = per 1256 .teardown.single = perf_event_exit_cpu,
2227 }, 1257 },
2228 [CPUHP_AP_WATCHDOG_ONLINE] = { <<
2229 .name = "lo <<
2230 .startup.single = loc <<
2231 .teardown.single = loc <<
2232 }, <<
2233 [CPUHP_AP_WORKQUEUE_ONLINE] = { 1258 [CPUHP_AP_WORKQUEUE_ONLINE] = {
2234 .name = "wo 1259 .name = "workqueue:online",
2235 .startup.single = wor 1260 .startup.single = workqueue_online_cpu,
2236 .teardown.single = wor 1261 .teardown.single = workqueue_offline_cpu,
2237 }, 1262 },
2238 [CPUHP_AP_RANDOM_ONLINE] = { <<
2239 .name = "ra <<
2240 .startup.single = ran <<
2241 .teardown.single = NUL <<
2242 }, <<
2243 [CPUHP_AP_RCUTREE_ONLINE] = { 1263 [CPUHP_AP_RCUTREE_ONLINE] = {
2244 .name = "RC 1264 .name = "RCU/tree:online",
2245 .startup.single = rcu 1265 .startup.single = rcutree_online_cpu,
2246 .teardown.single = rcu 1266 .teardown.single = rcutree_offline_cpu,
2247 }, 1267 },
2248 #endif 1268 #endif
2249 /* 1269 /*
2250 * The dynamically registered state s 1270 * The dynamically registered state space is here
2251 */ 1271 */
2252 1272
2253 #ifdef CONFIG_SMP 1273 #ifdef CONFIG_SMP
2254 /* Last state is scheduler control se 1274 /* Last state is scheduler control setting the cpu active */
2255 [CPUHP_AP_ACTIVE] = { 1275 [CPUHP_AP_ACTIVE] = {
2256 .name = "sc 1276 .name = "sched:active",
2257 .startup.single = sch 1277 .startup.single = sched_cpu_activate,
2258 .teardown.single = sch 1278 .teardown.single = sched_cpu_deactivate,
2259 }, 1279 },
2260 #endif 1280 #endif
2261 1281
2262 /* CPU is fully up and running. */ 1282 /* CPU is fully up and running. */
2263 [CPUHP_ONLINE] = { 1283 [CPUHP_ONLINE] = {
2264 .name = "on 1284 .name = "online",
2265 .startup.single = NUL 1285 .startup.single = NULL,
2266 .teardown.single = NUL 1286 .teardown.single = NULL,
2267 }, 1287 },
2268 }; 1288 };
2269 1289
2270 /* Sanity check for callbacks */ 1290 /* Sanity check for callbacks */
2271 static int cpuhp_cb_check(enum cpuhp_state st 1291 static int cpuhp_cb_check(enum cpuhp_state state)
2272 { 1292 {
2273 if (state <= CPUHP_OFFLINE || state > 1293 if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE)
2274 return -EINVAL; 1294 return -EINVAL;
2275 return 0; 1295 return 0;
2276 } 1296 }
2277 1297
2278 /* 1298 /*
2279 * Returns a free for dynamic slot assignment 1299 * Returns a free for dynamic slot assignment of the Online state. The states
2280 * are protected by the cpuhp_slot_states mut 1300 * are protected by the cpuhp_slot_states mutex and an empty slot is identified
2281 * by having no name assigned. 1301 * by having no name assigned.
2282 */ 1302 */
2283 static int cpuhp_reserve_state(enum cpuhp_sta 1303 static int cpuhp_reserve_state(enum cpuhp_state state)
2284 { 1304 {
2285 enum cpuhp_state i, end; 1305 enum cpuhp_state i, end;
2286 struct cpuhp_step *step; 1306 struct cpuhp_step *step;
2287 1307
2288 switch (state) { 1308 switch (state) {
2289 case CPUHP_AP_ONLINE_DYN: 1309 case CPUHP_AP_ONLINE_DYN:
2290 step = cpuhp_hp_states + CPUH !! 1310 step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN;
2291 end = CPUHP_AP_ONLINE_DYN_END 1311 end = CPUHP_AP_ONLINE_DYN_END;
2292 break; 1312 break;
2293 case CPUHP_BP_PREPARE_DYN: 1313 case CPUHP_BP_PREPARE_DYN:
2294 step = cpuhp_hp_states + CPUH !! 1314 step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN;
2295 end = CPUHP_BP_PREPARE_DYN_EN 1315 end = CPUHP_BP_PREPARE_DYN_END;
2296 break; 1316 break;
2297 default: 1317 default:
2298 return -EINVAL; 1318 return -EINVAL;
2299 } 1319 }
2300 1320
2301 for (i = state; i <= end; i++, step++ 1321 for (i = state; i <= end; i++, step++) {
2302 if (!step->name) 1322 if (!step->name)
2303 return i; 1323 return i;
2304 } 1324 }
2305 WARN(1, "No more dynamic states avail 1325 WARN(1, "No more dynamic states available for CPU hotplug\n");
2306 return -ENOSPC; 1326 return -ENOSPC;
2307 } 1327 }
2308 1328
2309 static int cpuhp_store_callbacks(enum cpuhp_s 1329 static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name,
2310 int (*startu 1330 int (*startup)(unsigned int cpu),
2311 int (*teardo 1331 int (*teardown)(unsigned int cpu),
2312 bool multi_i 1332 bool multi_instance)
2313 { 1333 {
2314 /* (Un)Install the callbacks for furt 1334 /* (Un)Install the callbacks for further cpu hotplug operations */
2315 struct cpuhp_step *sp; 1335 struct cpuhp_step *sp;
2316 int ret = 0; 1336 int ret = 0;
2317 1337
2318 /* !! 1338 if (state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN) {
2319 * If name is NULL, then the state ge <<
2320 * <<
2321 * CPUHP_AP_ONLINE_DYN and CPUHP_BP_P <<
2322 * the first allocation from these dy <<
2323 * would trigger a new allocation and <<
2324 * empty) state, leaving the callback <<
2325 * dangling, which causes wreckage on <<
2326 */ <<
2327 if (name && (state == CPUHP_AP_ONLINE <<
2328 state == CPUHP_BP_PREPAR <<
2329 ret = cpuhp_reserve_state(sta 1339 ret = cpuhp_reserve_state(state);
2330 if (ret < 0) 1340 if (ret < 0)
2331 return ret; 1341 return ret;
2332 state = ret; 1342 state = ret;
2333 } 1343 }
2334 sp = cpuhp_get_step(state); 1344 sp = cpuhp_get_step(state);
2335 if (name && sp->name) 1345 if (name && sp->name)
2336 return -EBUSY; 1346 return -EBUSY;
2337 1347
2338 sp->startup.single = startup; 1348 sp->startup.single = startup;
2339 sp->teardown.single = teardown; 1349 sp->teardown.single = teardown;
2340 sp->name = name; 1350 sp->name = name;
2341 sp->multi_instance = multi_instance; 1351 sp->multi_instance = multi_instance;
2342 INIT_HLIST_HEAD(&sp->list); 1352 INIT_HLIST_HEAD(&sp->list);
2343 return ret; 1353 return ret;
2344 } 1354 }
2345 1355
2346 static void *cpuhp_get_teardown_cb(enum cpuhp 1356 static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
2347 { 1357 {
2348 return cpuhp_get_step(state)->teardow 1358 return cpuhp_get_step(state)->teardown.single;
2349 } 1359 }
2350 1360
2351 /* 1361 /*
2352 * Call the startup/teardown function for a s 1362 * Call the startup/teardown function for a step either on the AP or
2353 * on the current CPU. 1363 * on the current CPU.
