arch/s390/kernel/smp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  SMP related functions
   4  *
   5  *    Copyright IBM Corp. 1999, 2012
   6  *    Author(s): Denis Joseph Barrow,
   7  *               Martin Schwidefsky <schwidefsky@de.ibm.com>,
   8  *               Heiko Carstens <heiko.carstens@de.ibm.com>,
   9  *
  10  *  based on other smp stuff by
  11  *    (c) 1995 Alan Cox, CymruNET Ltd  <alan@cymru.net>
  12  *    (c) 1998 Ingo Molnar
  13  *
  14  * The code outside of smp.c uses logical cpu numbers, only smp.c does
  15  * the translation of logical to physical cpu ids. All new code that
  16  * operates on physical cpu numbers needs to go into smp.c.
  17  */
  18
  19 #define KMSG_COMPONENT "cpu"
  20 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  21
  22 #include <linux/workqueue.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/export.h>
  25 #include <linux/init.h>
  26 #include <linux/mm.h>
  27 #include <linux/err.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/kernel_stat.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 <linux/kprobes.h>
  40 #include <asm/asm-offsets.h>
  41 #include <asm/diag.h>
  42 #include <asm/switch_to.h>
  43 #include <asm/facility.h>
  44 #include <asm/ipl.h>
  45 #include <asm/setup.h>
  46 #include <asm/irq.h>
  47 #include <asm/tlbflush.h>
  48 #include <asm/vtimer.h>
  49 #include <asm/lowcore.h>
  50 #include <asm/sclp.h>
  51 #include <asm/vdso.h>
  52 #include <asm/debug.h>
  53 #include <asm/os_info.h>
  54 #include <asm/sigp.h>
  55 #include <asm/idle.h>
  56 #include <asm/nmi.h>
  57 #include <asm/topology.h>
  58 #include "entry.h"
  59
  60 enum {
  61         ec_schedule = 0,
  62         ec_call_function_single,
  63         ec_stop_cpu,
  64 };
  65
  66 enum {
  67         CPU_STATE_STANDBY,
  68         CPU_STATE_CONFIGURED,
  69 };
  70
  71 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  72
  73 struct pcpu {
  74         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  75         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  76         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  77         signed char state;              /* physical cpu state */
  78         signed char polarization;       /* physical polarization */
  79         u16 address;                    /* physical cpu address */
  80 };
  81
  82 static u8 boot_core_type;
  83 static struct pcpu pcpu_devices[NR_CPUS];
  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         struct lowcore *lc;
 196
 197         if (pcpu != &pcpu_devices[0]) {
 198                 pcpu->lowcore = (struct lowcore *)
 199                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 200                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 201                 panic_stack = __get_free_page(GFP_KERNEL);
 202                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 203                         goto out;
 204         } else {
 205                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 206                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 207         }
 208         lc = pcpu->lowcore;
 209         memcpy(lc, &S390_lowcore, 512);
 210         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 211         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 212         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 213         lc->cpu_nr = cpu;
 214         lc->spinlock_lockval = arch_spin_lockval(cpu);
 215         lc->spinlock_index = 0;
 216         lc->br_r1_trampoline = 0x07f1;  /* br %r1 */
 217         if (nmi_alloc_per_cpu(lc))
 218                 goto out;
 219         if (vdso_alloc_per_cpu(lc))
 220                 goto out_mcesa;
 221         lowcore_ptr[cpu] = lc;
 222         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
 223         return 0;
 224
 225 out_mcesa:
 226         nmi_free_per_cpu(lc);
 227 out:
 228         if (pcpu != &pcpu_devices[0]) {
 229                 free_page(panic_stack);
 230                 free_pages(async_stack, ASYNC_ORDER);
 231                 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 232         }
 233         return -ENOMEM;
 234 }
 235
 236 #ifdef CONFIG_HOTPLUG_CPU
 237
 238 static void pcpu_free_lowcore(struct pcpu *pcpu)
 239 {
 240         pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
 241         lowcore_ptr[pcpu - pcpu_devices] = NULL;
 242         vdso_free_per_cpu(pcpu->lowcore);
 243         nmi_free_per_cpu(pcpu->lowcore);
 244         if (pcpu == &pcpu_devices[0])
 245                 return;
 246         free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
 247         free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
 248         free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
 249 }
 250
 251 #endif /* CONFIG_HOTPLUG_CPU */
 252
