xref: /linux/arch/x86/kernel/smpboot.c (revision 5499b45190237ca90dd2ac86395cf464fe1f4cc7)
1 /*
2  *	x86 SMP booting functions
3  *
4  *	(c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
5  *	(c) 1998, 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
6  *	Copyright 2001 Andi Kleen, SuSE Labs.
7  *
8  *	Much of the core SMP work is based on previous work by Thomas Radke, to
9  *	whom a great many thanks are extended.
10  *
11  *	Thanks to Intel for making available several different Pentium,
12  *	Pentium Pro and Pentium-II/Xeon MP machines.
13  *	Original development of Linux SMP code supported by Caldera.
14  *
15  *	This code is released under the GNU General Public License version 2 or
16  *	later.
17  *
18  *	Fixes
19  *		Felix Koop	:	NR_CPUS used properly
20  *		Jose Renau	:	Handle single CPU case.
21  *		Alan Cox	:	By repeated request 8) - Total BogoMIPS report.
22  *		Greg Wright	:	Fix for kernel stacks panic.
23  *		Erich Boleyn	:	MP v1.4 and additional changes.
24  *	Matthias Sattler	:	Changes for 2.1 kernel map.
25  *	Michel Lespinasse	:	Changes for 2.1 kernel map.
26  *	Michael Chastain	:	Change trampoline.S to gnu as.
27  *		Alan Cox	:	Dumb bug: 'B' step PPro's are fine
28  *		Ingo Molnar	:	Added APIC timers, based on code
29  *					from Jose Renau
30  *		Ingo Molnar	:	various cleanups and rewrites
31  *		Tigran Aivazian	:	fixed "0.00 in /proc/uptime on SMP" bug.
32  *	Maciej W. Rozycki	:	Bits for genuine 82489DX APICs
33  *	Andi Kleen		:	Changed for SMP boot into long mode.
34  *		Martin J. Bligh	: 	Added support for multi-quad systems
35  *		Dave Jones	:	Report invalid combinations of Athlon CPUs.
36  *		Rusty Russell	:	Hacked into shape for new "hotplug" boot process.
37  *      Andi Kleen              :       Converted to new state machine.
38  *	Ashok Raj		: 	CPU hotplug support
39  *	Glauber Costa		:	i386 and x86_64 integration
40  */
41 
42 #include <linux/init.h>
43 #include <linux/smp.h>
44 #include <linux/module.h>
45 #include <linux/sched.h>
46 #include <linux/percpu.h>
47 #include <linux/bootmem.h>
48 #include <linux/err.h>
49 #include <linux/nmi.h>
50 #include <linux/tboot.h>
51 
52 #include <asm/acpi.h>
53 #include <asm/desc.h>
54 #include <asm/nmi.h>
55 #include <asm/irq.h>
56 #include <asm/idle.h>
57 #include <asm/trampoline.h>
58 #include <asm/cpu.h>
59 #include <asm/numa.h>
60 #include <asm/pgtable.h>
61 #include <asm/tlbflush.h>
62 #include <asm/mtrr.h>
63 #include <asm/vmi.h>
64 #include <asm/apic.h>
65 #include <asm/setup.h>
66 #include <asm/uv/uv.h>
67 #include <linux/mc146818rtc.h>
68 
69 #include <asm/smpboot_hooks.h>
70 
71 #ifdef CONFIG_X86_32
72 u8 apicid_2_node[MAX_APICID];
73 static int low_mappings;
74 #endif
75 
76 /* State of each CPU */
77 DEFINE_PER_CPU(int, cpu_state) = { 0 };
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 #ifdef CONFIG_HOTPLUG_CPU
84 /*
85  * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
86  * removed after init for !CONFIG_HOTPLUG_CPU.
