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 <davidm@hpl.hp.com>
   6  * Copyright (C) 2001, 2004-2005 Intel Corp
   7  *      Rohit Seth <rohit.seth@intel.com>
   8  *      Suresh Siddha <suresh.b.siddha@intel.com>
   9  *      Gordon Jin <gordon.jin@intel.com>
  10  *      Ashok Raj  <ashok.raj@intel.com>
  11  *
  12  * 01/05/16 Rohit Seth <rohit.seth@intel.com>   Moved SMP booting functions from smp.c to here.
  13  * 01/04/27 David Mosberger <davidm@hpl.hp.com> Added ITC synching code.
  14  * 02/07/31 David Mosberger <davidm@hpl.hp.com> 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           <ashok.raj@intel.com> Added CPU Hotplug Support
  18  * 04/12/26 Jin Gordon <gordon.jin@intel.com>
  19  * 04/12/26 Rohit Seth <rohit.seth@intel.com>
  20  *                                              Add multi-threading and multi-core detection
  21  * 05/01/30 Suresh Siddha <suresh.b.siddha@intel.com>
  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 <asm/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/system.h>
  59 #include <asm/tlbflush.h>
  60 #include <asm/unistd.h>
  61 #include <asm/sn/arch.h>
  62
  63 #define SMP_DEBUG 0
  64
  65 #if SMP_DEBUG
  66 #define Dprintk(x...)  printk(x)
  67 #else
  68 #define Dprintk(x...)
  69 #endif
  70
  71 #ifdef CONFIG_HOTPLUG_CPU
  72 #ifdef CONFIG_PERMIT_BSP_REMOVE
  73 #define bsp_remove_ok   1
  74 #else
  75 #define bsp_remove_ok   0
  76 #endif
  77
  78 /*
  79  * Store all idle threads, this can be reused instead of creating
  80  * a new thread. Also avoids complicated thread destroy functionality
  81  * for idle threads.
  82  */
  83 struct task_struct *idle_thread_array[NR_CPUS];
  84
  85 /*
  86  * Global array allocated for NR_CPUS at boot time
  87  */
  88 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
  89
  90 /*
  91  * start_ap in head.S uses this to store current booting cpu
  92  * info.
  93  */
  94 struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
  95
  96 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
  97
  98 #define get_idle_for_cpu(x)             (idle_thread_array[(x)])
  99 #define set_idle_for_cpu(x,p)   (idle_thread_array[(x)] = (p))
 100
 101 #else
 102
 103 #define get_idle_for_cpu(x)             (NULL)
 104 #define set_idle_for_cpu(x,p)
 105 #define set_brendez_area(x)
 106 #endif
 107
 108
 109 /*
 110  * ITC synchronization related stuff:
 111  */
 112 #define MASTER  (0)
 113 #define SLAVE   (SMP_CACHE_BYTES/8)
 114
 115 #define NUM_ROUNDS      64      /* magic value */
 116 #define NUM_ITERS       5       /* likewise */
 117
 118 static DEFINE_SPINLOCK(itc_sync_lock);
 119 static volatile unsigned long go[SLAVE + 1];
 120
 121 #define DEBUG_ITC_SYNC  0
 122
 123 extern void start_ap (void);
 124 extern unsigned long ia64_iobase;
 125
 126 struct task_struct *task_for_booting_cpu;
 127
 128 /*
 129  * State for each CPU
 130  */
 131 DEFINE_PER_CPU(int, cpu_state);
 132
 133 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
 134 EXPORT_SYMBOL(cpu_core_map);
 135 DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
 136 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
 137
 138 int smp_num_siblings = 1;
 139
 140 /* which logical CPU number maps to which CPU (physical APIC ID) */
 141 volatile int ia64_cpu_to_sapicid[NR_CPUS];
 142 EXPORT_SYMBOL(ia64_cpu_to_sapicid);
 143
 144 static volatile cpumask_t cpu_callin_map;
 145
 146 struct smp_boot_data smp_boot_data __initdata;
 147
 148 unsigned long ap_wakeup_vector = -1; /* External Int use to wakeup APs */
 149
 150 char __initdata no_int_routing;
 151
 152 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
 153
 154 #ifdef CONFIG_FORCE_CPEI_RETARGET
 155 #define CPEI_OVERRIDE_DEFAULT   (1)
 156 #else
 157 #define CPEI_OVERRIDE_DEFAULT   (0)
 158 #endif
 159
 160 unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
 161
 162 static int __init
