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 <asm/topology.h>
  59 #include "entry.h"
  60
  61 enum {
  62         ec_schedule = 0,
  63         ec_call_function_single,
  64         ec_stop_cpu,
  65 };
  66
  67 enum {
  68         CPU_STATE_STANDBY,
  69         CPU_STATE_CONFIGURED,
  70 };
  71
  72 static DEFINE_PER_CPU(struct cpu *, cpu_device);
  73
  74 struct pcpu {
  75         struct lowcore *lowcore;        /* lowcore page(s) for the cpu */
  76         unsigned long ec_mask;          /* bit mask for ec_xxx functions */
  77         unsigned long ec_clk;           /* sigp timestamp for ec_xxx */
  78         signed char state;              /* physical cpu state */
  79         signed char polarization;       /* physical polarization */
  80         u16 address;                    /* physical cpu address */
  81 };
  82
  83 static u8 boot_core_type;
  84 static struct pcpu pcpu_devices[NR_CPUS];
  85
  86 unsigned int smp_cpu_mt_shift;
  87 EXPORT_SYMBOL(smp_cpu_mt_shift);
  88
  89 unsigned int smp_cpu_mtid;
  90 EXPORT_SYMBOL(smp_cpu_mtid);
  91
  92 #ifdef CONFIG_CRASH_DUMP
  93 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
  94 #endif
  95
  96 static unsigned int smp_max_threads __initdata = -1U;
  97
  98 static int __init early_nosmt(char *s)
  99 {
 100         smp_max_threads = 1;
 101         return 0;
 102 }
 103 early_param("nosmt", early_nosmt);
 104
 105 static int __init early_smt(char *s)
 106 {
 107         get_option(&s, &smp_max_threads);
 108         return 0;
 109 }
 110 early_param("smt", early_smt);
 111
 112 /*
 113  * The smp_cpu_state_mutex must be held when changing the state or polarization
 114  * member of a pcpu data structure within the pcpu_devices arreay.
 115  */
 116 DEFINE_MUTEX(smp_cpu_state_mutex);
 117
 118 /*
 119  * Signal processor helper functions.
 120  */
 121 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
 122 {
 123         int cc;
 124
 125         while (1) {
 126                 cc = __pcpu_sigp(addr, order, parm, NULL);
 127                 if (cc != SIGP_CC_BUSY)
 128                         return cc;
 129                 cpu_relax();
 130         }
 131 }
 132
 133 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
 134 {
 135         int cc, retry;
 136
 137         for (retry = 0; ; retry++) {
 138                 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
 139                 if (cc != SIGP_CC_BUSY)
 140                         break;
 141                 if (retry >= 3)
 142                         udelay(10);
 143         }
 144         return cc;
 145 }
 146
 147 static inline int pcpu_stopped(struct pcpu *pcpu)
 148 {
 149         u32 uninitialized_var(status);
 150
 151         if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
 152                         0, &status) != SIGP_CC_STATUS_STORED)
 153                 return 0;
 154         return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
 155 }
 156
 157 static inline int pcpu_running(struct pcpu *pcpu)
 158 {
 159         if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
 160                         0, NULL) != SIGP_CC_STATUS_STORED)
 161                 return 1;
 162         /* Status stored condition code is equivalent to cpu not running. */
 163         return 0;
 164 }
 165
 166 /*
 167  * Find struct pcpu by cpu address.
