arch/s390/kernel/smp.c

   1 /*
   2  *  arch/s390/kernel/smp.c
   3  *
   4  *    Copyright IBM Corp. 1999, 2009
   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/workqueue.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/mm.h>
  30 #include <linux/err.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/kernel_stat.h>
  33 #include <linux/delay.h>
  34 #include <linux/cache.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/irqflags.h>
  37 #include <linux/cpu.h>
  38 #include <linux/timex.h>
  39 #include <linux/bootmem.h>
  40 #include <linux/slab.h>
  41 #include <asm/asm-offsets.h>
  42 #include <asm/ipl.h>
  43 #include <asm/setup.h>
  44 #include <asm/sigp.h>
  45 #include <asm/pgalloc.h>
  46 #include <asm/irq.h>
  47 #include <asm/s390_ext.h>
  48 #include <asm/cpcmd.h>
  49 #include <asm/tlbflush.h>
  50 #include <asm/timer.h>
  51 #include <asm/lowcore.h>
  52 #include <asm/sclp.h>
  53 #include <asm/cputime.h>
  54 #include <asm/vdso.h>
  55 #include <asm/cpu.h>
  56 #include "entry.h"
  57
  58 /* logical cpu to cpu address */
  59 unsigned short __cpu_logical_map[NR_CPUS];
  60
  61 static struct task_struct *current_set[NR_CPUS];
  62
  63 static u8 smp_cpu_type;
  64 static int smp_use_sigp_detection;
  65
  66 enum s390_cpu_state {
  67         CPU_STATE_STANDBY,
  68         CPU_STATE_CONFIGURED,
  69 };
  70
  71 DEFINE_MUTEX(smp_cpu_state_mutex);
  72 int smp_cpu_polarization[NR_CPUS];
  73 static int smp_cpu_state[NR_CPUS];
  74 static int cpu_management;
  75
  76 static DEFINE_PER_CPU(struct cpu, cpu_devices);
  77
  78 static void smp_ext_bitcall(int, int);
  79
  80 static int raw_cpu_stopped(int cpu)
  81 {
  82         u32 status;
  83
  84         switch (raw_sigp_ps(&status, 0, cpu, sigp_sense)) {
  85         case sigp_status_stored:
  86                 /* Check for stopped and check stop state */
  87                 if (status & 0x50)
  88                         return 1;
  89                 break;
  90         default:
  91                 break;
  92         }
  93         return 0;
  94 }
  95
  96 static inline int cpu_stopped(int cpu)
  97 {
  98         return raw_cpu_stopped(cpu_logical_map(cpu));
  99 }
 100
 101 void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
 102 {
 103         struct _lowcore *lc, *current_lc;
 104         struct stack_frame *sf;
 105         struct pt_regs *regs;
 106         unsigned long sp;
 107
 108         if (smp_processor_id() == 0)
 109                 func(data);
 110         __load_psw_mask(PSW_BASE_BITS | PSW_DEFAULT_KEY);
 111         /* Disable lowcore protection */
 112         __ctl_clear_bit(0, 28);
 113         current_lc = lowcore_ptr[smp_processor_id()];
 114         lc = lowcore_ptr[0];
 115         if (!lc)
 116                 lc = current_lc;
 117         lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
 118         lc->restart_psw.addr = PSW_ADDR_AMODE | (unsigned long) smp_restart_cpu;
 119         if (!cpu_online(0))
 120                 smp_switch_to_cpu(func, data, 0, stap(), __cpu_logical_map[0]);
 121         while (sigp(0, sigp_stop_and_store_status) == sigp_busy)
 122                 cpu_relax();
 123         sp = lc->panic_stack;
 124         sp -= sizeof(struct pt_regs);
 125         regs = (struct pt_regs *) sp;
 126         memcpy(&regs->gprs, &current_lc->gpregs_save_area, sizeof(regs->gprs));
 127         regs->psw = lc->psw_save_area;
 128         sp -= STACK_FRAME_OVERHEAD;
 129         sf = (struct stack_frame *) sp;
 130         sf->back_chain = regs->gprs[15];
 131         smp_switch_to_cpu(func, data, sp, stap(), __cpu_logical_map[0]);
 132 }
 133
 134 void smp_send_stop(void)
 135 {
 136         int cpu, rc;
 137
 138         /* Disable all interrupts/machine checks */
 139         __load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
 140         trace_hardirqs_off();
 141
 142         /* stop all processors */
 143         for_each_online_cpu(cpu) {
 144                 if (cpu == smp_processor_id())
 145                         continue;
 146                 do {
 147                         rc = sigp(cpu, sigp_stop);
 148                 } while (rc == sigp_busy);
 149
 150                 while (!cpu_stopped(cpu))
 151                         cpu_relax();
 152         }
 153 }
 154
 155 /*
 156  * This is the main routine where commands issued by other
 157  * cpus are handled.
