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