arch/ia64/kernel/smpboot.c

   1 /*
   2  * SMP boot-related support
   3  *
   4  * Copyright (C) 1998-2003, 2005 Hewlett-Packard Co
   5  *      David Mosberger-Tang <[email protected]>
   6  * Copyright (C) 2001, 2004-2005 Intel Corp
   7  *      Rohit Seth <[email protected]>
   8  *      Suresh Siddha <[email protected]>
   9  *      Gordon Jin <[email protected]>
  10  *      Ashok Raj  <[email protected]>
  11  *
  12  * 01/05/16 Rohit Seth <[email protected]>   Moved SMP booting functions from smp.c to here.
  13  * 01/04/27 David Mosberger <[email protected]> Added ITC synching code.
  14  * 02/07/31 David Mosberger <[email protected]> Switch over to hotplug-CPU boot-sequence.
  15  *                                              smp_boot_cpus()/smp_commence() is replaced by
  16  *                                              smp_prepare_cpus()/__cpu_up()/smp_cpus_done().
  17  * 04/06/21 Ashok Raj           <[email protected]> Added CPU Hotplug Support
  18  * 04/12/26 Jin Gordon <[email protected]>
  19  * 04/12/26 Rohit Seth <[email protected]>
  20  *                                              Add multi-threading and multi-core detection
  21  * 05/01/30 Suresh Siddha <[email protected]>
  22  *                                              Setup cpu_sibling_map and cpu_core_map
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/acpi.h>
  27 #include <linux/bootmem.h>
  28 #include <linux/cpu.h>
  29 #include <linux/delay.h>
  30 #include <linux/init.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/irq.h>
  33 #include <linux/kernel.h>
  34 #include <linux/kernel_stat.h>
  35 #include <linux/mm.h>
  36 #include <linux/notifier.h>
  37 #include <linux/smp.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/efi.h>
  40 #include <linux/percpu.h>
  41 #include <linux/bitops.h>
  42
  43 #include <linux/atomic.h>
  44 #include <asm/cache.h>
  45 #include <asm/current.h>
  46 #include <asm/delay.h>
  47 #include <asm/io.h>
  48 #include <asm/irq.h>
  49 #include <asm/machvec.h>
  50 #include <asm/mca.h>
  51 #include <asm/page.h>
  52 #include <asm/paravirt.h>
  53 #include <asm/pgalloc.h>
  54 #include <asm/pgtable.h>
  55 #include <asm/processor.h>
  56 #include <asm/ptrace.h>
  57 #include <asm/sal.h>
  58 #include <asm/tlbflush.h>
  59 #include <asm/unistd.h>
  60 #include <asm/sn/arch.h>
  61
  62 #define SMP_DEBUG 0
  63
  64 #if SMP_DEBUG
  65 #define Dprintk(x...)  printk(x)
  66 #else
  67 #define Dprintk(x...)
  68 #endif
  69
  70 #ifdef CONFIG_HOTPLUG_CPU
  71 #ifdef CONFIG_PERMIT_BSP_REMOVE
  72 #define bsp_remove_ok   1
  73 #else
  74 #define bsp_remove_ok   0
  75 #endif
  76
  77 /*
  78  * Global array allocated for NR_CPUS at boot time
  79  */
  80 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
  81
  82 /*
  83  * start_ap in head.S uses this to store current booting cpu
  84  * info.
