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_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                                 cpumask_copy(&mask, &info->mask);
  75                                 break;
  76                         }
  77                         info = info->next;
  78                 }
  79                 break;
  80         case TOPOLOGY_MODE_PACKAGE:
  81                 cpumask_copy(&mask, cpu_present_mask);
  82                 break;
  83         default:
  84                 fallthrough;
  85         case TOPOLOGY_MODE_SINGLE:
  86                 cpumask_copy(&mask, cpumask_of(cpu));
  87                 break;
  88         }
  89         cpumask_and(&mask, &mask, cpu_online_mask);
  90         cpumask_copy(dst, &mask);
  91 }
  92
  93 static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
  94 {
  95         static cpumask_t mask;
  96         int i;
  97
  98         cpumask_copy(&mask, cpumask_of(cpu));
  99         if (topology_mode != TOPOLOGY_MODE_HW)
 100                 goto out;
 101         cpu -= cpu % (smp_cpu_mtid + 1);
 102         for (i = 0; i <= smp_cpu_mtid; i++)
 103                 if (cpu_present(cpu + i))
 104                         cpumask_set_cpu(cpu + i, &mask);
 105         cpumask_and(&mask, &mask, cpu_online_mask);
 106 out:
 107         cpumask_copy(dst, &mask);
 108 }
 109
 110 #define TOPOLOGY_CORE_BITS      64
 111
 112 static void add_cpus_to_mask(struct topology_core *tl_core,
 113                              struct mask_info *drawer,
 114                              struct mask_info *book,
 115                              struct mask_info *socket)
 116 {
 117         struct cpu_topology_s390 *topo;
 118         unsigned int core;
 119
 120         for_each_set_bit(core, &tl_core->mask, TOPOLOGY_CORE_BITS) {
 121                 unsigned int rcore;
 122                 int lcpu, i;
 123
 124                 rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
 125                 lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
 126                 if (lcpu < 0)
 127                         continue;
 128                 for (i = 0; i <= smp_cpu_mtid; i++) {
 129                         topo = &cpu_topology[lcpu + i];
 130                         topo->drawer_id = drawer->id;
 131                         topo->book_id = book->id;
 132                         topo->socket_id = socket->id;
 133                         topo->core_id = rcore;
 134                         topo->thread_id = lcpu + i;
 135                         topo->dedicated = tl_core->d;
 136                         cpumask_set_cpu(lcpu + i, &drawer->mask);
 137                         cpumask_set_cpu(lcpu + i, &book->mask);
 138                         cpumask_set_cpu(lcpu + i, &socket->mask);
 139                         smp_cpu_set_polarization(lcpu + i, tl_core->pp);
 140                 }
 141         }
 142 }
 143
 144 static void clear_masks(void)
 145 {
 146         struct mask_info *info;
 147
 148         info = &socket_info;
 149         while (info) {
 150                 cpumask_clear(&info->mask);
 151                 info = info->next;
 152         }
 153         info = &book_info;
 154         while (info) {
 155                 cpumask_clear(&info->mask);
 156                 info = info->next;
 157         }
 158         info = &drawer_info;
 159         while (info) {
 160                 cpumask_clear(&info->mask);
 161                 info = info->next;
 162         }
 163 }
 164
 165 static union topology_entry *next_tle(union topology_entry *tle)
 166 {
 167         if (!tle->nl)
 168                 return (union topology_entry *)((struct topology_core *)tle + 1);
 169         return (union topology_entry *)((struct topology_container *)tle + 1);
 170 }
 171
 172 static void tl_to_masks(struct sysinfo_15_1_x *info)
 173 {
 174         struct mask_info *socket = &socket_info;
 175         struct mask_info *book = &book_info;
 176         struct mask_info *drawer = &drawer_info;
 177         union topology_entry *tle, *end;
 178
 179         clear_masks();
 180         tle = info->tle;
 181         end = (union topology_entry *)((unsigned long)info + info->length);
 182         while (tle < end) {
 183                 switch (tle->nl) {
 184                 case 3:
 185                         drawer = drawer->next;
 186                         drawer->id = tle->container.id;
 187                         break;
 188                 case 2:
 189                         book = book->next;
 190                         book->id = tle->container.id;
 191                         break;
 192                 case 1:
 193                         socket = socket->next;
 194                         socket->id = tle->container.id;
 195                         break;
 196                 case 0:
 197                         add_cpus_to_mask(&tle->cpu, drawer, book, socket);
 198                         break;
 199                 default:
 200                         clear_masks();
 201                         return;
 202                 }
 203                 tle = next_tle(tle);
 204         }
 205 }
 206
 207 static void topology_update_polarization_simple(void)
 208 {
 209         int cpu;
 210
 211         for_each_possible_cpu(cpu)
 212                 smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
