arch/s390/kernel/topology.c

   1 /*
   2  *    Copyright IBM Corp. 2007, 2011
   3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
   4  */
   5
   6 #define KMSG_COMPONENT "cpu"
   7 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
   8
   9 #include <linux/workqueue.h>
  10 #include <linux/bootmem.h>
  11 #include <linux/cpuset.h>
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/sched.h>
  15 #include <linux/init.h>
  16 #include <linux/delay.h>
  17 #include <linux/cpu.h>
  18 #include <linux/smp.h>
  19 #include <linux/mm.h>
  20
  21 #define PTF_HORIZONTAL  (0UL)
  22 #define PTF_VERTICAL    (1UL)
  23 #define PTF_CHECK       (2UL)
  24
  25 struct mask_info {
  26         struct mask_info *next;
  27         unsigned char id;
  28         cpumask_t mask;
  29 };
  30
  31 static int topology_enabled = 1;
  32 static void topology_work_fn(struct work_struct *work);
  33 static struct sysinfo_15_1_x *tl_info;
  34 static void set_topology_timer(void);
  35 static DECLARE_WORK(topology_work, topology_work_fn);
  36 /* topology_lock protects the core linked list */
  37 static DEFINE_SPINLOCK(topology_lock);
  38
  39 static struct mask_info core_info;
  40 cpumask_t cpu_core_map[NR_CPUS];
  41 unsigned char cpu_core_id[NR_CPUS];
  42
  43 static struct mask_info book_info;
  44 cpumask_t cpu_book_map[NR_CPUS];
  45 unsigned char cpu_book_id[NR_CPUS];
  46
  47 /* smp_cpu_state_mutex must be held when accessing this array */
  48 int cpu_polarization[NR_CPUS];
  49
  50 static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
  51 {
  52         cpumask_t mask;
  53
  54         cpumask_clear(&mask);
  55         if (!topology_enabled || !MACHINE_HAS_TOPOLOGY) {
  56                 cpumask_copy(&mask, cpumask_of(cpu));
  57                 return mask;
  58         }
  59         while (info) {
  60                 if (cpumask_test_cpu(cpu, &info->mask)) {
  61                         mask = info->mask;
  62                         break;
  63                 }
  64                 info = info->next;
  65         }
  66         if (cpumask_empty(&mask))
  67                 cpumask_copy(&mask, cpumask_of(cpu));
  68         return mask;
  69 }
  70
  71 static struct mask_info *add_cpus_to_mask(struct topology_cpu *tl_cpu,
  72                                           struct mask_info *book,
  73                                           struct mask_info *core,
  74                                           int one_core_per_cpu)
  75 {
  76         unsigned int cpu;
  77
  78         for (cpu = find_first_bit(&tl_cpu->mask[0], TOPOLOGY_CPU_BITS);
  79              cpu < TOPOLOGY_CPU_BITS;
  80              cpu = find_next_bit(&tl_cpu->mask[0], TOPOLOGY_CPU_BITS, cpu + 1))
  81         {
  82                 unsigned int rcpu;
  83                 int lcpu;
  84
  85                 rcpu = TOPOLOGY_CPU_BITS - 1 - cpu + tl_cpu->origin;
  86                 lcpu = smp_find_processor_id(rcpu);
  87                 if (lcpu >= 0) {
  88                         cpumask_set_cpu(lcpu, &book->mask);
  89                         cpu_book_id[lcpu] = book->id;
  90                         cpumask_set_cpu(lcpu, &core->mask);
  91                         if (one_core_per_cpu) {
  92                                 cpu_core_id[lcpu] = rcpu;
  93                                 core = core->next;
  94                         } else {
  95                                 cpu_core_id[lcpu] = core->id;
  96                         }
