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 */
40static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
41
42/*
43 * Record the CPU ids used on each nodes.
44 * Protected by cpu_add_remove_lock.
45 */
46static cpumask_var_t node_recorded_ids_map[MAX_NUMNODES];
47
48static void rtas_stop_self(void)
49{
50 static struct rtas_args args;
51
52 local_irq_disable();
53
54 BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
55
56 rtas_call_unlocked(&args, rtas_stop_self_token, 0, 1, NULL);
57
58 panic(fmt: "Alas, I survived.\n");
59}
60
61static void pseries_cpu_offline_self(void)
62{
63 unsigned int hwcpu = hard_smp_processor_id();
64
65 local_irq_disable();
66 idle_task_exit();
67 if (xive_enabled())
68 xive_teardown_cpu();
69 else
70 xics_teardown_cpu();
71
72 unregister_slb_shadow(hwcpu);
73 unregister_vpa(hwcpu);
74 rtas_stop_self();
75
76 /* Should never get here... */
77 BUG();
78 for(;;);
79}
80
81static int pseries_cpu_disable(void)
82{
83 int cpu = smp_processor_id();
84
85 set_cpu_online(cpu, online: false);
86 vdso_data->processorCount--;
87
88 /*fix boot_cpuid here*/
89 if (cpu == boot_cpuid)
90 boot_cpuid = cpumask_any(cpu_online_mask);
91
92 /* FIXME: abstract this to not be platform specific later on */
93 if (xive_enabled())
94 xive_smp_disable_cpu();
95 else
96 xics_migrate_irqs_away();
97
98 cleanup_cpu_mmu_context();
99
100 return 0;
101}
102
103/*
104 * pseries_cpu_die: Wait for the cpu to die.
105 * @cpu: logical processor id of the CPU whose death we're awaiting.
106 *
107 * This function is called from the context of the thread which is performing
108 * the cpu-offline. Here we wait for long enough to allow the cpu in question
109 * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
110 * notifications.
111 *
112 * OTOH, pseries_cpu_offline_self() is called by the @cpu when it wants to
113 * self-destruct.
114 */
115static void pseries_cpu_die(unsigned int cpu)
116{
117 int cpu_status = 1;
118 unsigned int pcpu = get_hard_smp_processor_id(cpu);
119 unsigned long timeout = jiffies + msecs_to_jiffies(m: 120000);
120
121 while (true) {
122 cpu_status = smp_query_cpu_stopped(pcpu);
123 if (cpu_status == QCSS_STOPPED ||
124 cpu_status == QCSS_HARDWARE_ERROR)
125 break;
126
127 if (time_after(jiffies, timeout)) {
128 pr_warn("CPU %i (hwid %i) didn't die after 120 seconds\n",
129 cpu, pcpu);
130 timeout = jiffies + msecs_to_jiffies(m: 120000);
131 }
132
133 cond_resched();
134 }
135
136 if (cpu_status == QCSS_HARDWARE_ERROR) {
137 pr_warn("CPU %i (hwid %i) reported error while dying\n",
138 cpu, pcpu);
139 }
140
141 paca_ptrs[cpu]->cpu_start = 0;
142}
143
144/**
145 * find_cpu_id_range - found a linear ranger of @nthreads free CPU ids.
146 * @nthreads : the number of threads (cpu ids)
147 * @assigned_node : the node it belongs to or NUMA_NO_NODE if free ids from any
148 * node can be peek.
149 * @cpu_mask: the returned CPU mask.
150 *
151 * Returns 0 on success.
152 */
153static int find_cpu_id_range(unsigned int nthreads, int assigned_node,
154 cpumask_var_t *cpu_mask)
155{
156 cpumask_var_t candidate_mask;
157 unsigned int cpu, node;
158 int rc = -ENOSPC;
159
160 if (!zalloc_cpumask_var(mask: &candidate_mask, GFP_KERNEL))
161 return -ENOMEM;
162
163 cpumask_clear(dstp: *cpu_mask);
164 for (cpu = 0; cpu < nthreads; cpu++)
165 cpumask_set_cpu(cpu, dstp: *cpu_mask);
166
167 BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask));
168
169 /* Get a bitmap of unoccupied slots. */
170 cpumask_xor(dstp: candidate_mask, cpu_possible_mask, cpu_present_mask);
171
172 if (assigned_node != NUMA_NO_NODE) {
173 /*
174 * Remove free ids previously assigned on the other nodes. We
175 * can walk only online nodes because once a node became online
176 * it is not turned offlined back.
