header cleaning: don't include smp_lock.h when not used
[linux-3.10.git] / 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/ia32.h>
48 #include <asm/io.h>
49 #include <asm/irq.h>
50 #include <asm/machvec.h>
51 #include <asm/mca.h>
52 #include <asm/page.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
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  * Store all idle threads, this can be reused instead of creating
79  * a new thread. Also avoids complicated thread destroy functionality
80  * for idle threads.
81  */
82 struct task_struct *idle_thread_array[NR_CPUS];
83
84 /*
85  * Global array allocated for NR_CPUS at boot time
86  */
87 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
88
89 /*
90  * start_ap in head.S uses this to store current booting cpu
91  * info.
92  */
93 struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
94
95 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
96
97 #define get_idle_for_cpu(x)             (idle_thread_array[(x)])
98 #define set_idle_for_cpu(x,p)   (idle_thread_array[(x)] = (p))
99
100 #else
101
102 #define get_idle_for_cpu(x)             (NULL)
103 #define set_idle_for_cpu(x,p)
104 #define set_brendez_area(x)
105 #endif
106
107
108 /*
109  * ITC synchronization related stuff:
110  */
111 #define MASTER  (0)
112 #define SLAVE   (SMP_CACHE_BYTES/8)
113
114 #define NUM_ROUNDS      64      /* magic value */
115 #define NUM_ITERS       5       /* likewise */
116
117 static DEFINE_SPINLOCK(itc_sync_lock);
118 static volatile unsigned long go[SLAVE + 1];
119
120 #define DEBUG_ITC_SYNC  0
121
122 extern void __devinit calibrate_delay (void);
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 /* Bitmasks of currently online, and possible CPUs */
134 cpumask_t cpu_online_map;
135 EXPORT_SYMBOL(cpu_online_map);
136 cpumask_t cpu_possible_map = CPU_MASK_NONE;
137 EXPORT_SYMBOL(cpu_possible_map);
138
139 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
140 cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
141 int smp_num_siblings = 1;
142 int smp_num_cpucores = 1;
143
144 /* which logical CPU number maps to which CPU (physical APIC ID) */
145 volatile int ia64_cpu_to_sapicid[NR_CPUS];
146 EXPORT_SYMBOL(ia64_cpu_to_sapicid);
147
148 static volatile cpumask_t cpu_callin_map;
149
150 struct smp_boot_data smp_boot_data __initdata;
151
152 unsigned long ap_wakeup_vector = -1; /* External Int use to wakeup APs */
153
154 char __initdata no_int_routing;
155
156 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
157
158 #ifdef CONFIG_FORCE_CPEI_RETARGET
159 #define CPEI_OVERRIDE_DEFAULT   (1)
160 #else
161 #define CPEI_OVERRIDE_DEFAULT   (0)
162 #endif
163
164 unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
165
166 static int __init
167 cmdl_force_cpei(char *str)
168 {
169         int value=0;
170
171         get_option (&str, &value);
172         force_cpei_retarget = value;
173
174         return 1;
175 }
176
177 __setup("force_cpei=", cmdl_force_cpei);
178
179 static int __init
180 nointroute (char *str)
181 {
182         no_int_routing = 1;
183         printk ("no_int_routing on\n");
184         return 1;
185 }
186
187 __setup("nointroute", nointroute);
188
189 static void fix_b0_for_bsp(void)
190 {
191 #ifdef CONFIG_HOTPLUG_CPU
192         int cpuid;
193         static int fix_bsp_b0 = 1;
194
195         cpuid = smp_processor_id();
196
197         /*
198          * Cache the b0 value on the first AP that comes up
199          */
200         if (!(fix_bsp_b0 && cpuid))
201                 return;
202
203         sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
204         printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
205
206         fix_bsp_b0 = 0;
207 #endif
208 }
209
210 void
211 sync_master (void *arg)
212 {
213         unsigned long flags, i;
214
215         go[MASTER] = 0;
216
217         local_irq_save(flags);
218         {
219                 for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
220                         while (!go[MASTER])
221                                 cpu_relax();
222                         go[MASTER] = 0;
223                         go[SLAVE] = ia64_get_itc();
224                 }
225         }
226         local_irq_restore(flags);
227 }
228
229 /*
230  * Return the number of cycles by which our itc differs from the itc on the master
231  * (time-keeper) CPU.  A positive number indicates our itc is ahead of the master,
232  * negative that it is behind.
