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/kmemleak.h>
  30 #include <linux/delay.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/irqflags.h>
  33 #include <linux/cpu.h>
  34 #include <linux/slab.h>
  35 #include <linux/sched/hotplug.h>
  36 #include <linux/sched/task_stack.h>
  37 #include <linux/crash_dump.h>
  38 #include <linux/memblock.h>
  39 #include <asm/asm-offsets.h>
  40 #include <asm/diag.h>
  41 #include <asm/switch_to.h>
  42 #include <asm/facility.h>
  43 #include <asm/ipl.h>
  44 #include <asm/setup.h>
  45 #include <asm/irq.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/vtimer.h>
  48 #include <asm/lowcore.h>
  49 #include <asm/sclp.h>
  50 #include <asm/vdso.h>
  51 #include <asm/debug.h>
  52 #include <asm/os_info.h>
  53 #include <asm/sigp.h>
  54 #include <asm/idle.h>
  55 #include <asm/nmi.h>
  56 #include "entry.h"
  57
  58 enum {
  59         ec_schedule = 0,
  60         ec_call_function_single,
  61         ec_stop_cpu,
  62 };
  63
  64 enum {
  65         CPU_STATE_STANDBY,
  66         CPU_STATE_CONFIGURED,
  67 };
  68
  69 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  70
  71 struct pcpu {
  72         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  73         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  74         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  75         signed char state;              /* physical cpu state */
  76         signed char polarization;       /* physical polarization */
  77         u16 address;                    /* physical cpu address */
  78 };
  79
  80 static u8 boot_core_type;
  81 static struct pcpu pcpu_devices[NR_CPUS];
  82
  83 static struct kmem_cache *pcpu_mcesa_cache;
  84
  85 unsigned int smp_cpu_mt_shift;
  86 EXPORT_SYMBOL(smp_cpu_mt_shift);
  87
  88 unsigned int smp_cpu_mtid;
  89 EXPORT_SYMBOL(smp_cpu_mtid);
  90
  91 #ifdef CONFIG_CRASH_DUMP
  92 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  93 #endif
  94
  95 static unsigned int smp_max_threads __initdata = -1U;
  96
  97 static int __init early_nosmt(char *s)
  98 {
  99         smp_max_threads = 1;
 100         return 0;
 101 }
 102 early_param("nosmt", early_nosmt);
 103
 104 static int __init early_smt(char *s)
 105 {
 106         get_option(&s, &smp_max_threads);
 107         return 0;
 108 }
 109 early_param("smt", early_smt);
 110
 111 /*
 112  * The smp_cpu_state_mutex must be held when changing the state or polarization
 113  * member of a pcpu data structure within the pcpu_devices arreay.
 114  */
 115 DEFINE_MUTEX(smp_cpu_state_mutex);
 116
 117 /*
 118  * Signal processor helper functions.
 119  */
 120 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 121 {
 122         int cc;
 123
 124         while (1) {
 125                 cc = __pcpu_sigp(addr, order, parm, NULL);
 126                 if (cc != SIGP_CC_BUSY)
 127                         return cc;
 128                 cpu_relax();
 129         }
 130 }
 131
 132 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 133 {
 134         int cc, retry;
 135
 136         for (retry = 0; ; retry++) {
 137                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 138                 if (cc != SIGP_CC_BUSY)
 139                         break;
 140                 if (retry >= 3)
 141                         udelay(10);
 142         }
 143         return cc;
 144 }
 145
 146 static inline int pcpu_stopped(struct pcpu *pcpu)
 147 {
 148         u32 uninitialized_var(status);
 149
 150         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 151                         0, &status) != SIGP_CC_STATUS_STORED)
 152                 return 0;
 153         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 154 }
 155
 156 static inline int pcpu_running(struct pcpu *pcpu)
 157 {
 158         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 159                         0, NULL) != SIGP_CC_STATUS_STORED)
 160                 return 1;
 161         /* Status stored condition code is equivalent to cpu not running. */
 162         return 0;
 163 }
 164
 165 /*
 166  * Find struct pcpu by cpu address.