177 */
178 for_each_online_node(node) {
179 if (node == assigned_node)
180 continue;
181 cpumask_andnot(dstp: candidate_mask, src1p: candidate_mask,
182 src2p: node_recorded_ids_map[node]);
183 }
184 }
185
186 if (cpumask_empty(srcp: candidate_mask))
187 goto out;
188
189 while (!cpumask_empty(srcp: *cpu_mask)) {
190 if (cpumask_subset(src1p: *cpu_mask, src2p: candidate_mask))
191 /* Found a range where we can insert the new cpu(s) */
192 break;
193 cpumask_shift_left(dstp: *cpu_mask, srcp: *cpu_mask, n: nthreads);
194 }
195
196 if (!cpumask_empty(srcp: *cpu_mask))
197 rc = 0;
198
199out:
200 free_cpumask_var(mask: candidate_mask);
201 return rc;
202}
203
204/*
205 * Update cpu_present_mask and paca(s) for a new cpu node. The wrinkle
206 * here is that a cpu device node may represent multiple logical cpus
207 * in the SMT case. We must honor the assumption in other code that
208 * the logical ids for sibling SMT threads x and y are adjacent, such
209 * that x^1 == y and y^1 == x.
210 */
211static int pseries_add_processor(struct device_node *np)
212{
213 int len, nthreads, node, cpu, assigned_node;
214 int rc = 0;
215 cpumask_var_t cpu_mask;
216 const __be32 *intserv;
217
218 intserv = of_get_property(node: np, name: "ibm,ppc-interrupt-server#s", lenp: &len);
219 if (!intserv)
220 return 0;
221
222 nthreads = len / sizeof(u32);
223
224 if (!alloc_cpumask_var(mask: &cpu_mask, GFP_KERNEL))
225 return -ENOMEM;
226
227 /*
228 * Fetch from the DT nodes read by dlpar_configure_connector() the NUMA
229 * node id the added CPU belongs to.
230 */
231 node = of_node_to_nid(np);
232 if (node < 0 || !node_possible(node))
233 node = first_online_node;
234
235 BUG_ON(node == NUMA_NO_NODE);
236 assigned_node = node;
237
238 cpu_maps_update_begin();
239
240 rc = find_cpu_id_range(nthreads, assigned_node: node, cpu_mask: &cpu_mask);
241 if (rc && nr_node_ids > 1) {
242 /*
243 * Try again, considering the free CPU ids from the other node.
244 */
245 node = NUMA_NO_NODE;
246 rc = find_cpu_id_range(nthreads, NUMA_NO_NODE, cpu_mask: &cpu_mask);
247 }
248
249 if (rc) {
250 pr_err("Cannot add cpu %pOF; this system configuration"
251 " supports %d logical cpus.\n", np, num_possible_cpus());
252 goto out;
253 }
254
255 for_each_cpu(cpu, cpu_mask) {
256 BUG_ON(cpu_present(cpu));
257 set_cpu_present(cpu, present: true);
258 set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv++));
259 }
260
261 /* Record the newly used CPU ids for the associate node. */
262 cpumask_or(dstp: node_recorded_ids_map[assigned_node],
263 src1p: node_recorded_ids_map[assigned_node], src2p: cpu_mask);
264
265 /*
266 * If node is set to NUMA_NO_NODE, CPU ids have be reused from
267 * another node, remove them from its mask.
268 */
269 if (node == NUMA_NO_NODE) {
270 cpu = cpumask_first(srcp: cpu_mask);
271 pr_warn("Reusing free CPU ids %d-%d from another node\n",
272 cpu, cpu + nthreads - 1);
273 for_each_online_node(node) {
274 if (node == assigned_node)
275 continue;
276 cpumask_andnot(dstp: node_recorded_ids_map[node],
277 src1p: node_recorded_ids_map[node],
278 src2p: cpu_mask);
279 }
280 }
281
282out:
283 cpu_maps_update_done();
284 free_cpumask_var(mask: cpu_mask);
285 return rc;
286}
287
288/*
289 * Update the present map for a cpu node which is going away, and set
290 * the hard id in the paca(s) to -1 to be consistent with boot time
291 * convention for non-present cpus.
