git.oblomov.eu Git - linux-2.6/blob - 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,
  32                                       struct sysdev_attribute *attr,
  33                                       const char *buf,
  34                                       size_t count)
  35 {
  36         struct cpu *cpu = container_of(dev, struct cpu, sysdev);
  37         ssize_t ret;
  38         unsigned long snooze;
  39
  40         ret = sscanf(buf, "%lu", &snooze);
  41         if (ret != 1)
  42                 return -EINVAL;
  43
  44         per_cpu(smt_snooze_delay, cpu->sysdev.id) = snooze;
  45
  46         return count;
  47 }
  48
  49 static ssize_t show_smt_snooze_delay(struct sys_device *dev,
  50                                      struct sysdev_attribute *attr,
  51                                      char *buf)
  52 {
  53         struct cpu *cpu = container_of(dev, struct cpu, sysdev);
  54
  55         return sprintf(buf, "%lu\n", per_cpu(smt_snooze_delay, cpu->sysdev.id));
  56 }
  57
  58 static SYSDEV_ATTR(smt_snooze_delay, 0644, show_smt_snooze_delay,
  59                    store_smt_snooze_delay);
  60
  61 /* Only parse OF options if the matching cmdline option was not specified */
  62 static int smt_snooze_cmdline;
  63
  64 static int __init smt_setup(void)
  65 {
  66         struct device_node *options;
  67         const unsigned int *val;
  68         unsigned int cpu;
  69
  70         if (!cpu_has_feature(CPU_FTR_SMT))
  71                 return -ENODEV;
  72
  73         options = of_find_node_by_path("/options");
  74         if (!options)
  75                 return -ENODEV;
  76
  77         val = of_get_property(options, "ibm,smt-snooze-delay", NULL);
  78         if (!smt_snooze_cmdline && val) {
  79                 for_each_possible_cpu(cpu)
  80                         per_cpu(smt_snooze_delay, cpu) = *val;
  81         }
  82
  83         of_node_put(options);
  84         return 0;
  85 }
  86 __initcall(smt_setup);
  87
  88 static int __init setup_smt_snooze_delay(char *str)
  89 {
  90         unsigned int cpu;
  91         int snooze;
  92
  93         if (!cpu_has_feature(CPU_FTR_SMT))
  94                 return 1;
  95
  96         smt_snooze_cmdline = 1;
  97
  98         if (get_option(&str, &snooze)) {
  99                 for_each_possible_cpu(cpu)
 100                         per_cpu(smt_snooze_delay, cpu) = snooze;
 101         }
 102
 103         return 1;
 104 }
 105 __setup("smt-snooze-delay=", setup_smt_snooze_delay);
 106
 107 #endif /* CONFIG_PPC_MULTIPLATFORM */
 108
 109 /*
 110  * Enabling PMCs will slow partition context switch times so we only do
 111  * it the first time we write to the PMCs.
 112  */
 113
 114 static DEFINE_PER_CPU(char, pmcs_enabled);
 115
 116 void ppc64_enable_pmcs(void)
 117 {
 118         /* Only need to enable them once */
 119         if (__get_cpu_var(pmcs_enabled))
 120                 return;
 121
 122         __get_cpu_var(pmcs_enabled) = 1;
 123
 124         if (ppc_md.enable_pmcs)
 125                 ppc_md.enable_pmcs();
 126 }
 127 EXPORT_SYMBOL(ppc64_enable_pmcs);
 128
 129 /* XXX convert to rusty's on_one_cpu */
 130 static unsigned long run_on_cpu(unsigned long cpu,
 131                                 unsigned long (*func)(unsigned long),