 167  */
 168 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 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         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 183                 return;
 184         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 185         pcpu->ec_clk = get_tod_clock_fast();
 186         pcpu_sigp_retry(pcpu, order, 0);
 187 }
 188
 189 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 190 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 191
 192 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 193 {
 194         unsigned long async_stack, panic_stack;
 195         unsigned long mcesa_origin, mcesa_bits;
 196         struct lowcore *lc;
 197
 198         mcesa_origin = mcesa_bits = 0;
 199         if (pcpu != &pcpu_devices[0]) {
 200                 pcpu->lowcore = (struct lowcore *)
 201                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 202                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 203                 panic_stack = __get_free_page(GFP_KERNEL);
 204                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 205                         goto out;
 206                 if (MACHINE_HAS_VX || MACHINE_HAS_GS) {
 207                         mcesa_origin = (unsigned long)
 208                                 kmem_cache_alloc(pcpu_mcesa_cache, GFP_KERNEL);
 209                         if (!mcesa_origin)
 210                                 goto out;
 211                         /* The pointer is stored with mcesa_bits ORed in */
 212                         kmemleak_not_leak((void *) mcesa_origin);
 213                         mcesa_bits = MACHINE_HAS_GS ? 11 : 0;
 214                 }
 215         } else {
 216                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 217                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 218                 mcesa_origin = pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK;
 219                 mcesa_bits = pcpu->lowcore->mcesad & MCESA_LC_MASK;
 220         }
 221         lc = pcpu->lowcore;
 222         memcpy(lc, &S390_lowcore, 512);
 223         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 224         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 225         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 226         lc->mcesad = mcesa_origin | mcesa_bits;
 227         lc->cpu_nr = cpu;
 228         lc->spinlock_lockval = arch_spin_lockval(cpu);
 229         if (vdso_alloc_per_cpu(lc))
 230                 goto out;
 231         lowcore_ptr[cpu] = lc;
 232         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 233         return 0;
 234 out:
 235         if (pcpu != &pcpu_devices[0]) {
 236                 if (mcesa_origin)
 237                         kmem_cache_free(pcpu_mcesa_cache,
 238                                         (void *) mcesa_origin);
 239                 free_page(panic_stack);
 240                 free_pages(async_stack, ASYNC_ORDER);
 241                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 242         }
 243         return -ENOMEM;
 244 }
 245
 246 #ifdef CONFIG_HOTPLUG_CPU
 247
 248 static void pcpu_free_lowcore(struct pcpu *pcpu)
 249 {
 250         unsigned long mcesa_origin;
 251
 252         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 253         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 254         vdso_free_per_cpu(pcpu->lowcore);
 255         if (pcpu == &pcpu_devices[0])
 256                 return;
 257         if (MACHINE_HAS_VX || MACHINE_HAS_GS) {
 258                 mcesa_origin = pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK;
 259                 kmem_cache_free(pcpu_mcesa_cache, (void *) mcesa_origin);
 260         }
 261         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 262         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 263         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 264 }
 265
 266 #endif /* CONFIG_HOTPLUG_CPU */
 267
 268 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 269 {
 270         struct lowcore *lc = pcpu->lowcore;
 271
 272         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 273         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 274         lc->cpu_nr = cpu;
 275         lc->spinlock_lockval = arch_spin_lockval(cpu);
 276         lc->percpu_offset = __per_cpu_offset[cpu];
 277         lc->kernel_asce = S390_lowcore.kernel_asce;
 278         lc->machine_flags = S390_lowcore.machine_flags;
 279         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 280         __ctl_store(lc->cregs_save_area, 0, 15);
 281         save_access_regs((unsigned int *) lc->access_regs_save_area);
 282         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 283                MAX_FACILITY_BIT/8);
 284 }
 285
 286 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 287 {
 288         struct lowcore *lc = pcpu->lowcore;
 289
 290         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 291                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 292         lc->current_task = (unsigned long) tsk;
 293         lc->lpp = LPP_MAGIC;
 294         lc->current_pid = tsk->pid;
 295         lc->user_timer = tsk->thread.user_timer;
 296         lc->system_timer = tsk->thread.system_timer;
 297         lc->steal_timer = 0;
 298 }
 299
 300 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 301 {
 302         struct lowcore *lc = pcpu->lowcore;
 303
 304         lc->restart_stack = lc->kernel_stack;
 305         lc->restart_fn = (unsigned long) func;
 306         lc->restart_data = (unsigned long) data;
 307         lc->restart_source = -1UL;
 308         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 309 }
 310
 311 /*
 312  * Call function via PSW restart on pcpu and stop the current cpu.
