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/bootmem.h>
  23 #include <linux/export.h>
  24 #include <linux/init.h>
  25 #include <linux/mm.h>
  26 #include <linux/err.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/kernel_stat.h>
  29 #include <linux/delay.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/irqflags.h>
  32 #include <linux/cpu.h>
  33 #include <linux/slab.h>
  34 #include <linux/sched/hotplug.h>
  35 #include <linux/sched/task_stack.h>
  36 #include <linux/crash_dump.h>
  37 #include <linux/memblock.h>
  38 #include <asm/asm-offsets.h>
  39 #include <asm/diag.h>
  40 #include <asm/switch_to.h>
  41 #include <asm/facility.h>
  42 #include <asm/ipl.h>
  43 #include <asm/setup.h>
  44 #include <asm/irq.h>
  45 #include <asm/tlbflush.h>
  46 #include <asm/vtimer.h>
  47 #include <asm/lowcore.h>
  48 #include <asm/sclp.h>
  49 #include <asm/vdso.h>
  50 #include <asm/debug.h>
  51 #include <asm/os_info.h>
  52 #include <asm/sigp.h>
  53 #include <asm/idle.h>
  54 #include "entry.h"
  55
  56 enum {
  57         ec_schedule = 0,
  58         ec_call_function_single,
  59         ec_stop_cpu,
  60 };
  61
  62 enum {
  63         CPU_STATE_STANDBY,
  64         CPU_STATE_CONFIGURED,
  65 };
  66
  67 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  68
  69 struct pcpu {
  70         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  71         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  72         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  73         signed char state;              /* physical cpu state */
  74         signed char polarization;       /* physical polarization */
  75         u16 address;                    /* physical cpu address */
  76 };
  77
  78 static u8 boot_core_type;
  79 static struct pcpu pcpu_devices[NR_CPUS];
  80
  81 unsigned int smp_cpu_mt_shift;
  82 EXPORT_SYMBOL(smp_cpu_mt_shift);
  83
  84 unsigned int smp_cpu_mtid;
  85 EXPORT_SYMBOL(smp_cpu_mtid);
  86
  87 #ifdef CONFIG_CRASH_DUMP
  88 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  89 #endif
  90
  91 static unsigned int smp_max_threads __initdata = -1U;
  92
  93 static int __init early_nosmt(char *s)
  94 {
  95         smp_max_threads = 1;
  96         return 0;
  97 }
  98 early_param("nosmt", early_nosmt);
  99
 100 static int __init early_smt(char *s)
 101 {
 102         get_option(&s, &smp_max_threads);
 103         return 0;
 104 }
 105 early_param("smt", early_smt);
 106
 107 /*
 108  * The smp_cpu_state_mutex must be held when changing the state or polarization
 109  * member of a pcpu data structure within the pcpu_devices arreay.
 110  */
 111 DEFINE_MUTEX(smp_cpu_state_mutex);
 112
 113 /*
 114  * Signal processor helper functions.
 115  */
 116 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 117 {
 118         int cc;
 119
 120         while (1) {
 121                 cc = __pcpu_sigp(addr, order, parm, NULL);
 122                 if (cc != SIGP_CC_BUSY)
 123                         return cc;
 124                 cpu_relax();
 125         }
 126 }
 127
 128 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 129 {
 130         int cc, retry;
 131
 132         for (retry = 0; ; retry++) {
 133                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 134                 if (cc != SIGP_CC_BUSY)
 135                         break;
 136                 if (retry >= 3)
 137                         udelay(10);
 138         }
 139         return cc;
 140 }
 141
 142 static inline int pcpu_stopped(struct pcpu *pcpu)
 143 {
 144         u32 uninitialized_var(status);
 145
 146         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 147                         0, &status) != SIGP_CC_STATUS_STORED)
 148                 return 0;
 149         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 150 }
 151
 152 static inline int pcpu_running(struct pcpu *pcpu)
 153 {
 154         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 155                         0, NULL) != SIGP_CC_STATUS_STORED)
 156                 return 1;
 157         /* Status stored condition code is equivalent to cpu not running. */
 158         return 0;
 159 }
 160
 161 /*
 162  * Find struct pcpu by cpu address.
