arch/powerpc/kernel/sysfs.c

   1 #include <linux/sysdev.h>
   2 #include <linux/cpu.h>
   3 #include <linux/smp.h>
   4 #include <linux/percpu.h>
   5 #include <linux/init.h>
   6 #include <linux/sched.h>
   7 #include <linux/module.h>
   8 #include <linux/nodemask.h>
   9 #include <linux/cpumask.h>
  10 #include <linux/notifier.h>
  11
  12 #include <asm/current.h>
  13 #include <asm/processor.h>
  14 #include <asm/cputable.h>
  15 #include <asm/firmware.h>
  16 #include <asm/hvcall.h>
  17 #include <asm/prom.h>
  18 #include <asm/paca.h>
  19 #include <asm/lppaca.h>
  20 #include <asm/machdep.h>
  21 #include <asm/smp.h>
  22
  23 static DEFINE_PER_CPU(struct cpu, cpu_devices);
  24
  25 /* SMT stuff */
  26
  27 #ifdef CONFIG_PPC_MULTIPLATFORM
  28 /* Time in microseconds we delay before sleeping in the idle loop */
  29 DEFINE_PER_CPU(unsigned long, smt_snooze_delay) = { 100 };
  30
  31 static ssize_t store_smt_snooze_delay(struct sys_device *dev, const char *buf,
  32                                       size_t count)
  33 {
  34         struct cpu *cpu = container_of(dev, struct cpu, sysdev);
  35         ssize_t ret;
  36         unsigned long snooze;
  37
  38         ret = sscanf(buf, "%lu", &snooze);
  39         if (ret != 1)
  40                 return -EINVAL;
  41
  42         per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
  43
  44         return count;
  45 }
  46
  47 static ssize_t show_smt_snooze_delay(struct sys_device *dev, char *buf)
  48 {
  49         struct cpu *cpu = container_of(dev, struct cpu, sysdev);
  50
  51         return sprintf(buf, "%lu\n", per_cpu(smt_snooze_delay, cpu->sysdev.id));
  52 }
  53
  54 static SYSDEV_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
  55                    store_smt_snooze_delay);
  56
  57 /* Only parse OF options if the matching cmdline option was not specified */
  58 static int smt_snooze_cmdline;
  59
  60 static int __init smt_setup(void)
  61 {
  62         struct device_node *options;
  63         const unsigned int *val;
  64         unsigned int cpu;
  65
  66         if (!cpu_has_feature(CPU_FTR_SMT))
  67                 return -ENODEV;
  68
  69         options = of_find_node_by_path("/options");
  70         if (!options)
  71                 return -ENODEV;
  72
  73         val = of_get_property(options, "ibm,smt-snooze-delay", NULL);
  74         if (!smt_snooze_cmdline && val) {
  75                 for_each_possible_cpu(cpu)
  76                         per_cpu(smt_snooze_delay, cpu) = *val;
  77         }
  78
  79         of_node_put(options);
  80         return 0;
  81 }
  82 __initcall(smt_setup);
  83
  84 static int __init setup_smt_snooze_delay(char *str)
  85 {
  86         unsigned int cpu;
  87         int snooze;
  88
  89         if (!cpu_has_feature(CPU_FTR_SMT))
  90                 return 1;
  91
  92         smt_snooze_cmdline = 1;
  93
  94         if (get_option(&str, &snooze)) {
  95                 for_each_possible_cpu(cpu)
  96                         per_cpu(smt_snooze_delay, cpu) = snooze;
  97         }
  98
  99         return 1;
 100 }
 101 __setup("smt-snooze-delay=", setup_smt_snooze_delay);
 102
 103 #endif /* CONFIG_PPC_MULTIPLATFORM */
 104
 105 /*
 106  * Enabling PMCs will slow partition context switch times so we only do
 107  * it the first time we write to the PMCs.