 168  */
 169 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
 170 {
 171         int cpu;
 172
 173         for_each_cpu(cpu, mask)
 174                 if (pcpu_devices[cpu].address == address)
 175                         return pcpu_devices + cpu;
 176         return NULL;
 177 }
 178
 179 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
 180 {
 181         int order;
 182
 183         if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
 184                 return;
 185         order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
 186         pcpu->ec_clk = get_tod_clock_fast();
 187         pcpu_sigp_retry(pcpu, order, 0);
 188 }
 189
 190 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 191 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
 192
 193 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
 194 {
 195         unsigned long async_stack, panic_stack;
 196         struct lowcore *lc;
 197
 198         if (pcpu != &pcpu_devices[0]) {
 199                 pcpu->lowcore = (struct lowcore *)
 200                         __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
 201                 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
 202                 panic_stack = __get_free_page(GFP_KERNEL);
 203                 if (!pcpu->lowcore || !panic_stack || !async_stack)
 204                         goto out;
 205         } else {
 206                 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
 207                 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
 208         }
 209         lc = pcpu->lowcore;
 210         memcpy(lc, &S390_lowcore, 512);
 211         memset((char *) lc + 512, 0, sizeof(*lc) - 512);
 212         lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
 213         lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
 214         lc->cpu_nr = cpu;
 215         lc->spinlock_lockval = arch_spin_lockval(cpu);
 216         lc->spinlock_index = 0;
 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                MAX_FACILITY_BIT/8);
 270         arch_spin_lock_setup(cpu);
 271 }
 272
 273 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 274 {
 275         struct lowcore *lc = pcpu->lowcore;
 276
 277         lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 278                 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
 279         lc->current_task = (unsigned long) tsk;
 280         lc->lpp = LPP_MAGIC;
 281         lc->current_pid = tsk->pid;
 282         lc->user_timer = tsk->thread.user_timer;
 283         lc->guest_timer = tsk->thread.guest_timer;
 284         lc->system_timer = tsk->thread.system_timer;
 285         lc->hardirq_timer = tsk->thread.hardirq_timer;
 286         lc->softirq_timer = tsk->thread.softirq_timer;
 287         lc->steal_timer = 0;
 288 }
 289
 290 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
 291 {
 292         struct lowcore *lc = pcpu->lowcore;
 293
 294         lc->restart_stack = lc->kernel_stack;
 295         lc->restart_fn = (unsigned long) func;
 296         lc->restart_data = (unsigned long) data;
 297         lc->restart_source = -1UL;
 298         pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
 299 }
 300
 301 /*
 302  * Call function via PSW restart on pcpu and stop the current cpu.
 303  */
 304 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 305                           void *data, unsigned long stack)
 306 {
 307         struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 308         unsigned long source_cpu = stap();
 309
 310         __load_psw_mask(PSW_KERNEL_BITS);
 311         if (pcpu->address == source_cpu)
 312                 func(data);     /* should not return */
 313         /* Stop target cpu (if func returns this stops the current cpu). */
 314         pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
 315         /* Restart func on the target cpu and stop the current cpu. */
 316         mem_assign_absolute(lc->restart_stack, stack);
 317         mem_assign_absolute(lc->restart_fn, (unsigned long) func);
 318         mem_assign_absolute(lc->restart_data, (unsigned long) data);
 319         mem_assign_absolute(lc->restart_source, source_cpu);
 320         asm volatile(
 321                 "0:     sigp    0,%0,%2 # sigp restart to target cpu\n"
 322                 "       brc     2,0b    # busy, try again\n"
 323                 "1:     sigp    0,%1,%3 # sigp stop to current cpu\n"
 324                 "       brc     2,1b    # busy, try again\n"
 325                 : : "d" (pcpu->address), "d" (source_cpu),
 326                     "K" (SIGP_RESTART), "K" (SIGP_STOP)
 327                 : "0", "1", "cc");
 328         for (;;) ;
 329 }
 330
 331 /*
 332  * Enable additional logical cpus for multi-threading.
 333  */
 334 static int pcpu_set_smt(unsigned int mtid)
 335 {
 336         int cc;
 337
 338         if (smp_cpu_mtid == mtid)
 339                 return 0;
 340         cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
 341         if (cc == 0) {
 342                 smp_cpu_mtid = mtid;
 343                 smp_cpu_mt_shift = 0;
 344                 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
 345                         smp_cpu_mt_shift++;
 346                 pcpu_devices[0].address = stap();
 347         }
 348         return cc;
 349 }
 350
 351 /*
 352  * Call function on an online CPU.
 353  */
 354 void smp_call_online_cpu(void (*func)(void *), void *data)
 355 {
 356         struct pcpu *pcpu;
 357
 358         /* Use the current cpu if it is online. */
 359         pcpu = pcpu_find_address(cpu_online_mask, stap());
 360         if (!pcpu)
 361                 /* Use the first online cpu. */
 362                 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
 363         pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
 364 }
 365
 366 /*
 367  * Call function on the ipl CPU.
