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   1 /*
   2  *  arch/s390/kernel/smp.c
   3  *
   4  *    Copyright IBM Corp. 1999,2007
   5  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
   6  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   7  *               Heiko Carstens (heiko.carstens@de.ibm.com)
   8  *
   9  *  based on other smp stuff by
  10  *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
  11  *    (c) 1998 Ingo Molnar
  12  *
  13  * We work with logical cpu numbering everywhere we can. The only
  14  * functions using the real cpu address (got from STAP) are the sigp
  15  * functions. For all other functions we use the identity mapping.
  16  * That means that cpu_number_map[i] == i for every cpu. cpu_number_map is
  17  * used e.g. to find the idle task belonging to a logical cpu. Every array
  18  * in the kernel is sorted by the logical cpu number and not by the physical
  19  * one which is causing all the confusion with __cpu_logical_map and
  20  * cpu_number_map in other architectures.
  21  */
  22
  23 #define KMSG_COMPONENT "cpu"
  24 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  25
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28 #include <linux/mm.h>
  29 #include <linux/err.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/kernel_stat.h>
  32 #include <linux/delay.h>
  33 #include <linux/cache.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/irqflags.h>
  36 #include <linux/cpu.h>
  37 #include <linux/timex.h>
  38 #include <linux/bootmem.h>
  39 #include <asm/ipl.h>
  40 #include <asm/setup.h>
  41 #include <asm/sigp.h>
  42 #include <asm/pgalloc.h>
  43 #include <asm/irq.h>
  44 #include <asm/s390_ext.h>
  45 #include <asm/cpcmd.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/timer.h>
  48 #include <asm/lowcore.h>
  49 #include <asm/sclp.h>
  50 #include <asm/cpu.h>
  51 #include <asm/vdso.h>
  52 #include "entry.h"
  53
  54 static struct task_struct *current_set[NR_CPUS];
  55
  56 static u8 smp_cpu_type;
  57 static int smp_use_sigp_detection;
  58
  59 enum s390_cpu_state {
  60         CPU_STATE_STANDBY,
  61         CPU_STATE_CONFIGURED,
  62 };
  63
  64 DEFINE_MUTEX(smp_cpu_state_mutex);
  65 int smp_cpu_polarization[NR_CPUS];
  66 static int smp_cpu_state[NR_CPUS];
  67 static int cpu_management;
  68
  69 static DEFINE_PER_CPU(struct cpu, cpu_devices);
  70
  71 static void smp_ext_bitcall(int, ec_bit_sig);
  72
  73 void smp_send_stop(void)
  74 {
  75         int cpu, rc;
  76
  77         /* Disable all interrupts/machine checks */
  78         __load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
  79         trace_hardirqs_off();
  80
  81         /* stop all processors */
  82         for_each_online_cpu(cpu) {
  83                 if (cpu == smp_processor_id())
  84                         continue;
  85                 do {
  86                         rc = signal_processor(cpu, sigp_stop);
  87                 } while (rc == sigp_busy);
  88
  89                 while (!smp_cpu_not_running(cpu))
  90                         cpu_relax();
  91         }
  92 }
  93
  94 /*
  95  * This is the main routine where commands issued by other
  96  * cpus are handled.
  97  */
  98
  99 static void do_ext_call_interrupt(__u16 code)
 100 {
 101         unsigned long bits;
 102
 103         /*
 104          * handle bit signal external calls
 105          *
 106          * For the ec_schedule signal we have to do nothing. All the work
 107          * is done automatically when we return from the interrupt.
 108          */
 109         bits = xchg(&S390_lowcore.ext_call_fast, 0);
 110
 111         if (test_bit(ec_call_function, &bits))
 112                 generic_smp_call_function_interrupt();
 113
 114         if (test_bit(ec_call_function_single, &bits))
 115                 generic_smp_call_function_single_interrupt();
 116 }
 117
 118 /*
 119  * Send an external call sigp to another cpu and return without waiting
 120  * for its completion.
 121  */
 122 static void smp_ext_bitcall(int cpu, ec_bit_sig sig)
 123 {
 124         /*
 125          * Set signaling bit in lowcore of target cpu and kick it
 126          */
 127         set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
 128         while (signal_processor(cpu, sigp_emergency_signal) == sigp_busy)
 129                 udelay(10);
 130 }
 131
 132 void arch_send_call_function_ipi(cpumask_t mask)
 133 {
 134         int cpu;
 135
 136         for_each_cpu_mask(cpu, mask)
 137                 smp_ext_bitcall(cpu, ec_call_function);
 138 }
 139
 140 void arch_send_call_function_single_ipi(int cpu)
 141 {
 142         smp_ext_bitcall(cpu, ec_call_function_single);
 143 }
 144
 145 #ifndef CONFIG_64BIT
 146 /*
 147  * this function sends a 'purge tlb' signal to another CPU.
