xref: /openbmc/linux/arch/ia64/kernel/smpboot.c (revision 8fa5723aa7e053d498336b48448b292fc2e0458b)
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/paravirt.h>
54 #include <asm/pgalloc.h>
55 #include <asm/pgtable.h>
56 #include <asm/processor.h>
57 #include <asm/ptrace.h>
58 #include <asm/sal.h>
59 #include <asm/system.h>
60 #include <asm/tlbflush.h>
61 #include <asm/unistd.h>
62 #include <asm/sn/arch.h>
63 
64 #define SMP_DEBUG 0
65 
66 #if SMP_DEBUG
67 #define Dprintk(x...)  printk(x)
68 #else
69 #define Dprintk(x...)
70 #endif
71 
72 #ifdef CONFIG_HOTPLUG_CPU
73 #ifdef CONFIG_PERMIT_BSP_REMOVE
74 #define bsp_remove_ok	1
75 #else
76 #define bsp_remove_ok	0
77 #endif
78 
79 /*
80  * Store all idle threads, this can be reused instead of creating
81  * a new thread. Also avoids complicated thread destroy functionality
82  * for idle threads.
83  */
84 struct task_struct *idle_thread_array[NR_CPUS];
85 
86 /*
87  * Global array allocated for NR_CPUS at boot time
88  */
89 struct sal_to_os_boot sal_boot_rendez_state[NR_CPUS];
90 
91 /*
92  * start_ap in head.S uses this to store current booting cpu
93  * info.
94  */
95 struct sal_to_os_boot *sal_state_for_booting_cpu = &sal_boot_rendez_state[0];
96 
97 #define set_brendez_area(x) (sal_state_for_booting_cpu = &sal_boot_rendez_state[(x)]);
98 
99 #define get_idle_for_cpu(x)		(idle_thread_array[(x)])
100 #define set_idle_for_cpu(x,p)	(idle_thread_array[(x)] = (p))
101 
102 #else
103 
104 #define get_idle_for_cpu(x)		(NULL)
105 #define set_idle_for_cpu(x,p)
106 #define set_brendez_area(x)
107 #endif
108 
109 
110 /*
111  * ITC synchronization related stuff:
112  */
113 #define MASTER	(0)
114 #define SLAVE	(SMP_CACHE_BYTES/8)
115 
116 #define NUM_ROUNDS	64	/* magic value */
117 #define NUM_ITERS	5	/* likewise */
118 
119 static DEFINE_SPINLOCK(itc_sync_lock);
120 static volatile unsigned long go[SLAVE + 1];
121 
122 #define DEBUG_ITC_SYNC	0
123 
124 extern void start_ap (void);
125 extern unsigned long ia64_iobase;
126 
127 struct task_struct *task_for_booting_cpu;
128 
129 /*
130  * State for each CPU
131  */
132 DEFINE_PER_CPU(int, cpu_state);
133 
134 /* Bitmasks of currently online, and possible CPUs */
135 cpumask_t cpu_online_map;
136 EXPORT_SYMBOL(cpu_online_map);
137 cpumask_t cpu_possible_map = CPU_MASK_NONE;
138 EXPORT_SYMBOL(cpu_possible_map);
139 
140 cpumask_t cpu_core_map[NR_CPUS] __cacheline_aligned;
141 EXPORT_SYMBOL(cpu_core_map);
142 DEFINE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
143 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
144 
145 int smp_num_siblings = 1;
146 
147 /* which logical CPU number maps to which CPU (physical APIC ID) */
148 volatile int ia64_cpu_to_sapicid[NR_CPUS];
149 EXPORT_SYMBOL(ia64_cpu_to_sapicid);
150 
151 static volatile cpumask_t cpu_callin_map;
152 
153 struct smp_boot_data smp_boot_data __initdata;
154 
155 unsigned long ap_wakeup_vector = -1; /* External Int use to wakeup APs */
156 
157 char __initdata no_int_routing;
158 
159 unsigned char smp_int_redirect; /* are INT and IPI redirectable by the chipset? */
160 
161 #ifdef CONFIG_FORCE_CPEI_RETARGET
162 #define CPEI_OVERRIDE_DEFAULT	(1)
163 #else
164 #define CPEI_OVERRIDE_DEFAULT	(0)
165 #endif
166 
167 unsigned int force_cpei_retarget = CPEI_OVERRIDE_DEFAULT;