 313  */
 314 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 315                           void *data, unsigned long stack)
 316 {
 317         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 318         unsigned long source_cpu = stap();
 319
 320         __load_psw_mask(PSW_KERNEL_BITS);
 321         if (pcpu->address == source_cpu)
 322                 func(data);     /* should not return */
 323         /* Stop target cpu (if func returns this stops the current cpu). */
 324         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 325         /* Restart func on the target cpu and stop the current cpu. */
 326         mem_assign_absolute(lc->restart_stack, stack);
 327         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 328         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 329         mem_assign_absolute(lc->restart_source, source_cpu);
 330         asm volatile(
 331                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 332                 "       brc     2,0b    # busy, try again\n"
 333                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 334                 "       brc     2,1b    # busy, try again\n"
 335                 : : "d" (pcpu->address), "d" (source_cpu),
 336                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 337                 : "0", "1", "cc");
 338         for (;;) ;
 339 }
 340
 341 /*
 342  * Enable additional logical cpus for multi-threading.
 343  */
 344 static int pcpu_set_smt(unsigned int mtid)
 345 {
 346         int cc;
 347
 348         if (smp_cpu_mtid == mtid)
 349                 return 0;
 350         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 351         if (cc == 0) {
 352                 smp_cpu_mtid = mtid;
 353                 smp_cpu_mt_shift = 0;
 354                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 355                         smp_cpu_mt_shift++;
 356                 pcpu_devices[0].address = stap();
 357         }
 358         return cc;
 359 }
 360
 361 /*
 362  * Call function on an online CPU.
 363  */
 364 void smp_call_online_cpu(void (*func)(void *), void *data)
 365 {
 366         struct pcpu *pcpu;
 367
 368         /* Use the current cpu if it is online. */
 369         pcpu = pcpu_find_address(cpu_online_mask, stap());
 370         if (!pcpu)
 371                 /* Use the first online cpu. */
 372                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 373         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 374 }
 375
 376 /*
 377  * Call function on the ipl CPU.
 378  */
 379 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 380 {
 381         pcpu_delegate(&pcpu_devices[0], func, data,
 382                       pcpu_devices->lowcore->panic_stack -
 383                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 384 }
 385
 386 int smp_find_processor_id(u16 address)
 387 {
 388         int cpu;
 389
 390         for_each_present_cpu(cpu)
 391                 if (pcpu_devices[cpu].address == address)
 392                         return cpu;
 393         return -1;
 394 }
 395
 396 bool arch_vcpu_is_preempted(int cpu)
 397 {
 398         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 399                 return false;
 400         if (pcpu_running(pcpu_devices + cpu))
 401                 return false;
 402         return true;
 403 }
 404 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 405
 406 void smp_yield_cpu(int cpu)
 407 {
 408         if (MACHINE_HAS_DIAG9C) {
 409                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 410                 asm volatile("diag %0,0,0x9c"
 411                              : : "d" (pcpu_devices[cpu].address));
 412         } else if (MACHINE_HAS_DIAG44) {
 413                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 414                 asm volatile("diag 0,0,0x44");
 415         }
 416 }
 417
 418 /*
 419  * Send cpus emergency shutdown signal. This gives the cpus the
 420  * opportunity to complete outstanding interrupts.
 421  */
 422 static void smp_emergency_stop(cpumask_t *cpumask)
 423 {
 424         u64 end;
 425         int cpu;
 426
 427         end = get_tod_clock() + (1000000UL << 12);
 428         for_each_cpu(cpu, cpumask) {
 429                 struct pcpu *pcpu = pcpu_devices + cpu;
 430                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 431                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 432                                    0, NULL) == SIGP_CC_BUSY &&
 433                        get_tod_clock() < end)
 434                         cpu_relax();
 435         }
 436         while (get_tod_clock() < end) {
 437                 for_each_cpu(cpu, cpumask)
 438                         if (pcpu_stopped(pcpu_devices + cpu))
 439                                 cpumask_clear_cpu(cpu, cpumask);
 440                 if (cpumask_empty(cpumask))
 441                         break;
 442                 cpu_relax();
 443         }
 444 }
 445
 446 /*
 447  * Stop all cpus but the current one.
 448  */
 449 void smp_send_stop(void)
 450 {
 451         cpumask_t cpumask;
 452         int cpu;
 453
 454         /* Disable all interrupts/machine checks */
 455         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 456         trace_hardirqs_off();
 457
 458         debug_set_critical();
 459         cpumask_copy(&cpumask, cpu_online_mask);
 460         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 461
 462         if (oops_in_progress)
 463                 smp_emergency_stop(&cpumask);
 464
 465         /* stop all processors */
 466         for_each_cpu(cpu, &cpumask) {
 467                 struct pcpu *pcpu = pcpu_devices + cpu;
 468                 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 469                 while (!pcpu_stopped(pcpu))
 470                         cpu_relax();
 471         }
 472 }
 473
 474 /*
 475  * This is the main routine where commands issued by other
 476  * cpus are handled.