 158  */
 159
 160 static void do_ext_call_interrupt(unsigned int ext_int_code,
 161                                   unsigned int param32, unsigned long param64)
 162 {
 163         unsigned long bits;
 164
 165         kstat_cpu(smp_processor_id()).irqs[EXTINT_IPI]++;
 166         /*
 167          * handle bit signal external calls
 168          */
 169         bits = xchg(&S390_lowcore.ext_call_fast, 0);
 170
 171         if (test_bit(ec_schedule, &bits))
 172                 scheduler_ipi();
 173
 174         if (test_bit(ec_call_function, &bits))
 175                 generic_smp_call_function_interrupt();
 176
 177         if (test_bit(ec_call_function_single, &bits))
 178                 generic_smp_call_function_single_interrupt();
 179 }
 180
 181 /*
 182  * Send an external call sigp to another cpu and return without waiting
 183  * for its completion.
 184  */
 185 static void smp_ext_bitcall(int cpu, int sig)
 186 {
 187         /*
 188          * Set signaling bit in lowcore of target cpu and kick it
 189          */
 190         set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
 191         while (sigp(cpu, sigp_emergency_signal) == sigp_busy)
 192                 udelay(10);
 193 }
 194
 195 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 196 {
 197         int cpu;
 198
 199         for_each_cpu(cpu, mask)
 200                 smp_ext_bitcall(cpu, ec_call_function);
 201 }
 202
 203 void arch_send_call_function_single_ipi(int cpu)
 204 {
 205         smp_ext_bitcall(cpu, ec_call_function_single);
 206 }
 207
 208 #ifndef CONFIG_64BIT
 209 /*
 210  * this function sends a 'purge tlb' signal to another CPU.
 211  */
 212 static void smp_ptlb_callback(void *info)
 213 {
 214         __tlb_flush_local();
 215 }
 216
 217 void smp_ptlb_all(void)
 218 {
 219         on_each_cpu(smp_ptlb_callback, NULL, 1);
 220 }
 221 EXPORT_SYMBOL(smp_ptlb_all);
 222 #endif /* ! CONFIG_64BIT */
 223
 224 /*
 225  * this function sends a 'reschedule' IPI to another CPU.
 226  * it goes straight through and wastes no time serializing
 227  * anything. Worst case is that we lose a reschedule ...
 228  */
 229 void smp_send_reschedule(int cpu)
 230 {
 231         smp_ext_bitcall(cpu, ec_schedule);
 232 }
 233
 234 /*
 235  * parameter area for the set/clear control bit callbacks
 236  */
 237 struct ec_creg_mask_parms {
 238         unsigned long orvals[16];
 239         unsigned long andvals[16];
 240 };
 241
 242 /*
 243  * callback for setting/clearing control bits
 244  */
 245 static void smp_ctl_bit_callback(void *info)
 246 {
 247         struct ec_creg_mask_parms *pp = info;
 248         unsigned long cregs[16];
 249         int i;
 250
 251         __ctl_store(cregs, 0, 15);
 252         for (i = 0; i <= 15; i++)
 253                 cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
 254         __ctl_load(cregs, 0, 15);
 255 }
 256
 257 /*
 258  * Set a bit in a control register of all cpus
 259  */
 260 void smp_ctl_set_bit(int cr, int bit)
 261 {
 262         struct ec_creg_mask_parms parms;
 263
 264         memset(&parms.orvals, 0, sizeof(parms.orvals));
 265         memset(&parms.andvals, 0xff, sizeof(parms.andvals));
 266         parms.orvals[cr] = 1 << bit;
 267         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 268 }
 269 EXPORT_SYMBOL(smp_ctl_set_bit);
 270
 271 /*
 272  * Clear a bit in a control register of all cpus
 273  */
 274 void smp_ctl_clear_bit(int cr, int bit)
 275 {
 276         struct ec_creg_mask_parms parms;
 277
 278         memset(&parms.orvals, 0, sizeof(parms.orvals));
 279         memset(&parms.andvals, 0xff, sizeof(parms.andvals));
 280         parms.andvals[cr] = ~(1L << bit);
 281         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 282 }
 283 EXPORT_SYMBOL(smp_ctl_clear_bit);
 284
 285 #ifdef CONFIG_ZFCPDUMP
 286
 287 static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
 288 {
 289         if (ipl_info.type != IPL_TYPE_FCP_DUMP)
 290                 return;
 291         if (cpu >= NR_CPUS) {
 292                 pr_warning("CPU %i exceeds the maximum %i and is excluded from "
 293                            "the dump\n", cpu, NR_CPUS - 1);
 294                 return;
 295         }
 296         zfcpdump_save_areas[cpu] = kmalloc(sizeof(struct save_area), GFP_KERNEL);
 297         while (raw_sigp(phy_cpu, sigp_stop_and_store_status) == sigp_busy)
 298                 cpu_relax();
 299         memcpy_real(zfcpdump_save_areas[cpu],
 300                     (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
 301                     sizeof(struct save_area));
 302 }
 303
 304 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
 305 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
 306
 307 #else
 308
 309 static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }
 310
 311 #endif /* CONFIG_ZFCPDUMP */
 312
 313 static int cpu_known(int cpu_id)
 314 {
 315         int cpu;
 316
 317         for_each_present_cpu(cpu) {
 318                 if (__cpu_logical_map[cpu] == cpu_id)
 319                         return 1;
 320         }
