Pileus Git - ~andy/linux/blob - arch/s390/kernel/smp.c

   1 /*
   2  *  SMP related functions
   3  *
   4  *    Copyright IBM Corp. 1999,2012
   5  *    Author(s): Denis Joseph Barrow,
   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  * The code outside of smp.c uses logical cpu numbers, only smp.c does
  14  * the translation of logical to physical cpu ids. All new code that
  15  * operates on physical cpu numbers needs to go into smp.c.
  16  */
  17
  18 #define KMSG_COMPONENT "cpu"
  19 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  20
  21 #include <linux/workqueue.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/mm.h>
  25 #include <linux/err.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/kernel_stat.h>
  28 #include <linux/delay.h>
  29 #include <linux/interrupt.h>
  30 #include <linux/irqflags.h>
  31 #include <linux/cpu.h>
  32 #include <linux/slab.h>
  33 #include <linux/crash_dump.h>
  34 #include <asm/asm-offsets.h>
  35 #include <asm/switch_to.h>
  36 #include <asm/facility.h>
  37 #include <asm/ipl.h>
  38 #include <asm/setup.h>
  39 #include <asm/irq.h>
  40 #include <asm/tlbflush.h>
  41 #include <asm/timer.h>
  42 #include <asm/lowcore.h>
  43 #include <asm/sclp.h>
  44 #include <asm/vdso.h>
  45 #include <asm/debug.h>
  46 #include <asm/os_info.h>
  47 #include "entry.h"
  48
  49 enum {
  50         sigp_sense = 1,
  51         sigp_external_call = 2,
  52         sigp_emergency_signal = 3,
  53         sigp_start = 4,
  54         sigp_stop = 5,
  55         sigp_restart = 6,
  56         sigp_stop_and_store_status = 9,
  57         sigp_initial_cpu_reset = 11,
  58         sigp_cpu_reset = 12,
  59         sigp_set_prefix = 13,
  60         sigp_store_status_at_address = 14,
  61         sigp_store_extended_status_at_address = 15,
  62         sigp_set_architecture = 18,
  63         sigp_conditional_emergency_signal = 19,
  64         sigp_sense_running = 21,
  65 };
  66
  67 enum {
  68         sigp_order_code_accepted = 0,
  69         sigp_status_stored = 1,
  70         sigp_busy = 2,
  71         sigp_not_operational = 3,
  72 };
  73
  74 enum {
  75         ec_schedule = 0,
  76         ec_call_function,
  77         ec_call_function_single,
  78         ec_stop_cpu,
  79 };
  80
  81 enum {
  82         CPU_STATE_STANDBY,
  83         CPU_STATE_CONFIGURED,
  84 };
  85
  86 struct pcpu {
  87         struct cpu cpu;
  88         struct _lowcore *lowcore;       /* lowcore page(s) for the cpu */
  89         unsigned long async_stack;      /* async stack for the cpu */
  90         unsigned long panic_stack;      /* panic stack for the cpu */
  91         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  92         int state;                      /* physical cpu state */
  93         u32 status;                     /* last status received via sigp */
  94         u16 address;                    /* physical cpu address */
  95 };
  96
  97 static u8 boot_cpu_type;
  98 static u16 boot_cpu_address;
  99 static struct pcpu pcpu_devices[NR_CPUS];
 100
 101 DEFINE_MUTEX(smp_cpu_state_mutex);
 102
 103 /*
 104  * Signal processor helper functions.
 105  */
 106 static inline int __pcpu_sigp(u16 addr, u8 order, u32 parm, u32 *status)
 107 {
 108         register unsigned int reg1 asm ("1") = parm;
 109         int cc;
 110
 111         asm volatile(
 112                 "       sigp    %1,%2,0(%3)\n"
 113                 "       ipm     %0\n"
 114                 "       srl     %0,28\n"
 115                 : "=d" (cc), "+d" (reg1) : "d" (addr), "a" (order) : "cc");
 116         if (status && cc == 1)
 117                 *status = reg1;
 118         return cc;
 119 }
 120
 121 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
 122 {
 123         int cc;
 124
 125         while (1) {
 126                 cc = __pcpu_sigp(addr, order, parm, status);
 127                 if (cc != sigp_busy)
 128                         return cc;
 129                 cpu_relax();
 130         }
 131 }
 132
 133 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 134 {
 135         int cc, retry;
 136
 137         for (retry = 0; ; retry++) {
 138                 cc = __pcpu_sigp(pcpu->address, order, parm, &pcpu->status);
 139                 if (cc != sigp_busy)
 140                         break;
 141                 if (retry >= 3)
 142                         udelay(10);
 143         }
 144         return cc;
 145 }
 146
 147 static inline int pcpu_stopped(struct pcpu *pcpu)
 148 {
 149         if (__pcpu_sigp(pcpu->address, sigp_sense,
 150                         0, &pcpu->status) != sigp_status_stored)
 151                 return 0;
 152         /* Check for stopped and check stop state */
 153         return !!(pcpu->status & 0x50);
 154 }
 155
 156 static inline int pcpu_running(struct pcpu *pcpu)
 157 {
 158         if (__pcpu_sigp(pcpu->address, sigp_sense_running,
 159                         0, &pcpu->status) != sigp_status_stored)
 160                 return 1;
 161         /* Check for running status */
 162         return !(pcpu->status & 0x400);
 163 }
 164
 165 /*
 166  * Find struct pcpu by cpu address.