 477  */
 478 static void smp_handle_ext_call(void)
 479 {
 480         unsigned long bits;
 481
 482         /* handle bit signal external calls */
 483         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 484         if (test_bit(ec_stop_cpu, &bits))
 485                 smp_stop_cpu();
 486         if (test_bit(ec_schedule, &bits))
 487                 scheduler_ipi();
 488         if (test_bit(ec_call_function_single, &bits))
 489                 generic_smp_call_function_single_interrupt();
 490 }
 491
 492 static void do_ext_call_interrupt(struct ext_code ext_code,
 493                                   unsigned int param32, unsigned long param64)
 494 {
 495         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 496         smp_handle_ext_call();
 497 }
 498
 499 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 500 {
 501         int cpu;
 502
 503         for_each_cpu(cpu, mask)
 504                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 505 }
 506
 507 void arch_send_call_function_single_ipi(int cpu)
 508 {
 509         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 510 }
 511
 512 /*
 513  * this function sends a 'reschedule' IPI to another CPU.
 514  * it goes straight through and wastes no time serializing
 515  * anything. Worst case is that we lose a reschedule ...
 516  */
 517 void smp_send_reschedule(int cpu)
 518 {
 519         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 520 }
 521
 522 /*
 523  * parameter area for the set/clear control bit callbacks
 524  */
 525 struct ec_creg_mask_parms {
 526         unsigned long orval;
 527         unsigned long andval;
 528         int cr;
 529 };
 530
 531 /*
 532  * callback for setting/clearing control bits
 533  */
 534 static void smp_ctl_bit_callback(void *info)
 535 {
 536         struct ec_creg_mask_parms *pp = info;
 537         unsigned long cregs[16];
 538
 539         __ctl_store(cregs, 0, 15);
 540         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 541         __ctl_load(cregs, 0, 15);
 542 }
 543
 544 /*
 545  * Set a bit in a control register of all cpus
 546  */
 547 void smp_ctl_set_bit(int cr, int bit)
 548 {
 549         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 550
 551         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 552 }
 553 EXPORT_SYMBOL(smp_ctl_set_bit);
 554
 555 /*
 556  * Clear a bit in a control register of all cpus
 557  */
 558 void smp_ctl_clear_bit(int cr, int bit)
 559 {
 560         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 561
 562         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 563 }
 564 EXPORT_SYMBOL(smp_ctl_clear_bit);
 565
 566 #ifdef CONFIG_CRASH_DUMP
 567
 568 int smp_store_status(int cpu)
 569 {
 570         struct pcpu *pcpu = pcpu_devices + cpu;
 571         unsigned long pa;
 572
 573         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 574         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 575                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 576                 return -EIO;
 577         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
 578                 return 0;
 579         pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
 580         if (MACHINE_HAS_GS)
 581                 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
 582         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 583                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 584                 return -EIO;
 585         return 0;
 586 }
 587
 588 /*
 589  * Collect CPU state of the previous, crashed system.
 590  * There are four cases:
 591  * 1) standard zfcp dump
 592  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 593  *    The state for all CPUs except the boot CPU needs to be collected
 594  *    with sigp stop-and-store-status. The boot CPU state is located in
 595  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 596  *    will copy the boot CPU state from the HSA.
 597  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 598  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 599  *    The state for all CPUs except the boot CPU needs to be collected
 600  *    with sigp stop-and-store-status. The firmware or the boot-loader
 601  *    stored the registers of the boot CPU in the absolute lowcore in the
 602  *    memory of the old system.
 603  * 3) kdump and the old kernel did not store the CPU state,
 604  *    or stand-alone kdump for DASD
 605  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 606  *    The state for all CPUs except the boot CPU needs to be collected
 607  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 608  *    stored the registers of the boot CPU in the memory of the old system.
