arch/s390/kernel/topology.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Copyright IBM Corp. 2007, 2011
   4  */
   5
   6 #define KMSG_COMPONENT "cpu"
   7 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
   8
   9 #include <linux/workqueue.h>
  10 #include <linux/memblock.h>
  11 #include <linux/uaccess.h>
  12 #include <linux/sysctl.h>
  13 #include <linux/cpuset.h>
  14 #include <linux/device.h>
  15 #include <linux/export.h>
  16 #include <linux/kernel.h>
  17 #include <linux/sched.h>
  18 #include <linux/sched/topology.h>
  19 #include <linux/delay.h>
  20 #include <linux/init.h>
  21 #include <linux/slab.h>
  22 #include <linux/cpu.h>
  23 #include <linux/smp.h>
  24 #include <linux/mm.h>
  25 #include <linux/nodemask.h>
  26 #include <linux/node.h>
  27 #include <asm/hiperdispatch.h>
  28 #include <asm/sysinfo.h>
  29 #include <asm/asm.h>
  30
  31 #define PTF_HORIZONTAL  (0UL)
  32 #define PTF_VERTICAL    (1UL)
  33 #define PTF_CHECK       (2UL)
  34
  35 enum {
  36         TOPOLOGY_MODE_HW,
  37         TOPOLOGY_MODE_SINGLE,
  38         TOPOLOGY_MODE_PACKAGE,
  39         TOPOLOGY_MODE_UNINITIALIZED
  40 };
  41
  42 struct mask_info {
  43         struct mask_info *next;
  44         unsigned char id;
  45         cpumask_t mask;
  46 };
  47
  48 static int topology_mode = TOPOLOGY_MODE_UNINITIALIZED;
  49 static void set_topology_timer(void);
  50 static void topology_work_fn(struct work_struct *work);
  51 static struct sysinfo_15_1_x *tl_info;
  52 static int cpu_management;
  53
  54 static DECLARE_WORK(topology_work, topology_work_fn);
  55
  56 /*
  57  * Socket/Book linked lists and cpu_topology updates are
  58  * protected by "sched_domains_mutex".
  59  */
  60 static struct mask_info socket_info;
  61 static struct mask_info book_info;
  62 static struct mask_info drawer_info;
  63
  64 struct cpu_topology_s390 cpu_topology[NR_CPUS];
  65 EXPORT_SYMBOL_GPL(cpu_topology);
  66
  67 static void cpu_group_map(cpumask_t *dst, struct mask_info *info, unsigned int cpu)
  68 {
  69         static cpumask_t mask;
  70
  71         cpumask_clear(&mask);
  72         if (!cpumask_test_cpu(cpu, &cpu_setup_mask))
  73                 goto out;
  74         cpumask_set_cpu(cpu, &mask);
  75         switch (topology_mode) {
  76         case TOPOLOGY_MODE_HW:
  77                 while (info) {
  78                         if (cpumask_test_cpu(cpu, &info->mask)) {
  79                                 cpumask_copy(&mask, &info->mask);
  80                                 break;
  81                         }
  82                         info = info->next;
  83                 }
  84                 break;
  85         case TOPOLOGY_MODE_PACKAGE:
  86                 cpumask_copy(&mask, cpu_present_mask);
  87                 break;
  88         default:
  89                 fallthrough;
  90         case TOPOLOGY_MODE_SINGLE:
  91                 break;
  92         }
  93         cpumask_and(&mask, &mask, &cpu_setup_mask);
  94 out:
  95         cpumask_copy(dst, &mask);
  96 }
  97
  98 static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
  99 {
 100         static cpumask_t mask;
 101         unsigned int max_cpu;
 102
 103         cpumask_clear(&mask);
 104         if (!cpumask_test_cpu(cpu, &cpu_setup_mask))
 105                 goto out;
 106         cpumask_set_cpu(cpu, &mask);
 107         if (topology_mode != TOPOLOGY_MODE_HW)
 108                 goto out;
 109         cpu -= cpu % (smp_cpu_mtid + 1);
 110         max_cpu = min(cpu + smp_cpu_mtid, nr_cpu_ids - 1);
 111         for (; cpu <= max_cpu; cpu++) {
 112                 if (cpumask_test_cpu(cpu, &cpu_setup_mask))
 113                         cpumask_set_cpu(cpu, &mask);
 114         }
 115 out:
 116         cpumask_copy(dst, &mask);
 117 }
 118
 119 #define TOPOLOGY_CORE_BITS      64
 120
 121 static void add_cpus_to_mask(struct topology_core *tl_core,
 122                              struct mask_info *drawer,
 123                              struct mask_info *book,
 124                              struct mask_info *socket)