  85  */
  86 struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
  87
  88 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
  89
  90 #else
  91 #define set_brendez_area(x)
  92 #endif
  93
  94
  95 /*
  96  * ITC synchronization related stuff:
  97  */
  98 #define MASTER  (0)
  99 #define SLAVE   (SMP_CACHE_BYTES/8)
 100
 101 #define NUM_ROUNDS      64      /* magic value */
 102 #define NUM_ITERS       5       /* likewise */
 103
 104 static DEFINE_SPINLOCK(itc_sync_lock);
 105 static volatile unsigned long go[SLAVE + 1];
 106
 107 #define DEBUG_ITC_SYNC  0
 108
 109 extern void start_ap (void);
 110 extern unsigned long ia64_iobase;
 111
 112 struct task_struct *task_for_booting_cpu;
 113
 114 /*
 115  * State for each CPU
 116  */
 117 DEFINE_PER_CPU(int, cpu_state);
 118
 119 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
 120 EXPORT_SYMBOL(cpu_core_map);
 121 DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
 122 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
 123
 124 int smp_num_siblings = 1;
 125
 126 /* which logical CPU number maps to which CPU (physical APIC ID) */
 127 volatile int ia64_cpu_to_sapicid[NR_CPUS];
 128 EXPORT_SYMBOL(ia64_cpu_to_sapicid);
 129
 130 static volatile cpumask_t cpu_callin_map;
 131
 132 struct smp_boot_data smp_boot_data __initdata;
 133
 134 unsigned long ap_wakeup_vector = -1; /* External Int use to wakeup APs */
 135
 136 char __initdata no_int_routing;
 137
 138 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
 139
 140 #ifdef CONFIG_FORCE_CPEI_RETARGET
 141 #define CPEI_OVERRIDE_DEFAULT   (1)
 142 #else
 143 #define CPEI_OVERRIDE_DEFAULT   (0)
 144 #endif
 145
 146 unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
 147
 148 static int __init
 149 cmdl_force_cpei(char *str)
 150 {
 151         int value=0;
 152
 153         get_option (&str, &value);
 154         force_cpei_retarget = value;
 155
 156         return 1;
 157 }
 158
 159 __setup("force_cpei=", cmdl_force_cpei);
 160
 161 static int __init
 162 nointroute (char *str)
 163 {
 164         no_int_routing = 1;
 165         printk ("no_int_routing on\n");
 166         return 1;
 167 }
 168
 169 __setup("nointroute", nointroute);
 170
 171 static void fix_b0_for_bsp(void)
 172 {
 173 #ifdef CONFIG_HOTPLUG_CPU
 174         int cpuid;
 175         static int fix_bsp_b0 = 1;
 176
 177         cpuid = smp_processor_id();
 178
 179         /*
 180          * Cache the b0 value on the first AP that comes up
 181          */
 182         if (!(fix_bsp_b0 && cpuid))
 183                 return;
 184
 185         sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
 186         printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
 187
 188         fix_bsp_b0 = 0;
 189 #endif
 190 }
 191
 192 void
 193 sync_master (void *arg)
 194 {
 195         unsigned long flags, i;
 196
 197         go[MASTER] = 0;
 198
 199         local_irq_save(flags);
 200         {
 201                 for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
 202                         while (!go[MASTER])
 203                                 cpu_relax();
 204                         go[MASTER] = 0;
 205                         go[SLAVE] = ia64_get_itc();
 206                 }
 207         }
 208         local_irq_restore(flags);
 209 }
 210
 211 /*
 212  * Return the number of cycles by which our itc differs from the itc on the master
 213  * (time-keeper) CPU.  A positive number indicates our itc is ahead of the master,
 214  * negative that it is behind.
 215  */
 216 static inline long
 217 get_delta (long *rt, long *master)
 218 {
 219         unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
 220         unsigned long tcenter, t0, t1, tm;
 221         long i;
 222
 223         for (i = 0; i < NUM_ITERS; ++i) {
 224                 t0 = ia64_get_itc();
 225                 go[MASTER] = 1;
 226                 while (!(tm = go[SLAVE]))
 227                         cpu_relax();
 228                 go[SLAVE] = 0;
 229                 t1 = ia64_get_itc();
 230
 231                 if (t1 - t0 < best_t1 - best_t0)
 232                         best_t0 = t0, best_t1 = t1, best_tm = tm;
 233         }
 234
 235         *rt = best_t1 - best_t0;
 236         *master = best_tm - best_t0;
 237
 238         /* average best_t0 and best_t1 without overflow: */
 239         tcenter = (best_t0/2 + best_t1/2);
 240         if (best_t0 % 2 + best_t1 % 2 == 2)
 241                 ++tcenter;
 242         return tcenter - best_tm;
 243 }
 244
 245 /*
 246  * Synchronize ar.itc of the current (slave) CPU with the ar.itc of the MASTER CPU
 247  * (normally the time-keeper CPU).  We use a closed loop to eliminate the possibility of
 248  * unaccounted-for errors (such as getting a machine check in the middle of a calibration
 249  * step).  The basic idea is for the slave to ask the master what itc value it has and to
 250  * read its own itc before and after the master responds.  Each iteration gives us three
 251  * timestamps:
 252  *
 253  *      slave           master
 254  *
 255  *      t0 ---\
 256  *             ---\
 257  *                 --->
 258  *                      tm
 259  *                 /---
 260  *             /---
 261  *      t1 <---
 262  *
 263  *
 264  * The goal is to adjust the slave's ar.itc such that tm falls exactly half-way between t0
 265  * and t1.  If we achieve this, the clocks are synchronized provided the interconnect
 266  * between the slave and the master is symmetric.  Even if the interconnect were
 267  * asymmetric, we would still know that the synchronization error is smaller than the
 268  * roundtrip latency (t0 - t1).