  97                         cpu_set_polarization(lcpu, tl_cpu->pp);
  98                 }
  99         }
 100         return core;
 101 }
 102
 103 static void clear_masks(void)
 104 {
 105         struct mask_info *info;
 106
 107         info = &core_info;
 108         while (info) {
 109                 cpumask_clear(&info->mask);
 110                 info = info->next;
 111         }
 112         info = &book_info;
 113         while (info) {
 114                 cpumask_clear(&info->mask);
 115                 info = info->next;
 116         }
 117 }
 118
 119 static union topology_entry *next_tle(union topology_entry *tle)
 120 {
 121         if (!tle->nl)
 122                 return (union topology_entry *)((struct topology_cpu *)tle + 1);
 123         return (union topology_entry *)((struct topology_container *)tle + 1);
 124 }
 125
 126 static void __tl_to_cores_generic(struct sysinfo_15_1_x *info)
 127 {
 128         struct mask_info *core = &core_info;
 129         struct mask_info *book = &book_info;
 130         union topology_entry *tle, *end;
 131
 132         tle = info->tle;
 133         end = (union topology_entry *)((unsigned long)info + info->length);
 134         while (tle < end) {
 135                 switch (tle->nl) {
 136                 case 2:
 137                         book = book->next;
 138                         book->id = tle->container.id;
 139                         break;
 140                 case 1:
 141                         core = core->next;
 142                         core->id = tle->container.id;
 143                         break;
 144                 case 0:
 145                         add_cpus_to_mask(&tle->cpu, book, core, 0);
 146                         break;
 147                 default:
 148                         clear_masks();
 149                         return;
 150                 }
 151                 tle = next_tle(tle);
 152         }
 153 }
 154
 155 static void __tl_to_cores_z10(struct sysinfo_15_1_x *info)
 156 {
 157         struct mask_info *core = &core_info;
 158         struct mask_info *book = &book_info;
 159         union topology_entry *tle, *end;
 160
 161         tle = info->tle;
 162         end = (union topology_entry *)((unsigned long)info + info->length);
 163         while (tle < end) {
 164                 switch (tle->nl) {
 165                 case 1:
 166                         book = book->next;
 167                         book->id = tle->container.id;
 168                         break;
 169                 case 0:
 170                         core = add_cpus_to_mask(&tle->cpu, book, core, 1);
 171                         break;
 172                 default:
 173                         clear_masks();
 174                         return;
 175                 }
 176                 tle = next_tle(tle);
 177         }
 178 }
 179
 180 static void tl_to_cores(struct sysinfo_15_1_x *info)
 181 {
 182         struct cpuid cpu_id;
 183
 184         get_cpu_id(&cpu_id);
 185         spin_lock_irq(&topology_lock);
 186         clear_masks();
 187         switch (cpu_id.machine) {
 188         case 0x2097:
 189         case 0x2098:
 190                 __tl_to_cores_z10(info);
 191                 break;
 192         default:
 193                 __tl_to_cores_generic(info);
 194         }
 195         spin_unlock_irq(&topology_lock);
 196 }
 197
 198 static void topology_update_polarization_simple(void)
 199 {
 200         int cpu;
 201
 202         mutex_lock(&smp_cpu_state_mutex);