 321         return 0;
 322 }
 323
 324 static int smp_rescan_cpus_sigp(cpumask_t avail)
 325 {
 326         int cpu_id, logical_cpu;
 327
 328         logical_cpu = cpumask_first(&avail);
 329         if (logical_cpu >= nr_cpu_ids)
 330                 return 0;
 331         for (cpu_id = 0; cpu_id <= MAX_CPU_ADDRESS; cpu_id++) {
 332                 if (cpu_known(cpu_id))
 333                         continue;
 334                 __cpu_logical_map[logical_cpu] = cpu_id;
 335                 smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
 336                 if (!cpu_stopped(logical_cpu))
 337                         continue;
 338                 cpu_set(logical_cpu, cpu_present_map);
 339                 smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
 340                 logical_cpu = cpumask_next(logical_cpu, &avail);
 341                 if (logical_cpu >= nr_cpu_ids)
 342                         break;
 343         }
 344         return 0;
 345 }
 346
 347 static int smp_rescan_cpus_sclp(cpumask_t avail)
 348 {
 349         struct sclp_cpu_info *info;
 350         int cpu_id, logical_cpu, cpu;
 351         int rc;
 352
 353         logical_cpu = cpumask_first(&avail);
 354         if (logical_cpu >= nr_cpu_ids)
 355                 return 0;
 356         info = kmalloc(sizeof(*info), GFP_KERNEL);
 357         if (!info)
 358                 return -ENOMEM;
 359         rc = sclp_get_cpu_info(info);
 360         if (rc)
 361                 goto out;
 362         for (cpu = 0; cpu < info->combined; cpu++) {
 363                 if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
 364                         continue;
 365                 cpu_id = info->cpu[cpu].address;
 366                 if (cpu_known(cpu_id))
 367                         continue;
 368                 __cpu_logical_map[logical_cpu] = cpu_id;
 369                 smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
 370                 cpu_set(logical_cpu, cpu_present_map);
 371                 if (cpu >= info->configured)
 372                         smp_cpu_state[logical_cpu] = CPU_STATE_STANDBY;
 373                 else
 374                         smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
 375                 logical_cpu = cpumask_next(logical_cpu, &avail);
 376                 if (logical_cpu >= nr_cpu_ids)
 377                         break;
 378         }
 379 out:
 380         kfree(info);
 381         return rc;
 382 }
 383
 384 static int __smp_rescan_cpus(void)
 385 {
 386         cpumask_t avail;
 387
 388         cpus_xor(avail, cpu_possible_map, cpu_present_map);
 389         if (smp_use_sigp_detection)
 390                 return smp_rescan_cpus_sigp(avail);
 391         else
 392                 return smp_rescan_cpus_sclp(avail);
 393 }
 394
 395 static void __init smp_detect_cpus(void)
 396 {
 397         unsigned int cpu, c_cpus, s_cpus;
 398         struct sclp_cpu_info *info;
 399         u16 boot_cpu_addr, cpu_addr;
 400
 401         c_cpus = 1;
 402         s_cpus = 0;
 403         boot_cpu_addr = __cpu_logical_map[0];
 404         info = kmalloc(sizeof(*info), GFP_KERNEL);
 405         if (!info)
 406                 panic("smp_detect_cpus failed to allocate memory\n");
 407         /* Use sigp detection algorithm if sclp doesn't work. */
 408         if (sclp_get_cpu_info(info)) {
 409                 smp_use_sigp_detection = 1;
 410                 for (cpu = 0; cpu <= MAX_CPU_ADDRESS; cpu++) {
 411                         if (cpu == boot_cpu_addr)
 412                                 continue;
 413                         if (!raw_cpu_stopped(cpu))
 414                                 continue;
 415                         smp_get_save_area(c_cpus, cpu);
 416                         c_cpus++;
 417                 }
 418                 goto out;
 419         }
 420
 421         if (info->has_cpu_type) {
 422                 for (cpu = 0; cpu < info->combined; cpu++) {
 423                         if (info->cpu[cpu].address == boot_cpu_addr) {
 424                                 smp_cpu_type = info->cpu[cpu].type;
 425                                 break;
 426                         }
 427                 }
 428         }
 429
 430         for (cpu = 0; cpu < info->combined; cpu++) {
 431                 if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
 432                         continue;
 433                 cpu_addr = info->cpu[cpu].address;
 434                 if (cpu_addr == boot_cpu_addr)
 435                         continue;
 436                 if (!raw_cpu_stopped(cpu_addr)) {
 437                         s_cpus++;
 438                         continue;
 439                 }
 440                 smp_get_save_area(c_cpus, cpu_addr);
 441                 c_cpus++;
 442         }
 443 out:
 444         kfree(info);
 445         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 446         get_online_cpus();
 447         __smp_rescan_cpus();
 448         put_online_cpus();
 449 }
 450
 451 /*
 452  *      Activate a secondary processor.