 269  *
 270  * When the interconnect is quiet and symmetric, this lets us synchronize the itc to
 271  * within one or two cycles.  However, we can only *guarantee* that the synchronization is
 272  * accurate to within a round-trip time, which is typically in the range of several
 273  * hundred cycles (e.g., ~500 cycles).  In practice, this means that the itc's are usually
 274  * almost perfectly synchronized, but we shouldn't assume that the accuracy is much better
 275  * than half a micro second or so.
 276  */
 277 void
 278 ia64_sync_itc (unsigned int master)
 279 {
 280         long i, delta, adj, adjust_latency = 0, done = 0;
 281         unsigned long flags, rt, master_time_stamp, bound;
 282 #if DEBUG_ITC_SYNC
 283         struct {
 284                 long rt;        /* roundtrip time */
 285                 long master;    /* master's timestamp */
 286                 long diff;      /* difference between midpoint and master's timestamp */
 287                 long lat;       /* estimate of itc adjustment latency */
 288         } t[NUM_ROUNDS];
 289 #endif
 290
 291         /*
 292          * Make sure local timer ticks are disabled while we sync.  If
 293          * they were enabled, we'd have to worry about nasty issues
 294          * like setting the ITC ahead of (or a long time before) the
 295          * next scheduled tick.
 296          */
 297         BUG_ON((ia64_get_itv() & (1 << 16)) == 0);
 298
 299         go[MASTER] = 1;
 300
 301         if (smp_call_function_single(master, sync_master, NULL, 0) < 0) {
 302                 printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
 303                 return;
 304         }
 305
 306         while (go[MASTER])
 307                 cpu_relax();    /* wait for master to be ready */
 308
 309         spin_lock_irqsave(&itc_sync_lock, flags);
 310         {
 311                 for (i = 0; i < NUM_ROUNDS; ++i) {
 312                         delta = get_delta(&rt, &master_time_stamp);
 313                         if (delta == 0) {
 314                                 done = 1;       /* let's lock on to this... */
 315                                 bound = rt;
 316                         }
 317
 318                         if (!done) {
 319                                 if (i > 0) {
 320                                         adjust_latency += -delta;
 321                                         adj = -delta + adjust_latency/4;
 322                                 } else
 323                                         adj = -delta;
 324
 325                                 ia64_set_itc(ia64_get_itc() + adj);
 326                         }
 327 #if DEBUG_ITC_SYNC
 328                         t[i].rt = rt;
 329                         t[i].master = master_time_stamp;
 330                         t[i].diff = delta;
 331                         t[i].lat = adjust_latency/4;
 332 #endif
 333                 }
 334         }
 335         spin_unlock_irqrestore(&itc_sync_lock, flags);
 336
 337 #if DEBUG_ITC_SYNC
 338         for (i = 0; i < NUM_ROUNDS; ++i)
 339                 printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
 340                        t[i].rt, t[i].master, t[i].diff, t[i].lat);
 341 #endif
 342
 343         printk(KERN_INFO "CPU %d: synchronized ITC with CPU %u (last diff %ld cycles, "
 344                "maxerr %lu cycles)\n", smp_processor_id(), master, delta, rt);
 345 }
 346
 347 /*
 348  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
 349  */
 350 static inline void smp_setup_percpu_timer(void)
 351 {
 352 }
 353
 354 static void
 355 smp_callin (void)
 356 {
 357         int cpuid, phys_id, itc_master;
 358         struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
 359         extern void ia64_init_itm(void);
 360         extern volatile int time_keeper_id;
 361
 362 #ifdef CONFIG_PERFMON
 363         extern void pfm_init_percpu(void);
 364 #endif
 365
 366         cpuid = smp_processor_id();
 367         phys_id = hard_smp_processor_id();
 368         itc_master = time_keeper_id;
 369
 370         if (cpu_online(cpuid)) {
 371                 printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
 372                        phys_id, cpuid);
 373                 BUG();
 374         }
 375
 376         fix_b0_for_bsp();
 377
 378         /*
 379          * numa_node_id() works after this.