 368  */
 369 void smp_call_ipl_cpu(void (*func)(void *), void *data)
 370 {
 371         pcpu_delegate(&pcpu_devices[0], func, data,
 372                       pcpu_devices->lowcore->panic_stack -
 373                       PANIC_FRAME_OFFSET + PAGE_SIZE);
 374 }
 375
 376 int smp_find_processor_id(u16 address)
 377 {
 378         int cpu;
 379
 380         for_each_present_cpu(cpu)
 381                 if (pcpu_devices[cpu].address == address)
 382                         return cpu;
 383         return -1;
 384 }
 385
 386 bool arch_vcpu_is_preempted(int cpu)
 387 {
 388         if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
 389                 return false;
 390         if (pcpu_running(pcpu_devices + cpu))
 391                 return false;
 392         return true;
 393 }
 394 EXPORT_SYMBOL(arch_vcpu_is_preempted);
 395
 396 void smp_yield_cpu(int cpu)
 397 {
 398         if (MACHINE_HAS_DIAG9C) {
 399                 diag_stat_inc_norecursion(DIAG_STAT_X09C);
 400                 asm volatile("diag %0,0,0x9c"
 401                              : : "d" (pcpu_devices[cpu].address));
 402         } else if (MACHINE_HAS_DIAG44) {
 403                 diag_stat_inc_norecursion(DIAG_STAT_X044);
 404                 asm volatile("diag 0,0,0x44");
 405         }
 406 }
 407
 408 /*
 409  * Send cpus emergency shutdown signal. This gives the cpus the
 410  * opportunity to complete outstanding interrupts.
 411  */
 412 void notrace smp_emergency_stop(void)
 413 {
 414         cpumask_t cpumask;
 415         u64 end;
 416         int cpu;
 417
 418         cpumask_copy(&cpumask, cpu_online_mask);
 419         cpumask_clear_cpu(smp_processor_id(), &cpumask);
 420
 421         end = get_tod_clock() + (1000000UL << 12);
 422         for_each_cpu(cpu, &cpumask) {
 423                 struct pcpu *pcpu = pcpu_devices + cpu;
 424                 set_bit(ec_stop_cpu, &pcpu->ec_mask);
 425                 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
 426                                    0, NULL) == SIGP_CC_BUSY &&
 427                        get_tod_clock() < end)
 428                         cpu_relax();
 429         }
 430         while (get_tod_clock() < end) {
 431                 for_each_cpu(cpu, &cpumask)
 432                         if (pcpu_stopped(pcpu_devices + cpu))
 433                                 cpumask_clear_cpu(cpu, &cpumask);
 434                 if (cpumask_empty(&cpumask))
 435                         break;
 436                 cpu_relax();
 437         }
 438 }
 439 NOKPROBE_SYMBOL(smp_emergency_stop);
 440
 441 /*
 442  * Stop all cpus but the current one.
 443  */
 444 void smp_send_stop(void)
 445 {
 446         int cpu;
 447
 448         /* Disable all interrupts/machine checks */
 449         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 450         trace_hardirqs_off();
 451
 452         debug_set_critical();
 453
 454         if (oops_in_progress)
 455                 smp_emergency_stop();
 456
 457         /* stop all processors */
 458         for_each_online_cpu(cpu) {
 459                 if (cpu == smp_processor_id())
 460                         continue;
 461                 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
 462                 while (!pcpu_stopped(pcpu_devices + cpu))
 463                         cpu_relax();
 464         }
 465 }
 466
 467 /*
 468  * This is the main routine where commands issued by other
 469  * cpus are handled.
 470  */
 471 static void smp_handle_ext_call(void)
 472 {
 473         unsigned long bits;
 474
 475         /* handle bit signal external calls */
 476         bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
 477         if (test_bit(ec_stop_cpu, &bits))
 478                 smp_stop_cpu();
 479         if (test_bit(ec_schedule, &bits))
 480                 scheduler_ipi();
 481         if (test_bit(ec_call_function_single, &bits))
 482                 generic_smp_call_function_single_interrupt();
 483 }
 484
 485 static void do_ext_call_interrupt(struct ext_code ext_code,
 486                                   unsigned int param32, unsigned long param64)
 487 {
 488         inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
 489         smp_handle_ext_call();
 490 }
 491
 492 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 493 {
 494         int cpu;
 495
 496         for_each_cpu(cpu, mask)
 497                 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 498 }
 499
 500 void arch_send_call_function_single_ipi(int cpu)
 501 {
 502         pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
 503 }
 504
 505 /*
 506  * this function sends a 'reschedule' IPI to another CPU.
 507  * it goes straight through and wastes no time serializing
 508  * anything. Worst case is that we lose a reschedule ...