168 
169 static int __init
170 cmdl_force_cpei(char *str)
171 {
172 	int value=0;
173 
174 	get_option (&str, &value);
175 	force_cpei_retarget = value;
176 
177 	return 1;
178 }
179 
180 __setup("force_cpei=", cmdl_force_cpei);
181 
182 static int __init
183 nointroute (char *str)
184 {
185 	no_int_routing = 1;
186 	printk ("no_int_routing on\n");
187 	return 1;
188 }
189 
190 __setup("nointroute", nointroute);
191 
192 static void fix_b0_for_bsp(void)
193 {
194 #ifdef CONFIG_HOTPLUG_CPU
195 	int cpuid;
196 	static int fix_bsp_b0 = 1;
197 
198 	cpuid = smp_processor_id();
199 
200 	/*
201 	 * Cache the b0 value on the first AP that comes up
202 	 */
203 	if (!(fix_bsp_b0 && cpuid))
204 		return;
205 
206 	sal_boot_rendez_state[0].br[0] = sal_boot_rendez_state[cpuid].br[0];
207 	printk ("Fixed BSP b0 value from CPU %d\n", cpuid);
208 
209 	fix_bsp_b0 = 0;
210 #endif
211 }
212 
213 void
214 sync_master (void *arg)
215 {
216 	unsigned long flags, i;
217 
218 	go[MASTER] = 0;
219 
220 	local_irq_save(flags);
221 	{
222 		for (i = 0; i < NUM_ROUNDS*NUM_ITERS; ++i) {
223 			while (!go[MASTER])
224 				cpu_relax();
225 			go[MASTER] = 0;
226 			go[SLAVE] = ia64_get_itc();
227 		}
228 	}
229 	local_irq_restore(flags);
230 }
231 
232 /*
233  * Return the number of cycles by which our itc differs from the itc on the master
234  * (time-keeper) CPU.  A positive number indicates our itc is ahead of the master,
235  * negative that it is behind.
236  */
237 static inline long
238 get_delta (long *rt, long *master)
239 {
240 	unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
241 	unsigned long tcenter, t0, t1, tm;
242 	long i;
243 
244 	for (i = 0; i < NUM_ITERS; ++i) {
245 		t0 = ia64_get_itc();
246 		go[MASTER] = 1;
247 		while (!(tm = go[SLAVE]))
248 			cpu_relax();
249 		go[SLAVE] = 0;
250 		t1 = ia64_get_itc();
251 
252 		if (t1 - t0 < best_t1 - best_t0)
253 			best_t0 = t0, best_t1 = t1, best_tm = tm;
254 	}
255 
256 	*rt = best_t1 - best_t0;
257 	*master = best_tm - best_t0;
258 
259 	/* average best_t0 and best_t1 without overflow: */
260 	tcenter = (best_t0/2 + best_t1/2);
261 	if (best_t0 % 2 + best_t1 % 2 == 2)
262 		++tcenter;
263 	return tcenter - best_tm;
264 }
265 
266 /*
267  * Synchronize ar.itc of the current (slave) CPU with the ar.itc of the MASTER CPU
268  * (normally the time-keeper CPU).  We use a closed loop to eliminate the possibility of
269  * unaccounted-for errors (such as getting a machine check in the middle of a calibration
270  * step).  The basic idea is for the slave to ask the master what itc value it has and to
271  * read its own itc before and after the master responds.  Each iteration gives us three
272  * timestamps:
273  *
274  *	slave		master
275  *
276  *	t0 ---\
277  *             ---\
278  *		   --->
279  *			tm
280  *		   /---
281  *	       /---
282  *	t1 <---
283  *
284  *
285  * The goal is to adjust the slave's ar.itc such that tm falls exactly half-way between t0
286  * and t1.  If we achieve this, the clocks are synchronized provided the interconnect
287  * between the slave and the master is symmetric.  Even if the interconnect were
288  * asymmetric, we would still know that the synchronization error is smaller than the
289  * roundtrip latency (t0 - t1).