 148  */
 149 static void smp_ptlb_callback(void *info)
 150 {
 151         __tlb_flush_local();
 152 }
 153
 154 void smp_ptlb_all(void)
 155 {
 156         on_each_cpu(smp_ptlb_callback, NULL, 1);
 157 }
 158 EXPORT_SYMBOL(smp_ptlb_all);
 159 #endif /* ! CONFIG_64BIT */
 160
 161 /*
 162  * this function sends a 'reschedule' IPI to another CPU.
 163  * it goes straight through and wastes no time serializing
 164  * anything. Worst case is that we lose a reschedule ...
 165  */
 166 void smp_send_reschedule(int cpu)
 167 {
 168         smp_ext_bitcall(cpu, ec_schedule);
 169 }
 170
 171 /*
 172  * parameter area for the set/clear control bit callbacks
 173  */
 174 struct ec_creg_mask_parms {
 175         unsigned long orvals[16];
 176         unsigned long andvals[16];
 177 };
 178
 179 /*
 180  * callback for setting/clearing control bits
 181  */
 182 static void smp_ctl_bit_callback(void *info)
 183 {
 184         struct ec_creg_mask_parms *pp = info;
 185         unsigned long cregs[16];
 186         int i;
 187
 188         __ctl_store(cregs, 0, 15);
 189         for (i = 0; i <= 15; i++)
 190                 cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
 191         __ctl_load(cregs, 0, 15);
 192 }
 193
 194 /*
 195  * Set a bit in a control register of all cpus
 196  */
 197 void smp_ctl_set_bit(int cr, int bit)
 198 {
 199         struct ec_creg_mask_parms parms;
 200
 201         memset(&parms.orvals, 0, sizeof(parms.orvals));
 202         memset(&parms.andvals, 0xff, sizeof(parms.andvals));
 203         parms.orvals[cr] = 1 << bit;
 204         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 205 }
 206 EXPORT_SYMBOL(smp_ctl_set_bit);
 207
 208 /*
 209  * Clear a bit in a control register of all cpus
 210  */
 211 void smp_ctl_clear_bit(int cr, int bit)
 212 {
 213         struct ec_creg_mask_parms parms;
 214
 215         memset(&parms.orvals, 0, sizeof(parms.orvals));
 216         memset(&parms.andvals, 0xff, sizeof(parms.andvals));
 217         parms.andvals[cr] = ~(1L << bit);
 218         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 219 }
 220 EXPORT_SYMBOL(smp_ctl_clear_bit);
 221
 222 /*
 223  * In early ipl state a temp. logically cpu number is needed, so the sigp
 224  * functions can be used to sense other cpus. Since NR_CPUS is >= 2 on
 225  * CONFIG_SMP and the ipl cpu is logical cpu 0, it must be 1.
 226  */
 227 #define CPU_INIT_NO     1
 228
 229 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_ZFCPDUMP_MODULE)
 230
 231 /*
 232  * zfcpdump_prefix_array holds prefix registers for the following scenario:
 233  * 64 bit zfcpdump kernel and 31 bit kernel which is to be dumped. We have to
 234  * save its prefix registers, since they get lost, when switching from 31 bit
 235  * to 64 bit.
