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 cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
  66 {
  67         cpumask_t mask;
  68
  69         cpumask_copy(&mask, cpumask_of(cpu));
  70         switch (topology_mode) {
  71         case TOPOLOGY_MODE_HW:
  72                 while (info) {
  73                         if (cpumask_test_cpu(cpu, &info->mask)) {
  74                                 mask = info->mask;
  75                                 break;
  76                         }
  77                         info = info->next;
  78                 }
  79                 if (cpumask_empty(&mask))
  80                         cpumask_copy(&mask, cpumask_of(cpu));
  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                 cpumask_copy(&mask, cpumask_of(cpu));
  89                 break;
  90         }
  91         cpumask_and(&mask, &mask, cpu_online_mask);
  92         return mask;
  93 }
  94
  95 static cpumask_t cpu_thread_map(unsigned int cpu)
  96 {
  97         cpumask_t mask;
  98         int i;
  99
 100         cpumask_copy(&mask, cpumask_of(cpu));
 101         if (topology_mode != TOPOLOGY_MODE_HW)
 102                 return mask;
 103         cpu -= cpu % (smp_cpu_mtid + 1);
 104         for (i = 0; i <= smp_cpu_mtid; i++)
 105                 if (cpu_present(cpu + i))
 106                         cpumask_set_cpu(cpu + i, &mask);
 107         cpumask_and(&mask, &mask, cpu_online_mask);
 108         return mask;
 109 }
 110
 111 #define TOPOLOGY_CORE_BITS      64
 112
 113 static void add_cpus_to_mask(struct topology_core *tl_core,
 114                              struct mask_info *drawer,
 115                              struct mask_info *book,
 116                              struct mask_info *socket)
 117 {
 118         struct cpu_topology_s390 *topo;
 119         unsigned int core;
 120
 121         for_each_set_bit(core, &tl_core->mask, TOPOLOGY_CORE_BITS) {
 122                 unsigned int rcore;
 123                 int lcpu, i;
 124
 125                 rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
 126                 lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
 127                 if (lcpu < 0)
 128                         continue;
 129                 for (i = 0; i <= smp_cpu_mtid; i++) {
 130                         topo = &cpu_topology[lcpu + i];
 131                         topo->drawer_id = drawer->id;
 132                         topo->book_id = book->id;
 133                         topo->socket_id = socket->id;
 134                         topo->core_id = rcore;
 135                         topo->thread_id = lcpu + i;
 136                         topo->dedicated = tl_core->d;
 137                         cpumask_set_cpu(lcpu + i, &drawer->mask);
 138                         cpumask_set_cpu(lcpu + i, &book->mask);
 139                         cpumask_set_cpu(lcpu + i, &socket->mask);
 140                         smp_cpu_set_polarization(lcpu + i, tl_core->pp);
 141                 }
 142         }
 143 }
 144
 145 static void clear_masks(void)
 146 {
 147         struct mask_info *info;
 148
 149         info = &socket_info;
 150         while (info) {
 151                 cpumask_clear(&info->mask);
 152                 info = info->next;
 153         }
 154         info = &book_info;
 155         while (info) {
 156                 cpumask_clear(&info->mask);
 157                 info = info->next;
 158         }
 159         info = &drawer_info;
 160         while (info) {
 161                 cpumask_clear(&info->mask);
 162                 info = info->next;
 163         }
 164 }
 165
 166 static union topology_entry *next_tle(union topology_entry *tle)
 167 {
 168         if (!tle->nl)
 169                 return (union topology_entry *)((struct topology_core *)tle + 1);
 170         return (union topology_entry *)((struct topology_container *)tle + 1);
 171 }
 172
 173 static void tl_to_masks(struct sysinfo_15_1_x *info)
 174 {
 175         struct mask_info *socket = &socket_info;
 176         struct mask_info *book = &book_info;
 177         struct mask_info *drawer = &drawer_info;
 178         union topology_entry *tle, *end;
 179
 180         clear_masks();
 181         tle = info->tle;
 182         end = (union topology_entry *)((unsigned long)info + info->length);
 183         while (tle < end) {
 184                 switch (tle->nl) {
 185                 case 3:
 186                         drawer = drawer->next;
 187                         drawer->id = tle->container.id;
 188                         break;
 189                 case 2:
 190                         book = book->next;
 191                         book->id = tle->container.id;
 192                         break;
 193                 case 1:
 194                         socket = socket->next;
 195                         socket->id = tle->container.id;
 196                         break;
 197                 case 0:
 198                         add_cpus_to_mask(&tle->cpu, drawer, book, socket);
 199                         break;
 200                 default:
 201                         clear_masks();
 202                         return;
 203                 }
 204                 tle = next_tle(tle);
 205         }
 206 }
 207
 208 static void topology_update_polarization_simple(void)
 209 {
 210         int cpu;
 211
 212         for_each_possible_cpu(cpu)