 453  */
 454 int __cpuinit start_secondary(void *cpuvoid)
 455 {
 456         /* Setup the cpu */
 457         cpu_init();
 458         preempt_disable();
 459         /* Enable TOD clock interrupts on the secondary cpu. */
 460         init_cpu_timer();
 461         /* Enable cpu timer interrupts on the secondary cpu. */
 462         init_cpu_vtimer();
 463         /* Enable pfault pseudo page faults on this cpu. */
 464         pfault_init();
 465
 466         /* call cpu notifiers */
 467         notify_cpu_starting(smp_processor_id());
 468         /* Mark this cpu as online */
 469         ipi_call_lock();
 470         cpu_set(smp_processor_id(), cpu_online_map);
 471         ipi_call_unlock();
 472         /* Switch on interrupts */
 473         local_irq_enable();
 474         /* cpu_idle will call schedule for us */
 475         cpu_idle();
 476         return 0;
 477 }
 478
 479 struct create_idle {
 480         struct work_struct work;
 481         struct task_struct *idle;
 482         struct completion done;
 483         int cpu;
 484 };
 485
 486 static void __cpuinit smp_fork_idle(struct work_struct *work)
 487 {
 488         struct create_idle *c_idle;
 489
 490         c_idle = container_of(work, struct create_idle, work);
 491         c_idle->idle = fork_idle(c_idle->cpu);
 492         complete(&c_idle->done);
 493 }
 494
 495 static int __cpuinit smp_alloc_lowcore(int cpu)
 496 {
 497         unsigned long async_stack, panic_stack;
 498         struct _lowcore *lowcore;
 499
 500         lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 501         if (!lowcore)
 502                 return -ENOMEM;
 503         async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 504         panic_stack = __get_free_page(GFP_KERNEL);
 505         if (!panic_stack || !async_stack)
 506                 goto out;
 507         memcpy(lowcore, &S390_lowcore, 512);
 508         memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
 509         lowcore->async_stack = async_stack + ASYNC_SIZE;
 510         lowcore->panic_stack = panic_stack + PAGE_SIZE;
 511
 512 #ifndef CONFIG_64BIT
 513         if (MACHINE_HAS_IEEE) {
 514                 unsigned long save_area;
 515
 516                 save_area = get_zeroed_page(GFP_KERNEL);
 517                 if (!save_area)
 518                         goto out;
 519                 lowcore->extended_save_area_addr = (u32) save_area;
 520         }
 521 #else
 522         if (vdso_alloc_per_cpu(cpu, lowcore))
 523                 goto out;
 524 #endif
 525         lowcore_ptr[cpu] = lowcore;
 526         return 0;
 527
 528 out:
 529         free_page(panic_stack);
 530         free_pages(async_stack, ASYNC_ORDER);
 531         free_pages((unsigned long) lowcore, LC_ORDER);
 532         return -ENOMEM;
 533 }
 534
 535 static void smp_free_lowcore(int cpu)
 536 {
 537         struct _lowcore *lowcore;
 538
 539         lowcore = lowcore_ptr[cpu];
 540 #ifndef CONFIG_64BIT
 541         if (MACHINE_HAS_IEEE)
 542                 free_page((unsigned long) lowcore->extended_save_area_addr);
 543 #else
 544         vdso_free_per_cpu(cpu, lowcore);
 545 #endif
 546         free_page(lowcore->panic_stack - PAGE_SIZE);
 547         free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
 548         free_pages((unsigned long) lowcore, LC_ORDER);
 549         lowcore_ptr[cpu] = NULL;
 550 }
 551
 552 /* Upping and downing of CPUs */
 553 int __cpuinit __cpu_up(unsigned int cpu)
 554 {
 555         struct _lowcore *cpu_lowcore;
 556         struct create_idle c_idle;
 557         struct task_struct *idle;
 558         struct stack_frame *sf;
 559         u32 lowcore;
 560         int ccode;
 561
 562         if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
 563                 return -EIO;
 564         idle = current_set[cpu];
 565         if (!idle) {
 566                 c_idle.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done);
 567                 INIT_WORK_ONSTACK(&c_idle.work, smp_fork_idle);
 568                 c_idle.cpu = cpu;
 569                 schedule_work(&c_idle.work);
 570                 wait_for_completion(&c_idle.done);
 571                 if (IS_ERR(c_idle.idle))
 572                         return PTR_ERR(c_idle.idle);
 573                 idle = c_idle.idle;
 574                 current_set[cpu] = c_idle.idle;
 575         }
 576         init_idle(idle, cpu);
 577         if (smp_alloc_lowcore(cpu))
 578                 return -ENOMEM;
 579         do {
 580                 ccode = sigp(cpu, sigp_initial_cpu_reset);
 581                 if (ccode == sigp_busy)
 582                         udelay(10);
 583                 if (ccode == sigp_not_operational)