 167  */
 168 static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
 169 {
 170         int cpu;
 171
 172         for_each_cpu(cpu, mask)
 173                 if (pcpu_devices[cpu].address == address)
 174                         return pcpu_devices + cpu;
 175         return NULL;
 176 }
 177
 178 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 179 {
 180         int order;
 181
 182         set_bit(ec_bit, &pcpu->ec_mask);
 183         order = pcpu_running(pcpu) ?
 184                 sigp_external_call : sigp_emergency_signal;
 185         pcpu_sigp_retry(pcpu, order, 0);
 186 }
 187
 188 static int __cpuinit pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 189 {
 190         struct _lowcore *lc;
 191
 192         if (pcpu != &pcpu_devices[0]) {
 193                 pcpu->lowcore = (struct _lowcore *)
 194                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 195                 pcpu->async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 196                 pcpu->panic_stack = __get_free_page(GFP_KERNEL);
 197                 if (!pcpu->lowcore || !pcpu->panic_stack || !pcpu->async_stack)
 198                         goto out;
 199         }
 200         lc = pcpu->lowcore;
 201         memcpy(lc, &S390_lowcore, 512);
 202         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 203         lc->async_stack = pcpu->async_stack + ASYNC_SIZE;
 204         lc->panic_stack = pcpu->panic_stack + PAGE_SIZE;
 205         lc->cpu_nr = cpu;
 206 #ifndef CONFIG_64BIT
 207         if (MACHINE_HAS_IEEE) {
 208                 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
 209                 if (!lc->extended_save_area_addr)
 210                         goto out;
 211         }
 212 #else
 213         if (vdso_alloc_per_cpu(lc))
 214                 goto out;
 215 #endif
 216         lowcore_ptr[cpu] = lc;
 217         pcpu_sigp_retry(pcpu, sigp_set_prefix, (u32)(unsigned long) lc);
 218         return 0;
 219 out:
 220         if (pcpu != &pcpu_devices[0]) {
 221                 free_page(pcpu->panic_stack);
 222                 free_pages(pcpu->async_stack, ASYNC_ORDER);
 223                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 224         }
 225         return -ENOMEM;
 226 }
 227
 228 #ifdef CONFIG_HOTPLUG_CPU
 229
 230 static void pcpu_free_lowcore(struct pcpu *pcpu)
 231 {
 232         pcpu_sigp_retry(pcpu, sigp_set_prefix, 0);
 233         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 234 #ifndef CONFIG_64BIT
 235         if (MACHINE_HAS_IEEE) {
 236                 struct _lowcore *lc = pcpu->lowcore;
 237
 238                 free_page((unsigned long) lc->extended_save_area_addr);
 239                 lc->extended_save_area_addr = 0;
 240         }
 241 #else
 242         vdso_free_per_cpu(pcpu->lowcore);
 243 #endif
 244         if (pcpu != &pcpu_devices[0]) {
 245                 free_page(pcpu->panic_stack);
 246                 free_pages(pcpu->async_stack, ASYNC_ORDER);
 247                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 248         }
 249 }
 250
 251 #endif /* CONFIG_HOTPLUG_CPU */
 252
 253 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 254 {
 255         struct _lowcore *lc = pcpu->lowcore;
 256
 257         atomic_inc(&init_mm.context.attach_count);
 258         lc->cpu_nr = cpu;
 259         lc->percpu_offset = __per_cpu_offset[cpu];
 260         lc->kernel_asce = S390_lowcore.kernel_asce;
 261         lc->machine_flags = S390_lowcore.machine_flags;
 262         lc->ftrace_func = S390_lowcore.ftrace_func;
 263         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 264         __ctl_store(lc->cregs_save_area, 0, 15);
 265         save_access_regs((unsigned int *) lc->access_regs_save_area);
 266         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 267                MAX_FACILITY_BIT/8);
 268 }
 269
 270 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 271 {
 272         struct _lowcore *lc = pcpu->lowcore;
 273         struct thread_info *ti = task_thread_info(tsk);
 274
 275         lc->kernel_stack = (unsigned long) task_stack_page(tsk) + THREAD_SIZE;
 276         lc->thread_info = (unsigned long) task_thread_info(tsk);
 277         lc->current_task = (unsigned long) tsk;
 278         lc->user_timer = ti->user_timer;
 279         lc->system_timer = ti->system_timer;
 280         lc->steal_timer = 0;
 281 }
 282
 283 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 284 {
 285         struct _lowcore *lc = pcpu->lowcore;
 286
 287         lc->restart_stack = lc->kernel_stack;
 288         lc->restart_fn = (unsigned long) func;
 289         lc->restart_data = (unsigned long) data;
 290         lc->restart_source = -1UL;
 291         pcpu_sigp_retry(pcpu, sigp_restart, 0);
 292 }
 293
 294 /*
 295  * Call function via PSW restart on pcpu and stop the current cpu.
