1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * pseries CPU Hotplug infrastructure.
4 *
5 * Split out from arch/powerpc/platforms/pseries/setup.c
6 * arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c
7 *
8 * Peter Bergner, IBM March 2001.
9 * Copyright (C) 2001 IBM.
10 * Dave Engebretsen, Peter Bergner, and
11 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
12 * Plus various changes from other IBM teams...
13 *
14 * Copyright (C) 2006 Michael Ellerman, IBM Corporation
15 */
16
17 #define pr_fmt(fmt) "pseries-hotplug-cpu: " fmt
18
19 #include <linux/kernel.h>
20 #include <linux/interrupt.h>
21 #include <linux/delay.h>
22 #include <linux/sched.h> /* for idle_task_exit */
23 #include <linux/sched/hotplug.h>
24 #include <linux/cpu.h>
25 #include <linux/of.h>
26 #include <linux/slab.h>
27 #include <asm/prom.h>
28 #include <asm/rtas.h>
29 #include <asm/firmware.h>
30 #include <asm/machdep.h>
31 #include <asm/vdso_datapage.h>
32 #include <asm/xics.h>
33 #include <asm/xive.h>
34 #include <asm/plpar_wrappers.h>
35 #include <asm/topology.h>
36
37 #include "pseries.h"
38 #include "offline_states.h"
39
40 /* This version can't take the spinlock, because it never returns */
41 static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
42
43 static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) =
44 CPU_STATE_OFFLINE;
45 static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE;
46
47 static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE;
48
49 static bool cede_offline_enabled __read_mostly = true;
50
51 /*
52 * Enable/disable cede_offline when available.
53 */
setup_cede_offline(char * str)54 static int __init setup_cede_offline(char *str)
55 {
56 return (kstrtobool(str, &cede_offline_enabled) == 0);
57 }
58
59 __setup("cede_offline=", setup_cede_offline);
60
get_cpu_current_state(int cpu)61 enum cpu_state_vals get_cpu_current_state(int cpu)
62 {
63 return per_cpu(current_state, cpu);
64 }
65
set_cpu_current_state(int cpu,enum cpu_state_vals state)66 void set_cpu_current_state(int cpu, enum cpu_state_vals state)
67 {
68 per_cpu(current_state, cpu) = state;
69 }
70
get_preferred_offline_state(int cpu)71 enum cpu_state_vals get_preferred_offline_state(int cpu)
72 {
73 return per_cpu(preferred_offline_state, cpu);
74 }
75
set_preferred_offline_state(int cpu,enum cpu_state_vals state)76 void set_preferred_offline_state(int cpu, enum cpu_state_vals state)
77 {
78 per_cpu(preferred_offline_state, cpu) = state;
79 }
80
set_default_offline_state(int cpu)81 void set_default_offline_state(int cpu)
82 {
83 per_cpu(preferred_offline_state, cpu) = default_offline_state;
84 }
85
rtas_stop_self(void)86 static void rtas_stop_self(void)
87 {
88 static struct rtas_args args;
89
90 local_irq_disable();
91
92 BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
93
94 printk("cpu %u (hwid %u) Ready to die...\n",
95 smp_processor_id(), hard_smp_processor_id());
96
97 rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
98
99 panic("Alas, I survived.\n");
100 }
101
pseries_mach_cpu_die(void)102 static void pseries_mach_cpu_die(void)
103 {
104 unsigned int cpu = smp_processor_id();
105 unsigned int hwcpu = hard_smp_processor_id();
106 u8 cede_latency_hint = 0;
107
108 local_irq_disable();
109 idle_task_exit();
110 if (xive_enabled())
111 xive_teardown_cpu();
112 else
113 xics_teardown_cpu();
114
115 if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
116 set_cpu_current_state(cpu, CPU_STATE_INACTIVE);
117 if (ppc_md.suspend_disable_cpu)
118 ppc_md.suspend_disable_cpu();
119
120 cede_latency_hint = 2;
121
122 get_lppaca()->idle = 1;
123 if (!lppaca_shared_proc(get_lppaca()))
124 get_lppaca()->donate_dedicated_cpu = 1;
125
126 while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
127 while (!prep_irq_for_idle()) {
128 local_irq_enable();
129 local_irq_disable();
130 }
131
132 extended_cede_processor(cede_latency_hint);
133 }
134
135 local_irq_disable();
136
137 if (!lppaca_shared_proc(get_lppaca()))
138 get_lppaca()->donate_dedicated_cpu = 0;
139 get_lppaca()->idle = 0;
140
141 if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
142 unregister_slb_shadow(hwcpu);
143
144 hard_irq_disable();
145 /*
146 * Call to start_secondary_resume() will not return.
