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 #include <asm/numa.h>
  30
  31 #define PTF_HORIZONTAL  (0UL)
  32 #define PTF_VERTICAL    (1UL)
  33 #define PTF_CHECK       (2UL)
  34
  35 enum {
  36         TOPOLOGY_MODE_HW,
  37         TOPOLOGY_MODE_SINGLE,
  38         TOPOLOGY_MODE_PACKAGE,
  39         TOPOLOGY_MODE_UNINITIALIZED
  40 };
  41
  42 struct mask_info {
  43         struct mask_info *next;
  44         unsigned char id;
  45         cpumask_t mask;
  46 };
  47
  48 static int topology_mode = TOPOLOGY_MODE_UNINITIALIZED;
  49 static void set_topology_timer(void);
  50 static void topology_work_fn(struct work_struct *work);
  51 static struct sysinfo_15_1_x *tl_info;
  52
  53 static DECLARE_WORK(topology_work, topology_work_fn);
  54
  55 /*
  56  * Socket/Book linked lists and cpu_topology updates are
  57  * protected by "sched_domains_mutex".
  58  */
  59 static struct mask_info socket_info;
  60 static struct mask_info book_info;
  61 static struct mask_info drawer_info;
  62
  63 struct cpu_topology_s390 cpu_topology[NR_CPUS];
  64 EXPORT_SYMBOL_GPL(cpu_topology);
  65
  66 cpumask_t cpus_with_topology;
  67
  68 static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
  69 {
  70         cpumask_t mask;
  71
  72         cpumask_copy(&mask, cpumask_of(cpu));
  73         switch (topology_mode) {
  74         case TOPOLOGY_MODE_HW:
  75                 while (info) {
  76                         if (cpumask_test_cpu(cpu, &info->mask)) {
  77                                 mask = info->mask;
  78                                 break;
  79                         }
  80                         info = info->next;
  81                 }
  82                 if (cpumask_empty(&mask))
  83                         cpumask_copy(&mask, cpumask_of(cpu));
  84                 break;
  85         case TOPOLOGY_MODE_PACKAGE:
  86                 cpumask_copy(&mask, cpu_present_mask);
  87                 break;
  88         default:
  89                 /* fallthrough */
  90         case TOPOLOGY_MODE_SINGLE:
  91                 cpumask_copy(&mask, cpumask_of(cpu));
  92                 break;
  93         }
  94         return mask;
  95 }
  96
  97 static cpumask_t cpu_thread_map(unsigned int cpu)
  98 {
  99         cpumask_t mask;
 100         int i;
 101
 102         cpumask_copy(&mask, cpumask_of(cpu));
 103         if (topology_mode != TOPOLOGY_MODE_HW)
 104                 return mask;
 105         cpu -= cpu % (smp_cpu_mtid + 1);
 106         for (i = 0; i <= smp_cpu_mtid; i++)
 107                 if (cpu_present(cpu + i))
 108                         cpumask_set_cpu(cpu + i, &mask);
 109         return mask;
 110 }
 111
 112 #define TOPOLOGY_CORE_BITS      64
 113
 114 static void add_cpus_to_mask(struct topology_core *tl_core,
 115                              struct mask_info *drawer,
 116                              struct mask_info *book,
 117                              struct mask_info *socket)
 118 {
 119         struct cpu_topology_s390 *topo;
 120         unsigned int core;
 121
 122         for_each_set_bit(core, &tl_core->mask, TOPOLOGY_CORE_BITS) {
 123                 unsigned int rcore;
 124                 int lcpu, i;
 125
 126                 rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
 127                 lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
 128                 if (lcpu < 0)
 129                         continue;
 130                 for (i = 0; i <= smp_cpu_mtid; i++) {
 131                         topo = &cpu_topology[lcpu + i];
 132                         topo->drawer_id = drawer->id;
 133                         topo->book_id = book->id;
 134                         topo->socket_id = socket->id;
 135                         topo->core_id = rcore;