 213                 smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
 214 }
 215
 216 static int ptf(unsigned long fc)
 217 {
 218         int rc;
 219
 220         asm volatile(
 221                 "       .insn   rre,0xb9a20000,%1,%1\n"
 222                 "       ipm     %0\n"
 223                 "       srl     %0,28\n"
 224                 : "=d" (rc)
 225                 : "d" (fc)  : "cc");
 226         return rc;
 227 }
 228
 229 int topology_set_cpu_management(int fc)
 230 {
 231         int cpu, rc;
 232
 233         if (!MACHINE_HAS_TOPOLOGY)
 234                 return -EOPNOTSUPP;
 235         if (fc)
 236                 rc = ptf(PTF_VERTICAL);
 237         else
 238                 rc = ptf(PTF_HORIZONTAL);
 239         if (rc)
 240                 return -EBUSY;
 241         for_each_possible_cpu(cpu)
 242                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 243         return rc;
 244 }
 245
 246 void update_cpu_masks(void)
 247 {
 248         struct cpu_topology_s390 *topo, *topo_package, *topo_sibling;
 249         int cpu, sibling, pkg_first, smt_first, id;
 250
 251         for_each_possible_cpu(cpu) {
 252                 topo = &cpu_topology[cpu];
 253                 topo->thread_mask = cpu_thread_map(cpu);
 254                 topo->core_mask = cpu_group_map(&socket_info, cpu);
 255                 topo->book_mask = cpu_group_map(&book_info, cpu);
 256                 topo->drawer_mask = cpu_group_map(&drawer_info, cpu);
 257                 topo->booted_cores = 0;
 258                 if (topology_mode != TOPOLOGY_MODE_HW) {
 259                         id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
 260                         topo->thread_id = cpu;
 261                         topo->core_id = cpu;
 262                         topo->socket_id = id;
 263                         topo->book_id = id;
 264                         topo->drawer_id = id;
 265                 }
 266         }
 267         for_each_online_cpu(cpu) {
 268                 topo = &cpu_topology[cpu];
 269                 pkg_first = cpumask_first(&topo->core_mask);
 270                 topo_package = &cpu_topology[pkg_first];
 271                 if (cpu == pkg_first) {
 272                         for_each_cpu(sibling, &topo->core_mask) {
 273                                 topo_sibling = &cpu_topology[sibling];
 274                                 smt_first = cpumask_first(&topo_sibling->thread_mask);
 275                                 if (sibling == smt_first)
 276                                         topo_package->booted_cores++;
 277                         }
 278                 } else {
 279                         topo->booted_cores = topo_package->booted_cores;
 280                 }
 281         }
 282 }
 283
 284 void store_topology(struct sysinfo_15_1_x *info)
 285 {
 286         stsi(info, 15, 1, topology_mnest_limit());
 287 }
 288
 289 static void __arch_update_dedicated_flag(void *arg)
 290 {
 291         if (topology_cpu_dedicated(smp_processor_id()))
 292                 set_cpu_flag(CIF_DEDICATED_CPU);
 293         else
 294                 clear_cpu_flag(CIF_DEDICATED_CPU);
 295 }
 296
 297 static int __arch_update_cpu_topology(void)
 298 {
 299         struct sysinfo_15_1_x *info = tl_info;
 300         int rc = 0;
 301
 302         mutex_lock(&smp_cpu_state_mutex);
 303         if (MACHINE_HAS_TOPOLOGY) {
 304                 rc = 1;
 305                 store_topology(info);
 306                 tl_to_masks(info);
 307         }
 308         update_cpu_masks();
 309         if (!MACHINE_HAS_TOPOLOGY)
 310                 topology_update_polarization_simple();
 311         mutex_unlock(&smp_cpu_state_mutex);
 312         return rc;
 313 }
 314
 315 int arch_update_cpu_topology(void)
 316 {
 317         struct device *dev;
 318         int cpu, rc;
 319
 320         rc = __arch_update_cpu_topology();
 321         on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
 322         for_each_online_cpu(cpu) {
 323                 dev = get_cpu_device(cpu);
 324                 if (dev)
 325                         kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 326         }
 327         return rc;
 328 }
 329
 330 static void topology_work_fn(struct work_struct *work)
 331 {
 332         rebuild_sched_domains();
 333 }
 334
 335 void topology_schedule_update(void)
 336 {
 337         schedule_work(&topology_work);
 338 }
 339
 340 static void topology_flush_work(void)
 341 {
 342         flush_work(&topology_work);
 343 }
 344
 345 static void topology_timer_fn(struct timer_list *unused)
 346 {
 347         if (ptf(PTF_CHECK))
 348                 topology_schedule_update();
 349         set_topology_timer();
 350 }
 351
 352 static struct timer_list topology_timer;
 353
 354 static atomic_t topology_poll = ATOMIC_INIT(0);
 355
 356 static void set_topology_timer(void)
 357 {
 358         if (atomic_add_unless(&topology_poll, -1, 0))
 359                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(100));
 360         else
 361                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(60 * MSEC_PER_SEC));
 362 }
 363
 364 void topology_expect_change(void)
 365 {
 366         if (!MACHINE_HAS_TOPOLOGY)
 367                 return;
 368         /* This is racy, but it doesn't matter since it is just a heuristic.