87  */
88 static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
89 #define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
90 #define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
91 #else
92 static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
93 #define get_idle_for_cpu(x)      (idle_thread_array[(x)])
94 #define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
95 #endif
96 
97 /* Number of siblings per CPU package */
98 int smp_num_siblings = 1;
99 EXPORT_SYMBOL(smp_num_siblings);
100 
101 /* Last level cache ID of each logical CPU */
102 DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID;
103 
104 /* representing HT siblings of each logical CPU */
105 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
106 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
107 
108 /* representing HT and core siblings of each logical CPU */
109 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
110 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
111 
112 /* Per CPU bogomips and other parameters */
113 DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
114 EXPORT_PER_CPU_SYMBOL(cpu_info);
115 
116 atomic_t init_deasserted;
117 
118 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_32)
119 /* which node each logical CPU is on */
120 int cpu_to_node_map[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 };
121 EXPORT_SYMBOL(cpu_to_node_map);
122 
123 /* set up a mapping between cpu and node. */
124 static void map_cpu_to_node(int cpu, int node)
125 {
126 	printk(KERN_INFO "Mapping cpu %d to node %d\n", cpu, node);
127 	cpumask_set_cpu(cpu, node_to_cpumask_map[node]);
128 	cpu_to_node_map[cpu] = node;
129 }
130 
131 /* undo a mapping between cpu and node. */
132 static void unmap_cpu_to_node(int cpu)
133 {
134 	int node;
135 
136 	printk(KERN_INFO "Unmapping cpu %d from all nodes\n", cpu);
137 	for (node = 0; node < MAX_NUMNODES; node++)
138 		cpumask_clear_cpu(cpu, node_to_cpumask_map[node]);
139 	cpu_to_node_map[cpu] = 0;
140 }
141 #else /* !(CONFIG_NUMA && CONFIG_X86_32) */
142 #define map_cpu_to_node(cpu, node)	({})
143 #define unmap_cpu_to_node(cpu)	({})
144 #endif
145 
146 #ifdef CONFIG_X86_32
147 static int boot_cpu_logical_apicid;
148 
149 u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly =
150 					{ [0 ... NR_CPUS-1] = BAD_APICID };
151 
152 static void map_cpu_to_logical_apicid(void)
153 {
154 	int cpu = smp_processor_id();
155 	int apicid = logical_smp_processor_id();
156 	int node = apic->apicid_to_node(apicid);
157 
158 	if (!node_online(node))
159 		node = first_online_node;
160 
161 	cpu_2_logical_apicid[cpu] = apicid;
162 	map_cpu_to_node(cpu, node);
163 }
164 
165 void numa_remove_cpu(int cpu)
166 {
167 	cpu_2_logical_apicid[cpu] = BAD_APICID;
168 	unmap_cpu_to_node(cpu);
169 }
170 #else
171 #define map_cpu_to_logical_apicid()  do {} while (0)
172 #endif
173 
174 /*
175  * Report back to the Boot Processor.
176  * Running on AP.
177  */
178 static void __cpuinit smp_callin(void)
179 {
180 	int cpuid, phys_id;
181 	unsigned long timeout;
182 
183 	/*
184 	 * If waken up by an INIT in an 82489DX configuration
185 	 * we may get here before an INIT-deassert IPI reaches
186 	 * our local APIC.  We have to wait for the IPI or we'll
187 	 * lock up on an APIC access.
188 	 */
189 	if (apic->wait_for_init_deassert)
190 		apic->wait_for_init_deassert(&init_deasserted);
191 
192 	/*
193 	 * (This works even if the APIC is not enabled.)
194 	 */
195 	phys_id = read_apic_id();
196 	cpuid = smp_processor_id();
197 	if (cpumask_test_cpu(cpuid, cpu_callin_mask)) {
198 		panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
199 					phys_id, cpuid);
200 	}
201 	pr_debug("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
202 
203 	/*
204 	 * STARTUP IPIs are fragile beasts as they might sometimes
205 	 * trigger some glue motherboard logic. Complete APIC bus
206 	 * silence for 1 second, this overestimates the time the
207 	 * boot CPU is spending to send the up to 2 STARTUP IPIs
208 	 * by a factor of two. This should be enough.
209 	 */
210 
211 	/*
212 	 * Waiting 2s total for startup (udelay is not yet working)
213 	 */
214 	timeout = jiffies + 2*HZ;
215 	while (time_before(jiffies, timeout)) {
216 		/*
217 		 * Has the boot CPU finished it's STARTUP sequence?
218 		 */
219 		if (cpumask_test_cpu(cpuid, cpu_callout_mask))
220 			break;
221 		cpu_relax();
222 	}
223 
224 	if (!time_before(jiffies, timeout)) {
225 		panic("%s: CPU%d started up but did not get a callout!\n",
226 		      __func__, cpuid);
227 	}
228 
229 	/*
230 	 * the boot CPU has finished the init stage and is spinning
231 	 * on callin_map until we finish. We are free to set up this
232 	 * CPU, first the APIC. (this is probably redundant on most
233 	 * boards)
234 	 */
235 
236 	pr_debug("CALLIN, before setup_local_APIC().\n");
237 	if (apic->smp_callin_clear_local_apic)
238 		apic->smp_callin_clear_local_apic();
239 	setup_local_APIC();
240 	end_local_APIC_setup();
241 	map_cpu_to_logical_apicid();
242 
243 	notify_cpu_starting(cpuid);
244 	/*
245 	 * Get our bogomips.