 236  */
 237 unsigned int zfcpdump_prefix_array[NR_CPUS + 1] \
 238         __attribute__((__section__(".data")));
 239
 240 static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
 241 {
 242         if (ipl_info.type != IPL_TYPE_FCP_DUMP)
 243                 return;
 244         if (cpu >= NR_CPUS) {
 245                 pr_warning("CPU %i exceeds the maximum %i and is excluded from "
 246                            "the dump\n", cpu, NR_CPUS - 1);
 247                 return;
 248         }
 249         zfcpdump_save_areas[cpu] = kmalloc(sizeof(union save_area), GFP_KERNEL);
 250         __cpu_logical_map[CPU_INIT_NO] = (__u16) phy_cpu;
 251         while (signal_processor(CPU_INIT_NO, sigp_stop_and_store_status) ==
 252                sigp_busy)
 253                 cpu_relax();
 254         memcpy(zfcpdump_save_areas[cpu],
 255                (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
 256                SAVE_AREA_SIZE);
 257 #ifdef CONFIG_64BIT
 258         /* copy original prefix register */
 259         zfcpdump_save_areas[cpu]->s390x.pref_reg = zfcpdump_prefix_array[cpu];
 260 #endif
 261 }
 262
 263 union save_area *zfcpdump_save_areas[NR_CPUS + 1];
 264 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
 265
 266 #else
 267
 268 static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }
 269
 270 #endif /* CONFIG_ZFCPDUMP || CONFIG_ZFCPDUMP_MODULE */
 271
 272 static int cpu_stopped(int cpu)
 273 {
 274         __u32 status;
 275
 276         /* Check for stopped state */
 277         if (signal_processor_ps(&status, 0, cpu, sigp_sense) ==
 278             sigp_status_stored) {
 279                 if (status & 0x40)
 280                         return 1;
 281         }
 282         return 0;
 283 }
 284
 285 static int cpu_known(int cpu_id)
 286 {
 287         int cpu;
 288
 289         for_each_present_cpu(cpu) {
 290                 if (__cpu_logical_map[cpu] == cpu_id)
 291                         return 1;
 292         }
 293         return 0;
 294 }
 295
 296 static int smp_rescan_cpus_sigp(cpumask_t avail)
 297 {
 298         int cpu_id, logical_cpu;
 299
 300         logical_cpu = first_cpu(avail);
 301         if (logical_cpu == NR_CPUS)
 302                 return 0;
 303         for (cpu_id = 0; cpu_id <= 65535; cpu_id++) {
 304                 if (cpu_known(cpu_id))
 305                         continue;
 306                 __cpu_logical_map[logical_cpu] = cpu_id;
 307                 smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
 308                 if (!cpu_stopped(logical_cpu))
 309                         continue;
 310                 cpu_set(logical_cpu, cpu_present_map);
 311                 smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
 312                 logical_cpu = next_cpu(logical_cpu, avail);
 313                 if (logical_cpu == NR_CPUS)
 314                         break;
 315         }
 316         return 0;
 317 }
 318
 319 static int smp_rescan_cpus_sclp(cpumask_t avail)
 320 {
 321         struct sclp_cpu_info *info;
 322         int cpu_id, logical_cpu, cpu;
 323         int rc;
 324
 325         logical_cpu = first_cpu(avail);
 326         if (logical_cpu == NR_CPUS)
 327                 return 0;
 328         info = kmalloc(sizeof(*info), GFP_KERNEL);
 329         if (!info)
 330                 return -ENOMEM;
 331         rc = sclp_get_cpu_info(info);
 332         if (rc)
 333                 goto out;
 334         for (cpu = 0; cpu < info->combined; cpu++) {
 335                 if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
 336                         continue;
 337                 cpu_id = info->cpu[cpu].address;
 338                 if (cpu_known(cpu_id))
 339                         continue;
 340                 __cpu_logical_map[logical_cpu] = cpu_id;
 341                 smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
 342                 cpu_set(logical_cpu, cpu_present_map);
 343                 if (cpu >= info->configured)
 344                         smp_cpu_state[logical_cpu] = CPU_STATE_STANDBY;
 345                 else
 346                         smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
 347                 logical_cpu = next_cpu(logical_cpu, avail);
 348                 if (logical_cpu == NR_CPUS)
 349                         break;
 350         }
 351 out:
 352         kfree(info);
 353         return rc;
 354 }
 355
 356 static int __smp_rescan_cpus(void)
 357 {
 358         cpumask_t avail;
 359
 360         cpus_xor(avail, cpu_possible_map, cpu_present_map);
 361         if (smp_use_sigp_detection)
 362                 return smp_rescan_cpus_sigp(avail);
 363         else
 364                 return smp_rescan_cpus_sclp(avail);
 365 }
 366
 367 static void __init smp_detect_cpus(void)
 368 {
 369         unsigned int cpu, c_cpus, s_cpus;
 370         struct sclp_cpu_info *info;
 371         u16 boot_cpu_addr, cpu_addr;
 372
 373         c_cpus = 1;
 374         s_cpus = 0;
 375         boot_cpu_addr = __cpu_logical_map[0];
 376         info = kmalloc(sizeof(*info), GFP_KERNEL);
 377         if (!info)
 378                 panic("smp_detect_cpus failed to allocate memory\n");
 379         /* Use sigp detection algorithm if sclp doesn't work. */
 380         if (sclp_get_cpu_info(info)) {
 381                 smp_use_sigp_detection = 1;
 382                 for (cpu = 0; cpu <= 65535; cpu++) {
 383                         if (cpu == boot_cpu_addr)
 384                                 continue;
 385                         __cpu_logical_map[CPU_INIT_NO] = cpu;
 386                         if (!cpu_stopped(CPU_INIT_NO))
 387                                 continue;
 388                         smp_get_save_area(c_cpus, cpu);
 389                         c_cpus++;
 390                 }
 391                 goto out;
 392         }
 393
 394         if (info->has_cpu_type) {
 395                 for (cpu = 0; cpu < info->combined; cpu++) {
 396                         if (info->cpu[cpu].address == boot_cpu_addr) {
 397                                 smp_cpu_type = info->cpu[cpu].type;
 398                                 break;
 399                         }
 400                 }
 401         }
 402
 403         for (cpu = 0; cpu < info->combined; cpu++) {
 404                 if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
 405                         continue;
 406                 cpu_addr = info->cpu[cpu].address;
 407                 if (cpu_addr == boot_cpu_addr)
 408                         continue;
 409                 __cpu_logical_map[CPU_INIT_NO] = cpu_addr;
 410                 if (!cpu_stopped(CPU_INIT_NO)) {
 411                         s_cpus++;
 412                         continue;
 413                 }
 414                 smp_get_save_area(c_cpus, cpu_addr);
 415                 c_cpus++;
 416         }
 417 out:
 418         kfree(info);
 419         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 420         get_online_cpus();
 421         __smp_rescan_cpus();
 422         put_online_cpus();
 423 }
 424
 425 /*
 426  *      Activate a secondary processor.