 125 {
 126         struct cpu_topology_s390 *topo;
 127         unsigned int core;
 128
 129         for_each_set_bit(core, &tl_core->mask, TOPOLOGY_CORE_BITS) {
 130                 unsigned int max_cpu, rcore;
 131                 int cpu;
 132
 133                 rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
 134                 cpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
 135                 if (cpu < 0)
 136                         continue;
 137                 max_cpu = min(cpu + smp_cpu_mtid, nr_cpu_ids - 1);
 138                 for (; cpu <= max_cpu; cpu++) {
 139                         topo = &cpu_topology[cpu];
 140                         topo->drawer_id = drawer->id;
 141                         topo->book_id = book->id;
 142                         topo->socket_id = socket->id;
 143                         topo->core_id = rcore;
 144                         topo->thread_id = cpu;
 145                         topo->dedicated = tl_core->d;
 146                         cpumask_set_cpu(cpu, &drawer->mask);
 147                         cpumask_set_cpu(cpu, &book->mask);
 148                         cpumask_set_cpu(cpu, &socket->mask);
 149                         smp_cpu_set_polarization(cpu, tl_core->pp);
 150                         smp_cpu_set_capacity(cpu, CPU_CAPACITY_HIGH);
 151                 }
 152         }
 153 }
 154
 155 static void clear_masks(void)
 156 {
 157         struct mask_info *info;
 158
 159         info = &socket_info;
 160         while (info) {
 161                 cpumask_clear(&info->mask);
 162                 info = info->next;
 163         }
 164         info = &book_info;
 165         while (info) {
 166                 cpumask_clear(&info->mask);
 167                 info = info->next;
 168         }
 169         info = &drawer_info;
 170         while (info) {
 171                 cpumask_clear(&info->mask);
 172                 info = info->next;
 173         }
 174 }
 175
 176 static union topology_entry *next_tle(union topology_entry *tle)
 177 {
 178         if (!tle->nl)
 179                 return (union topology_entry *)((struct topology_core *)tle + 1);
 180         return (union topology_entry *)((struct topology_container *)tle + 1);
 181 }
 182
 183 static void tl_to_masks(struct sysinfo_15_1_x *info)
 184 {
 185         struct mask_info *socket = &socket_info;
 186         struct mask_info *book = &book_info;
 187         struct mask_info *drawer = &drawer_info;
 188         union topology_entry *tle, *end;
 189
 190         clear_masks();
 191         tle = info->tle;
 192         end = (union topology_entry *)((unsigned long)info + info->length);
 193         while (tle < end) {
 194                 switch (tle->nl) {
 195                 case 3:
 196                         drawer = drawer->next;
 197                         drawer->id = tle->container.id;
 198                         break;
 199                 case 2:
 200                         book = book->next;
 201                         book->id = tle->container.id;
 202                         break;
 203                 case 1:
 204                         socket = socket->next;
 205                         socket->id = tle->container.id;
 206                         break;
 207                 case 0:
 208                         add_cpus_to_mask(&tle->cpu, drawer, book, socket);
 209                         break;
 210                 default:
 211                         clear_masks();
 212                         return;
 213                 }
 214                 tle = next_tle(tle);
 215         }
 216 }
 217
 218 static void topology_update_polarization_simple(void)
 219 {
 220         int cpu;
 221
 222         for_each_possible_cpu(cpu)
 223                 smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
 224 }
 225
 226 static int ptf(unsigned long fc)
 227 {
 228         int cc;
 229
 230         asm volatile(
 231                 "       .insn   rre,0xb9a20000,%[fc],%[fc]\n"
 232                 CC_IPM(cc)
 233                 : CC_OUT(cc, cc)
 234                 : [fc] "d" (fc)