147 * Kernel stack will be reset and start_secondary()
148 * will be called to continue the online operation.
149 */
150 start_secondary_resume();
151 }
152 }
153
154 /* Requested state is CPU_STATE_OFFLINE at this point */
155 WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE);
156
157 set_cpu_current_state(cpu, CPU_STATE_OFFLINE);
158 unregister_slb_shadow(hwcpu);
159 rtas_stop_self();
160
161 /* Should never get here... */
162 BUG();
163 for(;;);
164 }
165
pseries_cpu_disable(void)166 static int pseries_cpu_disable(void)
167 {
168 int cpu = smp_processor_id();
169
170 set_cpu_online(cpu, false);
171 vdso_data->processorCount--;
172
173 /*fix boot_cpuid here*/
174 if (cpu == boot_cpuid)
175 boot_cpuid = cpumask_any(cpu_online_mask);
176
177 /* FIXME: abstract this to not be platform specific later on */
178 if (xive_enabled())
179 xive_smp_disable_cpu();
180 else
181 xics_migrate_irqs_away();
182 return 0;
183 }
184
185 /*
186 * pseries_cpu_die: Wait for the cpu to die.
187 * @cpu: logical processor id of the CPU whose death we're awaiting.
188 *
189 * This function is called from the context of the thread which is performing
190 * the cpu-offline. Here we wait for long enough to allow the cpu in question
191 * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
192 * notifications.
193 *
194 * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to
195 * self-destruct.
196 */
pseries_cpu_die(unsigned int cpu)197 static void pseries_cpu_die(unsigned int cpu)
198 {
199 int tries;
200 int cpu_status = 1;
201 unsigned int pcpu = get_hard_smp_processor_id(cpu);
202
203 if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
204 cpu_status = 1;
205 for (tries = 0; tries < 5000; tries++) {
206 if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) {
207 cpu_status = 0;
208 break;
209 }
210 msleep(1);
211 }
212 } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {
213
214 for (tries = 0; tries < 25; tries++) {
215 cpu_status = smp_query_cpu_stopped(pcpu);
216 if (cpu_status == QCSS_STOPPED ||
217 cpu_status == QCSS_HARDWARE_ERROR)
218 break;
219 cpu_relax();
220 }
221 }
222
223 if (cpu_status != 0) {
224 printk("Querying DEAD? cpu %i (%i) shows %i\n",
225 cpu, pcpu, cpu_status);
226 }
227
228 /* Isolation and deallocation are definitely done by
229 * drslot_chrp_cpu. If they were not they would be
230 * done here. Change isolate state to Isolate and
231 * change allocation-state to Unusable.
232 */
233 paca_ptrs[cpu]->cpu_start = 0;
234 }
235
236 /*
237 * Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle
238 * here is that a cpu device node may represent up to two logical cpus
239 * in the SMT case. We must honor the assumption in other code that
240 * the logical ids for sibling SMT threads x and y are adjacent, such
241 * that x^1 == y and y^1 == x.
242 */
pseries_add_processor(struct device_node * np)243 static int pseries_add_processor(struct device_node *np)
244 {
245 unsigned int cpu;
246 cpumask_var_t candidate_mask, tmp;
247 int err = -ENOSPC, len, nthreads, i;
248 const __be32 *intserv;
249
250 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
251 if (!intserv)
252 return 0;
253
254 zalloc_cpumask_var(&candidate_mask, GFP_KERNEL);
255 zalloc_cpumask_var(&tmp, GFP_KERNEL);
256
257 nthreads = len / sizeof(u32);
258 for (i = 0; i < nthreads; i++)
259 cpumask_set_cpu(i, tmp);
260
261 cpu_maps_update_begin();
262
263 BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask));
264
265 /* Get a bitmap of unoccupied slots. */
266 cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask);
267 if (cpumask_empty(candidate_mask)) {
268 /* If we get here, it most likely means that NR_CPUS is
269 * less than the partition's max processors setting.