2354 */ 1364 */
2355 static int cpuhp_issue_call(int cpu, enum cpu 1365 static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup,
2356 struct hlist_node 1366 struct hlist_node *node)
2357 { 1367 {
2358 struct cpuhp_step *sp = cpuhp_get_ste 1368 struct cpuhp_step *sp = cpuhp_get_step(state);
2359 int ret; 1369 int ret;
2360 1370
2361 /* !! 1371 if ((bringup && !sp->startup.single) ||
2362 * If there's nothing to do, we done. !! 1372 (!bringup && !sp->teardown.single))
2363 * Relies on the union for multi_inst <<
2364 */ <<
2365 if (cpuhp_step_empty(bringup, sp)) <<
2366 return 0; 1373 return 0;
2367 /* 1374 /*
2368 * The non AP bound callbacks can fai 1375 * The non AP bound callbacks can fail on bringup. On teardown
2369 * e.g. module removal we crash for n 1376 * e.g. module removal we crash for now.
2370 */ 1377 */
2371 #ifdef CONFIG_SMP 1378 #ifdef CONFIG_SMP
2372 if (cpuhp_is_ap_state(state)) 1379 if (cpuhp_is_ap_state(state))
2373 ret = cpuhp_invoke_ap_callbac 1380 ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node);
2374 else 1381 else
2375 ret = cpuhp_invoke_callback(c !! 1382 ret = cpuhp_invoke_callback(cpu, state, bringup, node);
2376 #else 1383 #else
2377 ret = cpuhp_invoke_callback(cpu, stat !! 1384 ret = cpuhp_invoke_callback(cpu, state, bringup, node);
2378 #endif 1385 #endif
2379 BUG_ON(ret && !bringup); 1386 BUG_ON(ret && !bringup);
2380 return ret; 1387 return ret;
2381 } 1388 }
2382 1389
2383 /* 1390 /*
2384 * Called from __cpuhp_setup_state on a recov 1391 * Called from __cpuhp_setup_state on a recoverable failure.
2385 * 1392 *
2386 * Note: The teardown callbacks for rollback 1393 * Note: The teardown callbacks for rollback are not allowed to fail!
2387 */ 1394 */
2388 static void cpuhp_rollback_install(int failed 1395 static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state,
2389 struct hli 1396 struct hlist_node *node)
2390 { 1397 {
2391 int cpu; 1398 int cpu;
2392 1399
2393 /* Roll back the already executed ste 1400 /* Roll back the already executed steps on the other cpus */
2394 for_each_present_cpu(cpu) { 1401 for_each_present_cpu(cpu) {
2395 struct cpuhp_cpu_state *st = 1402 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2396 int cpustate = st->state; 1403 int cpustate = st->state;
2397 1404
2398 if (cpu >= failedcpu) 1405 if (cpu >= failedcpu)
2399 break; 1406 break;
2400 1407
2401 /* Did we invoke the startup 1408 /* Did we invoke the startup call on that cpu ? */
2402 if (cpustate >= state) 1409 if (cpustate >= state)
2403 cpuhp_issue_call(cpu, 1410 cpuhp_issue_call(cpu, state, false, node);
2404 } 1411 }
2405 } 1412 }
2406 1413
2407 int __cpuhp_state_add_instance_cpuslocked(enu !! 1414 int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
2408 str !! 1415 bool invoke)
2409 boo <<
2410 { 1416 {
2411 struct cpuhp_step *sp; 1417 struct cpuhp_step *sp;
2412 int cpu; 1418 int cpu;
2413 int ret; 1419 int ret;
2414 1420
2415 lockdep_assert_cpus_held(); <<
2416 <<
2417 sp = cpuhp_get_step(state); 1421 sp = cpuhp_get_step(state);
2418 if (sp->multi_instance == false) 1422 if (sp->multi_instance == false)
2419 return -EINVAL; 1423 return -EINVAL;
2420 1424
>> 1425 get_online_cpus();
2421 mutex_lock(&cpuhp_state_mutex); 1426 mutex_lock(&cpuhp_state_mutex);
2422 1427
2423 if (!invoke || !sp->startup.multi) 1428 if (!invoke || !sp->startup.multi)
2424 goto add_node; 1429 goto add_node;
2425 1430
2426 /* 1431 /*
2427 * Try to call the startup callback f 1432 * Try to call the startup callback for each present cpu
2428 * depending on the hotplug state of 1433 * depending on the hotplug state of the cpu.
2429 */ 1434 */
2430 for_each_present_cpu(cpu) { 1435 for_each_present_cpu(cpu) {
2431 struct cpuhp_cpu_state *st = 1436 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2432 int cpustate = st->state; 1437 int cpustate = st->state;
2433 1438
2434 if (cpustate < state) 1439 if (cpustate < state)
2435 continue; 1440 continue;
2436 1441
2437 ret = cpuhp_issue_call(cpu, s 1442 ret = cpuhp_issue_call(cpu, state, true, node);
2438 if (ret) { 1443 if (ret) {
2439 if (sp->teardown.mult 1444 if (sp->teardown.multi)
2440 cpuhp_rollbac 1445 cpuhp_rollback_install(cpu, state, node);
2441 goto unlock; 1446 goto unlock;
2442 } 1447 }
2443 } 1448 }
2444 add_node: 1449 add_node:
2445 ret = 0; 1450 ret = 0;
2446 hlist_add_head(node, &sp->list); 1451 hlist_add_head(node, &sp->list);
2447 unlock: 1452 unlock:
2448 mutex_unlock(&cpuhp_state_mutex); 1453 mutex_unlock(&cpuhp_state_mutex);
2449 return ret; !! 1454 put_online_cpus();
2450 } <<
2451 <<
2452 int __cpuhp_state_add_instance(enum cpuhp_sta <<
2453 bool invoke) <<
2454 { <<
2455 int ret; <<
2456 <<
2457 cpus_read_lock(); <<
2458 ret = __cpuhp_state_add_instance_cpus <<
2459 cpus_read_unlock(); <<
2460 return ret; 1455 return ret;
2461 } 1456 }
2462 EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance) 1457 EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
2463 1458
2464 /** 1459 /**
2465 * __cpuhp_setup_state_cpuslocked - Setup the !! 1460 * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state
2466 * @state: The state to setup 1461 * @state: The state to setup
2467 * @name: Name of the step <<
2468 * @invoke: If true, the startup 1462 * @invoke: If true, the startup function is invoked for cpus where
2469 * cpu state >= @state 1463 * cpu state >= @state
2470 * @startup: startup callback func 1464 * @startup: startup callback function
2471 * @teardown: teardown callback fun 1465 * @teardown: teardown callback function
2472 * @multi_instance: State is set up for m 1466 * @multi_instance: State is set up for multiple instances which get
2473 * added afterwards. 1467 * added afterwards.