 584                         goto err_out;
 585         } while (ccode == sigp_busy);
 586
 587         lowcore = (u32)(unsigned long)lowcore_ptr[cpu];
 588         while (sigp_p(lowcore, cpu, sigp_set_prefix) == sigp_busy)
 589                 udelay(10);
 590
 591         cpu_lowcore = lowcore_ptr[cpu];
 592         cpu_lowcore->kernel_stack = (unsigned long)
 593                 task_stack_page(idle) + THREAD_SIZE;
 594         cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
 595         sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
 596                                      - sizeof(struct pt_regs)
 597                                      - sizeof(struct stack_frame));
 598         memset(sf, 0, sizeof(struct stack_frame));
 599         sf->gprs[9] = (unsigned long) sf;
 600         cpu_lowcore->save_area[15] = (unsigned long) sf;
 601         __ctl_store(cpu_lowcore->cregs_save_area, 0, 15);
 602         atomic_inc(&init_mm.context.attach_count);
 603         asm volatile(
 604                 "       stam    0,15,0(%0)"
 605                 : : "a" (&cpu_lowcore->access_regs_save_area) : "memory");
 606         cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
 607         cpu_lowcore->current_task = (unsigned long) idle;
 608         cpu_lowcore->cpu_nr = cpu;
 609         cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
 610         cpu_lowcore->machine_flags = S390_lowcore.machine_flags;
 611         cpu_lowcore->ftrace_func = S390_lowcore.ftrace_func;
 612         memcpy(cpu_lowcore->stfle_fac_list, S390_lowcore.stfle_fac_list,
 613                MAX_FACILITY_BIT/8);
 614         eieio();
 615
 616         while (sigp(cpu, sigp_restart) == sigp_busy)
 617                 udelay(10);
 618
 619         while (!cpu_online(cpu))
 620                 cpu_relax();
 621         return 0;
 622
 623 err_out:
 624         smp_free_lowcore(cpu);
 625         return -EIO;
 626 }
 627
 628 static int __init setup_possible_cpus(char *s)
 629 {
 630         int pcpus, cpu;
 631
 632         pcpus = simple_strtoul(s, NULL, 0);
 633         init_cpu_possible(cpumask_of(0));
 634         for (cpu = 1; cpu < pcpus && cpu < nr_cpu_ids; cpu++)
 635                 set_cpu_possible(cpu, true);
 636         return 0;
 637 }
 638 early_param("possible_cpus", setup_possible_cpus);
 639
 640 #ifdef CONFIG_HOTPLUG_CPU
 641
 642 int __cpu_disable(void)
 643 {
 644         struct ec_creg_mask_parms cr_parms;
 645         int cpu = smp_processor_id();
 646
 647         cpu_clear(cpu, cpu_online_map);
 648
 649         /* Disable pfault pseudo page faults on this cpu. */
 650         pfault_fini();
 651
 652         memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));
 653         memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));
 654
 655         /* disable all external interrupts */
 656         cr_parms.orvals[0] = 0;
 657         cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 12 |
 658                                 1 << 11 | 1 << 10 | 1 <<  6 | 1 <<  4);
 659         /* disable all I/O interrupts */
 660         cr_parms.orvals[6] = 0;
 661         cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |
 662                                 1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);
 663         /* disable most machine checks */
 664         cr_parms.orvals[14] = 0;
 665         cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |
 666                                  1 << 25 | 1 << 24);
 667
 668         smp_ctl_bit_callback(&cr_parms);
 669
 670         return 0;
 671 }
 672
 673 void __cpu_die(unsigned int cpu)
 674 {
 675         /* Wait until target cpu is down */
 676         while (!cpu_stopped(cpu))
 677                 cpu_relax();
 678         while (sigp_p(0, cpu, sigp_set_prefix) == sigp_busy)
 679                 udelay(10);
 680         smp_free_lowcore(cpu);
 681         atomic_dec(&init_mm.context.attach_count);
 682 }
 683
 684 void cpu_die(void)
 685 {
 686         idle_task_exit();
 687         while (sigp(smp_processor_id(), sigp_stop) == sigp_busy)
 688                 cpu_relax();
 689         for (;;);
 690 }
 691
 692 #endif /* CONFIG_HOTPLUG_CPU */
 693
 694 void __init smp_prepare_cpus(unsigned int max_cpus)
 695 {
 696 #ifndef CONFIG_64BIT
 697         unsigned long save_area = 0;
 698 #endif
 699         unsigned long async_stack, panic_stack;
 700         struct _lowcore *lowcore;
 701
 702         smp_detect_cpus();
 703
 704         /* request the 0x1201 emergency signal external interrupt */
 705         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
 706                 panic("Couldn't request external interrupt 0x1201");
 707
 708         /* Reallocate current lowcore, but keep its contents. */