 253 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
 254 {
 255         struct lowcore *lc = pcpu->lowcore;
 256
 257         cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
 258         cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
 259         lc->cpu_nr = cpu;
 260         lc->spinlock_lockval = arch_spin_lockval(cpu);
 261         lc->spinlock_index = 0;
 262         lc->percpu_offset = __per_cpu_offset[cpu];
 263         lc->kernel_asce = S390_lowcore.kernel_asce;
 264         lc->machine_flags = S390_lowcore.machine_flags;
 265         lc->user_timer = lc->system_timer = lc->steal_timer = 0;
 266         __ctl_store(lc->cregs_save_area, 0, 15);
 267         save_access_regs((unsigned int *) lc->access_regs_save_area);
 268         memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
 269                sizeof(lc->stfle_fac_list));
 270         memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list,
 271                sizeof(lc->alt_stfle_fac_list));
 272         arch_spin_lock_setup(cpu);
 273 }
 274
 275 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 276 {
 277         struct lowcore *lc = pcpu->lowcore;
 278
 279         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 280                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 281         lc->current_task = (unsigned long) tsk;
 282         lc->lpp = LPP_MAGIC;
 283         lc->current_pid = tsk->pid;
 284         lc->user_timer = tsk->thread.user_timer;
 285         lc->guest_timer = tsk->thread.guest_timer;
 286         lc->system_timer = tsk->thread.system_timer;
 287         lc->hardirq_timer = tsk->thread.hardirq_timer;
 288         lc->softirq_timer = tsk->thread.softirq_timer;
 289         lc->steal_timer = 0;
 290 }
 291
 292 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 293 {
 294         struct lowcore *lc = pcpu->lowcore;
 295
 296         lc->restart_stack = lc->kernel_stack;
 297         lc->restart_fn = (unsigned long) func;
 298         lc->restart_data = (unsigned long) data;
 299         lc->restart_source = -1UL;
 300         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 301 }
 302
 303 /*
 304  * Call function via PSW restart on pcpu and stop the current cpu.
 305  */
 306 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 307                           void *data, unsigned long stack)
 308 {
 309         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 310         unsigned long source_cpu = stap();
 311
 312         __load_psw_mask(PSW_KERNEL_BITS);
 313         if (pcpu->address == source_cpu)
 314                 func(data);     /* should not return */
 315         /* Stop target cpu (if func returns this stops the current cpu). */
 316         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 317         /* Restart func on the target cpu and stop the current cpu. */
 318         mem_assign_absolute(lc->restart_stack, stack);
 319         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 320         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 321         mem_assign_absolute(lc->restart_source, source_cpu);
 322         __bpon();
 323         asm volatile(
 324                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 325                 "       brc     2,0b    # busy, try again\n"
 326                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 327                 "       brc     2,1b    # busy, try again\n"
 328                 : : "d" (pcpu->address), "d" (source_cpu),
 329                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 330                 : "0", "1", "cc");
 331         for (;;) ;
 332 }
 333
 334 /*
 335  * Enable additional logical cpus for multi-threading.
 336  */
 337 static int pcpu_set_smt(unsigned int mtid)
 338 {
 339         int cc;
 340
 341         if (smp_cpu_mtid == mtid)
 342                 return 0;
 343         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 344         if (cc == 0) {
 345                 smp_cpu_mtid = mtid;
 346                 smp_cpu_mt_shift = 0;
 347                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 348                         smp_cpu_mt_shift++;
 349                 pcpu_devices[0].address = stap();
 350         }
 351         return cc;
 352 }
 353
 354 /*
 355  * Call function on an online CPU.
 356  */
 357 void smp_call_online_cpu(void (*func)(void *), void *data)
 358 {
 359         struct pcpu *pcpu;
 360
 361         /* Use the current cpu if it is online. */
 362         pcpu = pcpu_find_address(cpu_online_mask, stap());
 363         if (!pcpu)
 364                 /* Use the first online cpu. */
 365                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 366         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 367 }
 368
 369 /*
 370  * Call function on the ipl CPU.