 108  */
 109
 110 static DEFINE_PER_CPU(char, pmcs_enabled);
 111
 112 void ppc64_enable_pmcs(void)
 113 {
 114         /* Only need to enable them once */
 115         if (__get_cpu_var(pmcs_enabled))
 116                 return;
 117
 118         __get_cpu_var(pmcs_enabled) = 1;
 119
 120         if (ppc_md.enable_pmcs)
 121                 ppc_md.enable_pmcs();
 122 }
 123 EXPORT_SYMBOL(ppc64_enable_pmcs);
 124
 125 /* XXX convert to rusty's on_one_cpu */
 126 static unsigned long run_on_cpu(unsigned long cpu,
 127                                 unsigned long (*func)(unsigned long),
 128                                 unsigned long arg)
 129 {
 130         cpumask_t old_affinity = current->cpus_allowed;
 131         unsigned long ret;
 132
 133         /* should return -EINVAL to userspace */
 134         if (set_cpus_allowed(current, cpumask_of_cpu(cpu)))
 135                 return 0;
 136
 137         ret = func(arg);
 138
 139         set_cpus_allowed(current, old_affinity);
 140
 141         return ret;
 142 }
 143
 144 #define SYSFS_PMCSETUP(NAME, ADDRESS) \
 145 static unsigned long read_##NAME(unsigned long junk) \
 146 { \
 147         return mfspr(ADDRESS); \
 148 } \
 149 static unsigned long write_##NAME(unsigned long val) \
 150 { \
 151         ppc64_enable_pmcs(); \
 152         mtspr(ADDRESS, val); \
 153         return 0; \
 154 } \
 155 static ssize_t show_##NAME(struct sys_device *dev, char *buf) \
 156 { \
 157         struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
 158         unsigned long val = run_on_cpu(cpu->sysdev.id, read_##NAME, 0); \
 159         return sprintf(buf, "%lx\n", val); \
 160 } \
 161 static ssize_t __attribute_used__ \
 162         store_##NAME(struct sys_device *dev, const char *buf, size_t count) \
 163 { \
 164         struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
 165         unsigned long val; \
 166         int ret = sscanf(buf, "%lx", &val); \
 167         if (ret != 1) \
 168                 return -EINVAL; \
 169         run_on_cpu(cpu->sysdev.id, write_##NAME, val); \
 170         return count; \
 171 }
 172
 173
 174 /* Let's define all possible registers, we'll only hook up the ones
 175  * that are implemented on the current processor
 176  */
 177
 178 SYSFS_PMCSETUP(mmcr0, SPRN_MMCR0);
 179 SYSFS_PMCSETUP(mmcr1, SPRN_MMCR1);
 180 SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
 181 SYSFS_PMCSETUP(pmc1, SPRN_PMC1);
 182 SYSFS_PMCSETUP(pmc2, SPRN_PMC2);
 183 SYSFS_PMCSETUP(pmc3, SPRN_PMC3);
 184 SYSFS_PMCSETUP(pmc4, SPRN_PMC4);
 185 SYSFS_PMCSETUP(pmc5, SPRN_PMC5);
 186 SYSFS_PMCSETUP(pmc6, SPRN_PMC6);
 187 SYSFS_PMCSETUP(pmc7, SPRN_PMC7);
 188 SYSFS_PMCSETUP(pmc8, SPRN_PMC8);
 189 SYSFS_PMCSETUP(purr, SPRN_PURR);
 190 SYSFS_PMCSETUP(spurr, SPRN_SPURR);
 191 SYSFS_PMCSETUP(dscr, SPRN_DSCR);
 192
 193 SYSFS_PMCSETUP(pa6t_pmc0, SPRN_PA6T_PMC0);
 194 SYSFS_PMCSETUP(pa6t_pmc1, SPRN_PA6T_PMC1);
 195 SYSFS_PMCSETUP(pa6t_pmc2, SPRN_PA6T_PMC2);
 196 SYSFS_PMCSETUP(pa6t_pmc3, SPRN_PA6T_PMC3);
 197 SYSFS_PMCSETUP(pa6t_pmc4, SPRN_PA6T_PMC4);
 198 SYSFS_PMCSETUP(pa6t_pmc5, SPRN_PA6T_PMC5);
 199
 200 #ifdef CONFIG_DEBUG_KERNEL
 201 SYSFS_PMCSETUP(hid0, SPRN_HID0);
 202 SYSFS_PMCSETUP(hid1, SPRN_HID1);
 203 SYSFS_PMCSETUP(hid4, SPRN_HID4);
 204 SYSFS_PMCSETUP(hid5, SPRN_HID5);
 205 SYSFS_PMCSETUP(ima0, SPRN_PA6T_IMA0);
 206 SYSFS_PMCSETUP(ima1, SPRN_PA6T_IMA1);
