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