290  *
291  * When the interconnect is quiet and symmetric, this lets us synchronize the itc to
292  * within one or two cycles.  However, we can only *guarantee* that the synchronization is
293  * accurate to within a round-trip time, which is typically in the range of several
294  * hundred cycles (e.g., ~500 cycles).  In practice, this means that the itc's are usually
295  * almost perfectly synchronized, but we shouldn't assume that the accuracy is much better
296  * than half a micro second or so.
297  */
298 void
299 ia64_sync_itc (unsigned int master)
300 {
301 	long i, delta, adj, adjust_latency = 0, done = 0;
302 	unsigned long flags, rt, master_time_stamp, bound;
303 #if DEBUG_ITC_SYNC
304 	struct {
305 		long rt;	/* roundtrip time */
306 		long master;	/* master's timestamp */
307 		long diff;	/* difference between midpoint and master's timestamp */
308 		long lat;	/* estimate of itc adjustment latency */
309 	} t[NUM_ROUNDS];
310 #endif
311 
312 	/*
313 	 * Make sure local timer ticks are disabled while we sync.  If
314 	 * they were enabled, we'd have to worry about nasty issues
315 	 * like setting the ITC ahead of (or a long time before) the
316 	 * next scheduled tick.
317 	 */
318 	BUG_ON((ia64_get_itv() & (1 << 16)) == 0);
319 
320 	go[MASTER] = 1;
321 
322 	if (smp_call_function_single(master, sync_master, NULL, 0) < 0) {
323 		printk(KERN_ERR "sync_itc: failed to get attention of CPU %u!\n", master);
324 		return;
325 	}
326 
327 	while (go[MASTER])
328 		cpu_relax();	/* wait for master to be ready */
329 
330 	spin_lock_irqsave(&itc_sync_lock, flags);
331 	{
332 		for (i = 0; i < NUM_ROUNDS; ++i) {
333 			delta = get_delta(&rt, &master_time_stamp);
334 			if (delta == 0) {
335 				done = 1;	/* let's lock on to this... */
336 				bound = rt;
337 			}
338 
339 			if (!done) {
340 				if (i > 0) {
341 					adjust_latency += -delta;
342 					adj = -delta + adjust_latency/4;
343 				} else
344 					adj = -delta;
345 
346 				ia64_set_itc(ia64_get_itc() + adj);
347 			}
348 #if DEBUG_ITC_SYNC
349 			t[i].rt = rt;
350 			t[i].master = master_time_stamp;
351 			t[i].diff = delta;
352 			t[i].lat = adjust_latency/4;
353 #endif
354 		}
355 	}
356 	spin_unlock_irqrestore(&itc_sync_lock, flags);
357 
358 #if DEBUG_ITC_SYNC
359 	for (i = 0; i < NUM_ROUNDS; ++i)
360 		printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
361 		       t[i].rt, t[i].master, t[i].diff, t[i].lat);
362 #endif
363 
364 	printk(KERN_INFO "CPU %d: synchronized ITC with CPU %u (last diff %ld cycles, "
365 	       "maxerr %lu cycles)\n", smp_processor_id(), master, delta, rt);
366 }
367 
368 /*
369  * Ideally sets up per-cpu profiling hooks.  Doesn't do much now...
370  */
371 static inline void __devinit
372 smp_setup_percpu_timer (void)
373 {
374 }
375 
376 static void __cpuinit
377 smp_callin (void)
378 {
379 	int cpuid, phys_id, itc_master;
380 	struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
381 	extern void ia64_init_itm(void);
382 	extern volatile int time_keeper_id;
383 
384 #ifdef CONFIG_PERFMON
385 	extern void pfm_init_percpu(void);
386 #endif
387 
388 	cpuid = smp_processor_id();
389 	phys_id = hard_smp_processor_id();
390 	itc_master = time_keeper_id;
391 
392 	if (cpu_online(cpuid)) {
393 		printk(KERN_ERR "huh, phys CPU#0x%x, CPU#0x%x already present??\n",
394 		       phys_id, cpuid);
395 		BUG();
396 	}
397 
398 	fix_b0_for_bsp();
399 
400 	ipi_call_lock_irq();
401 	spin_lock(&vector_lock);
402 	/* Setup the per cpu irq handling data structures */
403 	__setup_vector_irq(cpuid);
404 	notify_cpu_starting(cpuid);
405 	cpu_set(cpuid, cpu_online_map);
406 	per_cpu(cpu_state, cpuid) = CPU_ONLINE;
407 	spin_unlock(&vector_lock);
408 	ipi_call_unlock_irq();
409 
410 	smp_setup_percpu_timer();
411 
412 	ia64_mca_cmc_vector_setup();	/* Setup vector on AP */
413 
414 #ifdef CONFIG_PERFMON
415 	pfm_init_percpu();
416 #endif
417 
418 	local_irq_enable();
419 
420 	if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
421 		/*
422 		 * Synchronize the ITC with the BP.  Need to do this after irqs are
423 		 * enabled because ia64_sync_itc() calls smp_call_function_single(), which
424 		 * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
425 		 * local_bh_enable(), which bugs out if irqs are not enabled...