 163  */
 164 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 165 {
 166         int cpu;
 167
 168         for_each_cpu(cpu, mask)
 169                 if (pcpu_devices[cpu].address == address)
 170                         return pcpu_devices + cpu;
 171         return NULL;
 172 }
 173
 174 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 175 {
 176         int order;
 177
 178         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 179                 return;
 180         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 181         pcpu->ec_clk = get_tod_clock_fast();
 182         pcpu_sigp_retry(pcpu, order, 0);
 183 }
 184
 185 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 186 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 187
 188 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 189 {
 190         unsigned long async_stack, panic_stack;
 191         struct lowcore *lc;
 192
 193         if (pcpu != &pcpu_devices[0]) {
 194                 pcpu->lowcore = (struct lowcore *)
 195                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 196                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 197                 panic_stack = __get_free_page(GFP_KERNEL);
 198                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 199                         goto out;
 200         } else {
 201                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 202                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 203         }
 204         lc = pcpu->lowcore;
 205         memcpy(lc, &S390_lowcore, 512);
 206         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 207         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 208         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 209         lc->cpu_nr = cpu;
 210         lc->spinlock_lockval = arch_spin_lockval(cpu);
 211         if (MACHINE_HAS_VX)
 212                 lc->vector_save_area_addr =
 213                         (unsigned long) &lc->vector_save_area;
 214         if (vdso_alloc_per_cpu(lc))
 215                 goto out;
 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(panic_stack);
 222                 free_pages(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         vdso_free_per_cpu(pcpu->lowcore);
 235         if (pcpu == &pcpu_devices[0])
 236                 return;
 237         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 238         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 239         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 240 }
 241
 242 #endif /* CONFIG_HOTPLUG_CPU */
 243
 244 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 245 {
 246         struct lowcore *lc = pcpu->lowcore;
 247
 248         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 249         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 250         lc->cpu_nr = cpu;
 251         lc->spinlock_lockval = arch_spin_lockval(cpu);
 252         lc->percpu_offset = __per_cpu_offset[cpu];
 253         lc->kernel_asce = S390_lowcore.kernel_asce;
 254         lc->machine_flags = S390_lowcore.machine_flags;
 255         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 256         __ctl_store(lc->cregs_save_area, 0, 15);
 257         save_access_regs((unsigned int *) lc->access_regs_save_area);
 258         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 259                MAX_FACILITY_BIT/8);
 260 }
 261
 262 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 263 {
 264         struct lowcore *lc = pcpu->lowcore;
 265
 266         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 267                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 268         lc->current_task = (unsigned long) tsk;
 269         lc->lpp = LPP_MAGIC;
 270         lc->current_pid = tsk->pid;
 271         lc->user_timer = tsk->thread.user_timer;
 272         lc->system_timer = tsk->thread.system_timer;
 273         lc->steal_timer = 0;
 274 }
 275
 276 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 277 {
 278         struct lowcore *lc = pcpu->lowcore;
 279
 280         lc->restart_stack = lc->kernel_stack;
 281         lc->restart_fn = (unsigned long) func;
 282         lc->restart_data = (unsigned long) data;
 283         lc->restart_source = -1UL;
 284         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 285 }
 286
 287 /*
 288  * Call function via PSW restart on pcpu and stop the current cpu.
 289  */
 290 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 291                           void *data, unsigned long stack)
 292 {
 293         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 294         unsigned long source_cpu = stap();
 295
 296         __load_psw_mask(PSW_KERNEL_BITS);
 297         if (pcpu->address == source_cpu)
 298                 func(data);     /* should not return */
 299         /* Stop target cpu (if func returns this stops the current cpu). */
 300         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 301         /* Restart func on the target cpu and stop the current cpu. */
 302         mem_assign_absolute(lc->restart_stack, stack);
 303         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 304         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 305         mem_assign_absolute(lc->restart_source, source_cpu);
 306         asm volatile(
 307                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 308                 "       brc     2,0b    # busy, try again\n"
 309                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 310                 "       brc     2,1b    # busy, try again\n"
 311                 : : "d" (pcpu->address), "d" (source_cpu),
 312                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 313                 : "0", "1", "cc");
 314         for (;;) ;
 315 }
 316
 317 /*
 318  * Enable additional logical cpus for multi-threading.
