arch/ia64/kernel/smpboot.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * SMP boot-related support
   4  *
   5  * Copyright (C) 1998-2003, 2005 Hewlett-Packard Co
   6  *      David Mosberger-Tang <davidm@hpl.hp.com>
   7  * Copyright (C) 2001, 2004-2005 Intel Corp
   8  *      Rohit Seth <rohit.seth@intel.com>
   9  *      Suresh Siddha <suresh.b.siddha@intel.com>
  10  *      Gordon Jin <gordon.jin@intel.com>
  11  *      Ashok Raj  <ashok.raj@intel.com>
  12  *
  13  * 01/05/16 Rohit Seth <rohit.seth@intel.com>   Moved SMP booting functions from smp.c to here.
  14  * 01/04/27 David Mosberger <davidm@hpl.hp.com> Added ITC synching code.
  15  * 02/07/31 David Mosberger <davidm@hpl.hp.com> Switch over to hotplug-CPU boot-sequence.
  16  *                                              smp_boot_cpus()/smp_commence() is replaced by
  17  *                                              smp_prepare_cpus()/__cpu_up()/smp_cpus_done().
  18  * 04/06/21 Ashok Raj           <ashok.raj@intel.com> Added CPU Hotplug Support
  19  * 04/12/26 Jin Gordon <gordon.jin@intel.com>
  20  * 04/12/26 Rohit Seth <rohit.seth@intel.com>
  21  *                                              Add multi-threading and multi-core detection
  22  * 05/01/30 Suresh Siddha <suresh.b.siddha@intel.com>
  23  *                                              Setup cpu_sibling_map and cpu_core_map
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/acpi.h>
  28 #include <linux/memblock.h>
  29 #include <linux/cpu.h>
  30 #include <linux/delay.h>
  31 #include <linux/init.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/irq.h>
  34 #include <linux/kernel.h>
  35 #include <linux/kernel_stat.h>
  36 #include <linux/mm.h>
  37 #include <linux/notifier.h>
  38 #include <linux/smp.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/efi.h>
  41 #include <linux/percpu.h>
  42 #include <linux/bitops.h>
  43
  44 #include <linux/atomic.h>
  45 #include <asm/cache.h>
  46 #include <asm/current.h>
  47 #include <asm/delay.h>
  48 #include <asm/io.h>
  49 #include <asm/irq.h>
  50 #include <asm/mca.h>
  51 #include <asm/page.h>
  52 #include <asm/processor.h>
  53 #include <asm/ptrace.h>
  54 #include <asm/sal.h>
  55 #include <asm/tlbflush.h>
  56 #include <asm/unistd.h>
  57
  58 #define SMP_DEBUG 0
  59
  60 #if SMP_DEBUG
  61 #define Dprintk(x...)  printk(x)
  62 #else
  63 #define Dprintk(x...)
  64 #endif
  65
  66 #ifdef CONFIG_HOTPLUG_CPU
  67 #ifdef CONFIG_PERMIT_BSP_REMOVE
  68 #define bsp_remove_ok   1
  69 #else
  70 #define bsp_remove_ok   0
  71 #endif
  72
  73 /*
  74  * Global array allocated for NR_CPUS at boot time
  75  */
  76 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
  77
  78 /*
  79  * start_ap in head.S uses this to store current booting cpu
  80  * info.