 136                         topo->thread_id = lcpu + i;
 137                         topo->dedicated = tl_core->d;
 138                         cpumask_set_cpu(lcpu + i, &drawer->mask);
 139                         cpumask_set_cpu(lcpu + i, &book->mask);
 140                         cpumask_set_cpu(lcpu + i, &socket->mask);
 141                         cpumask_set_cpu(lcpu + i, &cpus_with_topology);
 142                         smp_cpu_set_polarization(lcpu + i, tl_core->pp);
 143                 }
 144         }
 145 }
 146
 147 static void clear_masks(void)
 148 {
 149         struct mask_info *info;
 150
 151         info = &socket_info;
 152         while (info) {
 153                 cpumask_clear(&info->mask);
 154                 info = info->next;
 155         }
 156         info = &book_info;
 157         while (info) {
 158                 cpumask_clear(&info->mask);
 159                 info = info->next;
 160         }
 161         info = &drawer_info;
 162         while (info) {
 163                 cpumask_clear(&info->mask);
 164                 info = info->next;
 165         }
 166 }
 167
 168 static union topology_entry *next_tle(union topology_entry *tle)
 169 {
 170         if (!tle->nl)
 171                 return (union topology_entry *)((struct topology_core *)tle + 1);
 172         return (union topology_entry *)((struct topology_container *)tle + 1);
 173 }
 174
 175 static void tl_to_masks(struct sysinfo_15_1_x *info)
 176 {
 177         struct mask_info *socket = &socket_info;
 178         struct mask_info *book = &book_info;
 179         struct mask_info *drawer = &drawer_info;
 180         union topology_entry *tle, *end;
 181
 182         clear_masks();
 183         tle = info->tle;
 184         end = (union topology_entry *)((unsigned long)info + info->length);
 185         while (tle < end) {
 186                 switch (tle->nl) {
 187                 case 3:
 188                         drawer = drawer->next;
 189                         drawer->id = tle->container.id;
 190                         break;
 191                 case 2:
 192                         book = book->next;
 193                         book->id = tle->container.id;
 194                         break;
 195                 case 1:
 196                         socket = socket->next;
 197                         socket->id = tle->container.id;
 198                         break;
 199                 case 0:
 200                         add_cpus_to_mask(&tle->cpu, drawer, book, socket);
 201                         break;
 202                 default:
 203                         clear_masks();
 204                         return;
 205                 }
 206                 tle = next_tle(tle);
 207         }
 208 }
 209
 210 static void topology_update_polarization_simple(void)
 211 {
 212         int cpu;
 213
 214         for_each_possible_cpu(cpu)
 215                 smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
 216 }
 217
 218 static int ptf(unsigned long fc)
 219 {
 220         int rc;
 221
 222         asm volatile(
 223                 "       .insn   rre,0xb9a20000,%1,%1\n"
 224                 "       ipm     %0\n"
 225                 "       srl     %0,28\n"
 226                 : "=d" (rc)
 227                 : "d" (fc)  : "cc");
 228         return rc;
 229 }
 230
 231 int topology_set_cpu_management(int fc)
 232 {
 233         int cpu, rc;
 234
 235         if (!MACHINE_HAS_TOPOLOGY)
 236                 return -EOPNOTSUPP;
 237         if (fc)
 238                 rc = ptf(PTF_VERTICAL);
 239         else
 240                 rc = ptf(PTF_HORIZONTAL);
 241         if (rc)
 242                 return -EBUSY;
 243         for_each_possible_cpu(cpu)
 244                 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 245         return rc;