 319  */
 320 static int pcpu_set_smt(unsigned int mtid)
 321 {
 322         int cc;
 323
 324         if (smp_cpu_mtid == mtid)
 325                 return 0;
 326         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 327         if (cc == 0) {
 328                 smp_cpu_mtid = mtid;
 329                 smp_cpu_mt_shift = 0;
 330                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 331                         smp_cpu_mt_shift++;
 332                 pcpu_devices[0].address = stap();
 333         }
 334         return cc;
 335 }
 336
 337 /*
 338  * Call function on an online CPU.
 339  */
 340 void smp_call_online_cpu(void (*func)(void *), void *data)
 341 {
 342         struct pcpu *pcpu;
 343
 344         /* Use the current cpu if it is online. */
 345         pcpu = pcpu_find_address(cpu_online_mask, stap());
 346         if (!pcpu)
 347                 /* Use the first online cpu. */
 348                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 349         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 350 }
 351
 352 /*
 353  * Call function on the ipl CPU.
 354  */
 355 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 356 {
 357         pcpu_delegate(&pcpu_devices[0], func, data,
 358                       pcpu_devices->lowcore->panic_stack -
 359                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 360 }
 361
 362 int smp_find_processor_id(u16 address)
 363 {
 364         int cpu;
 365
 366         for_each_present_cpu(cpu)
 367                 if (pcpu_devices[cpu].address == address)
 368                         return cpu;
 369         return -1;
 370 }
 371
 372 bool arch_vcpu_is_preempted(int cpu)
 373 {
 374         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 375                 return false;
 376         if (pcpu_running(pcpu_devices + cpu))
 377                 return false;
 378         return true;
 379 }
 380 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 381
 382 void smp_yield_cpu(int cpu)
 383 {
 384         if (MACHINE_HAS_DIAG9C) {
 385                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 386                 asm volatile("diag %0,0,0x9c"
 387                              : : "d" (pcpu_devices[cpu].address));
 388         } else if (MACHINE_HAS_DIAG44) {
 389                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 390                 asm volatile("diag 0,0,0x44");
 391         }
 392 }
 393
 394 /*
 395  * Send cpus emergency shutdown signal. This gives the cpus the
 396  * opportunity to complete outstanding interrupts.
 397  */
 398 static void smp_emergency_stop(cpumask_t *cpumask)
 399 {
 400         u64 end;
 401         int cpu;
 402
 403         end = get_tod_clock() + (1000000UL << 12);
 404         for_each_cpu(cpu, cpumask) {
 405                 struct pcpu *pcpu = pcpu_devices + cpu;
 406                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 407                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 408                                    0, NULL) == SIGP_CC_BUSY &&
 409                        get_tod_clock() < end)
 410                         cpu_relax();
 411         }
 412         while (get_tod_clock() < end) {
 413                 for_each_cpu(cpu, cpumask)
 414                         if (pcpu_stopped(pcpu_devices + cpu))
 415                                 cpumask_clear_cpu(cpu, cpumask);
 416                 if (cpumask_empty(cpumask))
 417                         break;
 418                 cpu_relax();
 419         }
 420 }
 421
 422 /*
 423  * Stop all cpus but the current one.
 424  */
 425 void smp_send_stop(void)
 426 {
 427         cpumask_t cpumask;
 428         int cpu;
 429
 430         /* Disable all interrupts/machine checks */
 431         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 432         trace_hardirqs_off();
 433
 434         debug_set_critical();
 435         cpumask_copy(&cpumask, cpu_online_mask);
 436         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 437
 438         if (oops_in_progress)
 439                 smp_emergency_stop(&cpumask);
 440
 441         /* stop all processors */
 442         for_each_cpu(cpu, &cpumask) {
 443                 struct pcpu *pcpu = pcpu_devices + cpu;
 444                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 445                 while (!pcpu_stopped(pcpu))
 446                         cpu_relax();
 447         }
 448 }
 449
 450 /*
 451  * This is the main routine where commands issued by other
 452  * cpus are handled.