 509  */
 510 void smp_send_reschedule(int cpu)
 511 {
 512         pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 513 }
 514
 515 /*
 516  * parameter area for the set/clear control bit callbacks
 517  */
 518 struct ec_creg_mask_parms {
 519         unsigned long orval;
 520         unsigned long andval;
 521         int cr;
 522 };
 523
 524 /*
 525  * callback for setting/clearing control bits
 526  */
 527 static void smp_ctl_bit_callback(void *info)
 528 {
 529         struct ec_creg_mask_parms *pp = info;
 530         unsigned long cregs[16];
 531
 532         __ctl_store(cregs, 0, 15);
 533         cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
 534         __ctl_load(cregs, 0, 15);
 535 }
 536
 537 /*
 538  * Set a bit in a control register of all cpus
 539  */
 540 void smp_ctl_set_bit(int cr, int bit)
 541 {
 542         struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
 543
 544         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 545 }
 546 EXPORT_SYMBOL(smp_ctl_set_bit);
 547
 548 /*
 549  * Clear a bit in a control register of all cpus
 550  */
 551 void smp_ctl_clear_bit(int cr, int bit)
 552 {
 553         struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
 554
 555         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
 556 }
 557 EXPORT_SYMBOL(smp_ctl_clear_bit);
 558
 559 #ifdef CONFIG_CRASH_DUMP
 560
 561 int smp_store_status(int cpu)
 562 {
 563         struct pcpu *pcpu = pcpu_devices + cpu;
 564         unsigned long pa;
 565
 566         pa = __pa(&pcpu->lowcore->floating_pt_save_area);
 567         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
 568                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 569                 return -EIO;
 570         if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
 571                 return 0;
 572         pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
 573         if (MACHINE_HAS_GS)
 574                 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
 575         if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
 576                               pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
 577                 return -EIO;
 578         return 0;
 579 }
 580
 581 /*
 582  * Collect CPU state of the previous, crashed system.
 583  * There are four cases:
 584  * 1) standard zfcp dump
 585  *    condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 586  *    The state for all CPUs except the boot CPU needs to be collected
 587  *    with sigp stop-and-store-status. The boot CPU state is located in
 588  *    the absolute lowcore of the memory stored in the HSA. The zcore code
 589  *    will copy the boot CPU state from the HSA.
 590  * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
 591  *    condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
 592  *    The state for all CPUs except the boot CPU needs to be collected
 593  *    with sigp stop-and-store-status. The firmware or the boot-loader
 594  *    stored the registers of the boot CPU in the absolute lowcore in the
 595  *    memory of the old system.
 596  * 3) kdump and the old kernel did not store the CPU state,
 597  *    or stand-alone kdump for DASD
 598  *    condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
 599  *    The state for all CPUs except the boot CPU needs to be collected
 600  *    with sigp stop-and-store-status. The kexec code or the boot-loader
 601  *    stored the registers of the boot CPU in the memory of the old system.
 602  * 4) kdump and the old kernel stored the CPU state
 603  *    condition: OLDMEM_BASE != NULL && is_kdump_kernel()
 604  *    This case does not exist for s390 anymore, setup_arch explicitly
 605  *    deactivates the elfcorehdr= kernel parameter
 606  */
 607 static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
 608                                      bool is_boot_cpu, unsigned long page)
 609 {
 610         __vector128 *vxrs = (__vector128 *) page;
 611
 612         if (is_boot_cpu)
 613                 vxrs = boot_cpu_vector_save_area;
 614         else
 615                 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
 616         save_area_add_vxrs(sa, vxrs);
 617 }
 618
 619 static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
 620                                      bool is_boot_cpu, unsigned long page)
 621 {
 622         void *regs = (void *) page;
 623
 624         if (is_boot_cpu)
 625                 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
 626         else
 627                 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
 628         save_area_add_regs(sa, regs);
 629 }
 630
 631 void __init smp_save_dump_cpus(void)
 632 {
 633         int addr, boot_cpu_addr, max_cpu_addr;
 634         struct save_area *sa;
 635         unsigned long page;
 636         bool is_boot_cpu;
 637
 638         if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
 639                 /* No previous system present, normal boot. */
 640                 return;
 641         /* Allocate a page as dumping area for the store status sigps */
 642         page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
 643         /* Set multi-threading state to the previous system. */
 644         pcpu_set_smt(sclp.mtid_prev);
 645         boot_cpu_addr = stap();
 646         max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
 647         for (addr = 0; addr <= max_cpu_addr; addr++) {
 648                 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
 649                     SIGP_CC_NOT_OPERATIONAL)
 650                         continue;
 651                 is_boot_cpu = (addr == boot_cpu_addr);
 652                 /* Allocate save area */
 653                 sa = save_area_alloc(is_boot_cpu);
 654                 if (!sa)