426 		 */
427 		Dprintk("Going to syncup ITC with ITC Master.\n");
428 		ia64_sync_itc(itc_master);
429 	}
430 
431 	/*
432 	 * Get our bogomips.
433 	 */
434 	ia64_init_itm();
435 
436 	/*
437 	 * Delay calibration can be skipped if new processor is identical to the
438 	 * previous processor.
439 	 */
440 	last_cpuinfo = cpu_data(cpuid - 1);
441 	this_cpuinfo = local_cpu_data;
442 	if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
443 	    last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
444 	    last_cpuinfo->features != this_cpuinfo->features ||
445 	    last_cpuinfo->revision != this_cpuinfo->revision ||
446 	    last_cpuinfo->family != this_cpuinfo->family ||
447 	    last_cpuinfo->archrev != this_cpuinfo->archrev ||
448 	    last_cpuinfo->model != this_cpuinfo->model)
449 		calibrate_delay();
450 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
451 
452 #ifdef CONFIG_IA32_SUPPORT
453 	ia32_gdt_init();
454 #endif
455 
456 	/*
457 	 * Allow the master to continue.
458 	 */
459 	cpu_set(cpuid, cpu_callin_map);
460 	Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
461 }
462 
463 
464 /*
465  * Activate a secondary processor.  head.S calls this.
466  */
467 int __cpuinit
468 start_secondary (void *unused)
469 {
470 	/* Early console may use I/O ports */
471 	ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
472 #ifndef CONFIG_PRINTK_TIME
473 	Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
474 #endif
475 	efi_map_pal_code();
476 	cpu_init();
477 	preempt_disable();
478 	smp_callin();
479 
480 	cpu_idle();
481 	return 0;
482 }
483 
484 struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
485 {
486 	return NULL;
487 }
488 
489 struct create_idle {
490 	struct work_struct work;
491 	struct task_struct *idle;
492 	struct completion done;
493 	int cpu;
494 };
495 
496 void __cpuinit
497 do_fork_idle(struct work_struct *work)
498 {
499 	struct create_idle *c_idle =
500 		container_of(work, struct create_idle, work);
501 
502 	c_idle->idle = fork_idle(c_idle->cpu);
503 	complete(&c_idle->done);
504 }
505 
506 static int __cpuinit
507 do_boot_cpu (int sapicid, int cpu)
508 {
509 	int timeout;
510 	struct create_idle c_idle = {
511 		.work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
512 		.cpu	= cpu,
513 		.done	= COMPLETION_INITIALIZER(c_idle.done),
514 	};
515 
516  	c_idle.idle = get_idle_for_cpu(cpu);
517  	if (c_idle.idle) {
518 		init_idle(c_idle.idle, cpu);
519  		goto do_rest;
520 	}
521 
522 	/*
523 	 * We can't use kernel_thread since we must avoid to reschedule the child.