246 	 *
247 	 * Need to enable IRQs because it can take longer and then
248 	 * the NMI watchdog might kill us.
249 	 */
250 	local_irq_enable();
251 	calibrate_delay();
252 	local_irq_disable();
253 	pr_debug("Stack at about %p\n", &cpuid);
254 
255 	/*
256 	 * Save our processor parameters
257 	 */
258 	smp_store_cpu_info(cpuid);
259 
260 	/*
261 	 * Allow the master to continue.
262 	 */
263 	cpumask_set_cpu(cpuid, cpu_callin_mask);
264 }
265 
266 /*
267  * Activate a secondary processor.
268  */
269 notrace static void __cpuinit start_secondary(void *unused)
270 {
271 	/*
272 	 * Don't put *anything* before cpu_init(), SMP booting is too
273 	 * fragile that we want to limit the things done here to the
274 	 * most necessary things.
275 	 */
276 	vmi_bringup();
277 	cpu_init();
278 	preempt_disable();
279 	smp_callin();
280 
281 	/* otherwise gcc will move up smp_processor_id before the cpu_init */
282 	barrier();
283 	/*
284 	 * Check TSC synchronization with the BP:
285 	 */
286 	check_tsc_sync_target();
287 
288 	if (nmi_watchdog == NMI_IO_APIC) {
289 		disable_8259A_irq(0);
290 		enable_NMI_through_LVT0();
291 		enable_8259A_irq(0);
292 	}
293 
294 #ifdef CONFIG_X86_32
295 	while (low_mappings)
296 		cpu_relax();
297 	__flush_tlb_all();
298 #endif
299 
300 	/* This must be done before setting cpu_online_mask */
301 	set_cpu_sibling_map(raw_smp_processor_id());
302 	wmb();
303 
304 	/*
305 	 * We need to hold call_lock, so there is no inconsistency
306 	 * between the time smp_call_function() determines number of
307 	 * IPI recipients, and the time when the determination is made
308 	 * for which cpus receive the IPI. Holding this
309 	 * lock helps us to not include this cpu in a currently in progress
310 	 * smp_call_function().
311 	 *
312 	 * We need to hold vector_lock so there the set of online cpus
313 	 * does not change while we are assigning vectors to cpus.  Holding
314 	 * this lock ensures we don't half assign or remove an irq from a cpu.
315 	 */
316 	ipi_call_lock();
317 	lock_vector_lock();
318 	__setup_vector_irq(smp_processor_id());
319 	set_cpu_online(smp_processor_id(), true);
320 	unlock_vector_lock();
321 	ipi_call_unlock();
322 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
323 	x86_platform.nmi_init();
324 
325 	/* enable local interrupts */
326 	local_irq_enable();
327 
328 	x86_cpuinit.setup_percpu_clockev();
329 
330 	wmb();
331 	cpu_idle();
332 }
333 
334 #ifdef CONFIG_CPUMASK_OFFSTACK
335 /* In this case, llc_shared_map is a pointer to a cpumask. */
336 static inline void copy_cpuinfo_x86(struct cpuinfo_x86 *dst,
337 				    const struct cpuinfo_x86 *src)
338 {
339 	struct cpumask *llc = dst->llc_shared_map;
340 	*dst = *src;
341 	dst->llc_shared_map = llc;
342 }
343 #else
344 static inline void copy_cpuinfo_x86(struct cpuinfo_x86 *dst,
345 				    const struct cpuinfo_x86 *src)
346 {
347 	*dst = *src;
348 }
349 #endif /* CONFIG_CPUMASK_OFFSTACK */
350 
351 /*
352  * The bootstrap kernel entry code has set these up. Save them for
353  * a given CPU
354  */
355 
356 void __cpuinit smp_store_cpu_info(int id)
357 {
358 	struct cpuinfo_x86 *c = &cpu_data(id);
359 
360 	copy_cpuinfo_x86(c, &boot_cpu_data);
361 	c->cpu_index = id;
362 	if (id != 0)
363 		identify_secondary_cpu(c);
364 }
365 
366 
367 void __cpuinit set_cpu_sibling_map(int cpu)
368 {
369 	int i;
370 	struct cpuinfo_x86 *c = &cpu_data(cpu);
371 