 427  */
 428 int __cpuinit start_secondary(void *cpuvoid)
 429 {
 430         /* Setup the cpu */
 431         cpu_init();
 432         preempt_disable();
 433         /* Enable TOD clock interrupts on the secondary cpu. */
 434         init_cpu_timer();
 435         /* Enable cpu timer interrupts on the secondary cpu. */
 436         init_cpu_vtimer();
 437         /* Enable pfault pseudo page faults on this cpu. */
 438         pfault_init();
 439
 440         /* call cpu notifiers */
 441         notify_cpu_starting(smp_processor_id());
 442         /* Mark this cpu as online */
 443         ipi_call_lock();
 444         cpu_set(smp_processor_id(), cpu_online_map);
 445         ipi_call_unlock();
 446         /* Switch on interrupts */
 447         local_irq_enable();
 448         /* Print info about this processor */
 449         print_cpu_info();
 450         /* cpu_idle will call schedule for us */
 451         cpu_idle();
 452         return 0;
 453 }
 454
 455 static void __init smp_create_idle(unsigned int cpu)
 456 {
 457         struct task_struct *p;
 458
 459         /*
 460          *  don't care about the psw and regs settings since we'll never
 461          *  reschedule the forked task.
 462          */
 463         p = fork_idle(cpu);
 464         if (IS_ERR(p))
 465                 panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
 466         current_set[cpu] = p;
 467 }
 468
 469 static int __cpuinit smp_alloc_lowcore(int cpu)
 470 {
 471         unsigned long async_stack, panic_stack;
 472         struct _lowcore *lowcore;
 473         int lc_order;
 474
 475         lc_order = sizeof(long) == 8 ? 1 : 0;
 476         lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
 477         if (!lowcore)
 478                 return -ENOMEM;
 479         async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 480         panic_stack = __get_free_page(GFP_KERNEL);
 481         if (!panic_stack || !async_stack)
 482                 goto out;
 483         memcpy(lowcore, &S390_lowcore, 512);
 484         memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
 485         lowcore->async_stack = async_stack + ASYNC_SIZE;
 486         lowcore->panic_stack = panic_stack + PAGE_SIZE;
 487
 488 #ifndef CONFIG_64BIT
 489         if (MACHINE_HAS_IEEE) {
 490                 unsigned long save_area;
 491
 492                 save_area = get_zeroed_page(GFP_KERNEL);
 493                 if (!save_area)
 494                         goto out;
 495                 lowcore->extended_save_area_addr = (u32) save_area;
 496         }
 497 #else
 498         if (vdso_alloc_per_cpu(cpu, lowcore))
 499                 goto out;
 500 #endif
 501         lowcore_ptr[cpu] = lowcore;
 502         return 0;
 503
 504 out:
 505         free_page(panic_stack);
 506         free_pages(async_stack, ASYNC_ORDER);
 507         free_pages((unsigned long) lowcore, lc_order);
 508         return -ENOMEM;
 509 }
 510
 511 #ifdef CONFIG_HOTPLUG_CPU
 512 static void smp_free_lowcore(int cpu)
 513 {
 514         struct _lowcore *lowcore;
 515         int lc_order;
 516
 517         lc_order = sizeof(long) == 8 ? 1 : 0;
 518         lowcore = lowcore_ptr[cpu];
 519 #ifndef CONFIG_64BIT
 520         if (MACHINE_HAS_IEEE)
 521                 free_page((unsigned long) lowcore->extended_save_area_addr);
 522 #else
 523         vdso_free_per_cpu(cpu, lowcore);
 524 #endif
 525         free_page(lowcore->panic_stack - PAGE_SIZE);
 526         free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
 527         free_pages((unsigned long) lowcore, lc_order);
 528         lowcore_ptr[cpu] = NULL;
 529 }
 530 #endif /* CONFIG_HOTPLUG_CPU */
 531
 532 /* Upping and downing of CPUs */
 533 int __cpuinit __cpu_up(unsigned int cpu)
 534 {
 535         struct task_struct *idle;
 536         struct _lowcore *cpu_lowcore;
 537         struct stack_frame *sf;
 538         sigp_ccode ccode;
 539
 540         if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
 541                 return -EIO;
 542         if (smp_alloc_lowcore(cpu))
 543                 return -ENOMEM;
 544
 545         ccode = signal_processor_p((__u32)(unsigned long)(lowcore_ptr[cpu]),
 546                                    cpu, sigp_set_prefix);
 547         if (ccode)
 548                 return -EIO;
 549
 550         idle = current_set[cpu];
 551         cpu_lowcore = lowcore_ptr[cpu];