 380          */
 381         set_numa_node(cpu_to_node_map[cpuid]);
 382         set_numa_mem(local_memory_node(cpu_to_node_map[cpuid]));
 383
 384         spin_lock(&vector_lock);
 385         /* Setup the per cpu irq handling data structures */
 386         __setup_vector_irq(cpuid);
 387         notify_cpu_starting(cpuid);
 388         set_cpu_online(cpuid, true);
 389         per_cpu(cpu_state, cpuid) = CPU_ONLINE;
 390         spin_unlock(&vector_lock);
 391
 392         smp_setup_percpu_timer();
 393
 394         ia64_mca_cmc_vector_setup();    /* Setup vector on AP */
 395
 396 #ifdef CONFIG_PERFMON
 397         pfm_init_percpu();
 398 #endif
 399
 400         local_irq_enable();
 401
 402         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
 403                 /*
 404                  * Synchronize the ITC with the BP.  Need to do this after irqs are
 405                  * enabled because ia64_sync_itc() calls smp_call_function_single(), which
 406                  * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
 407                  * local_bh_enable(), which bugs out if irqs are not enabled...
 408                  */
 409                 Dprintk("Going to syncup ITC with ITC Master.\n");
 410                 ia64_sync_itc(itc_master);
 411         }
 412
 413         /*
 414          * Get our bogomips.
 415          */
 416         ia64_init_itm();
 417
 418         /*
 419          * Delay calibration can be skipped if new processor is identical to the
 420          * previous processor.
 421          */
 422         last_cpuinfo = cpu_data(cpuid - 1);
 423         this_cpuinfo = local_cpu_data;
 424         if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
 425             last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
 426             last_cpuinfo->features != this_cpuinfo->features ||
 427             last_cpuinfo->revision != this_cpuinfo->revision ||
 428             last_cpuinfo->family != this_cpuinfo->family ||
 429             last_cpuinfo->archrev != this_cpuinfo->archrev ||
 430             last_cpuinfo->model != this_cpuinfo->model)
 431                 calibrate_delay();
 432         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 433
 434         /*
 435          * Allow the master to continue.
 436          */
 437         cpu_set(cpuid, cpu_callin_map);
 438         Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
 439 }
 440
 441
 442 /*
 443  * Activate a secondary processor.  head.S calls this.