 207 SYSFS_PMCSETUP(ima2, SPRN_PA6T_IMA2);
 208 SYSFS_PMCSETUP(ima3, SPRN_PA6T_IMA3);
 209 SYSFS_PMCSETUP(ima4, SPRN_PA6T_IMA4);
 210 SYSFS_PMCSETUP(ima5, SPRN_PA6T_IMA5);
 211 SYSFS_PMCSETUP(ima6, SPRN_PA6T_IMA6);
 212 SYSFS_PMCSETUP(ima7, SPRN_PA6T_IMA7);
 213 SYSFS_PMCSETUP(ima8, SPRN_PA6T_IMA8);
 214 SYSFS_PMCSETUP(ima9, SPRN_PA6T_IMA9);
 215 SYSFS_PMCSETUP(imaat, SPRN_PA6T_IMAAT);
 216 SYSFS_PMCSETUP(btcr, SPRN_PA6T_BTCR);
 217 SYSFS_PMCSETUP(pccr, SPRN_PA6T_PCCR);
 218 SYSFS_PMCSETUP(rpccr, SPRN_PA6T_RPCCR);
 219 SYSFS_PMCSETUP(der, SPRN_PA6T_DER);
 220 SYSFS_PMCSETUP(mer, SPRN_PA6T_MER);
 221 SYSFS_PMCSETUP(ber, SPRN_PA6T_BER);
 222 SYSFS_PMCSETUP(ier, SPRN_PA6T_IER);
 223 SYSFS_PMCSETUP(sier, SPRN_PA6T_SIER);
 224 SYSFS_PMCSETUP(siar, SPRN_PA6T_SIAR);
 225 SYSFS_PMCSETUP(tsr0, SPRN_PA6T_TSR0);
 226 SYSFS_PMCSETUP(tsr1, SPRN_PA6T_TSR1);
 227 SYSFS_PMCSETUP(tsr2, SPRN_PA6T_TSR2);
 228 SYSFS_PMCSETUP(tsr3, SPRN_PA6T_TSR3);
 229 #endif /* CONFIG_DEBUG_KERNEL */
 230
 231 static SYSDEV_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
 232 static SYSDEV_ATTR(spurr, 0600, show_spurr, NULL);
 233 static SYSDEV_ATTR(dscr, 0600, show_dscr, store_dscr);
 234 static SYSDEV_ATTR(purr, 0600, show_purr, store_purr);
 235
 236 static struct sysdev_attribute ibm_common_attrs[] = {
 237         _SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
 238         _SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
 239 };
 240
 241 static struct sysdev_attribute ibm_pmc_attrs[] = {
 242         _SYSDEV_ATTR(pmc1, 0600, show_pmc1, store_pmc1),
 243         _SYSDEV_ATTR(pmc2, 0600, show_pmc2, store_pmc2),
 244         _SYSDEV_ATTR(pmc3, 0600, show_pmc3, store_pmc3),
 245         _SYSDEV_ATTR(pmc4, 0600, show_pmc4, store_pmc4),
 246         _SYSDEV_ATTR(pmc5, 0600, show_pmc5, store_pmc5),
 247         _SYSDEV_ATTR(pmc6, 0600, show_pmc6, store_pmc6),
 248         _SYSDEV_ATTR(pmc7, 0600, show_pmc7, store_pmc7),
 249         _SYSDEV_ATTR(pmc8, 0600, show_pmc8, store_pmc8),
 250 };
 251
 252 static struct sysdev_attribute pa6t_attrs[] = {
 253         _SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
 254         _SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
 255         _SYSDEV_ATTR(pmc0, 0600, show_pa6t_pmc0, store_pa6t_pmc0),
 256         _SYSDEV_ATTR(pmc1, 0600, show_pa6t_pmc1, store_pa6t_pmc1),
 257         _SYSDEV_ATTR(pmc2, 0600, show_pa6t_pmc2, store_pa6t_pmc2),
 258         _SYSDEV_ATTR(pmc3, 0600, show_pa6t_pmc3, store_pa6t_pmc3),
 259         _SYSDEV_ATTR(pmc4, 0600, show_pa6t_pmc4, store_pa6t_pmc4),
 260         _SYSDEV_ATTR(pmc5, 0600, show_pa6t_pmc5, store_pa6t_pmc5),
 261 #ifdef CONFIG_DEBUG_KERNEL
 262         _SYSDEV_ATTR(hid0, 0600, show_hid0, store_hid0),
 263         _SYSDEV_ATTR(hid1, 0600, show_hid1, store_hid1),
 264         _SYSDEV_ATTR(hid4, 0600, show_hid4, store_hid4),
 265         _SYSDEV_ATTR(hid5, 0600, show_hid5, store_hid5),
 266         _SYSDEV_ATTR(ima0, 0600, show_ima0, store_ima0),
 267         _SYSDEV_ATTR(ima1, 0600, show_ima1, store_ima1),
 268         _SYSDEV_ATTR(ima2, 0600, show_ima2, store_ima2),
 269         _SYSDEV_ATTR(ima3, 0600, show_ima3, store_ima3),
 270         _SYSDEV_ATTR(ima4, 0600, show_ima4, store_ima4),
 271         _SYSDEV_ATTR(ima5, 0600, show_ima5, store_ima5),
 272         _SYSDEV_ATTR(ima6, 0600, show_ima6, store_ima6),