  81  */
  82 struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
  83
  84 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
  85
  86 #else
  87 #define set_brendez_area(x)
  88 #endif
  89
  90
  91 /*
  92  * ITC synchronization related stuff:
  93  */
  94 #define MASTER  (0)
  95 #define SLAVE   (SMP_CACHE_BYTES/8)
  96
  97 #define NUM_ROUNDS      64      /* magic value */
  98 #define NUM_ITERS       5       /* likewise */
  99
 100 static DEFINE_SPINLOCK(itc_sync_lock);
 101 static volatile unsigned long go[SLAVE + 1];
 102
 103 #define DEBUG_ITC_SYNC  0
 104
 105 extern void start_ap (void);
 106 extern unsigned long ia64_iobase;
 107
 108 struct task_struct *task_for_booting_cpu;
 109
 110 /*
 111  * State for each CPU
 112  */
 113 DEFINE_PER_CPU(int, cpu_state);
 114
 115 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
 116 EXPORT_SYMBOL(cpu_core_map);
 117 DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
 118 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
 119
 120 int smp_num_siblings = 1;
 121
 122 /* which logical CPU number maps to which CPU (physical APIC ID) */
 123 volatile int ia64_cpu_to_sapicid[NR_CPUS];
 124 EXPORT_SYMBOL(ia64_cpu_to_sapicid);
 125
 126 static cpumask_t cpu_callin_map;
 127
 128 struct smp_boot_data smp_boot_data __initdata;
 129
 130 unsigned long ap_wakeup_vector = -1; /* External Int use to wakeup APs */
 131
 132 char __initdata no_int_routing;
 133
 134 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
 135
 136 #ifdef CONFIG_FORCE_CPEI_RETARGET
 137 #define CPEI_OVERRIDE_DEFAULT   (1)
 138 #else
 139 #define CPEI_OVERRIDE_DEFAULT   (0)
 140 #endif
 141
 142 unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
 143
 144 static int __init
 145 cmdl_force_cpei(char *str)
 146 {
 147         int value=0;
 148
 149         get_option (&str, &value);
 150         force_cpei_retarget = value;
 151
 152         return 1;
 153 }
 154
 155 __setup("force_cpei=", cmdl_force_cpei);
 156
 157 static int __init
 158 nointroute (char *str)
 159 {
 160         no_int_routing = 1;
 161         printk ("no_int_routing on\n");
 162         return 1;
 163 }
 164
 165 __setup("nointroute", nointroute);
 166
 167 static void fix_b0_for_bsp(void)
 168 {
 169 #ifdef CONFIG_HOTPLUG_CPU
 170         int cpuid;
 171         static int fix_bsp_b0 = 1;
 172
 173         cpuid = smp_processor_id();
 174
 175         /*
 176          * Cache the b0 value on the first AP that comes up
 177          */
 178         if (!(fix_bsp_b0 && cpuid))
 179                 return;
 180
 181         sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
 182         printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
 183
 184         fix_bsp_b0 = 0;
 185 #endif
 186 }
 187
 188 void
 189 sync_master (void *arg)
 190 {
 191         unsigned long flags, i;
 192
 193         go[MASTER] = 0;
 194
 195         local_irq_save(flags);
 196         {
 197                 for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
 198                         while (!go[MASTER])
 199                                 cpu_relax();
 200                         go[MASTER] = 0;
 201                         go[SLAVE] = ia64_get_itc();
 202                 }
 203         }
 204         local_irq_restore(flags);
 205 }
 206
 207 /*
 208  * Return the number of cycles by which our itc differs from the itc on the master
 209  * (time-keeper) CPU.  A positive number indicates our itc is ahead of the master,
 210  * negative that it is behind.
 211  */
 212 static inline long
 213 get_delta (long *rt, long *master)
 214 {
 215         unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
 216         unsigned long tcenter, t0, t1, tm;
 217         long i;
 218
 219         for (i = 0; i < NUM_ITERS; ++i) {
 220                 t0 = ia64_get_itc();
 221                 go[MASTER] = 1;
 222                 while (!(tm = go[SLAVE]))
 223                         cpu_relax();
 224                 go[SLAVE] = 0;
 225                 t1 = ia64_get_itc();
 226
 227                 if (t1 - t0 < best_t1 - best_t0)
 228                         best_t0 = t0, best_t1 = t1, best_tm = tm;
 229         }
 230
 231         *rt = best_t1 - best_t0;
 232         *master = best_tm - best_t0;
 233
 234         /* average best_t0 and best_t1 without overflow: */
 235         tcenter = (best_t0/2 + best_t1/2);
 236         if (best_t0 % 2 + best_t1 % 2 == 2)
 237                 ++tcenter;
 238         return tcenter - best_tm;
 239 }
 240
 241 /*
 242  * Synchronize ar.itc of the current (slave) CPU with the ar.itc of the MASTER CPU
 243  * (normally the time-keeper CPU).  We use a closed loop to eliminate the possibility of
 244  * unaccounted-for errors (such as getting a machine check in the middle of a calibration
 245  * step).  The basic idea is for the slave to ask the master what itc value it has and to
 246  * read its own itc before and after the master responds.  Each iteration gives us three
 247  * timestamps:
 248  *
 249  *      slave           master
 250  *
 251  *      t0 ---\
 252  *             ---\
 253  *                 --->
 254  *                      tm
 255  *                 /---
 256  *             /---
 257  *      t1 <---
 258  *
 259  *
 260  * The goal is to adjust the slave's ar.itc such that tm falls exactly half-way between t0
 261  * and t1.  If we achieve this, the clocks are synchronized provided the interconnect
 262  * between the slave and the master is symmetric.  Even if the interconnect were
 263  * asymmetric, we would still know that the synchronization error is smaller than the
 264  * roundtrip latency (t0 - t1).