 235                 : CC_CLOBBER);
 236         return CC_TRANSFORM(cc);
 237 }
 238
 239 int topology_set_cpu_management(int fc)
 240 {
 241         int cpu, rc;
 242
 243         if (!MACHINE_HAS_TOPOLOGY)
 244                 return -EOPNOTSUPP;
 245         if (fc)
 246                 rc = ptf(PTF_VERTICAL);
 247         else
 248                 rc = ptf(PTF_HORIZONTAL);
 249         if (rc)
 250                 return -EBUSY;
 251         for_each_possible_cpu(cpu)
 252                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 253         return rc;
 254 }
 255
 256 void update_cpu_masks(void)
 257 {
 258         struct cpu_topology_s390 *topo, *topo_package, *topo_sibling;
 259         int cpu, sibling, pkg_first, smt_first, id;
 260
 261         for_each_possible_cpu(cpu) {
 262                 topo = &cpu_topology[cpu];
 263                 cpu_thread_map(&topo->thread_mask, cpu);
 264                 cpu_group_map(&topo->core_mask, &socket_info, cpu);
 265                 cpu_group_map(&topo->book_mask, &book_info, cpu);
 266                 cpu_group_map(&topo->drawer_mask, &drawer_info, cpu);
 267                 topo->booted_cores = 0;
 268                 if (topology_mode != TOPOLOGY_MODE_HW) {
 269                         id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
 270                         topo->thread_id = cpu;
 271                         topo->core_id = cpu;
 272                         topo->socket_id = id;
 273                         topo->book_id = id;
 274                         topo->drawer_id = id;
 275                 }
 276         }
 277         hd_reset_state();
 278         for_each_online_cpu(cpu) {
 279                 topo = &cpu_topology[cpu];
 280                 pkg_first = cpumask_first(&topo->core_mask);
 281                 topo_package = &cpu_topology[pkg_first];
 282                 if (cpu == pkg_first) {
 283                         for_each_cpu(sibling, &topo->core_mask) {
 284                                 topo_sibling = &cpu_topology[sibling];
 285                                 smt_first = cpumask_first(&topo_sibling->thread_mask);
 286                                 if (sibling == smt_first) {
 287                                         topo_package->booted_cores++;
 288                                         hd_add_core(sibling);
 289                                 }
 290                         }
 291                 } else {
 292                         topo->booted_cores = topo_package->booted_cores;
 293                 }
 294         }
 295 }
 296
 297 void store_topology(struct sysinfo_15_1_x *info)
 298 {
 299         stsi(info, 15, 1, topology_mnest_limit());
 300 }
 301
 302 static void __arch_update_dedicated_flag(void *arg)
 303 {
 304         if (topology_cpu_dedicated(smp_processor_id()))
 305                 set_cpu_flag(CIF_DEDICATED_CPU);
 306         else
 307                 clear_cpu_flag(CIF_DEDICATED_CPU);
 308 }
 309
 310 static int __arch_update_cpu_topology(void)
 311 {
 312         struct sysinfo_15_1_x *info = tl_info;
 313         int rc, hd_status;
 314
 315         hd_status = 0;
 316         rc = 0;
 317         mutex_lock(&smp_cpu_state_mutex);
 318         if (MACHINE_HAS_TOPOLOGY) {
 319                 rc = 1;
 320                 store_topology(info);
 321                 tl_to_masks(info);
 322         }
 323         update_cpu_masks();
 324         if (!MACHINE_HAS_TOPOLOGY)
 325                 topology_update_polarization_simple();
 326         if (cpu_management == 1)
 327                 hd_status = hd_enable_hiperdispatch();
 328         mutex_unlock(&smp_cpu_state_mutex);
 329         if (hd_status == 0)
 330                 hd_disable_hiperdispatch();
 331         return rc;
 332 }
 333
 334 int arch_update_cpu_topology(void)
 335 {
 336         int rc;
 337
 338         rc = __arch_update_cpu_topology();
 339         on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
 340         return rc;
 341 }
 342
 343 static void topology_work_fn(struct work_struct *work)
 344 {