 246 }
 247
 248 static void update_cpu_masks(void)
 249 {
 250         struct cpu_topology_s390 *topo;
 251         int cpu, id;
 252
 253         for_each_possible_cpu(cpu) {
 254                 topo = &cpu_topology[cpu];
 255                 topo->thread_mask = cpu_thread_map(cpu);
 256                 topo->core_mask = cpu_group_map(&socket_info, cpu);
 257                 topo->book_mask = cpu_group_map(&book_info, cpu);
 258                 topo->drawer_mask = cpu_group_map(&drawer_info, cpu);
 259                 if (topology_mode != TOPOLOGY_MODE_HW) {
 260                         id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
 261                         topo->thread_id = cpu;
 262                         topo->core_id = cpu;
 263                         topo->socket_id = id;
 264                         topo->book_id = id;
 265                         topo->drawer_id = id;
 266                         if (cpu_present(cpu))
 267                                 cpumask_set_cpu(cpu, &cpus_with_topology);
 268                 }
 269         }
 270         numa_update_cpu_topology();
 271 }
 272
 273 void store_topology(struct sysinfo_15_1_x *info)
 274 {
 275         stsi(info, 15, 1, topology_mnest_limit());
 276 }
 277
 278 static void __arch_update_dedicated_flag(void *arg)
 279 {
 280         if (topology_cpu_dedicated(smp_processor_id()))
 281                 set_cpu_flag(CIF_DEDICATED_CPU);
 282         else
 283                 clear_cpu_flag(CIF_DEDICATED_CPU);
 284 }
 285
 286 static int __arch_update_cpu_topology(void)
 287 {
 288         struct sysinfo_15_1_x *info = tl_info;
 289         int rc = 0;
 290
 291         mutex_lock(&smp_cpu_state_mutex);
 292         cpumask_clear(&cpus_with_topology);
 293         if (MACHINE_HAS_TOPOLOGY) {
 294                 rc = 1;
 295                 store_topology(info);
 296                 tl_to_masks(info);
 297         }
 298         update_cpu_masks();
 299         if (!MACHINE_HAS_TOPOLOGY)
 300                 topology_update_polarization_simple();
 301         mutex_unlock(&smp_cpu_state_mutex);
 302         return rc;
 303 }
 304
 305 int arch_update_cpu_topology(void)
 306 {
 307         struct device *dev;
 308         int cpu, rc;
 309
 310         rc = __arch_update_cpu_topology();
 311         on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
 312         for_each_online_cpu(cpu) {
 313                 dev = get_cpu_device(cpu);
 314                 kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 315         }
 316         return rc;
 317 }
 318
 319 static void topology_work_fn(struct work_struct *work)
 320 {
 321         rebuild_sched_domains();
 322 }
 323
 324 void topology_schedule_update(void)
 325 {
 326         schedule_work(&topology_work);
 327 }
 328
 329 static void topology_flush_work(void)
 330 {
 331         flush_work(&topology_work);
 332 }
 333
 334 static void topology_timer_fn(struct timer_list *unused)
 335 {
 336         if (ptf(PTF_CHECK))
 337                 topology_schedule_update();
 338         set_topology_timer();
 339 }
 340
 341 static struct timer_list topology_timer;
 342
 343 static atomic_t topology_poll = ATOMIC_INIT(0);
 344
 345 static void set_topology_timer(void)
 346 {
 347         if (atomic_add_unless(&topology_poll, -1, 0))
 348                 mod_timer(&topology_timer, jiffies + HZ / 10);
 349         else
 350                 mod_timer(&topology_timer, jiffies + HZ * 60);
 351 }
 352
 353 void topology_expect_change(void)
 354 {
 355         if (!MACHINE_HAS_TOPOLOGY)
 356                 return;
 357         /* This is racy, but it doesn't matter since it is just a heuristic.
 358          * Worst case is that we poll in a higher frequency for a bit longer.
