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> 6 #include <linux/sched/mm.h>
7 #include <linux/proc_fs.h> 7 #include <linux/proc_fs.h>
8 #include <linux/smp.h> 8 #include <linux/smp.h>
9 #include <linux/init.h> 9 #include <linux/init.h>
10 #include <linux/notifier.h> 10 #include <linux/notifier.h>
11 #include <linux/sched/signal.h> 11 #include <linux/sched/signal.h>
12 #include <linux/sched/hotplug.h> 12 #include <linux/sched/hotplug.h>
13 #include <linux/sched/isolation.h> 13 #include <linux/sched/isolation.h>
14 #include <linux/sched/task.h> 14 #include <linux/sched/task.h>
15 #include <linux/sched/smt.h> 15 #include <linux/sched/smt.h>
16 #include <linux/unistd.h> 16 #include <linux/unistd.h>
17 #include <linux/cpu.h> 17 #include <linux/cpu.h>
18 #include <linux/oom.h> 18 #include <linux/oom.h>
19 #include <linux/rcupdate.h> 19 #include <linux/rcupdate.h>
20 #include <linux/delay.h> 20 #include <linux/delay.h>
21 #include <linux/export.h> 21 #include <linux/export.h>
22 #include <linux/bug.h> 22 #include <linux/bug.h>
23 #include <linux/kthread.h> 23 #include <linux/kthread.h>
24 #include <linux/stop_machine.h> 24 #include <linux/stop_machine.h>
25 #include <linux/mutex.h> 25 #include <linux/mutex.h>
26 #include <linux/gfp.h> 26 #include <linux/gfp.h>
27 #include <linux/suspend.h> 27 #include <linux/suspend.h>
28 #include <linux/lockdep.h> 28 #include <linux/lockdep.h>
29 #include <linux/tick.h> 29 #include <linux/tick.h>
30 #include <linux/irq.h> 30 #include <linux/irq.h>
31 #include <linux/nmi.h> 31 #include <linux/nmi.h>
32 #include <linux/smpboot.h> 32 #include <linux/smpboot.h>
33 #include <linux/relay.h> 33 #include <linux/relay.h>
34 #include <linux/slab.h> 34 #include <linux/slab.h>
35 #include <linux/scs.h> 35 #include <linux/scs.h>
36 #include <linux/percpu-rwsem.h> 36 #include <linux/percpu-rwsem.h>
37 #include <linux/cpuset.h> 37 #include <linux/cpuset.h>
38 #include <linux/random.h> 38 #include <linux/random.h>
39 #include <linux/cc_platform.h> 39 #include <linux/cc_platform.h>
40 40
41 #include <trace/events/power.h> 41 #include <trace/events/power.h>
42 #define CREATE_TRACE_POINTS 42 #define CREATE_TRACE_POINTS
43 #include <trace/events/cpuhp.h> 43 #include <trace/events/cpuhp.h>
44 44
45 #include "smpboot.h" 45 #include "smpboot.h"
46 46
47 /** 47 /**
48 * struct cpuhp_cpu_state - Per cpu hotplug st 48 * struct cpuhp_cpu_state - Per cpu hotplug state storage
49 * @state: The current cpu state 49 * @state: The current cpu state
50 * @target: The target state 50 * @target: The target state
51 * @fail: Current CPU hotplug callback s 51 * @fail: Current CPU hotplug callback state
52 * @thread: Pointer to the hotplug thread 52 * @thread: Pointer to the hotplug thread
53 * @should_run: Thread should execute 53 * @should_run: Thread should execute
54 * @rollback: Perform a rollback 54 * @rollback: Perform a rollback
55 * @single: Single callback invocation 55 * @single: Single callback invocation
56 * @bringup: Single callback bringup or tea 56 * @bringup: Single callback bringup or teardown selector
57 * @node: Remote CPU node; for multi-ins 57 * @node: Remote CPU node; for multi-instance, do a
58 * single entry callback for inst 58 * single entry callback for install/remove
59 * @last: For multi-instance rollback, r 59 * @last: For multi-instance rollback, remember how far we got
60 * @cb_state: The state for a single callbac 60 * @cb_state: The state for a single callback (install/uninstall)
61 * @result: Result of the operation 61 * @result: Result of the operation
62 * @ap_sync_state: State for AP synchroni 62 * @ap_sync_state: State for AP synchronization
63 * @done_up: Signal completion to the issue 63 * @done_up: Signal completion to the issuer of the task for cpu-up
64 * @done_down: Signal completion to the issue 64 * @done_down: Signal completion to the issuer of the task for cpu-down
65 */ 65 */
66 struct cpuhp_cpu_state { 66 struct cpuhp_cpu_state {
67 enum cpuhp_state state; 67 enum cpuhp_state state;
68 enum cpuhp_state target; 68 enum cpuhp_state target;
69 enum cpuhp_state fail; 69 enum cpuhp_state fail;
70 #ifdef CONFIG_SMP 70 #ifdef CONFIG_SMP
71 struct task_struct *thread; 71 struct task_struct *thread;
72 bool should_run; 72 bool should_run;
73 bool rollback; 73 bool rollback;
74 bool single; 74 bool single;
75 bool bringup; 75 bool bringup;
76 struct hlist_node *node; 76 struct hlist_node *node;
77 struct hlist_node *last; 77 struct hlist_node *last;
78 enum cpuhp_state cb_state; 78 enum cpuhp_state cb_state;
79 int result; 79 int result;
80 atomic_t ap_sync_state; 80 atomic_t ap_sync_state;
81 struct completion done_up; 81 struct completion done_up;
82 struct completion done_down; 82 struct completion done_down;
83 #endif 83 #endif
84 }; 84 };
85 85
86 static DEFINE_PER_CPU(struct cpuhp_cpu_state, 86 static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = {
87 .fail = CPUHP_INVALID, 87 .fail = CPUHP_INVALID,
88 }; 88 };
89 89
90 #ifdef CONFIG_SMP 90 #ifdef CONFIG_SMP
91 cpumask_t cpus_booted_once_mask; 91 cpumask_t cpus_booted_once_mask;
92 #endif 92 #endif
93 93
94 #if defined(CONFIG_LOCKDEP) && defined(CONFIG_ 94 #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP)
95 static struct lockdep_map cpuhp_state_up_map = 95 static struct lockdep_map cpuhp_state_up_map =
96 STATIC_LOCKDEP_MAP_INIT("cpuhp_state-u 96 STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map);
97 static struct lockdep_map cpuhp_state_down_map 97 static struct lockdep_map cpuhp_state_down_map =
98 STATIC_LOCKDEP_MAP_INIT("cpuhp_state-d 98 STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map);
99 99
100 100
101 static inline void cpuhp_lock_acquire(bool bri 101 static inline void cpuhp_lock_acquire(bool bringup)
102 { 102 {
103 lock_map_acquire(bringup ? &cpuhp_stat 103 lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
104 } 104 }
105 105
106 static inline void cpuhp_lock_release(bool bri 106 static inline void cpuhp_lock_release(bool bringup)
107 { 107 {
108 lock_map_release(bringup ? &cpuhp_stat 108 lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map);
109 } 109 }
110 #else 110 #else
111 111
112 static inline void cpuhp_lock_acquire(bool bri 112 static inline void cpuhp_lock_acquire(bool bringup) { }
113 static inline void cpuhp_lock_release(bool bri 113 static inline void cpuhp_lock_release(bool bringup) { }
114 114
115 #endif 115 #endif
116 116
117 /** 117 /**
118 * struct cpuhp_step - Hotplug state machine s 118 * struct cpuhp_step - Hotplug state machine step
119 * @name: Name of the step 119 * @name: Name of the step
120 * @startup: Startup function of the step 120 * @startup: Startup function of the step
121 * @teardown: Teardown function of the step 121 * @teardown: Teardown function of the step
122 * @cant_stop: Bringup/teardown can't be stop 122 * @cant_stop: Bringup/teardown can't be stopped at this step
123 * @multi_instance: State has multiple ins 123 * @multi_instance: State has multiple instances which get added afterwards
124 */ 124 */
125 struct cpuhp_step { 125 struct cpuhp_step {
126 const char *name; 126 const char *name;
127 union { 127 union {
128 int (*single)(unsi 128 int (*single)(unsigned int cpu);
129 int (*multi)(unsig 129 int (*multi)(unsigned int cpu,
130 struc 130 struct hlist_node *node);
131 } startup; 131 } startup;
132 union { 132 union {
133 int (*single)(unsi 133 int (*single)(unsigned int cpu);
134 int (*multi)(unsig 134 int (*multi)(unsigned int cpu,
135 struc 135 struct hlist_node *node);
136 } teardown; 136 } teardown;
137 /* private: */ 137 /* private: */
138 struct hlist_head list; 138 struct hlist_head list;
139 /* public: */ 139 /* public: */
140 bool cant_stop; 140 bool cant_stop;
141 bool multi_instance 141 bool multi_instance;
142 }; 142 };
143 143
144 static DEFINE_MUTEX(cpuhp_state_mutex); 144 static DEFINE_MUTEX(cpuhp_state_mutex);
145 static struct cpuhp_step cpuhp_hp_states[]; 145 static struct cpuhp_step cpuhp_hp_states[];
146 146
147 static struct cpuhp_step *cpuhp_get_step(enum 147 static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state)
148 { 148 {
149 return cpuhp_hp_states + state; 149 return cpuhp_hp_states + state;
150 } 150 }
151 151
152 static bool cpuhp_step_empty(bool bringup, str 152 static bool cpuhp_step_empty(bool bringup, struct cpuhp_step *step)
153 { 153 {
154 return bringup ? !step->startup.single 154 return bringup ? !step->startup.single : !step->teardown.single;
155 } 155 }
156 156
157 /** 157 /**
158 * cpuhp_invoke_callback - Invoke the callback 158 * cpuhp_invoke_callback - Invoke the callbacks for a given state
159 * @cpu: The cpu for which the callback 159 * @cpu: The cpu for which the callback should be invoked
160 * @state: The state to do callbacks for 160 * @state: The state to do callbacks for
161 * @bringup: True if the bringup callback s 161 * @bringup: True if the bringup callback should be invoked
162 * @node: For multi-instance, do a singl 162 * @node: For multi-instance, do a single entry callback for install/remove
163 * @lastp: For multi-instance rollback, r 163 * @lastp: For multi-instance rollback, remember how far we got
164 * 164 *
165 * Called from cpu hotplug and from the state 165 * Called from cpu hotplug and from the state register machinery.
166 * 166 *
167 * Return: %0 on success or a negative errno c 167 * Return: %0 on success or a negative errno code
168 */ 168 */
169 static int cpuhp_invoke_callback(unsigned int 169 static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state,
170 bool bringup, 170 bool bringup, struct hlist_node *node,
171 struct hlist_ 171 struct hlist_node **lastp)
172 { 172 {
173 struct cpuhp_cpu_state *st = per_cpu_p 173 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
174 struct cpuhp_step *step = cpuhp_get_st 174 struct cpuhp_step *step = cpuhp_get_step(state);
175 int (*cbm)(unsigned int cpu, struct hl 175 int (*cbm)(unsigned int cpu, struct hlist_node *node);
176 int (*cb)(unsigned int cpu); 176 int (*cb)(unsigned int cpu);
177 int ret, cnt; 177 int ret, cnt;
178 178
179 if (st->fail == state) { 179 if (st->fail == state) {
180 st->fail = CPUHP_INVALID; 180 st->fail = CPUHP_INVALID;
181 return -EAGAIN; 181 return -EAGAIN;
182 } 182 }
183 183
184 if (cpuhp_step_empty(bringup, step)) { 184 if (cpuhp_step_empty(bringup, step)) {
185 WARN_ON_ONCE(1); 185 WARN_ON_ONCE(1);
186 return 0; 186 return 0;
187 } 187 }
188 188
189 if (!step->multi_instance) { 189 if (!step->multi_instance) {
190 WARN_ON_ONCE(lastp && *lastp); 190 WARN_ON_ONCE(lastp && *lastp);
191 cb = bringup ? step->startup.s 191 cb = bringup ? step->startup.single : step->teardown.single;
192 192
193 trace_cpuhp_enter(cpu, st->tar 193 trace_cpuhp_enter(cpu, st->target, state, cb);
194 ret = cb(cpu); 194 ret = cb(cpu);
195 trace_cpuhp_exit(cpu, st->stat 195 trace_cpuhp_exit(cpu, st->state, state, ret);
196 return ret; 196 return ret;
197 } 197 }
198 cbm = bringup ? step->startup.multi : 198 cbm = bringup ? step->startup.multi : step->teardown.multi;
199 199
200 /* Single invocation for instance add/ 200 /* Single invocation for instance add/remove */
201 if (node) { 201 if (node) {
202 WARN_ON_ONCE(lastp && *lastp); 202 WARN_ON_ONCE(lastp && *lastp);
203 trace_cpuhp_multi_enter(cpu, s 203 trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
204 ret = cbm(cpu, node); 204 ret = cbm(cpu, node);
205 trace_cpuhp_exit(cpu, st->stat 205 trace_cpuhp_exit(cpu, st->state, state, ret);
206 return ret; 206 return ret;
207 } 207 }
208 208
209 /* State transition. Invoke on all ins 209 /* State transition. Invoke on all instances */
210 cnt = 0; 210 cnt = 0;
211 hlist_for_each(node, &step->list) { 211 hlist_for_each(node, &step->list) {
212 if (lastp && node == *lastp) 212 if (lastp && node == *lastp)
213 break; 213 break;
214 214
215 trace_cpuhp_multi_enter(cpu, s 215 trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
216 ret = cbm(cpu, node); 216 ret = cbm(cpu, node);
217 trace_cpuhp_exit(cpu, st->stat 217 trace_cpuhp_exit(cpu, st->state, state, ret);
218 if (ret) { 218 if (ret) {
219 if (!lastp) 219 if (!lastp)
220 goto err; 220 goto err;
221 221
222 *lastp = node; 222 *lastp = node;
223 return ret; 223 return ret;
224 } 224 }
225 cnt++; 225 cnt++;
226 } 226 }
227 if (lastp) 227 if (lastp)
228 *lastp = NULL; 228 *lastp = NULL;
229 return 0; 229 return 0;
230 err: 230 err:
231 /* Rollback the instances if one faile 231 /* Rollback the instances if one failed */
232 cbm = !bringup ? step->startup.multi : 232 cbm = !bringup ? step->startup.multi : step->teardown.multi;
233 if (!cbm) 233 if (!cbm)
234 return ret; 234 return ret;
235 235
236 hlist_for_each(node, &step->list) { 236 hlist_for_each(node, &step->list) {
237 if (!cnt--) 237 if (!cnt--)
238 break; 238 break;
239 239
240 trace_cpuhp_multi_enter(cpu, s 240 trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node);
241 ret = cbm(cpu, node); 241 ret = cbm(cpu, node);
242 trace_cpuhp_exit(cpu, st->stat 242 trace_cpuhp_exit(cpu, st->state, state, ret);
243 /* 243 /*
244 * Rollback must not fail, 244 * Rollback must not fail,
245 */ 245 */
246 WARN_ON_ONCE(ret); 246 WARN_ON_ONCE(ret);
247 } 247 }
248 return ret; 248 return ret;
249 } 249 }
250 250
251 #ifdef CONFIG_SMP 251 #ifdef CONFIG_SMP
252 static bool cpuhp_is_ap_state(enum cpuhp_state 252 static bool cpuhp_is_ap_state(enum cpuhp_state state)
253 { 253 {
254 /* 254 /*
255 * The extra check for CPUHP_TEARDOWN_ 255 * The extra check for CPUHP_TEARDOWN_CPU is only for documentation
256 * purposes as that state is handled e 256 * purposes as that state is handled explicitly in cpu_down.
257 */ 257 */
258 return state > CPUHP_BRINGUP_CPU && st 258 return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU;
259 } 259 }
260 260
261 static inline void wait_for_ap_thread(struct c 261 static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
262 { 262 {
263 struct completion *done = bringup ? &s 263 struct completion *done = bringup ? &st->done_up : &st->done_down;
264 wait_for_completion(done); 264 wait_for_completion(done);
265 } 265 }
266 266
267 static inline void complete_ap_thread(struct c 267 static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup)
268 { 268 {
269 struct completion *done = bringup ? &s 269 struct completion *done = bringup ? &st->done_up : &st->done_down;
270 complete(done); 270 complete(done);
271 } 271 }
272 272
273 /* 273 /*
274 * The former STARTING/DYING states, ran with 274 * The former STARTING/DYING states, ran with IRQs disabled and must not fail.
275 */ 275 */
276 static bool cpuhp_is_atomic_state(enum cpuhp_s 276 static bool cpuhp_is_atomic_state(enum cpuhp_state state)
277 { 277 {
278 return CPUHP_AP_IDLE_DEAD <= state && 278 return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE;
279 } 279 }
280 280
281 /* Synchronization state management */ 281 /* Synchronization state management */
282 enum cpuhp_sync_state { 282 enum cpuhp_sync_state {
283 SYNC_STATE_DEAD, 283 SYNC_STATE_DEAD,
284 SYNC_STATE_KICKED, 284 SYNC_STATE_KICKED,
285 SYNC_STATE_SHOULD_DIE, 285 SYNC_STATE_SHOULD_DIE,
286 SYNC_STATE_ALIVE, 286 SYNC_STATE_ALIVE,
287 SYNC_STATE_SHOULD_ONLINE, 287 SYNC_STATE_SHOULD_ONLINE,
288 SYNC_STATE_ONLINE, 288 SYNC_STATE_ONLINE,
289 }; 289 };
290 290
291 #ifdef CONFIG_HOTPLUG_CORE_SYNC 291 #ifdef CONFIG_HOTPLUG_CORE_SYNC
292 /** 292 /**
293 * cpuhp_ap_update_sync_state - Update synchro 293 * cpuhp_ap_update_sync_state - Update synchronization state during bringup/teardown
294 * @state: The synchronization state to s 294 * @state: The synchronization state to set
295 * 295 *
296 * No synchronization point. Just update of th 296 * No synchronization point. Just update of the synchronization state, but implies
297 * a full barrier so that the AP changes are v 297 * a full barrier so that the AP changes are visible before the control CPU proceeds.
298 */ 298 */
299 static inline void cpuhp_ap_update_sync_state( 299 static inline void cpuhp_ap_update_sync_state(enum cpuhp_sync_state state)
300 { 300 {
301 atomic_t *st = this_cpu_ptr(&cpuhp_sta 301 atomic_t *st = this_cpu_ptr(&cpuhp_state.ap_sync_state);
302 302
303 (void)atomic_xchg(st, state); 303 (void)atomic_xchg(st, state);
304 } 304 }
305 305
306 void __weak arch_cpuhp_sync_state_poll(void) { 306 void __weak arch_cpuhp_sync_state_poll(void) { cpu_relax(); }
307 307
308 static bool cpuhp_wait_for_sync_state(unsigned 308 static bool cpuhp_wait_for_sync_state(unsigned int cpu, enum cpuhp_sync_state state,
309 enum cpu 309 enum cpuhp_sync_state next_state)
310 { 310 {
311 atomic_t *st = per_cpu_ptr(&cpuhp_stat 311 atomic_t *st = per_cpu_ptr(&cpuhp_state.ap_sync_state, cpu);
312 ktime_t now, end, start = ktime_get(); 312 ktime_t now, end, start = ktime_get();
313 int sync; 313 int sync;
314 314
315 end = start + 10ULL * NSEC_PER_SEC; 315 end = start + 10ULL * NSEC_PER_SEC;
316 316
317 sync = atomic_read(st); 317 sync = atomic_read(st);
318 while (1) { 318 while (1) {
319 if (sync == state) { 319 if (sync == state) {
320 if (!atomic_try_cmpxch 320 if (!atomic_try_cmpxchg(st, &sync, next_state))
321 continue; 321 continue;
322 return true; 322 return true;
323 } 323 }
324 324
325 now = ktime_get(); 325 now = ktime_get();
326 if (now > end) { 326 if (now > end) {
327 /* Timeout. Leave the 327 /* Timeout. Leave the state unchanged */
328 return false; 328 return false;
329 } else if (now - start < NSEC_ 329 } else if (now - start < NSEC_PER_MSEC) {
330 /* Poll for one millis 330 /* Poll for one millisecond */
331 arch_cpuhp_sync_state_ 331 arch_cpuhp_sync_state_poll();
332 } else { 332 } else {
333 usleep_range(USEC_PER_ 333 usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
334 } 334 }
335 sync = atomic_read(st); 335 sync = atomic_read(st);
336 } 336 }
337 return true; 337 return true;
338 } 338 }
339 #else /* CONFIG_HOTPLUG_CORE_SYNC */ 339 #else /* CONFIG_HOTPLUG_CORE_SYNC */
340 static inline void cpuhp_ap_update_sync_state( 340 static inline void cpuhp_ap_update_sync_state(enum cpuhp_sync_state state) { }
341 #endif /* !CONFIG_HOTPLUG_CORE_SYNC */ 341 #endif /* !CONFIG_HOTPLUG_CORE_SYNC */
342 342
343 #ifdef CONFIG_HOTPLUG_CORE_SYNC_DEAD 343 #ifdef CONFIG_HOTPLUG_CORE_SYNC_DEAD
344 /** 344 /**
345 * cpuhp_ap_report_dead - Update synchronizati 345 * cpuhp_ap_report_dead - Update synchronization state to DEAD
346 * 346 *
347 * No synchronization point. Just update of th 347 * No synchronization point. Just update of the synchronization state.
348 */ 348 */
349 void cpuhp_ap_report_dead(void) 349 void cpuhp_ap_report_dead(void)
350 { 350 {
351 cpuhp_ap_update_sync_state(SYNC_STATE_ 351 cpuhp_ap_update_sync_state(SYNC_STATE_DEAD);
352 } 352 }
353 353
354 void __weak arch_cpuhp_cleanup_dead_cpu(unsign 354 void __weak arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) { }
355 355
356 /* 356 /*
357 * Late CPU shutdown synchronization point. Ca 357 * Late CPU shutdown synchronization point. Cannot use cpuhp_state::done_down
358 * because the AP cannot issue complete() at t 358 * because the AP cannot issue complete() at this stage.
359 */ 359 */
360 static void cpuhp_bp_sync_dead(unsigned int cp 360 static void cpuhp_bp_sync_dead(unsigned int cpu)
361 { 361 {
362 atomic_t *st = per_cpu_ptr(&cpuhp_stat 362 atomic_t *st = per_cpu_ptr(&cpuhp_state.ap_sync_state, cpu);
363 int sync = atomic_read(st); 363 int sync = atomic_read(st);
364 364
365 do { 365 do {
366 /* CPU can have reported dead 366 /* CPU can have reported dead already. Don't overwrite that! */
367 if (sync == SYNC_STATE_DEAD) 367 if (sync == SYNC_STATE_DEAD)
368 break; 368 break;
369 } while (!atomic_try_cmpxchg(st, &sync 369 } while (!atomic_try_cmpxchg(st, &sync, SYNC_STATE_SHOULD_DIE));
370 370
371 if (cpuhp_wait_for_sync_state(cpu, SYN 371 if (cpuhp_wait_for_sync_state(cpu, SYNC_STATE_DEAD, SYNC_STATE_DEAD)) {
372 /* CPU reached dead state. Inv 372 /* CPU reached dead state. Invoke the cleanup function */
373 arch_cpuhp_cleanup_dead_cpu(cp 373 arch_cpuhp_cleanup_dead_cpu(cpu);
374 return; 374 return;
375 } 375 }
376 376
377 /* No further action possible. Emit me 377 /* No further action possible. Emit message and give up. */
378 pr_err("CPU%u failed to report dead st 378 pr_err("CPU%u failed to report dead state\n", cpu);
379 } 379 }
380 #else /* CONFIG_HOTPLUG_CORE_SYNC_DEAD */ 380 #else /* CONFIG_HOTPLUG_CORE_SYNC_DEAD */
381 static inline void cpuhp_bp_sync_dead(unsigned 381 static inline void cpuhp_bp_sync_dead(unsigned int cpu) { }
382 #endif /* !CONFIG_HOTPLUG_CORE_SYNC_DEAD */ 382 #endif /* !CONFIG_HOTPLUG_CORE_SYNC_DEAD */
383 383
384 #ifdef CONFIG_HOTPLUG_CORE_SYNC_FULL 384 #ifdef CONFIG_HOTPLUG_CORE_SYNC_FULL
385 /** 385 /**
386 * cpuhp_ap_sync_alive - Synchronize AP with t 386 * cpuhp_ap_sync_alive - Synchronize AP with the control CPU once it is alive
387 * 387 *
388 * Updates the AP synchronization state to SYN 388 * Updates the AP synchronization state to SYNC_STATE_ALIVE and waits
389 * for the BP to release it. 389 * for the BP to release it.