 655                         panic("could not allocate memory for save area\n");
 656                 if (MACHINE_HAS_VX)
 657                         /* Get the vector registers */
 658                         smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
 659                 /*
 660                  * For a zfcp dump OLDMEM_BASE == NULL and the registers
 661                  * of the boot CPU are stored in the HSA. To retrieve
 662                  * these registers an SCLP request is required which is
 663                  * done by drivers/s390/char/zcore.c:init_cpu_info()
 664                  */
 665                 if (!is_boot_cpu || OLDMEM_BASE)
 666                         /* Get the CPU registers */
 667                         smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
 668         }
 669         memblock_free(page, PAGE_SIZE);
 670         diag308_reset();
 671         pcpu_set_smt(0);
 672 }
 673 #endif /* CONFIG_CRASH_DUMP */
 674
 675 void smp_cpu_set_polarization(int cpu, int val)
 676 {
 677         pcpu_devices[cpu].polarization = val;
 678 }
 679
 680 int smp_cpu_get_polarization(int cpu)
 681 {
 682         return pcpu_devices[cpu].polarization;
 683 }
 684
 685 static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
 686 {
 687         static int use_sigp_detection;
 688         int address;
 689
 690         if (use_sigp_detection || sclp_get_core_info(info, early)) {
 691                 use_sigp_detection = 1;
 692                 for (address = 0;
 693                      address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
 694                      address += (1U << smp_cpu_mt_shift)) {
 695                         if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
 696                             SIGP_CC_NOT_OPERATIONAL)
 697                                 continue;
 698                         info->core[info->configured].core_id =
 699                                 address >> smp_cpu_mt_shift;
 700                         info->configured++;
 701                 }
 702                 info->combined = info->configured;
 703         }
 704 }
 705
 706 static int smp_add_present_cpu(int cpu);
 707
 708 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
 709 {
 710         struct pcpu *pcpu;
 711         cpumask_t avail;
 712         int cpu, nr, i, j;
 713         u16 address;
 714
 715         nr = 0;
 716         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 717         cpu = cpumask_first(&avail);
 718         for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
 719                 if (sclp.has_core_type && info->core[i].type != boot_core_type)
 720                         continue;
 721                 address = info->core[i].core_id << smp_cpu_mt_shift;
 722                 for (j = 0; j <= smp_cpu_mtid; j++) {
 723                         if (pcpu_find_address(cpu_present_mask, address + j))
 724                                 continue;
 725                         pcpu = pcpu_devices + cpu;
 726                         pcpu->address = address + j;
 727                         pcpu->state =
 728                                 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
 729                                 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
 730                         smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
 731                         set_cpu_present(cpu, true);
 732                         if (sysfs_add && smp_add_present_cpu(cpu) != 0)
 733                                 set_cpu_present(cpu, false);
 734                         else
 735                                 nr++;
 736                         cpu = cpumask_next(cpu, &avail);
 737                         if (cpu >= nr_cpu_ids)
 738                                 break;
 739                 }
 740         }
 741         return nr;
 742 }
 743
 744 void __init smp_detect_cpus(void)
 745 {
 746         unsigned int cpu, mtid, c_cpus, s_cpus;
 747         struct sclp_core_info *info;
 748         u16 address;
 749
 750         /* Get CPU information */
 751         info = memblock_virt_alloc(sizeof(*info), 8);
 752         smp_get_core_info(info, 1);
 753         /* Find boot CPU type */
 754         if (sclp.has_core_type) {
 755                 address = stap();
 756                 for (cpu = 0; cpu < info->combined; cpu++)
 757                         if (info->core[cpu].core_id == address) {
 758                                 /* The boot cpu dictates the cpu type. */
 759                                 boot_core_type = info->core[cpu].type;
 760                                 break;
 761                         }
 762                 if (cpu >= info->combined)
 763                         panic("Could not find boot CPU type");
 764         }
 765
 766         /* Set multi-threading state for the current system */
 767         mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
 768         mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
 769         pcpu_set_smt(mtid);
 770
 771         /* Print number of CPUs */
 772         c_cpus = s_cpus = 0;
 773         for (cpu = 0; cpu < info->combined; cpu++) {
 774                 if (sclp.has_core_type &&
 775                     info->core[cpu].type != boot_core_type)
 776                         continue;
 777                 if (cpu < info->configured)
 778                         c_cpus += smp_cpu_mtid + 1;
 779                 else
 780                         s_cpus += smp_cpu_mtid + 1;
 781         }
 782         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 783
 784         /* Add CPUs present at boot */
 785         get_online_cpus();
 786         __smp_rescan_cpus(info, 0);
 787         put_online_cpus();
 788         memblock_free_early((unsigned long)info, sizeof(*info));
 789 }
 790
 791 /*
 792  *      Activate a secondary processor.