 371  */
 372 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 373 {
 374         pcpu_delegate(&pcpu_devices[0], func, data,
 375                       pcpu_devices->lowcore->panic_stack -
 376                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 377 }
 378
 379 int smp_find_processor_id(u16 address)
 380 {
 381         int cpu;
 382
 383         for_each_present_cpu(cpu)
 384                 if (pcpu_devices[cpu].address == address)
 385                         return cpu;
 386         return -1;
 387 }
 388
 389 bool arch_vcpu_is_preempted(int cpu)
 390 {
 391         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 392                 return false;
 393         if (pcpu_running(pcpu_devices + cpu))
 394                 return false;
 395         return true;
 396 }
 397 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 398
 399 void smp_yield_cpu(int cpu)
 400 {
 401         if (MACHINE_HAS_DIAG9C) {
 402                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 403                 asm volatile("diag %0,0,0x9c"
 404                              : : "d" (pcpu_devices[cpu].address));
 405         } else if (MACHINE_HAS_DIAG44) {
 406                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 407                 asm volatile("diag 0,0,0x44");
 408         }
 409 }
 410
 411 /*
 412  * Send cpus emergency shutdown signal. This gives the cpus the
 413  * opportunity to complete outstanding interrupts.
 414  */
 415 void notrace smp_emergency_stop(void)
 416 {
 417         cpumask_t cpumask;
 418         u64 end;
 419         int cpu;
 420
 421         cpumask_copy(&cpumask, cpu_online_mask);
 422         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 423
 424         end = get_tod_clock() + (1000000UL << 12);
 425         for_each_cpu(cpu, &cpumask) {
 426                 struct pcpu *pcpu = pcpu_devices + cpu;
 427                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 428                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 429                                    0, NULL) == SIGP_CC_BUSY &&
 430                        get_tod_clock() < end)
 431                         cpu_relax();
 432         }
 433         while (get_tod_clock() < end) {
 434                 for_each_cpu(cpu, &cpumask)
 435                         if (pcpu_stopped(pcpu_devices + cpu))
 436                                 cpumask_clear_cpu(cpu, &cpumask);
 437                 if (cpumask_empty(&cpumask))
 438                         break;
 439                 cpu_relax();
 440         }
 441 }
 442 NOKPROBE_SYMBOL(smp_emergency_stop);
 443
 444 /*
 445  * Stop all cpus but the current one.
 446  */
 447 void smp_send_stop(void)
 448 {
 449         int cpu;
 450
 451         /* Disable all interrupts/machine checks */
 452         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 453         trace_hardirqs_off();
 454
 455         debug_set_critical();
 456
 457         if (oops_in_progress)
 458                 smp_emergency_stop();
 459
 460         /* stop all processors */
 461         for_each_online_cpu(cpu) {
 462                 if (cpu == smp_processor_id())
 463                         continue;
 464                 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
 465                 while (!pcpu_stopped(pcpu_devices + cpu))
 466                         cpu_relax();
 467         }
 468 }
 469
 470 /*
 471  * This is the main routine where commands issued by other
 472  * cpus are handled.
 473  */
 474 static void smp_handle_ext_call(void)
 475 {
 476         unsigned long bits;
 477
 478         /* handle bit signal external calls */
 479         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 480         if (test_bit(ec_stop_cpu, &bits))
 481                 smp_stop_cpu();
 482         if (test_bit(ec_schedule, &bits))
 483                 scheduler_ipi();
 484         if (test_bit(ec_call_function_single, &bits))
 485                 generic_smp_call_function_single_interrupt();
 486 }
 487
 488 static void do_ext_call_interrupt(struct ext_code ext_code,
 489                                   unsigned int param32, unsigned long param64)
 490 {
 491         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 492         smp_handle_ext_call();
 493 }
 494
 495 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 496 {
 497         int cpu;
 498
 499         for_each_cpu(cpu, mask)
 500                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 501 }
 502
 503 void arch_send_call_function_single_ipi(int cpu)
 504 {
 505         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 506 }
 507
 508 /*
 509  * this function sends a 'reschedule' IPI to another CPU.
 510  * it goes straight through and wastes no time serializing
 511  * anything. Worst case is that we lose a reschedule ...