390 */ 390 */
391 void cpuhp_ap_sync_alive(void) 391 void cpuhp_ap_sync_alive(void)
392 { 392 {
393 atomic_t *st = this_cpu_ptr(&cpuhp_sta 393 atomic_t *st = this_cpu_ptr(&cpuhp_state.ap_sync_state);
394 394
395 cpuhp_ap_update_sync_state(SYNC_STATE_ 395 cpuhp_ap_update_sync_state(SYNC_STATE_ALIVE);
396 396
397 /* Wait for the control CPU to release 397 /* Wait for the control CPU to release it. */
398 while (atomic_read(st) != SYNC_STATE_S 398 while (atomic_read(st) != SYNC_STATE_SHOULD_ONLINE)
399 cpu_relax(); 399 cpu_relax();
400 } 400 }
401 401
402 static bool cpuhp_can_boot_ap(unsigned int cpu 402 static bool cpuhp_can_boot_ap(unsigned int cpu)
403 { 403 {
404 atomic_t *st = per_cpu_ptr(&cpuhp_stat 404 atomic_t *st = per_cpu_ptr(&cpuhp_state.ap_sync_state, cpu);
405 int sync = atomic_read(st); 405 int sync = atomic_read(st);
406 406
407 again: 407 again:
408 switch (sync) { 408 switch (sync) {
409 case SYNC_STATE_DEAD: 409 case SYNC_STATE_DEAD:
410 /* CPU is properly dead */ 410 /* CPU is properly dead */
411 break; 411 break;
412 case SYNC_STATE_KICKED: 412 case SYNC_STATE_KICKED:
413 /* CPU did not come up in prev 413 /* CPU did not come up in previous attempt */
414 break; 414 break;
415 case SYNC_STATE_ALIVE: 415 case SYNC_STATE_ALIVE:
416 /* CPU is stuck cpuhp_ap_sync_ 416 /* CPU is stuck cpuhp_ap_sync_alive(). */
417 break; 417 break;
418 default: 418 default:
419 /* CPU failed to report online 419 /* CPU failed to report online or dead and is in limbo state. */
420 return false; 420 return false;
421 } 421 }
422 422
423 /* Prepare for booting */ 423 /* Prepare for booting */
424 if (!atomic_try_cmpxchg(st, &sync, SYN 424 if (!atomic_try_cmpxchg(st, &sync, SYNC_STATE_KICKED))
425 goto again; 425 goto again;
426 426
427 return true; 427 return true;
428 } 428 }
429 429
430 void __weak arch_cpuhp_cleanup_kick_cpu(unsign 430 void __weak arch_cpuhp_cleanup_kick_cpu(unsigned int cpu) { }
431 431
432 /* 432 /*
433 * Early CPU bringup synchronization point. Ca 433 * Early CPU bringup synchronization point. Cannot use cpuhp_state::done_up
434 * because the AP cannot issue complete() so e 434 * because the AP cannot issue complete() so early in the bringup.
435 */ 435 */
436 static int cpuhp_bp_sync_alive(unsigned int cp 436 static int cpuhp_bp_sync_alive(unsigned int cpu)
437 { 437 {
438 int ret = 0; 438 int ret = 0;
439 439
440 if (!IS_ENABLED(CONFIG_HOTPLUG_CORE_SY 440 if (!IS_ENABLED(CONFIG_HOTPLUG_CORE_SYNC_FULL))
441 return 0; 441 return 0;
442 442
443 if (!cpuhp_wait_for_sync_state(cpu, SY 443 if (!cpuhp_wait_for_sync_state(cpu, SYNC_STATE_ALIVE, SYNC_STATE_SHOULD_ONLINE)) {
444 pr_err("CPU%u failed to report 444 pr_err("CPU%u failed to report alive state\n", cpu);
445 ret = -EIO; 445 ret = -EIO;
446 } 446 }
447 447
448 /* Let the architecture cleanup the ki 448 /* Let the architecture cleanup the kick alive mechanics. */
449 arch_cpuhp_cleanup_kick_cpu(cpu); 449 arch_cpuhp_cleanup_kick_cpu(cpu);
450 return ret; 450 return ret;
451 } 451 }
452 #else /* CONFIG_HOTPLUG_CORE_SYNC_FULL */ 452 #else /* CONFIG_HOTPLUG_CORE_SYNC_FULL */
453 static inline int cpuhp_bp_sync_alive(unsigned 453 static inline int cpuhp_bp_sync_alive(unsigned int cpu) { return 0; }
454 static inline bool cpuhp_can_boot_ap(unsigned 454 static inline bool cpuhp_can_boot_ap(unsigned int cpu) { return true; }
455 #endif /* !CONFIG_HOTPLUG_CORE_SYNC_FULL */ 455 #endif /* !CONFIG_HOTPLUG_CORE_SYNC_FULL */
456 456
457 /* Serializes the updates to cpu_online_mask, 457 /* Serializes the updates to cpu_online_mask, cpu_present_mask */
458 static DEFINE_MUTEX(cpu_add_remove_lock); 458 static DEFINE_MUTEX(cpu_add_remove_lock);
459 bool cpuhp_tasks_frozen; 459 bool cpuhp_tasks_frozen;
460 EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); 460 EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen);
461 461
462 /* 462 /*
463 * The following two APIs (cpu_maps_update_beg 463 * The following two APIs (cpu_maps_update_begin/done) must be used when
464 * attempting to serialize the updates to cpu_ 464 * attempting to serialize the updates to cpu_online_mask & cpu_present_mask.
465 */ 465 */
466 void cpu_maps_update_begin(void) 466 void cpu_maps_update_begin(void)
467 { 467 {
468 mutex_lock(&cpu_add_remove_lock); 468 mutex_lock(&cpu_add_remove_lock);
469 } 469 }
470 470
471 void cpu_maps_update_done(void) 471 void cpu_maps_update_done(void)
472 { 472 {
473 mutex_unlock(&cpu_add_remove_lock); 473 mutex_unlock(&cpu_add_remove_lock);
474 } 474 }
475 475
476 /* 476 /*
477 * If set, cpu_up and cpu_down will return -EB 477 * If set, cpu_up and cpu_down will return -EBUSY and do nothing.
478 * Should always be manipulated under cpu_add_ 478 * Should always be manipulated under cpu_add_remove_lock
479 */ 479 */
480 static int cpu_hotplug_disabled; 480 static int cpu_hotplug_disabled;
481 481
482 #ifdef CONFIG_HOTPLUG_CPU 482 #ifdef CONFIG_HOTPLUG_CPU
483 483
484 DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); 484 DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock);
485 485
486 static bool cpu_hotplug_offline_disabled __ro_ 486 static bool cpu_hotplug_offline_disabled __ro_after_init;
487 487
488 void cpus_read_lock(void) 488 void cpus_read_lock(void)
489 { 489 {
490 percpu_down_read(&cpu_hotplug_lock); 490 percpu_down_read(&cpu_hotplug_lock);
491 } 491 }
492 EXPORT_SYMBOL_GPL(cpus_read_lock); 492 EXPORT_SYMBOL_GPL(cpus_read_lock);
493 493
494 int cpus_read_trylock(void) 494 int cpus_read_trylock(void)
495 { 495 {
496 return percpu_down_read_trylock(&cpu_h 496 return percpu_down_read_trylock(&cpu_hotplug_lock);
497 } 497 }
498 EXPORT_SYMBOL_GPL(cpus_read_trylock); 498 EXPORT_SYMBOL_GPL(cpus_read_trylock);
499 499
500 void cpus_read_unlock(void) 500 void cpus_read_unlock(void)
501 { 501 {
502 percpu_up_read(&cpu_hotplug_lock); 502 percpu_up_read(&cpu_hotplug_lock);
503 } 503 }
504 EXPORT_SYMBOL_GPL(cpus_read_unlock); 504 EXPORT_SYMBOL_GPL(cpus_read_unlock);
505 505
506 void cpus_write_lock(void) 506 void cpus_write_lock(void)
507 { 507 {
508 percpu_down_write(&cpu_hotplug_lock); 508 percpu_down_write(&cpu_hotplug_lock);
509 } 509 }
510 510
511 void cpus_write_unlock(void) 511 void cpus_write_unlock(void)
512 { 512 {
513 percpu_up_write(&cpu_hotplug_lock); 513 percpu_up_write(&cpu_hotplug_lock);
514 } 514 }
515 515
516 void lockdep_assert_cpus_held(void) 516 void lockdep_assert_cpus_held(void)
517 { 517 {
518 /* 518 /*
519 * We can't have hotplug operations be 519 * We can't have hotplug operations before userspace starts running,
520 * and some init codepaths will knowin 520 * and some init codepaths will knowingly not take the hotplug lock.
521 * This is all valid, so mute lockdep 521 * This is all valid, so mute lockdep until it makes sense to report
522 * unheld locks. 522 * unheld locks.
523 */ 523 */
524 if (system_state < SYSTEM_RUNNING) 524 if (system_state < SYSTEM_RUNNING)
525 return; 525 return;
526 526
527 percpu_rwsem_assert_held(&cpu_hotplug_ 527 percpu_rwsem_assert_held(&cpu_hotplug_lock);
528 } 528 }
529 529
530 #ifdef CONFIG_LOCKDEP 530 #ifdef CONFIG_LOCKDEP
531 int lockdep_is_cpus_held(void) 531 int lockdep_is_cpus_held(void)
532 { 532 {
533 return percpu_rwsem_is_held(&cpu_hotpl 533 return percpu_rwsem_is_held(&cpu_hotplug_lock);
534 } 534 }
535 #endif 535 #endif
536 536
537 static void lockdep_acquire_cpus_lock(void) 537 static void lockdep_acquire_cpus_lock(void)
538 { 538 {
539 rwsem_acquire(&cpu_hotplug_lock.dep_ma 539 rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_);
540 } 540 }
541 541
542 static void lockdep_release_cpus_lock(void) 542 static void lockdep_release_cpus_lock(void)
543 { 543 {
544 rwsem_release(&cpu_hotplug_lock.dep_ma 544 rwsem_release(&cpu_hotplug_lock.dep_map, _THIS_IP_);
545 } 545 }
546 546
547 /* Declare CPU offlining not supported */ 547 /* Declare CPU offlining not supported */
548 void cpu_hotplug_disable_offlining(void) 548 void cpu_hotplug_disable_offlining(void)
549 { 549 {
550 cpu_maps_update_begin(); 550 cpu_maps_update_begin();
551 cpu_hotplug_offline_disabled = true; 551 cpu_hotplug_offline_disabled = true;
552 cpu_maps_update_done(); 552 cpu_maps_update_done();
553 } 553 }
554 554
555 /* 555 /*
556 * Wait for currently running CPU hotplug oper 556 * Wait for currently running CPU hotplug operations to complete (if any) and
557 * disable future CPU hotplug (from sysfs). Th 557 * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
558 * the 'cpu_hotplug_disabled' flag. The same l 558 * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the
559 * hotplug path before performing hotplug oper 559 * hotplug path before performing hotplug operations. So acquiring that lock
560 * guarantees mutual exclusion from any curren 560 * guarantees mutual exclusion from any currently running hotplug operations.
561 */ 561 */
562 void cpu_hotplug_disable(void) 562 void cpu_hotplug_disable(void)
563 { 563 {
564 cpu_maps_update_begin(); 564 cpu_maps_update_begin();
565 cpu_hotplug_disabled++; 565 cpu_hotplug_disabled++;
566 cpu_maps_update_done(); 566 cpu_maps_update_done();
567 } 567 }
568 EXPORT_SYMBOL_GPL(cpu_hotplug_disable); 568 EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
569 569
570 static void __cpu_hotplug_enable(void) 570 static void __cpu_hotplug_enable(void)
571 { 571 {
572 if (WARN_ONCE(!cpu_hotplug_disabled, " 572 if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n"))
573 return; 573 return;
574 cpu_hotplug_disabled--; 574 cpu_hotplug_disabled--;
575 } 575 }
576 576
577 void cpu_hotplug_enable(void) 577 void cpu_hotplug_enable(void)
578 { 578 {
579 cpu_maps_update_begin(); 579 cpu_maps_update_begin();
580 __cpu_hotplug_enable(); 580 __cpu_hotplug_enable();
581 cpu_maps_update_done(); 581 cpu_maps_update_done();
582 } 582 }
583 EXPORT_SYMBOL_GPL(cpu_hotplug_enable); 583 EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
584 584
585 #else 585 #else
586 586
587 static void lockdep_acquire_cpus_lock(void) 587 static void lockdep_acquire_cpus_lock(void)
588 { 588 {
589 } 589 }
590 590
591 static void lockdep_release_cpus_lock(void) 591 static void lockdep_release_cpus_lock(void)
592 { 592 {
593 } 593 }
594 594
595 #endif /* CONFIG_HOTPLUG_CPU */ 595 #endif /* CONFIG_HOTPLUG_CPU */
596 596
597 /* 597 /*
598 * Architectures that need SMT-specific errata 598 * Architectures that need SMT-specific errata handling during SMT hotplug
599 * should override this. 599 * should override this.
600 */ 600 */
601 void __weak arch_smt_update(void) { } 601 void __weak arch_smt_update(void) { }
602 602
603 #ifdef CONFIG_HOTPLUG_SMT 603 #ifdef CONFIG_HOTPLUG_SMT
604 604
605 enum cpuhp_smt_control cpu_smt_control __read_ 605 enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED;
606 static unsigned int cpu_smt_max_threads __ro_a 606 static unsigned int cpu_smt_max_threads __ro_after_init;
607 unsigned int cpu_smt_num_threads __read_mostly 607 unsigned int cpu_smt_num_threads __read_mostly = UINT_MAX;
608 608
609 void __init cpu_smt_disable(bool force) 609 void __init cpu_smt_disable(bool force)
610 { 610 {
611 if (!cpu_smt_possible()) 611 if (!cpu_smt_possible())
612 return; 612 return;
613 613
614 if (force) { 614 if (force) {
615 pr_info("SMT: Force disabled\n 615 pr_info("SMT: Force disabled\n");
616 cpu_smt_control = CPU_SMT_FORC 616 cpu_smt_control = CPU_SMT_FORCE_DISABLED;
617 } else { 617 } else {
618 pr_info("SMT: disabled\n"); 618 pr_info("SMT: disabled\n");
619 cpu_smt_control = CPU_SMT_DISA 619 cpu_smt_control = CPU_SMT_DISABLED;
620 } 620 }
621 cpu_smt_num_threads = 1; 621 cpu_smt_num_threads = 1;
622 } 622 }
623 623
624 /* 624 /*
625 * The decision whether SMT is supported can o 625 * The decision whether SMT is supported can only be done after the full
626 * CPU identification. Called from architectur 626 * CPU identification. Called from architecture code.
627 */ 627 */
628 void __init cpu_smt_set_num_threads(unsigned i 628 void __init cpu_smt_set_num_threads(unsigned int num_threads,
629 unsigned i 629 unsigned int max_threads)
630 { 630 {
631 WARN_ON(!num_threads || (num_threads > 631 WARN_ON(!num_threads || (num_threads > max_threads));
632 632
633 if (max_threads == 1) 633 if (max_threads == 1)
634 cpu_smt_control = CPU_SMT_NOT_ 634 cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
635 635
636 cpu_smt_max_threads = max_threads; 636 cpu_smt_max_threads = max_threads;
637 637
638 /* 638 /*
639 * If SMT has been disabled via the ke 639 * If SMT has been disabled via the kernel command line or SMT is
640 * not supported, set cpu_smt_num_thre 640 * not supported, set cpu_smt_num_threads to 1 for consistency.
641 * If enabled, take the architecture r 641 * If enabled, take the architecture requested number of threads
642 * to bring up into account. 642 * to bring up into account.
643 */ 643 */
644 if (cpu_smt_control != CPU_SMT_ENABLED 644 if (cpu_smt_control != CPU_SMT_ENABLED)
645 cpu_smt_num_threads = 1; 645 cpu_smt_num_threads = 1;
646 else if (num_threads < cpu_smt_num_thr 646 else if (num_threads < cpu_smt_num_threads)
647 cpu_smt_num_threads = num_thre 647 cpu_smt_num_threads = num_threads;
648 } 648 }
649 649
650 static int __init smt_cmdline_disable(char *st 650 static int __init smt_cmdline_disable(char *str)
651 { 651 {
652 cpu_smt_disable(str && !strcmp(str, "f 652 cpu_smt_disable(str && !strcmp(str, "force"));
653 return 0; 653 return 0;
654 } 654 }
655 early_param("nosmt", smt_cmdline_disable); 655 early_param("nosmt", smt_cmdline_disable);
656 656
657 /* 657 /*
658 * For Archicture supporting partial SMT state 658 * For Archicture supporting partial SMT states check if the thread is allowed.
659 * Otherwise this has already been checked thr 659 * Otherwise this has already been checked through cpu_smt_max_threads when
660 * setting the SMT level. 660 * setting the SMT level.
661 */ 661 */
662 static inline bool cpu_smt_thread_allowed(unsi 662 static inline bool cpu_smt_thread_allowed(unsigned int cpu)
663 { 663 {
664 #ifdef CONFIG_SMT_NUM_THREADS_DYNAMIC 664 #ifdef CONFIG_SMT_NUM_THREADS_DYNAMIC
665 return topology_smt_thread_allowed(cpu 665 return topology_smt_thread_allowed(cpu);
666 #else 666 #else
667 return true; 667 return true;
668 #endif 668 #endif
669 } 669 }
670 670
671 static inline bool cpu_bootable(unsigned int c 671 static inline bool cpu_bootable(unsigned int cpu)
672 { 672 {
673 if (cpu_smt_control == CPU_SMT_ENABLED 673 if (cpu_smt_control == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
674 return true; 674 return true;
675 675
676 /* All CPUs are bootable if controls a 676 /* All CPUs are bootable if controls are not configured */
677 if (cpu_smt_control == CPU_SMT_NOT_IMP 677 if (cpu_smt_control == CPU_SMT_NOT_IMPLEMENTED)
678 return true; 678 return true;
679 679
680 /* All CPUs are bootable if CPU is not 680 /* All CPUs are bootable if CPU is not SMT capable */
681 if (cpu_smt_control == CPU_SMT_NOT_SUP 681 if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
682 return true; 682 return true;
683 683
684 if (topology_is_primary_thread(cpu)) 684 if (topology_is_primary_thread(cpu))
685 return true; 685 return true;
686 686
687 /* 687 /*
688 * On x86 it's required to boot all lo 688 * On x86 it's required to boot all logical CPUs at least once so
689 * that the init code can get a chance 689 * that the init code can get a chance to set CR4.MCE on each
690 * CPU. Otherwise, a broadcasted MCE o 690 * CPU. Otherwise, a broadcasted MCE observing CR4.MCE=0b on any
691 * core will shutdown the machine. 691 * core will shutdown the machine.
692 */ 692 */
693 return !cpumask_test_cpu(cpu, &cpus_bo 693 return !cpumask_test_cpu(cpu, &cpus_booted_once_mask);
694 } 694 }
695 695
696 /* Returns true if SMT is supported and not fo 696 /* Returns true if SMT is supported and not forcefully (irreversibly) disabled */
697 bool cpu_smt_possible(void) 697 bool cpu_smt_possible(void)
698 { 698 {
699 return cpu_smt_control != CPU_SMT_FORC 699 return cpu_smt_control != CPU_SMT_FORCE_DISABLED &&
700 cpu_smt_control != CPU_SMT_NOT 700 cpu_smt_control != CPU_SMT_NOT_SUPPORTED;
701 } 701 }
702 EXPORT_SYMBOL_GPL(cpu_smt_possible); 702 EXPORT_SYMBOL_GPL(cpu_smt_possible);
703 703
704 #else 704 #else
705 static inline bool cpu_bootable(unsigned int c 705 static inline bool cpu_bootable(unsigned int cpu) { return true; }
706 #endif 706 #endif
707 707
708 static inline enum cpuhp_state 708 static inline enum cpuhp_state
709 cpuhp_set_state(int cpu, struct cpuhp_cpu_stat 709 cpuhp_set_state(int cpu, struct cpuhp_cpu_state *st, enum cpuhp_state target)
710 { 710 {
711 enum cpuhp_state prev_state = st->stat 711 enum cpuhp_state prev_state = st->state;
712 bool bringup = st->state < target; 712 bool bringup = st->state < target;
713 713
714 st->rollback = false; 714 st->rollback = false;
715 st->last = NULL; 715 st->last = NULL;
716 716
717 st->target = target; 717 st->target = target;
718 st->single = false; 718 st->single = false;
719 st->bringup = bringup; 719 st->bringup = bringup;
720 if (cpu_dying(cpu) != !bringup) 720 if (cpu_dying(cpu) != !bringup)
721 set_cpu_dying(cpu, !bringup); 721 set_cpu_dying(cpu, !bringup);
722 722
723 return prev_state; 723 return prev_state;
724 } 724 }
725 725
726 static inline void 726 static inline void
727 cpuhp_reset_state(int cpu, struct cpuhp_cpu_st 727 cpuhp_reset_state(int cpu, struct cpuhp_cpu_state *st,
728 enum cpuhp_state prev_state) 728 enum cpuhp_state prev_state)
729 { 729 {
730 bool bringup = !st->bringup; 730 bool bringup = !st->bringup;
731 731
732 st->target = prev_state; 732 st->target = prev_state;
733 733
734 /* 734 /*
735 * Already rolling back. No need inver 735 * Already rolling back. No need invert the bringup value or to change
736 * the current state. 736 * the current state.
737 */ 737 */
738 if (st->rollback) 738 if (st->rollback)
739 return; 739 return;
740 740
741 st->rollback = true; 741 st->rollback = true;
742 742
743 /* 743 /*
744 * If we have st->last we need to undo 744 * If we have st->last we need to undo partial multi_instance of this
745 * state first. Otherwise start undo a 745 * state first. Otherwise start undo at the previous state.
746 */ 746 */
747 if (!st->last) { 747 if (!st->last) {
748 if (st->bringup) 748 if (st->bringup)
749 st->state--; 749 st->state--;
750 else 750 else
751 st->state++; 751 st->state++;
752 } 752 }
753 753
754 st->bringup = bringup; 754 st->bringup = bringup;
755 if (cpu_dying(cpu) != !bringup) 755 if (cpu_dying(cpu) != !bringup)
756 set_cpu_dying(cpu, !bringup); 756 set_cpu_dying(cpu, !bringup);
757 } 757 }
758 758
759 /* Regular hotplug invocation of the AP hotplu 759 /* Regular hotplug invocation of the AP hotplug thread */
760 static void __cpuhp_kick_ap(struct cpuhp_cpu_s 760 static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st)
761 { 761 {
762 if (!st->single && st->state == st->ta 762 if (!st->single && st->state == st->target)
763 return; 763 return;
764 764
765 st->result = 0; 765 st->result = 0;
766 /* 766 /*
767 * Make sure the above stores are visi 767 * Make sure the above stores are visible before should_run becomes
768 * true. Paired with the mb() above in 768 * true. Paired with the mb() above in cpuhp_thread_fun()
769 */ 769 */
770 smp_mb(); 770 smp_mb();
771 st->should_run = true; 771 st->should_run = true;
772 wake_up_process(st->thread); 772 wake_up_process(st->thread);
773 wait_for_ap_thread(st, st->bringup); 773 wait_for_ap_thread(st, st->bringup);
774 } 774 }
775 775
776 static int cpuhp_kick_ap(int cpu, struct cpuhp 776 static int cpuhp_kick_ap(int cpu, struct cpuhp_cpu_state *st,
777 enum cpuhp_state targ 777 enum cpuhp_state target)
778 { 778 {
779 enum cpuhp_state prev_state; 779 enum cpuhp_state prev_state;
780 int ret; 780 int ret;
781 781
782 prev_state = cpuhp_set_state(cpu, st, 782 prev_state = cpuhp_set_state(cpu, st, target);
783 __cpuhp_kick_ap(st); 783 __cpuhp_kick_ap(st);
784 if ((ret = st->result)) { 784 if ((ret = st->result)) {
785 cpuhp_reset_state(cpu, st, pre 785 cpuhp_reset_state(cpu, st, prev_state);
786 __cpuhp_kick_ap(st); 786 __cpuhp_kick_ap(st);
787 } 787 }
788 788
789 return ret; 789 return ret;
790 } 790 }
791 791
792 static int bringup_wait_for_ap_online(unsigned 792 static int bringup_wait_for_ap_online(unsigned int cpu)
793 { 793 {
794 struct cpuhp_cpu_state *st = per_cpu_p 794 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
795 795
796 /* Wait for the CPU to reach CPUHP_AP_ 796 /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */
797 wait_for_ap_thread(st, true); 797 wait_for_ap_thread(st, true);
798 if (WARN_ON_ONCE((!cpu_online(cpu)))) 798 if (WARN_ON_ONCE((!cpu_online(cpu))))
799 return -ECANCELED; 799 return -ECANCELED;
800 800
801 /* Unpark the hotplug thread of the ta 801 /* Unpark the hotplug thread of the target cpu */
802 kthread_unpark(st->thread); 802 kthread_unpark(st->thread);
803 803
804 /* 804 /*
805 * SMT soft disabling on X86 requires 805 * SMT soft disabling on X86 requires to bring the CPU out of the
806 * BIOS 'wait for SIPI' state in order 806 * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The
807 * CPU marked itself as booted_once in 807 * CPU marked itself as booted_once in notify_cpu_starting() so the
808 * cpu_bootable() check will now retur 808 * cpu_bootable() check will now return false if this is not the
809 * primary sibling. 809 * primary sibling.