 444  */
 445 int
 446 start_secondary (void *unused)
 447 {
 448         /* Early console may use I/O ports */
 449         ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
 450 #ifndef CONFIG_PRINTK_TIME
 451         Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
 452 #endif
 453         efi_map_pal_code();
 454         cpu_init();
 455         preempt_disable();
 456         smp_callin();
 457
 458         cpu_startup_entry(CPUHP_ONLINE);
 459         return 0;
 460 }
 461
 462 static int
 463 do_boot_cpu (int sapicid, int cpu, struct task_struct *idle)
 464 {
 465         int timeout;
 466
 467         task_for_booting_cpu = idle;
 468         Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
 469
 470         set_brendez_area(cpu);
 471         platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
 472
 473         /*
 474          * Wait 10s total for the AP to start
 475          */
 476         Dprintk("Waiting on callin_map ...");
 477         for (timeout = 0; timeout < 100000; timeout++) {
 478                 if (cpu_isset(cpu, cpu_callin_map))
 479                         break;  /* It has booted */
 480                 udelay(100);
 481         }
 482         Dprintk("\n");
 483
 484         if (!cpu_isset(cpu, cpu_callin_map)) {
 485                 printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
 486                 ia64_cpu_to_sapicid[cpu] = -1;
 487                 set_cpu_online(cpu, false);  /* was set in smp_callin() */
 488                 return -EINVAL;
 489         }
 490         return 0;
 491 }
 492
 493 static int __init
 494 decay (char *str)
 495 {
 496         int ticks;
 497         get_option (&str, &ticks);
 498         return 1;
 499 }
 500
 501 __setup("decay=", decay);
 502
 503 /*
 504  * Initialize the logical CPU number to SAPICID mapping
 505  */
 506 void __init
 507 smp_build_cpu_map (void)
 508 {
 509         int sapicid, cpu, i;
 510         int boot_cpu_id = hard_smp_processor_id();
 511
 512         for (cpu = 0; cpu < NR_CPUS; cpu++) {
 513                 ia64_cpu_to_sapicid[cpu] = -1;
 514         }
 515
 516         ia64_cpu_to_sapicid[0] = boot_cpu_id;
 517         init_cpu_present(cpumask_of(0));
 518         set_cpu_possible(0, true);
 519         for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
 520                 sapicid = smp_boot_data.cpu_phys_id[i];
 521                 if (sapicid == boot_cpu_id)
 522                         continue;
 523                 set_cpu_present(cpu, true);
 524                 set_cpu_possible(cpu, true);
 525                 ia64_cpu_to_sapicid[cpu] = sapicid;
 526                 cpu++;
 527         }
 528 }
 529
 530 /*
 531  * Cycle through the APs sending Wakeup IPIs to boot each.
 532  */
 533 void __init
 534 smp_prepare_cpus (unsigned int max_cpus)
 535 {
 536         int boot_cpu_id = hard_smp_processor_id();
 537
 538         /*
 539          * Initialize the per-CPU profiling counter/multiplier
 540          */
 541
 542         smp_setup_percpu_timer();
 543
 544         cpu_set(0, cpu_callin_map);
 545
 546         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 547         ia64_cpu_to_sapicid[0] = boot_cpu_id;
 548
 549         printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
 550
 551         current_thread_info()->cpu = 0;
 552
 553         /*
 554          * If SMP should be disabled, then really disable it!
 555          */
 556         if (!max_cpus) {
 557                 printk(KERN_INFO "SMP mode deactivated.\n");
 558                 init_cpu_online(cpumask_of(0));
 559                 init_cpu_present(cpumask_of(0));
 560                 init_cpu_possible(cpumask_of(0));
 561                 return;
 562         }
 563 }
 564
 565 void smp_prepare_boot_cpu(void)
 566 {
 567         set_cpu_online(smp_processor_id(), true);
 568         cpu_set(smp_processor_id(), cpu_callin_map);
 569         set_numa_node(cpu_to_node_map[smp_processor_id()]);
 570         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
 571         paravirt_post_smp_prepare_boot_cpu();
 572 }
 573
 574 #ifdef CONFIG_HOTPLUG_CPU
 575 static inline void
 576 clear_cpu_sibling_map(int cpu)
 577 {
 578         int i;
 579
 580         for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu))
 581                 cpu_clear(cpu, per_cpu(cpu_sibling_map, i));
 582         for_each_cpu_mask(i, cpu_core_map[cpu])
 583                 cpu_clear(cpu, cpu_core_map[i]);
 584
 585         per_cpu(cpu_sibling_map, cpu) = cpu_core_map[cpu] = CPU_MASK_NONE;
 586 }
 587
 588 static void
 589 remove_siblinginfo(int cpu)
 590 {
 591         int last = 0;
 592
 593         if (cpu_data(cpu)->threads_per_core == 1 &&
 594             cpu_data(cpu)->cores_per_socket == 1) {
 595                 cpu_clear(cpu, cpu_core_map[cpu]);
 596                 cpu_clear(cpu, per_cpu(cpu_sibling_map, cpu));
 597                 return;
 598         }
 599
 600         last = (cpus_weight(cpu_core_map[cpu]) == 1 ? 1 : 0);
 601
 602         /* remove it from all sibling map's */
 603         clear_cpu_sibling_map(cpu);
 604 }
 605
 606 extern void fixup_irqs(void);
 607
 608 int migrate_platform_irqs(unsigned int cpu)
 609 {
 610         int new_cpei_cpu;
 611         struct irq_data *data = NULL;
 612         const struct cpumask *mask;
 613         int             retval = 0;
 614
 615         /*
 616          * dont permit CPEI target to removed.