 345         rebuild_sched_domains();
 346 }
 347
 348 void topology_schedule_update(void)
 349 {
 350         schedule_work(&topology_work);
 351 }
 352
 353 static void topology_flush_work(void)
 354 {
 355         flush_work(&topology_work);
 356 }
 357
 358 static void topology_timer_fn(struct timer_list *unused)
 359 {
 360         if (ptf(PTF_CHECK))
 361                 topology_schedule_update();
 362         set_topology_timer();
 363 }
 364
 365 static struct timer_list topology_timer;
 366
 367 static atomic_t topology_poll = ATOMIC_INIT(0);
 368
 369 static void set_topology_timer(void)
 370 {
 371         if (atomic_add_unless(&topology_poll, -1, 0))
 372                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(100));
 373         else
 374                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(60 * MSEC_PER_SEC));
 375 }
 376
 377 void topology_expect_change(void)
 378 {
 379         if (!MACHINE_HAS_TOPOLOGY)
 380                 return;
 381         /* This is racy, but it doesn't matter since it is just a heuristic.
 382          * Worst case is that we poll in a higher frequency for a bit longer.
 383          */
 384         if (atomic_read(&topology_poll) > 60)
 385                 return;
 386         atomic_add(60, &topology_poll);
 387         set_topology_timer();
 388 }
 389
 390 static int set_polarization(int polarization)
 391 {
 392         int rc = 0;
 393
 394         cpus_read_lock();
 395         mutex_lock(&smp_cpu_state_mutex);
 396         if (cpu_management == polarization)
 397                 goto out;
 398         rc = topology_set_cpu_management(polarization);
 399         if (rc)
 400                 goto out;
 401         cpu_management = polarization;
 402         topology_expect_change();
 403 out:
 404         mutex_unlock(&smp_cpu_state_mutex);
 405         cpus_read_unlock();
 406         return rc;
 407 }
 408
 409 static ssize_t dispatching_show(struct device *dev,
 410                                 struct device_attribute *attr,
 411                                 char *buf)
 412 {
 413         ssize_t count;
 414
 415         mutex_lock(&smp_cpu_state_mutex);
 416         count = sysfs_emit(buf, "%d\n", cpu_management);
 417         mutex_unlock(&smp_cpu_state_mutex);
 418         return count;
 419 }
 420
 421 static ssize_t dispatching_store(struct device *dev,
 422                                  struct device_attribute *attr,
 423                                  const char *buf,
 424                                  size_t count)
 425 {
 426         int val, rc;
 427         char delim;
 428
 429         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 430                 return -EINVAL;
 431         if (val != 0 && val != 1)
 432                 return -EINVAL;
 433         rc = set_polarization(val);
 434         return rc ? rc : count;
 435 }
 436 static DEVICE_ATTR_RW(dispatching);
 437
 438 static ssize_t cpu_polarization_show(struct device *dev,
 439                                      struct device_attribute *attr, char *buf)
 440 {
 441         int cpu = dev->id;
 442         ssize_t count;
 443
 444         mutex_lock(&smp_cpu_state_mutex);
 445         switch (smp_cpu_get_polarization(cpu)) {
 446         case POLARIZATION_HRZ:
 447                 count = sysfs_emit(buf, "horizontal\n");
 448                 break;
 449         case POLARIZATION_VL:
 450                 count = sysfs_emit(buf, "vertical:low\n");
 451                 break;
 452         case POLARIZATION_VM:
 453                 count = sysfs_emit(buf, "vertical:medium\n");
 454                 break;
 455         case POLARIZATION_VH:
 456                 count = sysfs_emit(buf, "vertical:high\n");
 457                 break;
 458         default:
 459                 count = sysfs_emit(buf, "unknown\n");
 460                 break;
 461         }
 462         mutex_unlock(&smp_cpu_state_mutex);
 463         return count;
 464 }
 465 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 466
 467 static struct attribute *topology_cpu_attrs[] = {