 793  */
 794 static void smp_start_secondary(void *cpuvoid)
 795 {
 796         int cpu = smp_processor_id();
 797
 798         S390_lowcore.last_update_clock = get_tod_clock();
 799         S390_lowcore.restart_stack = (unsigned long) restart_stack;
 800         S390_lowcore.restart_fn = (unsigned long) do_restart;
 801         S390_lowcore.restart_data = 0;
 802         S390_lowcore.restart_source = -1UL;
 803         restore_access_regs(S390_lowcore.access_regs_save_area);
 804         __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
 805         __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 806         cpu_init();
 807         preempt_disable();
 808         init_cpu_timer();
 809         vtime_init();
 810         pfault_init();
 811         notify_cpu_starting(cpu);
 812         if (topology_cpu_dedicated(cpu))
 813                 set_cpu_flag(CIF_DEDICATED_CPU);
 814         else
 815                 clear_cpu_flag(CIF_DEDICATED_CPU);
 816         set_cpu_online(cpu, true);
 817         inc_irq_stat(CPU_RST);
 818         local_irq_enable();
 819         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 820 }
 821
 822 /* Upping and downing of CPUs */
 823 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
 824 {
 825         struct pcpu *pcpu;
 826         int base, i, rc;
 827
 828         pcpu = pcpu_devices + cpu;
 829         if (pcpu->state != CPU_STATE_CONFIGURED)
 830                 return -EIO;
 831         base = smp_get_base_cpu(cpu);
 832         for (i = 0; i <= smp_cpu_mtid; i++) {
 833                 if (base + i < nr_cpu_ids)
 834                         if (cpu_online(base + i))
 835                                 break;
 836         }
 837         /*
 838          * If this is the first CPU of the core to get online
 839          * do an initial CPU reset.
 840          */
 841         if (i > smp_cpu_mtid &&
 842             pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
 843             SIGP_CC_ORDER_CODE_ACCEPTED)
 844                 return -EIO;
 845
 846         rc = pcpu_alloc_lowcore(pcpu, cpu);
 847         if (rc)
 848                 return rc;
 849         pcpu_prepare_secondary(pcpu, cpu);
 850         pcpu_attach_task(pcpu, tidle);
 851         pcpu_start_fn(pcpu, smp_start_secondary, NULL);
 852         /* Wait until cpu puts itself in the online & active maps */
 853         while (!cpu_online(cpu))
 854                 cpu_relax();
 855         return 0;
 856 }
 857
 858 static unsigned int setup_possible_cpus __initdata;
 859
 860 static int __init _setup_possible_cpus(char *s)
 861 {
 862         get_option(&s, &setup_possible_cpus);
 863         return 0;
 864 }
 865 early_param("possible_cpus", _setup_possible_cpus);
 866
 867 #ifdef CONFIG_HOTPLUG_CPU
 868
 869 int __cpu_disable(void)
 870 {
 871         unsigned long cregs[16];
 872
 873         /* Handle possible pending IPIs */
 874         smp_handle_ext_call();
 875         set_cpu_online(smp_processor_id(), false);
 876         /* Disable pseudo page faults on this cpu. */
 877         pfault_fini();
 878         /* Disable interrupt sources via control register. */
 879         __ctl_store(cregs, 0, 15);
 880         cregs[0]  &= ~0x0000ee70UL;     /* disable all external interrupts */
 881         cregs[6]  &= ~0xff000000UL;     /* disable all I/O interrupts */
 882         cregs[14] &= ~0x1f000000UL;     /* disable most machine checks */
 883         __ctl_load(cregs, 0, 15);
 884         clear_cpu_flag(CIF_NOHZ_DELAY);
 885         return 0;
 886 }
 887
 888 void __cpu_die(unsigned int cpu)
 889 {
 890         struct pcpu *pcpu;
 891
 892         /* Wait until target cpu is down */
 893         pcpu = pcpu_devices + cpu;
 894         while (!pcpu_stopped(pcpu))
 895                 cpu_relax();
 896         pcpu_free_lowcore(pcpu);
 897         cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
 898         cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
 899 }
 900
 901 void __noreturn cpu_die(void)
 902 {
 903         idle_task_exit();
 904         pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
 905         for (;;) ;
 906 }
 907
 908 #endif /* CONFIG_HOTPLUG_CPU */
 909
 910 void __init smp_fill_possible_mask(void)
 911 {
 912         unsigned int possible, sclp_max, cpu;
 913
 914         sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
 915         sclp_max = min(smp_max_threads, sclp_max);
 916         sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