233  */
234 static inline long
235 get_delta (long *rt, long *master)
236 {
237         unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
238         unsigned long tcenter, t0, t1, tm;
239         long i;
240
241         for (i = 0; i < NUM_ITERS; ++i) {
242                 t0 = ia64_get_itc();
243                 go[MASTER] = 1;
244                 while (!(tm = go[SLAVE]))
245                         cpu_relax();
246                 go[SLAVE] = 0;
247                 t1 = ia64_get_itc();
248
249                 if (t1 - t0 < best_t1 - best_t0)
250                         best_t0 = t0, best_t1 = t1, best_tm = tm;
251         }
252
253         *rt = best_t1 - best_t0;
254         *master = best_tm - best_t0;
255
256         /* average best_t0 and best_t1 without overflow: */
257         tcenter = (best_t0/2 + best_t1/2);
258         if (best_t0 % 2 + best_t1 % 2 == 2)
259                 ++tcenter;
260         return tcenter - best_tm;
261 }
262
263 /*
264  * Synchronize ar.itc of the current (slave) CPU with the ar.itc of the MASTER CPU
265  * (normally the time-keeper CPU).  We use a closed loop to eliminate the possibility of
266  * unaccounted-for errors (such as getting a machine check in the middle of a calibration
267  * step).  The basic idea is for the slave to ask the master what itc value it has and to
268  * read its own itc before and after the master responds.  Each iteration gives us three
269  * timestamps:
270  *
271  *      slave           master
272  *
273  *      t0 ---\
274  *             ---\
275  *                 --->
276  *                      tm
277  *                 /---
278  *             /---
279  *      t1 <---
280  *
281  *
282  * The goal is to adjust the slave's ar.itc such that tm falls exactly half-way between t0
283  * and t1.  If we achieve this, the clocks are synchronized provided the interconnect
284  * between the slave and the master is symmetric.  Even if the interconnect were
285  * asymmetric, we would still know that the synchronization error is smaller than the
286  * roundtrip latency (t0 - t1).
287  *
288  * When the interconnect is quiet and symmetric, this lets us synchronize the itc to
289  * within one or two cycles.  However, we can only *guarantee* that the synchronization is
290  * accurate to within a round-trip time, which is typically in the range of several
291  * hundred cycles (e.g., ~500 cycles).  In practice, this means that the itc's are usually
292  * almost perfectly synchronized, but we shouldn't assume that the accuracy is much better
293  * than half a micro second or so.
294  */
295 void
296 ia64_sync_itc (unsigned int master)
297 {
298         long i, delta, adj, adjust_latency = 0, done = 0;
299         unsigned long flags, rt, master_time_stamp, bound;
300 #if DEBUG_ITC_SYNC
301         struct {
302                 long rt;        /* roundtrip time */
303                 long master;    /* master's timestamp */
304                 long diff;      /* difference between midpoint and master's timestamp */
305                 long lat;       /* estimate of itc adjustment latency */
306         } t[NUM_ROUNDS];
307 #endif
308
309         /*
310          * Make sure local timer ticks are disabled while we sync.  If
311          * they were enabled, we'd have to worry about nasty issues
312          * like setting the ITC ahead of (or a long time before) the
313          * next scheduled tick.