372 	cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
373 
374 	if (smp_num_siblings > 1) {
375 		for_each_cpu(i, cpu_sibling_setup_mask) {
376 			struct cpuinfo_x86 *o = &cpu_data(i);
377 
378 			if (c->phys_proc_id == o->phys_proc_id &&
379 			    c->cpu_core_id == o->cpu_core_id) {
380 				cpumask_set_cpu(i, cpu_sibling_mask(cpu));
381 				cpumask_set_cpu(cpu, cpu_sibling_mask(i));
382 				cpumask_set_cpu(i, cpu_core_mask(cpu));
383 				cpumask_set_cpu(cpu, cpu_core_mask(i));
384 				cpumask_set_cpu(i, c->llc_shared_map);
385 				cpumask_set_cpu(cpu, o->llc_shared_map);
386 			}
387 		}
388 	} else {
389 		cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
390 	}
391 
392 	cpumask_set_cpu(cpu, c->llc_shared_map);
393 
394 	if (current_cpu_data.x86_max_cores == 1) {
395 		cpumask_copy(cpu_core_mask(cpu), cpu_sibling_mask(cpu));
396 		c->booted_cores = 1;
397 		return;
398 	}
399 
400 	for_each_cpu(i, cpu_sibling_setup_mask) {
401 		if (per_cpu(cpu_llc_id, cpu) != BAD_APICID &&
402 		    per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) {
403 			cpumask_set_cpu(i, c->llc_shared_map);
404 			cpumask_set_cpu(cpu, cpu_data(i).llc_shared_map);
405 		}
406 		if (c->phys_proc_id == cpu_data(i).phys_proc_id) {
407 			cpumask_set_cpu(i, cpu_core_mask(cpu));
408 			cpumask_set_cpu(cpu, cpu_core_mask(i));
409 			/*
410 			 *  Does this new cpu bringup a new core?
411 			 */
412 			if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) {
413 				/*
414 				 * for each core in package, increment
415 				 * the booted_cores for this new cpu
416 				 */
417 				if (cpumask_first(cpu_sibling_mask(i)) == i)
418 					c->booted_cores++;
419 				/*
420 				 * increment the core count for all
421 				 * the other cpus in this package
422 				 */
423 				if (i != cpu)
424 					cpu_data(i).booted_cores++;
425 			} else if (i != cpu && !c->booted_cores)
426 				c->booted_cores = cpu_data(i).booted_cores;
427 		}
428 	}
429 }
430 
431 /* maps the cpu to the sched domain representing multi-core */
432 const struct cpumask *cpu_coregroup_mask(int cpu)
433 {
434 	struct cpuinfo_x86 *c = &cpu_data(cpu);
435 	/*
436 	 * For perf, we return last level cache shared map.
437 	 * And for power savings, we return cpu_core_map
438 	 */
439 	if ((sched_mc_power_savings || sched_smt_power_savings) &&
440 	    !(cpu_has(c, X86_FEATURE_AMD_DCM)))
441 		return cpu_core_mask(cpu);
442 	else
443 		return c->llc_shared_map;
444 }
445 
446 static void impress_friends(void)
447 {
448 	int cpu;
449 	unsigned long bogosum = 0;
450 	/*
451 	 * Allow the user to impress friends.
452 	 */
453 	pr_debug("Before bogomips.\n");
454 	for_each_possible_cpu(cpu)
455 		if (cpumask_test_cpu(cpu, cpu_callout_mask))
456 			bogosum += cpu_data(cpu).loops_per_jiffy;
457 	printk(KERN_INFO
458 		"Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
459 		num_online_cpus(),
460 		bogosum/(500000/HZ),
461 		(bogosum/(5000/HZ))%100);
462 
463 	pr_debug("Before bogocount - setting activated=1.\n");
464 }
465 
466 void __inquire_remote_apic(int apicid)
467 {
468 	unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
469 	char *names[] = { "ID", "VERSION", "SPIV" };
470 	int timeout;
471 	u32 status;
472 
473 	printk(KERN_INFO "Inquiring remote APIC 0x%x...\n", apicid);
474 
475 	for (i = 0; i < ARRAY_SIZE(regs); i++) {
476 		printk(KERN_INFO "... APIC 0x%x %s: ", apicid, names[i]);
477 
478 		/*
479 		 * Wait for idle.