524 	 */
525 	if (!keventd_up() || current_is_keventd())
526 		c_idle.work.func(&c_idle.work);
527 	else {
528 		schedule_work(&c_idle.work);
529 		wait_for_completion(&c_idle.done);
530 	}
531 
532 	if (IS_ERR(c_idle.idle))
533 		panic("failed fork for CPU %d", cpu);
534 
535 	set_idle_for_cpu(cpu, c_idle.idle);
536 
537 do_rest:
538 	task_for_booting_cpu = c_idle.idle;
539 
540 	Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
541 
542 	set_brendez_area(cpu);
543 	platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
544 
545 	/*
546 	 * Wait 10s total for the AP to start
547 	 */
548 	Dprintk("Waiting on callin_map ...");
549 	for (timeout = 0; timeout < 100000; timeout++) {
550 		if (cpu_isset(cpu, cpu_callin_map))
551 			break;  /* It has booted */
552 		udelay(100);
553 	}
554 	Dprintk("\n");
555 
556 	if (!cpu_isset(cpu, cpu_callin_map)) {
557 		printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
558 		ia64_cpu_to_sapicid[cpu] = -1;
559 		cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
560 		return -EINVAL;
561 	}
562 	return 0;
563 }
564 
565 static int __init
566 decay (char *str)
567 {
568 	int ticks;
569 	get_option (&str, &ticks);
570 	return 1;
571 }
572 
573 __setup("decay=", decay);
574 
575 /*
576  * Initialize the logical CPU number to SAPICID mapping
577  */
578 void __init
579 smp_build_cpu_map (void)
580 {
581 	int sapicid, cpu, i;
582 	int boot_cpu_id = hard_smp_processor_id();
583 
584 	for (cpu = 0; cpu < NR_CPUS; cpu++) {
585 		ia64_cpu_to_sapicid[cpu] = -1;
586 	}
587 
588 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
589 	cpus_clear(cpu_present_map);
590 	cpu_set(0, cpu_present_map);
591 	cpu_set(0, cpu_possible_map);
592 	for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
593 		sapicid = smp_boot_data.cpu_phys_id[i];
594 		if (sapicid == boot_cpu_id)
595 			continue;
596 		cpu_set(cpu, cpu_present_map);
597 		cpu_set(cpu, cpu_possible_map);
598 		ia64_cpu_to_sapicid[cpu] = sapicid;
599 		cpu++;
600 	}
601 }
602 
603 /*
604  * Cycle through the APs sending Wakeup IPIs to boot each.
605  */
606 void __init
607 smp_prepare_cpus (unsigned int max_cpus)
608 {
609 	int boot_cpu_id = hard_smp_processor_id();
610 
611 	/*
612 	 * Initialize the per-CPU profiling counter/multiplier
613 	 */
614 
615 	smp_setup_percpu_timer();
616 
617 	/*
618 	 * We have the boot CPU online for sure.
619 	 */
620 	cpu_set(0, cpu_online_map);
621 	cpu_set(0, cpu_callin_map);
622 
623 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
624 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
625 
626 	printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
627 
628 	current_thread_info()->cpu = 0;
629 
630 	/*
631 	 * If SMP should be disabled, then really disable it!
632 	 */
633 	if (!max_cpus) {
634 		printk(KERN_INFO "SMP mode deactivated.\n");
635 		cpus_clear(cpu_online_map);
636 		cpus_clear(cpu_present_map);
637 		cpus_clear(cpu_possible_map);
638 		cpu_set(0, cpu_online_map);
639 		cpu_set(0, cpu_present_map);
640 		cpu_set(0, cpu_possible_map);
641 		return;
642 	}
643 }
644 
645 void __devinit smp_prepare_boot_cpu(void)
646 {
647 	cpu_set(smp_processor_id(), cpu_online_map);
648 	cpu_set(smp_processor_id(), cpu_callin_map);
649 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
650 	paravirt_post_smp_prepare_boot_cpu();
651 }
652 
653 #ifdef CONFIG_HOTPLUG_CPU
654 static inline void
655 clear_cpu_sibling_map(int cpu)
656 {
657 	int i;
658 
659 	for_each_cpu_mask(i, per_cpu(cpu_sibling_map, cpu))
660 		cpu_clear(cpu, per_cpu(cpu_sibling_map, i));
661 	for_each_cpu_mask(i, cpu_core_map[cpu])
662 		cpu_clear(cpu, cpu_core_map[i]);
663 
664 	per_cpu(cpu_sibling_map, cpu) = cpu_core_map[cpu] = CPU_MASK_NONE;
665 }
666 
667 static void
668 remove_siblinginfo(int cpu)
669 {
670 	int last = 0;
671 
672 	if (cpu_data(cpu)->threads_per_core == 1 &&
673 	    cpu_data(cpu)->cores_per_socket == 1) {
674 		cpu_clear(cpu, cpu_core_map[cpu]);
675 		cpu_clear(cpu, per_cpu(cpu_sibling_map, cpu));
676 		return;
677 	}
678 
679 	last = (cpus_weight(cpu_core_map[cpu]) == 1 ? 1 : 0);
680 
681 	/* remove it from all sibling map's */
682 	clear_cpu_sibling_map(cpu);
683 }
684 
685 extern void fixup_irqs(void);
686 
687 int migrate_platform_irqs(unsigned int cpu)
688 {
689 	int new_cpei_cpu;
690 	irq_desc_t *desc = NULL;
691 	cpumask_t 	mask;
692 	int 		retval = 0;
693 
694 	/*
695 	 * dont permit CPEI target to removed.