 296  */
 297 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 298                           void *data, unsigned long stack)
 299 {
 300         struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 301         struct {
 302                 unsigned long   stack;
 303                 void            *func;
 304                 void            *data;
 305                 unsigned long   source;
 306         } restart = { stack, func, data, stap() };
 307
 308         __load_psw_mask(psw_kernel_bits);
 309         if (pcpu->address == restart.source)
 310                 func(data);     /* should not return */
 311         /* Stop target cpu (if func returns this stops the current cpu). */
 312         pcpu_sigp_retry(pcpu, sigp_stop, 0);
 313         /* Restart func on the target cpu and stop the current cpu. */
 314         memcpy_absolute(&lc->restart_stack, &restart, sizeof(restart));
 315         asm volatile(
 316                 "0:     sigp    0,%0,6  # sigp restart to target cpu\n"
 317                 "       brc     2,0b    # busy, try again\n"
 318                 "1:     sigp    0,%1,5  # sigp stop to current cpu\n"
 319                 "       brc     2,1b    # busy, try again\n"
 320                 : : "d" (pcpu->address), "d" (restart.source) : "0", "1", "cc");
 321         for (;;) ;
 322 }
 323
 324 /*
 325  * Call function on an online CPU.
 326  */
 327 void smp_call_online_cpu(void (*func)(void *), void *data)
 328 {
 329         struct pcpu *pcpu;
 330
 331         /* Use the current cpu if it is online. */
 332         pcpu = pcpu_find_address(cpu_online_mask, stap());
 333         if (!pcpu)
 334                 /* Use the first online cpu. */
 335                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 336         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 337 }
 338
 339 /*
 340  * Call function on the ipl CPU.
 341  */
 342 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 343 {
 344         pcpu_delegate(&pcpu_devices[0], func, data,
 345                       pcpu_devices->panic_stack + PAGE_SIZE);
 346 }
 347
 348 int smp_find_processor_id(u16 address)
 349 {
 350         int cpu;
 351
 352         for_each_present_cpu(cpu)
 353                 if (pcpu_devices[cpu].address == address)
 354                         return cpu;
 355         return -1;
 356 }
 357
 358 int smp_vcpu_scheduled(int cpu)
 359 {
 360         return pcpu_running(pcpu_devices + cpu);
 361 }
 362
 363 void smp_yield(void)
 364 {
 365         if (MACHINE_HAS_DIAG44)
 366                 asm volatile("diag 0,0,0x44");
 367 }
 368
 369 void smp_yield_cpu(int cpu)
 370 {
 371         if (MACHINE_HAS_DIAG9C)
 372                 asm volatile("diag %0,0,0x9c"
 373                              : : "d" (pcpu_devices[cpu].address));
 374         else if (MACHINE_HAS_DIAG44)
 375                 asm volatile("diag 0,0,0x44");
 376 }
 377
 378 /*
 379  * Send cpus emergency shutdown signal. This gives the cpus the
 380  * opportunity to complete outstanding interrupts.