 609  * 4) kdump and the old kernel stored the CPU state
 610  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 611  *    This case does not exist for s390 anymore, setup_arch explicitly
 612  *    deactivates the elfcorehdr= kernel parameter
 613  */
 614 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 615                                      bool is_boot_cpu, unsigned long page)
 616 {
 617         __vector128 *vxrs = (__vector128 *) page;
 618
 619         if (is_boot_cpu)
 620                 vxrs = boot_cpu_vector_save_area;
 621         else
 622                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 623         save_area_add_vxrs(sa, vxrs);
 624 }
 625
 626 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 627                                      bool is_boot_cpu, unsigned long page)
 628 {
 629         void *regs = (void *) page;
 630
 631         if (is_boot_cpu)
 632                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 633         else
 634                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 635         save_area_add_regs(sa, regs);
 636 }
 637
 638 void __init smp_save_dump_cpus(void)
 639 {
 640         int addr, boot_cpu_addr, max_cpu_addr;
 641         struct save_area *sa;
 642         unsigned long page;
 643         bool is_boot_cpu;
 644
 645         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 646                 /* No previous system present, normal boot. */
 647                 return;
 648         /* Allocate a page as dumping area for the store status sigps */
 649         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 650         /* Set multi-threading state to the previous system. */
 651         pcpu_set_smt(sclp.mtid_prev);
 652         boot_cpu_addr = stap();
 653         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 654         for (addr = 0; addr <= max_cpu_addr; addr++) {
 655                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 656                     SIGP_CC_NOT_OPERATIONAL)
 657                         continue;
 658                 is_boot_cpu = (addr == boot_cpu_addr);
 659                 /* Allocate save area */
 660                 sa = save_area_alloc(is_boot_cpu);
 661                 if (!sa)
 662                         panic("could not allocate memory for save area\n");
 663                 if (MACHINE_HAS_VX)
 664                         /* Get the vector registers */
 665                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 666                 /*
 667                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 668                  * of the boot CPU are stored in the HSA. To retrieve
 669                  * these registers an SCLP request is required which is
 670                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 671                  */
 672                 if (!is_boot_cpu || OLDMEM_BASE)
 673                         /* Get the CPU registers */
 674                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 675         }
 676         memblock_free(page, PAGE_SIZE);
 677         diag308_reset();
 678         pcpu_set_smt(0);
 679 }
 680 #endif /* CONFIG_CRASH_DUMP */
 681
 682 void smp_cpu_set_polarization(int cpu, int val)
 683 {
 684         pcpu_devices[cpu].polarization = val;
 685 }
 686
 687 int smp_cpu_get_polarization(int cpu)
 688 {
 689         return pcpu_devices[cpu].polarization;
 690 }
 691
 692 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 693 {
 694         static int use_sigp_detection;
 695         int address;
 696
 697         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 698                 use_sigp_detection = 1;
 699                 for (address = 0;
 700                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 701                      address += (1U << smp_cpu_mt_shift)) {
 702                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 703                             SIGP_CC_NOT_OPERATIONAL)
 704                                 continue;
 705                         info->core[info->configured].core_id =
 706                                 address >> smp_cpu_mt_shift;
 707                         info->configured++;
 708                 }
 709                 info->combined = info->configured;
 710         }
 711 }
 712
 713 static int smp_add_present_cpu(int cpu);
 714
 715 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 716 {
 717         struct pcpu *pcpu;
 718         cpumask_t avail;
 719         int cpu, nr, i, j;
 720         u16 address;
 721
 722         nr = 0;
 723         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 724         cpu = cpumask_first(&avail);
 725         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 726                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 727                         continue;
 728                 address = info->core[i].core_id << smp_cpu_mt_shift;
 729                 for (j = 0; j <= smp_cpu_mtid; j++) {
 730                         if (pcpu_find_address(cpu_present_mask, address + j))
 731                                 continue;
 732                         pcpu = pcpu_devices + cpu;
 733                         pcpu->address = address + j;
 734                         pcpu->state =
 735                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 736                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 737                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 738                         set_cpu_present(cpu, true);
 739                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 740                                 set_cpu_present(cpu, false);
 741                         else
 742                                 nr++;
 743                         cpu = cpumask_next(cpu, &avail);
 744                         if (cpu >= nr_cpu_ids)
 745                                 break;
 746                 }
 747         }
 748         return nr;
 749 }
 750
 751 void __init smp_detect_cpus(void)
 752 {
 753         unsigned int cpu, mtid, c_cpus, s_cpus;
 754         struct sclp_core_info *info;
 755         u16 address;
 756
 757         /* Get CPU information */
 758         info = memblock_virt_alloc(sizeof(*info), 8);
 759         smp_get_core_info(info, 1);
 760         /* Find boot CPU type */
 761         if (sclp.has_core_type) {
 762                 address = stap();
 763                 for (cpu = 0; cpu < info->combined; cpu++)
 764                         if (info->core[cpu].core_id == address) {
 765                                 /* The boot cpu dictates the cpu type. */
 766                                 boot_core_type = info->core[cpu].type;
 767                                 break;
 768                         }
 769                 if (cpu >= info->combined)
 770                         panic("Could not find boot CPU type");
 771         }
 772
 773         /* Set multi-threading state for the current system */
 774         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 775         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 776         pcpu_set_smt(mtid);
 777
 778         /* Print number of CPUs */
 779         c_cpus = s_cpus = 0;
 780         for (cpu = 0; cpu < info->combined; cpu++) {
 781                 if (sclp.has_core_type &&
 782                     info->core[cpu].type != boot_core_type)
 783                         continue;
 784                 if (cpu < info->configured)
 785                         c_cpus += smp_cpu_mtid + 1;
 786                 else
 787                         s_cpus += smp_cpu_mtid + 1;
 788         }
 789         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 790
 791         /* Add CPUs present at boot */
 792         get_online_cpus();
 793         __smp_rescan_cpus(info, 0);
 794         put_online_cpus();
 795         memblock_free_early((unsigned long)info, sizeof(*info));
 796 }
 797
 798 /*
 799  *      Activate a secondary processor.