270 */
271 printk(KERN_ERR "Cannot add cpu %pOF; this system configuration"
272 " supports %d logical cpus.\n", np,
273 num_possible_cpus());
274 goto out_unlock;
275 }
276
277 while (!cpumask_empty(tmp))
278 if (cpumask_subset(tmp, candidate_mask))
279 /* Found a range where we can insert the new cpu(s) */
280 break;
281 else
282 cpumask_shift_left(tmp, tmp, nthreads);
283
284 if (cpumask_empty(tmp)) {
285 printk(KERN_ERR "Unable to find space in cpu_present_mask for"
286 " processor %pOFn with %d thread(s)\n", np,
287 nthreads);
288 goto out_unlock;
289 }
290
291 for_each_cpu(cpu, tmp) {
292 BUG_ON(cpu_present(cpu));
293 set_cpu_present(cpu, true);
294 set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv++));
295 }
296 err = 0;
297 out_unlock:
298 cpu_maps_update_done();
299 free_cpumask_var(candidate_mask);
300 free_cpumask_var(tmp);
301 return err;
302 }
303
304 /*
305 * Update the present map for a cpu node which is going away, and set
306 * the hard id in the paca(s) to -1 to be consistent with boot time
307 * convention for non-present cpus.
308 */
pseries_remove_processor(struct device_node * np)309 static void pseries_remove_processor(struct device_node *np)
310 {
311 unsigned int cpu;
312 int len, nthreads, i;
313 const __be32 *intserv;
314 u32 thread;
315
316 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
317 if (!intserv)
318 return;
319
320 nthreads = len / sizeof(u32);
321
322 cpu_maps_update_begin();
323 for (i = 0; i < nthreads; i++) {
324 thread = be32_to_cpu(intserv[i]);
325 for_each_present_cpu(cpu) {
326 if (get_hard_smp_processor_id(cpu) != thread)
327 continue;
328 BUG_ON(cpu_online(cpu));
329 set_cpu_present(cpu, false);
330 set_hard_smp_processor_id(cpu, -1);
331 update_numa_cpu_lookup_table(cpu, -1);
332 break;
333 }
334 if (cpu >= nr_cpu_ids)
335 printk(KERN_WARNING "Could not find cpu to remove "
336 "with physical id 0x%x\n", thread);
337 }
338 cpu_maps_update_done();
339 }
340
dlpar_online_cpu(struct device_node * dn)341 static int dlpar_online_cpu(struct device_node *dn)
342 {
343 int rc = 0;
344 unsigned int cpu;
345 int len, nthreads, i;
346 const __be32 *intserv;
347 u32 thread;
348
349 intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
350 if (!intserv)
351 return -EINVAL;
352
353 nthreads = len / sizeof(u32);
354
355 cpu_maps_update_begin();
356 for (i = 0; i < nthreads; i++) {
357 thread = be32_to_cpu(intserv[i]);
358 for_each_present_cpu(cpu) {
359 if (get_hard_smp_processor_id(cpu) != thread)
360 continue;
361 BUG_ON(get_cpu_current_state(cpu)
362 != CPU_STATE_OFFLINE);
363 cpu_maps_update_done();
364 timed_topology_update(1);
365 find_and_online_cpu_nid(cpu);
366 rc = device_online(get_cpu_device(cpu));
367 if (rc)
368 goto out;
369 cpu_maps_update_begin();
370
371 break;
372 }
373 if (cpu == num_possible_cpus())
374 printk(KERN_WARNING "Could not find cpu to online "
375 "with physical id 0x%x\n", thread);
376 }
377 cpu_maps_update_done();
378
379 out:
380 return rc;
381
382 }
383
dlpar_cpu_exists(struct device_node * parent,u32 drc_index)384 static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index)
385 {
386 struct device_node *child = NULL;
387 u32 my_drc_index;
388 bool found;
389 int rc;
390
391 /* Assume cpu doesn't exist */
392 found = false;
393
394 for_each_child_of_node(parent, child) {
395 rc = of_property_read_u32(child, "ibm,my-drc-index",
396 &my_drc_index);
397 if (rc)
398 continue;
399
400 if (my_drc_index == drc_index) {