 369          * Worst case is that we poll in a higher frequency for a bit longer.
 370          */
 371         if (atomic_read(&topology_poll) > 60)
 372                 return;
 373         atomic_add(60, &topology_poll);
 374         set_topology_timer();
 375 }
 376
 377 static int cpu_management;
 378
 379 static ssize_t dispatching_show(struct device *dev,
 380                                 struct device_attribute *attr,
 381                                 char *buf)
 382 {
 383         ssize_t count;
 384
 385         mutex_lock(&smp_cpu_state_mutex);
 386         count = sprintf(buf, "%d\n", cpu_management);
 387         mutex_unlock(&smp_cpu_state_mutex);
 388         return count;
 389 }
 390
 391 static ssize_t dispatching_store(struct device *dev,
 392                                  struct device_attribute *attr,
 393                                  const char *buf,
 394                                  size_t count)
 395 {
 396         int val, rc;
 397         char delim;
 398
 399         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 400                 return -EINVAL;
 401         if (val != 0 && val != 1)
 402                 return -EINVAL;
 403         rc = 0;
 404         get_online_cpus();
 405         mutex_lock(&smp_cpu_state_mutex);
 406         if (cpu_management == val)
 407                 goto out;
 408         rc = topology_set_cpu_management(val);
 409         if (rc)
 410                 goto out;
 411         cpu_management = val;
 412         topology_expect_change();
 413 out:
 414         mutex_unlock(&smp_cpu_state_mutex);
 415         put_online_cpus();
 416         return rc ? rc : count;
 417 }
 418 static DEVICE_ATTR_RW(dispatching);
 419
 420 static ssize_t cpu_polarization_show(struct device *dev,
 421                                      struct device_attribute *attr, char *buf)
 422 {
 423         int cpu = dev->id;
 424         ssize_t count;
 425
 426         mutex_lock(&smp_cpu_state_mutex);
 427         switch (smp_cpu_get_polarization(cpu)) {
 428         case POLARIZATION_HRZ:
 429                 count = sprintf(buf, "horizontal\n");
 430                 break;
 431         case POLARIZATION_VL:
 432                 count = sprintf(buf, "vertical:low\n");
 433                 break;
 434         case POLARIZATION_VM:
 435                 count = sprintf(buf, "vertical:medium\n");
 436                 break;
 437         case POLARIZATION_VH:
 438                 count = sprintf(buf, "vertical:high\n");
 439                 break;
 440         default:
 441                 count = sprintf(buf, "unknown\n");
 442                 break;
 443         }
 444         mutex_unlock(&smp_cpu_state_mutex);
 445         return count;
 446 }
 447 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 448
 449 static struct attribute *topology_cpu_attrs[] = {
 450         &dev_attr_polarization.attr,
 451         NULL,
 452 };
 453
 454 static struct attribute_group topology_cpu_attr_group = {
 455         .attrs = topology_cpu_attrs,
 456 };
 457
 458 static ssize_t cpu_dedicated_show(struct device *dev,
 459                                   struct device_attribute *attr, char *buf)
 460 {
 461         int cpu = dev->id;
 462         ssize_t count;
 463
 464         mutex_lock(&smp_cpu_state_mutex);
 465         count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
 466         mutex_unlock(&smp_cpu_state_mutex);
 467         return count;
 468 }
 469 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 470
 471 static struct attribute *topology_extra_cpu_attrs[] = {
 472         &dev_attr_dedicated.attr,
 473         NULL,
 474 };
 475
 476 static struct attribute_group topology_extra_cpu_attr_group = {
 477         .attrs = topology_extra_cpu_attrs,
 478 };
 479
 480 int topology_cpu_init(struct cpu *cpu)
 481 {
 482         int rc;
 483
 484         rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 485         if (rc || !MACHINE_HAS_TOPOLOGY)
 486                 return rc;
 487         rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
 488         if (rc)
 489                 sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 490         return rc;
 491 }
 492
 493 static const struct cpumask *cpu_thread_mask(int cpu)
 494 {
 495         return &cpu_topology[cpu].thread_mask;
 496 }
 497
 498
 499 const struct cpumask *cpu_coregroup_mask(int cpu)
 500 {
 501         return &cpu_topology[cpu].core_mask;
 502 }
 503
 504 static const struct cpumask *cpu_book_mask(int cpu)
 505 {
 506         return &cpu_topology[cpu].book_mask;
 507 }
 508
 509 static const struct cpumask *cpu_drawer_mask(int cpu)
 510 {
 511         return &cpu_topology[cpu].drawer_mask;
 512 }
 513
 514 static struct sched_domain_topology_level s390_topology[] = {
 515         { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
 516         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 517         { cpu_book_mask, SD_INIT_NAME(BOOK) },