 800  */
 801 static void smp_start_secondary(void *cpuvoid)
 802 {
 803         S390_lowcore.last_update_clock = get_tod_clock();
 804         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 805         S390_lowcore.restart_fn = (unsigned long) do_restart;
 806         S390_lowcore.restart_data = 0;
 807         S390_lowcore.restart_source = -1UL;
 808         restore_access_regs(S390_lowcore.access_regs_save_area);
 809         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 810         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 811         cpu_init();
 812         preempt_disable();
 813         init_cpu_timer();
 814         vtime_init();
 815         pfault_init();
 816         notify_cpu_starting(smp_processor_id());
 817         set_cpu_online(smp_processor_id(), true);
 818         inc_irq_stat(CPU_RST);
 819         local_irq_enable();
 820         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 821 }
 822
 823 /* Upping and downing of CPUs */
 824 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 825 {
 826         struct pcpu *pcpu;
 827         int base, i, rc;
 828
 829         pcpu = pcpu_devices + cpu;
 830         if (pcpu->state != CPU_STATE_CONFIGURED)
 831                 return -EIO;
 832         base = smp_get_base_cpu(cpu);
 833         for (i = 0; i <= smp_cpu_mtid; i++) {
 834                 if (base + i < nr_cpu_ids)
 835                         if (cpu_online(base + i))
 836                                 break;
 837         }
 838         /*
 839          * If this is the first CPU of the core to get online
 840          * do an initial CPU reset.
 841          */
 842         if (i > smp_cpu_mtid &&
 843             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 844             SIGP_CC_ORDER_CODE_ACCEPTED)
 845                 return -EIO;
 846
 847         rc = pcpu_alloc_lowcore(pcpu, cpu);
 848         if (rc)
 849                 return rc;
 850         pcpu_prepare_secondary(pcpu, cpu);
 851         pcpu_attach_task(pcpu, tidle);
 852         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 853         /* Wait until cpu puts itself in the online & active maps */
 854         while (!cpu_online(cpu))
 855                 cpu_relax();
 856         return 0;
 857 }
 858
 859 static unsigned int setup_possible_cpus __initdata;
 860
 861 static int __init _setup_possible_cpus(char *s)
 862 {
 863         get_option(&s, &setup_possible_cpus);
 864         return 0;
 865 }
 866 early_param("possible_cpus", _setup_possible_cpus);
 867
 868 #ifdef CONFIG_HOTPLUG_CPU
 869
 870 int __cpu_disable(void)
 871 {
 872         unsigned long cregs[16];
 873
 874         /* Handle possible pending IPIs */
 875         smp_handle_ext_call();
 876         set_cpu_online(smp_processor_id(), false);
 877         /* Disable pseudo page faults on this cpu. */
 878         pfault_fini();
 879         /* Disable interrupt sources via control register. */
 880         __ctl_store(cregs, 0, 15);
 881         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 882         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 883         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 884         __ctl_load(cregs, 0, 15);
 885         clear_cpu_flag(CIF_NOHZ_DELAY);
 886         return 0;
 887 }
 888
 889 void __cpu_die(unsigned int cpu)
 890 {
 891         struct pcpu *pcpu;
 892
 893         /* Wait until target cpu is down */
 894         pcpu = pcpu_devices + cpu;
 895         while (!pcpu_stopped(pcpu))
 896                 cpu_relax();
 897         pcpu_free_lowcore(pcpu);
 898         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 899         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 900 }
 901
 902 void __noreturn cpu_die(void)
 903 {
 904         idle_task_exit();
 905         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 906         for (;;) ;
 907 }
 908
 909 #endif /* CONFIG_HOTPLUG_CPU */
 910
 911 void __init smp_fill_possible_mask(void)
 912 {
 913         unsigned int possible, sclp_max, cpu;
 914
 915         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 916         sclp_max = min(smp_max_threads, sclp_max);
 917         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 918         possible = setup_possible_cpus ?: nr_cpu_ids;
 919         possible = min(possible, sclp_max);
 920         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 921                 set_cpu_possible(cpu, true);
 922 }
 923
 924 void __init smp_prepare_cpus(unsigned int max_cpus)
 925 {