292 */
293static void pseries_remove_processor(struct device_node *np)
294{
295 unsigned int cpu;
296 int len, nthreads, i;
297 const __be32 *intserv;
298 u32 thread;
299
300 intserv = of_get_property(node: np, name: "ibm,ppc-interrupt-server#s", lenp: &len);
301 if (!intserv)
302 return;
303
304 nthreads = len / sizeof(u32);
305
306 cpu_maps_update_begin();
307 for (i = 0; i < nthreads; i++) {
308 thread = be32_to_cpu(intserv[i]);
309 for_each_present_cpu(cpu) {
310 if (get_hard_smp_processor_id(cpu) != thread)
311 continue;
312 BUG_ON(cpu_online(cpu));
313 set_cpu_present(cpu, present: false);
314 set_hard_smp_processor_id(cpu, -1);
315 update_numa_cpu_lookup_table(cpu, -1);
316 break;
317 }
318 if (cpu >= nr_cpu_ids)
319 printk(KERN_WARNING "Could not find cpu to remove "
320 "with physical id 0x%x\n", thread);
321 }
322 cpu_maps_update_done();
323}
324
325static int dlpar_offline_cpu(struct device_node *dn)
326{
327 int rc = 0;
328 unsigned int cpu;
329 int len, nthreads, i;
330 const __be32 *intserv;
331 u32 thread;
332
333 intserv = of_get_property(node: dn, name: "ibm,ppc-interrupt-server#s", lenp: &len);
334 if (!intserv)
335 return -EINVAL;
336
337 nthreads = len / sizeof(u32);
338
339 cpu_maps_update_begin();
340 for (i = 0; i < nthreads; i++) {
341 thread = be32_to_cpu(intserv[i]);
342 for_each_present_cpu(cpu) {
343 if (get_hard_smp_processor_id(cpu) != thread)
344 continue;
345
346 if (!cpu_online(cpu))
347 break;
348
349 /*
350 * device_offline() will return -EBUSY (via cpu_down()) if there
351 * is only one CPU left. Check it here to fail earlier and with a
352 * more informative error message, while also retaining the
353 * cpu_add_remove_lock to be sure that no CPUs are being
354 * online/offlined during this check.
355 */
356 if (num_online_cpus() == 1) {
357 pr_warn("Unable to remove last online CPU %pOFn\n", dn);
358 rc = -EBUSY;
359 goto out_unlock;
360 }
361
362 cpu_maps_update_done();
363 rc = device_offline(dev: get_cpu_device(cpu));
364 if (rc)
365 goto out;
366 cpu_maps_update_begin();
367 break;
368 }
369 if (cpu == num_possible_cpus()) {
370 pr_warn("Could not find cpu to offline with physical id 0x%x\n",
371 thread);
372 }
373 }
374out_unlock:
375 cpu_maps_update_done();
376
377out:
378 return rc;
379}
380
381static int dlpar_online_cpu(struct device_node *dn)
382{
383 int rc = 0;
384 unsigned int cpu;
385 int len, nthreads, i;
386 const __be32 *intserv;
387 u32 thread;
388
389 intserv = of_get_property(node: dn, name: "ibm,ppc-interrupt-server#s", lenp: &len);
390 if (!intserv)
391 return -EINVAL;
392
393 nthreads = len / sizeof(u32);
394
395 cpu_maps_update_begin();
396 for (i = 0; i < nthreads; i++) {
397 thread = be32_to_cpu(intserv[i]);
398 for_each_present_cpu(cpu) {
399 if (get_hard_smp_processor_id(cpu) != thread)
400 continue;
401
402 if (!topology_is_primary_thread(cpu)) {
403 if (cpu_smt_control != CPU_SMT_ENABLED)
404 break;
405 if (!topology_smt_thread_allowed(cpu))
406 break;
407 }
408
409 cpu_maps_update_done();
410 find_and_update_cpu_nid(cpu);
411 rc = device_online(dev: get_cpu_device(cpu));
412 if (rc) {
413 dlpar_offline_cpu(dn);
414 goto out;
415 }
416 cpu_maps_update_begin();
417
418 break;
419 }
420 if (cpu == num_possible_cpus())
421 printk(KERN_WARNING "Could not find cpu to online "
422 "with physical id 0x%x\n", thread);
423 }
424 cpu_maps_update_done();
425
426out:
427 return rc;
428
429}
430
431static bool dlpar_cpu_exists(struct device_node *parent, u32 drc_index)
432{
433 struct device_node *child = NULL;
434 u32 my_drc_index;
435 bool found;
436 int rc;
437
438 /* Assume cpu doesn't exist */
439 found = false;
440
441 for_each_child_of_node(parent, child) {
442 rc = of_property_read_u32(np: child, propname: "ibm,my-drc-index",
443 out_value: &my_drc_index);