 512  */
 513 void smp_send_reschedule(int cpu)
 514 {
 515         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 516 }
 517
 518 /*
 519  * parameter area for the set/clear control bit callbacks
 520  */
 521 struct ec_creg_mask_parms {
 522         unsigned long orval;
 523         unsigned long andval;
 524         int cr;
 525 };
 526
 527 /*
 528  * callback for setting/clearing control bits
 529  */
 530 static void smp_ctl_bit_callback(void *info)
 531 {
 532         struct ec_creg_mask_parms *pp = info;
 533         unsigned long cregs[16];
 534
 535         __ctl_store(cregs, 0, 15);
 536         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 537         __ctl_load(cregs, 0, 15);
 538 }
 539
 540 /*
 541  * Set a bit in a control register of all cpus
 542  */
 543 void smp_ctl_set_bit(int cr, int bit)
 544 {
 545         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 546
 547         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 548 }
 549 EXPORT_SYMBOL(smp_ctl_set_bit);
 550
 551 /*
 552  * Clear a bit in a control register of all cpus
 553  */
 554 void smp_ctl_clear_bit(int cr, int bit)
 555 {
 556         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 557
 558         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 559 }
 560 EXPORT_SYMBOL(smp_ctl_clear_bit);
 561
 562 #ifdef CONFIG_CRASH_DUMP
 563
 564 int smp_store_status(int cpu)
 565 {
 566         struct pcpu *pcpu = pcpu_devices + cpu;
 567         unsigned long pa;
 568
 569         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 570         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 571                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 572                 return -EIO;
 573         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
 574                 return 0;
 575         pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
 576         if (MACHINE_HAS_GS)
 577                 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
 578         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 579                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 580                 return -EIO;
 581         return 0;
 582 }
 583
 584 /*
 585  * Collect CPU state of the previous, crashed system.
 586  * There are four cases:
 587  * 1) standard zfcp dump
 588  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 589  *    The state for all CPUs except the boot CPU needs to be collected
 590  *    with sigp stop-and-store-status. The boot CPU state is located in
 591  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 592  *    will copy the boot CPU state from the HSA.
 593  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 594  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 595  *    The state for all CPUs except the boot CPU needs to be collected
 596  *    with sigp stop-and-store-status. The firmware or the boot-loader
 597  *    stored the registers of the boot CPU in the absolute lowcore in the
 598  *    memory of the old system.
 599  * 3) kdump and the old kernel did not store the CPU state,
 600  *    or stand-alone kdump for DASD
 601  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 602  *    The state for all CPUs except the boot CPU needs to be collected
 603  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 604  *    stored the registers of the boot CPU in the memory of the old system.
 605  * 4) kdump and the old kernel stored the CPU state
 606  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 607  *    This case does not exist for s390 anymore, setup_arch explicitly
 608  *    deactivates the elfcorehdr= kernel parameter
 609  */
 610 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 611                                      bool is_boot_cpu, unsigned long page)
 612 {
 613         __vector128 *vxrs = (__vector128 *) page;
 614
 615         if (is_boot_cpu)
 616                 vxrs = boot_cpu_vector_save_area;
 617         else
 618                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 619         save_area_add_vxrs(sa, vxrs);
 620 }
 621
 622 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 623                                      bool is_boot_cpu, unsigned long page)
 624 {
 625         void *regs = (void *) page;
 626
 627         if (is_boot_cpu)
 628                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 629         else
 630                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 631         save_area_add_regs(sa, regs);
 632 }
 633
 634 void __init smp_save_dump_cpus(void)
 635 {
 636         int addr, boot_cpu_addr, max_cpu_addr;
 637         struct save_area *sa;
 638         unsigned long page;
 639         bool is_boot_cpu;
 640
 641         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 642                 /* No previous system present, normal boot. */
 643                 return;
 644         /* Allocate a page as dumping area for the store status sigps */
 645         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 646         /* Set multi-threading state to the previous system. */
 647         pcpu_set_smt(sclp.mtid_prev);
 648         boot_cpu_addr = stap();
 649         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 650         for (addr = 0; addr <= max_cpu_addr; addr++) {
 651                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 652                     SIGP_CC_NOT_OPERATIONAL)
 653                         continue;
 654                 is_boot_cpu = (addr == boot_cpu_addr);
 655                 /* Allocate save area */
 656                 sa = save_area_alloc(is_boot_cpu);
 657                 if (!sa)