 265  *
 266  * When the interconnect is quiet and symmetric, this lets us synchronize the itc to
 267  * within one or two cycles.  However, we can only *guarantee* that the synchronization is
 268  * accurate to within a round-trip time, which is typically in the range of several
 269  * hundred cycles (e.g., ~500 cycles).  In practice, this means that the itc's are usually
 270  * almost perfectly synchronized, but we shouldn't assume that the accuracy is much better
 271  * than half a micro second or so.
 272  */
 273 void
 274 ia64_sync_itc (unsigned int master)
 275 {
 276         long i, delta, adj, adjust_latency = 0, done = 0;
 277         unsigned long flags, rt, master_time_stamp, bound;
 278 #if DEBUG_ITC_SYNC
 279         struct {
 280                 long rt;        /* roundtrip time */
 281                 long master;    /* master's timestamp */
 282                 long diff;      /* difference between midpoint and master's timestamp */
 283                 long lat;       /* estimate of itc adjustment latency */
 284         } t[NUM_ROUNDS];
 285 #endif
 286
 287         /*
 288          * Make sure local timer ticks are disabled while we sync.  If
 289          * they were enabled, we'd have to worry about nasty issues
 290          * like setting the ITC ahead of (or a long time before) the
 291          * next scheduled tick.
 292          */
 293         BUG_ON((ia64_get_itv() & (1 << 16)) == 0);
 294
 295         go[MASTER] = 1;
 296
 297         if (smp_call_function_single(master, sync_master, NULL, 0) < 0) {
 298                 printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
 299                 return;
 300         }
 301
 302         while (go[MASTER])
 303                 cpu_relax();    /* wait for master to be ready */
 304
 305         spin_lock_irqsave(&itc_sync_lock, flags);
 306         {
 307                 for (i = 0; i < NUM_ROUNDS; ++i) {
 308                         delta = get_delta(&rt, &master_time_stamp);
 309                         if (delta == 0) {
 310                                 done = 1;       /* let's lock on to this... */
 311                                 bound = rt;
 312                         }
 313
 314                         if (!done) {
 315                                 if (i > 0) {
 316                                         adjust_latency += -delta;
 317                                         adj = -delta + adjust_latency/4;
 318                                 } else
 319                                         adj = -delta;
 320
 321                                 ia64_set_itc(ia64_get_itc() + adj);
 322                         }
 323 #if DEBUG_ITC_SYNC
 324                         t[i].rt = rt;
 325                         t[i].master = master_time_stamp;
 326                         t[i].diff = delta;
 327                         t[i].lat = adjust_latency/4;
 328 #endif
 329                 }
 330         }
 331         spin_unlock_irqrestore(&itc_sync_lock, flags);
 332
 333 #if DEBUG_ITC_SYNC
 334         for (i = 0; i < NUM_ROUNDS; ++i)
 335                 printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
 336                        t[i].rt, t[i].master, t[i].diff, t[i].lat);
 337 #endif
 338
 339         printk(KERN_INFO "CPU %d: synchronized ITC with CPU %u (last diff %ld cycles, "
 340                "maxerr %lu cycles)\n", smp_processor_id(), master, delta, rt);
 341 }
 342
 343 /*
 344  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
 345  */
 346 static inline void smp_setup_percpu_timer(void)
 347 {
 348 }
 349
 350 static void
 351 smp_callin (void)
 352 {
 353         int cpuid, phys_id, itc_master;
 354         struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
 355         extern void ia64_init_itm(void);
 356         extern volatile int time_keeper_id;
 357
 358         cpuid = smp_processor_id();
 359         phys_id = hard_smp_processor_id();
 360         itc_master = time_keeper_id;
 361
 362         if (cpu_online(cpuid)) {
 363                 printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
 364                        phys_id, cpuid);
 365                 BUG();
 366         }
 367
 368         fix_b0_for_bsp();
 369
 370         /*
 371          * numa_node_id() works after this.