810 */ 810 */
811 if (!cpu_bootable(cpu)) 811 if (!cpu_bootable(cpu))
812 return -ECANCELED; 812 return -ECANCELED;
813 return 0; 813 return 0;
814 } 814 }
815 815
816 #ifdef CONFIG_HOTPLUG_SPLIT_STARTUP 816 #ifdef CONFIG_HOTPLUG_SPLIT_STARTUP
817 static int cpuhp_kick_ap_alive(unsigned int cp 817 static int cpuhp_kick_ap_alive(unsigned int cpu)
818 { 818 {
819 if (!cpuhp_can_boot_ap(cpu)) 819 if (!cpuhp_can_boot_ap(cpu))
820 return -EAGAIN; 820 return -EAGAIN;
821 821
822 return arch_cpuhp_kick_ap_alive(cpu, i 822 return arch_cpuhp_kick_ap_alive(cpu, idle_thread_get(cpu));
823 } 823 }
824 824
825 static int cpuhp_bringup_ap(unsigned int cpu) 825 static int cpuhp_bringup_ap(unsigned int cpu)
826 { 826 {
827 struct cpuhp_cpu_state *st = per_cpu_p 827 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
828 int ret; 828 int ret;
829 829
830 /* 830 /*
831 * Some architectures have to walk the 831 * Some architectures have to walk the irq descriptors to
832 * setup the vector space for the cpu 832 * setup the vector space for the cpu which comes online.
833 * Prevent irq alloc/free across the b 833 * Prevent irq alloc/free across the bringup.
834 */ 834 */
835 irq_lock_sparse(); 835 irq_lock_sparse();
836 836
837 ret = cpuhp_bp_sync_alive(cpu); 837 ret = cpuhp_bp_sync_alive(cpu);
838 if (ret) 838 if (ret)
839 goto out_unlock; 839 goto out_unlock;
840 840
841 ret = bringup_wait_for_ap_online(cpu); 841 ret = bringup_wait_for_ap_online(cpu);
842 if (ret) 842 if (ret)
843 goto out_unlock; 843 goto out_unlock;
844 844
845 irq_unlock_sparse(); 845 irq_unlock_sparse();
846 846
847 if (st->target <= CPUHP_AP_ONLINE_IDLE 847 if (st->target <= CPUHP_AP_ONLINE_IDLE)
848 return 0; 848 return 0;
849 849
850 return cpuhp_kick_ap(cpu, st, st->targ 850 return cpuhp_kick_ap(cpu, st, st->target);
851 851
852 out_unlock: 852 out_unlock:
853 irq_unlock_sparse(); 853 irq_unlock_sparse();
854 return ret; 854 return ret;
855 } 855 }
856 #else 856 #else
857 static int bringup_cpu(unsigned int cpu) 857 static int bringup_cpu(unsigned int cpu)
858 { 858 {
859 struct cpuhp_cpu_state *st = per_cpu_p 859 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
860 struct task_struct *idle = idle_thread 860 struct task_struct *idle = idle_thread_get(cpu);
861 int ret; 861 int ret;
862 862
863 if (!cpuhp_can_boot_ap(cpu)) 863 if (!cpuhp_can_boot_ap(cpu))
864 return -EAGAIN; 864 return -EAGAIN;
865 865
866 /* 866 /*
867 * Some architectures have to walk the 867 * Some architectures have to walk the irq descriptors to
868 * setup the vector space for the cpu 868 * setup the vector space for the cpu which comes online.
869 * 869 *
870 * Prevent irq alloc/free across the b 870 * Prevent irq alloc/free across the bringup by acquiring the
871 * sparse irq lock. Hold it until the 871 * sparse irq lock. Hold it until the upcoming CPU completes the
872 * startup in cpuhp_online_idle() whic 872 * startup in cpuhp_online_idle() which allows to avoid
873 * intermediate synchronization points 873 * intermediate synchronization points in the architecture code.
874 */ 874 */
875 irq_lock_sparse(); 875 irq_lock_sparse();
876 876
877 ret = __cpu_up(cpu, idle); 877 ret = __cpu_up(cpu, idle);
878 if (ret) 878 if (ret)
879 goto out_unlock; 879 goto out_unlock;
880 880
881 ret = cpuhp_bp_sync_alive(cpu); 881 ret = cpuhp_bp_sync_alive(cpu);
882 if (ret) 882 if (ret)
883 goto out_unlock; 883 goto out_unlock;
884 884
885 ret = bringup_wait_for_ap_online(cpu); 885 ret = bringup_wait_for_ap_online(cpu);
886 if (ret) 886 if (ret)
887 goto out_unlock; 887 goto out_unlock;
888 888
889 irq_unlock_sparse(); 889 irq_unlock_sparse();
890 890
891 if (st->target <= CPUHP_AP_ONLINE_IDLE 891 if (st->target <= CPUHP_AP_ONLINE_IDLE)
892 return 0; 892 return 0;
893 893
894 return cpuhp_kick_ap(cpu, st, st->targ 894 return cpuhp_kick_ap(cpu, st, st->target);
895 895
896 out_unlock: 896 out_unlock:
897 irq_unlock_sparse(); 897 irq_unlock_sparse();
898 return ret; 898 return ret;
899 } 899 }
900 #endif 900 #endif
901 901
902 static int finish_cpu(unsigned int cpu) 902 static int finish_cpu(unsigned int cpu)
903 { 903 {
904 struct task_struct *idle = idle_thread 904 struct task_struct *idle = idle_thread_get(cpu);
905 struct mm_struct *mm = idle->active_mm 905 struct mm_struct *mm = idle->active_mm;
906 906
907 /* 907 /*
908 * idle_task_exit() will have switched 908 * idle_task_exit() will have switched to &init_mm, now
909 * clean up any remaining active_mm st 909 * clean up any remaining active_mm state.
910 */ 910 */
911 if (mm != &init_mm) 911 if (mm != &init_mm)
912 idle->active_mm = &init_mm; 912 idle->active_mm = &init_mm;
913 mmdrop_lazy_tlb(mm); 913 mmdrop_lazy_tlb(mm);
914 return 0; 914 return 0;
915 } 915 }
916 916
917 /* 917 /*
918 * Hotplug state machine related functions 918 * Hotplug state machine related functions
919 */ 919 */
920 920
921 /* 921 /*
922 * Get the next state to run. Empty ones will 922 * Get the next state to run. Empty ones will be skipped. Returns true if a
923 * state must be run. 923 * state must be run.
924 * 924 *
925 * st->state will be modified ahead of time, t 925 * st->state will be modified ahead of time, to match state_to_run, as if it
926 * has already ran. 926 * has already ran.
927 */ 927 */
928 static bool cpuhp_next_state(bool bringup, 928 static bool cpuhp_next_state(bool bringup,
929 enum cpuhp_state 929 enum cpuhp_state *state_to_run,
930 struct cpuhp_cpu_ 930 struct cpuhp_cpu_state *st,
931 enum cpuhp_state 931 enum cpuhp_state target)
932 { 932 {
933 do { 933 do {
934 if (bringup) { 934 if (bringup) {
935 if (st->state >= targe 935 if (st->state >= target)
936 return false; 936 return false;
937 937
938 *state_to_run = ++st-> 938 *state_to_run = ++st->state;
939 } else { 939 } else {
940 if (st->state <= targe 940 if (st->state <= target)
941 return false; 941 return false;
942 942
943 *state_to_run = st->st 943 *state_to_run = st->state--;
944 } 944 }
945 945
946 if (!cpuhp_step_empty(bringup, 946 if (!cpuhp_step_empty(bringup, cpuhp_get_step(*state_to_run)))
947 break; 947 break;
948 } while (true); 948 } while (true);
949 949
950 return true; 950 return true;
951 } 951 }
952 952
953 static int __cpuhp_invoke_callback_range(bool 953 static int __cpuhp_invoke_callback_range(bool bringup,
954 unsig 954 unsigned int cpu,
955 struc 955 struct cpuhp_cpu_state *st,
956 enum 956 enum cpuhp_state target,
957 bool 957 bool nofail)
958 { 958 {
959 enum cpuhp_state state; 959 enum cpuhp_state state;
960 int ret = 0; 960 int ret = 0;
961 961
962 while (cpuhp_next_state(bringup, &stat 962 while (cpuhp_next_state(bringup, &state, st, target)) {
963 int err; 963 int err;
964 964
965 err = cpuhp_invoke_callback(cp 965 err = cpuhp_invoke_callback(cpu, state, bringup, NULL, NULL);
966 if (!err) 966 if (!err)
967 continue; 967 continue;
968 968
969 if (nofail) { 969 if (nofail) {
970 pr_warn("CPU %u %s sta 970 pr_warn("CPU %u %s state %s (%d) failed (%d)\n",
971 cpu, bringup ? 971 cpu, bringup ? "UP" : "DOWN",
972 cpuhp_get_step 972 cpuhp_get_step(st->state)->name,
973 st->state, err 973 st->state, err);
974 ret = -1; 974 ret = -1;
975 } else { 975 } else {
976 ret = err; 976 ret = err;
977 break; 977 break;
978 } 978 }
979 } 979 }
980 980
981 return ret; 981 return ret;
982 } 982 }
983 983
984 static inline int cpuhp_invoke_callback_range( 984 static inline int cpuhp_invoke_callback_range(bool bringup,
985 985 unsigned int cpu,
986 986 struct cpuhp_cpu_state *st,
987 987 enum cpuhp_state target)
988 { 988 {
989 return __cpuhp_invoke_callback_range(b 989 return __cpuhp_invoke_callback_range(bringup, cpu, st, target, false);
990 } 990 }
991 991
992 static inline void cpuhp_invoke_callback_range 992 static inline void cpuhp_invoke_callback_range_nofail(bool bringup,
993 993 unsigned int cpu,
994 994 struct cpuhp_cpu_state *st,
995 995 enum cpuhp_state target)
996 { 996 {
997 __cpuhp_invoke_callback_range(bringup, 997 __cpuhp_invoke_callback_range(bringup, cpu, st, target, true);
998 } 998 }
999 999
1000 static inline bool can_rollback_cpu(struct cp 1000 static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st)
1001 { 1001 {
1002 if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) 1002 if (IS_ENABLED(CONFIG_HOTPLUG_CPU))
1003 return true; 1003 return true;
1004 /* 1004 /*
1005 * When CPU hotplug is disabled, then 1005 * When CPU hotplug is disabled, then taking the CPU down is not
1006 * possible because takedown_cpu() an 1006 * possible because takedown_cpu() and the architecture and
1007 * subsystem specific mechanisms are 1007 * subsystem specific mechanisms are not available. So the CPU
1008 * which would be completely unplugge 1008 * which would be completely unplugged again needs to stay around
1009 * in the current state. 1009 * in the current state.
1010 */ 1010 */
1011 return st->state <= CPUHP_BRINGUP_CPU 1011 return st->state <= CPUHP_BRINGUP_CPU;
1012 } 1012 }
1013 1013
1014 static int cpuhp_up_callbacks(unsigned int cp 1014 static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
1015 enum cpuhp_stat 1015 enum cpuhp_state target)
1016 { 1016 {
1017 enum cpuhp_state prev_state = st->sta 1017 enum cpuhp_state prev_state = st->state;
1018 int ret = 0; 1018 int ret = 0;
1019 1019
1020 ret = cpuhp_invoke_callback_range(tru 1020 ret = cpuhp_invoke_callback_range(true, cpu, st, target);
1021 if (ret) { 1021 if (ret) {
1022 pr_debug("CPU UP failed (%d) 1022 pr_debug("CPU UP failed (%d) CPU %u state %s (%d)\n",
1023 ret, cpu, cpuhp_get_ 1023 ret, cpu, cpuhp_get_step(st->state)->name,
1024 st->state); 1024 st->state);
1025 1025
1026 cpuhp_reset_state(cpu, st, pr 1026 cpuhp_reset_state(cpu, st, prev_state);
1027 if (can_rollback_cpu(st)) 1027 if (can_rollback_cpu(st))
1028 WARN_ON(cpuhp_invoke_ 1028 WARN_ON(cpuhp_invoke_callback_range(false, cpu, st,
1029 1029 prev_state));
1030 } 1030 }
1031 return ret; 1031 return ret;
1032 } 1032 }
1033 1033
1034 /* 1034 /*
1035 * The cpu hotplug threads manage the bringup 1035 * The cpu hotplug threads manage the bringup and teardown of the cpus
1036 */ 1036 */
1037 static int cpuhp_should_run(unsigned int cpu) 1037 static int cpuhp_should_run(unsigned int cpu)
1038 { 1038 {
1039 struct cpuhp_cpu_state *st = this_cpu 1039 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1040 1040
1041 return st->should_run; 1041 return st->should_run;
1042 } 1042 }
1043 1043
1044 /* 1044 /*
1045 * Execute teardown/startup callbacks on the 1045 * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke
1046 * callbacks when a state gets [un]installed 1046 * callbacks when a state gets [un]installed at runtime.
1047 * 1047 *
1048 * Each invocation of this function by the sm 1048 * Each invocation of this function by the smpboot thread does a single AP
1049 * state callback. 1049 * state callback.
1050 * 1050 *
1051 * It has 3 modes of operation: 1051 * It has 3 modes of operation:
1052 * - single: runs st->cb_state 1052 * - single: runs st->cb_state
1053 * - up: runs ++st->state, while st->sta 1053 * - up: runs ++st->state, while st->state < st->target
1054 * - down: runs st->state--, while st->sta 1054 * - down: runs st->state--, while st->state > st->target
1055 * 1055 *
1056 * When complete or on error, should_run is c 1056 * When complete or on error, should_run is cleared and the completion is fired.
1057 */ 1057 */
1058 static void cpuhp_thread_fun(unsigned int cpu 1058 static void cpuhp_thread_fun(unsigned int cpu)
1059 { 1059 {
1060 struct cpuhp_cpu_state *st = this_cpu 1060 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1061 bool bringup = st->bringup; 1061 bool bringup = st->bringup;
1062 enum cpuhp_state state; 1062 enum cpuhp_state state;
1063 1063
1064 if (WARN_ON_ONCE(!st->should_run)) 1064 if (WARN_ON_ONCE(!st->should_run))
1065 return; 1065 return;
1066 1066
1067 /* 1067 /*
1068 * ACQUIRE for the cpuhp_should_run() 1068 * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures
1069 * that if we see ->should_run we als 1069 * that if we see ->should_run we also see the rest of the state.
1070 */ 1070 */
1071 smp_mb(); 1071 smp_mb();
1072 1072
1073 /* 1073 /*
1074 * The BP holds the hotplug lock, but 1074 * The BP holds the hotplug lock, but we're now running on the AP,
1075 * ensure that anybody asserting the 1075 * ensure that anybody asserting the lock is held, will actually find
1076 * it so. 1076 * it so.
1077 */ 1077 */
1078 lockdep_acquire_cpus_lock(); 1078 lockdep_acquire_cpus_lock();
1079 cpuhp_lock_acquire(bringup); 1079 cpuhp_lock_acquire(bringup);
1080 1080
1081 if (st->single) { 1081 if (st->single) {
1082 state = st->cb_state; 1082 state = st->cb_state;
1083 st->should_run = false; 1083 st->should_run = false;
1084 } else { 1084 } else {
1085 st->should_run = cpuhp_next_s 1085 st->should_run = cpuhp_next_state(bringup, &state, st, st->target);
1086 if (!st->should_run) 1086 if (!st->should_run)
1087 goto end; 1087 goto end;
1088 } 1088 }
1089 1089
1090 WARN_ON_ONCE(!cpuhp_is_ap_state(state 1090 WARN_ON_ONCE(!cpuhp_is_ap_state(state));
1091 1091
1092 if (cpuhp_is_atomic_state(state)) { 1092 if (cpuhp_is_atomic_state(state)) {
1093 local_irq_disable(); 1093 local_irq_disable();
1094 st->result = cpuhp_invoke_cal 1094 st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
1095 local_irq_enable(); 1095 local_irq_enable();
1096 1096
1097 /* 1097 /*
1098 * STARTING/DYING must not fa 1098 * STARTING/DYING must not fail!
1099 */ 1099 */
1100 WARN_ON_ONCE(st->result); 1100 WARN_ON_ONCE(st->result);
1101 } else { 1101 } else {
1102 st->result = cpuhp_invoke_cal 1102 st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last);
1103 } 1103 }
1104 1104
1105 if (st->result) { 1105 if (st->result) {
1106 /* 1106 /*
1107 * If we fail on a rollback, 1107 * If we fail on a rollback, we're up a creek without no
1108 * paddle, no way forward, no 1108 * paddle, no way forward, no way back. We loose, thanks for
1109 * playing. 1109 * playing.
1110 */ 1110 */
1111 WARN_ON_ONCE(st->rollback); 1111 WARN_ON_ONCE(st->rollback);
1112 st->should_run = false; 1112 st->should_run = false;
1113 } 1113 }
1114 1114
1115 end: 1115 end:
1116 cpuhp_lock_release(bringup); 1116 cpuhp_lock_release(bringup);
1117 lockdep_release_cpus_lock(); 1117 lockdep_release_cpus_lock();
1118 1118
1119 if (!st->should_run) 1119 if (!st->should_run)
1120 complete_ap_thread(st, bringu 1120 complete_ap_thread(st, bringup);
1121 } 1121 }
1122 1122
1123 /* Invoke a single callback on a remote cpu * 1123 /* Invoke a single callback on a remote cpu */
1124 static int 1124 static int
1125 cpuhp_invoke_ap_callback(int cpu, enum cpuhp_ 1125 cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup,
1126 struct hlist_node *n 1126 struct hlist_node *node)
1127 { 1127 {
1128 struct cpuhp_cpu_state *st = per_cpu_ 1128 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1129 int ret; 1129 int ret;
1130 1130
1131 if (!cpu_online(cpu)) 1131 if (!cpu_online(cpu))
1132 return 0; 1132 return 0;
1133 1133
1134 cpuhp_lock_acquire(false); 1134 cpuhp_lock_acquire(false);
1135 cpuhp_lock_release(false); 1135 cpuhp_lock_release(false);
1136 1136
1137 cpuhp_lock_acquire(true); 1137 cpuhp_lock_acquire(true);
1138 cpuhp_lock_release(true); 1138 cpuhp_lock_release(true);
1139 1139
1140 /* 1140 /*
1141 * If we are up and running, use the 1141 * If we are up and running, use the hotplug thread. For early calls
1142 * we invoke the thread function dire 1142 * we invoke the thread function directly.
1143 */ 1143 */
1144 if (!st->thread) 1144 if (!st->thread)
1145 return cpuhp_invoke_callback( 1145 return cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
1146 1146
1147 st->rollback = false; 1147 st->rollback = false;
1148 st->last = NULL; 1148 st->last = NULL;
1149 1149
1150 st->node = node; 1150 st->node = node;
1151 st->bringup = bringup; 1151 st->bringup = bringup;
1152 st->cb_state = state; 1152 st->cb_state = state;
1153 st->single = true; 1153 st->single = true;
1154 1154
1155 __cpuhp_kick_ap(st); 1155 __cpuhp_kick_ap(st);
1156 1156
1157 /* 1157 /*
1158 * If we failed and did a partial, do 1158 * If we failed and did a partial, do a rollback.
1159 */ 1159 */
1160 if ((ret = st->result) && st->last) { 1160 if ((ret = st->result) && st->last) {
1161 st->rollback = true; 1161 st->rollback = true;
1162 st->bringup = !bringup; 1162 st->bringup = !bringup;
1163 1163
1164 __cpuhp_kick_ap(st); 1164 __cpuhp_kick_ap(st);
1165 } 1165 }
1166 1166
1167 /* 1167 /*
1168 * Clean up the leftovers so the next 1168 * Clean up the leftovers so the next hotplug operation wont use stale
1169 * data. 1169 * data.
1170 */ 1170 */
1171 st->node = st->last = NULL; 1171 st->node = st->last = NULL;
1172 return ret; 1172 return ret;
1173 } 1173 }
1174 1174
1175 static int cpuhp_kick_ap_work(unsigned int cp 1175 static int cpuhp_kick_ap_work(unsigned int cpu)
1176 { 1176 {
1177 struct cpuhp_cpu_state *st = per_cpu_ 1177 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1178 enum cpuhp_state prev_state = st->sta 1178 enum cpuhp_state prev_state = st->state;
1179 int ret; 1179 int ret;
1180 1180
1181 cpuhp_lock_acquire(false); 1181 cpuhp_lock_acquire(false);
1182 cpuhp_lock_release(false); 1182 cpuhp_lock_release(false);
1183 1183
1184 cpuhp_lock_acquire(true); 1184 cpuhp_lock_acquire(true);
1185 cpuhp_lock_release(true); 1185 cpuhp_lock_release(true);
1186 1186
1187 trace_cpuhp_enter(cpu, st->target, pr 1187 trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work);
1188 ret = cpuhp_kick_ap(cpu, st, st->targ 1188 ret = cpuhp_kick_ap(cpu, st, st->target);
1189 trace_cpuhp_exit(cpu, st->state, prev 1189 trace_cpuhp_exit(cpu, st->state, prev_state, ret);
1190 1190
1191 return ret; 1191 return ret;
1192 } 1192 }
1193 1193
1194 static struct smp_hotplug_thread cpuhp_thread 1194 static struct smp_hotplug_thread cpuhp_threads = {
1195 .store = &cpuhp_stat 1195 .store = &cpuhp_state.thread,
1196 .thread_should_run = cpuhp_shoul 1196 .thread_should_run = cpuhp_should_run,
1197 .thread_fn = cpuhp_threa 1197 .thread_fn = cpuhp_thread_fun,
1198 .thread_comm = "cpuhp/%u", 1198 .thread_comm = "cpuhp/%u",
1199 .selfparking = true, 1199 .selfparking = true,
1200 }; 1200 };
1201 1201
1202 static __init void cpuhp_init_state(void) 1202 static __init void cpuhp_init_state(void)
1203 { 1203 {
1204 struct cpuhp_cpu_state *st; 1204 struct cpuhp_cpu_state *st;
1205 int cpu; 1205 int cpu;
1206 1206
1207 for_each_possible_cpu(cpu) { 1207 for_each_possible_cpu(cpu) {
1208 st = per_cpu_ptr(&cpuhp_state 1208 st = per_cpu_ptr(&cpuhp_state, cpu);
1209 init_completion(&st->done_up) 1209 init_completion(&st->done_up);
1210 init_completion(&st->done_dow 1210 init_completion(&st->done_down);
1211 } 1211 }
1212 } 1212 }
1213 1213
1214 void __init cpuhp_threads_init(void) 1214 void __init cpuhp_threads_init(void)
1215 { 1215 {
1216 cpuhp_init_state(); 1216 cpuhp_init_state();
1217 BUG_ON(smpboot_register_percpu_thread 1217 BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads));
1218 kthread_unpark(this_cpu_read(cpuhp_st 1218 kthread_unpark(this_cpu_read(cpuhp_state.thread));
1219 } 1219 }
1220 1220
1221 #ifdef CONFIG_HOTPLUG_CPU 1221 #ifdef CONFIG_HOTPLUG_CPU
1222 #ifndef arch_clear_mm_cpumask_cpu 1222 #ifndef arch_clear_mm_cpumask_cpu
1223 #define arch_clear_mm_cpumask_cpu(cpu, mm) cp 1223 #define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm))
1224 #endif 1224 #endif
1225 1225
1226 /** 1226 /**
1227 * clear_tasks_mm_cpumask - Safely clear task 1227 * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
1228 * @cpu: a CPU id 1228 * @cpu: a CPU id
1229 * 1229 *
1230 * This function walks all processes, finds a 1230 * This function walks all processes, finds a valid mm struct for each one and
1231 * then clears a corresponding bit in mm's cp 1231 * then clears a corresponding bit in mm's cpumask. While this all sounds
1232 * trivial, there are various non-obvious cor 1232 * trivial, there are various non-obvious corner cases, which this function
1233 * tries to solve in a safe manner. 1233 * tries to solve in a safe manner.
1234 * 1234 *
1235 * Also note that the function uses a somewha 1235 * Also note that the function uses a somewhat relaxed locking scheme, so it may
1236 * be called only for an already offlined CPU 1236 * be called only for an already offlined CPU.
1237 */ 1237 */
1238 void clear_tasks_mm_cpumask(int cpu) 1238 void clear_tasks_mm_cpumask(int cpu)
1239 { 1239 {
1240 struct task_struct *p; 1240 struct task_struct *p;
1241 1241
1242 /* 1242 /*
1243 * This function is called after the 1243 * This function is called after the cpu is taken down and marked
1244 * offline, so its not like new tasks 1244 * offline, so its not like new tasks will ever get this cpu set in
1245 * their mm mask. -- Peter Zijlstra 1245 * their mm mask. -- Peter Zijlstra
1246 * Thus, we may use rcu_read_lock() h 1246 * Thus, we may use rcu_read_lock() here, instead of grabbing
1247 * full-fledged tasklist_lock. 1247 * full-fledged tasklist_lock.
1248 */ 1248 */
1249 WARN_ON(cpu_online(cpu)); 1249 WARN_ON(cpu_online(cpu));
1250 rcu_read_lock(); 1250 rcu_read_lock();
1251 for_each_process(p) { 1251 for_each_process(p) {
1252 struct task_struct *t; 1252 struct task_struct *t;
1253 1253
1254 /* 1254 /*
1255 * Main thread might exit, bu 1255 * Main thread might exit, but other threads may still have
1256 * a valid mm. Find one. 1256 * a valid mm. Find one.