696 	 */
697 	if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
698 		printk ("CPU (%d) is CPEI Target\n", cpu);
699 		if (can_cpei_retarget()) {
700 			/*
701 			 * Now re-target the CPEI to a different processor
702 			 */
703 			new_cpei_cpu = any_online_cpu(cpu_online_map);
704 			mask = cpumask_of_cpu(new_cpei_cpu);
705 			set_cpei_target_cpu(new_cpei_cpu);
706 			desc = irq_desc + ia64_cpe_irq;
707 			/*
708 			 * Switch for now, immediately, we need to do fake intr
709 			 * as other interrupts, but need to study CPEI behaviour with
710 			 * polling before making changes.
711 			 */
712 			if (desc) {
713 				desc->chip->disable(ia64_cpe_irq);
714 				desc->chip->set_affinity(ia64_cpe_irq, mask);
715 				desc->chip->enable(ia64_cpe_irq);
716 				printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
717 			}
718 		}
719 		if (!desc) {
720 			printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
721 			retval = -EBUSY;
722 		}
723 	}
724 	return retval;
725 }
726 
727 /* must be called with cpucontrol mutex held */
728 int __cpu_disable(void)
729 {
730 	int cpu = smp_processor_id();
731 
732 	/*
733 	 * dont permit boot processor for now
734 	 */
735 	if (cpu == 0 && !bsp_remove_ok) {
736 		printk ("Your platform does not support removal of BSP\n");
737 		return (-EBUSY);
738 	}
739 
740 	if (ia64_platform_is("sn2")) {
741 		if (!sn_cpu_disable_allowed(cpu))
742 			return -EBUSY;
743 	}
744 
745 	if (migrate_platform_irqs(cpu)) {
746 		cpu_set(cpu, cpu_online_map);
747 		return (-EBUSY);
748 	}
749 
750 	remove_siblinginfo(cpu);
751 	fixup_irqs();
752 	cpu_clear(cpu, cpu_online_map);
753 	local_flush_tlb_all();
754 	cpu_clear(cpu, cpu_callin_map);
755 	return 0;
756 }
757 
758 void __cpu_die(unsigned int cpu)
759 {
760 	unsigned int i;
761 
762 	for (i = 0; i < 100; i++) {
763 		/* They ack this in play_dead by setting CPU_DEAD */
764 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
765 		{
766 			printk ("CPU %d is now offline\n", cpu);
767 			return;
768 		}
769 		msleep(100);
770 	}
771  	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
772 }
773 #endif /* CONFIG_HOTPLUG_CPU */
774 
775 void
776 smp_cpus_done (unsigned int dummy)
777 {
778 	int cpu;
779 	unsigned long bogosum = 0;
780 
781 	/*
782 	 * Allow the user to impress friends.
783 	 */
784 
785 	for_each_online_cpu(cpu) {
786 		bogosum += cpu_data(cpu)->loops_per_jiffy;
787 	}
788 
789 	printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
790 	       (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
791 }
792 
793 static inline void __devinit
794 set_cpu_sibling_map(int cpu)
795 {
796 	int i;
797 
798 	for_each_online_cpu(i) {
799 		if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
800 			cpu_set(i, cpu_core_map[cpu]);
801 			cpu_set(cpu, cpu_core_map[i]);
802 			if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
803 				cpu_set(i, per_cpu(cpu_sibling_map, cpu));
804 				cpu_set(cpu, per_cpu(cpu_sibling_map, i));
805 			}
806 		}
807 	}
808 }
809 
810 int __cpuinit
811 __cpu_up (unsigned int cpu)
812 {
813 	int ret;
814 	int sapicid;
815 
816 	sapicid = ia64_cpu_to_sapicid[cpu];
817 	if (sapicid == -1)
818 		return -EINVAL;
819 
820 	/*
821 	 * Already booted cpu? not valid anymore since we dont
822 	 * do idle loop tightspin anymore.