 381  */
 382 void smp_emergency_stop(cpumask_t *cpumask)
 383 {
 384         u64 end;
 385         int cpu;
 386
 387         end = get_clock() + (1000000UL << 12);
 388         for_each_cpu(cpu, cpumask) {
 389                 struct pcpu *pcpu = pcpu_devices + cpu;
 390                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 391                 while (__pcpu_sigp(pcpu->address, sigp_emergency_signal,
 392                                    0, NULL) == sigp_busy &&
 393                        get_clock() < end)
 394                         cpu_relax();
 395         }
 396         while (get_clock() < end) {
 397                 for_each_cpu(cpu, cpumask)
 398                         if (pcpu_stopped(pcpu_devices + cpu))
 399                                 cpumask_clear_cpu(cpu, cpumask);
 400                 if (cpumask_empty(cpumask))
 401                         break;
 402                 cpu_relax();
 403         }
 404 }
 405
 406 /*
 407  * Stop all cpus but the current one.
 408  */
 409 void smp_send_stop(void)
 410 {
 411         cpumask_t cpumask;
 412         int cpu;
 413
 414         /* Disable all interrupts/machine checks */
 415         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
 416         trace_hardirqs_off();
 417
 418         debug_set_critical();
 419         cpumask_copy(&cpumask, cpu_online_mask);
 420         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 421
 422         if (oops_in_progress)
 423                 smp_emergency_stop(&cpumask);
 424
 425         /* stop all processors */
 426         for_each_cpu(cpu, &cpumask) {
 427                 struct pcpu *pcpu = pcpu_devices + cpu;
 428                 pcpu_sigp_retry(pcpu, sigp_stop, 0);
 429                 while (!pcpu_stopped(pcpu))
 430                         cpu_relax();
 431         }
 432 }
 433
 434 /*
 435  * Stop the current cpu.
 436  */
 437 void smp_stop_cpu(void)
 438 {
 439         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), sigp_stop, 0);
 440         for (;;) ;
 441 }
 442
 443 /*
 444  * This is the main routine where commands issued by other
 445  * cpus are handled.
 446  */
 447 static void do_ext_call_interrupt(struct ext_code ext_code,
 448                                   unsigned int param32, unsigned long param64)
 449 {
 450         unsigned long bits;
 451         int cpu;
 452
 453         cpu = smp_processor_id();
 454         if (ext_code.code == 0x1202)
 455                 kstat_cpu(cpu).irqs[EXTINT_EXC]++;
 456         else
 457                 kstat_cpu(cpu).irqs[EXTINT_EMS]++;
 458         /*
 459          * handle bit signal external calls
 460          */
 461         bits = xchg(&pcpu_devices[cpu].ec_mask, 0);
 462
 463         if (test_bit(ec_stop_cpu, &bits))
 464                 smp_stop_cpu();
 465
 466         if (test_bit(ec_schedule, &bits))
 467                 scheduler_ipi();
 468
 469         if (test_bit(ec_call_function, &bits))
 470                 generic_smp_call_function_interrupt();
 471
 472         if (test_bit(ec_call_function_single, &bits))
 473                 generic_smp_call_function_single_interrupt();
 474
 475 }
 476
 477 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 478 {
 479         int cpu;
 480
 481         for_each_cpu(cpu, mask)
 482                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function);
 483 }
 484
 485 void arch_send_call_function_single_ipi(int cpu)
 486 {
 487         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 488 }
 489
 490 #ifndef CONFIG_64BIT
 491 /*
 492  * this function sends a 'purge tlb' signal to another CPU.
 493  */
 494 static void smp_ptlb_callback(void *info)
 495 {
 496         __tlb_flush_local();
 497 }
 498
 499 void smp_ptlb_all(void)
 500 {
 501         on_each_cpu(smp_ptlb_callback, NULL, 1);
 502 }
 503 EXPORT_SYMBOL(smp_ptlb_all);
 504 #endif /* ! CONFIG_64BIT */
 505
 506 /*
 507  * this function sends a 'reschedule' IPI to another CPU.
 508  * it goes straight through and wastes no time serializing
 509  * anything. Worst case is that we lose a reschedule ...