 132                                 unsigned long arg)
 133 {
 134         cpumask_t old_affinity = current->cpus_allowed;
 135         unsigned long ret;
 136
 137         /* should return -EINVAL to userspace */
 138         if (set_cpus_allowed(current, cpumask_of_cpu(cpu)))
 139                 return 0;
 140
 141         ret = func(arg);
 142
 143         set_cpus_allowed(current, old_affinity);
 144
 145         return ret;
 146 }
 147
 148 #define SYSFS_PMCSETUP(NAME, ADDRESS) \
 149 static unsigned long read_##NAME(unsigned long junk) \
 150 { \
 151         return mfspr(ADDRESS); \
 152 } \
 153 static unsigned long write_##NAME(unsigned long val) \
 154 { \
 155         ppc64_enable_pmcs(); \
 156         mtspr(ADDRESS, val); \
 157         return 0; \
 158 } \
 159 static ssize_t show_##NAME(struct sys_device *dev, \
 160                         struct sysdev_attribute *attr, \
 161                         char *buf) \
 162 { \
 163         struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
 164         unsigned long val = run_on_cpu(cpu->sysdev.id, read_##NAME, 0); \
 165         return sprintf(buf, "%lx\n", val); \
 166 } \
 167 static ssize_t __used \
 168         store_##NAME(struct sys_device *dev, struct sysdev_attribute *attr, \
 169                         const char *buf, size_t count) \
 170 { \
 171         struct cpu *cpu = container_of(dev, struct cpu, sysdev); \
 172         unsigned long val; \
 173         int ret = sscanf(buf, "%lx", &val); \
 174         if (ret != 1) \
 175                 return -EINVAL; \
 176         run_on_cpu(cpu->sysdev.id, write_##NAME, val); \
 177         return count; \
 178 }
 179
 180
 181 /* Let's define all possible registers, we'll only hook up the ones
 182  * that are implemented on the current processor
 183  */
 184
 185 SYSFS_PMCSETUP(mmcr0, SPRN_MMCR0);
 186 SYSFS_PMCSETUP(mmcr1, SPRN_MMCR1);
 187 SYSFS_PMCSETUP(mmcra, SPRN_MMCRA);
 188 SYSFS_PMCSETUP(pmc1, SPRN_PMC1);
 189 SYSFS_PMCSETUP(pmc2, SPRN_PMC2);
 190 SYSFS_PMCSETUP(pmc3, SPRN_PMC3);
 191 SYSFS_PMCSETUP(pmc4, SPRN_PMC4);
 192 SYSFS_PMCSETUP(pmc5, SPRN_PMC5);
 193 SYSFS_PMCSETUP(pmc6, SPRN_PMC6);
 194 SYSFS_PMCSETUP(pmc7, SPRN_PMC7);
 195 SYSFS_PMCSETUP(pmc8, SPRN_PMC8);
 196 SYSFS_PMCSETUP(purr, SPRN_PURR);
 197 SYSFS_PMCSETUP(spurr, SPRN_SPURR);
 198 SYSFS_PMCSETUP(dscr, SPRN_DSCR);
 199
 200 SYSFS_PMCSETUP(pa6t_pmc0, SPRN_PA6T_PMC0);
 201 SYSFS_PMCSETUP(pa6t_pmc1, SPRN_PA6T_PMC1);
 202 SYSFS_PMCSETUP(pa6t_pmc2, SPRN_PA6T_PMC2);
 203 SYSFS_PMCSETUP(pa6t_pmc3, SPRN_PA6T_PMC3);
 204 SYSFS_PMCSETUP(pa6t_pmc4, SPRN_PA6T_PMC4);
 205 SYSFS_PMCSETUP(pa6t_pmc5, SPRN_PA6T_PMC5);
 206
 207 #ifdef CONFIG_DEBUG_KERNEL
 208 SYSFS_PMCSETUP(hid0, SPRN_HID0);
 209 SYSFS_PMCSETUP(hid1, SPRN_HID1);
 210 SYSFS_PMCSETUP(hid4, SPRN_HID4);
 211 SYSFS_PMCSETUP(hid5, SPRN_HID5);
 212 SYSFS_PMCSETUP(ima0, SPRN_PA6T_IMA0);
 213 SYSFS_PMCSETUP(ima1, SPRN_PA6T_IMA1);
 214 SYSFS_PMCSETUP(ima2, SPRN_PA6T_IMA2);
 215 SYSFS_PMCSETUP(ima3, SPRN_PA6T_IMA3);
 216 SYSFS_PMCSETUP(ima4, SPRN_PA6T_IMA4);
 217 SYSFS_PMCSETUP(ima5, SPRN_PA6T_IMA5);
 218 SYSFS_PMCSETUP(ima6, SPRN_PA6T_IMA6);
 219 SYSFS_PMCSETUP(ima7, SPRN_PA6T_IMA7);
 220 SYSFS_PMCSETUP(ima8, SPRN_PA6T_IMA8);
 221 SYSFS_PMCSETUP(ima9, SPRN_PA6T_IMA9);