 617          */
 618         if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
 619                 printk ("CPU (%d) is CPEI Target\n", cpu);
 620                 if (can_cpei_retarget()) {
 621                         /*
 622                          * Now re-target the CPEI to a different processor
 623                          */
 624                         new_cpei_cpu = cpumask_any(cpu_online_mask);
 625                         mask = cpumask_of(new_cpei_cpu);
 626                         set_cpei_target_cpu(new_cpei_cpu);
 627                         data = irq_get_irq_data(ia64_cpe_irq);
 628                         /*
 629                          * Switch for now, immediately, we need to do fake intr
 630                          * as other interrupts, but need to study CPEI behaviour with
 631                          * polling before making changes.
 632                          */
 633                         if (data && data->chip) {
 634                                 data->chip->irq_disable(data);
 635                                 data->chip->irq_set_affinity(data, mask, false);
 636                                 data->chip->irq_enable(data);
 637                                 printk ("Re-targeting CPEI to cpu %d\n", new_cpei_cpu);
 638                         }
 639                 }
 640                 if (!data) {
 641                         printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
 642                         retval = -EBUSY;
 643                 }
 644         }
 645         return retval;
 646 }
 647
 648 /* must be called with cpucontrol mutex held */
 649 int __cpu_disable(void)
 650 {
 651         int cpu = smp_processor_id();
 652
 653         /*
 654          * dont permit boot processor for now
 655          */
 656         if (cpu == 0 && !bsp_remove_ok) {
 657                 printk ("Your platform does not support removal of BSP\n");
 658                 return (-EBUSY);
 659         }
 660
 661         if (ia64_platform_is("sn2")) {
 662                 if (!sn_cpu_disable_allowed(cpu))
 663                         return -EBUSY;
 664         }
 665
 666         set_cpu_online(cpu, false);
 667
 668         if (migrate_platform_irqs(cpu)) {
 669                 set_cpu_online(cpu, true);
 670                 return -EBUSY;
 671         }
 672
 673         remove_siblinginfo(cpu);
 674         fixup_irqs();
 675         local_flush_tlb_all();
 676         cpu_clear(cpu, cpu_callin_map);
 677         return 0;
 678 }
 679
 680 void __cpu_die(unsigned int cpu)
 681 {
 682         unsigned int i;
 683
 684         for (i = 0; i < 100; i++) {
 685                 /* They ack this in play_dead by setting CPU_DEAD */
 686                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 687                 {
 688                         printk ("CPU %d is now offline\n", cpu);
 689                         return;
 690                 }
 691                 msleep(100);
 692         }
 693         printk(KERN_ERR "CPU %u didn't die...\n", cpu);
 694 }
 695 #endif /* CONFIG_HOTPLUG_CPU */
 696
 697 void
 698 smp_cpus_done (unsigned int dummy)
 699 {
 700         int cpu;
 701         unsigned long bogosum = 0;
 702
 703         /*
 704          * Allow the user to impress friends.
 705          */
 706
 707         for_each_online_cpu(cpu) {
 708                 bogosum += cpu_data(cpu)->loops_per_jiffy;
 709         }
 710
 711         printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
 712                (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
 713 }
 714
 715 static inline void set_cpu_sibling_map(int cpu)
 716 {
 717         int i;
 718
 719         for_each_online_cpu(i) {
 720                 if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
 721                         cpu_set(i, cpu_core_map[cpu]);
 722                         cpu_set(cpu, cpu_core_map[i]);
 723                         if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
 724                                 cpu_set(i, per_cpu(cpu_sibling_map, cpu));
 725                                 cpu_set(cpu, per_cpu(cpu_sibling_map, i));
 726                         }
 727                 }
 728         }
 729 }
 730
 731 int
 732 __cpu_up(unsigned int cpu, struct task_struct *tidle)
 733 {
 734         int ret;
 735         int sapicid;
 736
 737         sapicid = ia64_cpu_to_sapicid[cpu];
 738         if (sapicid == -1)
 739                 return -EINVAL;
 740
 741         /*
 742          * Already booted cpu? not valid anymore since we dont
 743          * do idle loop tightspin anymore.