444 if (rc)
445 continue;
446
447 if (my_drc_index == drc_index) {
448 of_node_put(node: child);
449 found = true;
450 break;
451 }
452 }
453
454 return found;
455}
456
457static bool drc_info_valid_index(struct device_node *parent, u32 drc_index)
458{
459 struct property *info;
460 struct of_drc_info drc;
461 const __be32 *value;
462 u32 index;
463 int count, i, j;
464
465 info = of_find_property(np: parent, name: "ibm,drc-info", NULL);
466 if (!info)
467 return false;
468
469 value = of_prop_next_u32(prop: info, NULL, pu: &count);
470
471 /* First value of ibm,drc-info is number of drc-info records */
472 if (value)
473 value++;
474 else
475 return false;
476
477 for (i = 0; i < count; i++) {
478 if (of_read_drc_info_cell(&info, &value, &drc))
479 return false;
480
481 if (strncmp(drc.drc_type, "CPU", 3))
482 break;
483
484 if (drc_index > drc.last_drc_index)
485 continue;
486
487 index = drc.drc_index_start;
488 for (j = 0; j < drc.num_sequential_elems; j++) {
489 if (drc_index == index)
490 return true;
491
492 index += drc.sequential_inc;
493 }
494 }
495
496 return false;
497}
498
499static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
500{
501 bool found = false;
502 int rc, index;
503
504 if (of_property_present(np: parent, propname: "ibm,drc-info"))
505 return drc_info_valid_index(parent, drc_index);
506
507 /* Note that the format of the ibm,drc-indexes array is
508 * the number of entries in the array followed by the array
509 * of drc values so we start looking at index = 1.
510 */
511 index = 1;
512 while (!found) {
513 u32 drc;
514
515 rc = of_property_read_u32_index(np: parent, propname: "ibm,drc-indexes",
516 index: index++, out_value: &drc);
517
518 if (rc)
519 break;
520
521 if (drc == drc_index)
522 found = true;
523 }
524
525 return found;
526}
527
528static int pseries_cpuhp_attach_nodes(struct device_node *dn)
529{
530 struct of_changeset cs;
531 int ret;
532
533 /*
534 * This device node is unattached but may have siblings; open-code the
535 * traversal.
536 */
537 for (of_changeset_init(ocs: &cs); dn != NULL; dn = dn->sibling) {
538 ret = of_changeset_attach_node(ocs: &cs, np: dn);
539 if (ret)
540 goto out;
541 }
542
543 ret = of_changeset_apply(ocs: &cs);
544out:
545 of_changeset_destroy(ocs: &cs);
546 return ret;
547}
548
549static ssize_t dlpar_cpu_add(u32 drc_index)
550{
551 struct device_node *dn, *parent;
552 int rc, saved_rc;
553
554 pr_debug("Attempting to add CPU, drc index: %x\n", drc_index);
555
556 parent = of_find_node_by_path(path: "/cpus");
557 if (!parent) {
558 pr_warn("Failed to find CPU root node \"/cpus\"\n");
559 return -ENODEV;
560 }
561
562 if (dlpar_cpu_exists(parent, drc_index)) {
563 of_node_put(node: parent);
564 pr_warn("CPU with drc index %x already exists\n", drc_index);
565 return -EINVAL;
566 }
567
568 if (!valid_cpu_drc_index(parent, drc_index)) {
569 of_node_put(node: parent);
570 pr_warn("Cannot find CPU (drc index %x) to add.\n", drc_index);
571 return -EINVAL;
572 }
573
574 rc = dlpar_acquire_drc(drc_index);
575 if (rc) {
576 pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
577 rc, drc_index);
578 of_node_put(node: parent);
579 return -EINVAL;
580 }
581
582 dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
583 if (!dn) {
584 pr_warn("Failed call to configure-connector, drc index: %x\n",
585 drc_index);
586 dlpar_release_drc(drc_index);
587 of_node_put(node: parent);
588 return -EINVAL;
589 }
590
591 rc = pseries_cpuhp_attach_nodes(dn);
592
593 /* Regardless we are done with parent now */
594 of_node_put(node: parent);
595
596 if (rc) {
597 saved_rc = rc;
598 pr_warn("Failed to attach node %pOFn, rc: %d, drc index: %x\n",
599 dn, rc, drc_index);
600
601 rc = dlpar_release_drc(drc_index);
602 if (!rc)
603 dlpar_free_cc_nodes(dn);
604