 273         _SYSDEV_ATTR(ima7, 0600, show_ima7, store_ima7),
 274         _SYSDEV_ATTR(ima8, 0600, show_ima8, store_ima8),
 275         _SYSDEV_ATTR(ima9, 0600, show_ima9, store_ima9),
 276         _SYSDEV_ATTR(imaat, 0600, show_imaat, store_imaat),
 277         _SYSDEV_ATTR(btcr, 0600, show_btcr, store_btcr),
 278         _SYSDEV_ATTR(pccr, 0600, show_pccr, store_pccr),
 279         _SYSDEV_ATTR(rpccr, 0600, show_rpccr, store_rpccr),
 280         _SYSDEV_ATTR(der, 0600, show_der, store_der),
 281         _SYSDEV_ATTR(mer, 0600, show_mer, store_mer),
 282         _SYSDEV_ATTR(ber, 0600, show_ber, store_ber),
 283         _SYSDEV_ATTR(ier, 0600, show_ier, store_ier),
 284         _SYSDEV_ATTR(sier, 0600, show_sier, store_sier),
 285         _SYSDEV_ATTR(siar, 0600, show_siar, store_siar),
 286         _SYSDEV_ATTR(tsr0, 0600, show_tsr0, store_tsr0),
 287         _SYSDEV_ATTR(tsr1, 0600, show_tsr1, store_tsr1),
 288         _SYSDEV_ATTR(tsr2, 0600, show_tsr2, store_tsr2),
 289         _SYSDEV_ATTR(tsr3, 0600, show_tsr3, store_tsr3),
 290 #endif /* CONFIG_DEBUG_KERNEL */
 291 };
 292
 293
 294 static void register_cpu_online(unsigned int cpu)
 295 {
 296         struct cpu *c = &per_cpu(cpu_devices, cpu);
 297         struct sys_device *s = &c->sysdev;
 298         struct sysdev_attribute *attrs, *pmc_attrs;
 299         int i, nattrs;
 300
 301         if (!firmware_has_feature(FW_FEATURE_ISERIES) &&
 302                         cpu_has_feature(CPU_FTR_SMT))
 303                 sysdev_create_file(s, &attr_smt_snooze_delay);
 304
 305         /* PMC stuff */
 306         switch (cur_cpu_spec->pmc_type) {
 307         case PPC_PMC_IBM:
 308                 attrs = ibm_common_attrs;
 309                 nattrs = sizeof(ibm_common_attrs) / sizeof(struct sysdev_attribute);
 310                 pmc_attrs = ibm_pmc_attrs;
 311                 break;
 312         case PPC_PMC_PA6T:
 313                 /* PA Semi starts counting at PMC0 */
 314                 attrs = pa6t_attrs;
 315                 nattrs = sizeof(pa6t_attrs) / sizeof(struct sysdev_attribute);
 316                 pmc_attrs = NULL;
 317                 break;
 318         default:
 319                 attrs = NULL;
 320                 nattrs = 0;
 321                 pmc_attrs = NULL;
 322         }
 323
 324         for (i = 0; i < nattrs; i++)
 325                 sysdev_create_file(s, &attrs[i]);
 326
 327         if (pmc_attrs)
 328                 for (i = 0; i < cur_cpu_spec->num_pmcs; i++)
 329                         sysdev_create_file(s, &pmc_attrs[i]);
 330
 331         if (cpu_has_feature(CPU_FTR_MMCRA))
 332                 sysdev_create_file(s, &attr_mmcra);
 333
 334         if (cpu_has_feature(CPU_FTR_PURR))
 335                 sysdev_create_file(s, &attr_purr);
 336
 337         if (cpu_has_feature(CPU_FTR_SPURR))
 338                 sysdev_create_file(s, &attr_spurr);
 339
 340         if (cpu_has_feature(CPU_FTR_DSCR))
 341                 sysdev_create_file(s, &attr_dscr);
 342 }
 343
 344 #ifdef CONFIG_HOTPLUG_CPU
 345 static void unregister_cpu_online(unsigned int cpu)
 346 {
 347         struct cpu *c = &per_cpu(cpu_devices, cpu);
 348         struct sys_device *s = &c->sysdev;
 349         struct sysdev_attribute *attrs, *pmc_attrs;
 350         int i, nattrs;
 351
 352         BUG_ON(!c->hotpluggable);
 353
 354         if (!firmware_has_feature(FW_FEATURE_ISERIES) &&