401 of_node_put(child);
402 found = true;
403 break;
404 }
405 }
406
407 return found;
408 }
409
valid_cpu_drc_index(struct device_node * parent,u32 drc_index)410 static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
411 {
412 bool found = false;
413 int rc, index;
414
415 index = 0;
416 while (!found) {
417 u32 drc;
418
419 rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
420 index++, &drc);
421 if (rc)
422 break;
423
424 if (drc == drc_index)
425 found = true;
426 }
427
428 return found;
429 }
430
dlpar_cpu_add(u32 drc_index)431 static ssize_t dlpar_cpu_add(u32 drc_index)
432 {
433 struct device_node *dn, *parent;
434 int rc, saved_rc;
435
436 pr_debug("Attempting to add CPU, drc index: %x\n", drc_index);
437
438 parent = of_find_node_by_path("/cpus");
439 if (!parent) {
440 pr_warn("Failed to find CPU root node \"/cpus\"\n");
441 return -ENODEV;
442 }
443
444 if (dlpar_cpu_exists(parent, drc_index)) {
445 of_node_put(parent);
446 pr_warn("CPU with drc index %x already exists\n", drc_index);
447 return -EINVAL;
448 }
449
450 if (!valid_cpu_drc_index(parent, drc_index)) {
451 of_node_put(parent);
452 pr_warn("Cannot find CPU (drc index %x) to add.\n", drc_index);
453 return -EINVAL;
454 }
455
456 rc = dlpar_acquire_drc(drc_index);
457 if (rc) {
458 pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
459 rc, drc_index);
460 of_node_put(parent);
461 return -EINVAL;
462 }
463
464 dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
465 if (!dn) {
466 pr_warn("Failed call to configure-connector, drc index: %x\n",
467 drc_index);
468 dlpar_release_drc(drc_index);
469 of_node_put(parent);
470 return -EINVAL;
471 }
472
473 rc = dlpar_attach_node(dn, parent);
474
475 /* Regardless we are done with parent now */
476 of_node_put(parent);
477
478 if (rc) {
479 saved_rc = rc;
480 pr_warn("Failed to attach node %pOFn, rc: %d, drc index: %x\n",
481 dn, rc, drc_index);
482
483 rc = dlpar_release_drc(drc_index);
484 if (!rc)
485 dlpar_free_cc_nodes(dn);
486
487 return saved_rc;
488 }
489
490 rc = dlpar_online_cpu(dn);
491 if (rc) {
492 saved_rc = rc;
493 pr_warn("Failed to online cpu %pOFn, rc: %d, drc index: %x\n",
494 dn, rc, drc_index);
495
496 rc = dlpar_detach_node(dn);
497 if (!rc)
498 dlpar_release_drc(drc_index);
499
500 return saved_rc;
501 }
502
503 pr_debug("Successfully added CPU %pOFn, drc index: %x\n", dn,
504 drc_index);
505 return rc;
506 }
507
dlpar_offline_cpu(struct device_node * dn)508 static int dlpar_offline_cpu(struct device_node *dn)
509 {
510 int rc = 0;
511 unsigned int cpu;
512 int len, nthreads, i;
513 const __be32 *intserv;
514 u32 thread;
515
516 intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
517 if (!intserv)
518 return -EINVAL;
519
520 nthreads = len / sizeof(u32);
521
522 cpu_maps_update_begin();
523 for (i = 0; i < nthreads; i++) {
524 thread = be32_to_cpu(intserv[i]);
525 for_each_present_cpu(cpu) {
526 if (get_hard_smp_processor_id(cpu) != thread)
527 continue;
528
529 if (get_cpu_current_state(cpu) == CPU_STATE_OFFLINE)
530 break;
531
532 if (get_cpu_current_state(cpu) == CPU_STATE_ONLINE) {
533 set_preferred_offline_state(cpu,
534 CPU_STATE_OFFLINE);
535 cpu_maps_update_done();
536 timed_topology_update(1);
537 rc = device_offline(get_cpu_device(cpu));
538 if (rc)
539 goto out;
540 cpu_maps_update_begin();
541 break;
542
543 }
544
545 /*
546 * The cpu is in CPU_STATE_INACTIVE.
547 * Upgrade it's state to CPU_STATE_OFFLINE.