 213 }
 214
 215 static int ptf(unsigned long fc)
 216 {
 217         int rc;
 218
 219         asm volatile(
 220                 "       .insn   rre,0xb9a20000,%1,%1\n"
 221                 "       ipm     %0\n"
 222                 "       srl     %0,28\n"
 223                 : "=d" (rc)
 224                 : "d" (fc)  : "cc");
 225         return rc;
 226 }
 227
 228 int topology_set_cpu_management(int fc)
 229 {
 230         int cpu, rc;
 231
 232         if (!MACHINE_HAS_TOPOLOGY)
 233                 return -EOPNOTSUPP;
 234         if (fc)
 235                 rc = ptf(PTF_VERTICAL);
 236         else
 237                 rc = ptf(PTF_HORIZONTAL);
 238         if (rc)
 239                 return -EBUSY;
 240         for_each_possible_cpu(cpu)
 241                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 242         return rc;
 243 }
 244
 245 void update_cpu_masks(void)
 246 {
 247         struct cpu_topology_s390 *topo, *topo_package, *topo_sibling;
 248         int cpu, sibling, pkg_first, smt_first, id;
 249
 250         for_each_possible_cpu(cpu) {
 251                 topo = &cpu_topology[cpu];
 252                 cpu_thread_map(&topo->thread_mask, cpu);
 253                 cpu_group_map(&topo->core_mask, &socket_info, cpu);
 254                 cpu_group_map(&topo->book_mask, &book_info, cpu);
 255                 cpu_group_map(&topo->drawer_mask, &drawer_info, cpu);
 256                 topo->booted_cores = 0;
 257                 if (topology_mode != TOPOLOGY_MODE_HW) {
 258                         id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
 259                         topo->thread_id = cpu;
 260                         topo->core_id = cpu;
 261                         topo->socket_id = id;
 262                         topo->book_id = id;
 263                         topo->drawer_id = id;
 264                 }
 265         }
 266         for_each_online_cpu(cpu) {
 267                 topo = &cpu_topology[cpu];
 268                 pkg_first = cpumask_first(&topo->core_mask);
 269                 topo_package = &cpu_topology[pkg_first];
 270                 if (cpu == pkg_first) {
 271                         for_each_cpu(sibling, &topo->core_mask) {
 272                                 topo_sibling = &cpu_topology[sibling];
 273                                 smt_first = cpumask_first(&topo_sibling->thread_mask);
 274                                 if (sibling == smt_first)
 275                                         topo_package->booted_cores++;
 276                         }
 277                 } else {
 278                         topo->booted_cores = topo_package->booted_cores;
 279                 }
 280         }
 281 }
 282
 283 void store_topology(struct sysinfo_15_1_x *info)
 284 {
 285         stsi(info, 15, 1, topology_mnest_limit());
 286 }
 287
 288 static void __arch_update_dedicated_flag(void *arg)
 289 {
 290         if (topology_cpu_dedicated(smp_processor_id()))
 291                 set_cpu_flag(CIF_DEDICATED_CPU);
 292         else
 293                 clear_cpu_flag(CIF_DEDICATED_CPU);
 294 }
 295
 296 static int __arch_update_cpu_topology(void)
 297 {
 298         struct sysinfo_15_1_x *info = tl_info;
 299         int rc = 0;
 300
 301         mutex_lock(&smp_cpu_state_mutex);
 302         if (MACHINE_HAS_TOPOLOGY) {
 303                 rc = 1;
 304                 store_topology(info);
 305                 tl_to_masks(info);
 306         }
 307         update_cpu_masks();
 308         if (!MACHINE_HAS_TOPOLOGY)
 309                 topology_update_polarization_simple();
 310         mutex_unlock(&smp_cpu_state_mutex);
 311         return rc;
 312 }
 313
 314 int arch_update_cpu_topology(void)
 315 {
 316         struct device *dev;
 317         int cpu, rc;
 318
 319         rc = __arch_update_cpu_topology();
 320         on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
 321         for_each_online_cpu(cpu) {
 322                 dev = get_cpu_device(cpu);
 323                 if (dev)
 324                         kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 325         }
 326         return rc;
 327 }
 328
 329 static void topology_work_fn(struct work_struct *work)
 330 {
 331         rebuild_sched_domains();
 332 }
 333
 334 void topology_schedule_update(void)
 335 {
 336         schedule_work(&topology_work);
 337 }
 338
 339 static void topology_flush_work(void)
 340 {
 341         flush_work(&topology_work);
 342 }
 343
 344 static void topology_timer_fn(struct timer_list *unused)
 345 {
 346         if (ptf(PTF_CHECK))
 347                 topology_schedule_update();
 348         set_topology_timer();
 349 }
 350
 351 static struct timer_list topology_timer;
 352
 353 static atomic_t topology_poll = ATOMIC_INIT(0);
 354
 355 static void set_topology_timer(void)
 356 {
 357         if (atomic_add_unless(&topology_poll, -1, 0))
 358                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(100));
 359         else
 360                 mod_timer(&topology_timer, jiffies + msecs_to_jiffies(60 * MSEC_PER_SEC));
 361 }
 362
 363 void topology_expect_change(void)
 364 {
 365         if (!MACHINE_HAS_TOPOLOGY)
 366                 return;
 367         /* This is racy, but it doesn't matter since it is just a heuristic.
