xref: /openbmc/linux/arch/ia64/kernel/smpboot.c (revision c21b37f6)
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 __cpuinit
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 	spin_lock(&vector_lock);
399 	/* Setup the per cpu irq handling data structures */
400 	__setup_vector_irq(cpuid);
401 	cpu_set(cpuid, cpu_online_map);
402 	unlock_ipi_calllock();
403 	per_cpu(cpu_state, cpuid) = CPU_ONLINE;
404 	spin_unlock(&vector_lock);
405 
406 	smp_setup_percpu_timer();
407 
408 	ia64_mca_cmc_vector_setup();	/* Setup vector on AP */
409 
410 #ifdef CONFIG_PERFMON
411 	pfm_init_percpu();
412 #endif
413 
414 	local_irq_enable();
415 
416 	if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
417 		/*
418 		 * Synchronize the ITC with the BP.  Need to do this after irqs are
419 		 * enabled because ia64_sync_itc() calls smp_call_function_single(), which
420 		 * calls spin_unlock_bh(), which calls spin_unlock_bh(), which calls
421 		 * local_bh_enable(), which bugs out if irqs are not enabled...
422 		 */
423 		Dprintk("Going to syncup ITC with ITC Master.\n");
424 		ia64_sync_itc(itc_master);
425 	}
426 
427 	/*
428 	 * Get our bogomips.
429 	 */
430 	ia64_init_itm();
431 
432 	/*
433 	 * Delay calibration can be skipped if new processor is identical to the
434 	 * previous processor.
435 	 */
436 	last_cpuinfo = cpu_data(cpuid - 1);
437 	this_cpuinfo = local_cpu_data;
438 	if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
439 	    last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
440 	    last_cpuinfo->features != this_cpuinfo->features ||
441 	    last_cpuinfo->revision != this_cpuinfo->revision ||
442 	    last_cpuinfo->family != this_cpuinfo->family ||
443 	    last_cpuinfo->archrev != this_cpuinfo->archrev ||
444 	    last_cpuinfo->model != this_cpuinfo->model)
445 		calibrate_delay();
446 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
447 
448 #ifdef CONFIG_IA32_SUPPORT
449 	ia32_gdt_init();
450 #endif
451 
452 	/*
453 	 * Allow the master to continue.
454 	 */
455 	cpu_set(cpuid, cpu_callin_map);
456 	Dprintk("Stack on CPU %d at about %p\n",cpuid, &cpuid);
457 }
458 
459 
460 /*
461  * Activate a secondary processor.  head.S calls this.
462  */
463 int __cpuinit
464 start_secondary (void *unused)
465 {
466 	/* Early console may use I/O ports */
467 	ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
468 	Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
469 	efi_map_pal_code();
470 	cpu_init();
471 	preempt_disable();
472 	smp_callin();
473 
474 	cpu_idle();
475 	return 0;
476 }
477 
478 struct pt_regs * __devinit idle_regs(struct pt_regs *regs)
479 {
480 	return NULL;
481 }
482 
483 struct create_idle {
484 	struct work_struct work;
485 	struct task_struct *idle;
486 	struct completion done;
487 	int cpu;
488 };
489 
490 void __cpuinit
491 do_fork_idle(struct work_struct *work)
492 {
493 	struct create_idle *c_idle =
494 		container_of(work, struct create_idle, work);
495 
496 	c_idle->idle = fork_idle(c_idle->cpu);
497 	complete(&c_idle->done);
498 }
499 
500 static int __cpuinit
501 do_boot_cpu (int sapicid, int cpu)
502 {
503 	int timeout;
504 	struct create_idle c_idle = {
505 		.work = __WORK_INITIALIZER(c_idle.work, do_fork_idle),
506 		.cpu	= cpu,
507 		.done	= COMPLETION_INITIALIZER(c_idle.done),
508 	};
509 
510  	c_idle.idle = get_idle_for_cpu(cpu);
511  	if (c_idle.idle) {
512 		init_idle(c_idle.idle, cpu);
513  		goto do_rest;
514 	}
515 
516 	/*
517 	 * We can't use kernel_thread since we must avoid to reschedule the child.