 552         cpu_lowcore->kernel_stack = (unsigned long)
 553                 task_stack_page(idle) + THREAD_SIZE;
 554         cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
 555         sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
 556                                      - sizeof(struct pt_regs)
 557                                      - sizeof(struct stack_frame));
 558         memset(sf, 0, sizeof(struct stack_frame));
 559         sf->gprs[9] = (unsigned long) sf;
 560         cpu_lowcore->save_area[15] = (unsigned long) sf;
 561         __ctl_store(cpu_lowcore->cregs_save_area, 0, 15);
 562         asm volatile(
 563                 "       stam    0,15,0(%0)"
 564                 : : "a" (&cpu_lowcore->access_regs_save_area) : "memory");
 565         cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
 566         cpu_lowcore->current_task = (unsigned long) idle;
 567         cpu_lowcore->cpu_nr = cpu;
 568         cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
 569         cpu_lowcore->ipl_device = S390_lowcore.ipl_device;
 570         eieio();
 571
 572         while (signal_processor(cpu, sigp_restart) == sigp_busy)
 573                 udelay(10);
 574
 575         while (!cpu_online(cpu))
 576                 cpu_relax();
 577         return 0;
 578 }
 579
 580 static int __init setup_possible_cpus(char *s)
 581 {
 582         int pcpus, cpu;
 583
 584         pcpus = simple_strtoul(s, NULL, 0);
 585         cpu_possible_map = cpumask_of_cpu(0);
 586         for (cpu = 1; cpu < pcpus && cpu < NR_CPUS; cpu++)
 587                 cpu_set(cpu, cpu_possible_map);
 588         return 0;
 589 }
 590 early_param("possible_cpus", setup_possible_cpus);
 591
 592 #ifdef CONFIG_HOTPLUG_CPU
 593
 594 int __cpu_disable(void)
 595 {
 596         struct ec_creg_mask_parms cr_parms;
 597         int cpu = smp_processor_id();
 598
 599         cpu_clear(cpu, cpu_online_map);
 600
 601         /* Disable pfault pseudo page faults on this cpu. */
 602         pfault_fini();
 603
 604         memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));
 605         memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));
 606
 607         /* disable all external interrupts */
 608         cr_parms.orvals[0] = 0;
 609         cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 12 |
 610                                 1 << 11 | 1 << 10 | 1 <<  6 | 1 <<  4);
 611         /* disable all I/O interrupts */
 612         cr_parms.orvals[6] = 0;
 613         cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |
 614                                 1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);
 615         /* disable most machine checks */
 616         cr_parms.orvals[14] = 0;
 617         cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |
 618                                  1 << 25 | 1 << 24);
 619
 620         smp_ctl_bit_callback(&cr_parms);
 621
 622         return 0;
 623 }
 624
 625 void __cpu_die(unsigned int cpu)
 626 {
 627         /* Wait until target cpu is down */
 628         while (!smp_cpu_not_running(cpu))
 629                 cpu_relax();
 630         smp_free_lowcore(cpu);
 631         pr_info("Processor %d stopped\n", cpu);
 632 }
 633
 634 void cpu_die(void)
 635 {
 636         idle_task_exit();
 637         signal_processor(smp_processor_id(), sigp_stop);
 638         BUG();
 639         for (;;);
 640 }
 641
 642 #endif /* CONFIG_HOTPLUG_CPU */
 643
 644 void __init smp_prepare_cpus(unsigned int max_cpus)
 645 {
 646 #ifndef CONFIG_64BIT
 647         unsigned long save_area = 0;
 648 #endif
 649         unsigned long async_stack, panic_stack;
 650         struct _lowcore *lowcore;
 651         unsigned int cpu;
 652         int lc_order;
 653
 654         smp_detect_cpus();
 655
 656         /* request the 0x1201 emergency signal external interrupt */
 657         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
 658                 panic("Couldn't request external interrupt 0x1201");
 659         print_cpu_info();
 660
 661         /* Reallocate current lowcore, but keep its contents. */
 662         lc_order = sizeof(long) == 8 ? 1 : 0;
 663         lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, lc_order);
 664         panic_stack = __get_free_page(GFP_KERNEL);
 665         async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 666         BUG_ON(!lowcore || !panic_stack || !async_stack);