 368          * Worst case is that we poll in a higher frequency for a bit longer.
 369          */
 370         if (atomic_read(&topology_poll) > 60)
 371                 return;
 372         atomic_add(60, &topology_poll);
 373         set_topology_timer();
 374 }
 375
 376 static int cpu_management;
 377
 378 static ssize_t dispatching_show(struct device *dev,
 379                                 struct device_attribute *attr,
 380                                 char *buf)
 381 {
 382         ssize_t count;
 383
 384         mutex_lock(&smp_cpu_state_mutex);
 385         count = sprintf(buf, "%d\n", cpu_management);
 386         mutex_unlock(&smp_cpu_state_mutex);
 387         return count;
 388 }
 389
 390 static ssize_t dispatching_store(struct device *dev,
 391                                  struct device_attribute *attr,
 392                                  const char *buf,
 393                                  size_t count)
 394 {
 395         int val, rc;
 396         char delim;
 397
 398         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 399                 return -EINVAL;
 400         if (val != 0 && val != 1)
 401                 return -EINVAL;
 402         rc = 0;
 403         get_online_cpus();
 404         mutex_lock(&smp_cpu_state_mutex);
 405         if (cpu_management == val)
 406                 goto out;
 407         rc = topology_set_cpu_management(val);
 408         if (rc)
 409                 goto out;
 410         cpu_management = val;
 411         topology_expect_change();
 412 out:
 413         mutex_unlock(&smp_cpu_state_mutex);
 414         put_online_cpus();
 415         return rc ? rc : count;
 416 }
 417 static DEVICE_ATTR_RW(dispatching);
 418
 419 static ssize_t cpu_polarization_show(struct device *dev,
 420                                      struct device_attribute *attr, char *buf)
 421 {
 422         int cpu = dev->id;
 423         ssize_t count;
 424
 425         mutex_lock(&smp_cpu_state_mutex);
 426         switch (smp_cpu_get_polarization(cpu)) {
 427         case POLARIZATION_HRZ:
 428                 count = sprintf(buf, "horizontal\n");
 429                 break;
 430         case POLARIZATION_VL:
 431                 count = sprintf(buf, "vertical:low\n");
 432                 break;
 433         case POLARIZATION_VM:
 434                 count = sprintf(buf, "vertical:medium\n");
 435                 break;
 436         case POLARIZATION_VH:
 437                 count = sprintf(buf, "vertical:high\n");
 438                 break;
 439         default:
 440                 count = sprintf(buf, "unknown\n");
 441                 break;
 442         }
 443         mutex_unlock(&smp_cpu_state_mutex);
 444         return count;
 445 }
 446 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 447
 448 static struct attribute *topology_cpu_attrs[] = {
 449         &dev_attr_polarization.attr,
 450         NULL,
 451 };
 452
 453 static struct attribute_group topology_cpu_attr_group = {
 454         .attrs = topology_cpu_attrs,
 455 };
 456
 457 static ssize_t cpu_dedicated_show(struct device *dev,
 458                                   struct device_attribute *attr, char *buf)
 459 {
 460         int cpu = dev->id;
 461         ssize_t count;
 462
 463         mutex_lock(&smp_cpu_state_mutex);
 464         count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
 465         mutex_unlock(&smp_cpu_state_mutex);
 466         return count;
 467 }
 468 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 469
 470 static struct attribute *topology_extra_cpu_attrs[] = {
 471         &dev_attr_dedicated.attr,
 472         NULL,
 473 };
 474
 475 static struct attribute_group topology_extra_cpu_attr_group = {
 476         .attrs = topology_extra_cpu_attrs,
 477 };
 478
 479 int topology_cpu_init(struct cpu *cpu)
 480 {
 481         int rc;
 482
 483         rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 484         if (rc || !MACHINE_HAS_TOPOLOGY)
 485                 return rc;
 486         rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
 487         if (rc)
 488                 sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 489         return rc;
 490 }
 491
 492 static const struct cpumask *cpu_thread_mask(int cpu)
 493 {
 494         return &cpu_topology[cpu].thread_mask;
 495 }
 496
 497
 498 const struct cpumask *cpu_coregroup_mask(int cpu)
 499 {
 500         return &cpu_topology[cpu].core_mask;
 501 }
 502
 503 static const struct cpumask *cpu_book_mask(int cpu)
 504 {
 505         return &cpu_topology[cpu].book_mask;
 506 }
 507
 508 static const struct cpumask *cpu_drawer_mask(int cpu)
 509 {
 510         return &cpu_topology[cpu].drawer_mask;
 511 }
 512
 513 static struct sched_domain_topology_level s390_topology[] = {
 514         { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