 658                         panic("could not allocate memory for save area\n");
 659                 if (MACHINE_HAS_VX)
 660                         /* Get the vector registers */
 661                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 662                 /*
 663                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 664                  * of the boot CPU are stored in the HSA. To retrieve
 665                  * these registers an SCLP request is required which is
 666                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 667                  */
 668                 if (!is_boot_cpu || OLDMEM_BASE)
 669                         /* Get the CPU registers */
 670                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 671         }
 672         memblock_free(page, PAGE_SIZE);
 673         diag308_reset();
 674         pcpu_set_smt(0);
 675 }
 676 #endif /* CONFIG_CRASH_DUMP */
 677
 678 void smp_cpu_set_polarization(int cpu, int val)
 679 {
 680         pcpu_devices[cpu].polarization = val;
 681 }
 682
 683 int smp_cpu_get_polarization(int cpu)
 684 {
 685         return pcpu_devices[cpu].polarization;
 686 }
 687
 688 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 689 {
 690         static int use_sigp_detection;
 691         int address;
 692
 693         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 694                 use_sigp_detection = 1;
 695                 for (address = 0;
 696                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 697                      address += (1U << smp_cpu_mt_shift)) {
 698                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 699                             SIGP_CC_NOT_OPERATIONAL)
 700                                 continue;
 701                         info->core[info->configured].core_id =
 702                                 address >> smp_cpu_mt_shift;
 703                         info->configured++;
 704                 }
 705                 info->combined = info->configured;
 706         }
 707 }
 708
 709 static int smp_add_present_cpu(int cpu);
 710
 711 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 712 {
 713         struct pcpu *pcpu;
 714         cpumask_t avail;
 715         int cpu, nr, i, j;
 716         u16 address;
 717
 718         nr = 0;
 719         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 720         cpu = cpumask_first(&avail);
 721         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 722                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 723                         continue;
 724                 address = info->core[i].core_id << smp_cpu_mt_shift;
 725                 for (j = 0; j <= smp_cpu_mtid; j++) {
 726                         if (pcpu_find_address(cpu_present_mask, address + j))
 727                                 continue;
 728                         pcpu = pcpu_devices + cpu;
 729                         pcpu->address = address + j;
 730                         pcpu->state =
 731                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 732                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 733                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 734                         set_cpu_present(cpu, true);
 735                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 736                                 set_cpu_present(cpu, false);
 737                         else
 738                                 nr++;
 739                         cpu = cpumask_next(cpu, &avail);
 740                         if (cpu >= nr_cpu_ids)
 741                                 break;
 742                 }
 743         }
 744         return nr;
 745 }
 746
 747 void __init smp_detect_cpus(void)
 748 {
 749         unsigned int cpu, mtid, c_cpus, s_cpus;
 750         struct sclp_core_info *info;
 751         u16 address;
 752
 753         /* Get CPU information */
 754         info = memblock_virt_alloc(sizeof(*info), 8);
 755         smp_get_core_info(info, 1);
 756         /* Find boot CPU type */
 757         if (sclp.has_core_type) {
 758                 address = stap();
 759                 for (cpu = 0; cpu < info->combined; cpu++)
 760                         if (info->core[cpu].core_id == address) {
 761                                 /* The boot cpu dictates the cpu type. */
 762                                 boot_core_type = info->core[cpu].type;
 763                                 break;
 764                         }
 765                 if (cpu >= info->combined)
 766                         panic("Could not find boot CPU type");
 767         }
 768
 769         /* Set multi-threading state for the current system */
 770         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 771         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 772         pcpu_set_smt(mtid);
 773
 774         /* Print number of CPUs */
 775         c_cpus = s_cpus = 0;
 776         for (cpu = 0; cpu < info->combined; cpu++) {
 777                 if (sclp.has_core_type &&
 778                     info->core[cpu].type != boot_core_type)
 779                         continue;
 780                 if (cpu < info->configured)
 781                         c_cpus += smp_cpu_mtid + 1;
 782                 else
 783                         s_cpus += smp_cpu_mtid + 1;
 784         }
 785         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 786
 787         /* Add CPUs present at boot */
 788         get_online_cpus();
 789         __smp_rescan_cpus(info, 0);
 790         put_online_cpus();
 791         memblock_free_early((unsigned long)info, sizeof(*info));
 792 }
 793
 794 /*
 795  *      Activate a secondary processor.