 359          */
 360         if (atomic_read(&topology_poll) > 60)
 361                 return;
 362         atomic_add(60, &topology_poll);
 363         set_topology_timer();
 364 }
 365
 366 static int cpu_management;
 367
 368 static ssize_t dispatching_show(struct device *dev,
 369                                 struct device_attribute *attr,
 370                                 char *buf)
 371 {
 372         ssize_t count;
 373
 374         mutex_lock(&smp_cpu_state_mutex);
 375         count = sprintf(buf, "%d\n", cpu_management);
 376         mutex_unlock(&smp_cpu_state_mutex);
 377         return count;
 378 }
 379
 380 static ssize_t dispatching_store(struct device *dev,
 381                                  struct device_attribute *attr,
 382                                  const char *buf,
 383                                  size_t count)
 384 {
 385         int val, rc;
 386         char delim;
 387
 388         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 389                 return -EINVAL;
 390         if (val != 0 && val != 1)
 391                 return -EINVAL;
 392         rc = 0;
 393         get_online_cpus();
 394         mutex_lock(&smp_cpu_state_mutex);
 395         if (cpu_management == val)
 396                 goto out;
 397         rc = topology_set_cpu_management(val);
 398         if (rc)
 399                 goto out;
 400         cpu_management = val;
 401         topology_expect_change();
 402 out:
 403         mutex_unlock(&smp_cpu_state_mutex);
 404         put_online_cpus();
 405         return rc ? rc : count;
 406 }
 407 static DEVICE_ATTR_RW(dispatching);
 408
 409 static ssize_t cpu_polarization_show(struct device *dev,
 410                                      struct device_attribute *attr, char *buf)
 411 {
 412         int cpu = dev->id;
 413         ssize_t count;
 414
 415         mutex_lock(&smp_cpu_state_mutex);
 416         switch (smp_cpu_get_polarization(cpu)) {
 417         case POLARIZATION_HRZ:
 418                 count = sprintf(buf, "horizontal\n");
 419                 break;
 420         case POLARIZATION_VL:
 421                 count = sprintf(buf, "vertical:low\n");
 422                 break;
 423         case POLARIZATION_VM:
 424                 count = sprintf(buf, "vertical:medium\n");
 425                 break;
 426         case POLARIZATION_VH:
 427                 count = sprintf(buf, "vertical:high\n");
 428                 break;
 429         default:
 430                 count = sprintf(buf, "unknown\n");
 431                 break;
 432         }
 433         mutex_unlock(&smp_cpu_state_mutex);
 434         return count;
 435 }
 436 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 437
 438 static struct attribute *topology_cpu_attrs[] = {
 439         &dev_attr_polarization.attr,
 440         NULL,
 441 };
 442
 443 static struct attribute_group topology_cpu_attr_group = {
 444         .attrs = topology_cpu_attrs,
 445 };
 446
 447 static ssize_t cpu_dedicated_show(struct device *dev,
 448                                   struct device_attribute *attr, char *buf)
 449 {
 450         int cpu = dev->id;
 451         ssize_t count;
 452
 453         mutex_lock(&smp_cpu_state_mutex);
 454         count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
 455         mutex_unlock(&smp_cpu_state_mutex);
 456         return count;
 457 }
 458 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 459
 460 static struct attribute *topology_extra_cpu_attrs[] = {
 461         &dev_attr_dedicated.attr,
 462         NULL,
 463 };
 464
 465 static struct attribute_group topology_extra_cpu_attr_group = {
 466         .attrs = topology_extra_cpu_attrs,
 467 };
 468
 469 int topology_cpu_init(struct cpu *cpu)
 470 {
 471         int rc;
 472
 473         rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 474         if (rc || !MACHINE_HAS_TOPOLOGY)
 475                 return rc;
 476         rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
 477         if (rc)
 478                 sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 479         return rc;
 480 }
 481
 482 static const struct cpumask *cpu_thread_mask(int cpu)
 483 {
 484         return &cpu_topology[cpu].thread_mask;
 485 }
 486
 487
 488 const struct cpumask *cpu_coregroup_mask(int cpu)
 489 {
 490         return &cpu_topology[cpu].core_mask;
 491 }
 492
 493 static const struct cpumask *cpu_book_mask(int cpu)
 494 {
 495         return &cpu_topology[cpu].book_mask;
 496 }
 497
 498 static const struct cpumask *cpu_drawer_mask(int cpu)
 499 {
 500         return &cpu_topology[cpu].drawer_mask;
 501 }
 502
 503 static struct sched_domain_topology_level s390_topology[] = {
 504         { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
 505         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 506         { cpu_book_mask, SD_INIT_NAME(BOOK) },
 507         { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