 709         lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 710         panic_stack = __get_free_page(GFP_KERNEL);
 711         async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 712         BUG_ON(!lowcore || !panic_stack || !async_stack);
 713 #ifndef CONFIG_64BIT
 714         if (MACHINE_HAS_IEEE)
 715                 save_area = get_zeroed_page(GFP_KERNEL);
 716 #endif
 717         local_irq_disable();
 718         local_mcck_disable();
 719         lowcore_ptr[smp_processor_id()] = lowcore;
 720         *lowcore = S390_lowcore;
 721         lowcore->panic_stack = panic_stack + PAGE_SIZE;
 722         lowcore->async_stack = async_stack + ASYNC_SIZE;
 723 #ifndef CONFIG_64BIT
 724         if (MACHINE_HAS_IEEE)
 725                 lowcore->extended_save_area_addr = (u32) save_area;
 726 #endif
 727         set_prefix((u32)(unsigned long) lowcore);
 728         local_mcck_enable();
 729         local_irq_enable();
 730 #ifdef CONFIG_64BIT
 731         if (vdso_alloc_per_cpu(smp_processor_id(), &S390_lowcore))
 732                 BUG();
 733 #endif
 734 }
 735
 736 void __init smp_prepare_boot_cpu(void)
 737 {
 738         BUG_ON(smp_processor_id() != 0);
 739
 740         current_thread_info()->cpu = 0;
 741         cpu_set(0, cpu_present_map);
 742         cpu_set(0, cpu_online_map);
 743         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 744         current_set[0] = current;
 745         smp_cpu_state[0] = CPU_STATE_CONFIGURED;
 746         smp_cpu_polarization[0] = POLARIZATION_UNKNWN;
 747 }
 748
 749 void __init smp_cpus_done(unsigned int max_cpus)
 750 {
 751 }
 752
 753 void __init smp_setup_processor_id(void)
 754 {
 755         S390_lowcore.cpu_nr = 0;
 756         __cpu_logical_map[0] = stap();
 757 }
 758
 759 /*
 760  * the frequency of the profiling timer can be changed
 761  * by writing a multiplier value into /proc/profile.
 762  *
 763  * usually you want to run this on all CPUs ;)
 764  */
 765 int setup_profiling_timer(unsigned int multiplier)
 766 {
 767         return 0;
 768 }
 769
 770 #ifdef CONFIG_HOTPLUG_CPU
 771 static ssize_t cpu_configure_show(struct sys_device *dev,
 772                                 struct sysdev_attribute *attr, char *buf)
 773 {
 774         ssize_t count;
 775
 776         mutex_lock(&smp_cpu_state_mutex);
 777         count = sprintf(buf, "%d\n", smp_cpu_state[dev->id]);
 778         mutex_unlock(&smp_cpu_state_mutex);
 779         return count;
 780 }
 781
 782 static ssize_t cpu_configure_store(struct sys_device *dev,
 783                                   struct sysdev_attribute *attr,
 784                                   const char *buf, size_t count)
 785 {
 786         int cpu = dev->id;
 787         int val, rc;
 788         char delim;
 789
 790         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 791                 return -EINVAL;
 792         if (val != 0 && val != 1)
 793                 return -EINVAL;
 794
 795         get_online_cpus();
 796         mutex_lock(&smp_cpu_state_mutex);
 797         rc = -EBUSY;
 798         /* disallow configuration changes of online cpus and cpu 0 */
 799         if (cpu_online(cpu) || cpu == 0)
 800                 goto out;
 801         rc = 0;
 802         switch (val) {
 803         case 0:
 804                 if (smp_cpu_state[cpu] == CPU_STATE_CONFIGURED) {
 805                         rc = sclp_cpu_deconfigure(__cpu_logical_map[cpu]);
 806                         if (!rc) {
 807                                 smp_cpu_state[cpu] = CPU_STATE_STANDBY;
 808                                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
 809                         }
 810                 }
 811                 break;
 812         case 1:
 813                 if (smp_cpu_state[cpu] == CPU_STATE_STANDBY) {
 814                         rc = sclp_cpu_configure(__cpu_logical_map[cpu]);
 815                         if (!rc) {
 816                                 smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
 817                                 smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
 818                         }
 819                 }
 820                 break;
 821         default:
 822                 break;
 823         }
 824 out:
 825         mutex_unlock(&smp_cpu_state_mutex);
 826         put_online_cpus();
 827         return rc ? rc : count;
 828 }
 829 static SYSDEV_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
 830 #endif /* CONFIG_HOTPLUG_CPU */
 831
 832 static ssize_t cpu_polarization_show(struct sys_device *dev,
 833                                      struct sysdev_attribute *attr, char *buf)
 834 {
 835         int cpu = dev->id;
