arch/s390/kernel/topology.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Copyright IBM Corp. 2007, 2011
   4  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   5  */
   6
   7 #define KMSG_COMPONENT "cpu"
   8 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
   9
  10 #include <linux/workqueue.h>
  11 #include <linux/memblock.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/sysctl.h>
  14 #include <linux/cpuset.h>
  15 #include <linux/device.h>
  16 #include <linux/export.h>
  17 #include <linux/kernel.h>
  18 #include <linux/sched.h>
  19 #include <linux/sched/topology.h>
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <linux/cpu.h>
  24 #include <linux/smp.h>
  25 #include <linux/mm.h>
  26 #include <linux/nodemask.h>
  27 #include <linux/node.h>
  28 #include <asm/sysinfo.h>
  29
  30 #define PTF_HORIZONTAL  (0UL)
  31 #define PTF_VERTICAL    (1UL)
  32 #define PTF_CHECK       (2UL)
  33
  34 enum {
  35         TOPOLOGY_MODE_HW,
  36         TOPOLOGY_MODE_SINGLE,
  37         TOPOLOGY_MODE_PACKAGE,
  38         TOPOLOGY_MODE_UNINITIALIZED
  39 };
  40
  41 struct mask_info {
  42         struct mask_info *next;
  43         unsigned char id;
  44         cpumask_t mask;
  45 };
  46
  47 static int topology_mode = TOPOLOGY_MODE_UNINITIALIZED;
  48 static void set_topology_timer(void);
  49 static void topology_work_fn(struct work_struct *work);
  50 static struct sysinfo_15_1_x *tl_info;
  51
  52 static DECLARE_WORK(topology_work, topology_work_fn);
  53
  54 /*
  55  * Socket/Book linked lists and cpu_topology updates are
  56  * protected by "sched_domains_mutex".
  57  */
  58 static struct mask_info socket_info;
  59 static struct mask_info book_info;
  60 static struct mask_info drawer_info;
  61
  62 struct cpu_topology_s390 cpu_topology[NR_CPUS];
  63 EXPORT_SYMBOL_GPL(cpu_topology);
  64
  65 static void cpu_group_map(cpumask_t *dst, struct mask_info *info, unsigned int cpu)
  66 {
  67         static cpumask_t mask;
  68
  69         cpumask_clear(&mask);
  70         if (!cpu_online(cpu))
  71                 goto out;
  72         cpumask_set_cpu(cpu, &mask);
  73         switch (topology_mode) {
  74         case TOPOLOGY_MODE_HW:
  75                 while (info) {
  76                         if (cpumask_test_cpu(cpu, &info->mask)) {
  77                                 cpumask_copy(&mask, &info->mask);
  78                                 break;
  79                         }
  80                         info = info->next;
  81                 }
  82                 break;
  83         case TOPOLOGY_MODE_PACKAGE:
  84                 cpumask_copy(&mask, cpu_present_mask);
  85                 break;
  86         default:
  87                 fallthrough;
  88         case TOPOLOGY_MODE_SINGLE:
  89                 break;
  90         }
  91         cpumask_and(&mask, &mask, cpu_online_mask);
  92 out:
  93         cpumask_copy(dst, &mask);
  94 }
  95
  96 static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
  97 {
  98         static cpumask_t mask;
  99         int i;
 100
 101         cpumask_clear(&mask);
 102         if (!cpu_online(cpu))
 103                 goto out;
 104         cpumask_set_cpu(cpu, &mask);
 105         if (topology_mode != TOPOLOGY_MODE_HW)
 106                 goto out;
 107         cpu -= cpu % (smp_cpu_mtid + 1);
 108         for (i = 0; i <= smp_cpu_mtid; i++)
 109                 if (cpu_present(cpu + i))
 110                         cpumask_set_cpu(cpu + i, &mask);
 111         cpumask_and(&mask, &mask, cpu_online_mask);
 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 rcore;
 128                 int lcpu, i;
 129
 130                 rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
 131                 lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
 132                 if (lcpu < 0)
 133                         continue;
 134                 for (i = 0; i <= smp_cpu_mtid; i++) {
 135                         topo = &cpu_topology[lcpu + i];
 136                         topo->drawer_id = drawer->id;
 137                         topo->book_id = book->id;
 138                         topo->socket_id = socket->id;