548 */
549 set_preferred_offline_state(cpu, CPU_STATE_OFFLINE);
550 BUG_ON(plpar_hcall_norets(H_PROD, thread)
551 != H_SUCCESS);
552 __cpu_die(cpu);
553 break;
554 }
555 if (cpu == num_possible_cpus())
556 printk(KERN_WARNING "Could not find cpu to offline with physical id 0x%x\n", thread);
557 }
558 cpu_maps_update_done();
559
560 out:
561 return rc;
562
563 }
564
dlpar_cpu_remove(struct device_node * dn,u32 drc_index)565 static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
566 {
567 int rc;
568
569 pr_debug("Attempting to remove CPU %pOFn, drc index: %x\n",
570 dn, drc_index);
571
572 rc = dlpar_offline_cpu(dn);
573 if (rc) {
574 pr_warn("Failed to offline CPU %pOFn, rc: %d\n", dn, rc);
575 return -EINVAL;
576 }
577
578 rc = dlpar_release_drc(drc_index);
579 if (rc) {
580 pr_warn("Failed to release drc (%x) for CPU %pOFn, rc: %d\n",
581 drc_index, dn, rc);
582 dlpar_online_cpu(dn);
583 return rc;
584 }
585
586 rc = dlpar_detach_node(dn);
587 if (rc) {
588 int saved_rc = rc;
589
590 pr_warn("Failed to detach CPU %pOFn, rc: %d", dn, rc);
591
592 rc = dlpar_acquire_drc(drc_index);
593 if (!rc)
594 dlpar_online_cpu(dn);
595
596 return saved_rc;
597 }
598
599 pr_debug("Successfully removed CPU, drc index: %x\n", drc_index);
600 return 0;
601 }
602
cpu_drc_index_to_dn(u32 drc_index)603 static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
604 {
605 struct device_node *dn;
606 u32 my_index;
607 int rc;
608
609 for_each_node_by_type(dn, "cpu") {
610 rc = of_property_read_u32(dn, "ibm,my-drc-index", &my_index);
611 if (rc)
612 continue;
613
614 if (my_index == drc_index)
615 break;
616 }
617
618 return dn;
619 }
620
dlpar_cpu_remove_by_index(u32 drc_index)621 static int dlpar_cpu_remove_by_index(u32 drc_index)
622 {
623 struct device_node *dn;
624 int rc;
625
626 dn = cpu_drc_index_to_dn(drc_index);
627 if (!dn) {
628 pr_warn("Cannot find CPU (drc index %x) to remove\n",
629 drc_index);
630 return -ENODEV;
631 }
632
633 rc = dlpar_cpu_remove(dn, drc_index);
634 of_node_put(dn);
635 return rc;
636 }
637
find_dlpar_cpus_to_remove(u32 * cpu_drcs,int cpus_to_remove)638 static int find_dlpar_cpus_to_remove(u32 *cpu_drcs, int cpus_to_remove)
639 {
640 struct device_node *dn;
641 int cpus_found = 0;
642 int rc;
643
644 /* We want to find cpus_to_remove + 1 CPUs to ensure we do not
645 * remove the last CPU.
646 */
647 for_each_node_by_type(dn, "cpu") {
648 cpus_found++;
649
650 if (cpus_found > cpus_to_remove) {
651 of_node_put(dn);
652 break;
653 }
654
655 /* Note that cpus_found is always 1 ahead of the index
656 * into the cpu_drcs array, so we use cpus_found - 1
657 */
658 rc = of_property_read_u32(dn, "ibm,my-drc-index",
659 &cpu_drcs[cpus_found - 1]);
660 if (rc) {
661 pr_warn("Error occurred getting drc-index for %pOFn\n",
662 dn);
663 of_node_put(dn);
664 return -1;
665 }
666 }
667
668 if (cpus_found < cpus_to_remove) {
669 pr_warn("Failed to find enough CPUs (%d of %d) to remove\n",
670 cpus_found, cpus_to_remove);
671 } else if (cpus_found == cpus_to_remove) {
672 pr_warn("Cannot remove all CPUs\n");
673 }
674
675 return cpus_found;
676 }
677
dlpar_cpu_remove_by_count(u32 cpus_to_remove)678 static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
679 {
680 u32 *cpu_drcs;
681 int cpus_found;
682 int cpus_removed = 0;
683 int i, rc;
684
685 pr_debug("Attempting to hot-remove %d CPUs\n", cpus_to_remove);
686
687 cpu_drcs = kcalloc(cpus_to_remove, sizeof(*cpu_drcs), GFP_KERNEL);
688 if (!cpu_drcs)
689 return -EINVAL;
690
691 cpus_found = find_dlpar_cpus_to_remove(cpu_drcs, cpus_to_remove);
692 if (cpus_found <= cpus_to_remove) {
693 kfree(cpu_drcs);
694 return -EINVAL;
695 }
696
697 for (i = 0; i < cpus_to_remove; i++) {
698 rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
699 if (rc)
700 break;
701
702 cpus_removed++;
703 }
704
705 if (cpus_removed != cpus_to_remove) {
706 pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
707
708 for (i = 0; i < cpus_removed; i++)
709 dlpar_cpu_add(cpu_drcs[i]);
710
711 rc = -EINVAL;
712 } else {
713 rc = 0;
714 }
715
716 kfree(cpu_drcs);
717 return rc;
718 }
719
find_dlpar_cpus_to_add(u32 * cpu_drcs,u32 cpus_to_add)720 static int find_dlpar_cpus_to_add(u32 *cpu_drcs, u32 cpus_to_add)
721 {
722 struct device_node *parent;
723 int cpus_found = 0;
724 int index, rc;
725
726 parent = of_find_node_by_path("/cpus");
727 if (!parent) {
728 pr_warn("Could not find CPU root node in device tree\n");
729 kfree(cpu_drcs);
730 return -1;
731 }
732
733 /* Search the ibm,drc-indexes array for possible CPU drcs to
734 * add. Note that the format of the ibm,drc-indexes array is
735 * the number of entries in the array followed by the array
736 * of drc values so we start looking at index = 1.
