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 /*
  43  * Record the CPU ids used on each nodes.
  44  * Protected by cpu_add_remove_lock.
  45  */
  46 static cpumask_var_t node_recorded_ids_map[MAX_NUMNODES];
  47
  48 static 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("Alas, I survived.\n");
  59 }
  60
  61 static 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
  81 static int pseries_cpu_disable(void)
  82 {
  83         int cpu = smp_processor_id();
  84
  85         set_cpu_online(cpu, 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  */
 115 static 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(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(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  */
 153 static 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(&candidate_mask, GFP_KERNEL))
 161                 return -ENOMEM;
 162
 163         cpumask_clear(*cpu_mask);
 164         for (cpu = 0; cpu < nthreads; cpu++)
 165                 cpumask_set_cpu(cpu, *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(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(candidate_mask, candidate_mask,
 182                                        node_recorded_ids_map[node]);
 183                 }
 184         }
 185
 186         if (cpumask_empty(candidate_mask))
 187                 goto out;
 188
 189         while (!cpumask_empty(*cpu_mask)) {
 190                 if (cpumask_subset(*cpu_mask, candidate_mask))
 191                         /* Found a range where we can insert the new cpu(s) */
 192                         break;
 193                 cpumask_shift_left(*cpu_mask, *cpu_mask, nthreads);
 194         }
 195
 196         if (!cpumask_empty(*cpu_mask))
 197                 rc = 0;
 198
 199 out:
 200         free_cpumask_var(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  */
 211 static 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(np, "ibm,ppc-interrupt-server#s", &len);
 219         if (!intserv)
 220                 return 0;
 221
 222         nthreads = len / sizeof(u32);
 223
 224         if (!alloc_cpumask_var(&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, node, &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);
 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, 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(node_recorded_ids_map[assigned_node],
 263                    node_recorded_ids_map[assigned_node], 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(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(node_recorded_ids_map[node],
 277                                        node_recorded_ids_map[node],
 278                                        cpu_mask);
 279                 }
 280         }
 281
 282 out:
 283         cpu_maps_update_done();
 284         free_cpumask_var(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  */
 293 static 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(np, "ibm,ppc-interrupt-server#s", &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, 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
 325 static 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(dn, "ibm,ppc-interrupt-server#s", &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(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         }
 374 out_unlock:
 375         cpu_maps_update_done();
 376
 377 out:
 378         return rc;
 379 }
 380
 381 static 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(dn, "ibm,ppc-interrupt-server#s", &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(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
 426 out:
 427         return rc;
 428
 429 }
 430
 431 static 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(child, "ibm,my-drc-index",
 443                                           &my_drc_index);
 444                 if (rc)
 445                         continue;
 446
 447                 if (my_drc_index == drc_index) {
 448                         of_node_put(child);
 449                         found = true;
 450                         break;
 451                 }
 452         }
 453
 454         return found;
 455 }
 456
 457 static 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(parent, "ibm,drc-info", NULL);
 466         if (!info)
 467                 return false;
 468
 469         value = of_prop_next_u32(info, NULL, &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
 499 static 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(parent, "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(parent, "ibm,drc-indexes",
 516                                                 index++, &drc);
 517
 518                 if (rc)
 519                         break;
 520
 521                 if (drc == drc_index)
 522                         found = true;
 523         }
 524
 525         return found;
 526 }
 527
 528 static 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(&cs); dn != NULL; dn = dn->sibling) {
 538                 ret = of_changeset_attach_node(&cs, dn);
 539                 if (ret)
 540                         goto out;
 541         }
 542
 543         ret = of_changeset_apply(&cs);
 544 out:
 545         of_changeset_destroy(&cs);
 546         return ret;
 547 }
 548
 549 static 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("/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(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(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(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(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(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
 628 static 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(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(tn);
 645                 if (tn == cachedn)
 646                         use_count++;
 647         }
 648
 649         return use_count;
 650 }
 651
 652 static 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(&cs);
 659         ret = of_changeset_detach_node(&cs, 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(dn) > 1) {
 666                         of_node_put(dn);
 667                         break;
 668                 }
 669
 670                 ret = of_changeset_detach_node(&cs, dn);
 671                 of_node_put(dn);
 672                 if (ret)
 673                         goto out;
 674         }
 675
 676         ret = of_changeset_apply(&cs);
 677 out:
 678         of_changeset_destroy(&cs);
 679         return ret;
 680 }
 681
 682 static 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(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
 720 static 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(dn, "ibm,my-drc-index", &my_index);
 728                 if (rc)
 729                         continue;
 730
 731                 if (my_index == drc_index)
 732                         break;
 733         }
 734
 735         return dn;
 736 }
 737
 738 static 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(dn);
 752         return rc;
 753 }
 754
 755 int 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
 797 static 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
 811 static 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
 835 static 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(rd->dn);
 844                 break;
 845         case OF_RECONFIG_DETACH_NODE:
 846                 pseries_remove_processor(rd->dn);
 847                 break;
 848         }
 849         return notifier_from_errno(err);
 850 }
 851
 852 static struct notifier_block pseries_smp_nb = {
 853         .notifier_call = pseries_smp_notifier,
 854 };
 855
 856 void __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
 875 static 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(&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(node_recorded_ids_map[node],
 893                                      cpumask_of_node(node));
 894                 }
 895
 896                 of_reconfig_notifier_register(&pseries_smp_nb);
 897         }
 898
 899         return 0;
 900 }
 901 machine_arch_initcall(pseries, pseries_dlpar_init);