314          */
315         BUG_ON((ia64_get_itv() & (1 << 16)) == 0);
316
317         go[MASTER] = 1;
318
319         if (smp_call_function_single(master, sync_master, NULL, 1, 0) < 0) {
320                 printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
321                 return;
322         }
323
324         while (go[MASTER])
325                 cpu_relax();    /* wait for master to be ready */
326
327         spin_lock_irqsave(&itc_sync_lock, flags);
328         {
329                 for (i = 0; i < NUM_ROUNDS; ++i) {
330                         delta = get_delta(&rt, &master_time_stamp);
331                         if (delta == 0) {
332                                 done = 1;       /* let's lock on to this... */
333                                 bound = rt;
334                         }
335
336                         if (!done) {
337                                 if (i > 0) {
338                                         adjust_latency += -delta;
339                                         adj = -delta + adjust_latency/4;
340                                 } else
341                                         adj = -delta;
342
343                                 ia64_set_itc(ia64_get_itc() + adj);
344                         }
345 #if DEBUG_ITC_SYNC
346                         t[i].rt = rt;
347                         t[i].master = master_time_stamp;
348                         t[i].diff = delta;
349                         t[i].lat = adjust_latency/4;
350 #endif
351                 }
352         }
353         spin_unlock_irqrestore(&itc_sync_lock, flags);
354
355 #if DEBUG_ITC_SYNC
356         for (i = 0; i < NUM_ROUNDS; ++i)
357                 printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
358                        t[i].rt, t[i].master, t[i].diff, t[i].lat);
359 #endif
360
361         printk(KERN_INFO "CPU %d: synchronized ITC with CPU %u (last diff %ld cycles, "
362                "maxerr %lu cycles)\n", smp_processor_id(), master, delta, rt);
363 }
364
365 /*
366  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
367  */
368 static inline void __devinit
369 smp_setup_percpu_timer (void)
370 {
371 }
372
373 static void __devinit
374 smp_callin (void)
375 {
376         int cpuid, phys_id, itc_master;
377         struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
378         extern void ia64_init_itm(void);
379         extern volatile int time_keeper_id;
380
381 #ifdef CONFIG_PERFMON
382         extern void pfm_init_percpu(void);
383 #endif
384
385         cpuid = smp_processor_id();
386         phys_id = hard_smp_processor_id();
387         itc_master = time_keeper_id;
388
389         if (cpu_online(cpuid)) {
390                 printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
391                        phys_id, cpuid);
392                 BUG();
393         }
394
395         fix_b0_for_bsp();
396
397         lock_ipi_calllock();
398         cpu_set(cpuid, cpu_online_map);
399         unlock_ipi_calllock();
400         per_cpu(cpu_state, cpuid) = CPU_ONLINE;
401
402         smp_setup_percpu_timer();
403
404         ia64_mca_cmc_vector_setup();    /* Setup vector on AP */
405
406 #ifdef CONFIG_PERFMON
407         pfm_init_percpu();
408 #endif
409
410         local_irq_enable();
411
412         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
413                 /*
414                  * Synchronize the ITC with the BP.  Need to do this after irqs are
415                  * enabled because ia64_sync_itc() calls smp_call_function_single(), which
416                  * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
417                  * local_bh_enable(), which bugs out if irqs are not enabled...
418                  */
419                 Dprintk("Going to syncup ITC with ITC Master.\n");
420                 ia64_sync_itc(itc_master);
421         }
422
423         /*
424          * Get our bogomips.
425          */
426         ia64_init_itm();
427
428         /*
429          * Delay calibration can be skipped if new processor is identical to the
430          * previous processor.
431          */
432         last_cpuinfo = cpu_data(cpuid - 1);
433         this_cpuinfo = local_cpu_data;
434         if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
435             last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
436             last_cpuinfo->features != this_cpuinfo->features ||
437             last_cpuinfo->revision != this_cpuinfo->revision ||
438             last_cpuinfo->family != this_cpuinfo->family ||
439             last_cpuinfo->archrev != this_cpuinfo->archrev ||
440             last_cpuinfo->model != this_cpuinfo->model)
441                 calibrate_delay();
442         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
443
444 #ifdef CONFIG_IA32_SUPPORT
445         ia32_gdt_init();
446 #endif
447
448         /*
449          * Allow the master to continue.
450          */
451         cpu_set(cpuid, cpu_callin_map);
452         Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
453 }
454
455
456 /*
457  * Activate a secondary processor.  head.S calls this.
458  */
459 int __devinit
460 start_secondary (void *unused)
461 {
462         /* Early console may use I/O ports */
463         ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
464         Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
465         efi_map_pal_code();
466         cpu_init();
467         preempt_disable();
468         smp_callin();
469
470         cpu_idle();
471         return 0;
472 }
473
474 struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
475 {
476         return NULL;
477 }
478
479 struct create_idle {
480         struct work_struct work;
481         struct task_struct *idle;
482         struct completion done;
483         int cpu;
484 };
485
486 void
487 do_fork_idle(struct work_struct *work)
488 {
489         struct create_idle *c_idle =
490                 container_of(work, struct create_idle, work);
491
492         c_idle->idle = fork_idle(c_idle->cpu);
493         complete(&c_idle->done);
494 }
495
496 static int __devinit
497 do_boot_cpu (int sapicid, int cpu)
498 {
499         int timeout;
500         struct create_idle c_idle = {
501                 .work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
502                 .cpu    = cpu,
503                 .done   = COMPLETION_INITIALIZER(c_idle.done),
504         };
505
506         c_idle.idle = get_idle_for_cpu(cpu);
507         if (c_idle.idle) {
508                 init_idle(c_idle.idle, cpu);
509                 goto do_rest;
510         }
511
512         /*
513          * We can't use kernel_thread since we must avoid to reschedule the child.