737 */
738 index = 1;
739 while (cpus_found < cpus_to_add) {
740 u32 drc;
741
742 rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
743 index++, &drc);
744 if (rc)
745 break;
746
747 if (dlpar_cpu_exists(parent, drc))
748 continue;
749
750 cpu_drcs[cpus_found++] = drc;
751 }
752
753 of_node_put(parent);
754 return cpus_found;
755 }
756
dlpar_cpu_add_by_count(u32 cpus_to_add)757 static int dlpar_cpu_add_by_count(u32 cpus_to_add)
758 {
759 u32 *cpu_drcs;
760 int cpus_added = 0;
761 int cpus_found;
762 int i, rc;
763
764 pr_debug("Attempting to hot-add %d CPUs\n", cpus_to_add);
765
766 cpu_drcs = kcalloc(cpus_to_add, sizeof(*cpu_drcs), GFP_KERNEL);
767 if (!cpu_drcs)
768 return -EINVAL;
769
770 cpus_found = find_dlpar_cpus_to_add(cpu_drcs, cpus_to_add);
771 if (cpus_found < cpus_to_add) {
772 pr_warn("Failed to find enough CPUs (%d of %d) to add\n",
773 cpus_found, cpus_to_add);
774 kfree(cpu_drcs);
775 return -EINVAL;
776 }
777
778 for (i = 0; i < cpus_to_add; i++) {
779 rc = dlpar_cpu_add(cpu_drcs[i]);
780 if (rc)
781 break;
782
783 cpus_added++;
784 }
785
786 if (cpus_added < cpus_to_add) {
787 pr_warn("CPU hot-add failed, removing any added CPUs\n");
788
789 for (i = 0; i < cpus_added; i++)
790 dlpar_cpu_remove_by_index(cpu_drcs[i]);
791
792 rc = -EINVAL;
793 } else {
794 rc = 0;
795 }
796
797 kfree(cpu_drcs);
798 return rc;
799 }
800
dlpar_cpu_readd(int cpu)801 int dlpar_cpu_readd(int cpu)
802 {
803 struct device_node *dn;
804 struct device *dev;
805 u32 drc_index;
806 int rc;
807
808 dev = get_cpu_device(cpu);
809 dn = dev->of_node;
810
811 rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
812
813 rc = dlpar_cpu_remove_by_index(drc_index);
814 if (!rc)
815 rc = dlpar_cpu_add(drc_index);
816
817 return rc;
818 }
819
dlpar_cpu(struct pseries_hp_errorlog * hp_elog)820 int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
821 {
822 u32 count, drc_index;
823 int rc;
824
825 count = hp_elog->_drc_u.drc_count;
826 drc_index = hp_elog->_drc_u.drc_index;
827
828 lock_device_hotplug();
829
830 switch (hp_elog->action) {
831 case PSERIES_HP_ELOG_ACTION_REMOVE:
832 if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
833 rc = dlpar_cpu_remove_by_count(count);
834 else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
835 rc = dlpar_cpu_remove_by_index(drc_index);
836 else
837 rc = -EINVAL;
838 break;
839 case PSERIES_HP_ELOG_ACTION_ADD:
840 if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
841 rc = dlpar_cpu_add_by_count(count);
842 else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
843 rc = dlpar_cpu_add(drc_index);
844 else
845 rc = -EINVAL;
846 break;
847 default:
848 pr_err("Invalid action (%d) specified\n", hp_elog->action);
849 rc = -EINVAL;
850 break;
851 }
852
853 unlock_device_hotplug();
854 return rc;
855 }
856
857 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
858
dlpar_cpu_probe(const char * buf,size_t count)859 static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
860 {
861 u32 drc_index;
862 int rc;
863
864 rc = kstrtou32(buf, 0, &drc_index);
865 if (rc)
866 return -EINVAL;
867