 796  */
 797 static void smp_start_secondary(void *cpuvoid)
 798 {
 799         int cpu = smp_processor_id();
 800
 801         S390_lowcore.last_update_clock = get_tod_clock();
 802         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 803         S390_lowcore.restart_fn = (unsigned long) do_restart;
 804         S390_lowcore.restart_data = 0;
 805         S390_lowcore.restart_source = -1UL;
 806         restore_access_regs(S390_lowcore.access_regs_save_area);
 807         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 808         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 809         cpu_init();
 810         preempt_disable();
 811         init_cpu_timer();
 812         vtime_init();
 813         pfault_init();
 814         notify_cpu_starting(cpu);
 815         if (topology_cpu_dedicated(cpu))
 816                 set_cpu_flag(CIF_DEDICATED_CPU);
 817         else
 818                 clear_cpu_flag(CIF_DEDICATED_CPU);
 819         set_cpu_online(cpu, true);
 820         inc_irq_stat(CPU_RST);
 821         local_irq_enable();
 822         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 823 }
 824
 825 /* Upping and downing of CPUs */
 826 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 827 {
 828         struct pcpu *pcpu;
 829         int base, i, rc;
 830
 831         pcpu = pcpu_devices + cpu;
 832         if (pcpu->state != CPU_STATE_CONFIGURED)
 833                 return -EIO;
 834         base = smp_get_base_cpu(cpu);
 835         for (i = 0; i <= smp_cpu_mtid; i++) {
 836                 if (base + i < nr_cpu_ids)
 837                         if (cpu_online(base + i))
 838                                 break;
 839         }
 840         /*
 841          * If this is the first CPU of the core to get online
 842          * do an initial CPU reset.
 843          */
 844         if (i > smp_cpu_mtid &&
 845             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 846             SIGP_CC_ORDER_CODE_ACCEPTED)
 847                 return -EIO;
 848
 849         rc = pcpu_alloc_lowcore(pcpu, cpu);
 850         if (rc)
 851                 return rc;
 852         pcpu_prepare_secondary(pcpu, cpu);
 853         pcpu_attach_task(pcpu, tidle);
 854         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 855         /* Wait until cpu puts itself in the online & active maps */
 856         while (!cpu_online(cpu))
 857                 cpu_relax();
 858         return 0;
 859 }
 860
 861 static unsigned int setup_possible_cpus __initdata;
 862
 863 static int __init _setup_possible_cpus(char *s)
 864 {
 865         get_option(&s, &setup_possible_cpus);
 866         return 0;
 867 }
 868 early_param("possible_cpus", _setup_possible_cpus);
 869
 870 #ifdef CONFIG_HOTPLUG_CPU
 871
 872 int __cpu_disable(void)
 873 {
 874         unsigned long cregs[16];
 875
 876         /* Handle possible pending IPIs */
 877         smp_handle_ext_call();
 878         set_cpu_online(smp_processor_id(), false);
 879         /* Disable pseudo page faults on this cpu. */
 880         pfault_fini();
 881         /* Disable interrupt sources via control register. */
 882         __ctl_store(cregs, 0, 15);
 883         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 884         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 885         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 886         __ctl_load(cregs, 0, 15);
 887         clear_cpu_flag(CIF_NOHZ_DELAY);
 888         return 0;
 889 }
 890
 891 void __cpu_die(unsigned int cpu)
 892 {
 893         struct pcpu *pcpu;
 894
 895         /* Wait until target cpu is down */
 896         pcpu = pcpu_devices + cpu;
 897         while (!pcpu_stopped(pcpu))
 898                 cpu_relax();
 899         pcpu_free_lowcore(pcpu);
 900         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 901         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 902 }
 903
 904 void __noreturn cpu_die(void)
 905 {
 906         idle_task_exit();
 907         __bpon();
 908         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 909         for (;;) ;
 910 }
 911
 912 #endif /* CONFIG_HOTPLUG_CPU */
 913
 914 void __init smp_fill_possible_mask(void)
 915 {
 916         unsigned int possible, sclp_max, cpu;
 917
 918         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 919         sclp_max = min(smp_max_threads, sclp_max);
 920         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 921         possible = setup_possible_cpus ?: nr_cpu_ids;
