linux/arch/s390/kernel/topology.c
<<
>>
Prefs
   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
  33enum {
  34        TOPOLOGY_MODE_HW,
  35        TOPOLOGY_MODE_SINGLE,
  36        TOPOLOGY_MODE_PACKAGE,
  37        TOPOLOGY_MODE_UNINITIALIZED
  38};
  39
  40struct mask_info {
  41        struct mask_info *next;
  42        unsigned char id;
  43        cpumask_t mask;
  44};
  45
  46static int topology_mode = TOPOLOGY_MODE_UNINITIALIZED;
  47static void set_topology_timer(void);
  48static void topology_work_fn(struct work_struct *work);
  49static struct sysinfo_15_1_x *tl_info;
  50
  51static 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 */
  57static struct mask_info socket_info;
  58static struct mask_info book_info;
  59static struct mask_info drawer_info;
  60
  61struct cpu_topology_s390 cpu_topology[NR_CPUS];
  62EXPORT_SYMBOL_GPL(cpu_topology);
  63
  64static 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);
  91out:
  92        cpumask_copy(dst, &mask);
  93}
  94
  95static 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        }
 111out:
 112        cpumask_copy(dst, &mask);
 113}
 114
 115#define TOPOLOGY_CORE_BITS      64
 116
 117static 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
 149static 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
 170static 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
 177static 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
 212static 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
 220static 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
 233int 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
 250void 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
 288void store_topology(struct sysinfo_15_1_x *info)
 289{
 290        stsi(info, 15, 1, topology_mnest_limit());
 291}
 292
 293static 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
 301static 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
 319int 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
 334static void topology_work_fn(struct work_struct *work)
 335{
 336        rebuild_sched_domains();
 337}
 338
 339void topology_schedule_update(void)
 340{
 341        schedule_work(&topology_work);
 342}
 343
 344static void topology_flush_work(void)
 345{
 346        flush_work(&topology_work);
 347}
 348
 349static void topology_timer_fn(struct timer_list *unused)
 350{
 351        if (ptf(PTF_CHECK))
 352                topology_schedule_update();
 353        set_topology_timer();
 354}
 355
 356static struct timer_list topology_timer;
 357
 358static atomic_t topology_poll = ATOMIC_INIT(0);
 359
 360static 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
 368void 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
 381static int cpu_management;
 382
 383static 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
 395static 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();
 417out:
 418        mutex_unlock(&smp_cpu_state_mutex);
 419        cpus_read_unlock();
 420        return rc ? rc : count;
 421}
 422static DEVICE_ATTR_RW(dispatching);
 423
 424static 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}
 451static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 452
 453static struct attribute *topology_cpu_attrs[] = {
 454        &dev_attr_polarization.attr,
 455        NULL,
 456};
 457
 458static struct attribute_group topology_cpu_attr_group = {
 459        .attrs = topology_cpu_attrs,
 460};
 461
 462static 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}
 473static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
 474
 475static struct attribute *topology_extra_cpu_attrs[] = {
 476        &dev_attr_dedicated.attr,
 477        NULL,
 478};
 479
 480static struct attribute_group topology_extra_cpu_attr_group = {
 481        .attrs = topology_extra_cpu_attrs,
 482};
 483
 484int 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
 497static const struct cpumask *cpu_thread_mask(int cpu)
 498{
 499        return &cpu_topology[cpu].thread_mask;
 500}
 501
 502
 503const struct cpumask *cpu_coregroup_mask(int cpu)
 504{
 505        return &cpu_topology[cpu].core_mask;
 506}
 507
 508static const struct cpumask *cpu_book_mask(int cpu)
 509{
 510        return &cpu_topology[cpu].book_mask;
 511}
 512
 513static const struct cpumask *cpu_drawer_mask(int cpu)
 514{
 515        return &cpu_topology[cpu].drawer_mask;
 516}
 517
 518static 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
 527static 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
 545void __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);
 570out:
 571        cpumask_set_cpu(0, &cpu_setup_mask);
 572        __arch_update_cpu_topology();
 573        __arch_update_dedicated_flag(NULL);
 574}
 575
 576static 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
 583static inline int topology_is_enabled(void)
 584{
 585        return topology_mode != TOPOLOGY_MODE_SINGLE;
 586}
 587
 588static 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}
 599early_param("topology", topology_setup);
 600
 601static 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
 631static struct ctl_table topology_ctl_table[] = {
 632        {
 633                .procname       = "topology",
 634                .mode           = 0644,
 635                .proc_handler   = topology_ctl_handler,
 636        },
 637        { },
 638};
 639
 640static struct ctl_table topology_dir_table[] = {
 641        {
 642                .procname       = "s390",
 643                .maxlen         = 0,
 644                .mode           = 0555,
 645                .child          = topology_ctl_table,
 646        },
 647        { },
 648};
 649
 650static int __init topology_init(void)
 651{
 652        timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
 653        if (MACHINE_HAS_TOPOLOGY)
 654                set_topology_timer();
 655        else
 656                topology_update_polarization_simple();
 657        register_sysctl_table(topology_dir_table);
 658        return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 659}
 660device_initcall(topology_init);
 661