 453  */
 454 static void smp_handle_ext_call(void)
 455 {
 456         unsigned long bits;
 457
 458         /* handle bit signal external calls */
 459         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 460         if (test_bit(ec_stop_cpu, &bits))
 461                 smp_stop_cpu();
 462         if (test_bit(ec_schedule, &bits))
 463                 scheduler_ipi();
 464         if (test_bit(ec_call_function_single, &bits))
 465                 generic_smp_call_function_single_interrupt();
 466 }
 467
 468 static void do_ext_call_interrupt(struct ext_code ext_code,
 469                                   unsigned int param32, unsigned long param64)
 470 {
 471         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 472         smp_handle_ext_call();
 473 }
 474
 475 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 476 {
 477         int cpu;
 478
 479         for_each_cpu(cpu, mask)
 480                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 481 }
 482
 483 void arch_send_call_function_single_ipi(int cpu)
 484 {
 485         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 486 }
 487
 488 /*
 489  * this function sends a 'reschedule' IPI to another CPU.
 490  * it goes straight through and wastes no time serializing
 491  * anything. Worst case is that we lose a reschedule ...
 492  */
 493 void smp_send_reschedule(int cpu)
 494 {
 495         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 496 }
 497
 498 /*
 499  * parameter area for the set/clear control bit callbacks
 500  */
 501 struct ec_creg_mask_parms {
 502         unsigned long orval;
 503         unsigned long andval;
 504         int cr;
 505 };
 506
 507 /*
 508  * callback for setting/clearing control bits
 509  */
 510 static void smp_ctl_bit_callback(void *info)
 511 {
 512         struct ec_creg_mask_parms *pp = info;
 513         unsigned long cregs[16];
 514
 515         __ctl_store(cregs, 0, 15);
 516         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 517         __ctl_load(cregs, 0, 15);
 518 }
 519
 520 /*
 521  * Set a bit in a control register of all cpus
 522  */
 523 void smp_ctl_set_bit(int cr, int bit)
 524 {
 525         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 526
 527         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 528 }
 529 EXPORT_SYMBOL(smp_ctl_set_bit);
 530
 531 /*
 532  * Clear a bit in a control register of all cpus
 533  */
 534 void smp_ctl_clear_bit(int cr, int bit)
 535 {
 536         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 537
 538         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 539 }
 540 EXPORT_SYMBOL(smp_ctl_clear_bit);
 541
 542 #ifdef CONFIG_CRASH_DUMP
 543
 544 int smp_store_status(int cpu)
 545 {
 546         struct pcpu *pcpu = pcpu_devices + cpu;
 547         unsigned long pa;
 548
 549         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 550         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 551                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 552                 return -EIO;
 553         if (!MACHINE_HAS_VX)
 554                 return 0;
 555         pa = __pa(pcpu->lowcore->vector_save_area_addr);
 556         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 557                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 558                 return -EIO;
 559         return 0;
 560 }
 561
 562 /*
 563  * Collect CPU state of the previous, crashed system.
 564  * There are four cases:
 565  * 1) standard zfcp dump
 566  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 567  *    The state for all CPUs except the boot CPU needs to be collected
 568  *    with sigp stop-and-store-status. The boot CPU state is located in
 569  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 570  *    will copy the boot CPU state from the HSA.
 571  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 572  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 573  *    The state for all CPUs except the boot CPU needs to be collected
 574  *    with sigp stop-and-store-status. The firmware or the boot-loader
 575  *    stored the registers of the boot CPU in the absolute lowcore in the
 576  *    memory of the old system.
 577  * 3) kdump and the old kernel did not store the CPU state,
 578  *    or stand-alone kdump for DASD
 579  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 580  *    The state for all CPUs except the boot CPU needs to be collected
 581  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 582  *    stored the registers of the boot CPU in the memory of the old system.