 917         possible = setup_possible_cpus ?: nr_cpu_ids;
 918         possible = min(possible, sclp_max);
 919         for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
 920                 set_cpu_possible(cpu, true);
 921 }
 922
 923 void __init smp_prepare_cpus(unsigned int max_cpus)
 924 {
 925         /* request the 0x1201 emergency signal external interrupt */
 926         if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
 927                 panic("Couldn't request external interrupt 0x1201");
 928         /* request the 0x1202 external call external interrupt */
 929         if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
 930                 panic("Couldn't request external interrupt 0x1202");
 931 }
 932
 933 void __init smp_prepare_boot_cpu(void)
 934 {
 935         struct pcpu *pcpu = pcpu_devices;
 936
 937         WARN_ON(!cpu_present(0) || !cpu_online(0));
 938         pcpu->state = CPU_STATE_CONFIGURED;
 939         pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
 940         S390_lowcore.percpu_offset = __per_cpu_offset[0];
 941         smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
 942 }
 943
 944 void __init smp_cpus_done(unsigned int max_cpus)
 945 {
 946 }
 947
 948 void __init smp_setup_processor_id(void)
 949 {
 950         pcpu_devices[0].address = stap();
 951         S390_lowcore.cpu_nr = 0;
 952         S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
 953         S390_lowcore.spinlock_index = 0;
 954 }
 955
 956 /*
 957  * the frequency of the profiling timer can be changed
 958  * by writing a multiplier value into /proc/profile.
 959  *
 960  * usually you want to run this on all CPUs ;)
 961  */
 962 int setup_profiling_timer(unsigned int multiplier)
 963 {
 964         return 0;
 965 }
 966
 967 #ifdef CONFIG_HOTPLUG_CPU
 968 static ssize_t cpu_configure_show(struct device *dev,
 969                                   struct device_attribute *attr, char *buf)
 970 {
 971         ssize_t count;
 972
 973         mutex_lock(&smp_cpu_state_mutex);
 974         count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
 975         mutex_unlock(&smp_cpu_state_mutex);
 976         return count;
 977 }
 978
 979 static ssize_t cpu_configure_store(struct device *dev,
 980                                    struct device_attribute *attr,
 981                                    const char *buf, size_t count)
 982 {
 983         struct pcpu *pcpu;
 984         int cpu, val, rc, i;
 985         char delim;
 986
 987         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 988                 return -EINVAL;
 989         if (val != 0 && val != 1)
 990                 return -EINVAL;
 991         get_online_cpus();
 992         mutex_lock(&smp_cpu_state_mutex);
 993         rc = -EBUSY;
 994         /* disallow configuration changes of online cpus and cpu 0 */
 995         cpu = dev->id;
 996         cpu = smp_get_base_cpu(cpu);
 997         if (cpu == 0)
 998                 goto out;
 999         for (i = 0; i <= smp_cpu_mtid; i++)
1000                 if (cpu_online(cpu + i))
1001                         goto out;
1002         pcpu = pcpu_devices + cpu;
1003         rc = 0;
1004         switch (val) {
1005         case 0:
1006                 if (pcpu->state != CPU_STATE_CONFIGURED)
1007                         break;
1008                 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1009                 if (rc)
1010                         break;
1011                 for (i = 0; i <= smp_cpu_mtid; i++) {
1012                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1013                                 continue;
1014                         pcpu[i].state = CPU_STATE_STANDBY;
1015                         smp_cpu_set_polarization(cpu + i,
1016                                                  POLARIZATION_UNKNOWN);
1017                 }
1018                 topology_expect_change();
1019                 break;
1020         case 1:
1021                 if (pcpu->state != CPU_STATE_STANDBY)
1022                         break;
1023                 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1024                 if (rc)
1025                         break;
1026                 for (i = 0; i <= smp_cpu_mtid; i++) {
1027                         if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1028                                 continue;
1029                         pcpu[i].state = CPU_STATE_CONFIGURED;