1257 */ 1257 */
1258 t = find_lock_task_mm(p); 1258 t = find_lock_task_mm(p);
1259 if (!t) 1259 if (!t)
1260 continue; 1260 continue;
1261 arch_clear_mm_cpumask_cpu(cpu 1261 arch_clear_mm_cpumask_cpu(cpu, t->mm);
1262 task_unlock(t); 1262 task_unlock(t);
1263 } 1263 }
1264 rcu_read_unlock(); 1264 rcu_read_unlock();
1265 } 1265 }
1266 1266
1267 /* Take this CPU down. */ 1267 /* Take this CPU down. */
1268 static int take_cpu_down(void *_param) 1268 static int take_cpu_down(void *_param)
1269 { 1269 {
1270 struct cpuhp_cpu_state *st = this_cpu 1270 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1271 enum cpuhp_state target = max((int)st 1271 enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE);
1272 int err, cpu = smp_processor_id(); 1272 int err, cpu = smp_processor_id();
1273 1273
1274 /* Ensure this CPU doesn't handle any 1274 /* Ensure this CPU doesn't handle any more interrupts. */
1275 err = __cpu_disable(); 1275 err = __cpu_disable();
1276 if (err < 0) 1276 if (err < 0)
1277 return err; 1277 return err;
1278 1278
1279 /* 1279 /*
1280 * Must be called from CPUHP_TEARDOWN 1280 * Must be called from CPUHP_TEARDOWN_CPU, which means, as we are going
1281 * down, that the current state is CP 1281 * down, that the current state is CPUHP_TEARDOWN_CPU - 1.
1282 */ 1282 */
1283 WARN_ON(st->state != (CPUHP_TEARDOWN_ 1283 WARN_ON(st->state != (CPUHP_TEARDOWN_CPU - 1));
1284 1284
1285 /* 1285 /*
1286 * Invoke the former CPU_DYING callba 1286 * Invoke the former CPU_DYING callbacks. DYING must not fail!
1287 */ 1287 */
1288 cpuhp_invoke_callback_range_nofail(fa 1288 cpuhp_invoke_callback_range_nofail(false, cpu, st, target);
1289 1289
1290 /* Park the stopper thread */ 1290 /* Park the stopper thread */
1291 stop_machine_park(cpu); 1291 stop_machine_park(cpu);
1292 return 0; 1292 return 0;
1293 } 1293 }
1294 1294
1295 static int takedown_cpu(unsigned int cpu) 1295 static int takedown_cpu(unsigned int cpu)
1296 { 1296 {
1297 struct cpuhp_cpu_state *st = per_cpu_ 1297 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1298 int err; 1298 int err;
1299 1299
1300 /* Park the smpboot threads */ 1300 /* Park the smpboot threads */
1301 kthread_park(st->thread); 1301 kthread_park(st->thread);
1302 1302
1303 /* 1303 /*
1304 * Prevent irq alloc/free while the d 1304 * Prevent irq alloc/free while the dying cpu reorganizes the
1305 * interrupt affinities. 1305 * interrupt affinities.
1306 */ 1306 */
1307 irq_lock_sparse(); 1307 irq_lock_sparse();
1308 1308
1309 /* 1309 /*
1310 * So now all preempt/rcu users must 1310 * So now all preempt/rcu users must observe !cpu_active().
1311 */ 1311 */
1312 err = stop_machine_cpuslocked(take_cp 1312 err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
1313 if (err) { 1313 if (err) {
1314 /* CPU refused to die */ 1314 /* CPU refused to die */
1315 irq_unlock_sparse(); 1315 irq_unlock_sparse();
1316 /* Unpark the hotplug thread 1316 /* Unpark the hotplug thread so we can rollback there */
1317 kthread_unpark(st->thread); 1317 kthread_unpark(st->thread);
1318 return err; 1318 return err;
1319 } 1319 }
1320 BUG_ON(cpu_online(cpu)); 1320 BUG_ON(cpu_online(cpu));
1321 1321
1322 /* 1322 /*
1323 * The teardown callback for CPUHP_AP 1323 * The teardown callback for CPUHP_AP_SCHED_STARTING will have removed
1324 * all runnable tasks from the CPU, t 1324 * all runnable tasks from the CPU, there's only the idle task left now
1325 * that the migration thread is done 1325 * that the migration thread is done doing the stop_machine thing.
1326 * 1326 *
1327 * Wait for the stop thread to go awa 1327 * Wait for the stop thread to go away.
1328 */ 1328 */
1329 wait_for_ap_thread(st, false); 1329 wait_for_ap_thread(st, false);
1330 BUG_ON(st->state != CPUHP_AP_IDLE_DEA 1330 BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
1331 1331
1332 /* Interrupts are moved away from the 1332 /* Interrupts are moved away from the dying cpu, reenable alloc/free */
1333 irq_unlock_sparse(); 1333 irq_unlock_sparse();
1334 1334
1335 hotplug_cpu__broadcast_tick_pull(cpu) 1335 hotplug_cpu__broadcast_tick_pull(cpu);
1336 /* This actually kills the CPU. */ 1336 /* This actually kills the CPU. */
1337 __cpu_die(cpu); 1337 __cpu_die(cpu);
1338 1338
1339 cpuhp_bp_sync_dead(cpu); 1339 cpuhp_bp_sync_dead(cpu);
1340 1340
1341 tick_cleanup_dead_cpu(cpu); 1341 tick_cleanup_dead_cpu(cpu);
1342 1342
1343 /* 1343 /*
1344 * Callbacks must be re-integrated ri 1344 * Callbacks must be re-integrated right away to the RCU state machine.
1345 * Otherwise an RCU callback could bl 1345 * Otherwise an RCU callback could block a further teardown function
1346 * waiting for its completion. 1346 * waiting for its completion.
1347 */ 1347 */
1348 rcutree_migrate_callbacks(cpu); 1348 rcutree_migrate_callbacks(cpu);
1349 1349
1350 return 0; 1350 return 0;
1351 } 1351 }
1352 1352
1353 static void cpuhp_complete_idle_dead(void *ar 1353 static void cpuhp_complete_idle_dead(void *arg)
1354 { 1354 {
1355 struct cpuhp_cpu_state *st = arg; 1355 struct cpuhp_cpu_state *st = arg;
1356 1356
1357 complete_ap_thread(st, false); 1357 complete_ap_thread(st, false);
1358 } 1358 }
1359 1359
1360 void cpuhp_report_idle_dead(void) 1360 void cpuhp_report_idle_dead(void)
1361 { 1361 {
1362 struct cpuhp_cpu_state *st = this_cpu 1362 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1363 1363
1364 BUG_ON(st->state != CPUHP_AP_OFFLINE) 1364 BUG_ON(st->state != CPUHP_AP_OFFLINE);
1365 tick_assert_timekeeping_handover(); 1365 tick_assert_timekeeping_handover();
1366 rcutree_report_cpu_dead(); 1366 rcutree_report_cpu_dead();
1367 st->state = CPUHP_AP_IDLE_DEAD; 1367 st->state = CPUHP_AP_IDLE_DEAD;
1368 /* 1368 /*
1369 * We cannot call complete after rcut 1369 * We cannot call complete after rcutree_report_cpu_dead() so we delegate it
1370 * to an online cpu. 1370 * to an online cpu.
1371 */ 1371 */
1372 smp_call_function_single(cpumask_firs 1372 smp_call_function_single(cpumask_first(cpu_online_mask),
1373 cpuhp_comple 1373 cpuhp_complete_idle_dead, st, 0);
1374 } 1374 }
1375 1375
1376 static int cpuhp_down_callbacks(unsigned int 1376 static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
1377 enum cpuhp_st 1377 enum cpuhp_state target)
1378 { 1378 {
1379 enum cpuhp_state prev_state = st->sta 1379 enum cpuhp_state prev_state = st->state;
1380 int ret = 0; 1380 int ret = 0;
1381 1381
1382 ret = cpuhp_invoke_callback_range(fal 1382 ret = cpuhp_invoke_callback_range(false, cpu, st, target);
1383 if (ret) { 1383 if (ret) {
1384 pr_debug("CPU DOWN failed (%d 1384 pr_debug("CPU DOWN failed (%d) CPU %u state %s (%d)\n",
1385 ret, cpu, cpuhp_get_ 1385 ret, cpu, cpuhp_get_step(st->state)->name,
1386 st->state); 1386 st->state);
1387 1387
1388 cpuhp_reset_state(cpu, st, pr 1388 cpuhp_reset_state(cpu, st, prev_state);
1389 1389
1390 if (st->state < prev_state) 1390 if (st->state < prev_state)
1391 WARN_ON(cpuhp_invoke_ 1391 WARN_ON(cpuhp_invoke_callback_range(true, cpu, st,
1392 1392 prev_state));
1393 } 1393 }
1394 1394
1395 return ret; 1395 return ret;
1396 } 1396 }
1397 1397
1398 /* Requires cpu_add_remove_lock to be held */ 1398 /* Requires cpu_add_remove_lock to be held */
1399 static int __ref _cpu_down(unsigned int cpu, 1399 static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
1400 enum cpuhp_state t 1400 enum cpuhp_state target)
1401 { 1401 {
1402 struct cpuhp_cpu_state *st = per_cpu_ 1402 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1403 int prev_state, ret = 0; 1403 int prev_state, ret = 0;
1404 1404
1405 if (num_online_cpus() == 1) 1405 if (num_online_cpus() == 1)
1406 return -EBUSY; 1406 return -EBUSY;
1407 1407
1408 if (!cpu_present(cpu)) 1408 if (!cpu_present(cpu))
1409 return -EINVAL; 1409 return -EINVAL;
1410 1410
1411 cpus_write_lock(); 1411 cpus_write_lock();
1412 1412
1413 cpuhp_tasks_frozen = tasks_frozen; 1413 cpuhp_tasks_frozen = tasks_frozen;
1414 1414
1415 prev_state = cpuhp_set_state(cpu, st, 1415 prev_state = cpuhp_set_state(cpu, st, target);
1416 /* 1416 /*
1417 * If the current CPU state is in the 1417 * If the current CPU state is in the range of the AP hotplug thread,
1418 * then we need to kick the thread. 1418 * then we need to kick the thread.
1419 */ 1419 */
1420 if (st->state > CPUHP_TEARDOWN_CPU) { 1420 if (st->state > CPUHP_TEARDOWN_CPU) {
1421 st->target = max((int)target, 1421 st->target = max((int)target, CPUHP_TEARDOWN_CPU);
1422 ret = cpuhp_kick_ap_work(cpu) 1422 ret = cpuhp_kick_ap_work(cpu);
1423 /* 1423 /*
1424 * The AP side has done the e 1424 * The AP side has done the error rollback already. Just
1425 * return the error code.. 1425 * return the error code..
1426 */ 1426 */
1427 if (ret) 1427 if (ret)
1428 goto out; 1428 goto out;
1429 1429
1430 /* 1430 /*
1431 * We might have stopped stil 1431 * We might have stopped still in the range of the AP hotplug
1432 * thread. Nothing to do anym 1432 * thread. Nothing to do anymore.
1433 */ 1433 */
1434 if (st->state > CPUHP_TEARDOW 1434 if (st->state > CPUHP_TEARDOWN_CPU)
1435 goto out; 1435 goto out;
1436 1436
1437 st->target = target; 1437 st->target = target;
1438 } 1438 }
1439 /* 1439 /*
1440 * The AP brought itself down to CPUH 1440 * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need
1441 * to do the further cleanups. 1441 * to do the further cleanups.
1442 */ 1442 */
1443 ret = cpuhp_down_callbacks(cpu, st, t 1443 ret = cpuhp_down_callbacks(cpu, st, target);
1444 if (ret && st->state < prev_state) { 1444 if (ret && st->state < prev_state) {
1445 if (st->state == CPUHP_TEARDO 1445 if (st->state == CPUHP_TEARDOWN_CPU) {
1446 cpuhp_reset_state(cpu 1446 cpuhp_reset_state(cpu, st, prev_state);
1447 __cpuhp_kick_ap(st); 1447 __cpuhp_kick_ap(st);
1448 } else { 1448 } else {
1449 WARN(1, "DEAD callbac 1449 WARN(1, "DEAD callback error for CPU%d", cpu);
1450 } 1450 }
1451 } 1451 }
1452 1452
1453 out: 1453 out:
1454 cpus_write_unlock(); 1454 cpus_write_unlock();
1455 /* 1455 /*
1456 * Do post unplug cleanup. This is st 1456 * Do post unplug cleanup. This is still protected against
1457 * concurrent CPU hotplug via cpu_add 1457 * concurrent CPU hotplug via cpu_add_remove_lock.
1458 */ 1458 */
1459 lockup_detector_cleanup(); 1459 lockup_detector_cleanup();
1460 arch_smt_update(); 1460 arch_smt_update();
1461 return ret; 1461 return ret;
1462 } 1462 }
1463 1463
1464 struct cpu_down_work { 1464 struct cpu_down_work {
1465 unsigned int cpu; 1465 unsigned int cpu;
1466 enum cpuhp_state target; 1466 enum cpuhp_state target;
1467 }; 1467 };
1468 1468
1469 static long __cpu_down_maps_locked(void *arg) 1469 static long __cpu_down_maps_locked(void *arg)
1470 { 1470 {
1471 struct cpu_down_work *work = arg; 1471 struct cpu_down_work *work = arg;
1472 1472
1473 return _cpu_down(work->cpu, 0, work-> 1473 return _cpu_down(work->cpu, 0, work->target);
1474 } 1474 }
1475 1475
1476 static int cpu_down_maps_locked(unsigned int 1476 static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target)
1477 { 1477 {
1478 struct cpu_down_work work = { .cpu = 1478 struct cpu_down_work work = { .cpu = cpu, .target = target, };
1479 1479
1480 /* 1480 /*
1481 * If the platform does not support h 1481 * If the platform does not support hotplug, report it explicitly to
1482 * differentiate it from a transient 1482 * differentiate it from a transient offlining failure.
1483 */ 1483 */
1484 if (cpu_hotplug_offline_disabled) 1484 if (cpu_hotplug_offline_disabled)
1485 return -EOPNOTSUPP; 1485 return -EOPNOTSUPP;
1486 if (cpu_hotplug_disabled) 1486 if (cpu_hotplug_disabled)
1487 return -EBUSY; 1487 return -EBUSY;
1488 1488
1489 /* 1489 /*
1490 * Ensure that the control task does 1490 * Ensure that the control task does not run on the to be offlined
1491 * CPU to prevent a deadlock against 1491 * CPU to prevent a deadlock against cfs_b->period_timer.
1492 * Also keep at least one housekeepin 1492 * Also keep at least one housekeeping cpu onlined to avoid generating
1493 * an empty sched_domain span. 1493 * an empty sched_domain span.
1494 */ 1494 */
1495 for_each_cpu_and(cpu, cpu_online_mask 1495 for_each_cpu_and(cpu, cpu_online_mask, housekeeping_cpumask(HK_TYPE_DOMAIN)) {
1496 if (cpu != work.cpu) 1496 if (cpu != work.cpu)
1497 return work_on_cpu(cp 1497 return work_on_cpu(cpu, __cpu_down_maps_locked, &work);
1498 } 1498 }
1499 return -EBUSY; 1499 return -EBUSY;
1500 } 1500 }
1501 1501
1502 static int cpu_down(unsigned int cpu, enum cp 1502 static int cpu_down(unsigned int cpu, enum cpuhp_state target)
1503 { 1503 {
1504 int err; 1504 int err;
1505 1505
1506 cpu_maps_update_begin(); 1506 cpu_maps_update_begin();
1507 err = cpu_down_maps_locked(cpu, targe 1507 err = cpu_down_maps_locked(cpu, target);
1508 cpu_maps_update_done(); 1508 cpu_maps_update_done();
1509 return err; 1509 return err;
1510 } 1510 }
1511 1511
1512 /** 1512 /**
1513 * cpu_device_down - Bring down a cpu device 1513 * cpu_device_down - Bring down a cpu device
1514 * @dev: Pointer to the cpu device to offline 1514 * @dev: Pointer to the cpu device to offline
1515 * 1515 *
1516 * This function is meant to be used by devic 1516 * This function is meant to be used by device core cpu subsystem only.
1517 * 1517 *
1518 * Other subsystems should use remove_cpu() i 1518 * Other subsystems should use remove_cpu() instead.
1519 * 1519 *
1520 * Return: %0 on success or a negative errno 1520 * Return: %0 on success or a negative errno code
1521 */ 1521 */
1522 int cpu_device_down(struct device *dev) 1522 int cpu_device_down(struct device *dev)
1523 { 1523 {
1524 return cpu_down(dev->id, CPUHP_OFFLIN 1524 return cpu_down(dev->id, CPUHP_OFFLINE);
1525 } 1525 }
1526 1526
1527 int remove_cpu(unsigned int cpu) 1527 int remove_cpu(unsigned int cpu)
1528 { 1528 {
1529 int ret; 1529 int ret;
1530 1530
1531 lock_device_hotplug(); 1531 lock_device_hotplug();
1532 ret = device_offline(get_cpu_device(c 1532 ret = device_offline(get_cpu_device(cpu));
1533 unlock_device_hotplug(); 1533 unlock_device_hotplug();
1534 1534
1535 return ret; 1535 return ret;
1536 } 1536 }
1537 EXPORT_SYMBOL_GPL(remove_cpu); 1537 EXPORT_SYMBOL_GPL(remove_cpu);
1538 1538
1539 void smp_shutdown_nonboot_cpus(unsigned int p 1539 void smp_shutdown_nonboot_cpus(unsigned int primary_cpu)
1540 { 1540 {
1541 unsigned int cpu; 1541 unsigned int cpu;
1542 int error; 1542 int error;
1543 1543
1544 cpu_maps_update_begin(); 1544 cpu_maps_update_begin();
1545 1545
1546 /* 1546 /*
1547 * Make certain the cpu I'm about to 1547 * Make certain the cpu I'm about to reboot on is online.
1548 * 1548 *
1549 * This is inline to what migrate_to_ 1549 * This is inline to what migrate_to_reboot_cpu() already do.
1550 */ 1550 */
1551 if (!cpu_online(primary_cpu)) 1551 if (!cpu_online(primary_cpu))
1552 primary_cpu = cpumask_first(c 1552 primary_cpu = cpumask_first(cpu_online_mask);
1553 1553
1554 for_each_online_cpu(cpu) { 1554 for_each_online_cpu(cpu) {
1555 if (cpu == primary_cpu) 1555 if (cpu == primary_cpu)
1556 continue; 1556 continue;
1557 1557
1558 error = cpu_down_maps_locked( 1558 error = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
1559 if (error) { 1559 if (error) {
1560 pr_err("Failed to off 1560 pr_err("Failed to offline CPU%d - error=%d",
1561 cpu, error); 1561 cpu, error);
1562 break; 1562 break;
1563 } 1563 }
1564 } 1564 }
1565 1565
1566 /* 1566 /*
1567 * Ensure all but the reboot CPU are 1567 * Ensure all but the reboot CPU are offline.
1568 */ 1568 */
1569 BUG_ON(num_online_cpus() > 1); 1569 BUG_ON(num_online_cpus() > 1);
1570 1570
1571 /* 1571 /*
1572 * Make sure the CPUs won't be enable 1572 * Make sure the CPUs won't be enabled by someone else after this
1573 * point. Kexec will reboot to a new 1573 * point. Kexec will reboot to a new kernel shortly resetting
1574 * everything along the way. 1574 * everything along the way.
1575 */ 1575 */
1576 cpu_hotplug_disabled++; 1576 cpu_hotplug_disabled++;
1577 1577
1578 cpu_maps_update_done(); 1578 cpu_maps_update_done();
1579 } 1579 }
1580 1580
1581 #else 1581 #else
1582 #define takedown_cpu NULL 1582 #define takedown_cpu NULL
1583 #endif /*CONFIG_HOTPLUG_CPU*/ 1583 #endif /*CONFIG_HOTPLUG_CPU*/
1584 1584
1585 /** 1585 /**
1586 * notify_cpu_starting(cpu) - Invoke the call 1586 * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU
1587 * @cpu: cpu that just started 1587 * @cpu: cpu that just started
1588 * 1588 *
1589 * It must be called by the arch code on the 1589 * It must be called by the arch code on the new cpu, before the new cpu
1590 * enables interrupts and before the "boot" c 1590 * enables interrupts and before the "boot" cpu returns from __cpu_up().
1591 */ 1591 */
1592 void notify_cpu_starting(unsigned int cpu) 1592 void notify_cpu_starting(unsigned int cpu)
1593 { 1593 {
1594 struct cpuhp_cpu_state *st = per_cpu_ 1594 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1595 enum cpuhp_state target = min((int)st 1595 enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE);
1596 1596
1597 rcutree_report_cpu_starting(cpu); 1597 rcutree_report_cpu_starting(cpu); /* Enables RCU usage on this CPU. */
1598 cpumask_set_cpu(cpu, &cpus_booted_onc 1598 cpumask_set_cpu(cpu, &cpus_booted_once_mask);
1599 1599
1600 /* 1600 /*
1601 * STARTING must not fail! 1601 * STARTING must not fail!
1602 */ 1602 */
1603 cpuhp_invoke_callback_range_nofail(tr 1603 cpuhp_invoke_callback_range_nofail(true, cpu, st, target);
1604 } 1604 }
1605 1605
1606 /* 1606 /*
1607 * Called from the idle task. Wake up the con 1607 * Called from the idle task. Wake up the controlling task which brings the
1608 * hotplug thread of the upcoming CPU up and 1608 * hotplug thread of the upcoming CPU up and then delegates the rest of the
1609 * online bringup to the hotplug thread. 1609 * online bringup to the hotplug thread.
1610 */ 1610 */
1611 void cpuhp_online_idle(enum cpuhp_state state 1611 void cpuhp_online_idle(enum cpuhp_state state)
1612 { 1612 {
1613 struct cpuhp_cpu_state *st = this_cpu 1613 struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state);
1614 1614
1615 /* Happens for the boot cpu */ 1615 /* Happens for the boot cpu */
1616 if (state != CPUHP_AP_ONLINE_IDLE) 1616 if (state != CPUHP_AP_ONLINE_IDLE)
1617 return; 1617 return;
1618 1618
1619 cpuhp_ap_update_sync_state(SYNC_STATE 1619 cpuhp_ap_update_sync_state(SYNC_STATE_ONLINE);
1620 1620
1621 /* 1621 /*
1622 * Unpark the stopper thread before w 1622 * Unpark the stopper thread before we start the idle loop (and start
1623 * scheduling); this ensures the stop 1623 * scheduling); this ensures the stopper task is always available.
1624 */ 1624 */
1625 stop_machine_unpark(smp_processor_id( 1625 stop_machine_unpark(smp_processor_id());
1626 1626
1627 st->state = CPUHP_AP_ONLINE_IDLE; 1627 st->state = CPUHP_AP_ONLINE_IDLE;
1628 complete_ap_thread(st, true); 1628 complete_ap_thread(st, true);
1629 } 1629 }
1630 1630
1631 /* Requires cpu_add_remove_lock to be held */ 1631 /* Requires cpu_add_remove_lock to be held */
1632 static int _cpu_up(unsigned int cpu, int task 1632 static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target)
1633 { 1633 {
1634 struct cpuhp_cpu_state *st = per_cpu_ 1634 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1635 struct task_struct *idle; 1635 struct task_struct *idle;
1636 int ret = 0; 1636 int ret = 0;
1637 1637
1638 cpus_write_lock(); 1638 cpus_write_lock();
1639 1639
1640 if (!cpu_present(cpu)) { 1640 if (!cpu_present(cpu)) {
1641 ret = -EINVAL; 1641 ret = -EINVAL;
1642 goto out; 1642 goto out;
1643 } 1643 }
1644 1644
1645 /* 1645 /*
1646 * The caller of cpu_up() might have 1646 * The caller of cpu_up() might have raced with another
1647 * caller. Nothing to do. 1647 * caller. Nothing to do.
1648 */ 1648 */
1649 if (st->state >= target) 1649 if (st->state >= target)
1650 goto out; 1650 goto out;
1651 1651
1652 if (st->state == CPUHP_OFFLINE) { 1652 if (st->state == CPUHP_OFFLINE) {
1653 /* Let it fail before we try 1653 /* Let it fail before we try to bring the cpu up */
1654 idle = idle_thread_get(cpu); 1654 idle = idle_thread_get(cpu);
1655 if (IS_ERR(idle)) { 1655 if (IS_ERR(idle)) {
1656 ret = PTR_ERR(idle); 1656 ret = PTR_ERR(idle);
1657 goto out; 1657 goto out;
1658 } 1658 }
1659 1659
1660 /* 1660 /*
1661 * Reset stale stack state fr 1661 * Reset stale stack state from the last time this CPU was online.
1662 */ 1662 */
1663 scs_task_reset(idle); 1663 scs_task_reset(idle);
1664 kasan_unpoison_task_stack(idl 1664 kasan_unpoison_task_stack(idle);
1665 } 1665 }
1666 1666
1667 cpuhp_tasks_frozen = tasks_frozen; 1667 cpuhp_tasks_frozen = tasks_frozen;
1668 1668
1669 cpuhp_set_state(cpu, st, target); 1669 cpuhp_set_state(cpu, st, target);
1670 /* 1670 /*
1671 * If the current CPU state is in the 1671 * If the current CPU state is in the range of the AP hotplug thread,
1672 * then we need to kick the thread on 1672 * then we need to kick the thread once more.
1673 */ 1673 */
1674 if (st->state > CPUHP_BRINGUP_CPU) { 1674 if (st->state > CPUHP_BRINGUP_CPU) {
1675 ret = cpuhp_kick_ap_work(cpu) 1675 ret = cpuhp_kick_ap_work(cpu);
1676 /* 1676 /*
1677 * The AP side has done the e 1677 * The AP side has done the error rollback already. Just
1678 * return the error code.. 1678 * return the error code..