480 		 */
481 		status = safe_apic_wait_icr_idle();
482 		if (status)
483 			printk(KERN_CONT
484 			       "a previous APIC delivery may have failed\n");
485 
486 		apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
487 
488 		timeout = 0;
489 		do {
490 			udelay(100);
491 			status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
492 		} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
493 
494 		switch (status) {
495 		case APIC_ICR_RR_VALID:
496 			status = apic_read(APIC_RRR);
497 			printk(KERN_CONT "%08x\n", status);
498 			break;
499 		default:
500 			printk(KERN_CONT "failed\n");
501 		}
502 	}
503 }
504 
505 /*
506  * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
507  * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
508  * won't ... remember to clear down the APIC, etc later.
509  */
510 int __cpuinit
511 wakeup_secondary_cpu_via_nmi(int logical_apicid, unsigned long start_eip)
512 {
513 	unsigned long send_status, accept_status = 0;
514 	int maxlvt;
515 
516 	/* Target chip */
517 	/* Boot on the stack */
518 	/* Kick the second */
519 	apic_icr_write(APIC_DM_NMI | apic->dest_logical, logical_apicid);
520 
521 	pr_debug("Waiting for send to finish...\n");
522 	send_status = safe_apic_wait_icr_idle();
523 
524 	/*
525 	 * Give the other CPU some time to accept the IPI.
526 	 */
527 	udelay(200);
528 	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
529 		maxlvt = lapic_get_maxlvt();
530 		if (maxlvt > 3)			/* Due to the Pentium erratum 3AP.  */
531 			apic_write(APIC_ESR, 0);
532 		accept_status = (apic_read(APIC_ESR) & 0xEF);
533 	}
534 	pr_debug("NMI sent.\n");
535 
536 	if (send_status)
537 		printk(KERN_ERR "APIC never delivered???\n");
538 	if (accept_status)
539 		printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
540 
541 	return (send_status | accept_status);
542 }
543 
544 static int __cpuinit
545 wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
546 {
547 	unsigned long send_status, accept_status = 0;
548 	int maxlvt, num_starts, j;
549 
550 	maxlvt = lapic_get_maxlvt();
551 
552 	/*
553 	 * Be paranoid about clearing APIC errors.
554 	 */
555 	if (APIC_INTEGRATED(apic_version[phys_apicid])) {
556 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
557 			apic_write(APIC_ESR, 0);
558 		apic_read(APIC_ESR);
559 	}
560 
561 	pr_debug("Asserting INIT.\n");
562 
563 	/*
564 	 * Turn INIT on target chip
565 	 */
566 	/*
567 	 * Send IPI
568 	 */
569 	apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
570 		       phys_apicid);
571 
572 	pr_debug("Waiting for send to finish...\n");
573 	send_status = safe_apic_wait_icr_idle();
574 
575 	mdelay(10);
576 
577 	pr_debug("Deasserting INIT.\n");
578 
579 	/* Target chip */
580 	/* Send IPI */
581 	apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
582 
583 	pr_debug("Waiting for send to finish...\n");
584 	send_status = safe_apic_wait_icr_idle();
585 
586 	mb();
587 	atomic_set(&init_deasserted, 1);
588 
589 	/*
590 	 * Should we send STARTUP IPIs ?
591 	 *
592 	 * Determine this based on the APIC version.
593 	 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
594 	 */
595 	if (APIC_INTEGRATED(apic_version[phys_apicid]))
596 		num_starts = 2;
597 	else
598 		num_starts = 0;
599 
600 	/*
601 	 * Paravirt / VMI wants a startup IPI hook here to set up the
602 	 * target processor state.
603 	 */
604 	startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
605 			 (unsigned long)stack_start.sp);
606 
607 	/*
608 	 * Run STARTUP IPI loop.
609 	 */
610 	pr_debug("#startup loops: %d.\n", num_starts);
611 
612 	for (j = 1; j <= num_starts; j++) {
613 		pr_debug("Sending STARTUP #%d.\n", j);
614 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
615 			apic_write(APIC_ESR, 0);
616 		apic_read(APIC_ESR);
617 		pr_debug("After apic_write.\n");
618 
619 		/*
620 		 * STARTUP IPI
621 		 */
622 
623 		/* Target chip */
624 		/* Boot on the stack */
625 		/* Kick the second */
626 		apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
627 			       phys_apicid);
628 
629 		/*
630 		 * Give the other CPU some time to accept the IPI.
631 		 */
632 		udelay(300);
633 
634 		pr_debug("Startup point 1.\n");
635 
636 		pr_debug("Waiting for send to finish...\n");
637 		send_status = safe_apic_wait_icr_idle();
638 
639 		/*
640 		 * Give the other CPU some time to accept the IPI.