 667 #ifndef CONFIG_64BIT
 668         if (MACHINE_HAS_IEEE)
 669                 save_area = get_zeroed_page(GFP_KERNEL);
 670 #endif
 671         local_irq_disable();
 672         local_mcck_disable();
 673         lowcore_ptr[smp_processor_id()] = lowcore;
 674         *lowcore = S390_lowcore;
 675         lowcore->panic_stack = panic_stack + PAGE_SIZE;
 676         lowcore->async_stack = async_stack + ASYNC_SIZE;
 677 #ifndef CONFIG_64BIT
 678         if (MACHINE_HAS_IEEE)
 679                 lowcore->extended_save_area_addr = (u32) save_area;
 680 #else
 681         if (vdso_alloc_per_cpu(smp_processor_id(), lowcore))
 682                 BUG();
 683 #endif
 684         set_prefix((u32)(unsigned long) lowcore);
 685         local_mcck_enable();
 686         local_irq_enable();
 687         for_each_possible_cpu(cpu)
 688                 if (cpu != smp_processor_id())
 689                         smp_create_idle(cpu);
 690 }
 691
 692 void __init smp_prepare_boot_cpu(void)
 693 {
 694         BUG_ON(smp_processor_id() != 0);
 695
 696         current_thread_info()->cpu = 0;
 697         cpu_set(0, cpu_present_map);
 698         cpu_set(0, cpu_online_map);
 699         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 700         current_set[0] = current;
 701         smp_cpu_state[0] = CPU_STATE_CONFIGURED;
 702         smp_cpu_polarization[0] = POLARIZATION_UNKNWN;
 703 }
 704
 705 void __init smp_cpus_done(unsigned int max_cpus)
 706 {
 707 }
 708
 709 /*
 710  * the frequency of the profiling timer can be changed
 711  * by writing a multiplier value into /proc/profile.
 712  *
 713  * usually you want to run this on all CPUs ;)
 714  */
 715 int setup_profiling_timer(unsigned int multiplier)
 716 {
 717         return 0;
 718 }
 719
 720 #ifdef CONFIG_HOTPLUG_CPU
 721 static ssize_t cpu_configure_show(struct sys_device *dev,
 722                                 struct sysdev_attribute *attr, char *buf)
 723 {
 724         ssize_t count;
 725
 726         mutex_lock(&smp_cpu_state_mutex);
 727         count = sprintf(buf, "%d\n", smp_cpu_state[dev->id]);
 728         mutex_unlock(&smp_cpu_state_mutex);
 729         return count;
 730 }
 731
 732 static ssize_t cpu_configure_store(struct sys_device *dev,
 733                                   struct sysdev_attribute *attr,
 734                                   const char *buf, size_t count)
 735 {
 736         int cpu = dev->id;
 737         int val, rc;
 738         char delim;
 739
 740         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 741                 return -EINVAL;
 742         if (val != 0 && val != 1)
 743                 return -EINVAL;
 744
 745         get_online_cpus();
 746         mutex_lock(&smp_cpu_state_mutex);
 747         rc = -EBUSY;
 748         if (cpu_online(cpu))
 749                 goto out;
 750         rc = 0;
 751         switch (val) {
 752         case 0:
 753                 if (smp_cpu_state[cpu] == CPU_STATE_CONFIGURED) {
 754                         rc = sclp_cpu_deconfigure(__cpu_logical_map[cpu]);
 755                         if (!rc) {
 756                                 smp_cpu_state[cpu] = CPU_STATE_STANDBY;
 757                                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
 758                         }
 759                 }
 760                 break;
 761         case 1:
 762                 if (smp_cpu_state[cpu] == CPU_STATE_STANDBY) {
 763                         rc = sclp_cpu_configure(__cpu_logical_map[cpu]);
 764                         if (!rc) {
 765                                 smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
 766                                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
 767                         }
 768                 }
 769                 break;
 770         default:
 771                 break;
 772         }
 773 out:
 774         mutex_unlock(&smp_cpu_state_mutex);
 775         put_online_cpus();
 776         return rc ? rc : count;
 777 }
 778 static SYSDEV_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
 779 #endif /* CONFIG_HOTPLUG_CPU */
 780
 781 static ssize_t cpu_polarization_show(struct sys_device *dev,
 782                                      struct sysdev_attribute *attr, char *buf)
 783 {
 784         int cpu = dev->id;
 785         ssize_t count;
 786