 510  */
 511 void smp_send_reschedule(int cpu)
 512 {
 513         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 514 }
 515
 516 /*
 517  * parameter area for the set/clear control bit callbacks
 518  */
 519 struct ec_creg_mask_parms {
 520         unsigned long orval;
 521         unsigned long andval;
 522         int cr;
 523 };
 524
 525 /*
 526  * callback for setting/clearing control bits
 527  */
 528 static void smp_ctl_bit_callback(void *info)
 529 {
 530         struct ec_creg_mask_parms *pp = info;
 531         unsigned long cregs[16];
 532
 533         __ctl_store(cregs, 0, 15);
 534         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 535         __ctl_load(cregs, 0, 15);
 536 }
 537
 538 /*
 539  * Set a bit in a control register of all cpus
 540  */
 541 void smp_ctl_set_bit(int cr, int bit)
 542 {
 543         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 544
 545         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 546 }
 547 EXPORT_SYMBOL(smp_ctl_set_bit);
 548
 549 /*
 550  * Clear a bit in a control register of all cpus
 551  */
 552 void smp_ctl_clear_bit(int cr, int bit)
 553 {
 554         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 555
 556         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 557 }
 558 EXPORT_SYMBOL(smp_ctl_clear_bit);
 559
 560 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
 561
 562 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
 563 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
 564
 565 static void __init smp_get_save_area(int cpu, u16 address)
 566 {
 567         void *lc = pcpu_devices[0].lowcore;
 568         struct save_area *save_area;
 569
 570         if (is_kdump_kernel())
 571                 return;
 572         if (!OLDMEM_BASE && (address == boot_cpu_address ||
 573                              ipl_info.type != IPL_TYPE_FCP_DUMP))
 574                 return;
 575         if (cpu >= NR_CPUS) {
 576                 pr_warning("CPU %i exceeds the maximum %i and is excluded "
 577                            "from the dump\n", cpu, NR_CPUS - 1);
 578                 return;
 579         }
 580         save_area = kmalloc(sizeof(struct save_area), GFP_KERNEL);
 581         if (!save_area)
 582                 panic("could not allocate memory for save area\n");
 583         zfcpdump_save_areas[cpu] = save_area;
 584 #ifdef CONFIG_CRASH_DUMP
 585         if (address == boot_cpu_address) {
 586                 /* Copy the registers of the boot cpu. */
 587                 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
 588                                  SAVE_AREA_BASE - PAGE_SIZE, 0);
 589                 return;
 590         }
 591 #endif
 592         /* Get the registers of a non-boot cpu. */
 593         __pcpu_sigp_relax(address, sigp_stop_and_store_status, 0, NULL);
 594         memcpy_real(save_area, lc + SAVE_AREA_BASE, sizeof(*save_area));
 595 }
 596
 597 int smp_store_status(int cpu)
 598 {
 599         struct pcpu *pcpu;
 600
 601         pcpu = pcpu_devices + cpu;
 602         if (__pcpu_sigp_relax(pcpu->address, sigp_stop_and_store_status,
 603                               0, NULL) != sigp_order_code_accepted)
 604                 return -EIO;
 605         return 0;
 606 }
 607
 608 #else /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
 609
 610 static inline void smp_get_save_area(int cpu, u16 address) { }
 611
 612 #endif /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
 613
 614 static struct sclp_cpu_info *smp_get_cpu_info(void)
 615 {
 616         static int use_sigp_detection;
 617         struct sclp_cpu_info *info;
 618         int address;
 619
 620         info = kzalloc(sizeof(*info), GFP_KERNEL);
 621         if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
 622                 use_sigp_detection = 1;
 623                 for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
 624                         if (__pcpu_sigp_relax(address, sigp_sense, 0, NULL) ==
 625                             sigp_not_operational)
 626                                 continue;
 627                         info->cpu[info->configured].address = address;
 628                         info->configured++;
 629                 }
 630                 info->combined = info->configured;
 631         }
 632         return info;
 633 }
 634
 635 static int __devinit smp_add_present_cpu(int cpu);
 636
 637 static int __devinit __smp_rescan_cpus(struct sclp_cpu_info *info,
 638                                        int sysfs_add)
 639 {
 640         struct pcpu *pcpu;
 641         cpumask_t avail;
 642         int cpu, nr, i;
 643
 644         nr = 0;
 645         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 646         cpu = cpumask_first(&avail);
 647         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 648                 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
 649                         continue;
 650                 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
 651                         continue;
 652                 pcpu = pcpu_devices + cpu;
 653                 pcpu->address = info->cpu[i].address;
 654                 pcpu->state = (cpu >= info->configured) ?