823 	 */
824 	if (cpu_isset(cpu, cpu_callin_map))
825 		return -EINVAL;
826 
827 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
828 	/* Processor goes to start_secondary(), sets online flag */
829 	ret = do_boot_cpu(sapicid, cpu);
830 	if (ret < 0)
831 		return ret;
832 
833 	if (cpu_data(cpu)->threads_per_core == 1 &&
834 	    cpu_data(cpu)->cores_per_socket == 1) {
835 		cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
836 		cpu_set(cpu, cpu_core_map[cpu]);
837 		return 0;
838 	}
839 
840 	set_cpu_sibling_map(cpu);
841 
842 	return 0;
843 }
844 
845 /*
846  * Assume that CPUs have been discovered by some platform-dependent interface.  For
847  * SoftSDV/Lion, that would be ACPI.
848  *
849  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
850  */
851 void __init
852 init_smp_config(void)
853 {
854 	struct fptr {
855 		unsigned long fp;
856 		unsigned long gp;
857 	} *ap_startup;
858 	long sal_ret;
859 
860 	/* Tell SAL where to drop the APs.  */
861 	ap_startup = (struct fptr *) start_ap;
862 	sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
863 				       ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
864 	if (sal_ret < 0)
865 		printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
866 		       ia64_sal_strerror(sal_ret));
867 }
868 
869 /*
870  * identify_siblings(cpu) gets called from identify_cpu. This populates the
871  * information related to logical execution units in per_cpu_data structure.
872  */
873 void __devinit
874 identify_siblings(struct cpuinfo_ia64 *c)
875 {
876 	s64 status;
877 	u16 pltid;
878 	pal_logical_to_physical_t info;
879 
880 	status = ia64_pal_logical_to_phys(-1, &info);
881 	if (status != PAL_STATUS_SUCCESS) {
882 		if (status != PAL_STATUS_UNIMPLEMENTED) {
883 			printk(KERN_ERR
884 				"ia64_pal_logical_to_phys failed with %ld\n",
885 				status);
886 			return;
887 		}
888 
889 		info.overview_ppid = 0;
890 		info.overview_cpp  = 1;
891 		info.overview_tpc  = 1;
892 	}
893 
894 	status = ia64_sal_physical_id_info(&pltid);
895 	if (status != PAL_STATUS_SUCCESS) {
896 		if (status != PAL_STATUS_UNIMPLEMENTED)
897 			printk(KERN_ERR
898 				"ia64_sal_pltid failed with %ld\n",
899 				status);
900 		return;
901 	}
902 
903 	c->socket_id =  (pltid << 8) | info.overview_ppid;
904 
905 	if (info.overview_cpp == 1 && info.overview_tpc == 1)
906 		return;
907 
908 	c->cores_per_socket = info.overview_cpp;
909 	c->threads_per_core = info.overview_tpc;
910 	c->num_log = info.overview_num_log;
911 
912 	c->core_id = info.log1_cid;
913 	c->thread_id = info.log1_tid;
914 }
915 
916 /*
917  * returns non zero, if multi-threading is enabled
918  * on at least one physical package. Due to hotplug cpu
919  * and (maxcpus=), all threads may not necessarily be enabled
920  * even though the processor supports multi-threading.
921  */
922 int is_multithreading_enabled(void)
923 {
924 	int i, j;
925 
926 	for_each_present_cpu(i) {
927 		for_each_present_cpu(j) {
928 			if (j == i)
929 				continue;
930 			if ((cpu_data(j)->socket_id == cpu_data(i)->socket_id)) {
931 				if (cpu_data(j)->core_id == cpu_data(i)->core_id)
932 					return 1;
933 			}
934 		}
935 	}
936 	return 0;
937 }
938 EXPORT_SYMBOL_GPL(is_multithreading_enabled);
939