 139                         topo->core_id = rcore;
 140                         topo->thread_id = lcpu + i;
 141                         topo->dedicated = tl_core->d;
 142                         cpumask_set_cpu(lcpu + i, &drawer->mask);
 143                         cpumask_set_cpu(lcpu + i, &book->mask);
 144                         cpumask_set_cpu(lcpu + i, &socket->mask);
 145                         smp_cpu_set_polarization(lcpu + i, tl_core->pp);
 146                 }
 147         }
 148 }
 149
 150 static void clear_masks(void)
 151 {
 152         struct mask_info *info;
 153
 154         info = &socket_info;
 155         while (info) {
 156                 cpumask_clear(&info->mask);
 157                 info = info->next;
 158         }
 159         info = &book_info;
 160         while (info) {
 161                 cpumask_clear(&info->mask);
 162                 info = info->next;
 163         }
 164         info = &drawer_info;
 165         while (info) {
 166                 cpumask_clear(&info->mask);
 167                 info = info->next;
 168         }
 169 }
 170
 171 static union topology_entry *next_tle(union topology_entry *tle)
 172 {
 173         if (!tle->nl)
 174                 return (union topology_entry *)((struct topology_core *)tle + 1);
 175         return (union topology_entry *)((struct topology_container *)tle + 1);
 176 }
 177
 178 static void tl_to_masks(struct sysinfo_15_1_x *info)
 179 {
 180         struct mask_info *socket = &socket_info;
 181         struct mask_info *book = &book_info;
 182         struct mask_info *drawer = &drawer_info;
 183         union topology_entry *tle, *end;
 184
 185         clear_masks();
 186         tle = info->tle;
 187         end = (union topology_entry *)((unsigned long)info + info->length);
 188         while (tle < end) {
 189                 switch (tle->nl) {
 190                 case 3:
 191                         drawer = drawer->next;
 192                         drawer->id = tle->container.id;
 193                         break;
 194                 case 2:
 195                         book = book->next;
 196                         book->id = tle->container.id;
 197                         break;
 198                 case 1:
 199                         socket = socket->next;
 200                         socket->id = tle->container.id;
 201                         break;
 202                 case 0:
 203                         add_cpus_to_mask(&tle->cpu, drawer, book, socket);
 204                         break;
 205                 default:
 206                         clear_masks();
 207                         return;
 208                 }
 209                 tle = next_tle(tle);
 210         }
 211 }
 212
 213 static void topology_update_polarization_simple(void)
 214 {
 215         int cpu;
 216
 217         for_each_possible_cpu(cpu)
 218                 smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
 219 }
 220
 221 static int ptf(unsigned long fc)
 222 {
 223         int rc;
 224
 225         asm volatile(
 226                 "       .insn   rre,0xb9a20000,%1,%1\n"
 227                 "       ipm     %0\n"
 228                 "       srl     %0,28\n"
 229                 : "=d" (rc)
 230                 : "d" (fc)  : "cc");
 231         return rc;
 232 }
 233
 234 int topology_set_cpu_management(int fc)
 235 {
 236         int cpu, rc;
 237
 238         if (!MACHINE_HAS_TOPOLOGY)
 239                 return -EOPNOTSUPP;
 240         if (fc)
 241                 rc = ptf(PTF_VERTICAL);
 242         else
 243                 rc = ptf(PTF_HORIZONTAL);
 244         if (rc)
 245                 return -EBUSY;
 246         for_each_possible_cpu(cpu)
 247                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 248         return rc;
 249 }
 250
 251 void update_cpu_masks(void)
 252 {
 253         struct cpu_topology_s390 *topo, *topo_package, *topo_sibling;
 254         int cpu, sibling, pkg_first, smt_first, id;
 255
 256         for_each_possible_cpu(cpu) {
 257                 topo = &cpu_topology[cpu];
 258                 cpu_thread_map(&topo->thread_mask, cpu);
