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