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/bootmem.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(dispatching, 0644, dispatching_show,
 408                          dispatching_store);
 409
 410 static ssize_t cpu_polarization_show(struct device *dev,
 411                                      struct device_attribute *attr, char *buf)
 412 {
 413         int cpu = dev->id;
 414         ssize_t count;
 415
 416         mutex_lock(&smp_cpu_state_mutex);
 417         switch (smp_cpu_get_polarization(cpu)) {
 418         case POLARIZATION_HRZ:
 419                 count = sprintf(buf, "horizontal\n");
 420                 break;
 421         case POLARIZATION_VL:
 422                 count = sprintf(buf, "vertical:low\n");
 423                 break;
 424         case POLARIZATION_VM:
 425                 count = sprintf(buf, "vertical:medium\n");
 426                 break;
 427         case POLARIZATION_VH:
 428                 count = sprintf(buf, "vertical:high\n");
 429                 break;
 430         default:
 431                 count = sprintf(buf, "unknown\n");
 432                 break;
 433         }
 434         mutex_unlock(&smp_cpu_state_mutex);
 435         return count;
 436 }
 437 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 438
 439 static struct attribute *topology_cpu_attrs[] = {
 440         &dev_attr_polarization.attr,
 441         NULL,
 442 };
 443
 444 static struct attribute_group topology_cpu_attr_group = {
 445         .attrs = topology_cpu_attrs,
 446 };
 447
 448 static ssize_t cpu_dedicated_show(struct device *dev,
 449                                   struct device_attribute *attr, char *buf)
 450 {
 451         int cpu = dev->id;
 452         ssize_t count;
 453
 454         mutex_lock(&smp_cpu_state_mutex);
 455         count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
 456         mutex_unlock(&smp_cpu_state_mutex);
 457         return count;
 458 }
 459 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 460
 461 static struct attribute *topology_extra_cpu_attrs[] = {
 462         &dev_attr_dedicated.attr,
 463         NULL,
 464 };
 465
 466 static struct attribute_group topology_extra_cpu_attr_group = {
 467         .attrs = topology_extra_cpu_attrs,
 468 };
 469
 470 int topology_cpu_init(struct cpu *cpu)
 471 {
 472         int rc;
 473
 474         rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 475         if (rc || !MACHINE_HAS_TOPOLOGY)
 476                 return rc;
 477         rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
 478         if (rc)
 479                 sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 480         return rc;
 481 }
 482
 483 static const struct cpumask *cpu_thread_mask(int cpu)
 484 {
 485         return &cpu_topology[cpu].thread_mask;
 486 }
 487
 488
 489 const struct cpumask *cpu_coregroup_mask(int cpu)
 490 {
 491         return &cpu_topology[cpu].core_mask;
 492 }
 493
 494 static const struct cpumask *cpu_book_mask(int cpu)
 495 {
 496         return &cpu_topology[cpu].book_mask;
 497 }
 498
 499 static const struct cpumask *cpu_drawer_mask(int cpu)
 500 {
 501         return &cpu_topology[cpu].drawer_mask;
 502 }
 503
 504 static struct sched_domain_topology_level s390_topology[] = {
 505         { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
 506         { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
 507         { cpu_book_mask, SD_INIT_NAME(BOOK) },
 508         { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
 509         { cpu_cpu_mask, SD_INIT_NAME(DIE) },
 510         { NULL, },
 511 };
 512
 513 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 514                                struct mask_info *mask, int offset)
 515 {
 516         int i, nr_masks;
 517
 518         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 519         for (i = 0; i < info->mnest - offset; i++)
 520                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 521         nr_masks = max(nr_masks, 1);
 522         for (i = 0; i < nr_masks; i++) {
 523                 mask->next = memblock_virt_alloc(sizeof(*mask->next), 8);
 524                 mask = mask->next;
 525         }
 526 }
 527
 528 void __init topology_init_early(void)