 836         ssize_t count;
 837
 838         mutex_lock(&smp_cpu_state_mutex);
 839         switch (smp_cpu_polarization[cpu]) {
 840         case POLARIZATION_HRZ:
 841                 count = sprintf(buf, "horizontal\n");
 842                 break;
 843         case POLARIZATION_VL:
 844                 count = sprintf(buf, "vertical:low\n");
 845                 break;
 846         case POLARIZATION_VM:
 847                 count = sprintf(buf, "vertical:medium\n");
 848                 break;
 849         case POLARIZATION_VH:
 850                 count = sprintf(buf, "vertical:high\n");
 851                 break;
 852         default:
 853                 count = sprintf(buf, "unknown\n");
 854                 break;
 855         }
 856         mutex_unlock(&smp_cpu_state_mutex);
 857         return count;
 858 }
 859 static SYSDEV_ATTR(polarization, 0444, cpu_polarization_show, NULL);
 860
 861 static ssize_t show_cpu_address(struct sys_device *dev,
 862                                 struct sysdev_attribute *attr, char *buf)
 863 {
 864         return sprintf(buf, "%d\n", __cpu_logical_map[dev->id]);
 865 }
 866 static SYSDEV_ATTR(address, 0444, show_cpu_address, NULL);
 867
 868
 869 static struct attribute *cpu_common_attrs[] = {
 870 #ifdef CONFIG_HOTPLUG_CPU
 871         &attr_configure.attr,
 872 #endif
 873         &attr_address.attr,
 874         &attr_polarization.attr,
 875         NULL,
 876 };
 877
 878 static struct attribute_group cpu_common_attr_group = {
 879         .attrs = cpu_common_attrs,
 880 };
 881
 882 static ssize_t show_capability(struct sys_device *dev,
 883                                 struct sysdev_attribute *attr, char *buf)
 884 {
 885         unsigned int capability;
 886         int rc;
 887
 888         rc = get_cpu_capability(&capability);
 889         if (rc)
 890                 return rc;
 891         return sprintf(buf, "%u\n", capability);
 892 }
 893 static SYSDEV_ATTR(capability, 0444, show_capability, NULL);
 894
 895 static ssize_t show_idle_count(struct sys_device *dev,
 896                                 struct sysdev_attribute *attr, char *buf)
 897 {
 898         struct s390_idle_data *idle;
 899         unsigned long long idle_count;
 900         unsigned int sequence;
 901
 902         idle = &per_cpu(s390_idle, dev->id);
 903 repeat:
 904         sequence = idle->sequence;
 905         smp_rmb();
 906         if (sequence & 1)
 907                 goto repeat;
 908         idle_count = idle->idle_count;
 909         if (idle->idle_enter)
 910                 idle_count++;
 911         smp_rmb();
 912         if (idle->sequence != sequence)
 913                 goto repeat;
 914         return sprintf(buf, "%llu\n", idle_count);
 915 }
 916 static SYSDEV_ATTR(idle_count, 0444, show_idle_count, NULL);
 917
 918 static ssize_t show_idle_time(struct sys_device *dev,
 919                                 struct sysdev_attribute *attr, char *buf)
 920 {
 921         struct s390_idle_data *idle;
 922         unsigned long long now, idle_time, idle_enter;
 923         unsigned int sequence;
 924
 925         idle = &per_cpu(s390_idle, dev->id);
 926         now = get_clock();
 927 repeat:
 928         sequence = idle->sequence;
 929         smp_rmb();
 930         if (sequence & 1)
 931                 goto repeat;
 932         idle_time = idle->idle_time;
 933         idle_enter = idle->idle_enter;
 934         if (idle_enter != 0ULL && idle_enter < now)
 935                 idle_time += now - idle_enter;
 936         smp_rmb();
 937         if (idle->sequence != sequence)
 938                 goto repeat;
 939         return sprintf(buf, "%llu\n", idle_time >> 12);
 940 }
 941 static SYSDEV_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 942
 943 static struct attribute *cpu_online_attrs[] = {
 944         &attr_capability.attr,
 945         &attr_idle_count.attr,
 946         &attr_idle_time_us.attr,
 947         NULL,
 948 };
 949
 950 static struct attribute_group cpu_online_attr_group = {
 951         .attrs = cpu_online_attrs,
 952 };
 953
 954 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
 955                                     unsigned long action, void *hcpu)
 956 {
 957         unsigned int cpu = (unsigned int)(long)hcpu;
 958         struct cpu *c = &per_cpu(cpu_devices, cpu);
 959         struct sys_device *s = &c->sysdev;
 960         struct s390_idle_data *idle;
 961         int err = 0;
 962
 963         switch (action) {
 964         case CPU_ONLINE:
 965         case CPU_ONLINE_FROZEN:
 966                 idle = &per_cpu(s390_idle, cpu);
 967                 memset(idle, 0, sizeof(struct s390_idle_data));