 163 cmdl_force_cpei(char *str)
 164 {
 165         int value=0;
 166
 167         get_option (&str, &value);
 168         force_cpei_retarget = value;
 169
 170         return 1;
 171 }
 172
 173 __setup("force_cpei=", cmdl_force_cpei);
 174
 175 static int __init
 176 nointroute (char *str)
 177 {
 178         no_int_routing = 1;
 179         printk ("no_int_routing on\n");
 180         return 1;
 181 }
 182
 183 __setup("nointroute", nointroute);
 184
 185 static void fix_b0_for_bsp(void)
 186 {
 187 #ifdef CONFIG_HOTPLUG_CPU
 188         int cpuid;
 189         static int fix_bsp_b0 = 1;
 190
 191         cpuid = smp_processor_id();
 192
 193         /*
 194          * Cache the b0 value on the first AP that comes up
 195          */
 196         if (!(fix_bsp_b0 && cpuid))
 197                 return;
 198
 199         sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
 200         printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
 201
 202         fix_bsp_b0 = 0;
 203 #endif
 204 }
 205
 206 void
 207 sync_master (void *arg)
 208 {
 209         unsigned long flags, i;
 210
 211         go[MASTER] = 0;
 212
 213         local_irq_save(flags);
 214         {
 215                 for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
 216                         while (!go[MASTER])
 217                                 cpu_relax();
 218                         go[MASTER] = 0;
 219                         go[SLAVE] = ia64_get_itc();
 220                 }
 221         }
 222         local_irq_restore(flags);
 223 }
 224
 225 /*
 226  * Return the number of cycles by which our itc differs from the itc on the master
 227  * (time-keeper) CPU.  A positive number indicates our itc is ahead of the master,
 228  * negative that it is behind.
 229  */
 230 static inline long
 231 get_delta (long *rt, long *master)
 232 {
 233         unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
 234         unsigned long tcenter, t0, t1, tm;
 235         long i;
 236
 237         for (i = 0; i < NUM_ITERS; ++i) {
 238                 t0 = ia64_get_itc();
 239                 go[MASTER] = 1;
 240                 while (!(tm = go[SLAVE]))
 241                         cpu_relax();
 242                 go[SLAVE] = 0;
 243                 t1 = ia64_get_itc();
 244
 245                 if (t1 - t0 < best_t1 - best_t0)
 246                         best_t0 = t0, best_t1 = t1, best_tm = tm;
 247         }
 248
 249         *rt = best_t1 - best_t0;
 250         *master = best_tm - best_t0;
 251
 252         /* average best_t0 and best_t1 without overflow: */
 253         tcenter = (best_t0/2 + best_t1/2);
 254         if (best_t0 % 2 + best_t1 % 2 == 2)
 255                 ++tcenter;
 256         return tcenter - best_tm;
 257 }
 258
 259 /*
 260  * Synchronize ar.itc of the current (slave) CPU with the ar.itc of the MASTER CPU
 261  * (normally the time-keeper CPU).  We use a closed loop to eliminate the possibility of
 262  * unaccounted-for errors (such as getting a machine check in the middle of a calibration
 263  * step).  The basic idea is for the slave to ask the master what itc value it has and to
 264  * read its own itc before and after the master responds.  Each iteration gives us three
 265  * timestamps:
 266  *
 267  *      slave           master
 268  *
 269  *      t0 ---\
 270  *             ---\
 271  *                 --->
 272  *                      tm
 273  *                 /---
 274  *             /---
 275  *      t1 <---
 276  *
 277  *
 278  * The goal is to adjust the slave's ar.itc such that tm falls exactly half-way between t0
 279  * and t1.  If we achieve this, the clocks are synchronized provided the interconnect
 280  * between the slave and the master is symmetric.  Even if the interconnect were
 281  * asymmetric, we would still know that the synchronization error is smaller than the
 282  * roundtrip latency (t0 - t1).