605 return saved_rc;
606 }
607
608 update_numa_distance(dn);
609
610 rc = dlpar_online_cpu(dn);
611 if (rc) {
612 saved_rc = rc;
613 pr_warn("Failed to online cpu %pOFn, rc: %d, drc index: %x\n",
614 dn, rc, drc_index);
615
616 rc = dlpar_detach_node(dn);
617 if (!rc)
618 dlpar_release_drc(drc_index);
619
620 return saved_rc;
621 }
622
623 pr_debug("Successfully added CPU %pOFn, drc index: %x\n", dn,
624 drc_index);
625 return rc;
626}
627
628static unsigned int pseries_cpuhp_cache_use_count(const struct device_node *cachedn)
629{
630 unsigned int use_count = 0;
631 struct device_node *dn, *tn;
632
633 WARN_ON(!of_node_is_type(cachedn, "cache"));
634
635 for_each_of_cpu_node(dn) {
636 tn = of_find_next_cache_node(dn);
637 of_node_put(node: tn);
638 if (tn == cachedn)
639 use_count++;
640 }
641
642 for_each_node_by_type(dn, "cache") {
643 tn = of_find_next_cache_node(dn);
644 of_node_put(node: tn);
645 if (tn == cachedn)
646 use_count++;
647 }
648
649 return use_count;
650}
651
652static int pseries_cpuhp_detach_nodes(struct device_node *cpudn)
653{
654 struct device_node *dn;
655 struct of_changeset cs;
656 int ret = 0;
657
658 of_changeset_init(ocs: &cs);
659 ret = of_changeset_detach_node(ocs: &cs, np: cpudn);
660 if (ret)
661 goto out;
662
663 dn = cpudn;
664 while ((dn = of_find_next_cache_node(dn))) {
665 if (pseries_cpuhp_cache_use_count(cachedn: dn) > 1) {
666 of_node_put(node: dn);
667 break;
668 }
669
670 ret = of_changeset_detach_node(ocs: &cs, np: dn);
671 of_node_put(node: dn);
672 if (ret)
673 goto out;
674 }
675
676 ret = of_changeset_apply(ocs: &cs);
677out:
678 of_changeset_destroy(ocs: &cs);
679 return ret;
680}
681
682static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
683{
684 int rc;
685
686 pr_debug("Attempting to remove CPU %pOFn, drc index: %x\n",
687 dn, drc_index);
688
689 rc = dlpar_offline_cpu(dn);
690 if (rc) {
691 pr_warn("Failed to offline CPU %pOFn, rc: %d\n", dn, rc);
692 return -EINVAL;
693 }
694
695 rc = dlpar_release_drc(drc_index);
696 if (rc) {
697 pr_warn("Failed to release drc (%x) for CPU %pOFn, rc: %d\n",
698 drc_index, dn, rc);
699 dlpar_online_cpu(dn);
700 return rc;
701 }
702
703 rc = pseries_cpuhp_detach_nodes(cpudn: dn);
704 if (rc) {
705 int saved_rc = rc;
706
707 pr_warn("Failed to detach CPU %pOFn, rc: %d", dn, rc);
708
709 rc = dlpar_acquire_drc(drc_index);
710 if (!rc)
711 dlpar_online_cpu(dn);
712
713 return saved_rc;
714 }
715
716 pr_debug("Successfully removed CPU, drc index: %x\n", drc_index);
717 return 0;
718}
719
720static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
721{
722 struct device_node *dn;
723 u32 my_index;
724 int rc;
725
726 for_each_node_by_type(dn, "cpu") {
727 rc = of_property_read_u32(np: dn, propname: "ibm,my-drc-index", out_value: &my_index);
728 if (rc)
729 continue;
730
731 if (my_index == drc_index)
732 break;
733 }
734
735 return dn;
736}
737
738static int dlpar_cpu_remove_by_index(u32 drc_index)
739{
740 struct device_node *dn;
741 int rc;
742
743 dn = cpu_drc_index_to_dn(drc_index);
744 if (!dn) {
745 pr_warn("Cannot find CPU (drc index %x) to remove\n",
746 drc_index);
747 return -ENODEV;
748 }
749
750 rc = dlpar_cpu_remove(dn, drc_index);
751 of_node_put(node: dn);
752 return rc;
753}
754
755int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
756{
757 u32 drc_index;
758 int rc;
759
760 drc_index = hp_elog->_drc_u.drc_index;
761
762 lock_device_hotplug();
763
764 switch (hp_elog->action) {
765 case PSERIES_HP_ELOG_ACTION_REMOVE:
766 if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) {
767 rc = dlpar_cpu_remove_by_index(drc_index);
768 /*
769 * Setting the isolation state of an UNISOLATED/CONFIGURED
770 * device to UNISOLATE is a no-op, but the hypervisor can
771 * use it as a hint that the CPU removal failed.