514          */
515         if (!keventd_up() || current_is_keventd())
516                 c_idle.work.func(&c_idle.work);
517         else {
518                 schedule_work(&c_idle.work);
519                 wait_for_completion(&c_idle.done);
520         }
521
522         if (IS_ERR(c_idle.idle))
523                 panic("failed fork for CPU %d", cpu);
524
525         set_idle_for_cpu(cpu, c_idle.idle);
526
527 do_rest:
528         task_for_booting_cpu = c_idle.idle;
529
530         Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
531
532         set_brendez_area(cpu);
533         platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
534
535         /*
536          * Wait 10s total for the AP to start
537          */
538         Dprintk("Waiting on callin_map ...");
539         for (timeout = 0; timeout < 100000; timeout++) {
540                 if (cpu_isset(cpu, cpu_callin_map))
541                         break;  /* It has booted */
542                 udelay(100);
543         }
544         Dprintk("\n");
545
546         if (!cpu_isset(cpu, cpu_callin_map)) {
547                 printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
548                 ia64_cpu_to_sapicid[cpu] = -1;
549                 cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
550                 return -EINVAL;
551         }
552         return 0;
553 }
554
555 static int __init
556 decay (char *str)
557 {
558         int ticks;
559         get_option (&str, &ticks);
560         return 1;
561 }
562
563 __setup("decay=", decay);
564
565 /*
566  * Initialize the logical CPU number to SAPICID mapping
567  */
568 void __init
569 smp_build_cpu_map (void)
570 {
571         int sapicid, cpu, i;
572         int boot_cpu_id = hard_smp_processor_id();
573
574         for (cpu = 0; cpu < NR_CPUS; cpu++) {
575                 ia64_cpu_to_sapicid[cpu] = -1;
576         }
577
578         ia64_cpu_to_sapicid[0] = boot_cpu_id;
579         cpus_clear(cpu_present_map);
580         cpu_set(0, cpu_present_map);
581         cpu_set(0, cpu_possible_map);
582         for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
583                 sapicid = smp_boot_data.cpu_phys_id[i];
584                 if (sapicid == boot_cpu_id)
585                         continue;
586                 cpu_set(cpu, cpu_present_map);
587                 cpu_set(cpu, cpu_possible_map);
588                 ia64_cpu_to_sapicid[cpu] = sapicid;
589                 cpu++;
590         }
591 }
592
593 /*
594  * Cycle through the APs sending Wakeup IPIs to boot each.
595  */
596 void __init
597 smp_prepare_cpus (unsigned int max_cpus)
598 {
599         int boot_cpu_id = hard_smp_processor_id();
600
601         /*
602          * Initialize the per-CPU profiling counter/multiplier
603          */
604
605         smp_setup_percpu_timer();
606
607         /*
608          * We have the boot CPU online for sure.
609          */
610         cpu_set(0, cpu_online_map);
611         cpu_set(0, cpu_callin_map);
612
613         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
614         ia64_cpu_to_sapicid[0] = boot_cpu_id;
615
616         printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
617
618         current_thread_info()->cpu = 0;
619
620         /*
621          * If SMP should be disabled, then really disable it!