 283  *
 284  * When the interconnect is quiet and symmetric, this lets us synchronize the itc to
 285  * within one or two cycles.  However, we can only *guarantee* that the synchronization is
 286  * accurate to within a round-trip time, which is typically in the range of several
 287  * hundred cycles (e.g., ~500 cycles).  In practice, this means that the itc's are usually
 288  * almost perfectly synchronized, but we shouldn't assume that the accuracy is much better
 289  * than half a micro second or so.
 290  */
 291 void
 292 ia64_sync_itc (unsigned int master)
 293 {
 294         long i, delta, adj, adjust_latency = 0, done = 0;
 295         unsigned long flags, rt, master_time_stamp, bound;
 296 #if DEBUG_ITC_SYNC
 297         struct {
 298                 long rt;        /* roundtrip time */
 299                 long master;    /* master's timestamp */
 300                 long diff;      /* difference between midpoint and master's timestamp */
 301                 long lat;       /* estimate of itc adjustment latency */
 302         } t[NUM_ROUNDS];
 303 #endif
 304
 305         /*
 306          * Make sure local timer ticks are disabled while we sync.  If
 307          * they were enabled, we'd have to worry about nasty issues
 308          * like setting the ITC ahead of (or a long time before) the
 309          * next scheduled tick.
 310          */
 311         BUG_ON((ia64_get_itv() & (1 << 16)) == 0);
 312
 313         go[MASTER] = 1;
 314
 315         if (smp_call_function_single(master, sync_master, NULL, 0) < 0) {
 316                 printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
 317                 return;
 318         }
 319
 320         while (go[MASTER])
 321                 cpu_relax();    /* wait for master to be ready */
 322
 323         spin_lock_irqsave(&itc_sync_lock, flags);
 324         {
 325                 for (i = 0; i < NUM_ROUNDS; ++i) {
 326                         delta = get_delta(&rt, &master_time_stamp);
 327                         if (delta == 0) {
 328                                 done = 1;       /* let's lock on to this... */
 329                                 bound = rt;
 330                         }
 331
 332                         if (!done) {
 333                                 if (i > 0) {
 334                                         adjust_latency += -delta;
 335                                         adj = -delta + adjust_latency/4;
 336                                 } else
 337                                         adj = -delta;
 338
 339                                 ia64_set_itc(ia64_get_itc() + adj);
 340                         }
 341 #if DEBUG_ITC_SYNC
 342                         t[i].rt = rt;
 343                         t[i].master = master_time_stamp;
 344                         t[i].diff = delta;
 345                         t[i].lat = adjust_latency/4;
 346 #endif
 347                 }
 348         }
 349         spin_unlock_irqrestore(&itc_sync_lock, flags);
 350
 351 #if DEBUG_ITC_SYNC
 352         for (i = 0; i < NUM_ROUNDS; ++i)
 353                 printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
 354                        t[i].rt, t[i].master, t[i].diff, t[i].lat);
 355 #endif
 356
 357         printk(KERN_INFO "CPU %d: synchronized ITC with CPU %u (last diff %ld cycles, "
 358                "maxerr %lu cycles)\n", smp_processor_id(), master, delta, rt);
 359 }
 360
 361 /*
 362  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
 363  */
 364 static inline void __devinit
 365 smp_setup_percpu_timer (void)
 366 {
 367 }
 368
 369 static void __cpuinit
 370 smp_callin (void)
 371 {
 372         int cpuid, phys_id, itc_master;
 373         struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
 374         extern void ia64_init_itm(void);
 375         extern volatile int time_keeper_id;
 376
 377 #ifdef CONFIG_PERFMON
 378         extern void pfm_init_percpu(void);
 379 #endif
 380
 381         cpuid = smp_processor_id();
 382         phys_id = hard_smp_processor_id();
 383         itc_master = time_keeper_id;
 384
 385         if (cpu_online(cpuid)) {
 386                 printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
 387                        phys_id, cpuid);
 388                 BUG();
 389         }
 390
 391         fix_b0_for_bsp();
 392
 393         ipi_call_lock_irq();
 394         spin_lock(&vector_lock);
 395         /* Setup the per cpu irq handling data structures */
 396         __setup_vector_irq(cpuid);
 397         notify_cpu_starting(cpuid);
 398         cpu_set(cpuid, cpu_online_map);
 399         per_cpu(cpu_state, cpuid) = CPU_ONLINE;
 400         spin_unlock(&vector_lock);
 401         ipi_call_unlock_irq();
 402
 403         smp_setup_percpu_timer();
 404
 405         ia64_mca_cmc_vector_setup();    /* Setup vector on AP */
 406
 407 #ifdef CONFIG_PERFMON
 408         pfm_init_percpu();
 409 #endif
 410
 411         local_irq_enable();
 412
 413         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
 414                 /*
 415                  * Synchronize the ITC with the BP.  Need to do this after irqs are
 416                  * enabled because ia64_sync_itc() calls smp_call_function_single(), which
 417                  * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
 418                  * local_bh_enable(), which bugs out if irqs are not enabled...