 968                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 969                 break;
 970         case CPU_DEAD:
 971         case CPU_DEAD_FROZEN:
 972                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
 973                 break;
 974         }
 975         return notifier_from_errno(err);
 976 }
 977
 978 static struct notifier_block __cpuinitdata smp_cpu_nb = {
 979         .notifier_call = smp_cpu_notify,
 980 };
 981
 982 static int __devinit smp_add_present_cpu(int cpu)
 983 {
 984         struct cpu *c = &per_cpu(cpu_devices, cpu);
 985         struct sys_device *s = &c->sysdev;
 986         int rc;
 987
 988         c->hotpluggable = 1;
 989         rc = register_cpu(c, cpu);
 990         if (rc)
 991                 goto out;
 992         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
 993         if (rc)
 994                 goto out_cpu;
 995         if (!cpu_online(cpu))
 996                 goto out;
 997         rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 998         if (!rc)
 999                 return 0;
1000         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1001 out_cpu:
1002 #ifdef CONFIG_HOTPLUG_CPU
1003         unregister_cpu(c);
1004 #endif
1005 out:
1006         return rc;
1007 }
1008
1009 #ifdef CONFIG_HOTPLUG_CPU
1010
1011 int __ref smp_rescan_cpus(void)
1012 {
1013         cpumask_t newcpus;
1014         int cpu;
1015         int rc;
1016
1017         get_online_cpus();
1018         mutex_lock(&smp_cpu_state_mutex);
1019         newcpus = cpu_present_map;
1020         rc = __smp_rescan_cpus();
1021         if (rc)
1022                 goto out;
1023         cpus_andnot(newcpus, cpu_present_map, newcpus);
1024         for_each_cpu_mask(cpu, newcpus) {
1025                 rc = smp_add_present_cpu(cpu);
1026                 if (rc)
1027                         cpu_clear(cpu, cpu_present_map);
1028         }
1029         rc = 0;
1030 out:
1031         mutex_unlock(&smp_cpu_state_mutex);
1032         put_online_cpus();
1033         if (!cpus_empty(newcpus))
1034                 topology_schedule_update();
1035         return rc;
1036 }
1037
1038 static ssize_t __ref rescan_store(struct sysdev_class *class,
1039                                   struct sysdev_class_attribute *attr,
1040                                   const char *buf,
1041                                   size_t count)
1042 {
1043         int rc;
1044
1045         rc = smp_rescan_cpus();
1046         return rc ? rc : count;
1047 }
1048 static SYSDEV_CLASS_ATTR(rescan, 0200, NULL, rescan_store);
1049 #endif /* CONFIG_HOTPLUG_CPU */
1050
1051 static ssize_t dispatching_show(struct sysdev_class *class,
1052                                 struct sysdev_class_attribute *attr,
1053                                 char *buf)
1054 {
1055         ssize_t count;
1056
1057         mutex_lock(&smp_cpu_state_mutex);
1058         count = sprintf(buf, "%d\n", cpu_management);
1059         mutex_unlock(&smp_cpu_state_mutex);
1060         return count;
1061 }
1062
1063 static ssize_t dispatching_store(struct sysdev_class *dev,
1064                                  struct sysdev_class_attribute *attr,
1065                                  const char *buf,
1066                                  size_t count)
1067 {
1068         int val, rc;
1069         char delim;
1070
1071         if (sscanf(buf, "%d %c", &val, &delim) != 1)
1072                 return -EINVAL;
1073         if (val != 0 && val != 1)
1074                 return -EINVAL;
1075         rc = 0;
1076         get_online_cpus();
1077         mutex_lock(&smp_cpu_state_mutex);
1078         if (cpu_management == val)
1079                 goto out;
1080         rc = topology_set_cpu_management(val);
1081         if (!rc)
1082                 cpu_management = val;
1083 out:
1084         mutex_unlock(&smp_cpu_state_mutex);
1085         put_online_cpus();
1086         return rc ? rc : count;
1087 }
1088 static SYSDEV_CLASS_ATTR(dispatching, 0644, dispatching_show,
1089                          dispatching_store);
1090
1091 static int __init topology_init(void)
1092 {
1093         int cpu;
1094         int rc;
1095
1096         register_cpu_notifier(&smp_cpu_nb);
1097
1098 #ifdef CONFIG_HOTPLUG_CPU
1099         rc = sysdev_class_create_file(&cpu_sysdev_class, &attr_rescan);
1100         if (rc)
1101                 return rc;
1102 #endif
1103         rc = sysdev_class_create_file(&cpu_sysdev_class, &attr_dispatching);
1104         if (rc)
1105                 return rc;
1106         for_each_present_cpu(cpu) {
1107                 rc = smp_add_present_cpu(cpu);
1108                 if (rc)
1109                         return rc;
1110         }
1111         return 0;
1112 }
1113 subsys_initcall(topology_init);