622          */
623         if (!max_cpus) {
624                 printk(KERN_INFO "SMP mode deactivated.\n");
625                 cpus_clear(cpu_online_map);
626                 cpus_clear(cpu_present_map);
627                 cpus_clear(cpu_possible_map);
628                 cpu_set(0, cpu_online_map);
629                 cpu_set(0, cpu_present_map);
630                 cpu_set(0, cpu_possible_map);
631                 return;
632         }
633 }
634
635 void __devinit smp_prepare_boot_cpu(void)
636 {
637         cpu_set(smp_processor_id(), cpu_online_map);
638         cpu_set(smp_processor_id(), cpu_callin_map);
639         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
640 }
641
642 #ifdef CONFIG_HOTPLUG_CPU
643 static inline void
644 clear_cpu_sibling_map(int cpu)
645 {
646         int i;
647
648         for_each_cpu_mask(i, cpu_sibling_map[cpu])
649                 cpu_clear(cpu, cpu_sibling_map[i]);
650         for_each_cpu_mask(i, cpu_core_map[cpu])
651                 cpu_clear(cpu, cpu_core_map[i]);
652
653         cpu_sibling_map[cpu] = cpu_core_map[cpu] = CPU_MASK_NONE;
654 }
655
656 static void
657 remove_siblinginfo(int cpu)
658 {
659         int last = 0;
660
661         if (cpu_data(cpu)->threads_per_core == 1 &&
662             cpu_data(cpu)->cores_per_socket == 1) {
663                 cpu_clear(cpu, cpu_core_map[cpu]);
664                 cpu_clear(cpu, cpu_sibling_map[cpu]);
665                 return;
666         }
667
668         last = (cpus_weight(cpu_core_map[cpu]) == 1 ? 1 : 0);
669
670         /* remove it from all sibling map's */
671         clear_cpu_sibling_map(cpu);
672 }
673
674 extern void fixup_irqs(void);
675
676 int migrate_platform_irqs(unsigned int cpu)
677 {
678         int new_cpei_cpu;
679         irq_desc_t *desc = NULL;
680         cpumask_t       mask;
681         int             retval = 0;
682
683         /*
684          * dont permit CPEI target to removed.
685          */
686         if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
687                 printk ("CPU (%d) is CPEI Target\n", cpu);
688                 if (can_cpei_retarget()) {
689                         /*
690                          * Now re-target the CPEI to a different processor
691                          */
692                         new_cpei_cpu = any_online_cpu(cpu_online_map);
693                         mask = cpumask_of_cpu(new_cpei_cpu);
694                         set_cpei_target_cpu(new_cpei_cpu);
695                         desc = irq_desc + ia64_cpe_irq;
696                         /*
697                          * Switch for now, immediatly, we need to do fake intr
698                          * as other interrupts, but need to study CPEI behaviour with
699                          * polling before making changes.
700                          */
701                         if (desc) {
702                                 desc->chip->disable(ia64_cpe_irq);
703                                 desc->chip->set_affinity(ia64_cpe_irq, mask);
704                                 desc->chip->enable(ia64_cpe_irq);
705                                 printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
706                         }
707                 }
708                 if (!desc) {
709                         printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
710                         retval = -EBUSY;
711                 }
712         }
713         return retval;
714 }
715
716 /* must be called with cpucontrol mutex held */
717 int __cpu_disable(void)
718 {
719         int cpu = smp_processor_id();
720
721         /*
722          * dont permit boot processor for now
723          */
724         if (cpu == 0 && !bsp_remove_ok) {
725                 printk ("Your platform does not support removal of BSP\n");
726                 return (-EBUSY);
727         }
728
729         cpu_clear(cpu, cpu_online_map);
730
731         if (migrate_platform_irqs(cpu)) {
732                 cpu_set(cpu, cpu_online_map);
733                 return (-EBUSY);
734         }
735
736         remove_siblinginfo(cpu);
737         cpu_clear(cpu, cpu_online_map);
738         fixup_irqs();
739         local_flush_tlb_all();
740         cpu_clear(cpu, cpu_callin_map);
741         return 0;
742 }
743
744 void __cpu_die(unsigned int cpu)
745 {
746         unsigned int i;
747
748         for (i = 0; i < 100; i++) {
749                 /* They ack this in play_dead by setting CPU_DEAD */
750                 if (per_cpu(cpu_state, cpu) == CPU_DEAD)
751                 {
752                         printk ("CPU %d is now offline\n", cpu);
753                         return;
754                 }
755                 msleep(100);
756         }
757         printk(KERN_ERR "CPU %u didn't die...\n", cpu);
758 }
759 #else /* !CONFIG_HOTPLUG_CPU */
760 int __cpu_disable(void)
761 {
762         return -ENOSYS;
763 }
764
765 void __cpu_die(unsigned int cpu)
766 {
767         /* We said "no" in __cpu_disable */
768         BUG();
769 }
770 #endif /* CONFIG_HOTPLUG_CPU */
771
772 void
773 smp_cpus_done (unsigned int dummy)
774 {
775         int cpu;
776         unsigned long bogosum = 0;
777
778         /*
779          * Allow the user to impress friends.