 419                  */
 420                 Dprintk("Going to syncup ITC with ITC Master.\n");
 421                 ia64_sync_itc(itc_master);
 422         }
 423
 424         /*
 425          * Get our bogomips.
 426          */
 427         ia64_init_itm();
 428
 429         /*
 430          * Delay calibration can be skipped if new processor is identical to the
 431          * previous processor.
 432          */
 433         last_cpuinfo = cpu_data(cpuid - 1);
 434         this_cpuinfo = local_cpu_data;
 435         if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
 436             last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
 437             last_cpuinfo->features != this_cpuinfo->features ||
 438             last_cpuinfo->revision != this_cpuinfo->revision ||
 439             last_cpuinfo->family != this_cpuinfo->family ||
 440             last_cpuinfo->archrev != this_cpuinfo->archrev ||
 441             last_cpuinfo->model != this_cpuinfo->model)
 442                 calibrate_delay();
 443         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 444
 445         /*
 446          * Allow the master to continue.
 447          */
 448         cpu_set(cpuid, cpu_callin_map);
 449         Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
 450 }
 451
 452
 453 /*
 454  * Activate a secondary processor.  head.S calls this.
 455  */
 456 int __cpuinit
 457 start_secondary (void *unused)
 458 {
 459         /* Early console may use I/O ports */
 460         ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
 461 #ifndef CONFIG_PRINTK_TIME
 462         Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
 463 #endif
 464         efi_map_pal_code();
 465         cpu_init();
 466         preempt_disable();
 467         smp_callin();
 468
 469         cpu_idle();
 470         return 0;
 471 }
 472
 473 struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
 474 {
 475         return NULL;
 476 }
 477
 478 struct create_idle {
 479         struct work_struct work;
 480         struct task_struct *idle;
 481         struct completion done;
 482         int cpu;
 483 };
 484
 485 void __cpuinit
 486 do_fork_idle(struct work_struct *work)
 487 {
 488         struct create_idle *c_idle =
 489                 container_of(work, struct create_idle, work);
 490
 491         c_idle->idle = fork_idle(c_idle->cpu);
 492         complete(&c_idle->done);
 493 }
 494
 495 static int __cpuinit
 496 do_boot_cpu (int sapicid, int cpu)
 497 {
 498         int timeout;
 499         struct create_idle c_idle = {
 500                 .work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
 501                 .cpu    = cpu,
 502                 .done   = COMPLETION_INITIALIZER(c_idle.done),
 503         };
 504
 505         c_idle.idle = get_idle_for_cpu(cpu);
 506         if (c_idle.idle) {
 507                 init_idle(c_idle.idle, cpu);
 508                 goto do_rest;
 509         }
 510
 511         /*
 512          * We can't use kernel_thread since we must avoid to reschedule the child.