2474 * 1468 *
2475 * The caller needs to hold cpus read locked !! 1469 * Returns:
2476 * Return: <<
2477 * On success: 1470 * On success:
2478 * Positive state number if @state is CP !! 1471 * Positive state number if @state is CPUHP_AP_ONLINE_DYN
2479 * 0 for all other states 1472 * 0 for all other states
2480 * On failure: proper (negative) error code 1473 * On failure: proper (negative) error code
2481 */ 1474 */
2482 int __cpuhp_setup_state_cpuslocked(enum cpuhp !! 1475 int __cpuhp_setup_state(enum cpuhp_state state,
2483 const char !! 1476 const char *name, bool invoke,
2484 int (*star !! 1477 int (*startup)(unsigned int cpu),
2485 int (*tear !! 1478 int (*teardown)(unsigned int cpu),
2486 bool multi !! 1479 bool multi_instance)
2487 { 1480 {
2488 int cpu, ret = 0; 1481 int cpu, ret = 0;
2489 bool dynstate; 1482 bool dynstate;
2490 1483
2491 lockdep_assert_cpus_held(); <<
2492 <<
2493 if (cpuhp_cb_check(state) || !name) 1484 if (cpuhp_cb_check(state) || !name)
2494 return -EINVAL; 1485 return -EINVAL;
2495 1486
>> 1487 get_online_cpus();
2496 mutex_lock(&cpuhp_state_mutex); 1488 mutex_lock(&cpuhp_state_mutex);
2497 1489
2498 ret = cpuhp_store_callbacks(state, na 1490 ret = cpuhp_store_callbacks(state, name, startup, teardown,
2499 multi_ins 1491 multi_instance);
2500 1492
2501 dynstate = state == CPUHP_AP_ONLINE_D !! 1493 dynstate = state == CPUHP_AP_ONLINE_DYN;
2502 if (ret > 0 && dynstate) { 1494 if (ret > 0 && dynstate) {
2503 state = ret; 1495 state = ret;
2504 ret = 0; 1496 ret = 0;
2505 } 1497 }
2506 1498
2507 if (ret || !invoke || !startup) 1499 if (ret || !invoke || !startup)
2508 goto out; 1500 goto out;
2509 1501
2510 /* 1502 /*
2511 * Try to call the startup callback f 1503 * Try to call the startup callback for each present cpu
2512 * depending on the hotplug state of 1504 * depending on the hotplug state of the cpu.
2513 */ 1505 */
2514 for_each_present_cpu(cpu) { 1506 for_each_present_cpu(cpu) {
2515 struct cpuhp_cpu_state *st = 1507 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2516 int cpustate = st->state; 1508 int cpustate = st->state;
2517 1509
2518 if (cpustate < state) 1510 if (cpustate < state)
2519 continue; 1511 continue;
2520 1512
2521 ret = cpuhp_issue_call(cpu, s 1513 ret = cpuhp_issue_call(cpu, state, true, NULL);
2522 if (ret) { 1514 if (ret) {
2523 if (teardown) 1515 if (teardown)
2524 cpuhp_rollbac 1516 cpuhp_rollback_install(cpu, state, NULL);
2525 cpuhp_store_callbacks 1517 cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
2526 goto out; 1518 goto out;
2527 } 1519 }
2528 } 1520 }
2529 out: 1521 out:
2530 mutex_unlock(&cpuhp_state_mutex); 1522 mutex_unlock(&cpuhp_state_mutex);
>> 1523 put_online_cpus();
2531 /* 1524 /*
2532 * If the requested state is CPUHP_AP !! 1525 * If the requested state is CPUHP_AP_ONLINE_DYN, return the
2533 * return the dynamically allocated s !! 1526 * dynamically allocated state in case of success.
2534 */ 1527 */
2535 if (!ret && dynstate) 1528 if (!ret && dynstate)
2536 return state; 1529 return state;
2537 return ret; 1530 return ret;
2538 } 1531 }
2539 EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked) <<
2540 <<
2541 int __cpuhp_setup_state(enum cpuhp_state stat <<
2542 const char *name, boo <<
2543 int (*startup)(unsign <<
2544 int (*teardown)(unsig <<
2545 bool multi_instance) <<
2546 { <<
2547 int ret; <<
2548 <<
2549 cpus_read_lock(); <<
2550 ret = __cpuhp_setup_state_cpuslocked( <<
2551 <<
2552 cpus_read_unlock(); <<
2553 return ret; <<
2554 } <<
2555 EXPORT_SYMBOL(__cpuhp_setup_state); 1532 EXPORT_SYMBOL(__cpuhp_setup_state);
2556 1533
2557 int __cpuhp_state_remove_instance(enum cpuhp_ 1534 int __cpuhp_state_remove_instance(enum cpuhp_state state,
2558 struct hlis 1535 struct hlist_node *node, bool invoke)
2559 { 1536 {
2560 struct cpuhp_step *sp = cpuhp_get_ste 1537 struct cpuhp_step *sp = cpuhp_get_step(state);
2561 int cpu; 1538 int cpu;
2562 1539
2563 BUG_ON(cpuhp_cb_check(state)); 1540 BUG_ON(cpuhp_cb_check(state));
2564 1541
2565 if (!sp->multi_instance) 1542 if (!sp->multi_instance)
2566 return -EINVAL; 1543 return -EINVAL;
2567 1544
2568 cpus_read_lock(); !! 1545 get_online_cpus();
2569 mutex_lock(&cpuhp_state_mutex); 1546 mutex_lock(&cpuhp_state_mutex);
2570 1547
2571 if (!invoke || !cpuhp_get_teardown_cb 1548 if (!invoke || !cpuhp_get_teardown_cb(state))
2572 goto remove; 1549 goto remove;
2573 /* 1550 /*
2574 * Call the teardown callback for eac 1551 * Call the teardown callback for each present cpu depending
2575 * on the hotplug state of the cpu. T 1552 * on the hotplug state of the cpu. This function is not
2576 * allowed to fail currently! 1553 * allowed to fail currently!