 372          */
 373         set_numa_node(cpu_to_node_map[cpuid]);
 374         set_numa_mem(local_memory_node(cpu_to_node_map[cpuid]));
 375
 376         spin_lock(&vector_lock);
 377         /* Setup the per cpu irq handling data structures */
 378         __setup_vector_irq(cpuid);
 379         notify_cpu_starting(cpuid);
 380         set_cpu_online(cpuid, true);
 381         per_cpu(cpu_state, cpuid) = CPU_ONLINE;
 382         spin_unlock(&vector_lock);
 383
 384         smp_setup_percpu_timer();
 385
 386         ia64_mca_cmc_vector_setup();    /* Setup vector on AP */
 387
 388         local_irq_enable();
 389
 390         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
 391                 /*
 392                  * Synchronize the ITC with the BP.  Need to do this after irqs are
 393                  * enabled because ia64_sync_itc() calls smp_call_function_single(), which
 394                  * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
 395                  * local_bh_enable(), which bugs out if irqs are not enabled...
 396                  */
 397                 Dprintk("Going to syncup ITC with ITC Master.\n");
 398                 ia64_sync_itc(itc_master);
 399         }
 400
 401         /*
 402          * Get our bogomips.
 403          */
 404         ia64_init_itm();
 405
 406         /*
 407          * Delay calibration can be skipped if new processor is identical to the
 408          * previous processor.
 409          */
 410         last_cpuinfo = cpu_data(cpuid - 1);
 411         this_cpuinfo = local_cpu_data;
 412         if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
 413             last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
 414             last_cpuinfo->features != this_cpuinfo->features ||
 415             last_cpuinfo->revision != this_cpuinfo->revision ||
 416             last_cpuinfo->family != this_cpuinfo->family ||
 417             last_cpuinfo->archrev != this_cpuinfo->archrev ||
 418             last_cpuinfo->model != this_cpuinfo->model)
 419                 calibrate_delay();
 420         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 421
 422         /*
 423          * Allow the master to continue.
 424          */
 425         cpumask_set_cpu(cpuid, &cpu_callin_map);
 426         Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
 427 }
 428
 429
 430 /*
 431  * Activate a secondary processor.  head.S calls this.
 432  */
 433 int
 434 start_secondary (void *unused)
 435 {
 436         /* Early console may use I/O ports */
 437         ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
 438 #ifndef CONFIG_PRINTK_TIME
 439         Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
 440 #endif
 441         efi_map_pal_code();
 442         cpu_init();
 443         preempt_disable();
 444         smp_callin();
 445
 446         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 447         return 0;
 448 }
 449
 450 static int
 451 do_boot_cpu (int sapicid, int cpu, struct task_struct *idle)
 452 {
 453         int timeout;
 454
 455         task_for_booting_cpu = idle;
 456         Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
 457
 458         set_brendez_area(cpu);
 459         ia64_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
 460
 461         /*
 462          * Wait 10s total for the AP to start
 463          */
 464         Dprintk("Waiting on callin_map ...");
 465         for (timeout = 0; timeout < 100000; timeout++) {
 466                 if (cpumask_test_cpu(cpu, &cpu_callin_map))
 467                         break;  /* It has booted */
 468                 barrier(); /* Make sure we re-read cpu_callin_map */
 469                 udelay(100);
 470         }
 471         Dprintk("\n");
 472
 473         if (!cpumask_test_cpu(cpu, &cpu_callin_map)) {
 474                 printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
 475                 ia64_cpu_to_sapicid[cpu] = -1;