772 */
773 if (rc)
774 dlpar_unisolate_drc(drc_index);
775 }
776 else
777 rc = -EINVAL;
778 break;
779 case PSERIES_HP_ELOG_ACTION_ADD:
780 if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
781 rc = dlpar_cpu_add(drc_index);
782 else
783 rc = -EINVAL;
784 break;
785 default:
786 pr_err("Invalid action (%d) specified\n", hp_elog->action);
787 rc = -EINVAL;
788 break;
789 }
790
791 unlock_device_hotplug();
792 return rc;
793}
794
795#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
796
797static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
798{
799 u32 drc_index;
800 int rc;
801
802 rc = kstrtou32(buf, 0, &drc_index);
803 if (rc)
804 return -EINVAL;
805
806 rc = dlpar_cpu_add(drc_index);
807
808 return rc ? rc : count;
809}
810
811static ssize_t dlpar_cpu_release(const char *buf, size_t count)
812{
813 struct device_node *dn;
814 u32 drc_index;
815 int rc;
816
817 dn = of_find_node_by_path(buf);
818 if (!dn)
819 return -EINVAL;
820
821 rc = of_property_read_u32(dn, "ibm,my-drc-index", &drc_index);
822 if (rc) {
823 of_node_put(dn);
824 return -EINVAL;
825 }
826
827 rc = dlpar_cpu_remove(dn, drc_index);
828 of_node_put(dn);
829
830 return rc ? rc : count;
831}
832
833#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
834
835static int pseries_smp_notifier(struct notifier_block *nb,
836 unsigned long action, void *data)
837{
838 struct of_reconfig_data *rd = data;
839 int err = 0;
840
841 switch (action) {
842 case OF_RECONFIG_ATTACH_NODE:
843 err = pseries_add_processor(np: rd->dn);
844 break;
845 case OF_RECONFIG_DETACH_NODE:
846 pseries_remove_processor(np: rd->dn);
847 break;
848 }
849 return notifier_from_errno(err);
850}
851
852static struct notifier_block pseries_smp_nb = {
853 .notifier_call = pseries_smp_notifier,
854};
855
856void __init pseries_cpu_hotplug_init(void)
857{
858 int qcss_tok;
859
860 rtas_stop_self_token = rtas_function_token(RTAS_FN_STOP_SELF);
861 qcss_tok = rtas_function_token(RTAS_FN_QUERY_CPU_STOPPED_STATE);
862
863 if (rtas_stop_self_token == RTAS_UNKNOWN_SERVICE ||
864 qcss_tok == RTAS_UNKNOWN_SERVICE) {
865 printk(KERN_INFO "CPU Hotplug not supported by firmware "
866 "- disabling.\n");
867 return;
868 }
869
870 smp_ops->cpu_offline_self = pseries_cpu_offline_self;
871 smp_ops->cpu_disable = pseries_cpu_disable;
872 smp_ops->cpu_die = pseries_cpu_die;
873}
874
875static int __init pseries_dlpar_init(void)
876{
877 unsigned int node;
878
879#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
880 ppc_md.cpu_probe = dlpar_cpu_probe;
881 ppc_md.cpu_release = dlpar_cpu_release;
882#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
883
884 /* Processors can be added/removed only on LPAR */
885 if (firmware_has_feature(FW_FEATURE_LPAR)) {
886 for_each_node(node) {
887 if (!alloc_cpumask_var_node(mask: &node_recorded_ids_map[node],
888 GFP_KERNEL, node))
889 return -ENOMEM;
890
891 /* Record ids of CPU added at boot time */
892 cpumask_copy(dstp: node_recorded_ids_map[node],
893 srcp: cpumask_of_node(node));
894 }
895
896 of_reconfig_notifier_register(&pseries_smp_nb);
897 }
898
899 return 0;
900}
901machine_arch_initcall(pseries, pseries_dlpar_init);
902

source code of linux/arch/powerpc/platforms/pseries/hotplug-cpu.c