2577 */ 1554 */
2578 for_each_present_cpu(cpu) { 1555 for_each_present_cpu(cpu) {
2579 struct cpuhp_cpu_state *st = 1556 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2580 int cpustate = st->state; 1557 int cpustate = st->state;
2581 1558
2582 if (cpustate >= state) 1559 if (cpustate >= state)
2583 cpuhp_issue_call(cpu, 1560 cpuhp_issue_call(cpu, state, false, node);
2584 } 1561 }
2585 1562
2586 remove: 1563 remove:
2587 hlist_del(node); 1564 hlist_del(node);
2588 mutex_unlock(&cpuhp_state_mutex); 1565 mutex_unlock(&cpuhp_state_mutex);
2589 cpus_read_unlock(); !! 1566 put_online_cpus();
2590 1567
2591 return 0; 1568 return 0;
2592 } 1569 }
2593 EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instan 1570 EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance);
2594 1571
2595 /** 1572 /**
2596 * __cpuhp_remove_state_cpuslocked - Remove t !! 1573 * __cpuhp_remove_state - Remove the callbacks for an hotplug machine state
2597 * @state: The state to remove 1574 * @state: The state to remove
2598 * @invoke: If true, the teardown functio 1575 * @invoke: If true, the teardown function is invoked for cpus where
2599 * cpu state >= @state 1576 * cpu state >= @state
2600 * 1577 *
2601 * The caller needs to hold cpus read locked <<
2602 * The teardown callback is currently not all 1578 * The teardown callback is currently not allowed to fail. Think
2603 * about module removal! 1579 * about module removal!
2604 */ 1580 */
2605 void __cpuhp_remove_state_cpuslocked(enum cpu !! 1581 void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
2606 { 1582 {
2607 struct cpuhp_step *sp = cpuhp_get_ste 1583 struct cpuhp_step *sp = cpuhp_get_step(state);
2608 int cpu; 1584 int cpu;
2609 1585
2610 BUG_ON(cpuhp_cb_check(state)); 1586 BUG_ON(cpuhp_cb_check(state));
2611 1587
2612 lockdep_assert_cpus_held(); !! 1588 get_online_cpus();
2613 1589
2614 mutex_lock(&cpuhp_state_mutex); 1590 mutex_lock(&cpuhp_state_mutex);
2615 if (sp->multi_instance) { 1591 if (sp->multi_instance) {
2616 WARN(!hlist_empty(&sp->list), 1592 WARN(!hlist_empty(&sp->list),
2617 "Error: Removing state % 1593 "Error: Removing state %d which has instances left.\n",
2618 state); 1594 state);
2619 goto remove; 1595 goto remove;
2620 } 1596 }
2621 1597
2622 if (!invoke || !cpuhp_get_teardown_cb 1598 if (!invoke || !cpuhp_get_teardown_cb(state))
2623 goto remove; 1599 goto remove;
2624 1600
2625 /* 1601 /*
2626 * Call the teardown callback for eac 1602 * Call the teardown callback for each present cpu depending
2627 * on the hotplug state of the cpu. T 1603 * on the hotplug state of the cpu. This function is not
2628 * allowed to fail currently! 1604 * allowed to fail currently!
2629 */ 1605 */
2630 for_each_present_cpu(cpu) { 1606 for_each_present_cpu(cpu) {
2631 struct cpuhp_cpu_state *st = 1607 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2632 int cpustate = st->state; 1608 int cpustate = st->state;
2633 1609
2634 if (cpustate >= state) 1610 if (cpustate >= state)
2635 cpuhp_issue_call(cpu, 1611 cpuhp_issue_call(cpu, state, false, NULL);
2636 } 1612 }
2637 remove: 1613 remove:
2638 cpuhp_store_callbacks(state, NULL, NU 1614 cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
2639 mutex_unlock(&cpuhp_state_mutex); 1615 mutex_unlock(&cpuhp_state_mutex);
2640 } !! 1616 put_online_cpus();
2641 EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked <<
2642 <<
2643 void __cpuhp_remove_state(enum cpuhp_state st <<
2644 { <<
2645 cpus_read_lock(); <<
2646 __cpuhp_remove_state_cpuslocked(state <<
2647 cpus_read_unlock(); <<
2648 } 1617 }
2649 EXPORT_SYMBOL(__cpuhp_remove_state); 1618 EXPORT_SYMBOL(__cpuhp_remove_state);
2650 1619
2651 #ifdef CONFIG_HOTPLUG_SMT <<
2652 static void cpuhp_offline_cpu_device(unsigned <<
2653 { <<
2654 struct device *dev = get_cpu_device(c <<
2655 <<
2656 dev->offline = true; <<
2657 /* Tell user space about the state ch <<
2658 kobject_uevent(&dev->kobj, KOBJ_OFFLI <<
2659 } <<
2660 <<
2661 static void cpuhp_online_cpu_device(unsigned <<
2662 { <<
2663 struct device *dev = get_cpu_device(c <<
2664 <<
2665 dev->offline = false; <<
2666 /* Tell user space about the state ch <<
2667 kobject_uevent(&dev->kobj, KOBJ_ONLIN <<
2668 } <<
2669 <<
2670 int cpuhp_smt_disable(enum cpuhp_smt_control <<
2671 { <<
2672 int cpu, ret = 0; <<
2673 <<
2674 cpu_maps_update_begin(); <<
2675 for_each_online_cpu(cpu) { <<
2676 if (topology_is_primary_threa <<
2677 continue; <<
2678 /* <<
2679 * Disable can be called with <<
2680 * from a higher to lower num <<
2681 */ <<
2682 if (ctrlval == CPU_SMT_ENABLE <<
2683 continue; <<
2684 ret = cpu_down_maps_locked(cp <<
2685 if (ret) <<
2686 break; <<
2687 /* <<
2688 * As this needs to hold the <<
2689 * to call device_offline() b <<
2690 * cpu_down() which takes cpu <<
2691 * needs to be held as this m <<
2692 * abusers of the hotplug mac <<
2693 * <<
2694 * So nothing would update de <<
2695 * leave the sysfs entry stal <<
2696 * smt control has been chang <<
2697 * called under the sysfs hot <<
2698 * serialized against the reg <<