1679 */ 1679 */
1680 if (ret) 1680 if (ret)
1681 goto out; 1681 goto out;
1682 } 1682 }
1683 1683
1684 /* 1684 /*
1685 * Try to reach the target state. We 1685 * Try to reach the target state. We max out on the BP at
1686 * CPUHP_BRINGUP_CPU. After that the 1686 * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is
1687 * responsible for bringing it up to 1687 * responsible for bringing it up to the target state.
1688 */ 1688 */
1689 target = min((int)target, CPUHP_BRING 1689 target = min((int)target, CPUHP_BRINGUP_CPU);
1690 ret = cpuhp_up_callbacks(cpu, st, tar 1690 ret = cpuhp_up_callbacks(cpu, st, target);
1691 out: 1691 out:
1692 cpus_write_unlock(); 1692 cpus_write_unlock();
1693 arch_smt_update(); 1693 arch_smt_update();
1694 return ret; 1694 return ret;
1695 } 1695 }
1696 1696
1697 static int cpu_up(unsigned int cpu, enum cpuh 1697 static int cpu_up(unsigned int cpu, enum cpuhp_state target)
1698 { 1698 {
1699 int err = 0; 1699 int err = 0;
1700 1700
1701 if (!cpu_possible(cpu)) { 1701 if (!cpu_possible(cpu)) {
1702 pr_err("can't online cpu %d b 1702 pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n",
1703 cpu); 1703 cpu);
1704 return -EINVAL; 1704 return -EINVAL;
1705 } 1705 }
1706 1706
1707 err = try_online_node(cpu_to_node(cpu 1707 err = try_online_node(cpu_to_node(cpu));
1708 if (err) 1708 if (err)
1709 return err; 1709 return err;
1710 1710
1711 cpu_maps_update_begin(); 1711 cpu_maps_update_begin();
1712 1712
1713 if (cpu_hotplug_disabled) { 1713 if (cpu_hotplug_disabled) {
1714 err = -EBUSY; 1714 err = -EBUSY;
1715 goto out; 1715 goto out;
1716 } 1716 }
1717 if (!cpu_bootable(cpu)) { 1717 if (!cpu_bootable(cpu)) {
1718 err = -EPERM; 1718 err = -EPERM;
1719 goto out; 1719 goto out;
1720 } 1720 }
1721 1721
1722 err = _cpu_up(cpu, 0, target); 1722 err = _cpu_up(cpu, 0, target);
1723 out: 1723 out:
1724 cpu_maps_update_done(); 1724 cpu_maps_update_done();
1725 return err; 1725 return err;
1726 } 1726 }
1727 1727
1728 /** 1728 /**
1729 * cpu_device_up - Bring up a cpu device 1729 * cpu_device_up - Bring up a cpu device
1730 * @dev: Pointer to the cpu device to online 1730 * @dev: Pointer to the cpu device to online
1731 * 1731 *
1732 * This function is meant to be used by devic 1732 * This function is meant to be used by device core cpu subsystem only.
1733 * 1733 *
1734 * Other subsystems should use add_cpu() inst 1734 * Other subsystems should use add_cpu() instead.
1735 * 1735 *
1736 * Return: %0 on success or a negative errno 1736 * Return: %0 on success or a negative errno code
1737 */ 1737 */
1738 int cpu_device_up(struct device *dev) 1738 int cpu_device_up(struct device *dev)
1739 { 1739 {
1740 return cpu_up(dev->id, CPUHP_ONLINE); 1740 return cpu_up(dev->id, CPUHP_ONLINE);
1741 } 1741 }
1742 1742
1743 int add_cpu(unsigned int cpu) 1743 int add_cpu(unsigned int cpu)
1744 { 1744 {
1745 int ret; 1745 int ret;
1746 1746
1747 lock_device_hotplug(); 1747 lock_device_hotplug();
1748 ret = device_online(get_cpu_device(cp 1748 ret = device_online(get_cpu_device(cpu));
1749 unlock_device_hotplug(); 1749 unlock_device_hotplug();
1750 1750
1751 return ret; 1751 return ret;
1752 } 1752 }
1753 EXPORT_SYMBOL_GPL(add_cpu); 1753 EXPORT_SYMBOL_GPL(add_cpu);
1754 1754
1755 /** 1755 /**
1756 * bringup_hibernate_cpu - Bring up the CPU t 1756 * bringup_hibernate_cpu - Bring up the CPU that we hibernated on
1757 * @sleep_cpu: The cpu we hibernated on and s 1757 * @sleep_cpu: The cpu we hibernated on and should be brought up.
1758 * 1758 *
1759 * On some architectures like arm64, we can h 1759 * On some architectures like arm64, we can hibernate on any CPU, but on
1760 * wake up the CPU we hibernated on might be 1760 * wake up the CPU we hibernated on might be offline as a side effect of
1761 * using maxcpus= for example. 1761 * using maxcpus= for example.
1762 * 1762 *
1763 * Return: %0 on success or a negative errno 1763 * Return: %0 on success or a negative errno code
1764 */ 1764 */
1765 int bringup_hibernate_cpu(unsigned int sleep_ 1765 int bringup_hibernate_cpu(unsigned int sleep_cpu)
1766 { 1766 {
1767 int ret; 1767 int ret;
1768 1768
1769 if (!cpu_online(sleep_cpu)) { 1769 if (!cpu_online(sleep_cpu)) {
1770 pr_info("Hibernated on a CPU 1770 pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
1771 ret = cpu_up(sleep_cpu, CPUHP 1771 ret = cpu_up(sleep_cpu, CPUHP_ONLINE);
1772 if (ret) { 1772 if (ret) {
1773 pr_err("Failed to bri 1773 pr_err("Failed to bring hibernate-CPU up!\n");
1774 return ret; 1774 return ret;
1775 } 1775 }
1776 } 1776 }
1777 return 0; 1777 return 0;
1778 } 1778 }
1779 1779
1780 static void __init cpuhp_bringup_mask(const s 1780 static void __init cpuhp_bringup_mask(const struct cpumask *mask, unsigned int ncpus,
1781 enum cp 1781 enum cpuhp_state target)
1782 { 1782 {
1783 unsigned int cpu; 1783 unsigned int cpu;
1784 1784
1785 for_each_cpu(cpu, mask) { 1785 for_each_cpu(cpu, mask) {
1786 struct cpuhp_cpu_state *st = 1786 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
1787 1787
1788 if (cpu_up(cpu, target) && ca 1788 if (cpu_up(cpu, target) && can_rollback_cpu(st)) {
1789 /* 1789 /*
1790 * If this failed the 1790 * If this failed then cpu_up() might have only
1791 * rolled back to CPU 1791 * rolled back to CPUHP_BP_KICK_AP for the final
1792 * online. Clean it u 1792 * online. Clean it up. NOOP if already rolled back.
1793 */ 1793 */
1794 WARN_ON(cpuhp_invoke_ 1794 WARN_ON(cpuhp_invoke_callback_range(false, cpu, st, CPUHP_OFFLINE));
1795 } 1795 }
1796 1796
1797 if (!--ncpus) 1797 if (!--ncpus)
1798 break; 1798 break;
1799 } 1799 }
1800 } 1800 }
1801 1801
1802 #ifdef CONFIG_HOTPLUG_PARALLEL 1802 #ifdef CONFIG_HOTPLUG_PARALLEL
1803 static bool __cpuhp_parallel_bringup __ro_aft 1803 static bool __cpuhp_parallel_bringup __ro_after_init = true;
1804 1804
1805 static int __init parallel_bringup_parse_para 1805 static int __init parallel_bringup_parse_param(char *arg)
1806 { 1806 {
1807 return kstrtobool(arg, &__cpuhp_paral 1807 return kstrtobool(arg, &__cpuhp_parallel_bringup);
1808 } 1808 }
1809 early_param("cpuhp.parallel", parallel_bringu 1809 early_param("cpuhp.parallel", parallel_bringup_parse_param);
1810 1810
1811 #ifdef CONFIG_HOTPLUG_SMT 1811 #ifdef CONFIG_HOTPLUG_SMT
1812 static inline bool cpuhp_smt_aware(void) 1812 static inline bool cpuhp_smt_aware(void)
1813 { 1813 {
1814 return cpu_smt_max_threads > 1; 1814 return cpu_smt_max_threads > 1;
1815 } 1815 }
1816 1816
1817 static inline const struct cpumask *cpuhp_get 1817 static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)
1818 { 1818 {
1819 return cpu_primary_thread_mask; 1819 return cpu_primary_thread_mask;
1820 } 1820 }
1821 #else 1821 #else
1822 static inline bool cpuhp_smt_aware(void) 1822 static inline bool cpuhp_smt_aware(void)
1823 { 1823 {
1824 return false; 1824 return false;
1825 } 1825 }
1826 static inline const struct cpumask *cpuhp_get 1826 static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)
1827 { 1827 {
1828 return cpu_none_mask; 1828 return cpu_none_mask;
1829 } 1829 }
1830 #endif 1830 #endif
1831 1831
1832 bool __weak arch_cpuhp_init_parallel_bringup( 1832 bool __weak arch_cpuhp_init_parallel_bringup(void)
1833 { 1833 {
1834 return true; 1834 return true;
1835 } 1835 }
1836 1836
1837 /* 1837 /*
1838 * On architectures which have enabled parall 1838 * On architectures which have enabled parallel bringup this invokes all BP
1839 * prepare states for each of the to be onlin 1839 * prepare states for each of the to be onlined APs first. The last state
1840 * sends the startup IPI to the APs. The APs 1840 * sends the startup IPI to the APs. The APs proceed through the low level
1841 * bringup code in parallel and then wait for 1841 * bringup code in parallel and then wait for the control CPU to release
1842 * them one by one for the final onlining pro 1842 * them one by one for the final onlining procedure.
1843 * 1843 *
1844 * This avoids waiting for each AP to respond 1844 * This avoids waiting for each AP to respond to the startup IPI in
1845 * CPUHP_BRINGUP_CPU. 1845 * CPUHP_BRINGUP_CPU.
1846 */ 1846 */
1847 static bool __init cpuhp_bringup_cpus_paralle 1847 static bool __init cpuhp_bringup_cpus_parallel(unsigned int ncpus)
1848 { 1848 {
1849 const struct cpumask *mask = cpu_pres 1849 const struct cpumask *mask = cpu_present_mask;
1850 1850
1851 if (__cpuhp_parallel_bringup) 1851 if (__cpuhp_parallel_bringup)
1852 __cpuhp_parallel_bringup = ar 1852 __cpuhp_parallel_bringup = arch_cpuhp_init_parallel_bringup();
1853 if (!__cpuhp_parallel_bringup) 1853 if (!__cpuhp_parallel_bringup)
1854 return false; 1854 return false;
1855 1855
1856 if (cpuhp_smt_aware()) { 1856 if (cpuhp_smt_aware()) {
1857 const struct cpumask *pmask = 1857 const struct cpumask *pmask = cpuhp_get_primary_thread_mask();
1858 static struct cpumask tmp_mas 1858 static struct cpumask tmp_mask __initdata;
1859 1859
1860 /* 1860 /*
1861 * X86 requires to prevent th 1861 * X86 requires to prevent that SMT siblings stopped while
1862 * the primary thread does a 1862 * the primary thread does a microcode update for various
1863 * reasons. Bring the primary 1863 * reasons. Bring the primary threads up first.
1864 */ 1864 */
1865 cpumask_and(&tmp_mask, mask, 1865 cpumask_and(&tmp_mask, mask, pmask);
1866 cpuhp_bringup_mask(&tmp_mask, 1866 cpuhp_bringup_mask(&tmp_mask, ncpus, CPUHP_BP_KICK_AP);
1867 cpuhp_bringup_mask(&tmp_mask, 1867 cpuhp_bringup_mask(&tmp_mask, ncpus, CPUHP_ONLINE);
1868 /* Account for the online CPU 1868 /* Account for the online CPUs */
1869 ncpus -= num_online_cpus(); 1869 ncpus -= num_online_cpus();
1870 if (!ncpus) 1870 if (!ncpus)
1871 return true; 1871 return true;
1872 /* Create the mask for second 1872 /* Create the mask for secondary CPUs */
1873 cpumask_andnot(&tmp_mask, mas 1873 cpumask_andnot(&tmp_mask, mask, pmask);
1874 mask = &tmp_mask; 1874 mask = &tmp_mask;
1875 } 1875 }
1876 1876
1877 /* Bring the not-yet started CPUs up 1877 /* Bring the not-yet started CPUs up */
1878 cpuhp_bringup_mask(mask, ncpus, CPUHP 1878 cpuhp_bringup_mask(mask, ncpus, CPUHP_BP_KICK_AP);
1879 cpuhp_bringup_mask(mask, ncpus, CPUHP 1879 cpuhp_bringup_mask(mask, ncpus, CPUHP_ONLINE);
1880 return true; 1880 return true;
1881 } 1881 }
1882 #else 1882 #else
1883 static inline bool cpuhp_bringup_cpus_paralle 1883 static inline bool cpuhp_bringup_cpus_parallel(unsigned int ncpus) { return false; }
1884 #endif /* CONFIG_HOTPLUG_PARALLEL */ 1884 #endif /* CONFIG_HOTPLUG_PARALLEL */
1885 1885
1886 void __init bringup_nonboot_cpus(unsigned int 1886 void __init bringup_nonboot_cpus(unsigned int max_cpus)
1887 { 1887 {
1888 if (!max_cpus) 1888 if (!max_cpus)
1889 return; 1889 return;
1890 1890
1891 /* Try parallel bringup optimization 1891 /* Try parallel bringup optimization if enabled */
1892 if (cpuhp_bringup_cpus_parallel(max_c 1892 if (cpuhp_bringup_cpus_parallel(max_cpus))
1893 return; 1893 return;
1894 1894
1895 /* Full per CPU serialized bringup */ 1895 /* Full per CPU serialized bringup */
1896 cpuhp_bringup_mask(cpu_present_mask, 1896 cpuhp_bringup_mask(cpu_present_mask, max_cpus, CPUHP_ONLINE);
1897 } 1897 }
1898 1898
1899 #ifdef CONFIG_PM_SLEEP_SMP 1899 #ifdef CONFIG_PM_SLEEP_SMP
1900 static cpumask_var_t frozen_cpus; 1900 static cpumask_var_t frozen_cpus;
1901 1901
1902 int freeze_secondary_cpus(int primary) 1902 int freeze_secondary_cpus(int primary)
1903 { 1903 {
1904 int cpu, error = 0; 1904 int cpu, error = 0;
1905 1905
1906 cpu_maps_update_begin(); 1906 cpu_maps_update_begin();
1907 if (primary == -1) { 1907 if (primary == -1) {
1908 primary = cpumask_first(cpu_o 1908 primary = cpumask_first(cpu_online_mask);
1909 if (!housekeeping_cpu(primary 1909 if (!housekeeping_cpu(primary, HK_TYPE_TIMER))
1910 primary = housekeepin 1910 primary = housekeeping_any_cpu(HK_TYPE_TIMER);
1911 } else { 1911 } else {
1912 if (!cpu_online(primary)) 1912 if (!cpu_online(primary))
1913 primary = cpumask_fir 1913 primary = cpumask_first(cpu_online_mask);
1914 } 1914 }
1915 1915
1916 /* 1916 /*
1917 * We take down all of the non-boot C 1917 * We take down all of the non-boot CPUs in one shot to avoid races
1918 * with the userspace trying to use t 1918 * with the userspace trying to use the CPU hotplug at the same time
1919 */ 1919 */
1920 cpumask_clear(frozen_cpus); 1920 cpumask_clear(frozen_cpus);
1921 1921
1922 pr_info("Disabling non-boot CPUs ...\ 1922 pr_info("Disabling non-boot CPUs ...\n");
1923 for (cpu = nr_cpu_ids - 1; cpu >= 0; 1923 for (cpu = nr_cpu_ids - 1; cpu >= 0; cpu--) {
1924 if (!cpu_online(cpu) || cpu = 1924 if (!cpu_online(cpu) || cpu == primary)
1925 continue; 1925 continue;
1926 1926
1927 if (pm_wakeup_pending()) { 1927 if (pm_wakeup_pending()) {
1928 pr_info("Wakeup pendi 1928 pr_info("Wakeup pending. Abort CPU freeze\n");
1929 error = -EBUSY; 1929 error = -EBUSY;
1930 break; 1930 break;
1931 } 1931 }
1932 1932
1933 trace_suspend_resume(TPS("CPU 1933 trace_suspend_resume(TPS("CPU_OFF"), cpu, true);
1934 error = _cpu_down(cpu, 1, CPU 1934 error = _cpu_down(cpu, 1, CPUHP_OFFLINE);
1935 trace_suspend_resume(TPS("CPU 1935 trace_suspend_resume(TPS("CPU_OFF"), cpu, false);
1936 if (!error) 1936 if (!error)
1937 cpumask_set_cpu(cpu, 1937 cpumask_set_cpu(cpu, frozen_cpus);
1938 else { 1938 else {
1939 pr_err("Error taking 1939 pr_err("Error taking CPU%d down: %d\n", cpu, error);
1940 break; 1940 break;
1941 } 1941 }
1942 } 1942 }
1943 1943
1944 if (!error) 1944 if (!error)
1945 BUG_ON(num_online_cpus() > 1) 1945 BUG_ON(num_online_cpus() > 1);
1946 else 1946 else
1947 pr_err("Non-boot CPUs are not 1947 pr_err("Non-boot CPUs are not disabled\n");
1948 1948
1949 /* 1949 /*
1950 * Make sure the CPUs won't be enable 1950 * Make sure the CPUs won't be enabled by someone else. We need to do
1951 * this even in case of failure as al 1951 * this even in case of failure as all freeze_secondary_cpus() users are
1952 * supposed to do thaw_secondary_cpus 1952 * supposed to do thaw_secondary_cpus() on the failure path.
1953 */ 1953 */
1954 cpu_hotplug_disabled++; 1954 cpu_hotplug_disabled++;
1955 1955
1956 cpu_maps_update_done(); 1956 cpu_maps_update_done();
1957 return error; 1957 return error;
1958 } 1958 }
1959 1959
1960 void __weak arch_thaw_secondary_cpus_begin(vo 1960 void __weak arch_thaw_secondary_cpus_begin(void)
1961 { 1961 {
1962 } 1962 }
1963 1963
1964 void __weak arch_thaw_secondary_cpus_end(void 1964 void __weak arch_thaw_secondary_cpus_end(void)
1965 { 1965 {
1966 } 1966 }
1967 1967
1968 void thaw_secondary_cpus(void) 1968 void thaw_secondary_cpus(void)
1969 { 1969 {
1970 int cpu, error; 1970 int cpu, error;
1971 1971
1972 /* Allow everyone to use the CPU hotp 1972 /* Allow everyone to use the CPU hotplug again */
1973 cpu_maps_update_begin(); 1973 cpu_maps_update_begin();
1974 __cpu_hotplug_enable(); 1974 __cpu_hotplug_enable();
1975 if (cpumask_empty(frozen_cpus)) 1975 if (cpumask_empty(frozen_cpus))
1976 goto out; 1976 goto out;
1977 1977
1978 pr_info("Enabling non-boot CPUs ...\n 1978 pr_info("Enabling non-boot CPUs ...\n");
1979 1979
1980 arch_thaw_secondary_cpus_begin(); 1980 arch_thaw_secondary_cpus_begin();
1981 1981
1982 for_each_cpu(cpu, frozen_cpus) { 1982 for_each_cpu(cpu, frozen_cpus) {
1983 trace_suspend_resume(TPS("CPU 1983 trace_suspend_resume(TPS("CPU_ON"), cpu, true);
1984 error = _cpu_up(cpu, 1, CPUHP 1984 error = _cpu_up(cpu, 1, CPUHP_ONLINE);
1985 trace_suspend_resume(TPS("CPU 1985 trace_suspend_resume(TPS("CPU_ON"), cpu, false);
1986 if (!error) { 1986 if (!error) {
1987 pr_info("CPU%d is up\ 1987 pr_info("CPU%d is up\n", cpu);
1988 continue; 1988 continue;
1989 } 1989 }
1990 pr_warn("Error taking CPU%d u 1990 pr_warn("Error taking CPU%d up: %d\n", cpu, error);
1991 } 1991 }
1992 1992
1993 arch_thaw_secondary_cpus_end(); 1993 arch_thaw_secondary_cpus_end();
1994 1994
1995 cpumask_clear(frozen_cpus); 1995 cpumask_clear(frozen_cpus);
1996 out: 1996 out:
1997 cpu_maps_update_done(); 1997 cpu_maps_update_done();
1998 } 1998 }
1999 1999
2000 static int __init alloc_frozen_cpus(void) 2000 static int __init alloc_frozen_cpus(void)
2001 { 2001 {
2002 if (!alloc_cpumask_var(&frozen_cpus, 2002 if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO))
2003 return -ENOMEM; 2003 return -ENOMEM;
2004 return 0; 2004 return 0;
2005 } 2005 }
2006 core_initcall(alloc_frozen_cpus); 2006 core_initcall(alloc_frozen_cpus);
2007 2007
2008 /* 2008 /*
2009 * When callbacks for CPU hotplug notificatio 2009 * When callbacks for CPU hotplug notifications are being executed, we must
2010 * ensure that the state of the system with r 2010 * ensure that the state of the system with respect to the tasks being frozen
2011 * or not, as reported by the notification, r 2011 * or not, as reported by the notification, remains unchanged *throughout the
2012 * duration* of the execution of the callback 2012 * duration* of the execution of the callbacks.
2013 * Hence we need to prevent the freezer from 2013 * Hence we need to prevent the freezer from racing with regular CPU hotplug.
2014 * 2014 *
2015 * This synchronization is implemented by mut 2015 * This synchronization is implemented by mutually excluding regular CPU
2016 * hotplug and Suspend/Hibernate call paths b 2016 * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/
2017 * Hibernate notifications. 2017 * Hibernate notifications.
2018 */ 2018 */
2019 static int 2019 static int
2020 cpu_hotplug_pm_callback(struct notifier_block 2020 cpu_hotplug_pm_callback(struct notifier_block *nb,
2021 unsigned long action, 2021 unsigned long action, void *ptr)
2022 { 2022 {
2023 switch (action) { 2023 switch (action) {
2024 2024
2025 case PM_SUSPEND_PREPARE: 2025 case PM_SUSPEND_PREPARE:
2026 case PM_HIBERNATION_PREPARE: 2026 case PM_HIBERNATION_PREPARE:
2027 cpu_hotplug_disable(); 2027 cpu_hotplug_disable();
2028 break; 2028 break;
2029 2029
2030 case PM_POST_SUSPEND: 2030 case PM_POST_SUSPEND:
2031 case PM_POST_HIBERNATION: 2031 case PM_POST_HIBERNATION:
2032 cpu_hotplug_enable(); 2032 cpu_hotplug_enable();
2033 break; 2033 break;
2034 2034
2035 default: 2035 default:
2036 return NOTIFY_DONE; 2036 return NOTIFY_DONE;
2037 } 2037 }
2038 2038
2039 return NOTIFY_OK; 2039 return NOTIFY_OK;
2040 } 2040 }
2041 2041
2042 2042
2043 static int __init cpu_hotplug_pm_sync_init(vo 2043 static int __init cpu_hotplug_pm_sync_init(void)
2044 { 2044 {
2045 /* 2045 /*
2046 * cpu_hotplug_pm_callback has higher 2046 * cpu_hotplug_pm_callback has higher priority than x86
2047 * bsp_pm_callback which depends on c 2047 * bsp_pm_callback which depends on cpu_hotplug_pm_callback
2048 * to disable cpu hotplug to avoid cp 2048 * to disable cpu hotplug to avoid cpu hotplug race.