 222 SYSFS_PMCSETUP(imaat, SPRN_PA6T_IMAAT);
 223 SYSFS_PMCSETUP(btcr, SPRN_PA6T_BTCR);
 224 SYSFS_PMCSETUP(pccr, SPRN_PA6T_PCCR);
 225 SYSFS_PMCSETUP(rpccr, SPRN_PA6T_RPCCR);
 226 SYSFS_PMCSETUP(der, SPRN_PA6T_DER);
 227 SYSFS_PMCSETUP(mer, SPRN_PA6T_MER);
 228 SYSFS_PMCSETUP(ber, SPRN_PA6T_BER);
 229 SYSFS_PMCSETUP(ier, SPRN_PA6T_IER);
 230 SYSFS_PMCSETUP(sier, SPRN_PA6T_SIER);
 231 SYSFS_PMCSETUP(siar, SPRN_PA6T_SIAR);
 232 SYSFS_PMCSETUP(tsr0, SPRN_PA6T_TSR0);
 233 SYSFS_PMCSETUP(tsr1, SPRN_PA6T_TSR1);
 234 SYSFS_PMCSETUP(tsr2, SPRN_PA6T_TSR2);
 235 SYSFS_PMCSETUP(tsr3, SPRN_PA6T_TSR3);
 236 #endif /* CONFIG_DEBUG_KERNEL */
 237
 238 static SYSDEV_ATTR(mmcra, 0600, show_mmcra, store_mmcra);
 239 static SYSDEV_ATTR(spurr, 0600, show_spurr, NULL);
 240 static SYSDEV_ATTR(dscr, 0600, show_dscr, store_dscr);
 241 static SYSDEV_ATTR(purr, 0600, show_purr, store_purr);
 242
 243 static struct sysdev_attribute ibm_common_attrs[] = {
 244         _SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
 245         _SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
 246 };
 247
 248 static struct sysdev_attribute ibm_pmc_attrs[] = {
 249         _SYSDEV_ATTR(pmc1, 0600, show_pmc1, store_pmc1),
 250         _SYSDEV_ATTR(pmc2, 0600, show_pmc2, store_pmc2),
 251         _SYSDEV_ATTR(pmc3, 0600, show_pmc3, store_pmc3),
 252         _SYSDEV_ATTR(pmc4, 0600, show_pmc4, store_pmc4),
 253         _SYSDEV_ATTR(pmc5, 0600, show_pmc5, store_pmc5),
 254         _SYSDEV_ATTR(pmc6, 0600, show_pmc6, store_pmc6),
 255         _SYSDEV_ATTR(pmc7, 0600, show_pmc7, store_pmc7),
 256         _SYSDEV_ATTR(pmc8, 0600, show_pmc8, store_pmc8),
 257 };
 258
 259 static struct sysdev_attribute pa6t_attrs[] = {
 260         _SYSDEV_ATTR(mmcr0, 0600, show_mmcr0, store_mmcr0),
 261         _SYSDEV_ATTR(mmcr1, 0600, show_mmcr1, store_mmcr1),
 262         _SYSDEV_ATTR(pmc0, 0600, show_pa6t_pmc0, store_pa6t_pmc0),
 263         _SYSDEV_ATTR(pmc1, 0600, show_pa6t_pmc1, store_pa6t_pmc1),
 264         _SYSDEV_ATTR(pmc2, 0600, show_pa6t_pmc2, store_pa6t_pmc2),
 265         _SYSDEV_ATTR(pmc3, 0600, show_pa6t_pmc3, store_pa6t_pmc3),
 266         _SYSDEV_ATTR(pmc4, 0600, show_pa6t_pmc4, store_pa6t_pmc4),
 267         _SYSDEV_ATTR(pmc5, 0600, show_pa6t_pmc5, store_pa6t_pmc5),
 268 #ifdef CONFIG_DEBUG_KERNEL
 269         _SYSDEV_ATTR(hid0, 0600, show_hid0, store_hid0),
 270         _SYSDEV_ATTR(hid1, 0600, show_hid1, store_hid1),
 271         _SYSDEV_ATTR(hid4, 0600, show_hid4, store_hid4),
 272         _SYSDEV_ATTR(hid5, 0600, show_hid5, store_hid5),
 273         _SYSDEV_ATTR(ima0, 0600, show_ima0, store_ima0),
 274         _SYSDEV_ATTR(ima1, 0600, show_ima1, store_ima1),
 275         _SYSDEV_ATTR(ima2, 0600, show_ima2, store_ima2),
 276         _SYSDEV_ATTR(ima3, 0600, show_ima3, store_ima3),
 277         _SYSDEV_ATTR(ima4, 0600, show_ima4, store_ima4),
 278         _SYSDEV_ATTR(ima5, 0600, show_ima5, store_ima5),
 279         _SYSDEV_ATTR(ima6, 0600, show_ima6, store_ima6),
 280         _SYSDEV_ATTR(ima7, 0600, show_ima7, store_ima7),
 281         _SYSDEV_ATTR(ima8, 0600, show_ima8, store_ima8),
 282         _SYSDEV_ATTR(ima9, 0600, show_ima9, store_ima9),
 283         _SYSDEV_ATTR(imaat, 0600, show_imaat, store_imaat),
 284         _SYSDEV_ATTR(btcr, 0600, show_btcr, store_btcr),