 259                 cpu_group_map(&topo->core_mask, &socket_info, cpu);
 260                 cpu_group_map(&topo->book_mask, &book_info, cpu);
 261                 cpu_group_map(&topo->drawer_mask, &drawer_info, cpu);
 262                 topo->booted_cores = 0;
 263                 if (topology_mode != TOPOLOGY_MODE_HW) {
 264                         id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
 265                         topo->thread_id = cpu;
 266                         topo->core_id = cpu;
 267                         topo->socket_id = id;
 268                         topo->book_id = id;
 269                         topo->drawer_id = id;
 270                 }
 271         }
 272         for_each_online_cpu(cpu) {
 273                 topo = &cpu_topology[cpu];
 274                 pkg_first = cpumask_first(&topo->core_mask);
 275                 topo_package = &cpu_topology[pkg_first];
 276                 if (cpu == pkg_first) {
 277                         for_each_cpu(sibling, &topo->core_mask) {
 278                                 topo_sibling = &cpu_topology[sibling];
 279                                 smt_first = cpumask_first(&topo_sibling->thread_mask);
 280                                 if (sibling == smt_first)
 281                                         topo_package->booted_cores++;
 282                         }
 283                 } else {
 284                         topo->booted_cores = topo_package->booted_cores;
 285                 }
 286         }
 287 }
 288
 289 void store_topology(struct sysinfo_15_1_x *info)
 290 {
 291         stsi(info, 15, 1, topology_mnest_limit());
 292 }
 293
 294 static void __arch_update_dedicated_flag(void *arg)
 295 {
 296         if (topology_cpu_dedicated(smp_processor_id()))
 297                 set_cpu_flag(CIF_DEDICATED_CPU);
 298         else
 299                 clear_cpu_flag(CIF_DEDICATED_CPU);
 300 }
 301
 302 static int __arch_update_cpu_topology(void)
 303 {
 304         struct sysinfo_15_1_x *info = tl_info;
 305         int rc = 0;
 306
 307         mutex_lock(&smp_cpu_state_mutex);
 308         if (MACHINE_HAS_TOPOLOGY) {
 309                 rc = 1;
 310                 store_topology(info);
 311                 tl_to_masks(info);
 312         }
 313         update_cpu_masks();
 314         if (!MACHINE_HAS_TOPOLOGY)
 315                 topology_update_polarization_simple();
 316         mutex_unlock(&smp_cpu_state_mutex);
 317         return rc;
 318 }
 319
 320 int arch_update_cpu_topology(void)
 321 {
 322         struct device *dev;
 323         int cpu, rc;
 324
 325         rc = __arch_update_cpu_topology();
 326         on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
 327         for_each_online_cpu(cpu) {
 328                 dev = get_cpu_device(cpu);
 329                 if (dev)
 330                         kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 331         }
 332         return rc;
 333 }
 334
 335 static void topology_work_fn(struct work_struct *work)
 336 {
 337         rebuild_sched_domains();
 338 }
 339
 340 void topology_schedule_update(void)
 341 {
 342         schedule_work(&topology_work);
 343 }
 344
 345 static void topology_flush_work(void)
 346 {
 347         flush_work(&topology_work);
 348 }
 349
 350 static void topology_timer_fn(struct timer_list *unused)
 351 {
 352         if (ptf(PTF_CHECK))
 353                 topology_schedule_update();
 354         set_topology_timer();
 355 }
 356
 357 static struct timer_list topology_timer;
 358
 359 static atomic_t topology_poll = ATOMIC_INIT(0);
 360
 361 static void set_topology_timer(void)
 362 {
 363         if (atomic_add_unless(&topology_poll, -1, 0))
 364                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(100));
 365         else
 366                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(60 * MSEC_PER_SEC));
 367 }
 368
 369 void topology_expect_change(void)
 370 {
 371         if (!MACHINE_HAS_TOPOLOGY)
 372                 return;
 373         /* This is racy, but it doesn't matter since it is just a heuristic.
 374          * Worst case is that we poll in a higher frequency for a bit longer.