 583  * 4) kdump and the old kernel stored the CPU state
 584  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 585  *    This case does not exist for s390 anymore, setup_arch explicitly
 586  *    deactivates the elfcorehdr= kernel parameter
 587  */
 588 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 589                                      bool is_boot_cpu, unsigned long page)
 590 {
 591         __vector128 *vxrs = (__vector128 *) page;
 592
 593         if (is_boot_cpu)
 594                 vxrs = boot_cpu_vector_save_area;
 595         else
 596                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 597         save_area_add_vxrs(sa, vxrs);
 598 }
 599
 600 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 601                                      bool is_boot_cpu, unsigned long page)
 602 {
 603         void *regs = (void *) page;
 604
 605         if (is_boot_cpu)
 606                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 607         else
 608                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 609         save_area_add_regs(sa, regs);
 610 }
 611
 612 void __init smp_save_dump_cpus(void)
 613 {
 614         int addr, boot_cpu_addr, max_cpu_addr;
 615         struct save_area *sa;
 616         unsigned long page;
 617         bool is_boot_cpu;
 618
 619         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 620                 /* No previous system present, normal boot. */
 621                 return;
 622         /* Allocate a page as dumping area for the store status sigps */
 623         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 624         /* Set multi-threading state to the previous system. */
 625         pcpu_set_smt(sclp.mtid_prev);
 626         boot_cpu_addr = stap();
 627         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 628         for (addr = 0; addr <= max_cpu_addr; addr++) {
 629                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 630                     SIGP_CC_NOT_OPERATIONAL)
 631                         continue;
 632                 is_boot_cpu = (addr == boot_cpu_addr);
 633                 /* Allocate save area */
 634                 sa = save_area_alloc(is_boot_cpu);
 635                 if (!sa)
 636                         panic("could not allocate memory for save area\n");
 637                 if (MACHINE_HAS_VX)
 638                         /* Get the vector registers */
 639                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 640                 /*
 641                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 642                  * of the boot CPU are stored in the HSA. To retrieve
 643                  * these registers an SCLP request is required which is
 644                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 645                  */
 646                 if (!is_boot_cpu || OLDMEM_BASE)
 647                         /* Get the CPU registers */
 648                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 649         }
 650         memblock_free(page, PAGE_SIZE);
 651         diag308_reset();
 652         pcpu_set_smt(0);
 653 }
 654 #endif /* CONFIG_CRASH_DUMP */
 655
 656 void smp_cpu_set_polarization(int cpu, int val)
 657 {
 658         pcpu_devices[cpu].polarization = val;
 659 }
 660
 661 int smp_cpu_get_polarization(int cpu)
 662 {
 663         return pcpu_devices[cpu].polarization;
 664 }
 665
 666 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 667 {
 668         static int use_sigp_detection;
 669         int address;
 670
 671         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 672                 use_sigp_detection = 1;
 673                 for (address = 0;
 674                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 675                      address += (1U << smp_cpu_mt_shift)) {
 676                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 677                             SIGP_CC_NOT_OPERATIONAL)
 678                                 continue;
 679                         info->core[info->configured].core_id =
 680                                 address >> smp_cpu_mt_shift;
 681                         info->configured++;
 682                 }
 683                 info->combined = info->configured;
 684         }
 685 }
 686
 687 static int smp_add_present_cpu(int cpu);
 688
 689 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 690 {
 691         struct pcpu *pcpu;
 692         cpumask_t avail;
 693         int cpu, nr, i, j;
 694         u16 address;
 695
 696         nr = 0;
 697         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 698         cpu = cpumask_first(&avail);
 699         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 700                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 701                         continue;
 702                 address = info->core[i].core_id << smp_cpu_mt_shift;
 703                 for (j = 0; j <= smp_cpu_mtid; j++) {
 704                         if (pcpu_find_address(cpu_present_mask, address + j))
 705                                 continue;
 706                         pcpu = pcpu_devices + cpu;
 707                         pcpu->address = address + j;
 708                         pcpu->state =
 709                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 710                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 711                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 712                         set_cpu_present(cpu, true);
 713                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 714                                 set_cpu_present(cpu, false);
 715                         else
 716                                 nr++;
 717                         cpu = cpumask_next(cpu, &avail);
 718                         if (cpu >= nr_cpu_ids)
 719                                 break;
 720                 }
 721         }
 722         return nr;
 723 }
 724
 725 void __init smp_detect_cpus(void)
 726 {
 727         unsigned int cpu, mtid, c_cpus, s_cpus;
 728         struct sclp_core_info *info;
 729         u16 address;
 730
 731         /* Get CPU information */
 732         info = memblock_virt_alloc(sizeof(*info), 8);
 733         smp_get_core_info(info, 1);
 734         /* Find boot CPU type */
 735         if (sclp.has_core_type) {
 736                 address = stap();
 737                 for (cpu = 0; cpu < info->combined; cpu++)
 738                         if (info->core[cpu].core_id == address) {
 739                                 /* The boot cpu dictates the cpu type. */
 740                                 boot_core_type = info->core[cpu].type;
 741                                 break;
 742                         }
 743                 if (cpu >= info->combined)
 744                         panic("Could not find boot CPU type");
 745         }
 746
 747         /* Set multi-threading state for the current system */
 748         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 749         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 750         pcpu_set_smt(mtid);
 751
 752         /* Print number of CPUs */
 753         c_cpus = s_cpus = 0;
 754         for (cpu = 0; cpu < info->combined; cpu++) {
 755                 if (sclp.has_core_type &&
 756                     info->core[cpu].type != boot_core_type)
 757                         continue;
 758                 if (cpu < info->configured)
 759                         c_cpus += smp_cpu_mtid + 1;
 760                 else
 761                         s_cpus += smp_cpu_mtid + 1;
 762         }
 763         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 764
 765         /* Add CPUs present at boot */
 766         get_online_cpus();
 767         __smp_rescan_cpus(info, 0);
 768         put_online_cpus();
 769         memblock_free_early((unsigned long)info, sizeof(*info));
 770 }
 771
 772 /*
 773  *      Activate a secondary processor.
