GNU Linux-libre 5.10.217-gnu1
[releases.git] / arch / powerpc / platforms / pseries / hotplug-cpu.c
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
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
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
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  */
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  */
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  */
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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);