 787         mutex_lock(&smp_cpu_state_mutex);
 788         switch (smp_cpu_polarization[cpu]) {
 789         case POLARIZATION_HRZ:
 790                 count = sprintf(buf, "horizontal\n");
 791                 break;
 792         case POLARIZATION_VL:
 793                 count = sprintf(buf, "vertical:low\n");
 794                 break;
 795         case POLARIZATION_VM:
 796                 count = sprintf(buf, "vertical:medium\n");
 797                 break;
 798         case POLARIZATION_VH:
 799                 count = sprintf(buf, "vertical:high\n");
 800                 break;
 801         default:
 802                 count = sprintf(buf, "unknown\n");
 803                 break;
 804         }
 805         mutex_unlock(&smp_cpu_state_mutex);
 806         return count;
 807 }
 808 static SYSDEV_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 809
 810 static ssize_t show_cpu_address(struct sys_device *dev,
 811                                 struct sysdev_attribute *attr, char *buf)
 812 {
 813         return sprintf(buf, "%d\n", __cpu_logical_map[dev->id]);
 814 }
 815 static SYSDEV_ATTR(address, 0444, show_cpu_address, NULL);
 816
 817
 818 static struct attribute *cpu_common_attrs[] = {
 819 #ifdef CONFIG_HOTPLUG_CPU
 820         &attr_configure.attr,
 821 #endif
 822         &attr_address.attr,
 823         &attr_polarization.attr,
 824         NULL,
 825 };
 826
 827 static struct attribute_group cpu_common_attr_group = {
 828         .attrs = cpu_common_attrs,
 829 };
 830
 831 static ssize_t show_capability(struct sys_device *dev,
 832                                 struct sysdev_attribute *attr, char *buf)
 833 {
 834         unsigned int capability;
 835         int rc;
 836
 837         rc = get_cpu_capability(&capability);
 838         if (rc)
 839                 return rc;
 840         return sprintf(buf, "%u\n", capability);
 841 }
 842 static SYSDEV_ATTR(capability, 0444, show_capability, NULL);
 843
 844 static ssize_t show_idle_count(struct sys_device *dev,
 845                                 struct sysdev_attribute *attr, char *buf)
 846 {
 847         struct s390_idle_data *idle;
 848         unsigned long long idle_count;
 849
 850         idle = &per_cpu(s390_idle, dev->id);
 851         spin_lock(&idle->lock);
 852         idle_count = idle->idle_count;
 853         if (idle->idle_enter)
 854                 idle_count++;
 855         spin_unlock(&idle->lock);
 856         return sprintf(buf, "%llu\n", idle_count);
 857 }
 858 static SYSDEV_ATTR(idle_count, 0444, show_idle_count, NULL);
 859
 860 static ssize_t show_idle_time(struct sys_device *dev,
 861                                 struct sysdev_attribute *attr, char *buf)
 862 {
 863         struct s390_idle_data *idle;
 864         unsigned long long now, idle_time, idle_enter;
 865
 866         idle = &per_cpu(s390_idle, dev->id);
 867         spin_lock(&idle->lock);
 868         now = get_clock();
 869         idle_time = idle->idle_time;
 870         idle_enter = idle->idle_enter;
 871         if (idle_enter != 0ULL && idle_enter < now)
 872                 idle_time += now - idle_enter;
 873         spin_unlock(&idle->lock);
 874         return sprintf(buf, "%llu\n", idle_time >> 12);
 875 }
 876 static SYSDEV_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 877
 878 static struct attribute *cpu_online_attrs[] = {
 879         &attr_capability.attr,
 880         &attr_idle_count.attr,
 881         &attr_idle_time_us.attr,
 882         NULL,
 883 };
 884
 885 static struct attribute_group cpu_online_attr_group = {
 886         .attrs = cpu_online_attrs,
 887 };
 888
 889 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
 890                                     unsigned long action, void *hcpu)
 891 {
 892         unsigned int cpu = (unsigned int)(long)hcpu;
 893         struct cpu *c = &per_cpu(cpu_devices, cpu);
 894         struct sys_device *s = &c->sysdev;
 895         struct s390_idle_data *idle;
 896
 897         switch (action) {
 898         case CPU_ONLINE:
 899         case CPU_ONLINE_FROZEN:
 900                 idle = &per_cpu(s390_idle, cpu);
 901                 spin_lock_irq(&idle->lock);
 902                 idle->idle_enter = 0;
 903                 idle->idle_time = 0;
 904                 idle->idle_count = 0;
 905                 spin_unlock_irq(&idle->lock);
 906                 if (sysfs_create_group(&s->kobj, &cpu_online_attr_group))