868 rc = dlpar_cpu_add(drc_index);
869
870 return rc ? rc : count;
871 }
872
dlpar_cpu_release(const char * buf,size_t count)873 static ssize_t dlpar_cpu_release(const char *buf, size_t count)
874 {
875 struct device_node *dn;
876 u32 drc_index;
877 int rc;
878
879 dn = of_find_node_by_path(buf);
880 if (!dn)
881 return -EINVAL;
882
883 rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
884 if (rc) {
885 of_node_put(dn);
886 return -EINVAL;
887 }
888
889 rc = dlpar_cpu_remove(dn, drc_index);
890 of_node_put(dn);
891
892 return rc ? rc : count;
893 }
894
895 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
896
pseries_smp_notifier(struct notifier_block * nb,unsigned long action,void * data)897 static int pseries_smp_notifier(struct notifier_block *nb,
898 unsigned long action, void *data)
899 {
900 struct of_reconfig_data *rd = data;
901 int err = 0;
902
903 switch (action) {
904 case OF_RECONFIG_ATTACH_NODE:
905 err = pseries_add_processor(rd->dn);
906 break;
907 case OF_RECONFIG_DETACH_NODE:
908 pseries_remove_processor(rd->dn);
909 break;
910 }
911 return notifier_from_errno(err);
912 }
913
914 static struct notifier_block pseries_smp_nb = {
915 .notifier_call = pseries_smp_notifier,
916 };
917
918 #define MAX_CEDE_LATENCY_LEVELS 4
919 #define CEDE_LATENCY_PARAM_LENGTH 10
920 #define CEDE_LATENCY_PARAM_MAX_LENGTH \
921 (MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char))
922 #define CEDE_LATENCY_TOKEN 45
923
924 static char cede_parameters[CEDE_LATENCY_PARAM_MAX_LENGTH];
925
parse_cede_parameters(void)926 static int parse_cede_parameters(void)
927 {
928 memset(cede_parameters, 0, CEDE_LATENCY_PARAM_MAX_LENGTH);
929 return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
930 NULL,
931 CEDE_LATENCY_TOKEN,
932 __pa(cede_parameters),
933 CEDE_LATENCY_PARAM_MAX_LENGTH);
934 }
935
pseries_cpu_hotplug_init(void)936 static int __init pseries_cpu_hotplug_init(void)
937 {
938 int cpu;
939 int qcss_tok;
940
941 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
942 ppc_md.cpu_probe = dlpar_cpu_probe;
943 ppc_md.cpu_release = dlpar_cpu_release;
944 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
945
946 rtas_stop_self_token = rtas_token("stop-self");
947 qcss_tok = rtas_token("query-cpu-stopped-state");
948
949 if (rtas_stop_self_token == RTAS_UNKNOWN_SERVICE ||
950 qcss_tok == RTAS_UNKNOWN_SERVICE) {
951 printk(KERN_INFO "CPU Hotplug not supported by firmware "
952 "- disabling.\n");
953 return 0;
954 }
955
956 ppc_md.cpu_die = pseries_mach_cpu_die;
957 smp_ops->cpu_disable = pseries_cpu_disable;
958 smp_ops->cpu_die = pseries_cpu_die;
959
960 /* Processors can be added/removed only on LPAR */
961 if (firmware_has_feature(FW_FEATURE_LPAR)) {
962 of_reconfig_notifier_register(&pseries_smp_nb);
963 cpu_maps_update_begin();
964 if (cede_offline_enabled && parse_cede_parameters() == 0) {
965 default_offline_state = CPU_STATE_INACTIVE;
966 for_each_online_cpu(cpu)
967 set_default_offline_state(cpu);
968 }
969 cpu_maps_update_done();
970 }
971
972 return 0;
973 }
974 machine_arch_initcall(pseries, pseries_cpu_hotplug_init);
975