 774  */
 775 static void smp_start_secondary(void *cpuvoid)
 776 {
 777         S390_lowcore.last_update_clock = get_tod_clock();
 778         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 779         S390_lowcore.restart_fn = (unsigned long) do_restart;
 780         S390_lowcore.restart_data = 0;
 781         S390_lowcore.restart_source = -1UL;
 782         restore_access_regs(S390_lowcore.access_regs_save_area);
 783         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 784         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 785         cpu_init();
 786         preempt_disable();
 787         init_cpu_timer();
 788         vtime_init();
 789         pfault_init();
 790         notify_cpu_starting(smp_processor_id());
 791         set_cpu_online(smp_processor_id(), true);
 792         inc_irq_stat(CPU_RST);
 793         local_irq_enable();
 794         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 795 }
 796
 797 /* Upping and downing of CPUs */
 798 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 799 {
 800         struct pcpu *pcpu;
 801         int base, i, rc;
 802
 803         pcpu = pcpu_devices + cpu;
 804         if (pcpu->state != CPU_STATE_CONFIGURED)
 805                 return -EIO;
 806         base = smp_get_base_cpu(cpu);
 807         for (i = 0; i <= smp_cpu_mtid; i++) {
 808                 if (base + i < nr_cpu_ids)
 809                         if (cpu_online(base + i))
 810                                 break;
 811         }
 812         /*
 813          * If this is the first CPU of the core to get online
 814          * do an initial CPU reset.
 815          */
 816         if (i > smp_cpu_mtid &&
 817             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 818             SIGP_CC_ORDER_CODE_ACCEPTED)
 819                 return -EIO;
 820
 821         rc = pcpu_alloc_lowcore(pcpu, cpu);
 822         if (rc)
 823                 return rc;
 824         pcpu_prepare_secondary(pcpu, cpu);
 825         pcpu_attach_task(pcpu, tidle);
 826         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 827         /* Wait until cpu puts itself in the online & active maps */
 828         while (!cpu_online(cpu))
 829                 cpu_relax();
 830         return 0;
 831 }
 832
 833 static unsigned int setup_possible_cpus __initdata;
 834
 835 static int __init _setup_possible_cpus(char *s)
 836 {
 837         get_option(&s, &setup_possible_cpus);
 838         return 0;
 839 }
 840 early_param("possible_cpus", _setup_possible_cpus);
 841
 842 #ifdef CONFIG_HOTPLUG_CPU
 843
 844 int __cpu_disable(void)
 845 {
 846         unsigned long cregs[16];
 847
 848         /* Handle possible pending IPIs */
 849         smp_handle_ext_call();
 850         set_cpu_online(smp_processor_id(), false);
 851         /* Disable pseudo page faults on this cpu. */
 852         pfault_fini();
 853         /* Disable interrupt sources via control register. */
 854         __ctl_store(cregs, 0, 15);
 855         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 856         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 857         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 858         __ctl_load(cregs, 0, 15);
 859         clear_cpu_flag(CIF_NOHZ_DELAY);
 860         return 0;
 861 }
 862
 863 void __cpu_die(unsigned int cpu)
 864 {
 865         struct pcpu *pcpu;
 866
 867         /* Wait until target cpu is down */
 868         pcpu = pcpu_devices + cpu;
 869         while (!pcpu_stopped(pcpu))
 870                 cpu_relax();
 871         pcpu_free_lowcore(pcpu);
 872         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 873         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 874 }
 875
 876 void __noreturn cpu_die(void)
 877 {
 878         idle_task_exit();
 879         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 880         for (;;) ;
 881 }
 882
 883 #endif /* CONFIG_HOTPLUG_CPU */
 884
 885 void __init smp_fill_possible_mask(void)
 886 {
 887         unsigned int possible, sclp_max, cpu;
 888
 889         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 890         sclp_max = min(smp_max_threads, sclp_max);
 891         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 892         possible = setup_possible_cpus ?: nr_cpu_ids;
 893         possible = min(possible, sclp_max);
