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
39 /* This version can't take the spinlock, because it never returns */
40 static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
41
rtas_stop_self(void)42 static void rtas_stop_self(void)
43 {
44 static struct rtas_args args;
45
46 local_irq_disable();
47
48 BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
49
50 rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
51
52 panic("Alas, I survived.\n");
53 }
54
pseries_cpu_offline_self(void)55 static void pseries_cpu_offline_self(void)
56 {
57 unsigned int hwcpu = hard_smp_processor_id();
58
59 local_irq_disable();
60 idle_task_exit();
61 if (xive_enabled())
62 xive_teardown_cpu();
63 else
64 xics_teardown_cpu();
65
66 unregister_slb_shadow(hwcpu);
67 rtas_stop_self();
68
69 /* Should never get here... */
70 BUG();
71 for(;;);
72 }
73
pseries_cpu_disable(void)74 static int pseries_cpu_disable(void)
75 {
76 int cpu = smp_processor_id();
77
78 set_cpu_online(cpu, false);
79 vdso_data->processorCount--;
80
81 /*fix boot_cpuid here*/
82 if (cpu == boot_cpuid)
83 boot_cpuid = cpumask_any(cpu_online_mask);
84
85 /* FIXME: abstract this to not be platform specific later on */
86 if (xive_enabled())
87 xive_smp_disable_cpu();
88 else
89 xics_migrate_irqs_away();
90
91 cleanup_cpu_mmu_context();
92
93 return 0;
94 }
95
96 /*
97 * pseries_cpu_die: Wait for the cpu to die.
98 * @cpu: logical processor id of the CPU whose death we're awaiting.
99 *
100 * This function is called from the context of the thread which is performing
101 * the cpu-offline. Here we wait for long enough to allow the cpu in question
102 * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
103 * notifications.
104 *
105 * OTOH, pseries_cpu_offline_self() is called by the @cpu when it wants to
106 * self-destruct.
107 */
pseries_cpu_die(unsigned int cpu)108 static void pseries_cpu_die(unsigned int cpu)
109 {
110 int cpu_status = 1;
111 unsigned int pcpu = get_hard_smp_processor_id(cpu);
112 unsigned long timeout = jiffies + msecs_to_jiffies(120000);
113
114 while (true) {
115 cpu_status = smp_query_cpu_stopped(pcpu);
116 if (cpu_status == QCSS_STOPPED ||
117 cpu_status == QCSS_HARDWARE_ERROR)
118 break;
119
120 if (time_after(jiffies, timeout)) {
121 pr_warn("CPU %i (hwid %i) didn't die after 120 seconds\n",
122 cpu, pcpu);
123 timeout = jiffies + msecs_to_jiffies(120000);
124 }
125
126 cond_resched();
127 }
128
129 if (cpu_status == QCSS_HARDWARE_ERROR) {
130 pr_warn("CPU %i (hwid %i) reported error while dying\n",
131 cpu, pcpu);
132 }
133
134 /* Isolation and deallocation are definitely done by
135 * drslot_chrp_cpu. If they were not they would be
136 * done here. Change isolate state to Isolate and
137 * change allocation-state to Unusable.
138 */
139 paca_ptrs[cpu]->cpu_start = 0;
140 }
141
142 /*
143 * Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle
144 * here is that a cpu device node may represent up to two logical cpus
145 * in the SMT case. We must honor the assumption in other code that
146 * the logical ids for sibling SMT threads x and y are adjacent, such
147 * that x^1 == y and y^1 == x.