 922         possible = min(possible, sclp_max);
 923         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 924                 set_cpu_possible(cpu, true);
 925 }
 926
 927 void __init smp_prepare_cpus(unsigned int max_cpus)
 928 {
 929         /* request the 0x1201 emergency signal external interrupt */
 930         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 931                 panic("Couldn't request external interrupt 0x1201");
 932         /* request the 0x1202 external call external interrupt */
 933         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 934                 panic("Couldn't request external interrupt 0x1202");
 935 }
 936
 937 void __init smp_prepare_boot_cpu(void)
 938 {
 939         struct pcpu *pcpu = pcpu_devices;
 940
 941         WARN_ON(!cpu_present(0) || !cpu_online(0));
 942         pcpu->state = CPU_STATE_CONFIGURED;
 943         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 944         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 945         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 946 }
 947
 948 void __init smp_cpus_done(unsigned int max_cpus)
 949 {
 950 }
 951
 952 void __init smp_setup_processor_id(void)
 953 {
 954         pcpu_devices[0].address = stap();
 955         S390_lowcore.cpu_nr = 0;
 956         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 957         S390_lowcore.spinlock_index = 0;
 958 }
 959
 960 /*
 961  * the frequency of the profiling timer can be changed
 962  * by writing a multiplier value into /proc/profile.
 963  *
 964  * usually you want to run this on all CPUs ;)
 965  */
 966 int setup_profiling_timer(unsigned int multiplier)
 967 {
 968         return 0;
 969 }
 970
 971 #ifdef CONFIG_HOTPLUG_CPU
 972 static ssize_t cpu_configure_show(struct device *dev,
 973                                   struct device_attribute *attr, char *buf)
 974 {
 975         ssize_t count;
 976
 977         mutex_lock(&smp_cpu_state_mutex);
 978         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 979         mutex_unlock(&smp_cpu_state_mutex);
 980         return count;
 981 }
 982
 983 static ssize_t cpu_configure_store(struct device *dev,
 984                                    struct device_attribute *attr,
 985                                    const char *buf, size_t count)
 986 {
 987         struct pcpu *pcpu;
 988         int cpu, val, rc, i;
 989         char delim;
 990
 991         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 992                 return -EINVAL;
 993         if (val != 0 && val != 1)
 994                 return -EINVAL;
 995         get_online_cpus();
 996         mutex_lock(&smp_cpu_state_mutex);
 997         rc = -EBUSY;
 998         /* disallow configuration changes of online cpus and cpu 0 */
 999         cpu = dev->id;
1000         cpu = smp_get_base_cpu(cpu);
1001         if (cpu == 0)
1002                 goto out;
1003         for (i = 0; i <= smp_cpu_mtid; i++)
1004                 if (cpu_online(cpu + i))
1005                         goto out;
1006         pcpu = pcpu_devices + cpu;
1007         rc = 0;
1008         switch (val) {
1009         case 0:
1010                 if (pcpu->state != CPU_STATE_CONFIGURED)
1011                         break;
1012                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1013                 if (rc)
1014                         break;
1015                 for (i = 0; i <= smp_cpu_mtid; i++) {
1016                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1017                                 continue;
1018                         pcpu[i].state = CPU_STATE_STANDBY;
1019                         smp_cpu_set_polarization(cpu + i,
1020                                                  POLARIZATION_UNKNOWN);
1021                 }
1022                 topology_expect_change();
1023                 break;
1024         case 1:
1025                 if (pcpu->state != CPU_STATE_STANDBY)
1026                         break;
1027                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1028                 if (rc)
1029                         break;
1030                 for (i = 0; i <= smp_cpu_mtid; i++) {
1031                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1032                                 continue;
1033                         pcpu[i].state = CPU_STATE_CONFIGURED;