 476                 set_cpu_online(cpu, false);  /* was set in smp_callin() */
 477                 return -EINVAL;
 478         }
 479         return 0;
 480 }
 481
 482 static int __init
 483 decay (char *str)
 484 {
 485         int ticks;
 486         get_option (&str, &ticks);
 487         return 1;
 488 }
 489
 490 __setup("decay=", decay);
 491
 492 /*
 493  * Initialize the logical CPU number to SAPICID mapping
 494  */
 495 void __init
 496 smp_build_cpu_map (void)
 497 {
 498         int sapicid, cpu, i;
 499         int boot_cpu_id = hard_smp_processor_id();
 500
 501         for (cpu = 0; cpu < NR_CPUS; cpu++) {
 502                 ia64_cpu_to_sapicid[cpu] = -1;
 503         }
 504
 505         ia64_cpu_to_sapicid[0] = boot_cpu_id;
 506         init_cpu_present(cpumask_of(0));
 507         set_cpu_possible(0, true);
 508         for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
 509                 sapicid = smp_boot_data.cpu_phys_id[i];
 510                 if (sapicid == boot_cpu_id)
 511                         continue;
 512                 set_cpu_present(cpu, true);
 513                 set_cpu_possible(cpu, true);
 514                 ia64_cpu_to_sapicid[cpu] = sapicid;
 515                 cpu++;
 516         }
 517 }
 518
 519 /*
 520  * Cycle through the APs sending Wakeup IPIs to boot each.
 521  */
 522 void __init
 523 smp_prepare_cpus (unsigned int max_cpus)
 524 {
 525         int boot_cpu_id = hard_smp_processor_id();
 526
 527         /*
 528          * Initialize the per-CPU profiling counter/multiplier
 529          */
 530
 531         smp_setup_percpu_timer();
 532
 533         cpumask_set_cpu(0, &cpu_callin_map);
 534
 535         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 536         ia64_cpu_to_sapicid[0] = boot_cpu_id;
 537
 538         printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
 539
 540         current_thread_info()->cpu = 0;
 541
 542         /*
 543          * If SMP should be disabled, then really disable it!
 544          */
 545         if (!max_cpus) {
 546                 printk(KERN_INFO "SMP mode deactivated.\n");
 547                 init_cpu_online(cpumask_of(0));
 548                 init_cpu_present(cpumask_of(0));
 549                 init_cpu_possible(cpumask_of(0));
 550                 return;
 551         }
 552 }
 553
 554 void smp_prepare_boot_cpu(void)
 555 {
 556         set_cpu_online(smp_processor_id(), true);
 557         cpumask_set_cpu(smp_processor_id(), &cpu_callin_map);
 558         set_numa_node(cpu_to_node_map[smp_processor_id()]);
 559         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
 560 }
 561
 562 #ifdef CONFIG_HOTPLUG_CPU
 563 static inline void
 564 clear_cpu_sibling_map(int cpu)
 565 {
 566         int i;
 567
 568         for_each_cpu(i, &per_cpu(cpu_sibling_map, cpu))
 569                 cpumask_clear_cpu(cpu, &per_cpu(cpu_sibling_map, i));
 570         for_each_cpu(i, &cpu_core_map[cpu])
 571                 cpumask_clear_cpu(cpu, &cpu_core_map[i]);
 572
 573         per_cpu(cpu_sibling_map, cpu) = cpu_core_map[cpu] = CPU_MASK_NONE;
 574 }
 575
 576 static void
 577 remove_siblinginfo(int cpu)
 578 {
 579         int last = 0;
 580
 581         if (cpu_data(cpu)->threads_per_core == 1 &&
 582             cpu_data(cpu)->cores_per_socket == 1) {
 583                 cpumask_clear_cpu(cpu, &cpu_core_map[cpu]);
 584                 cpumask_clear_cpu(cpu, &per_cpu(cpu_sibling_map, cpu));
 585                 return;
 586         }
 587
 588         last = (cpumask_weight(&cpu_core_map[cpu]) == 1 ? 1 : 0);
 589
 590         /* remove it from all sibling map's */
 591         clear_cpu_sibling_map(cpu);
 592 }
 593
 594 extern void fixup_irqs(void);
 595
 596 int migrate_platform_irqs(unsigned int cpu)
 597 {
 598         int new_cpei_cpu;
 599         struct irq_data *data = NULL;
 600         const struct cpumask *mask;
 601         int             retval = 0;
 602
 603         /*
 604          * dont permit CPEI target to removed.