148 */
pseries_add_processor(struct device_node * np)149 static int pseries_add_processor(struct device_node *np)
150 {
151 unsigned int cpu;
152 cpumask_var_t candidate_mask, tmp;
153 int err = -ENOSPC, len, nthreads, i;
154 const __be32 *intserv;
155
156 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
157 if (!intserv)
158 return 0;
159
160 zalloc_cpumask_var(&candidate_mask, GFP_KERNEL);
161 zalloc_cpumask_var(&tmp, GFP_KERNEL);
162
163 nthreads = len / sizeof(u32);
164 for (i = 0; i < nthreads; i++)
165 cpumask_set_cpu(i, tmp);
166
167 cpu_maps_update_begin();
168
169 BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask));
170
171 /* Get a bitmap of unoccupied slots. */
172 cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask);
173 if (cpumask_empty(candidate_mask)) {
174 /* If we get here, it most likely means that NR_CPUS is
175 * less than the partition's max processors setting.
176 */
177 printk(KERN_ERR "Cannot add cpu %pOF; this system configuration"
178 " supports %d logical cpus.\n", np,
179 num_possible_cpus());
180 goto out_unlock;
181 }
182
183 while (!cpumask_empty(tmp))
184 if (cpumask_subset(tmp, candidate_mask))
185 /* Found a range where we can insert the new cpu(s) */
186 break;
187 else
188 cpumask_shift_left(tmp, tmp, nthreads);
189
190 if (cpumask_empty(tmp)) {
191 printk(KERN_ERR "Unable to find space in cpu_present_mask for"
192 " processor %pOFn with %d thread(s)\n", np,
193 nthreads);
194 goto out_unlock;
195 }
196
197 for_each_cpu(cpu, tmp) {
198 BUG_ON(cpu_present(cpu));
199 set_cpu_present(cpu, true);
200 set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv++));
201 }
202 err = 0;
203 out_unlock:
204 cpu_maps_update_done();
205 free_cpumask_var(candidate_mask);
206 free_cpumask_var(tmp);
207 return err;
208 }
209
210 /*
211 * Update the present map for a cpu node which is going away, and set
212 * the hard id in the paca(s) to -1 to be consistent with boot time
213 * convention for non-present cpus.
214 */
pseries_remove_processor(struct device_node * np)215 static void pseries_remove_processor(struct device_node *np)
216 {
217 unsigned int cpu;
218 int len, nthreads, i;
219 const __be32 *intserv;
220 u32 thread;
221
222 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
223 if (!intserv)
224 return;
225
226 nthreads = len / sizeof(u32);
227
228 cpu_maps_update_begin();
229 for (i = 0; i < nthreads; i++) {
230 thread = be32_to_cpu(intserv[i]);
231 for_each_present_cpu(cpu) {
232 if (get_hard_smp_processor_id(cpu) != thread)
233 continue;
234 BUG_ON(cpu_online(cpu));
235 set_cpu_present(cpu, false);
236 set_hard_smp_processor_id(cpu, -1);
237 update_numa_cpu_lookup_table(cpu, -1);
238 break;
239 }
240 if (cpu >= nr_cpu_ids)
241 printk(KERN_WARNING "Could not find cpu to remove "
242 "with physical id 0x%x\n", thread);
243 }
244 cpu_maps_update_done();
245 }
246
dlpar_offline_cpu(struct device_node * dn)247 static int dlpar_offline_cpu(struct device_node *dn)
248 {
249 int rc = 0;
250 unsigned int cpu;
251 int len, nthreads, i;
252 const __be32 *intserv;
253 u32 thread;
254
255 intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
256 if (!intserv)
257 return -EINVAL;
258
259 nthreads = len / sizeof(u32);
260
261 cpu_maps_update_begin();
262 for (i = 0; i < nthreads; i++) {
263 thread = be32_to_cpu(intserv[i]);
264 for_each_present_cpu(cpu) {
265 if (get_hard_smp_processor_id(cpu) != thread)