1034                         smp_cpu_set_polarization(cpu + i,
1035                                                  POLARIZATION_UNKNOWN);
1036                 }
1037                 topology_expect_change();
1038                 break;
1039         default:
1040                 break;
1041         }
1042 out:
1043         mutex_unlock(&smp_cpu_state_mutex);
1044         put_online_cpus();
1045         return rc ? rc : count;
1046 }
1047 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1048 #endif /* CONFIG_HOTPLUG_CPU */
1049
1050 static ssize_t show_cpu_address(struct device *dev,
1051                                 struct device_attribute *attr, char *buf)
1052 {
1053         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1054 }
1055 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1056
1057 static struct attribute *cpu_common_attrs[] = {
1058 #ifdef CONFIG_HOTPLUG_CPU
1059         &dev_attr_configure.attr,
1060 #endif
1061         &dev_attr_address.attr,
1062         NULL,
1063 };
1064
1065 static struct attribute_group cpu_common_attr_group = {
1066         .attrs = cpu_common_attrs,
1067 };
1068
1069 static struct attribute *cpu_online_attrs[] = {
1070         &dev_attr_idle_count.attr,
1071         &dev_attr_idle_time_us.attr,
1072         NULL,
1073 };
1074
1075 static struct attribute_group cpu_online_attr_group = {
1076         .attrs = cpu_online_attrs,
1077 };
1078
1079 static int smp_cpu_online(unsigned int cpu)
1080 {
1081         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1082
1083         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1084 }
1085 static int smp_cpu_pre_down(unsigned int cpu)
1086 {
1087         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1088
1089         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1090         return 0;
1091 }
1092
1093 static int smp_add_present_cpu(int cpu)
1094 {
1095         struct device *s;
1096         struct cpu *c;
1097         int rc;
1098
1099         c = kzalloc(sizeof(*c), GFP_KERNEL);
1100         if (!c)
1101                 return -ENOMEM;
1102         per_cpu(cpu_device, cpu) = c;
1103         s = &c->dev;
1104         c->hotpluggable = 1;
1105         rc = register_cpu(c, cpu);
1106         if (rc)
1107                 goto out;
1108         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1109         if (rc)
1110                 goto out_cpu;
1111         rc = topology_cpu_init(c);
1112         if (rc)
1113                 goto out_topology;
1114         return 0;
1115
1116 out_topology:
1117         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1118 out_cpu:
1119 #ifdef CONFIG_HOTPLUG_CPU
1120         unregister_cpu(c);
1121 #endif
1122 out:
1123         return rc;
1124 }
1125
1126 #ifdef CONFIG_HOTPLUG_CPU
1127
1128 int __ref smp_rescan_cpus(void)
1129 {
1130         struct sclp_core_info *info;
1131         int nr;
1132
1133         info = kzalloc(sizeof(*info), GFP_KERNEL);
1134         if (!info)
1135                 return -ENOMEM;
1136         smp_get_core_info(info, 0);
1137         get_online_cpus();
1138         mutex_lock(&smp_cpu_state_mutex);
1139         nr = __smp_rescan_cpus(info, 1);
1140         mutex_unlock(&smp_cpu_state_mutex);
1141         put_online_cpus();
1142         kfree(info);
1143         if (nr)
1144                 topology_schedule_update();
1145         return 0;
1146 }
1147
1148 static ssize_t __ref rescan_store(struct device *dev,
1149                                   struct device_attribute *attr,
1150                                   const char *buf,
1151                                   size_t count)
1152 {
1153         int rc;
1154
1155         rc = smp_rescan_cpus();
1156         return rc ? rc : count;
1157 }
1158 static DEVICE_ATTR_WO(rescan);
1159 #endif /* CONFIG_HOTPLUG_CPU */
1160
1161 static int __init s390_smp_init(void)
1162 {
1163         int cpu, rc = 0;
1164
1165 #ifdef CONFIG_HOTPLUG_CPU
1166         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1167         if (rc)
1168                 return rc;
1169 #endif
1170         for_each_present_cpu(cpu) {
1171                 rc = smp_add_present_cpu(cpu);
1172                 if (rc)
1173                         goto out;
1174         }
1175
1176         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1177                                smp_cpu_online, smp_cpu_pre_down);
1178         rc = rc <= 0 ? rc : 0;
1179 out:
1180         return rc;
1181 }
1182 subsys_initcall(s390_smp_init);