 655                         CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 656                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 657                 set_cpu_present(cpu, true);
 658                 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 659                         set_cpu_present(cpu, false);
 660                 else
 661                         nr++;
 662                 cpu = cpumask_next(cpu, &avail);
 663         }
 664         return nr;
 665 }
 666
 667 static void __init smp_detect_cpus(void)
 668 {
 669         unsigned int cpu, c_cpus, s_cpus;
 670         struct sclp_cpu_info *info;
 671
 672         info = smp_get_cpu_info();
 673         if (!info)
 674                 panic("smp_detect_cpus failed to allocate memory\n");
 675         if (info->has_cpu_type) {
 676                 for (cpu = 0; cpu < info->combined; cpu++) {
 677                         if (info->cpu[cpu].address != boot_cpu_address)
 678                                 continue;
 679                         /* The boot cpu dictates the cpu type. */
 680                         boot_cpu_type = info->cpu[cpu].type;
 681                         break;
 682                 }
 683         }
 684         c_cpus = s_cpus = 0;
 685         for (cpu = 0; cpu < info->combined; cpu++) {
 686                 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
 687                         continue;
 688                 if (cpu < info->configured) {
 689                         smp_get_save_area(c_cpus, info->cpu[cpu].address);
 690                         c_cpus++;
 691                 } else
 692                         s_cpus++;
 693         }
 694         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 695         get_online_cpus();
 696         __smp_rescan_cpus(info, 0);
 697         put_online_cpus();
 698         kfree(info);
 699 }
 700
 701 /*
 702  *      Activate a secondary processor.
 703  */
 704 static void __cpuinit smp_start_secondary(void *cpuvoid)
 705 {
 706         S390_lowcore.last_update_clock = get_clock();
 707         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 708         S390_lowcore.restart_fn = (unsigned long) do_restart;
 709         S390_lowcore.restart_data = 0;
 710         S390_lowcore.restart_source = -1UL;
 711         restore_access_regs(S390_lowcore.access_regs_save_area);
 712         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 713         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
 714         cpu_init();
 715         preempt_disable();
 716         init_cpu_timer();
 717         init_cpu_vtimer();
 718         pfault_init();
 719         notify_cpu_starting(smp_processor_id());
 720         ipi_call_lock();
 721         set_cpu_online(smp_processor_id(), true);
 722         ipi_call_unlock();
 723         local_irq_enable();
 724         /* cpu_idle will call schedule for us */
 725         cpu_idle();
 726 }
 727
 728 /* Upping and downing of CPUs */
 729 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 730 {
 731         struct pcpu *pcpu;
 732         int rc;
 733
 734         pcpu = pcpu_devices + cpu;
 735         if (pcpu->state != CPU_STATE_CONFIGURED)
 736                 return -EIO;
 737         if (pcpu_sigp_retry(pcpu, sigp_initial_cpu_reset, 0) !=
 738             sigp_order_code_accepted)
 739                 return -EIO;
 740
 741         rc = pcpu_alloc_lowcore(pcpu, cpu);
 742         if (rc)
 743                 return rc;
 744         pcpu_prepare_secondary(pcpu, cpu);
 745         pcpu_attach_task(pcpu, tidle);
 746         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 747         while (!cpu_online(cpu))
 748                 cpu_relax();
 749         return 0;
 750 }
 751
 752 static int __init setup_possible_cpus(char *s)
 753 {
 754         int max, cpu;
 755
 756         if (kstrtoint(s, 0, &max) < 0)
 757                 return 0;
 758         init_cpu_possible(cpumask_of(0));
 759         for (cpu = 1; cpu < max && cpu < nr_cpu_ids; cpu++)
 760                 set_cpu_possible(cpu, true);
 761         return 0;
 762 }
 763 early_param("possible_cpus", setup_possible_cpus);
 764
 765 #ifdef CONFIG_HOTPLUG_CPU
 766
 767 int __cpu_disable(void)
 768 {
 769         unsigned long cregs[16];
 770
 771         set_cpu_online(smp_processor_id(), false);
 772         /* Disable pseudo page faults on this cpu. */
 773         pfault_fini();
 774         /* Disable interrupt sources via control register. */
 775         __ctl_store(cregs, 0, 15);
 776         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 777         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 778         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 779         __ctl_load(cregs, 0, 15);
 780         return 0;
 781 }
 782
 783 void __cpu_die(unsigned int cpu)
 784 {
 785         struct pcpu *pcpu;
 786
 787         /* Wait until target cpu is down */
 788         pcpu = pcpu_devices + cpu;
 789         while (!pcpu_stopped(pcpu))
 790                 cpu_relax();
 791         pcpu_free_lowcore(pcpu);
 792         atomic_dec(&init_mm.context.attach_count);
 793 }
 794
 795 void __noreturn cpu_die(void)
 796 {
 797         idle_task_exit();
 798         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), sigp_stop, 0);
 799         for (;;) ;
 800 }
 801
 802 #endif /* CONFIG_HOTPLUG_CPU */
 803
 804 void __init smp_prepare_cpus(unsigned int max_cpus)
 805 {
 806         /* request the 0x1201 emergency signal external interrupt */
 807         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
 808                 panic("Couldn't request external interrupt 0x1201");
 809         /* request the 0x1202 external call external interrupt */
 810         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
 811                 panic("Couldn't request external interrupt 0x1202");
 812         smp_detect_cpus();
 813 }
 814
 815 void __init smp_prepare_boot_cpu(void)
 816 {
 817         struct pcpu *pcpu = pcpu_devices;
 818
 819         boot_cpu_address = stap();
 820         pcpu->state = CPU_STATE_CONFIGURED;
 821         pcpu->address = boot_cpu_address;
 822         pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
 823         pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE;
 824         pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE;
 825         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 826         cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 827         set_cpu_present(0, true);
 828         set_cpu_online(0, true);
 829 }
 830
 831 void __init smp_cpus_done(unsigned int max_cpus)
 832 {
 833 }
 834
 835 void __init smp_setup_processor_id(void)
 836 {
 837         S390_lowcore.cpu_nr = 0;
 838 }
 839
 840 /*
 841  * the frequency of the profiling timer can be changed
 842  * by writing a multiplier value into /proc/profile.