266 continue;
267
268 if (!cpu_online(cpu))
269 break;
270
271 cpu_maps_update_done();
272 rc = device_offline(get_cpu_device(cpu));
273 if (rc)
274 goto out;
275 cpu_maps_update_begin();
276 break;
277 }
278 if (cpu == num_possible_cpus()) {
279 pr_warn("Could not find cpu to offline with physical id 0x%x\n",
280 thread);
281 }
282 }
283 cpu_maps_update_done();
284
285 out:
286 return rc;
287 }
288
dlpar_online_cpu(struct device_node * dn)289 static int dlpar_online_cpu(struct device_node *dn)
290 {
291 int rc = 0;
292 unsigned int cpu;
293 int len, nthreads, i;
294 const __be32 *intserv;
295 u32 thread;
296
297 intserv = of_get_property(dn, "ibm,ppc-interrupt-server#s", &len);
298 if (!intserv)
299 return -EINVAL;
300
301 nthreads = len / sizeof(u32);
302
303 cpu_maps_update_begin();
304 for (i = 0; i < nthreads; i++) {
305 thread = be32_to_cpu(intserv[i]);
306 for_each_present_cpu(cpu) {
307 if (get_hard_smp_processor_id(cpu) != thread)
308 continue;
309 cpu_maps_update_done();
310 find_and_online_cpu_nid(cpu);
311 rc = device_online(get_cpu_device(cpu));
312 if (rc) {
313 dlpar_offline_cpu(dn);
314 goto out;
315 }
316 cpu_maps_update_begin();
317
318 break;
319 }
320 if (cpu == num_possible_cpus())
321 printk(KERN_WARNING "Could not find cpu to online "
322 "with physical id 0x%x\n", thread);
323 }
324 cpu_maps_update_done();
325
326 out:
327 return rc;
328
329 }
330
dlpar_cpu_exists(struct device_node * parent,u32 drc_index)331 static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index)
332 {
333 struct device_node *child = NULL;
334 u32 my_drc_index;
335 bool found;
336 int rc;
337
338 /* Assume cpu doesn't exist */
339 found = false;
340
341 for_each_child_of_node(parent, child) {
342 rc = of_property_read_u32(child, "ibm,my-drc-index",
343 &my_drc_index);
344 if (rc)
345 continue;
346
347 if (my_drc_index == drc_index) {
348 of_node_put(child);
349 found = true;
350 break;
351 }
352 }
353
354 return found;
355 }
356
drc_info_valid_index(struct device_node * parent,u32 drc_index)357 static bool drc_info_valid_index(struct device_node *parent, u32 drc_index)
358 {
359 struct property *info;
360 struct of_drc_info drc;
361 const __be32 *value;
362 u32 index;
363 int count, i, j;
364
365 info = of_find_property(parent, "ibm,drc-info", NULL);
366 if (!info)
367 return false;
368
369 value = of_prop_next_u32(info, NULL, &count);
370
371 /* First value of ibm,drc-info is number of drc-info records */
372 if (value)
373 value++;
374 else
375 return false;
376
377 for (i = 0; i < count; i++) {
378 if (of_read_drc_info_cell(&info, &value, &drc))
379 return false;
380
381 if (strncmp(drc.drc_type, "CPU", 3))
382 break;
383
384 if (drc_index > drc.last_drc_index)
385 continue;
386
387 index = drc.drc_index_start;
388 for (j = 0; j < drc.num_sequential_elems; j++) {
389 if (drc_index == index)
390 return true;
391
392 index += drc.sequential_inc;
393 }
394 }
395
396 return false;
397 }
398
valid_cpu_drc_index(struct device_node * parent,u32 drc_index)399 static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
400 {
401 bool found = false;
402 int rc, index;
403
404 if (of_find_property(parent, "ibm,drc-info", NULL))
405 return drc_info_valid_index(parent, drc_index);
406
407 /* Note that the format of the ibm,drc-indexes array is
408 * the number of entries in the array followed by the array
409 * of drc values so we start looking at index = 1.