 203         for_each_possible_cpu(cpu)
 204                 cpu_set_polarization(cpu, POLARIZATION_HRZ);
 205         mutex_unlock(&smp_cpu_state_mutex);
 206 }
 207
 208 static int ptf(unsigned long fc)
 209 {
 210         int rc;
 211
 212         asm volatile(
 213                 "       .insn   rre,0xb9a20000,%1,%1\n"
 214                 "       ipm     %0\n"
 215                 "       srl     %0,28\n"
 216                 : "=d" (rc)
 217                 : "d" (fc)  : "cc");
 218         return rc;
 219 }
 220
 221 int topology_set_cpu_management(int fc)
 222 {
 223         int cpu, rc;
 224
 225         if (!MACHINE_HAS_TOPOLOGY)
 226                 return -EOPNOTSUPP;
 227         if (fc)
 228                 rc = ptf(PTF_VERTICAL);
 229         else
 230                 rc = ptf(PTF_HORIZONTAL);
 231         if (rc)
 232                 return -EBUSY;
 233         for_each_possible_cpu(cpu)
 234                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 235         return rc;
 236 }
 237
 238 static void update_cpu_core_map(void)
 239 {
 240         unsigned long flags;
 241         int cpu;
 242
 243         spin_lock_irqsave(&topology_lock, flags);
 244         for_each_possible_cpu(cpu) {
 245                 cpu_core_map[cpu] = cpu_group_map(&core_info, cpu);
 246                 cpu_book_map[cpu] = cpu_group_map(&book_info, cpu);
 247         }
 248         spin_unlock_irqrestore(&topology_lock, flags);
 249 }
 250
 251 void store_topology(struct sysinfo_15_1_x *info)
 252 {
 253         int rc;
 254
 255         rc = stsi(info, 15, 1, 3);
 256         if (rc != -ENOSYS)
 257                 return;
 258         stsi(info, 15, 1, 2);
 259 }
 260
 261 int arch_update_cpu_topology(void)
 262 {
 263         struct sysinfo_15_1_x *info = tl_info;
 264         struct device *dev;
 265         int cpu;
 266
 267         if (!MACHINE_HAS_TOPOLOGY) {
 268                 update_cpu_core_map();
 269                 topology_update_polarization_simple();
 270                 return 0;
 271         }
 272         store_topology(info);
 273         tl_to_cores(info);
 274         update_cpu_core_map();
 275         for_each_online_cpu(cpu) {
 276                 dev = get_cpu_device(cpu);
 277                 kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 278         }
 279         return 1;
 280 }
 281
 282 static void topology_work_fn(struct work_struct *work)
 283 {
 284         rebuild_sched_domains();
 285 }
 286
 287 void topology_schedule_update(void)
 288 {
 289         schedule_work(&topology_work);
 290 }
 291
 292 static void topology_timer_fn(unsigned long ignored)
 293 {
 294         if (ptf(PTF_CHECK))
 295                 topology_schedule_update();
 296         set_topology_timer();
 297 }
 298
 299 static struct timer_list topology_timer =
 300         TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
 301
 302 static atomic_t topology_poll = ATOMIC_INIT(0);
 303
 304 static void set_topology_timer(void)
 305 {
 306         if (atomic_add_unless(&topology_poll, -1, 0))
 307                 mod_timer(&topology_timer, jiffies + HZ / 10);
 308         else
 309                 mod_timer(&topology_timer, jiffies + HZ * 60);
 310 }
 311
 312 void topology_expect_change(void)
 313 {
 314         if (!MACHINE_HAS_TOPOLOGY)
 315                 return;
 316         /* This is racy, but it doesn't matter since it is just a heuristic.
 317          * Worst case is that we poll in a higher frequency for a bit longer.