 513          */
 514         if (!keventd_up() || current_is_keventd())
 515                 c_idle.work.func(&c_idle.work);
 516         else {
 517                 schedule_work(&c_idle.work);
 518                 wait_for_completion(&c_idle.done);
 519         }
 520
 521         if (IS_ERR(c_idle.idle))
 522                 panic("failed fork for CPU %d", cpu);
 523
 524         set_idle_for_cpu(cpu, c_idle.idle);
 525
 526 do_rest:
 527         task_for_booting_cpu = c_idle.idle;
 528
 529         Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
 530
 531         set_brendez_area(cpu);
 532         platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
 533
 534         /*
 535          * Wait 10s total for the AP to start
 536          */
 537         Dprintk("Waiting on callin_map ...");
 538         for (timeout = 0; timeout < 100000; timeout++) {
 539                 if (cpu_isset(cpu, cpu_callin_map))
 540                         break;  /* It has booted */
 541                 udelay(100);
 542         }
 543         Dprintk("\n");
 544
 545         if (!cpu_isset(cpu, cpu_callin_map)) {
 546                 printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
 547                 ia64_cpu_to_sapicid[cpu] = -1;
 548                 cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
 549                 return -EINVAL;
 550         }
 551         return 0;
 552 }
 553
 554 static int __init
 555 decay (char *str)
 556 {
 557         int ticks;
 558         get_option (&str, &ticks);
 559         return 1;
 560 }
 561
 562 __setup("decay=", decay);
 563
 564 /*
 565  * Initialize the logical CPU number to SAPICID mapping
 566  */
 567 void __init
 568 smp_build_cpu_map (void)
 569 {
 570         int sapicid, cpu, i;
 571         int boot_cpu_id = hard_smp_processor_id();
 572
 573         for (cpu = 0; cpu < NR_CPUS; cpu++) {
 574                 ia64_cpu_to_sapicid[cpu] = -1;
 575         }
 576
 577         ia64_cpu_to_sapicid[0] = boot_cpu_id;
 578         cpus_clear(cpu_present_map);
 579         set_cpu_present(0, true);
 580         set_cpu_possible(0, true);
 581         for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
 582                 sapicid = smp_boot_data.cpu_phys_id[i];
 583                 if (sapicid == boot_cpu_id)
 584                         continue;
 585                 set_cpu_present(cpu, true);
 586                 set_cpu_possible(cpu, true);
 587                 ia64_cpu_to_sapicid[cpu] = sapicid;
 588                 cpu++;
 589         }
 590 }
 591
 592 /*
 593  * Cycle through the APs sending Wakeup IPIs to boot each.
 594  */
 595 void __init
 596 smp_prepare_cpus (unsigned int max_cpus)
 597 {
 598         int boot_cpu_id = hard_smp_processor_id();
 599
 600         /*
 601          * Initialize the per-CPU profiling counter/multiplier
 602          */
 603
 604         smp_setup_percpu_timer();
 605
 606         /*
 607          * We have the boot CPU online for sure.
 608          */
 609         cpu_set(0, cpu_online_map);
 610         cpu_set(0, cpu_callin_map);
 611
 612         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 613         ia64_cpu_to_sapicid[0] = boot_cpu_id;
 614
 615         printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
 616
 617         current_thread_info()->cpu = 0;
 618
 619         /*
 620          * If SMP should be disabled, then really disable it!
 621          */
 622         if (!max_cpus) {
 623                 printk(KERN_INFO "SMP mode deactivated.\n");
 624                 init_cpu_online(cpumask_of(0));
 625                 init_cpu_present(cpumask_of(0));
 626                 init_cpu_possible(cpumask_of(0));
 627                 return;
 628         }
 629 }
 630
 631 void __devinit smp_prepare_boot_cpu(void)
 632 {
 633         cpu_set(smp_processor_id(), cpu_online_map);
 634         cpu_set(smp_processor_id(), cpu_callin_map);
 635         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
 636         paravirt_post_smp_prepare_boot_cpu();
 637 }
 638
 639 #ifdef CONFIG_HOTPLUG_CPU
 640 static inline void
 641 clear_cpu_sibling_map(int cpu)
 642 {
 643         int i;
 644
 645         for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu))
 646                 cpu_clear(cpu, per_cpu(cpu_sibling_map, i));
 647         for_each_cpu_mask(i, cpu_core_map[cpu])
 648                 cpu_clear(cpu, cpu_core_map[i]);
 649
 650         per_cpu(cpu_sibling_map, cpu) = cpu_core_map[cpu] = CPU_MASK_NONE;
 651 }
 652
 653 static void
 654 remove_siblinginfo(int cpu)
 655 {
 656         int last = 0;
 657
 658         if (cpu_data(cpu)->threads_per_core == 1 &&
 659             cpu_data(cpu)->cores_per_socket == 1) {
 660                 cpu_clear(cpu, cpu_core_map[cpu]);
 661                 cpu_clear(cpu, per_cpu(cpu_sibling_map, cpu));
 662                 return;
 663         }
 664
 665         last = (cpus_weight(cpu_core_map[cpu]) == 1 ? 1 : 0);
 666
 667         /* remove it from all sibling map's */
 668         clear_cpu_sibling_map(cpu);
 669 }
 670
 671 extern void fixup_irqs(void);
 672
 673 int migrate_platform_irqs(unsigned int cpu)
 674 {
 675         int new_cpei_cpu;
 676         struct irq_desc *desc = NULL;
 677         const struct cpumask *mask;
 678         int             retval = 0;
 679
 680         /*
 681          * dont permit CPEI target to removed.