 894         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 895                 set_cpu_possible(cpu, true);
 896 }
 897
 898 void __init smp_prepare_cpus(unsigned int max_cpus)
 899 {
 900         /* request the 0x1201 emergency signal external interrupt */
 901         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 902                 panic("Couldn't request external interrupt 0x1201");
 903         /* request the 0x1202 external call external interrupt */
 904         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 905                 panic("Couldn't request external interrupt 0x1202");
 906 }
 907
 908 void __init smp_prepare_boot_cpu(void)
 909 {
 910         struct pcpu *pcpu = pcpu_devices;
 911
 912         WARN_ON(!cpu_present(0) || !cpu_online(0));
 913         pcpu->state = CPU_STATE_CONFIGURED;
 914         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 915         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 916         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 917 }
 918
 919 void __init smp_cpus_done(unsigned int max_cpus)
 920 {
 921 }
 922
 923 void __init smp_setup_processor_id(void)
 924 {
 925         pcpu_devices[0].address = stap();
 926         S390_lowcore.cpu_nr = 0;
 927         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 928 }
 929
 930 /*
 931  * the frequency of the profiling timer can be changed
 932  * by writing a multiplier value into /proc/profile.
 933  *
 934  * usually you want to run this on all CPUs ;)
 935  */
 936 int setup_profiling_timer(unsigned int multiplier)
 937 {
 938         return 0;
 939 }
 940
 941 #ifdef CONFIG_HOTPLUG_CPU
 942 static ssize_t cpu_configure_show(struct device *dev,
 943                                   struct device_attribute *attr, char *buf)
 944 {
 945         ssize_t count;
 946
 947         mutex_lock(&smp_cpu_state_mutex);
 948         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 949         mutex_unlock(&smp_cpu_state_mutex);
 950         return count;
 951 }
 952
 953 static ssize_t cpu_configure_store(struct device *dev,
 954                                    struct device_attribute *attr,
 955                                    const char *buf, size_t count)
 956 {
 957         struct pcpu *pcpu;
 958         int cpu, val, rc, i;
 959         char delim;
 960
 961         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 962                 return -EINVAL;
 963         if (val != 0 && val != 1)
 964                 return -EINVAL;
 965         get_online_cpus();
 966         mutex_lock(&smp_cpu_state_mutex);
 967         rc = -EBUSY;
 968         /* disallow configuration changes of online cpus and cpu 0 */
 969         cpu = dev->id;
 970         cpu = smp_get_base_cpu(cpu);
 971         if (cpu == 0)
 972                 goto out;
 973         for (i = 0; i <= smp_cpu_mtid; i++)
 974                 if (cpu_online(cpu + i))
 975                         goto out;
 976         pcpu = pcpu_devices + cpu;
 977         rc = 0;
 978         switch (val) {
 979         case 0:
 980                 if (pcpu->state != CPU_STATE_CONFIGURED)
 981                         break;
 982                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
 983                 if (rc)
 984                         break;
 985                 for (i = 0; i <= smp_cpu_mtid; i++) {
 986                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
 987                                 continue;
 988                         pcpu[i].state = CPU_STATE_STANDBY;
 989                         smp_cpu_set_polarization(cpu + i,
 990                                                  POLARIZATION_UNKNOWN);
 991                 }
 992                 topology_expect_change();
 993                 break;
 994         case 1:
 995                 if (pcpu->state != CPU_STATE_STANDBY)
 996                         break;
 997                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
 998                 if (rc)
 999                         break;
1000                 for (i = 0; i <= smp_cpu_mtid; i++) {
1001                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1002                                 continue;
1003                         pcpu[i].state = CPU_STATE_CONFIGURED;
1004                         smp_cpu_set_polarization(cpu + i,
1005                                                  POLARIZATION_UNKNOWN);