410 */
411 index = 1;
412 while (!found) {
413 u32 drc;
414
415 rc = of_property_read_u32_index(parent, "ibm,drc-indexes",
416 index++, &drc);
417
418 if (rc)
419 break;
420
421 if (drc == drc_index)
422 found = true;
423 }
424
425 return found;
426 }
427
dlpar_cpu_add(u32 drc_index)428 static ssize_t dlpar_cpu_add(u32 drc_index)
429 {
430 struct device_node *dn, *parent;
431 int rc, saved_rc;
432
433 pr_debug("Attempting to add CPU, drc index: %x\n", drc_index);
434
435 parent = of_find_node_by_path("/cpus");
436 if (!parent) {
437 pr_warn("Failed to find CPU root node \"/cpus\"\n");
438 return -ENODEV;
439 }
440
441 if (dlpar_cpu_exists(parent, drc_index)) {
442 of_node_put(parent);
443 pr_warn("CPU with drc index %x already exists\n", drc_index);
444 return -EINVAL;
445 }
446
447 if (!valid_cpu_drc_index(parent, drc_index)) {
448 of_node_put(parent);
449 pr_warn("Cannot find CPU (drc index %x) to add.\n", drc_index);
450 return -EINVAL;
451 }
452
453 rc = dlpar_acquire_drc(drc_index);
454 if (rc) {
455 pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
456 rc, drc_index);
457 of_node_put(parent);
458 return -EINVAL;
459 }
460
461 dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
462 if (!dn) {
463 pr_warn("Failed call to configure-connector, drc index: %x\n",
464 drc_index);
465 dlpar_release_drc(drc_index);
466 of_node_put(parent);
467 return -EINVAL;
468 }
469
470 rc = dlpar_attach_node(dn, parent);
471
472 /* Regardless we are done with parent now */
473 of_node_put(parent);
474
475 if (rc) {
476 saved_rc = rc;
477 pr_warn("Failed to attach node %pOFn, rc: %d, drc index: %x\n",
478 dn, rc, drc_index);
479
480 rc = dlpar_release_drc(drc_index);
481 if (!rc)
482 dlpar_free_cc_nodes(dn);
483
484 return saved_rc;
485 }
486
487 update_numa_distance(dn);
488
489 rc = dlpar_online_cpu(dn);
490 if (rc) {
491 saved_rc = rc;
492 pr_warn("Failed to online cpu %pOFn, rc: %d, drc index: %x\n",
493 dn, rc, drc_index);
494
495 rc = dlpar_detach_node(dn);
496 if (!rc)
497 dlpar_release_drc(drc_index);
498
499 return saved_rc;
500 }
501
502 pr_debug("Successfully added CPU %pOFn, drc index: %x\n", dn,
503 drc_index);
504 return rc;
505 }
506
dlpar_cpu_remove(struct device_node * dn,u32 drc_index)507 static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
508 {
509 int rc;
510
511 pr_debug("Attempting to remove CPU %pOFn, drc index: %x\n",
512 dn, drc_index);
513
514 rc = dlpar_offline_cpu(dn);
515 if (rc) {
516 pr_warn("Failed to offline CPU %pOFn, rc: %d\n", dn, rc);
517 return -EINVAL;
518 }
519
520 rc = dlpar_release_drc(drc_index);
521 if (rc) {
522 pr_warn("Failed to release drc (%x) for CPU %pOFn, rc: %d\n",
523 drc_index, dn, rc);
524 dlpar_online_cpu(dn);
525 return rc;
526 }
527
528 rc = dlpar_detach_node(dn);
529 if (rc) {
530 int saved_rc = rc;
531
532 pr_warn("Failed to detach CPU %pOFn, rc: %d", dn, rc);
533
534 rc = dlpar_acquire_drc(drc_index);
535 if (!rc)
536 dlpar_online_cpu(dn);
537
538 return saved_rc;
539 }
540
541 pr_debug("Successfully removed CPU, drc index: %x\n", drc_index);
542 return 0;
543 }
544
cpu_drc_index_to_dn(u32 drc_index)545 static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
546 {
547 struct device_node *dn;
548 u32 my_index;
549 int rc;
550
551 for_each_node_by_type(dn, "cpu") {
552 rc = of_property_read_u32(dn, "ibm,my-drc-index", &my_index);
553 if (rc)
554 continue;
555
556 if (my_index == drc_index)
557 break;
558 }
559
560 return dn;
561 }
562
dlpar_cpu_remove_by_index(u32 drc_index)563 static int dlpar_cpu_remove_by_index(u32 drc_index)
564 {
565 struct device_node *dn;
566 int rc;
567
568 dn = cpu_drc_index_to_dn(drc_index);
569 if (!dn) {
570 pr_warn("Cannot find CPU (drc index %x) to remove\n",
571 drc_index);
572 return -ENODEV;
573 }
574
575 rc = dlpar_cpu_remove(dn, drc_index);
576 of_node_put(dn);
577 return rc;
578 }
579
find_dlpar_cpus_to_remove(u32 * cpu_drcs,int cpus_to_remove)580 static int find_dlpar_cpus_to_remove(u32 *cpu_drcs, int cpus_to_remove)
581 {
582 struct device_node *dn;
583 int cpus_found = 0;
584 int rc;
585
586 /* We want to find cpus_to_remove + 1 CPUs to ensure we do not
587 * remove the last CPU.