2049 */ 2049 */
2050 pm_notifier(cpu_hotplug_pm_callback, 2050 pm_notifier(cpu_hotplug_pm_callback, 0);
2051 return 0; 2051 return 0;
2052 } 2052 }
2053 core_initcall(cpu_hotplug_pm_sync_init); 2053 core_initcall(cpu_hotplug_pm_sync_init);
2054 2054
2055 #endif /* CONFIG_PM_SLEEP_SMP */ 2055 #endif /* CONFIG_PM_SLEEP_SMP */
2056 2056
2057 int __boot_cpu_id; 2057 int __boot_cpu_id;
2058 2058
2059 #endif /* CONFIG_SMP */ 2059 #endif /* CONFIG_SMP */
2060 2060
2061 /* Boot processor state steps */ 2061 /* Boot processor state steps */
2062 static struct cpuhp_step cpuhp_hp_states[] = 2062 static struct cpuhp_step cpuhp_hp_states[] = {
2063 [CPUHP_OFFLINE] = { 2063 [CPUHP_OFFLINE] = {
2064 .name = "of 2064 .name = "offline",
2065 .startup.single = NUL 2065 .startup.single = NULL,
2066 .teardown.single = NUL 2066 .teardown.single = NULL,
2067 }, 2067 },
2068 #ifdef CONFIG_SMP 2068 #ifdef CONFIG_SMP
2069 [CPUHP_CREATE_THREADS]= { 2069 [CPUHP_CREATE_THREADS]= {
2070 .name = "th 2070 .name = "threads:prepare",
2071 .startup.single = smp 2071 .startup.single = smpboot_create_threads,
2072 .teardown.single = NUL 2072 .teardown.single = NULL,
2073 .cant_stop = tru 2073 .cant_stop = true,
2074 }, 2074 },
2075 [CPUHP_PERF_PREPARE] = { 2075 [CPUHP_PERF_PREPARE] = {
2076 .name = "pe 2076 .name = "perf:prepare",
2077 .startup.single = per 2077 .startup.single = perf_event_init_cpu,
2078 .teardown.single = per 2078 .teardown.single = perf_event_exit_cpu,
2079 }, 2079 },
2080 [CPUHP_RANDOM_PREPARE] = { 2080 [CPUHP_RANDOM_PREPARE] = {
2081 .name = "ra 2081 .name = "random:prepare",
2082 .startup.single = ran 2082 .startup.single = random_prepare_cpu,
2083 .teardown.single = NUL 2083 .teardown.single = NULL,
2084 }, 2084 },
2085 [CPUHP_WORKQUEUE_PREP] = { 2085 [CPUHP_WORKQUEUE_PREP] = {
2086 .name = "wo 2086 .name = "workqueue:prepare",
2087 .startup.single = wor 2087 .startup.single = workqueue_prepare_cpu,
2088 .teardown.single = NUL 2088 .teardown.single = NULL,
2089 }, 2089 },
2090 [CPUHP_HRTIMERS_PREPARE] = { 2090 [CPUHP_HRTIMERS_PREPARE] = {
2091 .name = "hr 2091 .name = "hrtimers:prepare",
2092 .startup.single = hrt 2092 .startup.single = hrtimers_prepare_cpu,
2093 .teardown.single = NUL 2093 .teardown.single = NULL,
2094 }, 2094 },
2095 [CPUHP_SMPCFD_PREPARE] = { 2095 [CPUHP_SMPCFD_PREPARE] = {
2096 .name = "sm 2096 .name = "smpcfd:prepare",
2097 .startup.single = smp 2097 .startup.single = smpcfd_prepare_cpu,
2098 .teardown.single = smp 2098 .teardown.single = smpcfd_dead_cpu,
2099 }, 2099 },
2100 [CPUHP_RELAY_PREPARE] = { 2100 [CPUHP_RELAY_PREPARE] = {
2101 .name = "re 2101 .name = "relay:prepare",
2102 .startup.single = rel 2102 .startup.single = relay_prepare_cpu,
2103 .teardown.single = NUL 2103 .teardown.single = NULL,
2104 }, 2104 },
2105 [CPUHP_RCUTREE_PREP] = { 2105 [CPUHP_RCUTREE_PREP] = {
2106 .name = "RC 2106 .name = "RCU/tree:prepare",
2107 .startup.single = rcu 2107 .startup.single = rcutree_prepare_cpu,
2108 .teardown.single = rcu 2108 .teardown.single = rcutree_dead_cpu,
2109 }, 2109 },
2110 /* 2110 /*
2111 * On the tear-down path, timers_dead 2111 * On the tear-down path, timers_dead_cpu() must be invoked
2112 * before blk_mq_queue_reinit_notify( 2112 * before blk_mq_queue_reinit_notify() from notify_dead(),
2113 * otherwise a RCU stall occurs. 2113 * otherwise a RCU stall occurs.
2114 */ 2114 */
2115 [CPUHP_TIMERS_PREPARE] = { 2115 [CPUHP_TIMERS_PREPARE] = {
2116 .name = "ti 2116 .name = "timers:prepare",
2117 .startup.single = tim 2117 .startup.single = timers_prepare_cpu,
2118 .teardown.single = tim 2118 .teardown.single = timers_dead_cpu,
2119 }, 2119 },
2120 2120
2121 #ifdef CONFIG_HOTPLUG_SPLIT_STARTUP 2121 #ifdef CONFIG_HOTPLUG_SPLIT_STARTUP
2122 /* 2122 /*
2123 * Kicks the AP alive. AP will wait i 2123 * Kicks the AP alive. AP will wait in cpuhp_ap_sync_alive() until
2124 * the next step will release it. 2124 * the next step will release it.
2125 */ 2125 */
2126 [CPUHP_BP_KICK_AP] = { 2126 [CPUHP_BP_KICK_AP] = {
2127 .name = "cp 2127 .name = "cpu:kick_ap",
2128 .startup.single = cpu 2128 .startup.single = cpuhp_kick_ap_alive,
2129 }, 2129 },
2130 2130
2131 /* 2131 /*
2132 * Waits for the AP to reach cpuhp_ap 2132 * Waits for the AP to reach cpuhp_ap_sync_alive() and then
2133 * releases it for the complete bring 2133 * releases it for the complete bringup.
2134 */ 2134 */
2135 [CPUHP_BRINGUP_CPU] = { 2135 [CPUHP_BRINGUP_CPU] = {
2136 .name = "cp 2136 .name = "cpu:bringup",
2137 .startup.single = cpu 2137 .startup.single = cpuhp_bringup_ap,
2138 .teardown.single = fin 2138 .teardown.single = finish_cpu,
2139 .cant_stop = tru 2139 .cant_stop = true,
2140 }, 2140 },
2141 #else 2141 #else
2142 /* 2142 /*
2143 * All-in-one CPU bringup state which 2143 * All-in-one CPU bringup state which includes the kick alive.
2144 */ 2144 */
2145 [CPUHP_BRINGUP_CPU] = { 2145 [CPUHP_BRINGUP_CPU] = {
2146 .name = "cp 2146 .name = "cpu:bringup",
2147 .startup.single = bri 2147 .startup.single = bringup_cpu,
2148 .teardown.single = fin 2148 .teardown.single = finish_cpu,
2149 .cant_stop = tru 2149 .cant_stop = true,
2150 }, 2150 },
2151 #endif 2151 #endif
2152 /* Final state before CPU kills itsel 2152 /* Final state before CPU kills itself */
2153 [CPUHP_AP_IDLE_DEAD] = { 2153 [CPUHP_AP_IDLE_DEAD] = {
2154 .name = "id 2154 .name = "idle:dead",
2155 }, 2155 },
2156 /* 2156 /*
2157 * Last state before CPU enters the i 2157 * Last state before CPU enters the idle loop to die. Transient state
2158 * for synchronization. 2158 * for synchronization.
2159 */ 2159 */
2160 [CPUHP_AP_OFFLINE] = { 2160 [CPUHP_AP_OFFLINE] = {
2161 .name = "ap 2161 .name = "ap:offline",
2162 .cant_stop = tru 2162 .cant_stop = true,
2163 }, 2163 },
2164 /* First state is scheduler control. 2164 /* First state is scheduler control. Interrupts are disabled */
2165 [CPUHP_AP_SCHED_STARTING] = { 2165 [CPUHP_AP_SCHED_STARTING] = {
2166 .name = "sc 2166 .name = "sched:starting",
2167 .startup.single = sch 2167 .startup.single = sched_cpu_starting,
2168 .teardown.single = sch 2168 .teardown.single = sched_cpu_dying,
2169 }, 2169 },
2170 [CPUHP_AP_RCUTREE_DYING] = { 2170 [CPUHP_AP_RCUTREE_DYING] = {
2171 .name = "RC 2171 .name = "RCU/tree:dying",
2172 .startup.single = NUL 2172 .startup.single = NULL,
2173 .teardown.single = rcu 2173 .teardown.single = rcutree_dying_cpu,
2174 }, 2174 },
2175 [CPUHP_AP_SMPCFD_DYING] = { 2175 [CPUHP_AP_SMPCFD_DYING] = {
2176 .name = "sm 2176 .name = "smpcfd:dying",
2177 .startup.single = NUL 2177 .startup.single = NULL,
2178 .teardown.single = smp 2178 .teardown.single = smpcfd_dying_cpu,
2179 }, 2179 },
2180 [CPUHP_AP_HRTIMERS_DYING] = { 2180 [CPUHP_AP_HRTIMERS_DYING] = {
2181 .name = "hr 2181 .name = "hrtimers:dying",
2182 .startup.single = NUL 2182 .startup.single = NULL,
2183 .teardown.single = hrt 2183 .teardown.single = hrtimers_cpu_dying,
2184 }, 2184 },
2185 [CPUHP_AP_TICK_DYING] = { 2185 [CPUHP_AP_TICK_DYING] = {
2186 .name = "ti 2186 .name = "tick:dying",
2187 .startup.single = NUL 2187 .startup.single = NULL,
2188 .teardown.single = tic 2188 .teardown.single = tick_cpu_dying,
2189 }, 2189 },
2190 /* Entry state on starting. Interrupt 2190 /* Entry state on starting. Interrupts enabled from here on. Transient
2191 * state for synchronsization */ 2191 * state for synchronsization */
2192 [CPUHP_AP_ONLINE] = { 2192 [CPUHP_AP_ONLINE] = {
2193 .name = "ap 2193 .name = "ap:online",
2194 }, 2194 },
2195 /* 2195 /*
2196 * Handled on control processor until 2196 * Handled on control processor until the plugged processor manages
2197 * this itself. 2197 * this itself.
2198 */ 2198 */
2199 [CPUHP_TEARDOWN_CPU] = { 2199 [CPUHP_TEARDOWN_CPU] = {
2200 .name = "cp 2200 .name = "cpu:teardown",
2201 .startup.single = NUL 2201 .startup.single = NULL,
2202 .teardown.single = tak 2202 .teardown.single = takedown_cpu,
2203 .cant_stop = tru 2203 .cant_stop = true,
2204 }, 2204 },
2205 2205
2206 [CPUHP_AP_SCHED_WAIT_EMPTY] = { 2206 [CPUHP_AP_SCHED_WAIT_EMPTY] = {
2207 .name = "sc 2207 .name = "sched:waitempty",
2208 .startup.single = NUL 2208 .startup.single = NULL,
2209 .teardown.single = sch 2209 .teardown.single = sched_cpu_wait_empty,
2210 }, 2210 },
2211 2211
2212 /* Handle smpboot threads park/unpark 2212 /* Handle smpboot threads park/unpark */
2213 [CPUHP_AP_SMPBOOT_THREADS] = { 2213 [CPUHP_AP_SMPBOOT_THREADS] = {
2214 .name = "sm 2214 .name = "smpboot/threads:online",
2215 .startup.single = smp 2215 .startup.single = smpboot_unpark_threads,
2216 .teardown.single = smp 2216 .teardown.single = smpboot_park_threads,
2217 }, 2217 },
2218 [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { 2218 [CPUHP_AP_IRQ_AFFINITY_ONLINE] = {
2219 .name = "ir 2219 .name = "irq/affinity:online",
2220 .startup.single = irq 2220 .startup.single = irq_affinity_online_cpu,
2221 .teardown.single = NUL 2221 .teardown.single = NULL,
2222 }, 2222 },
2223 [CPUHP_AP_PERF_ONLINE] = { 2223 [CPUHP_AP_PERF_ONLINE] = {
2224 .name = "pe 2224 .name = "perf:online",
2225 .startup.single = per 2225 .startup.single = perf_event_init_cpu,
2226 .teardown.single = per 2226 .teardown.single = perf_event_exit_cpu,
2227 }, 2227 },
2228 [CPUHP_AP_WATCHDOG_ONLINE] = { 2228 [CPUHP_AP_WATCHDOG_ONLINE] = {
2229 .name = "lo 2229 .name = "lockup_detector:online",
2230 .startup.single = loc 2230 .startup.single = lockup_detector_online_cpu,
2231 .teardown.single = loc 2231 .teardown.single = lockup_detector_offline_cpu,
2232 }, 2232 },
2233 [CPUHP_AP_WORKQUEUE_ONLINE] = { 2233 [CPUHP_AP_WORKQUEUE_ONLINE] = {
2234 .name = "wo 2234 .name = "workqueue:online",
2235 .startup.single = wor 2235 .startup.single = workqueue_online_cpu,
2236 .teardown.single = wor 2236 .teardown.single = workqueue_offline_cpu,
2237 }, 2237 },
2238 [CPUHP_AP_RANDOM_ONLINE] = { 2238 [CPUHP_AP_RANDOM_ONLINE] = {
2239 .name = "ra 2239 .name = "random:online",
2240 .startup.single = ran 2240 .startup.single = random_online_cpu,
2241 .teardown.single = NUL 2241 .teardown.single = NULL,
2242 }, 2242 },
2243 [CPUHP_AP_RCUTREE_ONLINE] = { 2243 [CPUHP_AP_RCUTREE_ONLINE] = {
2244 .name = "RC 2244 .name = "RCU/tree:online",
2245 .startup.single = rcu 2245 .startup.single = rcutree_online_cpu,
2246 .teardown.single = rcu 2246 .teardown.single = rcutree_offline_cpu,
2247 }, 2247 },
2248 #endif 2248 #endif
2249 /* 2249 /*
2250 * The dynamically registered state s 2250 * The dynamically registered state space is here
2251 */ 2251 */
2252 2252
2253 #ifdef CONFIG_SMP 2253 #ifdef CONFIG_SMP
2254 /* Last state is scheduler control se 2254 /* Last state is scheduler control setting the cpu active */
2255 [CPUHP_AP_ACTIVE] = { 2255 [CPUHP_AP_ACTIVE] = {
2256 .name = "sc 2256 .name = "sched:active",
2257 .startup.single = sch 2257 .startup.single = sched_cpu_activate,
2258 .teardown.single = sch 2258 .teardown.single = sched_cpu_deactivate,
2259 }, 2259 },
2260 #endif 2260 #endif
2261 2261
2262 /* CPU is fully up and running. */ 2262 /* CPU is fully up and running. */
2263 [CPUHP_ONLINE] = { 2263 [CPUHP_ONLINE] = {
2264 .name = "on 2264 .name = "online",
2265 .startup.single = NUL 2265 .startup.single = NULL,
2266 .teardown.single = NUL 2266 .teardown.single = NULL,
2267 }, 2267 },
2268 }; 2268 };
2269 2269
2270 /* Sanity check for callbacks */ 2270 /* Sanity check for callbacks */
2271 static int cpuhp_cb_check(enum cpuhp_state st 2271 static int cpuhp_cb_check(enum cpuhp_state state)
2272 { 2272 {
2273 if (state <= CPUHP_OFFLINE || state > 2273 if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE)
2274 return -EINVAL; 2274 return -EINVAL;
2275 return 0; 2275 return 0;
2276 } 2276 }
2277 2277
2278 /* 2278 /*
2279 * Returns a free for dynamic slot assignment 2279 * Returns a free for dynamic slot assignment of the Online state. The states
2280 * are protected by the cpuhp_slot_states mut 2280 * are protected by the cpuhp_slot_states mutex and an empty slot is identified
2281 * by having no name assigned. 2281 * by having no name assigned.
2282 */ 2282 */
2283 static int cpuhp_reserve_state(enum cpuhp_sta 2283 static int cpuhp_reserve_state(enum cpuhp_state state)
2284 { 2284 {
2285 enum cpuhp_state i, end; 2285 enum cpuhp_state i, end;
2286 struct cpuhp_step *step; 2286 struct cpuhp_step *step;
2287 2287
2288 switch (state) { 2288 switch (state) {
2289 case CPUHP_AP_ONLINE_DYN: 2289 case CPUHP_AP_ONLINE_DYN:
2290 step = cpuhp_hp_states + CPUH 2290 step = cpuhp_hp_states + CPUHP_AP_ONLINE_DYN;
2291 end = CPUHP_AP_ONLINE_DYN_END 2291 end = CPUHP_AP_ONLINE_DYN_END;
2292 break; 2292 break;
2293 case CPUHP_BP_PREPARE_DYN: 2293 case CPUHP_BP_PREPARE_DYN:
2294 step = cpuhp_hp_states + CPUH 2294 step = cpuhp_hp_states + CPUHP_BP_PREPARE_DYN;
2295 end = CPUHP_BP_PREPARE_DYN_EN 2295 end = CPUHP_BP_PREPARE_DYN_END;
2296 break; 2296 break;
2297 default: 2297 default:
2298 return -EINVAL; 2298 return -EINVAL;
2299 } 2299 }
2300 2300
2301 for (i = state; i <= end; i++, step++ 2301 for (i = state; i <= end; i++, step++) {
2302 if (!step->name) 2302 if (!step->name)
2303 return i; 2303 return i;
2304 } 2304 }
2305 WARN(1, "No more dynamic states avail 2305 WARN(1, "No more dynamic states available for CPU hotplug\n");
2306 return -ENOSPC; 2306 return -ENOSPC;
2307 } 2307 }
2308 2308
2309 static int cpuhp_store_callbacks(enum cpuhp_s 2309 static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name,
2310 int (*startu 2310 int (*startup)(unsigned int cpu),
2311 int (*teardo 2311 int (*teardown)(unsigned int cpu),
2312 bool multi_i 2312 bool multi_instance)
2313 { 2313 {
2314 /* (Un)Install the callbacks for furt 2314 /* (Un)Install the callbacks for further cpu hotplug operations */
2315 struct cpuhp_step *sp; 2315 struct cpuhp_step *sp;
2316 int ret = 0; 2316 int ret = 0;
2317 2317
2318 /* 2318 /*
2319 * If name is NULL, then the state ge 2319 * If name is NULL, then the state gets removed.
2320 * 2320 *
2321 * CPUHP_AP_ONLINE_DYN and CPUHP_BP_P 2321 * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on
2322 * the first allocation from these dy 2322 * the first allocation from these dynamic ranges, so the removal
2323 * would trigger a new allocation and 2323 * would trigger a new allocation and clear the wrong (already
2324 * empty) state, leaving the callback 2324 * empty) state, leaving the callbacks of the to be cleared state
2325 * dangling, which causes wreckage on 2325 * dangling, which causes wreckage on the next hotplug operation.
2326 */ 2326 */
2327 if (name && (state == CPUHP_AP_ONLINE 2327 if (name && (state == CPUHP_AP_ONLINE_DYN ||
2328 state == CPUHP_BP_PREPAR 2328 state == CPUHP_BP_PREPARE_DYN)) {
2329 ret = cpuhp_reserve_state(sta 2329 ret = cpuhp_reserve_state(state);
2330 if (ret < 0) 2330 if (ret < 0)
2331 return ret; 2331 return ret;
2332 state = ret; 2332 state = ret;
2333 } 2333 }
2334 sp = cpuhp_get_step(state); 2334 sp = cpuhp_get_step(state);
2335 if (name && sp->name) 2335 if (name && sp->name)
2336 return -EBUSY; 2336 return -EBUSY;
2337 2337
2338 sp->startup.single = startup; 2338 sp->startup.single = startup;
2339 sp->teardown.single = teardown; 2339 sp->teardown.single = teardown;
2340 sp->name = name; 2340 sp->name = name;
2341 sp->multi_instance = multi_instance; 2341 sp->multi_instance = multi_instance;
2342 INIT_HLIST_HEAD(&sp->list); 2342 INIT_HLIST_HEAD(&sp->list);
2343 return ret; 2343 return ret;
2344 } 2344 }
2345 2345
2346 static void *cpuhp_get_teardown_cb(enum cpuhp 2346 static void *cpuhp_get_teardown_cb(enum cpuhp_state state)
2347 { 2347 {
2348 return cpuhp_get_step(state)->teardow 2348 return cpuhp_get_step(state)->teardown.single;
2349 } 2349 }
2350 2350
2351 /* 2351 /*
2352 * Call the startup/teardown function for a s 2352 * Call the startup/teardown function for a step either on the AP or
2353 * on the current CPU. 2353 * on the current CPU.
2354 */ 2354 */
2355 static int cpuhp_issue_call(int cpu, enum cpu 2355 static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup,
2356 struct hlist_node 2356 struct hlist_node *node)
2357 { 2357 {
2358 struct cpuhp_step *sp = cpuhp_get_ste 2358 struct cpuhp_step *sp = cpuhp_get_step(state);
2359 int ret; 2359 int ret;
2360 2360
2361 /* 2361 /*
2362 * If there's nothing to do, we done. 2362 * If there's nothing to do, we done.
2363 * Relies on the union for multi_inst 2363 * Relies on the union for multi_instance.
2364 */ 2364 */
2365 if (cpuhp_step_empty(bringup, sp)) 2365 if (cpuhp_step_empty(bringup, sp))
2366 return 0; 2366 return 0;
2367 /* 2367 /*
2368 * The non AP bound callbacks can fai 2368 * The non AP bound callbacks can fail on bringup. On teardown
2369 * e.g. module removal we crash for n 2369 * e.g. module removal we crash for now.
2370 */ 2370 */
2371 #ifdef CONFIG_SMP 2371 #ifdef CONFIG_SMP
2372 if (cpuhp_is_ap_state(state)) 2372 if (cpuhp_is_ap_state(state))
2373 ret = cpuhp_invoke_ap_callbac 2373 ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node);
2374 else 2374 else
2375 ret = cpuhp_invoke_callback(c 2375 ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
2376 #else 2376 #else
2377 ret = cpuhp_invoke_callback(cpu, stat 2377 ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL);
2378 #endif 2378 #endif
2379 BUG_ON(ret && !bringup); 2379 BUG_ON(ret && !bringup);
2380 return ret; 2380 return ret;
2381 } 2381 }
2382 2382
2383 /* 2383 /*
2384 * Called from __cpuhp_setup_state on a recov 2384 * Called from __cpuhp_setup_state on a recoverable failure.
2385 * 2385 *
2386 * Note: The teardown callbacks for rollback 2386 * Note: The teardown callbacks for rollback are not allowed to fail!
2387 */ 2387 */
2388 static void cpuhp_rollback_install(int failed 2388 static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state,
2389 struct hli 2389 struct hlist_node *node)
2390 { 2390 {
2391 int cpu; 2391 int cpu;
2392 2392
2393 /* Roll back the already executed ste 2393 /* Roll back the already executed steps on the other cpus */
2394 for_each_present_cpu(cpu) { 2394 for_each_present_cpu(cpu) {
2395 struct cpuhp_cpu_state *st = 2395 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2396 int cpustate = st->state; 2396 int cpustate = st->state;
2397 2397
2398 if (cpu >= failedcpu) 2398 if (cpu >= failedcpu)
2399 break; 2399 break;
2400 2400
2401 /* Did we invoke the startup 2401 /* Did we invoke the startup call on that cpu ? */
2402 if (cpustate >= state) 2402 if (cpustate >= state)
2403 cpuhp_issue_call(cpu, 2403 cpuhp_issue_call(cpu, state, false, node);
2404 } 2404 }
2405 } 2405 }
2406 2406
2407 int __cpuhp_state_add_instance_cpuslocked(enu 2407 int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state,
2408 str 2408 struct hlist_node *node,
2409 boo 2409 bool invoke)
2410 { 2410 {
2411 struct cpuhp_step *sp; 2411 struct cpuhp_step *sp;
2412 int cpu; 2412 int cpu;
2413 int ret; 2413 int ret;
2414 2414
2415 lockdep_assert_cpus_held(); 2415 lockdep_assert_cpus_held();
2416 2416
2417 sp = cpuhp_get_step(state); 2417 sp = cpuhp_get_step(state);
2418 if (sp->multi_instance == false) 2418 if (sp->multi_instance == false)
2419 return -EINVAL; 2419 return -EINVAL;
2420 2420
2421 mutex_lock(&cpuhp_state_mutex); 2421 mutex_lock(&cpuhp_state_mutex);
2422 2422
2423 if (!invoke || !sp->startup.multi) 2423 if (!invoke || !sp->startup.multi)
2424 goto add_node; 2424 goto add_node;
2425 2425
2426 /* 2426 /*
2427 * Try to call the startup callback f 2427 * Try to call the startup callback for each present cpu
2428 * depending on the hotplug state of 2428 * depending on the hotplug state of the cpu.
2429 */ 2429 */
2430 for_each_present_cpu(cpu) { 2430 for_each_present_cpu(cpu) {
2431 struct cpuhp_cpu_state *st = 2431 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2432 int cpustate = st->state; 2432 int cpustate = st->state;
2433 2433
2434 if (cpustate < state) 2434 if (cpustate < state)
2435 continue; 2435 continue;
2436 2436
2437 ret = cpuhp_issue_call(cpu, s 2437 ret = cpuhp_issue_call(cpu, state, true, node);
2438 if (ret) { 2438 if (ret) {
2439 if (sp->teardown.mult 2439 if (sp->teardown.multi)
2440 cpuhp_rollbac 2440 cpuhp_rollback_install(cpu, state, node);
2441 goto unlock; 2441 goto unlock;
2442 } 2442 }
2443 } 2443 }
2444 add_node: 2444 add_node:
2445 ret = 0; 2445 ret = 0;
2446 hlist_add_head(node, &sp->list); 2446 hlist_add_head(node, &sp->list);
2447 unlock: 2447 unlock:
2448 mutex_unlock(&cpuhp_state_mutex); 2448 mutex_unlock(&cpuhp_state_mutex);
2449 return ret; 2449 return ret;
2450 } 2450 }
2451 2451
2452 int __cpuhp_state_add_instance(enum cpuhp_sta 2452 int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node,
2453 bool invoke) 2453 bool invoke)
2454 { 2454 {
2455 int ret; 2455 int ret;
2456 2456
2457 cpus_read_lock(); 2457 cpus_read_lock();
2458 ret = __cpuhp_state_add_instance_cpus 2458 ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke);
2459 cpus_read_unlock(); 2459 cpus_read_unlock();
2460 return ret; 2460 return ret;
2461 } 2461 }
2462 EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance) 2462 EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance);
2463 2463
2464 /** 2464 /**
2465 * __cpuhp_setup_state_cpuslocked - Setup the 2465 * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state
2466 * @state: The state to setup 2466 * @state: The state to setup
2467 * @name: Name of the step 2467 * @name: Name of the step
2468 * @invoke: If true, the startup 2468 * @invoke: If true, the startup function is invoked for cpus where
2469 * cpu state >= @state 2469 * cpu state >= @state
2470 * @startup: startup callback func 2470 * @startup: startup callback function
2471 * @teardown: teardown callback fun 2471 * @teardown: teardown callback function
2472 * @multi_instance: State is set up for m 2472 * @multi_instance: State is set up for multiple instances which get
2473 * added afterwards. 2473 * added afterwards.