1030                         smp_cpu_set_polarization(cpu + i,
1031                                                  POLARIZATION_UNKNOWN);
1032                 }
1033                 topology_expect_change();
1034                 break;
1035         default:
1036                 break;
1037         }
1038 out:
1039         mutex_unlock(&smp_cpu_state_mutex);
1040         put_online_cpus();
1041         return rc ? rc : count;
1042 }
1043 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1044 #endif /* CONFIG_HOTPLUG_CPU */
1045
1046 static ssize_t show_cpu_address(struct device *dev,
1047                                 struct device_attribute *attr, char *buf)
1048 {
1049         return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1050 }
1051 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1052
1053 static struct attribute *cpu_common_attrs[] = {
1054 #ifdef CONFIG_HOTPLUG_CPU
1055         &dev_attr_configure.attr,
1056 #endif
1057         &dev_attr_address.attr,
1058         NULL,
1059 };
1060
1061 static struct attribute_group cpu_common_attr_group = {
1062         .attrs = cpu_common_attrs,
1063 };
1064
1065 static struct attribute *cpu_online_attrs[] = {
1066         &dev_attr_idle_count.attr,
1067         &dev_attr_idle_time_us.attr,
1068         NULL,
1069 };
1070
1071 static struct attribute_group cpu_online_attr_group = {
1072         .attrs = cpu_online_attrs,
1073 };
1074
1075 static int smp_cpu_online(unsigned int cpu)
1076 {
1077         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1078
1079         return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1080 }
1081 static int smp_cpu_pre_down(unsigned int cpu)
1082 {
1083         struct device *s = &per_cpu(cpu_device, cpu)->dev;
1084
1085         sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1086         return 0;
1087 }
1088
1089 static int smp_add_present_cpu(int cpu)
1090 {
1091         struct device *s;
1092         struct cpu *c;
1093         int rc;
1094
1095         c = kzalloc(sizeof(*c), GFP_KERNEL);
1096         if (!c)
1097                 return -ENOMEM;
1098         per_cpu(cpu_device, cpu) = c;
1099         s = &c->dev;
1100         c->hotpluggable = 1;
1101         rc = register_cpu(c, cpu);
1102         if (rc)
1103                 goto out;
1104         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1105         if (rc)
1106                 goto out_cpu;
1107         rc = topology_cpu_init(c);
1108         if (rc)
1109                 goto out_topology;
1110         return 0;
1111
1112 out_topology:
1113         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1114 out_cpu:
1115 #ifdef CONFIG_HOTPLUG_CPU
1116         unregister_cpu(c);
1117 #endif
1118 out:
1119         return rc;
1120 }
1121
1122 #ifdef CONFIG_HOTPLUG_CPU
1123
1124 int __ref smp_rescan_cpus(void)
1125 {
1126         struct sclp_core_info *info;
1127         int nr;
1128
1129         info = kzalloc(sizeof(*info), GFP_KERNEL);
1130         if (!info)
1131                 return -ENOMEM;
1132         smp_get_core_info(info, 0);
1133         get_online_cpus();
1134         mutex_lock(&smp_cpu_state_mutex);
1135         nr = __smp_rescan_cpus(info, 1);
1136         mutex_unlock(&smp_cpu_state_mutex);
1137         put_online_cpus();
1138         kfree(info);
1139         if (nr)
1140                 topology_schedule_update();
1141         return 0;
1142 }
1143
1144 static ssize_t __ref rescan_store(struct device *dev,
1145                                   struct device_attribute *attr,
1146                                   const char *buf,
1147                                   size_t count)
1148 {
1149         int rc;
1150
1151         rc = smp_rescan_cpus();
1152         return rc ? rc : count;
1153 }
1154 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1155 #endif /* CONFIG_HOTPLUG_CPU */
1156
1157 static int __init s390_smp_init(void)
1158 {
1159         int cpu, rc = 0;
1160
1161 #ifdef CONFIG_HOTPLUG_CPU
1162         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1163         if (rc)
1164                 return rc;
1165 #endif
1166         for_each_present_cpu(cpu) {
1167                 rc = smp_add_present_cpu(cpu);
1168                 if (rc)
1169                         goto out;
1170         }
1171
1172         rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1173                                smp_cpu_online, smp_cpu_pre_down);
1174         rc = rc <= 0 ? rc : 0;
1175 out:
1176         return rc;
1177 }
1178 subsys_initcall(s390_smp_init);