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