2474 * 2474 *
2475 * The caller needs to hold cpus read locked 2475 * The caller needs to hold cpus read locked while calling this function.
2476 * Return: 2476 * Return:
2477 * On success: 2477 * On success:
2478 * Positive state number if @state is CP 2478 * Positive state number if @state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN;
2479 * 0 for all other states 2479 * 0 for all other states
2480 * On failure: proper (negative) error code 2480 * On failure: proper (negative) error code
2481 */ 2481 */
2482 int __cpuhp_setup_state_cpuslocked(enum cpuhp 2482 int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state,
2483 const char 2483 const char *name, bool invoke,
2484 int (*star 2484 int (*startup)(unsigned int cpu),
2485 int (*tear 2485 int (*teardown)(unsigned int cpu),
2486 bool multi 2486 bool multi_instance)
2487 { 2487 {
2488 int cpu, ret = 0; 2488 int cpu, ret = 0;
2489 bool dynstate; 2489 bool dynstate;
2490 2490
2491 lockdep_assert_cpus_held(); 2491 lockdep_assert_cpus_held();
2492 2492
2493 if (cpuhp_cb_check(state) || !name) 2493 if (cpuhp_cb_check(state) || !name)
2494 return -EINVAL; 2494 return -EINVAL;
2495 2495
2496 mutex_lock(&cpuhp_state_mutex); 2496 mutex_lock(&cpuhp_state_mutex);
2497 2497
2498 ret = cpuhp_store_callbacks(state, na 2498 ret = cpuhp_store_callbacks(state, name, startup, teardown,
2499 multi_ins 2499 multi_instance);
2500 2500
2501 dynstate = state == CPUHP_AP_ONLINE_D 2501 dynstate = state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN;
2502 if (ret > 0 && dynstate) { 2502 if (ret > 0 && dynstate) {
2503 state = ret; 2503 state = ret;
2504 ret = 0; 2504 ret = 0;
2505 } 2505 }
2506 2506
2507 if (ret || !invoke || !startup) 2507 if (ret || !invoke || !startup)
2508 goto out; 2508 goto out;
2509 2509
2510 /* 2510 /*
2511 * Try to call the startup callback f 2511 * Try to call the startup callback for each present cpu
2512 * depending on the hotplug state of 2512 * depending on the hotplug state of the cpu.
2513 */ 2513 */
2514 for_each_present_cpu(cpu) { 2514 for_each_present_cpu(cpu) {
2515 struct cpuhp_cpu_state *st = 2515 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2516 int cpustate = st->state; 2516 int cpustate = st->state;
2517 2517
2518 if (cpustate < state) 2518 if (cpustate < state)
2519 continue; 2519 continue;
2520 2520
2521 ret = cpuhp_issue_call(cpu, s 2521 ret = cpuhp_issue_call(cpu, state, true, NULL);
2522 if (ret) { 2522 if (ret) {
2523 if (teardown) 2523 if (teardown)
2524 cpuhp_rollbac 2524 cpuhp_rollback_install(cpu, state, NULL);
2525 cpuhp_store_callbacks 2525 cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
2526 goto out; 2526 goto out;
2527 } 2527 }
2528 } 2528 }
2529 out: 2529 out:
2530 mutex_unlock(&cpuhp_state_mutex); 2530 mutex_unlock(&cpuhp_state_mutex);
2531 /* 2531 /*
2532 * If the requested state is CPUHP_AP 2532 * If the requested state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN,
2533 * return the dynamically allocated s 2533 * return the dynamically allocated state in case of success.
2534 */ 2534 */
2535 if (!ret && dynstate) 2535 if (!ret && dynstate)
2536 return state; 2536 return state;
2537 return ret; 2537 return ret;
2538 } 2538 }
2539 EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked) 2539 EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked);
2540 2540
2541 int __cpuhp_setup_state(enum cpuhp_state stat 2541 int __cpuhp_setup_state(enum cpuhp_state state,
2542 const char *name, boo 2542 const char *name, bool invoke,
2543 int (*startup)(unsign 2543 int (*startup)(unsigned int cpu),
2544 int (*teardown)(unsig 2544 int (*teardown)(unsigned int cpu),
2545 bool multi_instance) 2545 bool multi_instance)
2546 { 2546 {
2547 int ret; 2547 int ret;
2548 2548
2549 cpus_read_lock(); 2549 cpus_read_lock();
2550 ret = __cpuhp_setup_state_cpuslocked( 2550 ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup,
2551 2551 teardown, multi_instance);
2552 cpus_read_unlock(); 2552 cpus_read_unlock();
2553 return ret; 2553 return ret;
2554 } 2554 }
2555 EXPORT_SYMBOL(__cpuhp_setup_state); 2555 EXPORT_SYMBOL(__cpuhp_setup_state);
2556 2556
2557 int __cpuhp_state_remove_instance(enum cpuhp_ 2557 int __cpuhp_state_remove_instance(enum cpuhp_state state,
2558 struct hlis 2558 struct hlist_node *node, bool invoke)
2559 { 2559 {
2560 struct cpuhp_step *sp = cpuhp_get_ste 2560 struct cpuhp_step *sp = cpuhp_get_step(state);
2561 int cpu; 2561 int cpu;
2562 2562
2563 BUG_ON(cpuhp_cb_check(state)); 2563 BUG_ON(cpuhp_cb_check(state));
2564 2564
2565 if (!sp->multi_instance) 2565 if (!sp->multi_instance)
2566 return -EINVAL; 2566 return -EINVAL;
2567 2567
2568 cpus_read_lock(); 2568 cpus_read_lock();
2569 mutex_lock(&cpuhp_state_mutex); 2569 mutex_lock(&cpuhp_state_mutex);
2570 2570
2571 if (!invoke || !cpuhp_get_teardown_cb 2571 if (!invoke || !cpuhp_get_teardown_cb(state))
2572 goto remove; 2572 goto remove;
2573 /* 2573 /*
2574 * Call the teardown callback for eac 2574 * Call the teardown callback for each present cpu depending
2575 * on the hotplug state of the cpu. T 2575 * on the hotplug state of the cpu. This function is not
2576 * allowed to fail currently! 2576 * allowed to fail currently!
2577 */ 2577 */
2578 for_each_present_cpu(cpu) { 2578 for_each_present_cpu(cpu) {
2579 struct cpuhp_cpu_state *st = 2579 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2580 int cpustate = st->state; 2580 int cpustate = st->state;
2581 2581
2582 if (cpustate >= state) 2582 if (cpustate >= state)
2583 cpuhp_issue_call(cpu, 2583 cpuhp_issue_call(cpu, state, false, node);
2584 } 2584 }
2585 2585
2586 remove: 2586 remove:
2587 hlist_del(node); 2587 hlist_del(node);
2588 mutex_unlock(&cpuhp_state_mutex); 2588 mutex_unlock(&cpuhp_state_mutex);
2589 cpus_read_unlock(); 2589 cpus_read_unlock();
2590 2590
2591 return 0; 2591 return 0;
2592 } 2592 }
2593 EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instan 2593 EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance);
2594 2594
2595 /** 2595 /**
2596 * __cpuhp_remove_state_cpuslocked - Remove t 2596 * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state
2597 * @state: The state to remove 2597 * @state: The state to remove
2598 * @invoke: If true, the teardown functio 2598 * @invoke: If true, the teardown function is invoked for cpus where
2599 * cpu state >= @state 2599 * cpu state >= @state
2600 * 2600 *
2601 * The caller needs to hold cpus read locked 2601 * The caller needs to hold cpus read locked while calling this function.
2602 * The teardown callback is currently not all 2602 * The teardown callback is currently not allowed to fail. Think
2603 * about module removal! 2603 * about module removal!
2604 */ 2604 */
2605 void __cpuhp_remove_state_cpuslocked(enum cpu 2605 void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke)
2606 { 2606 {
2607 struct cpuhp_step *sp = cpuhp_get_ste 2607 struct cpuhp_step *sp = cpuhp_get_step(state);
2608 int cpu; 2608 int cpu;
2609 2609
2610 BUG_ON(cpuhp_cb_check(state)); 2610 BUG_ON(cpuhp_cb_check(state));
2611 2611
2612 lockdep_assert_cpus_held(); 2612 lockdep_assert_cpus_held();
2613 2613
2614 mutex_lock(&cpuhp_state_mutex); 2614 mutex_lock(&cpuhp_state_mutex);
2615 if (sp->multi_instance) { 2615 if (sp->multi_instance) {
2616 WARN(!hlist_empty(&sp->list), 2616 WARN(!hlist_empty(&sp->list),
2617 "Error: Removing state % 2617 "Error: Removing state %d which has instances left.\n",
2618 state); 2618 state);
2619 goto remove; 2619 goto remove;
2620 } 2620 }
2621 2621
2622 if (!invoke || !cpuhp_get_teardown_cb 2622 if (!invoke || !cpuhp_get_teardown_cb(state))
2623 goto remove; 2623 goto remove;
2624 2624
2625 /* 2625 /*
2626 * Call the teardown callback for eac 2626 * Call the teardown callback for each present cpu depending
2627 * on the hotplug state of the cpu. T 2627 * on the hotplug state of the cpu. This function is not
2628 * allowed to fail currently! 2628 * allowed to fail currently!
2629 */ 2629 */
2630 for_each_present_cpu(cpu) { 2630 for_each_present_cpu(cpu) {
2631 struct cpuhp_cpu_state *st = 2631 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
2632 int cpustate = st->state; 2632 int cpustate = st->state;
2633 2633
2634 if (cpustate >= state) 2634 if (cpustate >= state)
2635 cpuhp_issue_call(cpu, 2635 cpuhp_issue_call(cpu, state, false, NULL);
2636 } 2636 }
2637 remove: 2637 remove:
2638 cpuhp_store_callbacks(state, NULL, NU 2638 cpuhp_store_callbacks(state, NULL, NULL, NULL, false);
2639 mutex_unlock(&cpuhp_state_mutex); 2639 mutex_unlock(&cpuhp_state_mutex);
2640 } 2640 }
2641 EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked 2641 EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked);
2642 2642
2643 void __cpuhp_remove_state(enum cpuhp_state st 2643 void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
2644 { 2644 {
2645 cpus_read_lock(); 2645 cpus_read_lock();
2646 __cpuhp_remove_state_cpuslocked(state 2646 __cpuhp_remove_state_cpuslocked(state, invoke);
2647 cpus_read_unlock(); 2647 cpus_read_unlock();
2648 } 2648 }
2649 EXPORT_SYMBOL(__cpuhp_remove_state); 2649 EXPORT_SYMBOL(__cpuhp_remove_state);
2650 2650
2651 #ifdef CONFIG_HOTPLUG_SMT 2651 #ifdef CONFIG_HOTPLUG_SMT
2652 static void cpuhp_offline_cpu_device(unsigned 2652 static void cpuhp_offline_cpu_device(unsigned int cpu)
2653 { 2653 {
2654 struct device *dev = get_cpu_device(c 2654 struct device *dev = get_cpu_device(cpu);
2655 2655
2656 dev->offline = true; 2656 dev->offline = true;
2657 /* Tell user space about the state ch 2657 /* Tell user space about the state change */
2658 kobject_uevent(&dev->kobj, KOBJ_OFFLI 2658 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
2659 } 2659 }
2660 2660
2661 static void cpuhp_online_cpu_device(unsigned 2661 static void cpuhp_online_cpu_device(unsigned int cpu)
2662 { 2662 {
2663 struct device *dev = get_cpu_device(c 2663 struct device *dev = get_cpu_device(cpu);
2664 2664
2665 dev->offline = false; 2665 dev->offline = false;
2666 /* Tell user space about the state ch 2666 /* Tell user space about the state change */
2667 kobject_uevent(&dev->kobj, KOBJ_ONLIN 2667 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
2668 } 2668 }
2669 2669
2670 int cpuhp_smt_disable(enum cpuhp_smt_control 2670 int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
2671 { 2671 {
2672 int cpu, ret = 0; 2672 int cpu, ret = 0;
2673 2673
2674 cpu_maps_update_begin(); 2674 cpu_maps_update_begin();
2675 for_each_online_cpu(cpu) { 2675 for_each_online_cpu(cpu) {
2676 if (topology_is_primary_threa 2676 if (topology_is_primary_thread(cpu))
2677 continue; 2677 continue;
2678 /* 2678 /*
2679 * Disable can be called with 2679 * Disable can be called with CPU_SMT_ENABLED when changing
2680 * from a higher to lower num 2680 * from a higher to lower number of SMT threads per core.
2681 */ 2681 */
2682 if (ctrlval == CPU_SMT_ENABLE 2682 if (ctrlval == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
2683 continue; 2683 continue;
2684 ret = cpu_down_maps_locked(cp 2684 ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
2685 if (ret) 2685 if (ret)
2686 break; 2686 break;
2687 /* 2687 /*
2688 * As this needs to hold the 2688 * As this needs to hold the cpu maps lock it's impossible
2689 * to call device_offline() b 2689 * to call device_offline() because that ends up calling
2690 * cpu_down() which takes cpu 2690 * cpu_down() which takes cpu maps lock. cpu maps lock
2691 * needs to be held as this m 2691 * needs to be held as this might race against in kernel
2692 * abusers of the hotplug mac 2692 * abusers of the hotplug machinery (thermal management).
2693 * 2693 *
2694 * So nothing would update de 2694 * So nothing would update device:offline state. That would
2695 * leave the sysfs entry stal 2695 * leave the sysfs entry stale and prevent onlining after
2696 * smt control has been chang 2696 * smt control has been changed to 'off' again. This is
2697 * called under the sysfs hot 2697 * called under the sysfs hotplug lock, so it is properly
2698 * serialized against the reg 2698 * serialized against the regular offline usage.
2699 */ 2699 */
2700 cpuhp_offline_cpu_device(cpu) 2700 cpuhp_offline_cpu_device(cpu);
2701 } 2701 }
2702 if (!ret) 2702 if (!ret)
2703 cpu_smt_control = ctrlval; 2703 cpu_smt_control = ctrlval;
2704 cpu_maps_update_done(); 2704 cpu_maps_update_done();
2705 return ret; 2705 return ret;
2706 } 2706 }
2707 2707
2708 /* Check if the core a CPU belongs to is onli 2708 /* Check if the core a CPU belongs to is online */
2709 #if !defined(topology_is_core_online) 2709 #if !defined(topology_is_core_online)
2710 static inline bool topology_is_core_online(un 2710 static inline bool topology_is_core_online(unsigned int cpu)
2711 { 2711 {
2712 return true; 2712 return true;
2713 } 2713 }
2714 #endif 2714 #endif
2715 2715
2716 int cpuhp_smt_enable(void) 2716 int cpuhp_smt_enable(void)
2717 { 2717 {
2718 int cpu, ret = 0; 2718 int cpu, ret = 0;
2719 2719
2720 cpu_maps_update_begin(); 2720 cpu_maps_update_begin();
2721 cpu_smt_control = CPU_SMT_ENABLED; 2721 cpu_smt_control = CPU_SMT_ENABLED;
2722 for_each_present_cpu(cpu) { 2722 for_each_present_cpu(cpu) {
2723 /* Skip online CPUs and CPUs 2723 /* Skip online CPUs and CPUs on offline nodes */
2724 if (cpu_online(cpu) || !node_ 2724 if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
2725 continue; 2725 continue;
2726 if (!cpu_smt_thread_allowed(c 2726 if (!cpu_smt_thread_allowed(cpu) || !topology_is_core_online(cpu))
2727 continue; 2727 continue;
2728 ret = _cpu_up(cpu, 0, CPUHP_O 2728 ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
2729 if (ret) 2729 if (ret)
2730 break; 2730 break;
2731 /* See comment in cpuhp_smt_d 2731 /* See comment in cpuhp_smt_disable() */
2732 cpuhp_online_cpu_device(cpu); 2732 cpuhp_online_cpu_device(cpu);
2733 } 2733 }
2734 cpu_maps_update_done(); 2734 cpu_maps_update_done();
2735 return ret; 2735 return ret;
2736 } 2736 }
2737 #endif 2737 #endif
2738 2738
2739 #if defined(CONFIG_SYSFS) && defined(CONFIG_H 2739 #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
2740 static ssize_t state_show(struct device *dev, 2740 static ssize_t state_show(struct device *dev,
2741 struct device_attri 2741 struct device_attribute *attr, char *buf)
2742 { 2742 {
2743 struct cpuhp_cpu_state *st = per_cpu_ 2743 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2744 2744
2745 return sprintf(buf, "%d\n", st->state 2745 return sprintf(buf, "%d\n", st->state);
2746 } 2746 }
2747 static DEVICE_ATTR_RO(state); 2747 static DEVICE_ATTR_RO(state);
2748 2748
2749 static ssize_t target_store(struct device *de 2749 static ssize_t target_store(struct device *dev, struct device_attribute *attr,
2750 const char *buf, 2750 const char *buf, size_t count)
2751 { 2751 {
2752 struct cpuhp_cpu_state *st = per_cpu_ 2752 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2753 struct cpuhp_step *sp; 2753 struct cpuhp_step *sp;
2754 int target, ret; 2754 int target, ret;
2755 2755
2756 ret = kstrtoint(buf, 10, &target); 2756 ret = kstrtoint(buf, 10, &target);
2757 if (ret) 2757 if (ret)
2758 return ret; 2758 return ret;
2759 2759
2760 #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL 2760 #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL
2761 if (target < CPUHP_OFFLINE || target 2761 if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE)
2762 return -EINVAL; 2762 return -EINVAL;
2763 #else 2763 #else
2764 if (target != CPUHP_OFFLINE && target 2764 if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE)
2765 return -EINVAL; 2765 return -EINVAL;
2766 #endif 2766 #endif
2767 2767
2768 ret = lock_device_hotplug_sysfs(); 2768 ret = lock_device_hotplug_sysfs();
2769 if (ret) 2769 if (ret)
2770 return ret; 2770 return ret;
2771 2771
2772 mutex_lock(&cpuhp_state_mutex); 2772 mutex_lock(&cpuhp_state_mutex);
2773 sp = cpuhp_get_step(target); 2773 sp = cpuhp_get_step(target);
2774 ret = !sp->name || sp->cant_stop ? -E 2774 ret = !sp->name || sp->cant_stop ? -EINVAL : 0;
2775 mutex_unlock(&cpuhp_state_mutex); 2775 mutex_unlock(&cpuhp_state_mutex);
2776 if (ret) 2776 if (ret)
2777 goto out; 2777 goto out;
2778 2778
2779 if (st->state < target) 2779 if (st->state < target)
2780 ret = cpu_up(dev->id, target) 2780 ret = cpu_up(dev->id, target);
2781 else if (st->state > target) 2781 else if (st->state > target)
2782 ret = cpu_down(dev->id, targe 2782 ret = cpu_down(dev->id, target);
2783 else if (WARN_ON(st->target != target 2783 else if (WARN_ON(st->target != target))
2784 st->target = target; 2784 st->target = target;
2785 out: 2785 out:
2786 unlock_device_hotplug(); 2786 unlock_device_hotplug();
2787 return ret ? ret : count; 2787 return ret ? ret : count;
2788 } 2788 }
2789 2789
2790 static ssize_t target_show(struct device *dev 2790 static ssize_t target_show(struct device *dev,
2791 struct device_attr 2791 struct device_attribute *attr, char *buf)
2792 { 2792 {
2793 struct cpuhp_cpu_state *st = per_cpu_ 2793 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2794 2794
2795 return sprintf(buf, "%d\n", st->targe 2795 return sprintf(buf, "%d\n", st->target);
2796 } 2796 }
2797 static DEVICE_ATTR_RW(target); 2797 static DEVICE_ATTR_RW(target);
2798 2798
2799 static ssize_t fail_store(struct device *dev, 2799 static ssize_t fail_store(struct device *dev, struct device_attribute *attr,
2800 const char *buf, si 2800 const char *buf, size_t count)
2801 { 2801 {
2802 struct cpuhp_cpu_state *st = per_cpu_ 2802 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2803 struct cpuhp_step *sp; 2803 struct cpuhp_step *sp;
2804 int fail, ret; 2804 int fail, ret;
2805 2805
2806 ret = kstrtoint(buf, 10, &fail); 2806 ret = kstrtoint(buf, 10, &fail);
2807 if (ret) 2807 if (ret)
2808 return ret; 2808 return ret;
2809 2809
2810 if (fail == CPUHP_INVALID) { 2810 if (fail == CPUHP_INVALID) {
2811 st->fail = fail; 2811 st->fail = fail;
2812 return count; 2812 return count;
2813 } 2813 }
2814 2814
2815 if (fail < CPUHP_OFFLINE || fail > CP 2815 if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE)
2816 return -EINVAL; 2816 return -EINVAL;
2817 2817
2818 /* 2818 /*
2819 * Cannot fail STARTING/DYING callbac 2819 * Cannot fail STARTING/DYING callbacks.
2820 */ 2820 */
2821 if (cpuhp_is_atomic_state(fail)) 2821 if (cpuhp_is_atomic_state(fail))
2822 return -EINVAL; 2822 return -EINVAL;
2823 2823
2824 /* 2824 /*
2825 * DEAD callbacks cannot fail... 2825 * DEAD callbacks cannot fail...
2826 * ... neither can CPUHP_BRINGUP_CPU 2826 * ... neither can CPUHP_BRINGUP_CPU during hotunplug. The latter
2827 * triggering STARTING callbacks, a f 2827 * triggering STARTING callbacks, a failure in this state would
2828 * hinder rollback. 2828 * hinder rollback.
2829 */ 2829 */
2830 if (fail <= CPUHP_BRINGUP_CPU && st-> 2830 if (fail <= CPUHP_BRINGUP_CPU && st->state > CPUHP_BRINGUP_CPU)
2831 return -EINVAL; 2831 return -EINVAL;
2832 2832
2833 /* 2833 /*
2834 * Cannot fail anything that doesn't 2834 * Cannot fail anything that doesn't have callbacks.