 285         _SYSDEV_ATTR(pccr, 0600, show_pccr, store_pccr),
 286         _SYSDEV_ATTR(rpccr, 0600, show_rpccr, store_rpccr),
 287         _SYSDEV_ATTR(der, 0600, show_der, store_der),
 288         _SYSDEV_ATTR(mer, 0600, show_mer, store_mer),
 289         _SYSDEV_ATTR(ber, 0600, show_ber, store_ber),
 290         _SYSDEV_ATTR(ier, 0600, show_ier, store_ier),
 291         _SYSDEV_ATTR(sier, 0600, show_sier, store_sier),
 292         _SYSDEV_ATTR(siar, 0600, show_siar, store_siar),
 293         _SYSDEV_ATTR(tsr0, 0600, show_tsr0, store_tsr0),
 294         _SYSDEV_ATTR(tsr1, 0600, show_tsr1, store_tsr1),
 295         _SYSDEV_ATTR(tsr2, 0600, show_tsr2, store_tsr2),
 296         _SYSDEV_ATTR(tsr3, 0600, show_tsr3, store_tsr3),
 297 #endif /* CONFIG_DEBUG_KERNEL */
 298 };
 299
 300
 301 static void register_cpu_online(unsigned int cpu)
 302 {
 303         struct cpu *c = &per_cpu(cpu_devices, cpu);
 304         struct sys_device *s = &c->sysdev;
 305         struct sysdev_attribute *attrs, *pmc_attrs;
 306         int i, nattrs;
 307
 308         if (!firmware_has_feature(FW_FEATURE_ISERIES) &&
 309                         cpu_has_feature(CPU_FTR_SMT))
 310                 sysdev_create_file(s, &attr_smt_snooze_delay);
 311
 312         /* PMC stuff */
 313         switch (cur_cpu_spec->pmc_type) {
 314         case PPC_PMC_IBM:
 315                 attrs = ibm_common_attrs;
 316                 nattrs = sizeof(ibm_common_attrs) / sizeof(struct sysdev_attribute);
 317                 pmc_attrs = ibm_pmc_attrs;
 318                 break;
 319         case PPC_PMC_PA6T:
 320                 /* PA Semi starts counting at PMC0 */
 321                 attrs = pa6t_attrs;
 322                 nattrs = sizeof(pa6t_attrs) / sizeof(struct sysdev_attribute);
 323                 pmc_attrs = NULL;
 324                 break;
 325         default:
 326                 attrs = NULL;
 327                 nattrs = 0;
 328                 pmc_attrs = NULL;
 329         }
 330
 331         for (i = 0; i < nattrs; i++)
 332                 sysdev_create_file(s, &attrs[i]);
 333
 334         if (pmc_attrs)
 335                 for (i = 0; i < cur_cpu_spec->num_pmcs; i++)
 336                         sysdev_create_file(s, &pmc_attrs[i]);
 337
 338         if (cpu_has_feature(CPU_FTR_MMCRA))
 339                 sysdev_create_file(s, &attr_mmcra);
 340
 341         if (cpu_has_feature(CPU_FTR_PURR))
 342                 sysdev_create_file(s, &attr_purr);
 343
 344         if (cpu_has_feature(CPU_FTR_SPURR))
 345                 sysdev_create_file(s, &attr_spurr);
 346
 347         if (cpu_has_feature(CPU_FTR_DSCR))
 348                 sysdev_create_file(s, &attr_dscr);
 349 }
 350
 351 #ifdef CONFIG_HOTPLUG_CPU
 352 static void unregister_cpu_online(unsigned int cpu)
 353 {
 354         struct cpu *c = &per_cpu(cpu_devices, cpu);
 355         struct sys_device *s = &c->sysdev;
 356         struct sysdev_attribute *attrs, *pmc_attrs;
 357         int i, nattrs;
 358
 359         BUG_ON(!c->hotpluggable);
 360
 361         if (!firmware_has_feature(FW_FEATURE_ISERIES) &&
 362                         cpu_has_feature(CPU_FTR_SMT))
 363                 sysdev_remove_file(s, &attr_smt_snooze_delay);
 364
 365         /* PMC stuff */
 366         switch (cur_cpu_spec->pmc_type) {