 682          */
 683         if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
 684                 printk ("CPU (%d) is CPEI Target\n", cpu);
 685                 if (can_cpei_retarget()) {
 686                         /*
 687                          * Now re-target the CPEI to a different processor
 688                          */
 689                         new_cpei_cpu = any_online_cpu(cpu_online_map);
 690                         mask = cpumask_of(new_cpei_cpu);
 691                         set_cpei_target_cpu(new_cpei_cpu);
 692                         desc = irq_desc + ia64_cpe_irq;
 693                         /*
 694                          * Switch for now, immediately, we need to do fake intr
 695                          * as other interrupts, but need to study CPEI behaviour with
 696                          * polling before making changes.
 697                          */
 698                         if (desc) {
 699                                 desc->chip->disable(ia64_cpe_irq);
 700                                 desc->chip->set_affinity(ia64_cpe_irq, mask);
 701                                 desc->chip->enable(ia64_cpe_irq);
 702                                 printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
 703                         }
 704                 }
 705                 if (!desc) {
 706                         printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
 707                         retval = -EBUSY;
 708                 }
 709         }
 710         return retval;
 711 }
 712
 713 /* must be called with cpucontrol mutex held */
 714 int __cpu_disable(void)
 715 {
 716         int cpu = smp_processor_id();
 717
 718         /*
 719          * dont permit boot processor for now
 720          */
 721         if (cpu == 0 && !bsp_remove_ok) {
 722                 printk ("Your platform does not support removal of BSP\n");
 723                 return (-EBUSY);
 724         }
 725
 726         if (ia64_platform_is("sn2")) {
 727                 if (!sn_cpu_disable_allowed(cpu))
 728                         return -EBUSY;
 729         }
 730
 731         cpu_clear(cpu, cpu_online_map);
 732
 733         if (migrate_platform_irqs(cpu)) {
 734                 cpu_set(cpu, cpu_online_map);
 735                 return -EBUSY;
 736         }
 737
 738         remove_siblinginfo(cpu);
 739         fixup_irqs();
 740         local_flush_tlb_all();
 741         cpu_clear(cpu, cpu_callin_map);
 742         return 0;
 743 }
 744
 745 void __cpu_die(unsigned int cpu)
 746 {
 747         unsigned int i;
 748
 749         for (i = 0; i < 100; i++) {
 750                 /* They ack this in play_dead by setting CPU_DEAD */
 751                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
 752                 {
 753                         printk ("CPU %d is now offline\n", cpu);
 754                         return;
 755                 }
 756                 msleep(100);
 757         }
 758         printk(KERN_ERR "CPU %u didn't die...\n", cpu);
 759 }
 760 #endif /* CONFIG_HOTPLUG_CPU */
 761
 762 void
 763 smp_cpus_done (unsigned int dummy)
 764 {
 765         int cpu;
 766         unsigned long bogosum = 0;
 767
 768         /*
 769          * Allow the user to impress friends.
 770          */
 771
 772         for_each_online_cpu(cpu) {
 773                 bogosum += cpu_data(cpu)->loops_per_jiffy;
 774         }
 775
 776         printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
 777                (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
 778 }
 779
 780 static inline void __devinit
 781 set_cpu_sibling_map(int cpu)
 782 {
 783         int i;
 784
 785         for_each_online_cpu(i) {
 786                 if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
 787                         cpu_set(i, cpu_core_map[cpu]);
 788                         cpu_set(cpu, cpu_core_map[i]);
 789                         if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
 790                                 cpu_set(i, per_cpu(cpu_sibling_map, cpu));
 791                                 cpu_set(cpu, per_cpu(cpu_sibling_map, i));
 792                         }
 793                 }
 794         }
 795 }
 796
 797 int __cpuinit
 798 __cpu_up (unsigned int cpu)
 799 {
 800         int ret;
 801         int sapicid;
 802
 803         sapicid = ia64_cpu_to_sapicid[cpu];
 804         if (sapicid == -1)
 805                 return -EINVAL;
 806
 807         /*
 808          * Already booted cpu? not valid anymore since we dont
 809          * do idle loop tightspin anymore.