 926         unsigned long size;
 927
 928         /* request the 0x1201 emergency signal external interrupt */
 929         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 930                 panic("Couldn't request external interrupt 0x1201");
 931         /* request the 0x1202 external call external interrupt */
 932         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 933                 panic("Couldn't request external interrupt 0x1202");
 934         /* create slab cache for the machine-check-extended-save-areas */
 935         if (MACHINE_HAS_VX || MACHINE_HAS_GS) {
 936                 size = 1UL << (MACHINE_HAS_GS ? 11 : 10);
 937                 pcpu_mcesa_cache = kmem_cache_create("nmi_save_areas",
 938                                                      size, size, 0, NULL);
 939                 if (!pcpu_mcesa_cache)
 940                         panic("Couldn't create nmi save area cache");
 941         }
 942 }
 943
 944 void __init smp_prepare_boot_cpu(void)
 945 {
 946         struct pcpu *pcpu = pcpu_devices;
 947
 948         WARN_ON(!cpu_present(0) || !cpu_online(0));
 949         pcpu->state = CPU_STATE_CONFIGURED;
 950         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 951         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 952         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 953 }
 954
 955 void __init smp_cpus_done(unsigned int max_cpus)
 956 {
 957 }
 958
 959 void __init smp_setup_processor_id(void)
 960 {
 961         pcpu_devices[0].address = stap();
 962         S390_lowcore.cpu_nr = 0;
 963         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 964 }
 965
 966 /*
 967  * the frequency of the profiling timer can be changed
 968  * by writing a multiplier value into /proc/profile.
 969  *
 970  * usually you want to run this on all CPUs ;)
 971  */
 972 int setup_profiling_timer(unsigned int multiplier)
 973 {
 974         return 0;
 975 }
 976
 977 #ifdef CONFIG_HOTPLUG_CPU
 978 static ssize_t cpu_configure_show(struct device *dev,
 979                                   struct device_attribute *attr, char *buf)
 980 {
 981         ssize_t count;
 982
 983         mutex_lock(&smp_cpu_state_mutex);
 984         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 985         mutex_unlock(&smp_cpu_state_mutex);
 986         return count;
 987 }
 988
 989 static ssize_t cpu_configure_store(struct device *dev,
 990                                    struct device_attribute *attr,
 991                                    const char *buf, size_t count)
 992 {
 993         struct pcpu *pcpu;
 994         int cpu, val, rc, i;
 995         char delim;
 996
 997         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 998                 return -EINVAL;
 999         if (val != 0 && val != 1)
1000                 return -EINVAL;
1001         get_online_cpus();
1002         mutex_lock(&smp_cpu_state_mutex);
1003         rc = -EBUSY;
1004         /* disallow configuration changes of online cpus and cpu 0 */
1005         cpu = dev->id;
1006         cpu = smp_get_base_cpu(cpu);
1007         if (cpu == 0)
1008                 goto out;
1009         for (i = 0; i <= smp_cpu_mtid; i++)
1010                 if (cpu_online(cpu + i))
1011                         goto out;
1012         pcpu = pcpu_devices + cpu;
1013         rc = 0;
1014         switch (val) {
1015         case 0:
1016                 if (pcpu->state != CPU_STATE_CONFIGURED)
1017                         break;
1018                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1019                 if (rc)
1020                         break;
1021                 for (i = 0; i <= smp_cpu_mtid; i++) {
1022                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1023                                 continue;
1024                         pcpu[i].state = CPU_STATE_STANDBY;
1025                         smp_cpu_set_polarization(cpu + i,
1026                                                  POLARIZATION_UNKNOWN);
1027                 }
1028                 topology_expect_change();
1029                 break;
1030         case 1:
1031                 if (pcpu->state != CPU_STATE_STANDBY)
1032                         break;
1033                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1034                 if (rc)
1035                         break;
1036                 for (i = 0; i <= smp_cpu_mtid; i++) {
1037                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1038                                 continue;