2699 */ <<
2700 cpuhp_offline_cpu_device(cpu) <<
2701 } <<
2702 if (!ret) <<
2703 cpu_smt_control = ctrlval; <<
2704 cpu_maps_update_done(); <<
2705 return ret; <<
2706 } <<
2707 <<
2708 /* Check if the core a CPU belongs to is onli <<
2709 #if !defined(topology_is_core_online) <<
2710 static inline bool topology_is_core_online(un <<
2711 { <<
2712 return true; <<
2713 } <<
2714 #endif <<
2715 <<
2716 int cpuhp_smt_enable(void) <<
2717 { <<
2718 int cpu, ret = 0; <<
2719 <<
2720 cpu_maps_update_begin(); <<
2721 cpu_smt_control = CPU_SMT_ENABLED; <<
2722 for_each_present_cpu(cpu) { <<
2723 /* Skip online CPUs and CPUs <<
2724 if (cpu_online(cpu) || !node_ <<
2725 continue; <<
2726 if (!cpu_smt_thread_allowed(c <<
2727 continue; <<
2728 ret = _cpu_up(cpu, 0, CPUHP_O <<
2729 if (ret) <<
2730 break; <<
2731 /* See comment in cpuhp_smt_d <<
2732 cpuhp_online_cpu_device(cpu); <<
2733 } <<
2734 cpu_maps_update_done(); <<
2735 return ret; <<
2736 } <<
2737 #endif <<
2738 <<
2739 #if defined(CONFIG_SYSFS) && defined(CONFIG_H 1620 #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
2740 static ssize_t state_show(struct device *dev, !! 1621 static ssize_t show_cpuhp_state(struct device *dev,
2741 struct device_attri !! 1622 struct device_attribute *attr, char *buf)
2742 { 1623 {
2743 struct cpuhp_cpu_state *st = per_cpu_ 1624 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2744 1625
2745 return sprintf(buf, "%d\n", st->state 1626 return sprintf(buf, "%d\n", st->state);
2746 } 1627 }
2747 static DEVICE_ATTR_RO(state); !! 1628 static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL);
2748 1629
2749 static ssize_t target_store(struct device *de !! 1630 static ssize_t write_cpuhp_target(struct device *dev,
2750 const char *buf, !! 1631 struct device_attribute *attr,
>> 1632 const char *buf, size_t count)
2751 { 1633 {
2752 struct cpuhp_cpu_state *st = per_cpu_ 1634 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2753 struct cpuhp_step *sp; 1635 struct cpuhp_step *sp;
2754 int target, ret; 1636 int target, ret;
2755 1637
2756 ret = kstrtoint(buf, 10, &target); 1638 ret = kstrtoint(buf, 10, &target);
2757 if (ret) 1639 if (ret)
2758 return ret; 1640 return ret;
2759 1641
2760 #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL 1642 #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL
2761 if (target < CPUHP_OFFLINE || target 1643 if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE)
2762 return -EINVAL; 1644 return -EINVAL;
2763 #else 1645 #else
2764 if (target != CPUHP_OFFLINE && target 1646 if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE)
2765 return -EINVAL; 1647 return -EINVAL;
2766 #endif 1648 #endif
2767 1649
2768 ret = lock_device_hotplug_sysfs(); 1650 ret = lock_device_hotplug_sysfs();
2769 if (ret) 1651 if (ret)
2770 return ret; 1652 return ret;
2771 1653
2772 mutex_lock(&cpuhp_state_mutex); 1654 mutex_lock(&cpuhp_state_mutex);
2773 sp = cpuhp_get_step(target); 1655 sp = cpuhp_get_step(target);
2774 ret = !sp->name || sp->cant_stop ? -E 1656 ret = !sp->name || sp->cant_stop ? -EINVAL : 0;
2775 mutex_unlock(&cpuhp_state_mutex); 1657 mutex_unlock(&cpuhp_state_mutex);
2776 if (ret) 1658 if (ret)
2777 goto out; 1659 goto out;
2778 1660
2779 if (st->state < target) 1661 if (st->state < target)
2780 ret = cpu_up(dev->id, target) !! 1662 ret = do_cpu_up(dev->id, target);
2781 else if (st->state > target) !! 1663 else
2782 ret = cpu_down(dev->id, targe !! 1664 ret = do_cpu_down(dev->id, target);
2783 else if (WARN_ON(st->target != target <<
2784 st->target = target; <<
2785 out: 1665 out:
2786 unlock_device_hotplug(); 1666 unlock_device_hotplug();
2787 return ret ? ret : count; 1667 return ret ? ret : count;
2788 } 1668 }
2789 1669
2790 static ssize_t target_show(struct device *dev !! 1670 static ssize_t show_cpuhp_target(struct device *dev,
2791 struct device_attr !! 1671 struct device_attribute *attr, char *buf)
2792 { 1672 {
2793 struct cpuhp_cpu_state *st = per_cpu_ 1673 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2794 1674
2795 return sprintf(buf, "%d\n", st->targe 1675 return sprintf(buf, "%d\n", st->target);
2796 } 1676 }
2797 static DEVICE_ATTR_RW(target); !! 1677 static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target);
2798 <<
2799 static ssize_t fail_store(struct device *dev, <<
2800 const char *buf, si <<
2801 { <<
2802 struct cpuhp_cpu_state *st = per_cpu_ <<
2803 struct cpuhp_step *sp; <<
2804 int fail, ret; <<
2805 <<
2806 ret = kstrtoint(buf, 10, &fail); <<
2807 if (ret) <<
2808 return ret; <<
2809 <<
2810 if (fail == CPUHP_INVALID) { <<
2811 st->fail = fail; <<
2812 return count; <<
2813 } <<
2814 <<
2815 if (fail < CPUHP_OFFLINE || fail > CP <<
2816 return -EINVAL; <<
2817 <<
2818 /* <<
2819 * Cannot fail STARTING/DYING callbac <<
2820 */ <<
2821 if (cpuhp_is_atomic_state(fail)) <<
2822 return -EINVAL; <<
2823 <<
2824 /* <<
2825 * DEAD callbacks cannot fail... <<
2826 * ... neither can CPUHP_BRINGUP_CPU <<
2827 * triggering STARTING callbacks, a f <<
2828 * hinder rollback. <<