 375          */
 376         if (atomic_read(&topology_poll) > 60)
 377                 return;
 378         atomic_add(60, &topology_poll);
 379         set_topology_timer();
 380 }
 381
 382 static int cpu_management;
 383
 384 static ssize_t dispatching_show(struct device *dev,
 385                                 struct device_attribute *attr,
 386                                 char *buf)
 387 {
 388         ssize_t count;
 389
 390         mutex_lock(&smp_cpu_state_mutex);
 391         count = sprintf(buf, "%d\n", cpu_management);
 392         mutex_unlock(&smp_cpu_state_mutex);
 393         return count;
 394 }
 395
 396 static ssize_t dispatching_store(struct device *dev,
 397                                  struct device_attribute *attr,
 398                                  const char *buf,
 399                                  size_t count)
 400 {
 401         int val, rc;
 402         char delim;
 403
 404         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 405                 return -EINVAL;
 406         if (val != 0 && val != 1)
 407                 return -EINVAL;
 408         rc = 0;
 409         cpus_read_lock();
 410         mutex_lock(&smp_cpu_state_mutex);
 411         if (cpu_management == val)
 412                 goto out;
 413         rc = topology_set_cpu_management(val);
 414         if (rc)
 415                 goto out;
 416         cpu_management = val;
 417         topology_expect_change();
 418 out:
 419         mutex_unlock(&smp_cpu_state_mutex);
 420         cpus_read_unlock();
 421         return rc ? rc : count;
 422 }
 423 static DEVICE_ATTR_RW(dispatching);
 424
 425 static ssize_t cpu_polarization_show(struct device *dev,
 426                                      struct device_attribute *attr, char *buf)
 427 {
 428         int cpu = dev->id;
 429         ssize_t count;
 430
 431         mutex_lock(&smp_cpu_state_mutex);
 432         switch (smp_cpu_get_polarization(cpu)) {
 433         case POLARIZATION_HRZ:
 434                 count = sprintf(buf, "horizontal\n");
 435                 break;
 436         case POLARIZATION_VL:
 437                 count = sprintf(buf, "vertical:low\n");
 438                 break;
 439         case POLARIZATION_VM:
 440                 count = sprintf(buf, "vertical:medium\n");
 441                 break;
 442         case POLARIZATION_VH:
 443                 count = sprintf(buf, "vertical:high\n");
 444                 break;
 445         default:
 446                 count = sprintf(buf, "unknown\n");
 447                 break;
 448         }
 449         mutex_unlock(&smp_cpu_state_mutex);
 450         return count;
 451 }
 452 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 453
 454 static struct attribute *topology_cpu_attrs[] = {
 455         &dev_attr_polarization.attr,
 456         NULL,
 457 };
 458
 459 static struct attribute_group topology_cpu_attr_group = {
 460         .attrs = topology_cpu_attrs,
 461 };
 462
 463 static ssize_t cpu_dedicated_show(struct device *dev,
 464                                   struct device_attribute *attr, char *buf)
 465 {
 466         int cpu = dev->id;
 467         ssize_t count;
 468
 469         mutex_lock(&smp_cpu_state_mutex);
 470         count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
 471         mutex_unlock(&smp_cpu_state_mutex);
 472         return count;
 473 }
 474 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 475
 476 static struct attribute *topology_extra_cpu_attrs[] = {
 477         &dev_attr_dedicated.attr,
 478         NULL,
 479 };
 480
 481 static struct attribute_group topology_extra_cpu_attr_group = {
 482         .attrs = topology_extra_cpu_attrs,
 483 };
 484
 485 int topology_cpu_init(struct cpu *cpu)
 486 {
 487         int rc;
 488
 489         rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 490         if (rc || !MACHINE_HAS_TOPOLOGY)
 491                 return rc;
 492         rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
 493         if (rc)
 494                 sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 495         return rc;
 496 }
 497
 498 static const struct cpumask *cpu_thread_mask(int cpu)
 499 {
 500         return &cpu_topology[cpu].thread_mask;
 501 }
 502
 503
 504 const struct cpumask *cpu_coregroup_mask(int cpu)
 505 {
 506         return &cpu_topology[cpu].core_mask;
 507 }
 508
 509 static const struct cpumask *cpu_book_mask(int cpu)
 510 {
 511         return &cpu_topology[cpu].book_mask;
 512 }
 513
 514 static const struct cpumask *cpu_drawer_mask(int cpu)
 515 {
 516         return &cpu_topology[cpu].drawer_mask;
 517 }
 518
 519 static struct sched_domain_topology_level s390_topology[] = {
 520         { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
 521         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 522         { cpu_book_mask, SD_INIT_NAME(BOOK) },
 523         { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