641 		 */
642 		udelay(200);
643 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
644 			apic_write(APIC_ESR, 0);
645 		accept_status = (apic_read(APIC_ESR) & 0xEF);
646 		if (send_status || accept_status)
647 			break;
648 	}
649 	pr_debug("After Startup.\n");
650 
651 	if (send_status)
652 		printk(KERN_ERR "APIC never delivered???\n");
653 	if (accept_status)
654 		printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
655 
656 	return (send_status | accept_status);
657 }
658 
659 struct create_idle {
660 	struct work_struct work;
661 	struct task_struct *idle;
662 	struct completion done;
663 	int cpu;
664 };
665 
666 static void __cpuinit do_fork_idle(struct work_struct *work)
667 {
668 	struct create_idle *c_idle =
669 		container_of(work, struct create_idle, work);
670 
671 	c_idle->idle = fork_idle(c_idle->cpu);
672 	complete(&c_idle->done);
673 }
674 
675 /* reduce the number of lines printed when booting a large cpu count system */
676 static void __cpuinit announce_cpu(int cpu, int apicid)
677 {
678 	static int current_node = -1;
679 	int node = cpu_to_node(cpu);
680 
681 	if (system_state == SYSTEM_BOOTING) {
682 		if (node != current_node) {
683 			if (current_node > (-1))
684 				pr_cont(" Ok.\n");
685 			current_node = node;
686 			pr_info("Booting Node %3d, Processors ", node);
687 		}
688 		pr_cont(" #%d%s", cpu, cpu == (nr_cpu_ids - 1) ? " Ok.\n" : "");
689 		return;
690 	} else
691 		pr_info("Booting Node %d Processor %d APIC 0x%x\n",
692 			node, cpu, apicid);
693 }
694 
695 /*
696  * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
697  * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
698  * Returns zero if CPU booted OK, else error code from
699  * ->wakeup_secondary_cpu.
700  */
701 static int __cpuinit do_boot_cpu(int apicid, int cpu)
702 {
703 	unsigned long boot_error = 0;
704 	unsigned long start_ip;
705 	int timeout;
706 	struct create_idle c_idle = {
707 		.cpu	= cpu,
708 		.done	= COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
709 	};
710 
711 	INIT_WORK_ON_STACK(&c_idle.work, do_fork_idle);
712 
713 	alternatives_smp_switch(1);
714 
715 	c_idle.idle = get_idle_for_cpu(cpu);
716 
717 	/*
718 	 * We can't use kernel_thread since we must avoid to
719 	 * reschedule the child.
720 	 */
721 	if (c_idle.idle) {
722 		c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
723 			(THREAD_SIZE +  task_stack_page(c_idle.idle))) - 1);
724 		init_idle(c_idle.idle, cpu);
725 		goto do_rest;
726 	}
727 
728 	if (!keventd_up() || current_is_keventd())
729 		c_idle.work.func(&c_idle.work);
730 	else {
731 		schedule_work(&c_idle.work);
732 		wait_for_completion(&c_idle.done);
733 	}
734 
735 	if (IS_ERR(c_idle.idle)) {
736 		printk("failed fork for CPU %d\n", cpu);
737 		destroy_work_on_stack(&c_idle.work);
738 		return PTR_ERR(c_idle.idle);
739 	}
740 
741 	set_idle_for_cpu(cpu, c_idle.idle);
742 do_rest:
743 	per_cpu(current_task, cpu) = c_idle.idle;
744 #ifdef CONFIG_X86_32
745 	/* Stack for startup_32 can be just as for start_secondary onwards */
746 	irq_ctx_init(cpu);
747 #else
748 	clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
749 	initial_gs = per_cpu_offset(cpu);
750 	per_cpu(kernel_stack, cpu) =
751 		(unsigned long)task_stack_page(c_idle.idle) -
752 		KERNEL_STACK_OFFSET + THREAD_SIZE;
753 #endif
754 	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
755 	initial_code = (unsigned long)start_secondary;
756 	stack_start.sp = (void *) c_idle.idle->thread.sp;
757 
758 	/* start_ip had better be page-aligned! */
759 	start_ip = setup_trampoline();
760 
761 	/* So we see what's up */
762 	announce_cpu(cpu, apicid);
763 
764 	/*
765 	 * This grunge runs the startup process for
766 	 * the targeted processor.