588 */
589 for_each_node_by_type(dn, "cpu") {
590 cpus_found++;
591
592 if (cpus_found > cpus_to_remove) {
593 of_node_put(dn);
594 break;
595 }
596
597 /* Note that cpus_found is always 1 ahead of the index
598 * into the cpu_drcs array, so we use cpus_found - 1
599 */
600 rc = of_property_read_u32(dn, "ibm,my-drc-index",
601 &cpu_drcs[cpus_found - 1]);
602 if (rc) {
603 pr_warn("Error occurred getting drc-index for %pOFn\n",
604 dn);
605 of_node_put(dn);
606 return -1;
607 }
608 }
609
610 if (cpus_found < cpus_to_remove) {
611 pr_warn("Failed to find enough CPUs (%d of %d) to remove\n",
612 cpus_found, cpus_to_remove);
613 } else if (cpus_found == cpus_to_remove) {
614 pr_warn("Cannot remove all CPUs\n");
615 }
616
617 return cpus_found;
618 }
619
dlpar_cpu_remove_by_count(u32 cpus_to_remove)620 static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
621 {
622 u32 *cpu_drcs;
623 int cpus_found;
624 int cpus_removed = 0;
625 int i, rc;
626
627 pr_debug("Attempting to hot-remove %d CPUs\n", cpus_to_remove);
628
629 cpu_drcs = kcalloc(cpus_to_remove, sizeof(*cpu_drcs), GFP_KERNEL);
630 if (!cpu_drcs)
631 return -EINVAL;
632
633 cpus_found = find_dlpar_cpus_to_remove(cpu_drcs, cpus_to_remove);
634 if (cpus_found <= cpus_to_remove) {
635 kfree(cpu_drcs);
636 return -EINVAL;
637 }
638
639 for (i = 0; i < cpus_to_remove; i++) {
640 rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
641 if (rc)
642 break;
643
644 cpus_removed++;
645 }
646
647 if (cpus_removed != cpus_to_remove) {
648 pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
649
650 for (i = 0; i < cpus_removed; i++)
651 dlpar_cpu_add(cpu_drcs[i]);
652
653 rc = -EINVAL;
654 } else {
655 rc = 0;
656 }
657
658 kfree(cpu_drcs);
659 return rc;
660 }
661
find_drc_info_cpus_to_add(struct device_node * cpus,struct property * info,u32 * cpu_drcs,u32 cpus_to_add)662 static int find_drc_info_cpus_to_add(struct device_node *cpus,
663 struct property *info,
664 u32 *cpu_drcs, u32 cpus_to_add)
665 {
666 struct of_drc_info drc;
667 const __be32 *value;
668 u32 count, drc_index;
669 int cpus_found = 0;
670 int i, j;
671
672 if (!info)
673 return -1;
674
675 value = of_prop_next_u32(info, NULL, &count);
676 if (value)
677 value++;
678
679 for (i = 0; i < count; i++) {
680 of_read_drc_info_cell(&info, &value, &drc);
681 if (strncmp(drc.drc_type, "CPU", 3))
682 break;
683
684 drc_index = drc.drc_index_start;
685 for (j = 0; j < drc.num_sequential_elems; j++) {
686 if (dlpar_cpu_exists(cpus, drc_index))
687 continue;
688
689 cpu_drcs[cpus_found++] = drc_index;
690
691 if (cpus_found == cpus_to_add)
692 return cpus_found;
693
694 drc_index += drc.sequential_inc;
695 }
696 }
697
698 return cpus_found;
699 }
700
find_drc_index_cpus_to_add(struct device_node * cpus,u32 * cpu_drcs,u32 cpus_to_add)701 static int find_drc_index_cpus_to_add(struct device_node *cpus,