 468         &dev_attr_polarization.attr,
 469         NULL,
 470 };
 471
 472 static struct attribute_group topology_cpu_attr_group = {
 473         .attrs = topology_cpu_attrs,
 474 };
 475
 476 static ssize_t cpu_dedicated_show(struct device *dev,
 477                                   struct device_attribute *attr, char *buf)
 478 {
 479         int cpu = dev->id;
 480         ssize_t count;
 481
 482         mutex_lock(&smp_cpu_state_mutex);
 483         count = sysfs_emit(buf, "%d\n", topology_cpu_dedicated(cpu));
 484         mutex_unlock(&smp_cpu_state_mutex);
 485         return count;
 486 }
 487 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 488
 489 static struct attribute *topology_extra_cpu_attrs[] = {
 490         &dev_attr_dedicated.attr,
 491         NULL,
 492 };
 493
 494 static struct attribute_group topology_extra_cpu_attr_group = {
 495         .attrs = topology_extra_cpu_attrs,
 496 };
 497
 498 int topology_cpu_init(struct cpu *cpu)
 499 {
 500         int rc;
 501
 502         rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 503         if (rc || !MACHINE_HAS_TOPOLOGY)
 504                 return rc;
 505         rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
 506         if (rc)
 507                 sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 508         return rc;
 509 }
 510
 511 static const struct cpumask *cpu_thread_mask(int cpu)
 512 {
 513         return &cpu_topology[cpu].thread_mask;
 514 }
 515
 516
 517 const struct cpumask *cpu_coregroup_mask(int cpu)
 518 {
 519         return &cpu_topology[cpu].core_mask;
 520 }
 521
 522 static const struct cpumask *cpu_book_mask(int cpu)
 523 {
 524         return &cpu_topology[cpu].book_mask;
 525 }
 526
 527 static const struct cpumask *cpu_drawer_mask(int cpu)
 528 {
 529         return &cpu_topology[cpu].drawer_mask;
 530 }
 531
 532 static struct sched_domain_topology_level s390_topology[] = {
 533         { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
 534         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 535         { cpu_book_mask, SD_INIT_NAME(BOOK) },
 536         { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
 537         { cpu_cpu_mask, SD_INIT_NAME(PKG) },
 538         { NULL, },
 539 };
 540
 541 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 542                                struct mask_info *mask, int offset)
 543 {
 544         int i, nr_masks;
 545
 546         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 547         for (i = 0; i < info->mnest - offset; i++)
 548                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 549         nr_masks = max(nr_masks, 1);
 550         for (i = 0; i < nr_masks; i++) {
 551                 mask->next = memblock_alloc(sizeof(*mask->next), 8);
 552                 if (!mask->next)
 553                         panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 554                               __func__, sizeof(*mask->next), 8);
 555                 mask = mask->next;
 556         }
 557 }
 558
 559 void __init topology_init_early(void)
 560 {
 561         struct sysinfo_15_1_x *info;
 562
 563         set_sched_topology(s390_topology);
 564         if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
 565                 if (MACHINE_HAS_TOPOLOGY)
 566                         topology_mode = TOPOLOGY_MODE_HW;
 567                 else
 568                         topology_mode = TOPOLOGY_MODE_SINGLE;
 569         }
 570         if (!MACHINE_HAS_TOPOLOGY)
 571                 goto out;
 572         tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 573         if (!tl_info)
 574                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 575                       __func__, PAGE_SIZE, PAGE_SIZE);
 576         info = tl_info;
 577         store_topology(info);
 578         pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
 579                 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
 580                 info->mag[4], info->mag[5], info->mnest);
 581         alloc_masks(info, &socket_info, 1);