 508         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 509         { NULL, },
 510 };
 511
 512 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 513                                struct mask_info *mask, int offset)
 514 {
 515         int i, nr_masks;
 516
 517         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 518         for (i = 0; i < info->mnest - offset; i++)
 519                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 520         nr_masks = max(nr_masks, 1);
 521         for (i = 0; i < nr_masks; i++) {
 522                 mask->next = memblock_alloc(sizeof(*mask->next), 8);
 523                 if (!mask->next)
 524                         panic("%s: Failed to allocate %zu bytes align=0x%x\n",
 525                               __func__, sizeof(*mask->next), 8);
 526                 mask = mask->next;
 527         }
 528 }
 529
 530 void __init topology_init_early(void)
 531 {
 532         struct sysinfo_15_1_x *info;
 533
 534         set_sched_topology(s390_topology);
 535         if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
 536                 if (MACHINE_HAS_TOPOLOGY)
 537                         topology_mode = TOPOLOGY_MODE_HW;
 538                 else
 539                         topology_mode = TOPOLOGY_MODE_SINGLE;
 540         }
 541         if (!MACHINE_HAS_TOPOLOGY)
 542                 goto out;
 543         tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 544         if (!tl_info)
 545                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
 546                       __func__, PAGE_SIZE, PAGE_SIZE);
 547         info = tl_info;
 548         store_topology(info);
 549         pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
 550                 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
 551                 info->mag[4], info->mag[5], info->mnest);
 552         alloc_masks(info, &socket_info, 1);
 553         alloc_masks(info, &book_info, 2);
 554         alloc_masks(info, &drawer_info, 3);
 555 out:
 556         __arch_update_cpu_topology();
 557         __arch_update_dedicated_flag(NULL);
 558 }
 559
 560 static inline int topology_get_mode(int enabled)
 561 {
 562         if (!enabled)
 563                 return TOPOLOGY_MODE_SINGLE;
 564         return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
 565 }
 566
 567 static inline int topology_is_enabled(void)
 568 {
 569         return topology_mode != TOPOLOGY_MODE_SINGLE;
 570 }
 571
 572 static int __init topology_setup(char *str)
 573 {
 574         bool enabled;
 575         int rc;
 576
 577         rc = kstrtobool(str, &enabled);
 578         if (rc)
 579                 return rc;
 580         topology_mode = topology_get_mode(enabled);
 581         return 0;
 582 }
 583 early_param("topology", topology_setup);
 584
 585 static int topology_ctl_handler(struct ctl_table *ctl, int write,
 586                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 587 {
 588         int enabled = topology_is_enabled();
 589         int new_mode;
 590         int rc;
 591         struct ctl_table ctl_entry = {
 592                 .procname       = ctl->procname,
 593                 .data           = &enabled,
 594                 .maxlen         = sizeof(int),
 595                 .extra1         = SYSCTL_ZERO,
 596                 .extra2         = SYSCTL_ONE,
 597         };
 598
 599         rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
 600         if (rc < 0 || !write)
 601                 return rc;
 602
 603         mutex_lock(&smp_cpu_state_mutex);
 604         new_mode = topology_get_mode(enabled);
 605         if (topology_mode != new_mode) {
 606                 topology_mode = new_mode;
 607                 topology_schedule_update();
 608         }
 609         mutex_unlock(&smp_cpu_state_mutex);
 610         topology_flush_work();
 611
 612         return rc;
 613 }
 614
 615 static struct ctl_table topology_ctl_table[] = {
 616         {
 617                 .procname       = "topology",
 618                 .mode           = 0644,
 619                 .proc_handler   = topology_ctl_handler,
 620         },
 621         { },
 622 };
 623
 624 static struct ctl_table topology_dir_table[] = {
 625         {
 626                 .procname       = "s390",
 627                 .maxlen         = 0,
 628                 .mode           = 0555,
 629                 .child          = topology_ctl_table,
 630         },
 631         { },
 632 };
 633
 634 static int __init topology_init(void)
 635 {
 636         timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 637         if (MACHINE_HAS_TOPOLOGY)
 638                 set_topology_timer();
 639         else
 640                 topology_update_polarization_simple();
 641         register_sysctl_table(topology_dir_table);
 642         return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 643 }
 644 device_initcall(topology_init);