 605          */
 606         if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
 607                 printk ("CPU (%d) is CPEI Target\n", cpu);
 608                 if (can_cpei_retarget()) {
 609                         /*
 610                          * Now re-target the CPEI to a different processor
 611                          */
 612                         new_cpei_cpu = cpumask_any(cpu_online_mask);
 613                         mask = cpumask_of(new_cpei_cpu);
 614                         set_cpei_target_cpu(new_cpei_cpu);
 615                         data = irq_get_irq_data(ia64_cpe_irq);
 616                         /*
 617                          * Switch for now, immediately, we need to do fake intr
 618                          * as other interrupts, but need to study CPEI behaviour with
 619                          * polling before making changes.
 620                          */
 621                         if (data && data->chip) {
 622                                 data->chip->irq_disable(data);
 623                                 data->chip->irq_set_affinity(data, mask, false);
 624                                 data->chip->irq_enable(data);
 625                                 printk ("Re-targeting CPEI to cpu %d\n", new_cpei_cpu);
 626                         }
 627                 }
 628                 if (!data) {
 629                         printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
 630                         retval = -EBUSY;
 631                 }
 632         }
 633         return retval;
 634 }
 635
 636 /* must be called with cpucontrol mutex held */
 637 int __cpu_disable(void)
 638 {
 639         int cpu = smp_processor_id();
 640
 641         /*
 642          * dont permit boot processor for now
 643          */
 644         if (cpu == 0 && !bsp_remove_ok) {
 645                 printk ("Your platform does not support removal of BSP\n");
 646                 return (-EBUSY);
 647         }
 648
 649         set_cpu_online(cpu, false);
 650
 651         if (migrate_platform_irqs(cpu)) {
 652                 set_cpu_online(cpu, true);
 653                 return -EBUSY;
 654         }
 655
 656         remove_siblinginfo(cpu);
 657         fixup_irqs();
 658         local_flush_tlb_all();
 659         cpumask_clear_cpu(cpu, &cpu_callin_map);
 660         return 0;
 661 }
 662
 663 void __cpu_die(unsigned int cpu)
 664 {
 665         unsigned int i;
 666
 667         for (i = 0; i < 100; i++) {
 668                 /* They ack this in play_dead by setting CPU_DEAD */
 669                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 670                 {
 671                         printk ("CPU %d is now offline\n", cpu);
 672                         return;
 673                 }
 674                 msleep(100);
 675         }
 676         printk(KERN_ERR "CPU %u didn't die...\n", cpu);
 677 }
 678 #endif /* CONFIG_HOTPLUG_CPU */
 679
 680 void
 681 smp_cpus_done (unsigned int dummy)
 682 {
 683         int cpu;
 684         unsigned long bogosum = 0;
 685
 686         /*
 687          * Allow the user to impress friends.
 688          */
 689
 690         for_each_online_cpu(cpu) {
 691                 bogosum += cpu_data(cpu)->loops_per_jiffy;
 692         }
 693
 694         printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
 695                (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
 696 }
 697
 698 static inline void set_cpu_sibling_map(int cpu)
 699 {
 700         int i;
 701
 702         for_each_online_cpu(i) {
 703                 if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
 704                         cpumask_set_cpu(i, &cpu_core_map[cpu]);
 705                         cpumask_set_cpu(cpu, &cpu_core_map[i]);
 706                         if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
 707                                 cpumask_set_cpu(i,
 708                                                 &per_cpu(cpu_sibling_map, cpu));
 709                                 cpumask_set_cpu(cpu,
 710                                                 &per_cpu(cpu_sibling_map, i));
 711                         }
 712                 }
 713         }
 714 }
 715
 716 int
 717 __cpu_up(unsigned int cpu, struct task_struct *tidle)
 718 {
 719         int ret;
 720         int sapicid;
 721
 722         sapicid = ia64_cpu_to_sapicid[cpu];
 723         if (sapicid == -1)
 724                 return -EINVAL;
 725
 726         /*
 727          * Already booted cpu? not valid anymore since we dont
 728          * do idle loop tightspin anymore.