 355                         cpu_has_feature(CPU_FTR_SMT))
 356                 sysdev_remove_file(s, &attr_smt_snooze_delay);
 357
 358         /* PMC stuff */
 359         switch (cur_cpu_spec->pmc_type) {
 360         case PPC_PMC_IBM:
 361                 attrs = ibm_common_attrs;
 362                 nattrs = sizeof(ibm_common_attrs) / sizeof(struct sysdev_attribute);
 363                 pmc_attrs = ibm_pmc_attrs;
 364                 break;
 365         case PPC_PMC_PA6T:
 366                 /* PA Semi starts counting at PMC0 */
 367                 attrs = pa6t_attrs;
 368                 nattrs = sizeof(pa6t_attrs) / sizeof(struct sysdev_attribute);
 369                 pmc_attrs = NULL;
 370                 break;
 371         default:
 372                 attrs = NULL;
 373                 nattrs = 0;
 374                 pmc_attrs = NULL;
 375         }
 376
 377         for (i = 0; i < nattrs; i++)
 378                 sysdev_remove_file(s, &attrs[i]);
 379
 380         if (pmc_attrs)
 381                 for (i = 0; i < cur_cpu_spec->num_pmcs; i++)
 382                         sysdev_remove_file(s, &pmc_attrs[i]);
 383
 384         if (cpu_has_feature(CPU_FTR_MMCRA))
 385                 sysdev_remove_file(s, &attr_mmcra);
 386
 387         if (cpu_has_feature(CPU_FTR_PURR))
 388                 sysdev_remove_file(s, &attr_purr);
 389
 390         if (cpu_has_feature(CPU_FTR_SPURR))
 391                 sysdev_remove_file(s, &attr_spurr);
 392
 393         if (cpu_has_feature(CPU_FTR_DSCR))
 394                 sysdev_remove_file(s, &attr_dscr);
 395 }
 396 #endif /* CONFIG_HOTPLUG_CPU */
 397
 398 static int __cpuinit sysfs_cpu_notify(struct notifier_block *self,
 399                                       unsigned long action, void *hcpu)
 400 {
 401         unsigned int cpu = (unsigned int)(long)hcpu;
 402
 403         switch (action) {
 404         case CPU_ONLINE:
 405         case CPU_ONLINE_FROZEN:
 406                 register_cpu_online(cpu);
 407                 break;
 408 #ifdef CONFIG_HOTPLUG_CPU
 409         case CPU_DEAD:
 410         case CPU_DEAD_FROZEN:
 411                 unregister_cpu_online(cpu);
 412                 break;
 413 #endif
 414         }
 415         return NOTIFY_OK;
 416 }
 417
 418 static struct notifier_block __cpuinitdata sysfs_cpu_nb = {
 419         .notifier_call  = sysfs_cpu_notify,
 420 };
 421
 422 static DEFINE_MUTEX(cpu_mutex);
 423
 424 int cpu_add_sysdev_attr(struct sysdev_attribute *attr)
 425 {
 426         int cpu;
 427
 428         mutex_lock(&cpu_mutex);
 429
 430         for_each_possible_cpu(cpu) {
 431                 sysdev_create_file(get_cpu_sysdev(cpu), attr);
 432         }
 433
 434         mutex_unlock(&cpu_mutex);
 435         return 0;
 436 }
 437 EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr);
 438
 439 int cpu_add_sysdev_attr_group(struct attribute_group *attrs)
 440 {
 441         int cpu;
 442         struct sys_device *sysdev;
 443         int ret;
 444
 445         mutex_lock(&cpu_mutex);
 446
 447         for_each_possible_cpu(cpu) {
 448                 sysdev = get_cpu_sysdev(cpu);
 449                 ret = sysfs_create_group(&sysdev->kobj, attrs);
 450                 WARN_ON(ret != 0);
 451         }
 452
 453         mutex_unlock(&cpu_mutex);
 454         return 0;
 455 }