518 	 */
519 	if (!keventd_up() || current_is_keventd())
520 		c_idle.work.func(&c_idle.work);
521 	else {
522 		schedule_work(&c_idle.work);
523 		wait_for_completion(&c_idle.done);
524 	}
525 
526 	if (IS_ERR(c_idle.idle))
527 		panic("failed fork for CPU %d", cpu);
528 
529 	set_idle_for_cpu(cpu, c_idle.idle);
530 
531 do_rest:
532 	task_for_booting_cpu = c_idle.idle;
533 
534 	Dprintk("Sending wakeup vector %lu to AP 0x%x/0x%x.\n", ap_wakeup_vector, cpu, sapicid);
535 
536 	set_brendez_area(cpu);
537 	platform_send_ipi(cpu, ap_wakeup_vector, IA64_IPI_DM_INT, 0);
538 
539 	/*
540 	 * Wait 10s total for the AP to start
541 	 */
542 	Dprintk("Waiting on callin_map ...");
543 	for (timeout = 0; timeout < 100000; timeout++) {
544 		if (cpu_isset(cpu, cpu_callin_map))
545 			break;  /* It has booted */
546 		udelay(100);
547 	}
548 	Dprintk("\n");
549 
550 	if (!cpu_isset(cpu, cpu_callin_map)) {
551 		printk(KERN_ERR "Processor 0x%x/0x%x is stuck.\n", cpu, sapicid);
552 		ia64_cpu_to_sapicid[cpu] = -1;
553 		cpu_clear(cpu, cpu_online_map);  /* was set in smp_callin() */
554 		return -EINVAL;
555 	}
556 	return 0;
557 }
558 
559 static int __init
560 decay (char *str)
561 {
562 	int ticks;
563 	get_option (&str, &ticks);
564 	return 1;
565 }
566 
567 __setup("decay=", decay);
568 
569 /*
570  * Initialize the logical CPU number to SAPICID mapping
571  */
572 void __init
573 smp_build_cpu_map (void)
574 {
575 	int sapicid, cpu, i;
576 	int boot_cpu_id = hard_smp_processor_id();
577 
578 	for (cpu = 0; cpu < NR_CPUS; cpu++) {
579 		ia64_cpu_to_sapicid[cpu] = -1;
580 	}
581 
582 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
583 	cpus_clear(cpu_present_map);
584 	cpu_set(0, cpu_present_map);
585 	cpu_set(0, cpu_possible_map);
586 	for (cpu = 1, i = 0; i < smp_boot_data.cpu_count; i++) {
587 		sapicid = smp_boot_data.cpu_phys_id[i];
588 		if (sapicid == boot_cpu_id)
589 			continue;
590 		cpu_set(cpu, cpu_present_map);
591 		cpu_set(cpu, cpu_possible_map);
592 		ia64_cpu_to_sapicid[cpu] = sapicid;
593 		cpu++;
594 	}
595 }
596 
597 /*
598  * Cycle through the APs sending Wakeup IPIs to boot each.
599  */
600 void __init
601 smp_prepare_cpus (unsigned int max_cpus)
602 {
603 	int boot_cpu_id = hard_smp_processor_id();
604 
605 	/*
606 	 * Initialize the per-CPU profiling counter/multiplier
607 	 */
608 
609 	smp_setup_percpu_timer();
610 
611 	/*
612 	 * We have the boot CPU online for sure.
613 	 */
614 	cpu_set(0, cpu_online_map);
615 	cpu_set(0, cpu_callin_map);
616 
617 	local_cpu_data->loops_per_jiffy = loops_per_jiffy;
618 	ia64_cpu_to_sapicid[0] = boot_cpu_id;
619 
620 	printk(KERN_INFO "Boot processor id 0x%x/0x%x\n", 0, boot_cpu_id);
621 
622 	current_thread_info()->cpu = 0;
623 
624 	/*
625 	 * If SMP should be disabled, then really disable it!