 843  *
 844  * usually you want to run this on all CPUs ;)
 845  */
 846 int setup_profiling_timer(unsigned int multiplier)
 847 {
 848         return 0;
 849 }
 850
 851 #ifdef CONFIG_HOTPLUG_CPU
 852 static ssize_t cpu_configure_show(struct device *dev,
 853                                   struct device_attribute *attr, char *buf)
 854 {
 855         ssize_t count;
 856
 857         mutex_lock(&smp_cpu_state_mutex);
 858         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 859         mutex_unlock(&smp_cpu_state_mutex);
 860         return count;
 861 }
 862
 863 static ssize_t cpu_configure_store(struct device *dev,
 864                                    struct device_attribute *attr,
 865                                    const char *buf, size_t count)
 866 {
 867         struct pcpu *pcpu;
 868         int cpu, val, rc;
 869         char delim;
 870
 871         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 872                 return -EINVAL;
 873         if (val != 0 && val != 1)
 874                 return -EINVAL;
 875         get_online_cpus();
 876         mutex_lock(&smp_cpu_state_mutex);
 877         rc = -EBUSY;
 878         /* disallow configuration changes of online cpus and cpu 0 */
 879         cpu = dev->id;
 880         if (cpu_online(cpu) || cpu == 0)
 881                 goto out;
 882         pcpu = pcpu_devices + cpu;
 883         rc = 0;
 884         switch (val) {
 885         case 0:
 886                 if (pcpu->state != CPU_STATE_CONFIGURED)
 887                         break;
 888                 rc = sclp_cpu_deconfigure(pcpu->address);
 889                 if (rc)
 890                         break;
 891                 pcpu->state = CPU_STATE_STANDBY;
 892                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 893                 topology_expect_change();
 894                 break;
 895         case 1:
 896                 if (pcpu->state != CPU_STATE_STANDBY)
 897                         break;
 898                 rc = sclp_cpu_configure(pcpu->address);
 899                 if (rc)
 900                         break;
 901                 pcpu->state = CPU_STATE_CONFIGURED;
 902                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 903                 topology_expect_change();
 904                 break;
 905         default:
 906                 break;
 907         }
 908 out:
 909         mutex_unlock(&smp_cpu_state_mutex);
 910         put_online_cpus();
 911         return rc ? rc : count;
 912 }
 913 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
 914 #endif /* CONFIG_HOTPLUG_CPU */
 915
 916 static ssize_t show_cpu_address(struct device *dev,
 917                                 struct device_attribute *attr, char *buf)
 918 {
 919         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
 920 }
 921 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
 922
 923 static struct attribute *cpu_common_attrs[] = {
 924 #ifdef CONFIG_HOTPLUG_CPU
 925         &dev_attr_configure.attr,
 926 #endif
 927         &dev_attr_address.attr,
 928         NULL,
 929 };
 930
 931 static struct attribute_group cpu_common_attr_group = {
 932         .attrs = cpu_common_attrs,
 933 };
 934
 935 static ssize_t show_idle_count(struct device *dev,
 936                                 struct device_attribute *attr, char *buf)
 937 {
 938         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
 939         unsigned long long idle_count;
 940         unsigned int sequence;
 941
 942         do {
 943                 sequence = ACCESS_ONCE(idle->sequence);
 944                 idle_count = ACCESS_ONCE(idle->idle_count);
 945                 if (ACCESS_ONCE(idle->idle_enter))
 946                         idle_count++;
 947         } while ((sequence & 1) || (idle->sequence != sequence));
 948         return sprintf(buf, "%llu\n", idle_count);
 949 }
 950 static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
 951
 952 static ssize_t show_idle_time(struct device *dev,
 953                                 struct device_attribute *attr, char *buf)
 954 {
 955         struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
 956         unsigned long long now, idle_time, idle_enter, idle_exit;
 957         unsigned int sequence;
 958
 959         do {
 960                 now = get_clock();
 961                 sequence = ACCESS_ONCE(idle->sequence);