2835 */ 2835 */
2836 mutex_lock(&cpuhp_state_mutex); 2836 mutex_lock(&cpuhp_state_mutex);
2837 sp = cpuhp_get_step(fail); 2837 sp = cpuhp_get_step(fail);
2838 if (!sp->startup.single && !sp->teard 2838 if (!sp->startup.single && !sp->teardown.single)
2839 ret = -EINVAL; 2839 ret = -EINVAL;
2840 mutex_unlock(&cpuhp_state_mutex); 2840 mutex_unlock(&cpuhp_state_mutex);
2841 if (ret) 2841 if (ret)
2842 return ret; 2842 return ret;
2843 2843
2844 st->fail = fail; 2844 st->fail = fail;
2845 2845
2846 return count; 2846 return count;
2847 } 2847 }
2848 2848
2849 static ssize_t fail_show(struct device *dev, 2849 static ssize_t fail_show(struct device *dev,
2850 struct device_attrib 2850 struct device_attribute *attr, char *buf)
2851 { 2851 {
2852 struct cpuhp_cpu_state *st = per_cpu_ 2852 struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id);
2853 2853
2854 return sprintf(buf, "%d\n", st->fail) 2854 return sprintf(buf, "%d\n", st->fail);
2855 } 2855 }
2856 2856
2857 static DEVICE_ATTR_RW(fail); 2857 static DEVICE_ATTR_RW(fail);
2858 2858
2859 static struct attribute *cpuhp_cpu_attrs[] = 2859 static struct attribute *cpuhp_cpu_attrs[] = {
2860 &dev_attr_state.attr, 2860 &dev_attr_state.attr,
2861 &dev_attr_target.attr, 2861 &dev_attr_target.attr,
2862 &dev_attr_fail.attr, 2862 &dev_attr_fail.attr,
2863 NULL 2863 NULL
2864 }; 2864 };
2865 2865
2866 static const struct attribute_group cpuhp_cpu 2866 static const struct attribute_group cpuhp_cpu_attr_group = {
2867 .attrs = cpuhp_cpu_attrs, 2867 .attrs = cpuhp_cpu_attrs,
2868 .name = "hotplug", 2868 .name = "hotplug",
2869 NULL 2869 NULL
2870 }; 2870 };
2871 2871
2872 static ssize_t states_show(struct device *dev 2872 static ssize_t states_show(struct device *dev,
2873 struct devic 2873 struct device_attribute *attr, char *buf)
2874 { 2874 {
2875 ssize_t cur, res = 0; 2875 ssize_t cur, res = 0;
2876 int i; 2876 int i;
2877 2877
2878 mutex_lock(&cpuhp_state_mutex); 2878 mutex_lock(&cpuhp_state_mutex);
2879 for (i = CPUHP_OFFLINE; i <= CPUHP_ON 2879 for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) {
2880 struct cpuhp_step *sp = cpuhp 2880 struct cpuhp_step *sp = cpuhp_get_step(i);
2881 2881
2882 if (sp->name) { 2882 if (sp->name) {
2883 cur = sprintf(buf, "% 2883 cur = sprintf(buf, "%3d: %s\n", i, sp->name);
2884 buf += cur; 2884 buf += cur;
2885 res += cur; 2885 res += cur;
2886 } 2886 }
2887 } 2887 }
2888 mutex_unlock(&cpuhp_state_mutex); 2888 mutex_unlock(&cpuhp_state_mutex);
2889 return res; 2889 return res;
2890 } 2890 }
2891 static DEVICE_ATTR_RO(states); 2891 static DEVICE_ATTR_RO(states);
2892 2892
2893 static struct attribute *cpuhp_cpu_root_attrs 2893 static struct attribute *cpuhp_cpu_root_attrs[] = {
2894 &dev_attr_states.attr, 2894 &dev_attr_states.attr,
2895 NULL 2895 NULL
2896 }; 2896 };
2897 2897
2898 static const struct attribute_group cpuhp_cpu 2898 static const struct attribute_group cpuhp_cpu_root_attr_group = {
2899 .attrs = cpuhp_cpu_root_attrs, 2899 .attrs = cpuhp_cpu_root_attrs,
2900 .name = "hotplug", 2900 .name = "hotplug",
2901 NULL 2901 NULL
2902 }; 2902 };
2903 2903
2904 #ifdef CONFIG_HOTPLUG_SMT 2904 #ifdef CONFIG_HOTPLUG_SMT
2905 2905
2906 static bool cpu_smt_num_threads_valid(unsigne 2906 static bool cpu_smt_num_threads_valid(unsigned int threads)
2907 { 2907 {
2908 if (IS_ENABLED(CONFIG_SMT_NUM_THREADS 2908 if (IS_ENABLED(CONFIG_SMT_NUM_THREADS_DYNAMIC))
2909 return threads >= 1 && thread 2909 return threads >= 1 && threads <= cpu_smt_max_threads;
2910 return threads == 1 || threads == cpu 2910 return threads == 1 || threads == cpu_smt_max_threads;
2911 } 2911 }
2912 2912
2913 static ssize_t 2913 static ssize_t
2914 __store_smt_control(struct device *dev, struc 2914 __store_smt_control(struct device *dev, struct device_attribute *attr,
2915 const char *buf, size_t c 2915 const char *buf, size_t count)
2916 { 2916 {
2917 int ctrlval, ret, num_threads, orig_t 2917 int ctrlval, ret, num_threads, orig_threads;
2918 bool force_off; 2918 bool force_off;
2919 2919
2920 if (cpu_smt_control == CPU_SMT_FORCE_ 2920 if (cpu_smt_control == CPU_SMT_FORCE_DISABLED)
2921 return -EPERM; 2921 return -EPERM;
2922 2922
2923 if (cpu_smt_control == CPU_SMT_NOT_SU 2923 if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED)
2924 return -ENODEV; 2924 return -ENODEV;
2925 2925
2926 if (sysfs_streq(buf, "on")) { 2926 if (sysfs_streq(buf, "on")) {
2927 ctrlval = CPU_SMT_ENABLED; 2927 ctrlval = CPU_SMT_ENABLED;
2928 num_threads = cpu_smt_max_thr 2928 num_threads = cpu_smt_max_threads;
2929 } else if (sysfs_streq(buf, "off")) { 2929 } else if (sysfs_streq(buf, "off")) {
2930 ctrlval = CPU_SMT_DISABLED; 2930 ctrlval = CPU_SMT_DISABLED;
2931 num_threads = 1; 2931 num_threads = 1;
2932 } else if (sysfs_streq(buf, "forceoff 2932 } else if (sysfs_streq(buf, "forceoff")) {
2933 ctrlval = CPU_SMT_FORCE_DISAB 2933 ctrlval = CPU_SMT_FORCE_DISABLED;
2934 num_threads = 1; 2934 num_threads = 1;
2935 } else if (kstrtoint(buf, 10, &num_th 2935 } else if (kstrtoint(buf, 10, &num_threads) == 0) {
2936 if (num_threads == 1) 2936 if (num_threads == 1)
2937 ctrlval = CPU_SMT_DIS 2937 ctrlval = CPU_SMT_DISABLED;
2938 else if (cpu_smt_num_threads_ 2938 else if (cpu_smt_num_threads_valid(num_threads))
2939 ctrlval = CPU_SMT_ENA 2939 ctrlval = CPU_SMT_ENABLED;
2940 else 2940 else
2941 return -EINVAL; 2941 return -EINVAL;
2942 } else { 2942 } else {
2943 return -EINVAL; 2943 return -EINVAL;
2944 } 2944 }
2945 2945
2946 ret = lock_device_hotplug_sysfs(); 2946 ret = lock_device_hotplug_sysfs();
2947 if (ret) 2947 if (ret)
2948 return ret; 2948 return ret;
2949 2949
2950 orig_threads = cpu_smt_num_threads; 2950 orig_threads = cpu_smt_num_threads;
2951 cpu_smt_num_threads = num_threads; 2951 cpu_smt_num_threads = num_threads;
2952 2952
2953 force_off = ctrlval != cpu_smt_contro 2953 force_off = ctrlval != cpu_smt_control && ctrlval == CPU_SMT_FORCE_DISABLED;
2954 2954
2955 if (num_threads > orig_threads) 2955 if (num_threads > orig_threads)
2956 ret = cpuhp_smt_enable(); 2956 ret = cpuhp_smt_enable();
2957 else if (num_threads < orig_threads | 2957 else if (num_threads < orig_threads || force_off)
2958 ret = cpuhp_smt_disable(ctrlv 2958 ret = cpuhp_smt_disable(ctrlval);
2959 2959
2960 unlock_device_hotplug(); 2960 unlock_device_hotplug();
2961 return ret ? ret : count; 2961 return ret ? ret : count;
2962 } 2962 }
2963 2963
2964 #else /* !CONFIG_HOTPLUG_SMT */ 2964 #else /* !CONFIG_HOTPLUG_SMT */
2965 static ssize_t 2965 static ssize_t
2966 __store_smt_control(struct device *dev, struc 2966 __store_smt_control(struct device *dev, struct device_attribute *attr,
2967 const char *buf, size_t c 2967 const char *buf, size_t count)
2968 { 2968 {
2969 return -ENODEV; 2969 return -ENODEV;
2970 } 2970 }
2971 #endif /* CONFIG_HOTPLUG_SMT */ 2971 #endif /* CONFIG_HOTPLUG_SMT */
2972 2972
2973 static const char *smt_states[] = { 2973 static const char *smt_states[] = {
2974 [CPU_SMT_ENABLED] = "on 2974 [CPU_SMT_ENABLED] = "on",
2975 [CPU_SMT_DISABLED] = "of 2975 [CPU_SMT_DISABLED] = "off",
2976 [CPU_SMT_FORCE_DISABLED] = "fo 2976 [CPU_SMT_FORCE_DISABLED] = "forceoff",
2977 [CPU_SMT_NOT_SUPPORTED] = "no 2977 [CPU_SMT_NOT_SUPPORTED] = "notsupported",
2978 [CPU_SMT_NOT_IMPLEMENTED] = "no 2978 [CPU_SMT_NOT_IMPLEMENTED] = "notimplemented",
2979 }; 2979 };
2980 2980
2981 static ssize_t control_show(struct device *de 2981 static ssize_t control_show(struct device *dev,
2982 struct device_att 2982 struct device_attribute *attr, char *buf)
2983 { 2983 {
2984 const char *state = smt_states[cpu_sm 2984 const char *state = smt_states[cpu_smt_control];
2985 2985
2986 #ifdef CONFIG_HOTPLUG_SMT 2986 #ifdef CONFIG_HOTPLUG_SMT
2987 /* 2987 /*
2988 * If SMT is enabled but not all thre 2988 * If SMT is enabled but not all threads are enabled then show the
2989 * number of threads. If all threads 2989 * number of threads. If all threads are enabled show "on". Otherwise
2990 * show the state name. 2990 * show the state name.
2991 */ 2991 */
2992 if (cpu_smt_control == CPU_SMT_ENABLE 2992 if (cpu_smt_control == CPU_SMT_ENABLED &&
2993 cpu_smt_num_threads != cpu_smt_ma 2993 cpu_smt_num_threads != cpu_smt_max_threads)
2994 return sysfs_emit(buf, "%d\n" 2994 return sysfs_emit(buf, "%d\n", cpu_smt_num_threads);
2995 #endif 2995 #endif
2996 2996
2997 return sysfs_emit(buf, "%s\n", state) 2997 return sysfs_emit(buf, "%s\n", state);
2998 } 2998 }
2999 2999
3000 static ssize_t control_store(struct device *d 3000 static ssize_t control_store(struct device *dev, struct device_attribute *attr,
3001 const char *buf, 3001 const char *buf, size_t count)
3002 { 3002 {
3003 return __store_smt_control(dev, attr, 3003 return __store_smt_control(dev, attr, buf, count);
3004 } 3004 }
3005 static DEVICE_ATTR_RW(control); 3005 static DEVICE_ATTR_RW(control);
3006 3006
3007 static ssize_t active_show(struct device *dev 3007 static ssize_t active_show(struct device *dev,
3008 struct device_attr 3008 struct device_attribute *attr, char *buf)
3009 { 3009 {
3010 return sysfs_emit(buf, "%d\n", sched_ 3010 return sysfs_emit(buf, "%d\n", sched_smt_active());
3011 } 3011 }
3012 static DEVICE_ATTR_RO(active); 3012 static DEVICE_ATTR_RO(active);
3013 3013
3014 static struct attribute *cpuhp_smt_attrs[] = 3014 static struct attribute *cpuhp_smt_attrs[] = {
3015 &dev_attr_control.attr, 3015 &dev_attr_control.attr,
3016 &dev_attr_active.attr, 3016 &dev_attr_active.attr,
3017 NULL 3017 NULL
3018 }; 3018 };
3019 3019
3020 static const struct attribute_group cpuhp_smt 3020 static const struct attribute_group cpuhp_smt_attr_group = {
3021 .attrs = cpuhp_smt_attrs, 3021 .attrs = cpuhp_smt_attrs,
3022 .name = "smt", 3022 .name = "smt",
3023 NULL 3023 NULL
3024 }; 3024 };
3025 3025
3026 static int __init cpu_smt_sysfs_init(void) 3026 static int __init cpu_smt_sysfs_init(void)
3027 { 3027 {
3028 struct device *dev_root; 3028 struct device *dev_root;
3029 int ret = -ENODEV; 3029 int ret = -ENODEV;
3030 3030
3031 dev_root = bus_get_dev_root(&cpu_subs 3031 dev_root = bus_get_dev_root(&cpu_subsys);
3032 if (dev_root) { 3032 if (dev_root) {
3033 ret = sysfs_create_group(&dev 3033 ret = sysfs_create_group(&dev_root->kobj, &cpuhp_smt_attr_group);
3034 put_device(dev_root); 3034 put_device(dev_root);
3035 } 3035 }
3036 return ret; 3036 return ret;
3037 } 3037 }
3038 3038
3039 static int __init cpuhp_sysfs_init(void) 3039 static int __init cpuhp_sysfs_init(void)
3040 { 3040 {
3041 struct device *dev_root; 3041 struct device *dev_root;
3042 int cpu, ret; 3042 int cpu, ret;
3043 3043
3044 ret = cpu_smt_sysfs_init(); 3044 ret = cpu_smt_sysfs_init();
3045 if (ret) 3045 if (ret)
3046 return ret; 3046 return ret;
3047 3047
3048 dev_root = bus_get_dev_root(&cpu_subs 3048 dev_root = bus_get_dev_root(&cpu_subsys);
3049 if (dev_root) { 3049 if (dev_root) {
3050 ret = sysfs_create_group(&dev 3050 ret = sysfs_create_group(&dev_root->kobj, &cpuhp_cpu_root_attr_group);
3051 put_device(dev_root); 3051 put_device(dev_root);
3052 if (ret) 3052 if (ret)
3053 return ret; 3053 return ret;
3054 } 3054 }
3055 3055
3056 for_each_possible_cpu(cpu) { 3056 for_each_possible_cpu(cpu) {
3057 struct device *dev = get_cpu_ 3057 struct device *dev = get_cpu_device(cpu);
3058 3058
3059 if (!dev) 3059 if (!dev)
3060 continue; 3060 continue;
3061 ret = sysfs_create_group(&dev 3061 ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group);
3062 if (ret) 3062 if (ret)
3063 return ret; 3063 return ret;
3064 } 3064 }
3065 return 0; 3065 return 0;
3066 } 3066 }
3067 device_initcall(cpuhp_sysfs_init); 3067 device_initcall(cpuhp_sysfs_init);
3068 #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU 3068 #endif /* CONFIG_SYSFS && CONFIG_HOTPLUG_CPU */
3069 3069
3070 /* 3070 /*
3071 * cpu_bit_bitmap[] is a special, "compressed 3071 * cpu_bit_bitmap[] is a special, "compressed" data structure that
3072 * represents all NR_CPUS bits binary values 3072 * represents all NR_CPUS bits binary values of 1<<nr.
3073 * 3073 *
3074 * It is used by cpumask_of() to get a consta 3074 * It is used by cpumask_of() to get a constant address to a CPU
3075 * mask value that has a single bit set only. 3075 * mask value that has a single bit set only.
3076 */ 3076 */
3077 3077
3078 /* cpu_bit_bitmap[0] is empty - so we can bac 3078 /* cpu_bit_bitmap[0] is empty - so we can back into it */
3079 #define MASK_DECLARE_1(x) [x+1][0] = (1 3079 #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x))
3080 #define MASK_DECLARE_2(x) MASK_DECLARE_ 3080 #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1)
3081 #define MASK_DECLARE_4(x) MASK_DECLARE_ 3081 #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2)
3082 #define MASK_DECLARE_8(x) MASK_DECLARE_ 3082 #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4)
3083 3083
3084 const unsigned long cpu_bit_bitmap[BITS_PER_L 3084 const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = {
3085 3085
3086 MASK_DECLARE_8(0), MASK_DECLARE_ 3086 MASK_DECLARE_8(0), MASK_DECLARE_8(8),
3087 MASK_DECLARE_8(16), MASK_DECLARE_ 3087 MASK_DECLARE_8(16), MASK_DECLARE_8(24),
3088 #if BITS_PER_LONG > 32 3088 #if BITS_PER_LONG > 32
3089 MASK_DECLARE_8(32), MASK_DECLARE_ 3089 MASK_DECLARE_8(32), MASK_DECLARE_8(40),
3090 MASK_DECLARE_8(48), MASK_DECLARE_ 3090 MASK_DECLARE_8(48), MASK_DECLARE_8(56),
3091 #endif 3091 #endif
3092 }; 3092 };
3093 EXPORT_SYMBOL_GPL(cpu_bit_bitmap); 3093 EXPORT_SYMBOL_GPL(cpu_bit_bitmap);
3094 3094
3095 const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = 3095 const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL;
3096 EXPORT_SYMBOL(cpu_all_bits); 3096 EXPORT_SYMBOL(cpu_all_bits);
3097 3097
3098 #ifdef CONFIG_INIT_ALL_POSSIBLE 3098 #ifdef CONFIG_INIT_ALL_POSSIBLE
3099 struct cpumask __cpu_possible_mask __ro_after 3099 struct cpumask __cpu_possible_mask __ro_after_init
3100 = {CPU_BITS_ALL}; 3100 = {CPU_BITS_ALL};
3101 #else 3101 #else
3102 struct cpumask __cpu_possible_mask __ro_after 3102 struct cpumask __cpu_possible_mask __ro_after_init;
3103 #endif 3103 #endif
3104 EXPORT_SYMBOL(__cpu_possible_mask); 3104 EXPORT_SYMBOL(__cpu_possible_mask);
3105 3105
3106 struct cpumask __cpu_online_mask __read_mostl 3106 struct cpumask __cpu_online_mask __read_mostly;
3107 EXPORT_SYMBOL(__cpu_online_mask); 3107 EXPORT_SYMBOL(__cpu_online_mask);
3108 3108
3109 struct cpumask __cpu_enabled_mask __read_most 3109 struct cpumask __cpu_enabled_mask __read_mostly;
3110 EXPORT_SYMBOL(__cpu_enabled_mask); 3110 EXPORT_SYMBOL(__cpu_enabled_mask);
3111 3111
3112 struct cpumask __cpu_present_mask __read_most 3112 struct cpumask __cpu_present_mask __read_mostly;
3113 EXPORT_SYMBOL(__cpu_present_mask); 3113 EXPORT_SYMBOL(__cpu_present_mask);
3114 3114
3115 struct cpumask __cpu_active_mask __read_mostl 3115 struct cpumask __cpu_active_mask __read_mostly;
3116 EXPORT_SYMBOL(__cpu_active_mask); 3116 EXPORT_SYMBOL(__cpu_active_mask);
3117 3117
3118 struct cpumask __cpu_dying_mask __read_mostly 3118 struct cpumask __cpu_dying_mask __read_mostly;
3119 EXPORT_SYMBOL(__cpu_dying_mask); 3119 EXPORT_SYMBOL(__cpu_dying_mask);
3120 3120
3121 atomic_t __num_online_cpus __read_mostly; 3121 atomic_t __num_online_cpus __read_mostly;
3122 EXPORT_SYMBOL(__num_online_cpus); 3122 EXPORT_SYMBOL(__num_online_cpus);
3123 3123
3124 void init_cpu_present(const struct cpumask *s 3124 void init_cpu_present(const struct cpumask *src)
3125 { 3125 {
3126 cpumask_copy(&__cpu_present_mask, src 3126 cpumask_copy(&__cpu_present_mask, src);
3127 } 3127 }
3128 3128
3129 void init_cpu_possible(const struct cpumask * 3129 void init_cpu_possible(const struct cpumask *src)
3130 { 3130 {
3131 cpumask_copy(&__cpu_possible_mask, sr 3131 cpumask_copy(&__cpu_possible_mask, src);
3132 } 3132 }
3133 3133
3134 void init_cpu_online(const struct cpumask *sr 3134 void init_cpu_online(const struct cpumask *src)
3135 { 3135 {
3136 cpumask_copy(&__cpu_online_mask, src) 3136 cpumask_copy(&__cpu_online_mask, src);
3137 } 3137 }
3138 3138
3139 void set_cpu_online(unsigned int cpu, bool on 3139 void set_cpu_online(unsigned int cpu, bool online)
3140 { 3140 {
3141 /* 3141 /*
3142 * atomic_inc/dec() is required to ha 3142 * atomic_inc/dec() is required to handle the horrid abuse of this
3143 * function by the reboot and kexec c 3143 * function by the reboot and kexec code which invoke it from
3144 * IPI/NMI broadcasts when shutting d 3144 * IPI/NMI broadcasts when shutting down CPUs. Invocation from
3145 * regular CPU hotplug is properly se 3145 * regular CPU hotplug is properly serialized.
3146 * 3146 *
3147 * Note, that the fact that __num_onl 3147 * Note, that the fact that __num_online_cpus is of type atomic_t
3148 * does not protect readers which are 3148 * does not protect readers which are not serialized against
3149 * concurrent hotplug operations. 3149 * concurrent hotplug operations.
3150 */ 3150 */
3151 if (online) { 3151 if (online) {
3152 if (!cpumask_test_and_set_cpu 3152 if (!cpumask_test_and_set_cpu(cpu, &__cpu_online_mask))
3153 atomic_inc(&__num_onl 3153 atomic_inc(&__num_online_cpus);
3154 } else { 3154 } else {
3155 if (cpumask_test_and_clear_cp 3155 if (cpumask_test_and_clear_cpu(cpu, &__cpu_online_mask))
3156 atomic_dec(&__num_onl 3156 atomic_dec(&__num_online_cpus);
3157 } 3157 }
3158 } 3158 }
3159 3159
3160 /* 3160 /*
3161 * Activate the first processor. 3161 * Activate the first processor.
3162 */ 3162 */
3163 void __init boot_cpu_init(void) 3163 void __init boot_cpu_init(void)
3164 { 3164 {
3165 int cpu = smp_processor_id(); 3165 int cpu = smp_processor_id();
3166 3166
3167 /* Mark the boot cpu "present", "onli 3167 /* Mark the boot cpu "present", "online" etc for SMP and UP case */
3168 set_cpu_online(cpu, true); 3168 set_cpu_online(cpu, true);
3169 set_cpu_active(cpu, true); 3169 set_cpu_active(cpu, true);
3170 set_cpu_present(cpu, true); 3170 set_cpu_present(cpu, true);
3171 set_cpu_possible(cpu, true); 3171 set_cpu_possible(cpu, true);
3172 3172
3173 #ifdef CONFIG_SMP 3173 #ifdef CONFIG_SMP
3174 __boot_cpu_id = cpu; 3174 __boot_cpu_id = cpu;
3175 #endif 3175 #endif
3176 } 3176 }
3177 3177
3178 /* 3178 /*
3179 * Must be called _AFTER_ setting up the per_ 3179 * Must be called _AFTER_ setting up the per_cpu areas
3180 */ 3180 */
3181 void __init boot_cpu_hotplug_init(void) 3181 void __init boot_cpu_hotplug_init(void)
3182 { 3182 {
3183 #ifdef CONFIG_SMP 3183 #ifdef CONFIG_SMP
3184 cpumask_set_cpu(smp_processor_id(), & 3184 cpumask_set_cpu(smp_processor_id(), &cpus_booted_once_mask);
3185 atomic_set(this_cpu_ptr(&cpuhp_state. 3185 atomic_set(this_cpu_ptr(&cpuhp_state.ap_sync_state), SYNC_STATE_ONLINE);
3186 #endif 3186 #endif
3187 this_cpu_write(cpuhp_state.state, CPU 3187 this_cpu_write(cpuhp_state.state, CPUHP_ONLINE);
3188 this_cpu_write(cpuhp_state.target, CP 3188 this_cpu_write(cpuhp_state.target, CPUHP_ONLINE);
3189 } 3189 }
3190 3190
3191 #ifdef CONFIG_CPU_MITIGATIONS 3191 #ifdef CONFIG_CPU_MITIGATIONS
3192 /* 3192 /*
3193 * These are used for a global "mitigations=" 3193 * These are used for a global "mitigations=" cmdline option for toggling
3194 * optional CPU mitigations. 3194 * optional CPU mitigations.
3195 */ 3195 */
3196 enum cpu_mitigations { 3196 enum cpu_mitigations {
3197 CPU_MITIGATIONS_OFF, 3197 CPU_MITIGATIONS_OFF,
3198 CPU_MITIGATIONS_AUTO, 3198 CPU_MITIGATIONS_AUTO,
3199 CPU_MITIGATIONS_AUTO_NOSMT, 3199 CPU_MITIGATIONS_AUTO_NOSMT,
3200 }; 3200 };
3201 3201
3202 static enum cpu_mitigations cpu_mitigations _ 3202 static enum cpu_mitigations cpu_mitigations __ro_after_init = CPU_MITIGATIONS_AUTO;
3203 3203
3204 static int __init mitigations_parse_cmdline(c 3204 static int __init mitigations_parse_cmdline(char *arg)
3205 { 3205 {
3206 if (!strcmp(arg, "off")) 3206 if (!strcmp(arg, "off"))
3207 cpu_mitigations = CPU_MITIGAT 3207 cpu_mitigations = CPU_MITIGATIONS_OFF;
3208 else if (!strcmp(arg, "auto")) 3208 else if (!strcmp(arg, "auto"))
3209 cpu_mitigations = CPU_MITIGAT 3209 cpu_mitigations = CPU_MITIGATIONS_AUTO;
3210 else if (!strcmp(arg, "auto,nosmt")) 3210 else if (!strcmp(arg, "auto,nosmt"))
3211 cpu_mitigations = CPU_MITIGAT 3211 cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT;
3212 else 3212 else
3213 pr_crit("Unsupported mitigati 3213 pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
3214 arg); 3214 arg);
3215 3215
3216 return 0; 3216 return 0;
3217 } 3217 }
3218 3218
3219 /* mitigations=off */ 3219 /* mitigations=off */
3220 bool cpu_mitigations_off(void) 3220 bool cpu_mitigations_off(void)
3221 { 3221 {
3222 return cpu_mitigations == CPU_MITIGAT 3222 return cpu_mitigations == CPU_MITIGATIONS_OFF;
3223 } 3223 }
3224 EXPORT_SYMBOL_GPL(cpu_mitigations_off); 3224 EXPORT_SYMBOL_GPL(cpu_mitigations_off);
3225 3225
3226 /* mitigations=auto,nosmt */ 3226 /* mitigations=auto,nosmt */
3227 bool cpu_mitigations_auto_nosmt(void) 3227 bool cpu_mitigations_auto_nosmt(void)
3228 { 3228 {
3229 return cpu_mitigations == CPU_MITIGAT 3229 return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT;
3230 } 3230 }
3231 EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt) 3231 EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt);
3232 #else 3232 #else
3233 static int __init mitigations_parse_cmdline(c 3233 static int __init mitigations_parse_cmdline(char *arg)
3234 { 3234 {
3235 pr_crit("Kernel compiled without miti 3235 pr_crit("Kernel compiled without mitigations, ignoring 'mitigations'; system may still be vulnerable\n");
3236 return 0; 3236 return 0;
3237 } 3237 }
3238 #endif 3238 #endif
3239 early_param("mitigations", mitigations_parse_ 3239 early_param("mitigations", mitigations_parse_cmdline);
3240 3240
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