702 u32 *cpu_drcs, u32 cpus_to_add)
703 {
704 int cpus_found = 0;
705 int index, rc;
706 u32 drc_index;
707
708 /* Search the ibm,drc-indexes array for possible CPU drcs to
709 * add. Note that the format of the ibm,drc-indexes array is
710 * the number of entries in the array followed by the array
711 * of drc values so we start looking at index = 1.
712 */
713 index = 1;
714 while (cpus_found < cpus_to_add) {
715 rc = of_property_read_u32_index(cpus, "ibm,drc-indexes",
716 index++, &drc_index);
717
718 if (rc)
719 break;
720
721 if (dlpar_cpu_exists(cpus, drc_index))
722 continue;
723
724 cpu_drcs[cpus_found++] = drc_index;
725 }
726
727 return cpus_found;
728 }
729
dlpar_cpu_add_by_count(u32 cpus_to_add)730 static int dlpar_cpu_add_by_count(u32 cpus_to_add)
731 {
732 struct device_node *parent;
733 struct property *info;
734 u32 *cpu_drcs;
735 int cpus_added = 0;
736 int cpus_found;
737 int i, rc;
738
739 pr_debug("Attempting to hot-add %d CPUs\n", cpus_to_add);
740
741 cpu_drcs = kcalloc(cpus_to_add, sizeof(*cpu_drcs), GFP_KERNEL);
742 if (!cpu_drcs)
743 return -EINVAL;
744
745 parent = of_find_node_by_path("/cpus");
746 if (!parent) {
747 pr_warn("Could not find CPU root node in device tree\n");
748 kfree(cpu_drcs);
749 return -1;
750 }
751
752 info = of_find_property(parent, "ibm,drc-info", NULL);
753 if (info)
754 cpus_found = find_drc_info_cpus_to_add(parent, info, cpu_drcs, cpus_to_add);
755 else
756 cpus_found = find_drc_index_cpus_to_add(parent, cpu_drcs, cpus_to_add);
757
758 of_node_put(parent);
759
760 if (cpus_found < cpus_to_add) {
761 pr_warn("Failed to find enough CPUs (%d of %d) to add\n",
762 cpus_found, cpus_to_add);
763 kfree(cpu_drcs);
764 return -EINVAL;
765 }
766
767 for (i = 0; i < cpus_to_add; i++) {
768 rc = dlpar_cpu_add(cpu_drcs[i]);
769 if (rc)
770 break;
771
772 cpus_added++;
773 }
774
775 if (cpus_added < cpus_to_add) {
776 pr_warn("CPU hot-add failed, removing any added CPUs\n");
777
778 for (i = 0; i < cpus_added; i++)
779 dlpar_cpu_remove_by_index(cpu_drcs[i]);
780
781 rc = -EINVAL;
782 } else {
783 rc = 0;
784 }
785
786 kfree(cpu_drcs);
787 return rc;
788 }
789
dlpar_cpu(struct pseries_hp_errorlog * hp_elog)790 int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
791 {
792 u32 count, drc_index;
793 int rc;
794
795 count = hp_elog->_drc_u.drc_count;
796 drc_index = hp_elog->_drc_u.drc_index;
797
798 lock_device_hotplug();
799
800 switch (hp_elog->action) {
801 case PSERIES_HP_ELOG_ACTION_REMOVE:
802 if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
803 rc = dlpar_cpu_remove_by_count(count);
804 else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
805 rc = dlpar_cpu_remove_by_index(drc_index);
806 else
807 rc = -EINVAL;
808 break;
809 case PSERIES_HP_ELOG_ACTION_ADD:
810 if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
811 rc = dlpar_cpu_add_by_count(count);