1039                         pcpu[i].state = CPU_STATE_CONFIGURED;
1040                         smp_cpu_set_polarization(cpu + i,
1041                                                  POLARIZATION_UNKNOWN);
1042                 }
1043                 topology_expect_change();
1044                 break;
1045         default:
1046                 break;
1047         }
1048 out:
1049         mutex_unlock(&smp_cpu_state_mutex);
1050         put_online_cpus();
1051         return rc ? rc : count;
1052 }
1053 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1054 #endif /* CONFIG_HOTPLUG_CPU */
1055
1056 static ssize_t show_cpu_address(struct device *dev,
1057                                 struct device_attribute *attr, char *buf)
1058 {
1059         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1060 }
1061 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1062
1063 static struct attribute *cpu_common_attrs[] = {
1064 #ifdef CONFIG_HOTPLUG_CPU
1065         &dev_attr_configure.attr,
1066 #endif
1067         &dev_attr_address.attr,
1068         NULL,
1069 };
1070
1071 static struct attribute_group cpu_common_attr_group = {
1072         .attrs = cpu_common_attrs,
1073 };
1074
1075 static struct attribute *cpu_online_attrs[] = {
1076         &dev_attr_idle_count.attr,
1077         &dev_attr_idle_time_us.attr,
1078         NULL,
1079 };
1080
1081 static struct attribute_group cpu_online_attr_group = {
1082         .attrs = cpu_online_attrs,
1083 };
1084
1085 static int smp_cpu_online(unsigned int cpu)
1086 {
1087         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1088
1089         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1090 }
1091 static int smp_cpu_pre_down(unsigned int cpu)
1092 {
1093         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1094
1095         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1096         return 0;
1097 }
1098
1099 static int smp_add_present_cpu(int cpu)
1100 {
1101         struct device *s;
1102         struct cpu *c;
1103         int rc;
1104
1105         c = kzalloc(sizeof(*c), GFP_KERNEL);
1106         if (!c)
1107                 return -ENOMEM;
1108         per_cpu(cpu_device, cpu) = c;
1109         s = &c->dev;
1110         c->hotpluggable = 1;
1111         rc = register_cpu(c, cpu);
1112         if (rc)
1113                 goto out;
1114         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1115         if (rc)
1116                 goto out_cpu;
1117         rc = topology_cpu_init(c);
1118         if (rc)
1119                 goto out_topology;
1120         return 0;
1121
1122 out_topology:
1123         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1124 out_cpu:
1125 #ifdef CONFIG_HOTPLUG_CPU
1126         unregister_cpu(c);
1127 #endif
1128 out:
1129         return rc;
1130 }
1131
1132 #ifdef CONFIG_HOTPLUG_CPU
1133
1134 int __ref smp_rescan_cpus(void)
1135 {
1136         struct sclp_core_info *info;
1137         int nr;
1138
1139         info = kzalloc(sizeof(*info), GFP_KERNEL);
1140         if (!info)
1141                 return -ENOMEM;
1142         smp_get_core_info(info, 0);
1143         get_online_cpus();
1144         mutex_lock(&smp_cpu_state_mutex);
1145         nr = __smp_rescan_cpus(info, 1);
1146         mutex_unlock(&smp_cpu_state_mutex);
1147         put_online_cpus();
1148         kfree(info);
1149         if (nr)
1150                 topology_schedule_update();
1151         return 0;
1152 }
1153
1154 static ssize_t __ref rescan_store(struct device *dev,
1155                                   struct device_attribute *attr,
1156                                   const char *buf,
1157                                   size_t count)
1158 {
1159         int rc;
1160
1161         rc = smp_rescan_cpus();
1162         return rc ? rc : count;
1163 }
1164 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1165 #endif /* CONFIG_HOTPLUG_CPU */
1166
1167 static int __init s390_smp_init(void)
1168 {
1169         int cpu, rc = 0;
1170
1171 #ifdef CONFIG_HOTPLUG_CPU
1172         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1173         if (rc)
1174                 return rc;
1175 #endif
1176         for_each_present_cpu(cpu) {
1177                 rc = smp_add_present_cpu(cpu);
1178                 if (rc)
1179                         goto out;
1180         }
1181
1182         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1183                                smp_cpu_online, smp_cpu_pre_down);
1184         rc = rc <= 0 ? rc : 0;
1185 out:
1186         return rc;
1187 }
1188 subsys_initcall(s390_smp_init);