626 	 */
627 	if (!max_cpus) {
628 		printk(KERN_INFO "SMP mode deactivated.\n");
629 		cpus_clear(cpu_online_map);
630 		cpus_clear(cpu_present_map);
631 		cpus_clear(cpu_possible_map);
632 		cpu_set(0, cpu_online_map);
633 		cpu_set(0, cpu_present_map);
634 		cpu_set(0, cpu_possible_map);
635 		return;
636 	}
637 }
638 
639 void __devinit smp_prepare_boot_cpu(void)
640 {
641 	cpu_set(smp_processor_id(), cpu_online_map);
642 	cpu_set(smp_processor_id(), cpu_callin_map);
643 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
644 }
645 
646 #ifdef CONFIG_HOTPLUG_CPU
647 static inline void
648 clear_cpu_sibling_map(int cpu)
649 {
650 	int i;
651 
652 	for_each_cpu_mask(i, cpu_sibling_map[cpu])
653 		cpu_clear(cpu, cpu_sibling_map[i]);
654 	for_each_cpu_mask(i, cpu_core_map[cpu])
655 		cpu_clear(cpu, cpu_core_map[i]);
656 
657 	cpu_sibling_map[cpu] = cpu_core_map[cpu] = CPU_MASK_NONE;
658 }
659 
660 static void
661 remove_siblinginfo(int cpu)
662 {
663 	int last = 0;
664 
665 	if (cpu_data(cpu)->threads_per_core == 1 &&
666 	    cpu_data(cpu)->cores_per_socket == 1) {
667 		cpu_clear(cpu, cpu_core_map[cpu]);
668 		cpu_clear(cpu, cpu_sibling_map[cpu]);
669 		return;
670 	}
671 
672 	last = (cpus_weight(cpu_core_map[cpu]) == 1 ? 1 : 0);
673 
674 	/* remove it from all sibling map's */
675 	clear_cpu_sibling_map(cpu);
676 }
677 
678 extern void fixup_irqs(void);
679 
680 int migrate_platform_irqs(unsigned int cpu)
681 {
682 	int new_cpei_cpu;
683 	irq_desc_t *desc = NULL;
684 	cpumask_t 	mask;
685 	int 		retval = 0;
686 
687 	/*
688 	 * dont permit CPEI target to removed.
689 	 */
690 	if (cpe_vector > 0 && is_cpu_cpei_target(cpu)) {
691 		printk ("CPU (%d) is CPEI Target\n", cpu);
692 		if (can_cpei_retarget()) {
693 			/*
694 			 * Now re-target the CPEI to a different processor
695 			 */
696 			new_cpei_cpu = any_online_cpu(cpu_online_map);
697 			mask = cpumask_of_cpu(new_cpei_cpu);
698 			set_cpei_target_cpu(new_cpei_cpu);
699 			desc = irq_desc + ia64_cpe_irq;
700 			/*
701 			 * Switch for now, immediately, we need to do fake intr
702 			 * as other interrupts, but need to study CPEI behaviour with
703 			 * polling before making changes.
704 			 */
705 			if (desc) {
706 				desc->chip->disable(ia64_cpe_irq);
707 				desc->chip->set_affinity(ia64_cpe_irq, mask);
708 				desc->chip->enable(ia64_cpe_irq);
709 				printk ("Re-targetting CPEI to cpu %d\n", new_cpei_cpu);
710 			}
711 		}
712 		if (!desc) {
713 			printk ("Unable to retarget CPEI, offline cpu [%d] failed\n", cpu);
714 			retval = -EBUSY;
715 		}
716 	}
717 	return retval;
718 }
719 
720 /* must be called with cpucontrol mutex held */
721 int __cpu_disable(void)
722 {
723 	int cpu = smp_processor_id();
724 
725 	/*
726 	 * dont permit boot processor for now
727 	 */
728 	if (cpu == 0 && !bsp_remove_ok) {
729 		printk ("Your platform does not support removal of BSP\n");
730 		return (-EBUSY);
731 	}
732 
733 	cpu_clear(cpu, cpu_online_map);
734 
735 	if (migrate_platform_irqs(cpu)) {
736 		cpu_set(cpu, cpu_online_map);
737 		return (-EBUSY);
738 	}
739 
740 	remove_siblinginfo(cpu);
741 	cpu_clear(cpu, cpu_online_map);
742 	fixup_irqs();
743 	local_flush_tlb_all();
744 	cpu_clear(cpu, cpu_callin_map);
745 	return 0;
746 }
747 
748 void __cpu_die(unsigned int cpu)
749 {
750 	unsigned int i;
751 
752 	for (i = 0; i < 100; i++) {
753 		/* They ack this in play_dead by setting CPU_DEAD */
754 		if (per_cpu(cpu_state, cpu) == CPU_DEAD)
755 		{
756 			printk ("CPU %d is now offline\n", cpu);
757 			return;
758 		}
759 		msleep(100);
760 	}
761  	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
762 }
763 #else /* !CONFIG_HOTPLUG_CPU */
764 int __cpu_disable(void)
765 {
766 	return -ENOSYS;
767 }
768 
769 void __cpu_die(unsigned int cpu)
770 {
771 	/* We said "no" in __cpu_disable */
772 	BUG();
773 }
774 #endif /* CONFIG_HOTPLUG_CPU */
775 
776 void
777 smp_cpus_done (unsigned int dummy)
778 {
779 	int cpu;
780 	unsigned long bogosum = 0;
781 
782 	/*
783 	 * Allow the user to impress friends.