2829 */ <<
2830 if (fail <= CPUHP_BRINGUP_CPU && st-> <<
2831 return -EINVAL; <<
2832 <<
2833 /* <<
2834 * Cannot fail anything that doesn't <<
2835 */ <<
2836 mutex_lock(&cpuhp_state_mutex); <<
2837 sp = cpuhp_get_step(fail); <<
2838 if (!sp->startup.single && !sp->teard <<
2839 ret = -EINVAL; <<
2840 mutex_unlock(&cpuhp_state_mutex); <<
2841 if (ret) <<
2842 return ret; <<
2843 <<
2844 st->fail = fail; <<
2845 <<
2846 return count; <<
2847 } <<
2848 <<
2849 static ssize_t fail_show(struct device *dev, <<
2850 struct device_attrib <<
2851 { <<
2852 struct cpuhp_cpu_state *st = per_cpu_ <<
2853 <<
2854 return sprintf(buf, "%d\n", st->fail) <<
2855 } <<
2856 <<
2857 static DEVICE_ATTR_RW(fail); <<
2858 1678
2859 static struct attribute *cpuhp_cpu_attrs[] = 1679 static struct attribute *cpuhp_cpu_attrs[] = {
2860 &dev_attr_state.attr, 1680 &dev_attr_state.attr,
2861 &dev_attr_target.attr, 1681 &dev_attr_target.attr,
2862 &dev_attr_fail.attr, <<
2863 NULL 1682 NULL
2864 }; 1683 };
2865 1684
2866 static const struct attribute_group cpuhp_cpu !! 1685 static struct attribute_group cpuhp_cpu_attr_group = {
2867 .attrs = cpuhp_cpu_attrs, 1686 .attrs = cpuhp_cpu_attrs,
2868 .name = "hotplug", 1687 .name = "hotplug",
2869 NULL 1688 NULL
2870 }; 1689 };
2871 1690
2872 static ssize_t states_show(struct device *dev !! 1691 static ssize_t show_cpuhp_states(struct device *dev,
2873 struct devic 1692 struct device_attribute *attr, char *buf)
2874 { 1693 {
2875 ssize_t cur, res = 0; 1694 ssize_t cur, res = 0;
2876 int i; 1695 int i;
2877 1696
2878 mutex_lock(&cpuhp_state_mutex); 1697 mutex_lock(&cpuhp_state_mutex);
2879 for (i = CPUHP_OFFLINE; i <= CPUHP_ON 1698 for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) {
2880 struct cpuhp_step *sp = cpuhp 1699 struct cpuhp_step *sp = cpuhp_get_step(i);
2881 1700
2882 if (sp->name) { 1701 if (sp->name) {
2883 cur = sprintf(buf, "% 1702 cur = sprintf(buf, "%3d: %s\n", i, sp->name);
2884 buf += cur; 1703 buf += cur;
2885 res += cur; 1704 res += cur;
2886 } 1705 }
2887 } 1706 }
2888 mutex_unlock(&cpuhp_state_mutex); 1707 mutex_unlock(&cpuhp_state_mutex);
2889 return res; 1708 return res;
2890 } 1709 }
2891 static DEVICE_ATTR_RO(states); !! 1710 static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL);
2892 1711
2893 static struct attribute *cpuhp_cpu_root_attrs 1712 static struct attribute *cpuhp_cpu_root_attrs[] = {
2894 &dev_attr_states.attr, 1713 &dev_attr_states.attr,
2895 NULL 1714 NULL
2896 }; 1715 };
2897 1716
2898 static const struct attribute_group cpuhp_cpu !! 1717 static struct attribute_group cpuhp_cpu_root_attr_group = {
2899 .attrs = cpuhp_cpu_root_attrs, 1718 .attrs = cpuhp_cpu_root_attrs,
2900 .name = "hotplug", 1719 .name = "hotplug",
2901 NULL 1720 NULL
2902 }; 1721 };
2903 1722
2904 #ifdef CONFIG_HOTPLUG_SMT <<
2905 <<
2906 static bool cpu_smt_num_threads_valid(unsigne <<
2907 { <<
2908 if (IS_ENABLED(CONFIG_SMT_NUM_THREADS <<
2909 return threads >= 1 && thread <<
2910 return threads == 1 || threads == cpu <<
2911 } <<
2912 <<
2913 static ssize_t <<
2914 __store_smt_control(struct device *dev, struc <<
2915 const char *buf, size_t c <<
2916 { <<
2917 int ctrlval, ret, num_threads, orig_t <<
2918 bool force_off; <<
2919 <<
2920 if (cpu_smt_control == CPU_SMT_FORCE_ <<
2921 return -EPERM; <<
2922 <<
2923 if (cpu_smt_control == CPU_SMT_NOT_SU <<
2924 return -ENODEV; <<
2925 <<
2926 if (sysfs_streq(buf, "on")) { <<
2927 ctrlval = CPU_SMT_ENABLED; <<
2928 num_threads = cpu_smt_max_thr <<
2929 } else if (sysfs_streq(buf, "off")) { <<
2930 ctrlval = CPU_SMT_DISABLED; <<
2931 num_threads = 1; <<
2932 } else if (sysfs_streq(buf, "forceoff <<
2933 ctrlval = CPU_SMT_FORCE_DISAB <<
2934 num_threads = 1; <<
2935 } else if (kstrtoint(buf, 10, &num_th <<
2936 if (num_threads == 1) <<
2937 ctrlval = CPU_SMT_DIS <<
2938 else if (cpu_smt_num_threads_ <<
2939 ctrlval = CPU_SMT_ENA <<
2940 else <<
2941 return -EINVAL; <<
2942 } else { <<
2943 return -EINVAL; <<
2944 } <<
2945 <<
2946 ret = lock_device_hotplug_sysfs(); <<
2947 if (ret) <<
2948 return ret; <<
2949 <<
2950 orig_threads = cpu_smt_num_threads; <<
2951 cpu_smt_num_threads = num_threads; <<
2952 <<
2953 force_off = ctrlval != cpu_smt_contro <<
2954 <<
2955 if (num_threads > orig_threads) <<
2956 ret = cpuhp_smt_enable(); <<
2957 else if (num_threads < orig_threads | <<
2958 ret = cpuhp_smt_disable(ctrlv <<
2959 <<
2960 unlock_device_hotplug(); <<
2961 return ret ? ret : count; <<
2962 } <<
2963 <<
2964 #else /* !CONFIG_HOTPLUG_SMT */ <<
2965 static ssize_t <<
2966 __store_smt_control(struct device *dev, struc <<
2967 const char *buf, size_t c <<
2968 { <<
2969 return -ENODEV; <<
2970 } <<
2971 #endif /* CONFIG_HOTPLUG_SMT */ <<
2972 <<
2973 static const char *smt_states[] = { <<
2974 [CPU_SMT_ENABLED] = "on <<
2975 [CPU_SMT_DISABLED] = "of <<
2976 [CPU_SMT_FORCE_DISABLED] = "fo <<
2977 [CPU_SMT_NOT_SUPPORTED] = "no <<
2978 [CPU_SMT_NOT_IMPLEMENTED] = "no <<
2979 }; <<
2980 <<
2981 static ssize_t control_show(struct device *de <<