 907                         return NOTIFY_BAD;
 908                 break;
 909         case CPU_DEAD:
 910         case CPU_DEAD_FROZEN:
 911                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
 912                 break;
 913         }
 914         return NOTIFY_OK;
 915 }
 916
 917 static struct notifier_block __cpuinitdata smp_cpu_nb = {
 918         .notifier_call = smp_cpu_notify,
 919 };
 920
 921 static int __devinit smp_add_present_cpu(int cpu)
 922 {
 923         struct cpu *c = &per_cpu(cpu_devices, cpu);
 924         struct sys_device *s = &c->sysdev;
 925         int rc;
 926
 927         c->hotpluggable = 1;
 928         rc = register_cpu(c, cpu);
 929         if (rc)
 930                 goto out;
 931         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 932         if (rc)
 933                 goto out_cpu;
 934         if (!cpu_online(cpu))
 935                 goto out;
 936         rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 937         if (!rc)
 938                 return 0;
 939         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
 940 out_cpu:
 941 #ifdef CONFIG_HOTPLUG_CPU
 942         unregister_cpu(c);
 943 #endif
 944 out:
 945         return rc;
 946 }
 947
 948 #ifdef CONFIG_HOTPLUG_CPU
 949
 950 int __ref smp_rescan_cpus(void)
 951 {
 952         cpumask_t newcpus;
 953         int cpu;
 954         int rc;
 955
 956         get_online_cpus();
 957         mutex_lock(&smp_cpu_state_mutex);
 958         newcpus = cpu_present_map;
 959         rc = __smp_rescan_cpus();
 960         if (rc)
 961                 goto out;
 962         cpus_andnot(newcpus, cpu_present_map, newcpus);
 963         for_each_cpu_mask(cpu, newcpus) {
 964                 rc = smp_add_present_cpu(cpu);
 965                 if (rc)
 966                         cpu_clear(cpu, cpu_present_map);
 967         }
 968         rc = 0;
 969 out:
 970         mutex_unlock(&smp_cpu_state_mutex);
 971         put_online_cpus();
 972         if (!cpus_empty(newcpus))
 973                 topology_schedule_update();
 974         return rc;
 975 }
 976
 977 static ssize_t __ref rescan_store(struct sysdev_class *class, const char *buf,
 978                                   size_t count)
 979 {
 980         int rc;
 981
 982         rc = smp_rescan_cpus();
 983         return rc ? rc : count;
 984 }
 985 static SYSDEV_CLASS_ATTR(rescan, 0200, NULL, rescan_store);
 986 #endif /* CONFIG_HOTPLUG_CPU */
 987
 988 static ssize_t dispatching_show(struct sysdev_class *class, char *buf)
 989 {
 990         ssize_t count;
 991
 992         mutex_lock(&smp_cpu_state_mutex);
 993         count = sprintf(buf, "%d\n", cpu_management);
 994         mutex_unlock(&smp_cpu_state_mutex);
 995         return count;
 996 }
 997
 998 static ssize_t dispatching_store(struct sysdev_class *dev, const char *buf,
 999                                  size_t count)
1000 {
1001         int val, rc;
1002         char delim;
1003
1004         if (sscanf(buf, "%d %c", &val, &delim) != 1)
1005                 return -EINVAL;
1006         if (val != 0 && val != 1)
1007                 return -EINVAL;
1008         rc = 0;
1009         get_online_cpus();
1010         mutex_lock(&smp_cpu_state_mutex);
1011         if (cpu_management == val)
1012                 goto out;
1013         rc = topology_set_cpu_management(val);
1014         if (!rc)
1015                 cpu_management = val;
1016 out:
1017         mutex_unlock(&smp_cpu_state_mutex);
1018         put_online_cpus();
1019         return rc ? rc : count;
1020 }
1021 static SYSDEV_CLASS_ATTR(dispatching, 0644, dispatching_show,
1022                          dispatching_store);
1023
1024 static int __init topology_init(void)
1025 {
1026         int cpu;
1027         int rc;
1028
1029         register_cpu_notifier(&smp_cpu_nb);
1030
1031 #ifdef CONFIG_HOTPLUG_CPU
1032         rc = sysdev_class_create_file(&cpu_sysdev_class, &attr_rescan);
1033         if (rc)
1034                 return rc;
1035 #endif
1036         rc = sysdev_class_create_file(&cpu_sysdev_class, &attr_dispatching);
1037         if (rc)
1038                 return rc;
1039         for_each_present_cpu(cpu) {
1040                 rc = smp_add_present_cpu(cpu);
1041                 if (rc)
1042                         return rc;
1043         }
1044         return 0;
1045 }
1046 subsys_initcall(topology_init);