812 else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
813 rc = dlpar_cpu_add(drc_index);
814 else
815 rc = -EINVAL;
816 break;
817 default:
818 pr_err("Invalid action (%d) specified\n", hp_elog->action);
819 rc = -EINVAL;
820 break;
821 }
822
823 unlock_device_hotplug();
824 return rc;
825 }
826
827 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
828
dlpar_cpu_probe(const char * buf,size_t count)829 static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
830 {
831 u32 drc_index;
832 int rc;
833
834 rc = kstrtou32(buf, 0, &drc_index);
835 if (rc)
836 return -EINVAL;
837
838 rc = dlpar_cpu_add(drc_index);
839
840 return rc ? rc : count;
841 }
842
dlpar_cpu_release(const char * buf,size_t count)843 static ssize_t dlpar_cpu_release(const char *buf, size_t count)
844 {
845 struct device_node *dn;
846 u32 drc_index;
847 int rc;
848
849 dn = of_find_node_by_path(buf);
850 if (!dn)
851 return -EINVAL;
852
853 rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
854 if (rc) {
855 of_node_put(dn);
856 return -EINVAL;
857 }
858
859 rc = dlpar_cpu_remove(dn, drc_index);
860 of_node_put(dn);
861
862 return rc ? rc : count;
863 }
864
865 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
866
pseries_smp_notifier(struct notifier_block * nb,unsigned long action,void * data)867 static int pseries_smp_notifier(struct notifier_block *nb,
868 unsigned long action, void *data)
869 {
870 struct of_reconfig_data *rd = data;
871 int err = 0;
872
873 switch (action) {
874 case OF_RECONFIG_ATTACH_NODE:
875 err = pseries_add_processor(rd->dn);
876 break;
877 case OF_RECONFIG_DETACH_NODE:
878 pseries_remove_processor(rd->dn);
879 break;
880 }
881 return notifier_from_errno(err);
882 }
883
884 static struct notifier_block pseries_smp_nb = {
885 .notifier_call = pseries_smp_notifier,
886 };
887
pseries_cpu_hotplug_init(void)888 static int __init pseries_cpu_hotplug_init(void)
889 {
890 int qcss_tok;
891
892 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
893 ppc_md.cpu_probe = dlpar_cpu_probe;
894 ppc_md.cpu_release = dlpar_cpu_release;
895 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
896
897 rtas_stop_self_token = rtas_token("stop-self");
898 qcss_tok = rtas_token("query-cpu-stopped-state");
899
900 if (rtas_stop_self_token == RTAS_UNKNOWN_SERVICE ||
901 qcss_tok == RTAS_UNKNOWN_SERVICE) {
902 printk(KERN_INFO "CPU Hotplug not supported by firmware "
903 "- disabling.\n");
904 return 0;
905 }
906
907 smp_ops->cpu_offline_self = pseries_cpu_offline_self;
908 smp_ops->cpu_disable = pseries_cpu_disable;
909 smp_ops->cpu_die = pseries_cpu_die;
910
911 /* Processors can be added/removed only on LPAR */
912 if (firmware_has_feature(FW_FEATURE_LPAR))
913 of_reconfig_notifier_register(&pseries_smp_nb);
914
915 return 0;
916 }
917 machine_arch_initcall(pseries, pseries_cpu_hotplug_init);
918