 582         alloc_masks(info, &book_info, 2);
 583         alloc_masks(info, &drawer_info, 3);
 584 out:
 585         cpumask_set_cpu(0, &cpu_setup_mask);
 586         __arch_update_cpu_topology();
 587         __arch_update_dedicated_flag(NULL);
 588 }
 589
 590 static inline int topology_get_mode(int enabled)
 591 {
 592         if (!enabled)
 593                 return TOPOLOGY_MODE_SINGLE;
 594         return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
 595 }
 596
 597 static inline int topology_is_enabled(void)
 598 {
 599         return topology_mode != TOPOLOGY_MODE_SINGLE;
 600 }
 601
 602 static int __init topology_setup(char *str)
 603 {
 604         bool enabled;
 605         int rc;
 606
 607         rc = kstrtobool(str, &enabled);
 608         if (rc)
 609                 return rc;
 610         topology_mode = topology_get_mode(enabled);
 611         return 0;
 612 }
 613 early_param("topology", topology_setup);
 614
 615 static int topology_ctl_handler(const struct ctl_table *ctl, int write,
 616                                 void *buffer, size_t *lenp, loff_t *ppos)
 617 {
 618         int enabled = topology_is_enabled();
 619         int new_mode;
 620         int rc;
 621         struct ctl_table ctl_entry = {
 622                 .procname       = ctl->procname,
 623                 .data           = &enabled,
 624                 .maxlen         = sizeof(int),
 625                 .extra1         = SYSCTL_ZERO,
 626                 .extra2         = SYSCTL_ONE,
 627         };
 628
 629         rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 630         if (rc < 0 || !write)
 631                 return rc;
 632
 633         mutex_lock(&smp_cpu_state_mutex);
 634         new_mode = topology_get_mode(enabled);
 635         if (topology_mode != new_mode) {
 636                 topology_mode = new_mode;
 637                 topology_schedule_update();
 638         }
 639         mutex_unlock(&smp_cpu_state_mutex);
 640         topology_flush_work();
 641
 642         return rc;
 643 }
 644
 645 static int polarization_ctl_handler(const struct ctl_table *ctl, int write,
 646                                     void *buffer, size_t *lenp, loff_t *ppos)
 647 {
 648         int polarization;
 649         int rc;
 650         struct ctl_table ctl_entry = {
 651                 .procname       = ctl->procname,
 652                 .data           = &polarization,
 653                 .maxlen         = sizeof(int),
 654                 .extra1         = SYSCTL_ZERO,
 655                 .extra2         = SYSCTL_ONE,
 656         };
 657
 658         polarization = cpu_management;
 659         rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 660         if (rc < 0 || !write)
 661                 return rc;
 662         return set_polarization(polarization);
 663 }
 664
 665 static struct ctl_table topology_ctl_table[] = {
 666         {
 667                 .procname       = "topology",
 668                 .mode           = 0644,
 669                 .proc_handler   = topology_ctl_handler,
 670         },
 671         {
 672                 .procname       = "polarization",
 673                 .mode           = 0644,
 674                 .proc_handler   = polarization_ctl_handler,
 675         },
 676 };
 677
 678 static int __init topology_init(void)
 679 {
 680         struct device *dev_root;
 681         int rc = 0;
 682
 683         timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 684         if (MACHINE_HAS_TOPOLOGY)
 685                 set_topology_timer();
 686         else
 687                 topology_update_polarization_simple();
 688         if (IS_ENABLED(CONFIG_SCHED_TOPOLOGY_VERTICAL))
 689                 set_polarization(1);
 690         register_sysctl("s390", topology_ctl_table);
 691
 692         dev_root = bus_get_dev_root(&cpu_subsys);
 693         if (dev_root) {
 694                 rc = device_create_file(dev_root, &dev_attr_dispatching);
 695                 put_device(dev_root);
 696         }
 697         return rc;
 698 }
 699 device_initcall(topology_init);