 529 {
 530         struct sysinfo_15_1_x *info;
 531
 532         set_sched_topology(s390_topology);
 533         if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
 534                 if (MACHINE_HAS_TOPOLOGY)
 535                         topology_mode = TOPOLOGY_MODE_HW;
 536                 else
 537                         topology_mode = TOPOLOGY_MODE_SINGLE;
 538         }
 539         if (!MACHINE_HAS_TOPOLOGY)
 540                 goto out;
 541         tl_info = memblock_virt_alloc(PAGE_SIZE, PAGE_SIZE);
 542         info = tl_info;
 543         store_topology(info);
 544         pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
 545                 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
 546                 info->mag[4], info->mag[5], info->mnest);
 547         alloc_masks(info, &socket_info, 1);
 548         alloc_masks(info, &book_info, 2);
 549         alloc_masks(info, &drawer_info, 3);
 550 out:
 551         __arch_update_cpu_topology();
 552         __arch_update_dedicated_flag(NULL);
 553 }
 554
 555 static inline int topology_get_mode(int enabled)
 556 {
 557         if (!enabled)
 558                 return TOPOLOGY_MODE_SINGLE;
 559         return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
 560 }
 561
 562 static inline int topology_is_enabled(void)
 563 {
 564         return topology_mode != TOPOLOGY_MODE_SINGLE;
 565 }
 566
 567 static int __init topology_setup(char *str)
 568 {
 569         bool enabled;
 570         int rc;
 571
 572         rc = kstrtobool(str, &enabled);
 573         if (rc)
 574                 return rc;
 575         topology_mode = topology_get_mode(enabled);
 576         return 0;
 577 }
 578 early_param("topology", topology_setup);
 579
 580 static int topology_ctl_handler(struct ctl_table *ctl, int write,
 581                                 void __user *buffer, size_t *lenp, loff_t *ppos)
 582 {
 583         unsigned int len;
 584         int new_mode;
 585         char buf[2];
 586
 587         if (!*lenp || *ppos) {
 588                 *lenp = 0;
 589                 return 0;
 590         }
 591         if (!write) {
 592                 strncpy(buf, topology_is_enabled() ? "1\n" : "0\n",
 593                         ARRAY_SIZE(buf));
 594                 len = strnlen(buf, ARRAY_SIZE(buf));
 595                 if (len > *lenp)
 596                         len = *lenp;
 597                 if (copy_to_user(buffer, buf, len))
 598                         return -EFAULT;
 599                 goto out;
 600         }
 601         len = *lenp;
 602         if (copy_from_user(buf, buffer, len > sizeof(buf) ? sizeof(buf) : len))
 603                 return -EFAULT;
 604         if (buf[0] != '0' && buf[0] != '1')
 605                 return -EINVAL;
 606         mutex_lock(&smp_cpu_state_mutex);
 607         new_mode = topology_get_mode(buf[0] == '1');
 608         if (topology_mode != new_mode) {
 609                 topology_mode = new_mode;
 610                 topology_schedule_update();
 611         }
 612         mutex_unlock(&smp_cpu_state_mutex);
 613         topology_flush_work();
 614 out:
 615         *lenp = len;
 616         *ppos += len;
 617         return 0;
 618 }
 619
 620 static struct ctl_table topology_ctl_table[] = {
 621         {
 622                 .procname       = "topology",
 623                 .mode           = 0644,
 624                 .proc_handler   = topology_ctl_handler,
 625         },
 626         { },
 627 };
 628
 629 static struct ctl_table topology_dir_table[] = {
 630         {
 631                 .procname       = "s390",
 632                 .maxlen         = 0,
 633                 .mode           = 0555,
 634                 .child          = topology_ctl_table,
 635         },
 636         { },
 637 };
 638
 639 static int __init topology_init(void)
 640 {
 641         timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 642         if (MACHINE_HAS_TOPOLOGY)
 643                 set_topology_timer();
 644         else
 645                 topology_update_polarization_simple();
 646         register_sysctl_table(topology_dir_table);
 647         return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 648 }
 649 device_initcall(topology_init);