 318          */
 319         if (atomic_read(&topology_poll) > 60)
 320                 return;
 321         atomic_add(60, &topology_poll);
 322         set_topology_timer();
 323 }
 324
 325 static int __init early_parse_topology(char *p)
 326 {
 327         if (strncmp(p, "off", 3))
 328                 return 0;
 329         topology_enabled = 0;
 330         return 0;
 331 }
 332 early_param("topology", early_parse_topology);
 333
 334 static void __init alloc_masks(struct sysinfo_15_1_x *info,
 335                                struct mask_info *mask, int offset)
 336 {
 337         int i, nr_masks;
 338
 339         nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
 340         for (i = 0; i < info->mnest - offset; i++)
 341                 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
 342         nr_masks = max(nr_masks, 1);
 343         for (i = 0; i < nr_masks; i++) {
 344                 mask->next = alloc_bootmem(sizeof(struct mask_info));
 345                 mask = mask->next;
 346         }
 347 }
 348
 349 void __init s390_init_cpu_topology(void)
 350 {
 351         struct sysinfo_15_1_x *info;
 352         int i;
 353
 354         if (!MACHINE_HAS_TOPOLOGY)
 355                 return;
 356         tl_info = alloc_bootmem_pages(PAGE_SIZE);
 357         info = tl_info;
 358         store_topology(info);
 359         pr_info("The CPU configuration topology of the machine is:");
 360         for (i = 0; i < TOPOLOGY_NR_MAG; i++)
 361                 printk(KERN_CONT " %d", info->mag[i]);
 362         printk(KERN_CONT " / %d\n", info->mnest);
 363         alloc_masks(info, &core_info, 1);
 364         alloc_masks(info, &book_info, 2);
 365 }
 366
 367 static int cpu_management;
 368
 369 static ssize_t dispatching_show(struct device *dev,
 370                                 struct device_attribute *attr,
 371                                 char *buf)
 372 {
 373         ssize_t count;
 374
 375         mutex_lock(&smp_cpu_state_mutex);
 376         count = sprintf(buf, "%d\n", cpu_management);
 377         mutex_unlock(&smp_cpu_state_mutex);
 378         return count;
 379 }
 380
 381 static ssize_t dispatching_store(struct device *dev,
 382                                  struct device_attribute *attr,
 383                                  const char *buf,
 384                                  size_t count)
 385 {
 386         int val, rc;
 387         char delim;
 388
 389         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 390                 return -EINVAL;
 391         if (val != 0 && val != 1)
 392                 return -EINVAL;
 393         rc = 0;
 394         get_online_cpus();
 395         mutex_lock(&smp_cpu_state_mutex);
 396         if (cpu_management == val)
 397                 goto out;
 398         rc = topology_set_cpu_management(val);
 399         if (rc)
 400                 goto out;
 401         cpu_management = val;
 402         topology_expect_change();
 403 out:
 404         mutex_unlock(&smp_cpu_state_mutex);
 405         put_online_cpus();
 406         return rc ? rc : count;
 407 }
 408 static DEVICE_ATTR(dispatching, 0644, dispatching_show,
 409                          dispatching_store);
 410
 411 static ssize_t cpu_polarization_show(struct device *dev,
 412                                      struct device_attribute *attr, char *buf)
 413 {
 414         int cpu = dev->id;
 415         ssize_t count;
 416
 417         mutex_lock(&smp_cpu_state_mutex);
 418         switch (cpu_read_polarization(cpu)) {
 419         case POLARIZATION_HRZ:
 420                 count = sprintf(buf, "horizontal\n");
 421                 break;
 422         case POLARIZATION_VL:
 423                 count = sprintf(buf, "vertical:low\n");
 424                 break;
 425         case POLARIZATION_VM:
 426                 count = sprintf(buf, "vertical:medium\n");
 427                 break;
 428         case POLARIZATION_VH:
 429                 count = sprintf(buf, "vertical:high\n");
 430                 break;
 431         default:
 432                 count = sprintf(buf, "unknown\n");
 433                 break;
 434         }
 435         mutex_unlock(&smp_cpu_state_mutex);
 436         return count;
 437 }
 438 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 439
 440 static struct attribute *topology_cpu_attrs[] = {
 441         &dev_attr_polarization.attr,
 442         NULL,
 443 };
 444
 445 static struct attribute_group topology_cpu_attr_group = {
 446         .attrs = topology_cpu_attrs,
 447 };
 448
 449 int topology_cpu_init(struct cpu *cpu)
 450 {
 451         return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
 452 }
 453
 454 static int __init topology_init(void)
 455 {
 456         if (!MACHINE_HAS_TOPOLOGY) {
 457                 topology_update_polarization_simple();
 458                 goto out;
 459         }
 460         set_topology_timer();
 461 out:
 462         update_cpu_core_map();
 463         return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
 464 }
 465 device_initcall(topology_init);