767 	 */
768 
769 	atomic_set(&init_deasserted, 0);
770 
771 	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
772 
773 		pr_debug("Setting warm reset code and vector.\n");
774 
775 		smpboot_setup_warm_reset_vector(start_ip);
776 		/*
777 		 * Be paranoid about clearing APIC errors.
778 		*/
779 		if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
780 			apic_write(APIC_ESR, 0);
781 			apic_read(APIC_ESR);
782 		}
783 	}
784 
785 	/*
786 	 * Kick the secondary CPU. Use the method in the APIC driver
787 	 * if it's defined - or use an INIT boot APIC message otherwise:
788 	 */
789 	if (apic->wakeup_secondary_cpu)
790 		boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
791 	else
792 		boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
793 
794 	if (!boot_error) {
795 		/*
796 		 * allow APs to start initializing.
797 		 */
798 		pr_debug("Before Callout %d.\n", cpu);
799 		cpumask_set_cpu(cpu, cpu_callout_mask);
800 		pr_debug("After Callout %d.\n", cpu);
801 
802 		/*
803 		 * Wait 5s total for a response
804 		 */
805 		for (timeout = 0; timeout < 50000; timeout++) {
806 			if (cpumask_test_cpu(cpu, cpu_callin_mask))
807 				break;	/* It has booted */
808 			udelay(100);
809 		}
810 
811 		if (cpumask_test_cpu(cpu, cpu_callin_mask))
812 			pr_debug("CPU%d: has booted.\n", cpu);
813 		else {
814 			boot_error = 1;
815 			if (*((volatile unsigned char *)trampoline_base)
816 					== 0xA5)
817 				/* trampoline started but...? */
818 				pr_err("CPU%d: Stuck ??\n", cpu);
819 			else
820 				/* trampoline code not run */
821 				pr_err("CPU%d: Not responding.\n", cpu);
822 			if (apic->inquire_remote_apic)
823 				apic->inquire_remote_apic(apicid);
824 		}
825 	}
826 
827 	if (boot_error) {
828 		/* Try to put things back the way they were before ... */
829 		numa_remove_cpu(cpu); /* was set by numa_add_cpu */
830 
831 		/* was set by do_boot_cpu() */
832 		cpumask_clear_cpu(cpu, cpu_callout_mask);
833 
834 		/* was set by cpu_init() */
835 		cpumask_clear_cpu(cpu, cpu_initialized_mask);
836 
837 		set_cpu_present(cpu, false);
838 		per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
839 	}
840 
841 	/* mark "stuck" area as not stuck */
842 	*((volatile unsigned long *)trampoline_base) = 0;
843 
844 	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
845 		/*
846 		 * Cleanup possible dangling ends...
847 		 */
848 		smpboot_restore_warm_reset_vector();
849 	}
850 
851 	destroy_work_on_stack(&c_idle.work);
852 	return boot_error;
853 }
854 
855 int __cpuinit native_cpu_up(unsigned int cpu)
856 {
857 	int apicid = apic->cpu_present_to_apicid(cpu);
858 	unsigned long flags;
859 	int err;
860 
861 	WARN_ON(irqs_disabled());
862 
863 	pr_debug("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
864 
865 	if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid ||
866 	    !physid_isset(apicid, phys_cpu_present_map)) {
867 		printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu);
868 		return -EINVAL;
869 	}
870 
871 	/*
872 	 * Already booted CPU?
873 	 */
874 	if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
875 		pr_debug("do_boot_cpu %d Already started\n", cpu);
876 		return -ENOSYS;
877 	}
878 
879 	/*
880 	 * Save current MTRR state in case it was changed since early boot
881 	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
882 	 */
883 	mtrr_save_state();
884 
885 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
886 
887 #ifdef CONFIG_X86_32
888 	/* init low mem mapping */
889 	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
890 		min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
891 	flush_tlb_all();
892 	low_mappings = 1;
893 
894 	err = do_boot_cpu(apicid, cpu);
895 
896 	zap_low_mappings(false);
897 	low_mappings = 0;
898 #else
899 	err = do_boot_cpu(apicid, cpu);
900 #endif
901 	if (err) {
902 		pr_debug("do_boot_cpu failed %d\n", err);
903 		return -EIO;
904 	}
905 
906 	/*
907 	 * Check TSC synchronization with the AP (keep irqs disabled
908 	 * while doing so):
909 	 */
910 	local_irq_save(flags);
911 	check_tsc_sync_source(cpu);
912 	local_irq_restore(flags);
913 
914 	while (!cpu_online(cpu)) {
915 		cpu_relax();
916 		touch_nmi_watchdog();
917 	}
918 
919 	return 0;
920 }
921 
922 /*
923  * Fall back to non SMP mode after errors.