 524         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 525         { NULL, },
 526 };
 527
 528 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 529                                struct mask_info *mask, int offset)
 530 {
 531         int i, nr_masks;
 532
 533         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 534         for (i = 0; i < info->mnest - offset; i++)
 535                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 536         nr_masks = max(nr_masks, 1);
 537         for (i = 0; i < nr_masks; i++) {
 538                 mask->next = memblock_alloc(sizeof(*mask->next), 8);
 539                 if (!mask->next)
 540                         panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 541                               __func__, sizeof(*mask->next), 8);
 542                 mask = mask->next;
 543         }
 544 }
 545
 546 void __init topology_init_early(void)
 547 {
 548         struct sysinfo_15_1_x *info;
 549
 550         set_sched_topology(s390_topology);
 551         if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
 552                 if (MACHINE_HAS_TOPOLOGY)
 553                         topology_mode = TOPOLOGY_MODE_HW;
 554                 else
 555                         topology_mode = TOPOLOGY_MODE_SINGLE;
 556         }
 557         if (!MACHINE_HAS_TOPOLOGY)
 558                 goto out;
 559         tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 560         if (!tl_info)
 561                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 562                       __func__, PAGE_SIZE, PAGE_SIZE);
 563         info = tl_info;
 564         store_topology(info);
 565         pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
 566                 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
 567                 info->mag[4], info->mag[5], info->mnest);
 568         alloc_masks(info, &socket_info, 1);
 569         alloc_masks(info, &book_info, 2);
 570         alloc_masks(info, &drawer_info, 3);
 571 out:
 572         __arch_update_cpu_topology();
 573         __arch_update_dedicated_flag(NULL);
 574 }
 575
 576 static inline int topology_get_mode(int enabled)
 577 {
 578         if (!enabled)
 579                 return TOPOLOGY_MODE_SINGLE;
 580         return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
 581 }
 582
 583 static inline int topology_is_enabled(void)
 584 {
 585         return topology_mode != TOPOLOGY_MODE_SINGLE;
 586 }
 587
 588 static int __init topology_setup(char *str)
 589 {
 590         bool enabled;
 591         int rc;
 592
 593         rc = kstrtobool(str, &enabled);
 594         if (rc)
 595                 return rc;
 596         topology_mode = topology_get_mode(enabled);
 597         return 0;
 598 }
 599 early_param("topology", topology_setup);
 600
 601 static int topology_ctl_handler(struct ctl_table *ctl, int write,
 602                                 void *buffer, size_t *lenp, loff_t *ppos)
 603 {
 604         int enabled = topology_is_enabled();
 605         int new_mode;
 606         int rc;
 607         struct ctl_table ctl_entry = {
 608                 .procname       = ctl->procname,
 609                 .data           = &enabled,
 610                 .maxlen         = sizeof(int),
 611                 .extra1         = SYSCTL_ZERO,
 612                 .extra2         = SYSCTL_ONE,
 613         };
 614
 615         rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 616         if (rc < 0 || !write)
 617                 return rc;
 618
 619         mutex_lock(&smp_cpu_state_mutex);
 620         new_mode = topology_get_mode(enabled);
 621         if (topology_mode != new_mode) {
 622                 topology_mode = new_mode;
 623                 topology_schedule_update();
 624         }
 625         mutex_unlock(&smp_cpu_state_mutex);
 626         topology_flush_work();
 627
 628         return rc;
 629 }
 630
 631 static struct ctl_table topology_ctl_table[] = {
 632         {
 633                 .procname       = "topology",
 634                 .mode           = 0644,
 635                 .proc_handler   = topology_ctl_handler,
 636         },
 637         { },
 638 };
 639
 640 static struct ctl_table topology_dir_table[] = {
 641         {
 642                 .procname       = "s390",
 643                 .maxlen         = 0,
 644                 .mode           = 0555,
 645                 .child          = topology_ctl_table,
 646         },
 647         { },
 648 };
 649
 650 static int __init topology_init(void)
 651 {
 652         timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 653         if (MACHINE_HAS_TOPOLOGY)
 654                 set_topology_timer();
 655         else
 656                 topology_update_polarization_simple();
 657         register_sysctl_table(topology_dir_table);
 658         return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 659 }
 660 device_initcall(topology_init);