 729          */
 730         if (cpumask_test_cpu(cpu, &cpu_callin_map))
 731                 return -EINVAL;
 732
 733         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 734         /* Processor goes to start_secondary(), sets online flag */
 735         ret = do_boot_cpu(sapicid, cpu, tidle);
 736         if (ret < 0)
 737                 return ret;
 738
 739         if (cpu_data(cpu)->threads_per_core == 1 &&
 740             cpu_data(cpu)->cores_per_socket == 1) {
 741                 cpumask_set_cpu(cpu, &per_cpu(cpu_sibling_map, cpu));
 742                 cpumask_set_cpu(cpu, &cpu_core_map[cpu]);
 743                 return 0;
 744         }
 745
 746         set_cpu_sibling_map(cpu);
 747
 748         return 0;
 749 }
 750
 751 /*
 752  * Assume that CPUs have been discovered by some platform-dependent interface.  For
 753  * SoftSDV/Lion, that would be ACPI.
 754  *
 755  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
 756  */
 757 void __init
 758 init_smp_config(void)
 759 {
 760         struct fptr {
 761                 unsigned long fp;
 762                 unsigned long gp;
 763         } *ap_startup;
 764         long sal_ret;
 765
 766         /* Tell SAL where to drop the APs.  */
 767         ap_startup = (struct fptr *) start_ap;
 768         sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
 769                                        ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
 770         if (sal_ret < 0)
 771                 printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
 772                        ia64_sal_strerror(sal_ret));
 773 }
 774
 775 /*
 776  * identify_siblings(cpu) gets called from identify_cpu. This populates the
 777  * information related to logical execution units in per_cpu_data structure.
 778  */
 779 void identify_siblings(struct cpuinfo_ia64 *c)
 780 {
 781         long status;
 782         u16 pltid;
 783         pal_logical_to_physical_t info;
 784
 785         status = ia64_pal_logical_to_phys(-1, &info);
 786         if (status != PAL_STATUS_SUCCESS) {
 787                 if (status != PAL_STATUS_UNIMPLEMENTED) {
 788                         printk(KERN_ERR
 789                                 "ia64_pal_logical_to_phys failed with %ld\n",
 790                                 status);
 791                         return;
 792                 }
 793
 794                 info.overview_ppid = 0;
 795                 info.overview_cpp  = 1;
 796                 info.overview_tpc  = 1;
 797         }
 798
 799         status = ia64_sal_physical_id_info(&pltid);
 800         if (status != PAL_STATUS_SUCCESS) {
 801                 if (status != PAL_STATUS_UNIMPLEMENTED)
 802                         printk(KERN_ERR
 803                                 "ia64_sal_pltid failed with %ld\n",
 804                                 status);
 805                 return;
 806         }
 807
 808         c->socket_id =  (pltid << 8) | info.overview_ppid;
 809
 810         if (info.overview_cpp == 1 && info.overview_tpc == 1)
 811                 return;
 812
 813         c->cores_per_socket = info.overview_cpp;
 814         c->threads_per_core = info.overview_tpc;
 815         c->num_log = info.overview_num_log;
 816
 817         c->core_id = info.log1_cid;
 818         c->thread_id = info.log1_tid;
 819 }
 820
 821 /*
 822  * returns non zero, if multi-threading is enabled
 823  * on at least one physical package. Due to hotplug cpu
 824  * and (maxcpus=), all threads may not necessarily be enabled
 825  * even though the processor supports multi-threading.
 826  */
 827 int is_multithreading_enabled(void)
 828 {
 829         int i, j;
 830
 831         for_each_present_cpu(i) {
 832                 for_each_present_cpu(j) {
 833                         if (j == i)
 834                                 continue;
 835                         if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
 836                                 if (cpu_data(j)->core_id == cpu_data(i)->core_id)
 837                                         return 1;
 838                         }
 839                 }
 840         }
 841         return 0;
 842 }
 843 EXPORT_SYMBOL_GPL(is_multithreading_enabled);