 962                 idle_time = ACCESS_ONCE(idle->idle_time);
 963                 idle_enter = ACCESS_ONCE(idle->idle_enter);
 964                 idle_exit = ACCESS_ONCE(idle->idle_exit);
 965         } while ((sequence & 1) || (idle->sequence != sequence));
 966         idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
 967         return sprintf(buf, "%llu\n", idle_time >> 12);
 968 }
 969 static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
 970
 971 static struct attribute *cpu_online_attrs[] = {
 972         &dev_attr_idle_count.attr,
 973         &dev_attr_idle_time_us.attr,
 974         NULL,
 975 };
 976
 977 static struct attribute_group cpu_online_attr_group = {
 978         .attrs = cpu_online_attrs,
 979 };
 980
 981 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
 982                                     unsigned long action, void *hcpu)
 983 {
 984         unsigned int cpu = (unsigned int)(long)hcpu;
 985         struct cpu *c = &pcpu_devices[cpu].cpu;
 986         struct device *s = &c->dev;
 987         struct s390_idle_data *idle;
 988         int err = 0;
 989
 990         switch (action) {
 991         case CPU_ONLINE:
 992         case CPU_ONLINE_FROZEN:
 993                 idle = &per_cpu(s390_idle, cpu);
 994                 memset(idle, 0, sizeof(struct s390_idle_data));
 995                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
 996                 break;
 997         case CPU_DEAD:
 998         case CPU_DEAD_FROZEN:
 999                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1000                 break;
1001         }
1002         return notifier_from_errno(err);
1003 }
1004
1005 static struct notifier_block __cpuinitdata smp_cpu_nb = {
1006         .notifier_call = smp_cpu_notify,
1007 };
1008
1009 static int __devinit smp_add_present_cpu(int cpu)
1010 {
1011         struct cpu *c = &pcpu_devices[cpu].cpu;
1012         struct device *s = &c->dev;
1013         int rc;
1014
1015         c->hotpluggable = 1;
1016         rc = register_cpu(c, cpu);
1017         if (rc)
1018                 goto out;
1019         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1020         if (rc)
1021                 goto out_cpu;
1022         if (cpu_online(cpu)) {
1023                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1024                 if (rc)
1025                         goto out_online;
1026         }
1027         rc = topology_cpu_init(c);
1028         if (rc)
1029                 goto out_topology;
1030         return 0;
1031
1032 out_topology:
1033         if (cpu_online(cpu))
1034                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1035 out_online:
1036         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1037 out_cpu:
1038 #ifdef CONFIG_HOTPLUG_CPU
1039         unregister_cpu(c);
1040 #endif
1041 out:
1042         return rc;
1043 }
1044
1045 #ifdef CONFIG_HOTPLUG_CPU
1046
1047 int __ref smp_rescan_cpus(void)
1048 {
1049         struct sclp_cpu_info *info;
1050         int nr;
1051
1052         info = smp_get_cpu_info();
1053         if (!info)
1054                 return -ENOMEM;
1055         get_online_cpus();
1056         mutex_lock(&smp_cpu_state_mutex);
1057         nr = __smp_rescan_cpus(info, 1);
1058         mutex_unlock(&smp_cpu_state_mutex);
1059         put_online_cpus();
1060         kfree(info);
1061         if (nr)
1062                 topology_schedule_update();
1063         return 0;
1064 }
1065
1066 static ssize_t __ref rescan_store(struct device *dev,
1067                                   struct device_attribute *attr,
1068                                   const char *buf,
1069                                   size_t count)
1070 {
1071         int rc;
1072
1073         rc = smp_rescan_cpus();
1074         return rc ? rc : count;
1075 }
1076 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1077 #endif /* CONFIG_HOTPLUG_CPU */
1078
1079 static int __init s390_smp_init(void)
1080 {
1081         int cpu, rc;
1082
1083         register_cpu_notifier(&smp_cpu_nb);
1084 #ifdef CONFIG_HOTPLUG_CPU
1085         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1086         if (rc)
1087                 return rc;
1088 #endif
1089         for_each_present_cpu(cpu) {
1090                 rc = smp_add_present_cpu(cpu);
1091                 if (rc)
1092                         return rc;
1093         }
1094         return 0;
1095 }
1096 subsys_initcall(s390_smp_init);