 367         case PPC_PMC_IBM:
 368                 attrs = ibm_common_attrs;
 369                 nattrs = sizeof(ibm_common_attrs) / sizeof(struct sysdev_attribute);
 370                 pmc_attrs = ibm_pmc_attrs;
 371                 break;
 372         case PPC_PMC_PA6T:
 373                 /* PA Semi starts counting at PMC0 */
 374                 attrs = pa6t_attrs;
 375                 nattrs = sizeof(pa6t_attrs) / sizeof(struct sysdev_attribute);
 376                 pmc_attrs = NULL;
 377                 break;
 378         default:
 379                 attrs = NULL;
 380                 nattrs = 0;
 381                 pmc_attrs = NULL;
 382         }
 383
 384         for (i = 0; i < nattrs; i++)
 385                 sysdev_remove_file(s, &attrs[i]);
 386
 387         if (pmc_attrs)
 388                 for (i = 0; i < cur_cpu_spec->num_pmcs; i++)
 389                         sysdev_remove_file(s, &pmc_attrs[i]);
 390
 391         if (cpu_has_feature(CPU_FTR_MMCRA))
 392                 sysdev_remove_file(s, &attr_mmcra);
 393
 394         if (cpu_has_feature(CPU_FTR_PURR))
 395                 sysdev_remove_file(s, &attr_purr);
 396
 397         if (cpu_has_feature(CPU_FTR_SPURR))
 398                 sysdev_remove_file(s, &attr_spurr);
 399
 400         if (cpu_has_feature(CPU_FTR_DSCR))
 401                 sysdev_remove_file(s, &attr_dscr);
 402 }
 403 #endif /* CONFIG_HOTPLUG_CPU */
 404
 405 static int __cpuinit sysfs_cpu_notify(struct notifier_block *self,
 406                                       unsigned long action, void *hcpu)
 407 {
 408         unsigned int cpu = (unsigned int)(long)hcpu;
 409
 410         switch (action) {
 411         case CPU_ONLINE:
 412         case CPU_ONLINE_FROZEN:
 413                 register_cpu_online(cpu);
 414                 break;
 415 #ifdef CONFIG_HOTPLUG_CPU
 416         case CPU_DEAD:
 417         case CPU_DEAD_FROZEN:
 418                 unregister_cpu_online(cpu);
 419                 break;
 420 #endif
 421         }
 422         return NOTIFY_OK;
 423 }
 424
 425 static struct notifier_block __cpuinitdata sysfs_cpu_nb = {
 426         .notifier_call  = sysfs_cpu_notify,
 427 };
 428
 429 static DEFINE_MUTEX(cpu_mutex);
 430
 431 int cpu_add_sysdev_attr(struct sysdev_attribute *attr)
 432 {
 433         int cpu;
 434
 435         mutex_lock(&cpu_mutex);
 436
 437         for_each_possible_cpu(cpu) {
 438                 sysdev_create_file(get_cpu_sysdev(cpu), attr);
 439         }
 440
 441         mutex_unlock(&cpu_mutex);
 442         return 0;
 443 }
 444 EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr);
 445
 446 int cpu_add_sysdev_attr_group(struct attribute_group *attrs)
 447 {
 448         int cpu;
 449         struct sys_device *sysdev;
 450         int ret;
 451
 452         mutex_lock(&cpu_mutex);
 453
 454         for_each_possible_cpu(cpu) {
 455                 sysdev = get_cpu_sysdev(cpu);
 456                 ret = sysfs_create_group(&sysdev->kobj, attrs);
 457                 WARN_ON(ret != 0);
 458         }
 459
 460         mutex_unlock(&cpu_mutex);
 461         return 0;
 462 }
 463 EXPORT_SYMBOL_GPL(cpu_add_sysdev_attr_group);
 464
 465
 466 void cpu_remove_sysdev_attr(struct sysdev_attribute *attr)
 467 {
 468         int cpu;