 456 EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr_group);
 457
 458
 459 void cpu_remove_sysdev_attr(struct sysdev_attribute *attr)
 460 {
 461         int cpu;
 462
 463         mutex_lock(&cpu_mutex);
 464
 465         for_each_possible_cpu(cpu) {
 466                 sysdev_remove_file(get_cpu_sysdev(cpu), attr);
 467         }
 468
 469         mutex_unlock(&cpu_mutex);
 470 }
 471 EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr);
 472
 473 void cpu_remove_sysdev_attr_group(struct attribute_group *attrs)
 474 {
 475         int cpu;
 476         struct sys_device *sysdev;
 477
 478         mutex_lock(&cpu_mutex);
 479
 480         for_each_possible_cpu(cpu) {
 481                 sysdev = get_cpu_sysdev(cpu);
 482                 sysfs_remove_group(&sysdev->kobj, attrs);
 483         }
 484
 485         mutex_unlock(&cpu_mutex);
 486 }
 487 EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr_group);
 488
 489
 490 /* NUMA stuff */
 491
 492 #ifdef CONFIG_NUMA
 493 static void register_nodes(void)
 494 {
 495         int i;
 496
 497         for (i = 0; i < MAX_NUMNODES; i++)
 498                 register_one_node(i);
 499 }
 500
 501 int sysfs_add_device_to_node(struct sys_device *dev, int nid)
 502 {
 503         struct node *node = &node_devices[nid];
 504         return sysfs_create_link(&node->sysdev.kobj, &dev->kobj,
 505                         kobject_name(&dev->kobj));
 506 }
 507 EXPORT_SYMBOL_GPL(sysfs_add_device_to_node);
 508
 509 void sysfs_remove_device_from_node(struct sys_device *dev, int nid)
 510 {
 511         struct node *node = &node_devices[nid];
 512         sysfs_remove_link(&node->sysdev.kobj, kobject_name(&dev->kobj));
 513 }
 514 EXPORT_SYMBOL_GPL(sysfs_remove_device_from_node);
 515
 516 #else
 517 static void register_nodes(void)
 518 {
 519         return;
 520 }
 521
 522 #endif
 523
 524 /* Only valid if CPU is present. */
 525 static ssize_t show_physical_id(struct sys_device *dev, char *buf)
 526 {
 527         struct cpu *cpu = container_of(dev, struct cpu, sysdev);
 528
 529         return sprintf(buf, "%d\n", get_hard_smp_processor_id(cpu->sysdev.id));
 530 }
 531 static SYSDEV_ATTR(physical_id, 0444, show_physical_id, NULL);
 532
 533 static int __init topology_init(void)
 534 {
 535         int cpu;
 536
 537         register_nodes();
 538         register_cpu_notifier(&sysfs_cpu_nb);
 539
 540         for_each_possible_cpu(cpu) {
 541                 struct cpu *c = &per_cpu(cpu_devices, cpu);
 542
 543                 /*
 544                  * For now, we just see if the system supports making
 545                  * the RTAS calls for CPU hotplug.  But, there may be a
 546                  * more comprehensive way to do this for an individual
 547                  * CPU.  For instance, the boot cpu might never be valid
 548                  * for hotplugging.
 549                  */
 550                 if (ppc_md.cpu_die)
 551                         c->hotpluggable = 1;
 552
 553                 if (cpu_online(cpu) || c->hotpluggable) {
 554                         register_cpu(c, cpu);
 555
 556                         sysdev_create_file(&c->sysdev, &attr_physical_id);
 557                 }
 558
 559                 if (cpu_online(cpu))
 560                         register_cpu_online(cpu);
 561         }
 562
 563         return 0;
 564 }
 565 subsys_initcall(topology_init);