 518         { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
 519         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 520         { NULL, },
 521 };
 522
 523 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 524                                struct mask_info *mask, int offset)
 525 {
 526         int i, nr_masks;
 527
 528         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 529         for (i = 0; i < info->mnest - offset; i++)
 530                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 531         nr_masks = max(nr_masks, 1);
 532         for (i = 0; i < nr_masks; i++) {
 533                 mask->next = memblock_alloc(sizeof(*mask->next), 8);
 534                 if (!mask->next)
 535                         panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 536                               __func__, sizeof(*mask->next), 8);
 537                 mask = mask->next;
 538         }
 539 }
 540
 541 void __init topology_init_early(void)
 542 {
 543         struct sysinfo_15_1_x *info;
 544
 545         set_sched_topology(s390_topology);
 546         if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
 547                 if (MACHINE_HAS_TOPOLOGY)
 548                         topology_mode = TOPOLOGY_MODE_HW;
 549                 else
 550                         topology_mode = TOPOLOGY_MODE_SINGLE;
 551         }
 552         if (!MACHINE_HAS_TOPOLOGY)
 553                 goto out;
 554         tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 555         if (!tl_info)
 556                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 557                       __func__, PAGE_SIZE, PAGE_SIZE);
 558         info = tl_info;
 559         store_topology(info);
 560         pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
 561                 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
 562                 info->mag[4], info->mag[5], info->mnest);
 563         alloc_masks(info, &socket_info, 1);
 564         alloc_masks(info, &book_info, 2);
 565         alloc_masks(info, &drawer_info, 3);
 566 out:
 567         __arch_update_cpu_topology();
 568         __arch_update_dedicated_flag(NULL);
 569 }
 570
 571 static inline int topology_get_mode(int enabled)
 572 {
 573         if (!enabled)
 574                 return TOPOLOGY_MODE_SINGLE;
 575         return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
 576 }
 577
 578 static inline int topology_is_enabled(void)
 579 {
 580         return topology_mode != TOPOLOGY_MODE_SINGLE;
 581 }
 582
 583 static int __init topology_setup(char *str)
 584 {
 585         bool enabled;
 586         int rc;
 587
 588         rc = kstrtobool(str, &enabled);
 589         if (rc)
 590                 return rc;
 591         topology_mode = topology_get_mode(enabled);
 592         return 0;
 593 }
 594 early_param("topology", topology_setup);
 595
 596 static int topology_ctl_handler(struct ctl_table *ctl, int write,
 597                                 void *buffer, size_t *lenp, loff_t *ppos)
 598 {
 599         int enabled = topology_is_enabled();
 600         int new_mode;
 601         int rc;
 602         struct ctl_table ctl_entry = {
 603                 .procname       = ctl->procname,
 604                 .data           = &enabled,
 605                 .maxlen         = sizeof(int),
 606                 .extra1         = SYSCTL_ZERO,
 607                 .extra2         = SYSCTL_ONE,
 608         };
 609
 610         rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 611         if (rc < 0 || !write)
 612                 return rc;
 613
 614         mutex_lock(&smp_cpu_state_mutex);
 615         new_mode = topology_get_mode(enabled);
 616         if (topology_mode != new_mode) {
 617                 topology_mode = new_mode;
 618                 topology_schedule_update();
 619         }
 620         mutex_unlock(&smp_cpu_state_mutex);
 621         topology_flush_work();
 622
 623         return rc;
 624 }
 625
 626 static struct ctl_table topology_ctl_table[] = {
 627         {
 628                 .procname       = "topology",
 629                 .mode           = 0644,
 630                 .proc_handler   = topology_ctl_handler,
 631         },
 632         { },
 633 };
 634
 635 static struct ctl_table topology_dir_table[] = {
 636         {
 637                 .procname       = "s390",
 638                 .maxlen         = 0,
 639                 .mode           = 0555,
 640                 .child          = topology_ctl_table,
 641         },
 642         { },
 643 };
 644
 645 static int __init topology_init(void)
 646 {
 647         timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 648         if (MACHINE_HAS_TOPOLOGY)
 649                 set_topology_timer();
 650         else
 651                 topology_update_polarization_simple();
 652         register_sysctl_table(topology_dir_table);
 653         return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 654 }
 655 device_initcall(topology_init);