 515         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 516         { cpu_book_mask, SD_INIT_NAME(BOOK) },
 517         { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
 518         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 519         { NULL, },
 520 };
 521
 522 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 523                                struct mask_info *mask, int offset)
 524 {
 525         int i, nr_masks;
 526
 527         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 528         for (i = 0; i < info->mnest - offset; i++)
 529                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 530         nr_masks = max(nr_masks, 1);
 531         for (i = 0; i < nr_masks; i++) {
 532                 mask->next = memblock_alloc(sizeof(*mask->next), 8);
 533                 if (!mask->next)
 534                         panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 535                               __func__, sizeof(*mask->next), 8);
 536                 mask = mask->next;
 537         }
 538 }
 539
 540 void __init topology_init_early(void)
 541 {
 542         struct sysinfo_15_1_x *info;
 543
 544         set_sched_topology(s390_topology);
 545         if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
 546                 if (MACHINE_HAS_TOPOLOGY)
 547                         topology_mode = TOPOLOGY_MODE_HW;
 548                 else
 549                         topology_mode = TOPOLOGY_MODE_SINGLE;
 550         }
 551         if (!MACHINE_HAS_TOPOLOGY)
 552                 goto out;
 553         tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 554         if (!tl_info)
 555                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 556                       __func__, PAGE_SIZE, PAGE_SIZE);
 557         info = tl_info;
 558         store_topology(info);
 559         pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
 560                 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
 561                 info->mag[4], info->mag[5], info->mnest);
 562         alloc_masks(info, &socket_info, 1);
 563         alloc_masks(info, &book_info, 2);
 564         alloc_masks(info, &drawer_info, 3);
 565 out:
 566         __arch_update_cpu_topology();
 567         __arch_update_dedicated_flag(NULL);
 568 }
 569
 570 static inline int topology_get_mode(int enabled)
 571 {
 572         if (!enabled)
 573                 return TOPOLOGY_MODE_SINGLE;
 574         return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
 575 }
 576
 577 static inline int topology_is_enabled(void)
 578 {
 579         return topology_mode != TOPOLOGY_MODE_SINGLE;
 580 }
 581
 582 static int __init topology_setup(char *str)
 583 {
 584         bool enabled;
 585         int rc;
 586
 587         rc = kstrtobool(str, &enabled);
 588         if (rc)
 589                 return rc;
 590         topology_mode = topology_get_mode(enabled);
 591         return 0;
 592 }
 593 early_param("topology", topology_setup);
 594
 595 static int topology_ctl_handler(struct ctl_table *ctl, int write,
 596                                 void *buffer, size_t *lenp, loff_t *ppos)
 597 {
 598         int enabled = topology_is_enabled();
 599         int new_mode;
 600         int rc;
 601         struct ctl_table ctl_entry = {
 602                 .procname       = ctl->procname,
 603                 .data           = &enabled,
 604                 .maxlen         = sizeof(int),
 605                 .extra1         = SYSCTL_ZERO,
 606                 .extra2         = SYSCTL_ONE,
 607         };
 608
 609         rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 610         if (rc < 0 || !write)
 611                 return rc;
 612
 613         mutex_lock(&smp_cpu_state_mutex);
 614         new_mode = topology_get_mode(enabled);
 615         if (topology_mode != new_mode) {
 616                 topology_mode = new_mode;
 617                 topology_schedule_update();
 618         }
 619         mutex_unlock(&smp_cpu_state_mutex);
 620         topology_flush_work();
 621
 622         return rc;
 623 }
 624
 625 static struct ctl_table topology_ctl_table[] = {
 626         {
 627                 .procname       = "topology",
 628                 .mode           = 0644,
 629                 .proc_handler   = topology_ctl_handler,
 630         },
 631         { },
 632 };
 633
 634 static struct ctl_table topology_dir_table[] = {
 635         {
 636                 .procname       = "s390",
 637                 .maxlen         = 0,
 638                 .mode           = 0555,
 639                 .child          = topology_ctl_table,
 640         },
 641         { },
 642 };
 643
 644 static int __init topology_init(void)
 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_table(topology_dir_table);
 652         return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 653 }
 654 device_initcall(topology_init);