 744          */
 745         if (cpu_isset(cpu, cpu_callin_map))
 746                 return -EINVAL;
 747
 748         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 749         /* Processor goes to start_secondary(), sets online flag */
 750         ret = do_boot_cpu(sapicid, cpu, tidle);
 751         if (ret < 0)
 752                 return ret;
 753
 754         if (cpu_data(cpu)->threads_per_core == 1 &&
 755             cpu_data(cpu)->cores_per_socket == 1) {
 756                 cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
 757                 cpu_set(cpu, cpu_core_map[cpu]);
 758                 return 0;
 759         }
 760
 761         set_cpu_sibling_map(cpu);
 762
 763         return 0;
 764 }
 765
 766 /*
 767  * Assume that CPUs have been discovered by some platform-dependent interface.  For
 768  * SoftSDV/Lion, that would be ACPI.
 769  *
 770  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
 771  */
 772 void __init
 773 init_smp_config(void)
 774 {
 775         struct fptr {
 776                 unsigned long fp;
 777                 unsigned long gp;
 778         } *ap_startup;
 779         long sal_ret;
 780
 781         /* Tell SAL where to drop the APs.  */
 782         ap_startup = (struct fptr *) start_ap;
 783         sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
 784                                        ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
 785         if (sal_ret < 0)
 786                 printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
 787                        ia64_sal_strerror(sal_ret));
 788 }
 789
 790 /*
 791  * identify_siblings(cpu) gets called from identify_cpu. This populates the
 792  * information related to logical execution units in per_cpu_data structure.
 793  */
 794 void identify_siblings(struct cpuinfo_ia64 *c)
 795 {
 796         long status;
 797         u16 pltid;
 798         pal_logical_to_physical_t info;
 799
 800         status = ia64_pal_logical_to_phys(-1, &info);
 801         if (status != PAL_STATUS_SUCCESS) {
 802                 if (status != PAL_STATUS_UNIMPLEMENTED) {
 803                         printk(KERN_ERR
 804                                 "ia64_pal_logical_to_phys failed with %ld\n",
 805                                 status);
 806                         return;
 807                 }
 808
 809                 info.overview_ppid = 0;
 810                 info.overview_cpp  = 1;
 811                 info.overview_tpc  = 1;
 812         }
 813
 814         status = ia64_sal_physical_id_info(&pltid);
 815         if (status != PAL_STATUS_SUCCESS) {
 816                 if (status != PAL_STATUS_UNIMPLEMENTED)
 817                         printk(KERN_ERR
 818                                 "ia64_sal_pltid failed with %ld\n",
 819                                 status);
 820                 return;
 821         }
 822
 823         c->socket_id =  (pltid << 8) | info.overview_ppid;
 824
 825         if (info.overview_cpp == 1 && info.overview_tpc == 1)
 826                 return;
 827
 828         c->cores_per_socket = info.overview_cpp;
 829         c->threads_per_core = info.overview_tpc;
 830         c->num_log = info.overview_num_log;
 831
 832         c->core_id = info.log1_cid;
 833         c->thread_id = info.log1_tid;
 834 }
 835
 836 /*
 837  * returns non zero, if multi-threading is enabled
 838  * on at least one physical package. Due to hotplug cpu
 839  * and (maxcpus=), all threads may not necessarily be enabled
 840  * even though the processor supports multi-threading.
 841  */
 842 int is_multithreading_enabled(void)
 843 {
 844         int i, j;
 845
 846         for_each_present_cpu(i) {
 847                 for_each_present_cpu(j) {
 848                         if (j == i)
 849                                 continue;
 850                         if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
 851                                 if (cpu_data(j)->core_id == cpu_data(i)->core_id)
 852                                         return 1;
 853                         }
 854                 }
 855         }
 856         return 0;
 857 }
 858 EXPORT_SYMBOL_GPL(is_multithreading_enabled);