2982 struct device_att <<
2983 { <<
2984 const char *state = smt_states[cpu_sm <<
2985 <<
2986 #ifdef CONFIG_HOTPLUG_SMT <<
2987 /* <<
2988 * If SMT is enabled but not all thre <<
2989 * number of threads. If all threads <<
2990 * show the state name. <<
2991 */ <<
2992 if (cpu_smt_control == CPU_SMT_ENABLE <<
2993 cpu_smt_num_threads != cpu_smt_ma <<
2994 return sysfs_emit(buf, "%d\n" <<
2995 #endif <<
2996 <<
2997 return sysfs_emit(buf, "%s\n", state) <<
2998 } <<
2999 <<
3000 static ssize_t control_store(struct device *d <<
3001 const char *buf, <<
3002 { <<
3003 return __store_smt_control(dev, attr, <<
3004 } <<
3005 static DEVICE_ATTR_RW(control); <<
3006 <<
3007 static ssize_t active_show(struct device *dev <<
3008 struct device_attr <<
3009 { <<
3010 return sysfs_emit(buf, "%d\n", sched_ <<
3011 } <<
3012 static DEVICE_ATTR_RO(active); <<
3013 <<
3014 static struct attribute *cpuhp_smt_attrs[] = <<
3015 &dev_attr_control.attr, <<
3016 &dev_attr_active.attr, <<
3017 NULL <<
3018 }; <<
3019 <<
3020 static const struct attribute_group cpuhp_smt <<
3021 .attrs = cpuhp_smt_attrs, <<
3022 .name = "smt", <<
3023 NULL <<
3024 }; <<
3025 <<
3026 static int __init cpu_smt_sysfs_init(void) <<
3027 { <<
3028 struct device *dev_root; <<
3029 int ret = -ENODEV; <<
3030 <<
3031 dev_root = bus_get_dev_root(&cpu_subs <<
3032 if (dev_root) { <<
3033 ret = sysfs_create_group(&dev <<
3034 put_device(dev_root); <<
3035 } <<
3036 return ret; <<
3037 } <<
3038 <<
3039 static int __init cpuhp_sysfs_init(void) 1723 static int __init cpuhp_sysfs_init(void)
3040 { 1724 {
3041 struct device *dev_root; <<
3042 int cpu, ret; 1725 int cpu, ret;
3043 1726
3044 ret = cpu_smt_sysfs_init(); !! 1727 ret = sysfs_create_group(&cpu_subsys.dev_root->kobj,
>> 1728 &cpuhp_cpu_root_attr_group);
3045 if (ret) 1729 if (ret)
3046 return ret; 1730 return ret;
3047 1731
3048 dev_root = bus_get_dev_root(&cpu_subs <<
3049 if (dev_root) { <<
3050 ret = sysfs_create_group(&dev <<
3051 put_device(dev_root); <<
3052 if (ret) <<
3053 return ret; <<
3054 } <<
3055 <<
3056 for_each_possible_cpu(cpu) { 1732 for_each_possible_cpu(cpu) {
3057 struct device *dev = get_cpu_ 1733 struct device *dev = get_cpu_device(cpu);
3058 1734
3059 if (!dev) 1735 if (!dev)
3060 continue; 1736 continue;
3061 ret = sysfs_create_group(&dev 1737 ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group);
3062 if (ret) 1738 if (ret)
3063 return ret; 1739 return ret;
3064 } 1740 }
3065 return 0; 1741 return 0;
3066 } 1742 }
3067 device_initcall(cpuhp_sysfs_init); 1743 device_initcall(cpuhp_sysfs_init);
3068 #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU !! 1744 #endif
3069 1745
3070 /* 1746 /*
3071 * cpu_bit_bitmap[] is a special, "compressed 1747 * cpu_bit_bitmap[] is a special, "compressed" data structure that
3072 * represents all NR_CPUS bits binary values 1748 * represents all NR_CPUS bits binary values of 1<<nr.
3073 * 1749 *
3074 * It is used by cpumask_of() to get a consta 1750 * It is used by cpumask_of() to get a constant address to a CPU
3075 * mask value that has a single bit set only. 1751 * mask value that has a single bit set only.
3076 */ 1752 */
3077 1753
3078 /* cpu_bit_bitmap[0] is empty - so we can bac 1754 /* cpu_bit_bitmap[0] is empty - so we can back into it */
3079 #define MASK_DECLARE_1(x) [x+1][0] = (1 1755 #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
3080 #define MASK_DECLARE_2(x) MASK_DECLARE_ 1756 #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
3081 #define MASK_DECLARE_4(x) MASK_DECLARE_ 1757 #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
3082 #define MASK_DECLARE_8(x) MASK_DECLARE_ 1758 #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
3083 1759
3084 const unsigned long cpu_bit_bitmap[BITS_PER_L 1760 const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
3085 1761
3086 MASK_DECLARE_8(0), MASK_DECLARE_ 1762 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
3087 MASK_DECLARE_8(16), MASK_DECLARE_ 1763 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
3088 #if BITS_PER_LONG > 32 1764 #if BITS_PER_LONG > 32
3089 MASK_DECLARE_8(32), MASK_DECLARE_ 1765 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
3090 MASK_DECLARE_8(48), MASK_DECLARE_ 1766 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
3091 #endif 1767 #endif
3092 }; 1768 };
3093 EXPORT_SYMBOL_GPL(cpu_bit_bitmap); 1769 EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
3094 1770
3095 const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = 1771 const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
3096 EXPORT_SYMBOL(cpu_all_bits); 1772 EXPORT_SYMBOL(cpu_all_bits);
3097 1773
3098 #ifdef CONFIG_INIT_ALL_POSSIBLE 1774 #ifdef CONFIG_INIT_ALL_POSSIBLE
3099 struct cpumask __cpu_possible_mask __ro_after !! 1775 struct cpumask __cpu_possible_mask __read_mostly
3100 = {CPU_BITS_ALL}; 1776 = {CPU_BITS_ALL};
3101 #else 1777 #else
3102 struct cpumask __cpu_possible_mask __ro_after !! 1778 struct cpumask __cpu_possible_mask __read_mostly;
3103 #endif 1779 #endif