1006                 }
1007                 topology_expect_change();
1008                 break;
1009         default:
1010                 break;
1011         }
1012 out:
1013         mutex_unlock(&smp_cpu_state_mutex);
1014         put_online_cpus();
1015         return rc ? rc : count;
1016 }
1017 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1018 #endif /* CONFIG_HOTPLUG_CPU */
1019
1020 static ssize_t show_cpu_address(struct device *dev,
1021                                 struct device_attribute *attr, char *buf)
1022 {
1023         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1024 }
1025 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1026
1027 static struct attribute *cpu_common_attrs[] = {
1028 #ifdef CONFIG_HOTPLUG_CPU
1029         &dev_attr_configure.attr,
1030 #endif
1031         &dev_attr_address.attr,
1032         NULL,
1033 };
1034
1035 static struct attribute_group cpu_common_attr_group = {
1036         .attrs = cpu_common_attrs,
1037 };
1038
1039 static struct attribute *cpu_online_attrs[] = {
1040         &dev_attr_idle_count.attr,
1041         &dev_attr_idle_time_us.attr,
1042         NULL,
1043 };
1044
1045 static struct attribute_group cpu_online_attr_group = {
1046         .attrs = cpu_online_attrs,
1047 };
1048
1049 static int smp_cpu_online(unsigned int cpu)
1050 {
1051         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1052
1053         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1054 }
1055 static int smp_cpu_pre_down(unsigned int cpu)
1056 {
1057         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1058
1059         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1060         return 0;
1061 }
1062
1063 static int smp_add_present_cpu(int cpu)
1064 {
1065         struct device *s;
1066         struct cpu *c;
1067         int rc;
1068
1069         c = kzalloc(sizeof(*c), GFP_KERNEL);
1070         if (!c)
1071                 return -ENOMEM;
1072         per_cpu(cpu_device, cpu) = c;
1073         s = &c->dev;
1074         c->hotpluggable = 1;
1075         rc = register_cpu(c, cpu);
1076         if (rc)
1077                 goto out;
1078         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1079         if (rc)
1080                 goto out_cpu;
1081         rc = topology_cpu_init(c);
1082         if (rc)
1083                 goto out_topology;
1084         return 0;
1085
1086 out_topology:
1087         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1088 out_cpu:
1089 #ifdef CONFIG_HOTPLUG_CPU
1090         unregister_cpu(c);
1091 #endif
1092 out:
1093         return rc;
1094 }
1095
1096 #ifdef CONFIG_HOTPLUG_CPU
1097
1098 int __ref smp_rescan_cpus(void)
1099 {
1100         struct sclp_core_info *info;
1101         int nr;
1102
1103         info = kzalloc(sizeof(*info), GFP_KERNEL);
1104         if (!info)
1105                 return -ENOMEM;
1106         smp_get_core_info(info, 0);
1107         get_online_cpus();
1108         mutex_lock(&smp_cpu_state_mutex);
1109         nr = __smp_rescan_cpus(info, 1);
1110         mutex_unlock(&smp_cpu_state_mutex);
1111         put_online_cpus();
1112         kfree(info);
1113         if (nr)
1114                 topology_schedule_update();
1115         return 0;
1116 }
1117
1118 static ssize_t __ref rescan_store(struct device *dev,
1119                                   struct device_attribute *attr,
1120                                   const char *buf,
1121                                   size_t count)
1122 {
1123         int rc;
1124
1125         rc = smp_rescan_cpus();
1126         return rc ? rc : count;
1127 }
1128 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1129 #endif /* CONFIG_HOTPLUG_CPU */
1130
1131 static int __init s390_smp_init(void)
1132 {
1133         int cpu, rc = 0;
1134
1135 #ifdef CONFIG_HOTPLUG_CPU
1136         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1137         if (rc)
1138                 return rc;
1139 #endif
1140         for_each_present_cpu(cpu) {
1141                 rc = smp_add_present_cpu(cpu);
1142                 if (rc)
1143                         goto out;
1144         }
1145
1146         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1147                                smp_cpu_online, smp_cpu_pre_down);
1148 out:
1149         return rc;
1150 }
1151 subsys_initcall(s390_smp_init);