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