3104 EXPORT_SYMBOL(__cpu_possible_mask); 1780 EXPORT_SYMBOL(__cpu_possible_mask);
3105 1781
3106 struct cpumask __cpu_online_mask __read_mostl 1782 struct cpumask __cpu_online_mask __read_mostly;
3107 EXPORT_SYMBOL(__cpu_online_mask); 1783 EXPORT_SYMBOL(__cpu_online_mask);
3108 1784
3109 struct cpumask __cpu_enabled_mask __read_most <<
3110 EXPORT_SYMBOL(__cpu_enabled_mask); <<
3111 <<
3112 struct cpumask __cpu_present_mask __read_most 1785 struct cpumask __cpu_present_mask __read_mostly;
3113 EXPORT_SYMBOL(__cpu_present_mask); 1786 EXPORT_SYMBOL(__cpu_present_mask);
3114 1787
3115 struct cpumask __cpu_active_mask __read_mostl 1788 struct cpumask __cpu_active_mask __read_mostly;
3116 EXPORT_SYMBOL(__cpu_active_mask); 1789 EXPORT_SYMBOL(__cpu_active_mask);
3117 1790
3118 struct cpumask __cpu_dying_mask __read_mostly <<
3119 EXPORT_SYMBOL(__cpu_dying_mask); <<
3120 <<
3121 atomic_t __num_online_cpus __read_mostly; <<
3122 EXPORT_SYMBOL(__num_online_cpus); <<
3123 <<
3124 void init_cpu_present(const struct cpumask *s 1791 void init_cpu_present(const struct cpumask *src)
3125 { 1792 {
3126 cpumask_copy(&__cpu_present_mask, src 1793 cpumask_copy(&__cpu_present_mask, src);
3127 } 1794 }
3128 1795
3129 void init_cpu_possible(const struct cpumask * 1796 void init_cpu_possible(const struct cpumask *src)
3130 { 1797 {
3131 cpumask_copy(&__cpu_possible_mask, sr 1798 cpumask_copy(&__cpu_possible_mask, src);
3132 } 1799 }
3133 1800
3134 void init_cpu_online(const struct cpumask *sr 1801 void init_cpu_online(const struct cpumask *src)
3135 { 1802 {
3136 cpumask_copy(&__cpu_online_mask, src) 1803 cpumask_copy(&__cpu_online_mask, src);
3137 } 1804 }
3138 1805
3139 void set_cpu_online(unsigned int cpu, bool on <<
3140 { <<
3141 /* <<
3142 * atomic_inc/dec() is required to ha <<
3143 * function by the reboot and kexec c <<
3144 * IPI/NMI broadcasts when shutting d <<
3145 * regular CPU hotplug is properly se <<
3146 * <<
3147 * Note, that the fact that __num_onl <<
3148 * does not protect readers which are <<
3149 * concurrent hotplug operations. <<
3150 */ <<
3151 if (online) { <<
3152 if (!cpumask_test_and_set_cpu <<
3153 atomic_inc(&__num_onl <<
3154 } else { <<
3155 if (cpumask_test_and_clear_cp <<
3156 atomic_dec(&__num_onl <<
3157 } <<
3158 } <<
3159 <<
3160 /* 1806 /*
3161 * Activate the first processor. 1807 * Activate the first processor.
3162 */ 1808 */
3163 void __init boot_cpu_init(void) 1809 void __init boot_cpu_init(void)
3164 { 1810 {
3165 int cpu = smp_processor_id(); 1811 int cpu = smp_processor_id();
3166 1812
3167 /* Mark the boot cpu "present", "onli 1813 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
3168 set_cpu_online(cpu, true); 1814 set_cpu_online(cpu, true);
3169 set_cpu_active(cpu, true); 1815 set_cpu_active(cpu, true);
3170 set_cpu_present(cpu, true); 1816 set_cpu_present(cpu, true);
3171 set_cpu_possible(cpu, true); 1817 set_cpu_possible(cpu, true);
3172 <<
3173 #ifdef CONFIG_SMP <<
3174 __boot_cpu_id = cpu; <<
3175 #endif <<
3176 } 1818 }
3177 1819
3178 /* 1820 /*
3179 * Must be called _AFTER_ setting up the per_ 1821 * Must be called _AFTER_ setting up the per_cpu areas
3180 */ 1822 */
3181 void __init boot_cpu_hotplug_init(void) !! 1823 void __init boot_cpu_state_init(void)
3182 { <<
3183 #ifdef CONFIG_SMP <<
3184 cpumask_set_cpu(smp_processor_id(), & <<
3185 atomic_set(this_cpu_ptr(&cpuhp_state. <<
3186 #endif <<
3187 this_cpu_write(cpuhp_state.state, CPU <<
3188 this_cpu_write(cpuhp_state.target, CP <<
3189 } <<
3190 <<
3191 #ifdef CONFIG_CPU_MITIGATIONS <<
3192 /* <<
3193 * These are used for a global "mitigations=" <<
3194 * optional CPU mitigations. <<
3195 */ <<
3196 enum cpu_mitigations { <<
3197 CPU_MITIGATIONS_OFF, <<
3198 CPU_MITIGATIONS_AUTO, <<
3199 CPU_MITIGATIONS_AUTO_NOSMT, <<
3200 }; <<
3201 <<
3202 static enum cpu_mitigations cpu_mitigations _ <<
3203 <<
3204 static int __init mitigations_parse_cmdline(c <<
3205 { 1824 {
3206 if (!strcmp(arg, "off")) !! 1825 per_cpu_ptr(&cpuhp_state, smp_processor_id())->state = CPUHP_ONLINE;
3207 cpu_mitigations = CPU_MITIGAT <<
3208 else if (!strcmp(arg, "auto")) <<
3209 cpu_mitigations = CPU_MITIGAT <<
3210 else if (!strcmp(arg, "auto,nosmt")) <<
3211 cpu_mitigations = CPU_MITIGAT <<
3212 else <<
3213 pr_crit("Unsupported mitigati <<
3214 arg); <<
3215 <<
3216 return 0; <<
3217 } <<
3218 <<
3219 /* mitigations=off */ <<
3220 bool cpu_mitigations_off(void) <<
3221 { <<
3222 return cpu_mitigations == CPU_MITIGAT <<
3223 } <<
3224 EXPORT_SYMBOL_GPL(cpu_mitigations_off); <<
3225 <<
3226 /* mitigations=auto,nosmt */ <<
3227 bool cpu_mitigations_auto_nosmt(void) <<
3228 { <<
3229 return cpu_mitigations == CPU_MITIGAT <<
3230 } 1826 }
3231 EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt) <<
3232 #else <<
3233 static int __init mitigations_parse_cmdline(c <<
3234 { <<
3235 pr_crit("Kernel compiled without miti <<
3236 return 0; <<
3237 } <<
3238 #endif <<
3239 early_param("mitigations", mitigations_parse_ <<
3240 1827
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