780          */
781
782         for_each_online_cpu(cpu) {
783                 bogosum += cpu_data(cpu)->loops_per_jiffy;
784         }
785
786         printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
787                (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
788 }
789
790 static inline void __devinit
791 set_cpu_sibling_map(int cpu)
792 {
793         int i;
794
795         for_each_online_cpu(i) {
796                 if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
797                         cpu_set(i, cpu_core_map[cpu]);
798                         cpu_set(cpu, cpu_core_map[i]);
799                         if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
800                                 cpu_set(i, cpu_sibling_map[cpu]);
801                                 cpu_set(cpu, cpu_sibling_map[i]);
802                         }
803                 }
804         }
805 }
806
807 int __devinit
808 __cpu_up (unsigned int cpu)
809 {
810         int ret;
811         int sapicid;
812
813         sapicid = ia64_cpu_to_sapicid[cpu];
814         if (sapicid == -1)
815                 return -EINVAL;
816
817         /*
818          * Already booted cpu? not valid anymore since we dont
819          * do idle loop tightspin anymore.
820          */
821         if (cpu_isset(cpu, cpu_callin_map))
822                 return -EINVAL;
823
824         per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
825         /* Processor goes to start_secondary(), sets online flag */
826         ret = do_boot_cpu(sapicid, cpu);
827         if (ret < 0)
828                 return ret;
829
830         if (cpu_data(cpu)->threads_per_core == 1 &&
831             cpu_data(cpu)->cores_per_socket == 1) {
832                 cpu_set(cpu, cpu_sibling_map[cpu]);
833                 cpu_set(cpu, cpu_core_map[cpu]);
834                 return 0;
835         }
836
837         set_cpu_sibling_map(cpu);
838
839         return 0;
840 }
841
842 /*
843  * Assume that CPU's have been discovered by some platform-dependent interface.  For
844  * SoftSDV/Lion, that would be ACPI.
845  *
846  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
847  */
848 void __init
849 init_smp_config(void)
850 {
851         struct fptr {
852                 unsigned long fp;
853                 unsigned long gp;
854         } *ap_startup;
855         long sal_ret;
856
857         /* Tell SAL where to drop the AP's.  */
858         ap_startup = (struct fptr *) start_ap;
859         sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
860                                        ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
861         if (sal_ret < 0)
862                 printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
863                        ia64_sal_strerror(sal_ret));
864 }
865
866 /*
867  * identify_siblings(cpu) gets called from identify_cpu. This populates the 
868  * information related to logical execution units in per_cpu_data structure.
869  */
870 void __devinit
871 identify_siblings(struct cpuinfo_ia64 *c)
872 {
873         s64 status;
874         u16 pltid;
875         pal_logical_to_physical_t info;
876
877         if (smp_num_cpucores == 1 && smp_num_siblings == 1)
878                 return;
879
880         if ((status = ia64_pal_logical_to_phys(-1, &info)) != PAL_STATUS_SUCCESS) {
881                 printk(KERN_ERR "ia64_pal_logical_to_phys failed with %ld\n",
882                        status);
883                 return;
884         }
885         if ((status = ia64_sal_physical_id_info(&pltid)) != PAL_STATUS_SUCCESS) {
886                 printk(KERN_ERR "ia64_sal_pltid failed with %ld\n", status);
887                 return;
888         }
889
890         c->socket_id =  (pltid << 8) | info.overview_ppid;
891         c->cores_per_socket = info.overview_cpp;
892         c->threads_per_core = info.overview_tpc;
893         c->num_log = info.overview_num_log;
894
895         c->core_id = info.log1_cid;
896         c->thread_id = info.log1_tid;
897 }
898
899 /*
900  * returns non zero, if multi-threading is enabled
901  * on at least one physical package. Due to hotplug cpu
902  * and (maxcpus=), all threads may not necessarily be enabled
903  * even though the processor supports multi-threading.
904  */
905 int is_multithreading_enabled(void)
906 {
907         int i, j;
908
909         for_each_present_cpu(i) {
910                 for_each_present_cpu(j) {
911                         if (j == i)
912                                 continue;
913                         if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
914                                 if (cpu_data(j)->core_id == cpu_data(i)->core_id)
915                                         return 1;
916                         }
917                 }
918         }
919         return 0;
920 }
921 EXPORT_SYMBOL_GPL(is_multithreading_enabled);