 469
 470         mutex_lock(&cpu_mutex);
 471
 472         for_each_possible_cpu(cpu) {
 473                 sysdev_remove_file(get_cpu_sysdev(cpu), attr);
 474         }
 475
 476         mutex_unlock(&cpu_mutex);
 477 }
 478 EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr);
 479
 480 void cpu_remove_sysdev_attr_group(struct attribute_group *attrs)
 481 {
 482         int cpu;
 483         struct sys_device *sysdev;
 484
 485         mutex_lock(&cpu_mutex);
 486
 487         for_each_possible_cpu(cpu) {
 488                 sysdev = get_cpu_sysdev(cpu);
 489                 sysfs_remove_group(&sysdev->kobj, attrs);
 490         }
 491
 492         mutex_unlock(&cpu_mutex);
 493 }
 494 EXPORT_SYMBOL_GPL(cpu_remove_sysdev_attr_group);
 495
 496
 497 /* NUMA stuff */
 498
 499 #ifdef CONFIG_NUMA
 500 static void register_nodes(void)
 501 {
 502         int i;
 503
 504         for (i = 0; i < MAX_NUMNODES; i++)
 505                 register_one_node(i);
 506 }
 507
 508 int sysfs_add_device_to_node(struct sys_device *dev, int nid)
 509 {
 510         struct node *node = &node_devices[nid];
 511         return sysfs_create_link(&node->sysdev.kobj, &dev->kobj,
 512                         kobject_name(&dev->kobj));
 513 }
 514 EXPORT_SYMBOL_GPL(sysfs_add_device_to_node);
 515
 516 void sysfs_remove_device_from_node(struct sys_device *dev, int nid)
 517 {
 518         struct node *node = &node_devices[nid];
 519         sysfs_remove_link(&node->sysdev.kobj, kobject_name(&dev->kobj));
 520 }
 521 EXPORT_SYMBOL_GPL(sysfs_remove_device_from_node);
 522
 523 #else
 524 static void register_nodes(void)
 525 {
 526         return;
 527 }
 528
 529 #endif
 530
 531 /* Only valid if CPU is present. */
 532 static ssize_t show_physical_id(struct sys_device *dev,
 533                                 struct sysdev_attribute *attr, char *buf)
 534 {
 535         struct cpu *cpu = container_of(dev, struct cpu, sysdev);
 536
 537         return sprintf(buf, "%d\n", get_hard_smp_processor_id(cpu->sysdev.id));
 538 }
 539 static SYSDEV_ATTR(physical_id, 0444, show_physical_id, NULL);
 540
 541 static int __init topology_init(void)
 542 {
 543         int cpu;
 544
 545         register_nodes();
 546         register_cpu_notifier(&sysfs_cpu_nb);
 547
 548         for_each_possible_cpu(cpu) {
 549                 struct cpu *c = &per_cpu(cpu_devices, cpu);
 550
 551                 /*
 552                  * For now, we just see if the system supports making
 553                  * the RTAS calls for CPU hotplug.  But, there may be a
 554                  * more comprehensive way to do this for an individual
 555                  * CPU.  For instance, the boot cpu might never be valid
 556                  * for hotplugging.
 557                  */
 558                 if (ppc_md.cpu_die)
 559                         c->hotpluggable = 1;
 560
 561                 if (cpu_online(cpu) || c->hotpluggable) {
 562                         register_cpu(c, cpu);
 563
 564                         sysdev_create_file(&c->sysdev, &attr_physical_id);
 565                 }
 566
 567                 if (cpu_online(cpu))
 568                         register_cpu_online(cpu);
 569         }
 570
 571         return 0;
 572 }
 573 subsys_initcall(topology_init);