784 	 */
785 
786 	for_each_online_cpu(cpu) {
787 		bogosum += cpu_data(cpu)->loops_per_jiffy;
788 	}
789 
790 	printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
791 	       (int)num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100);
792 }
793 
794 static inline void __devinit
795 set_cpu_sibling_map(int cpu)
796 {
797 	int i;
798 
799 	for_each_online_cpu(i) {
800 		if ((cpu_data(cpu)->socket_id == cpu_data(i)->socket_id)) {
801 			cpu_set(i, cpu_core_map[cpu]);
802 			cpu_set(cpu, cpu_core_map[i]);
803 			if (cpu_data(cpu)->core_id == cpu_data(i)->core_id) {
804 				cpu_set(i, cpu_sibling_map[cpu]);
805 				cpu_set(cpu, cpu_sibling_map[i]);
806 			}
807 		}
808 	}
809 }
810 
811 int __cpuinit
812 __cpu_up (unsigned int cpu)
813 {
814 	int ret;
815 	int sapicid;
816 
817 	sapicid = ia64_cpu_to_sapicid[cpu];
818 	if (sapicid == -1)
819 		return -EINVAL;
820 
821 	/*
822 	 * Already booted cpu? not valid anymore since we dont
823 	 * do idle loop tightspin anymore.
824 	 */
825 	if (cpu_isset(cpu, cpu_callin_map))
826 		return -EINVAL;
827 
828 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
829 	/* Processor goes to start_secondary(), sets online flag */
830 	ret = do_boot_cpu(sapicid, cpu);
831 	if (ret < 0)
832 		return ret;
833 
834 	if (cpu_data(cpu)->threads_per_core == 1 &&
835 	    cpu_data(cpu)->cores_per_socket == 1) {
836 		cpu_set(cpu, cpu_sibling_map[cpu]);
837 		cpu_set(cpu, cpu_core_map[cpu]);
838 		return 0;
839 	}
840 
841 	set_cpu_sibling_map(cpu);
842 
843 	return 0;
844 }
845 
846 /*
847  * Assume that CPUs have been discovered by some platform-dependent interface.  For
848  * SoftSDV/Lion, that would be ACPI.
849  *
850  * Setup of the IPI irq handler is done in irq.c:init_IRQ_SMP().
851  */
852 void __init
853 init_smp_config(void)
854 {
855 	struct fptr {
856 		unsigned long fp;
857 		unsigned long gp;
858 	} *ap_startup;
859 	long sal_ret;
860 
861 	/* Tell SAL where to drop the APs.  */
862 	ap_startup = (struct fptr *) start_ap;
863 	sal_ret = ia64_sal_set_vectors(SAL_VECTOR_OS_BOOT_RENDEZ,
864 				       ia64_tpa(ap_startup->fp), ia64_tpa(ap_startup->gp), 0, 0, 0, 0);
865 	if (sal_ret < 0)
866 		printk(KERN_ERR "SMP: Can't set SAL AP Boot Rendezvous: %s\n",
867 		       ia64_sal_strerror(sal_ret));
868 }
869 
870 /*
871  * identify_siblings(cpu) gets called from identify_cpu. This populates the
872  * information related to logical execution units in per_cpu_data structure.
873  */
874 void __devinit
875 identify_siblings(struct cpuinfo_ia64 *c)
876 {
877 	s64 status;
878 	u16 pltid;
879 	pal_logical_to_physical_t info;
880 
881 	if (smp_num_cpucores == 1 && smp_num_siblings == 1)
882 		return;
883 
884 	if ((status = ia64_pal_logical_to_phys(-1, &info)) != PAL_STATUS_SUCCESS) {
885 		printk(KERN_ERR "ia64_pal_logical_to_phys failed with %ld\n",
886 		       status);
887 		return;
888 	}
889 	if ((status = ia64_sal_physical_id_info(&pltid)) != PAL_STATUS_SUCCESS) {
890 		printk(KERN_ERR "ia64_sal_pltid failed with %ld\n", status);
891 		return;
892 	}
893 
894 	c->socket_id =  (pltid << 8) | info.overview_ppid;
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);
926