 810          */
 811         if (cpu_isset(cpu, cpu_callin_map))
 812                 return -EINVAL;
 813
 814         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
 815         /* Processor goes to start_secondary(), sets online flag */
 816         ret = do_boot_cpu(sapicid, cpu);
 817         if (ret < 0)
 818                 return ret;
 819
 820         if (cpu_data(cpu)->threads_per_core == 1 &&
 821             cpu_data(cpu)->cores_per_socket == 1) {
 822                 cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
 823                 cpu_set(cpu, cpu_core_map[cpu]);
 824                 return 0;
 825         }
 826
 827         set_cpu_sibling_map(cpu);
 828
 829         return 0;
 830 }
 831
 832 /*
 833  * Assume that CPUs have been discovered by some platform-dependent interface.  For
 834  * SoftSDV/Lion, that would be ACPI.
 835  *
 836  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
 837  */
 838 void __init
 839 init_smp_config(void)
 840 {
 841         struct fptr {
 842                 unsigned long fp;
 843                 unsigned long gp;
 844         } *ap_startup;
 845         long sal_ret;
 846
 847         /* Tell SAL where to drop the APs.  */
 848         ap_startup = (struct fptr *) start_ap;
 849         sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
 850                                        ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
 851         if (sal_ret < 0)
 852                 printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
 853                        ia64_sal_strerror(sal_ret));
 854 }
 855
 856 /*
 857  * identify_siblings(cpu) gets called from identify_cpu. This populates the
 858  * information related to logical execution units in per_cpu_data structure.
 859  */
 860 void __devinit
 861 identify_siblings(struct cpuinfo_ia64 *c)
 862 {
 863         long status;
 864         u16 pltid;
 865         pal_logical_to_physical_t info;
 866
 867         status = ia64_pal_logical_to_phys(-1, &info);
 868         if (status != PAL_STATUS_SUCCESS) {
 869                 if (status != PAL_STATUS_UNIMPLEMENTED) {
 870                         printk(KERN_ERR
 871                                 "ia64_pal_logical_to_phys failed with %ld\n",
 872                                 status);
 873                         return;
 874                 }
 875
 876                 info.overview_ppid = 0;
 877                 info.overview_cpp  = 1;
 878                 info.overview_tpc  = 1;
 879         }
 880
 881         status = ia64_sal_physical_id_info(&pltid);
 882         if (status != PAL_STATUS_SUCCESS) {
 883                 if (status != PAL_STATUS_UNIMPLEMENTED)
 884                         printk(KERN_ERR
 885                                 "ia64_sal_pltid failed with %ld\n",
 886                                 status);
 887                 return;
 888         }
 889
 890         c->socket_id =  (pltid << 8) | info.overview_ppid;
 891
 892         if (info.overview_cpp == 1 && info.overview_tpc == 1)
 893                 return;
 894
 895         c->cores_per_socket = info.overview_cpp;
 896         c->threads_per_core = info.overview_tpc;
 897         c->num_log = info.overview_num_log;
 898
 899         c->core_id = info.log1_cid;
 900         c->thread_id = info.log1_tid;
 901 }
 902
 903 /*
 904  * returns non zero, if multi-threading is enabled
 905  * on at least one physical package. Due to hotplug cpu
 906  * and (maxcpus=), all threads may not necessarily be enabled
 907  * even though the processor supports multi-threading.
 908  */
 909 int is_multithreading_enabled(void)
 910 {
 911         int i, j;
 912
 913         for_each_present_cpu(i) {
 914                 for_each_present_cpu(j) {
 915                         if (j == i)
 916                                 continue;
 917                         if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
 918                                 if (cpu_data(j)->core_id == cpu_data(i)->core_id)
 919                                         return 1;
 920                         }
 921                 }
 922         }
 923         return 0;
 924 }
 925 EXPORT_SYMBOL_GPL(is_multithreading_enabled);