924  *
925  * RED-PEN audit/test this more. I bet there is more state messed up here.
926  */
927 static __init void disable_smp(void)
928 {
929 	init_cpu_present(cpumask_of(0));
930 	init_cpu_possible(cpumask_of(0));
931 	smpboot_clear_io_apic_irqs();
932 
933 	if (smp_found_config)
934 		physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
935 	else
936 		physid_set_mask_of_physid(0, &phys_cpu_present_map);
937 	map_cpu_to_logical_apicid();
938 	cpumask_set_cpu(0, cpu_sibling_mask(0));
939 	cpumask_set_cpu(0, cpu_core_mask(0));
940 }
941 
942 /*
943  * Various sanity checks.
944  */
945 static int __init smp_sanity_check(unsigned max_cpus)
946 {
947 	preempt_disable();
948 
949 #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
950 	if (def_to_bigsmp && nr_cpu_ids > 8) {
951 		unsigned int cpu;
952 		unsigned nr;
953 
954 		printk(KERN_WARNING
955 		       "More than 8 CPUs detected - skipping them.\n"
956 		       "Use CONFIG_X86_BIGSMP.\n");
957 
958 		nr = 0;
959 		for_each_present_cpu(cpu) {
960 			if (nr >= 8)
961 				set_cpu_present(cpu, false);
962 			nr++;
963 		}
964 
965 		nr = 0;
966 		for_each_possible_cpu(cpu) {
967 			if (nr >= 8)
968 				set_cpu_possible(cpu, false);
969 			nr++;
970 		}
971 
972 		nr_cpu_ids = 8;
973 	}
974 #endif
975 
976 	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
977 		printk(KERN_WARNING
978 			"weird, boot CPU (#%d) not listed by the BIOS.\n",
979 			hard_smp_processor_id());
980 
981 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
982 	}
983 
984 	/*
985 	 * If we couldn't find an SMP configuration at boot time,
986 	 * get out of here now!
987 	 */
988 	if (!smp_found_config && !acpi_lapic) {
989 		preempt_enable();
990 		printk(KERN_NOTICE "SMP motherboard not detected.\n");
991 		disable_smp();
992 		if (APIC_init_uniprocessor())
993 			printk(KERN_NOTICE "Local APIC not detected."
994 					   " Using dummy APIC emulation.\n");
995 		return -1;
996 	}
997 
998 	/*
999 	 * Should not be necessary because the MP table should list the boot
1000 	 * CPU too, but we do it for the sake of robustness anyway.
1001 	 */
1002 	if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
1003 		printk(KERN_NOTICE
1004 			"weird, boot CPU (#%d) not listed by the BIOS.\n",
1005 			boot_cpu_physical_apicid);
1006 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
1007 	}
1008 	preempt_enable();
1009 
1010 	/*
1011 	 * If we couldn't find a local APIC, then get out of here now!
1012 	 */
1013 	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
1014 	    !cpu_has_apic) {
1015 		if (!disable_apic) {
1016 			pr_err("BIOS bug, local APIC #%d not detected!...\n",
1017 				boot_cpu_physical_apicid);
1018 			pr_err("... forcing use of dummy APIC emulation."
1019 				"(tell your hw vendor)\n");
1020 		}
1021 		smpboot_clear_io_apic();
1022 		arch_disable_smp_support();
1023 		return -1;
1024 	}
1025 
1026 	verify_local_APIC();
1027 
1028 	/*
1029 	 * If SMP should be disabled, then really disable it!
1030 	 */
1031 	if (!max_cpus) {
1032 		printk(KERN_INFO "SMP mode deactivated.\n");
1033 		smpboot_clear_io_apic();
1034 
1035 		localise_nmi_watchdog();
1036 
1037 		connect_bsp_APIC();
1038 		setup_local_APIC();
1039 		end_local_APIC_setup();
1040 		return -1;
1041 	}
1042 
1043 	return 0;
1044 }
1045 
1046 static void __init smp_cpu_index_default(void)
1047 {
1048 	int i;
1049 	struct cpuinfo_x86 *c;
1050 
1051 	for_each_possible_cpu(i) {
1052 		c = &cpu_data(i);
1053 		/* mark all to hotplug */
1054 		c->cpu_index = nr_cpu_ids;
1055 	}
1056 }
1057 
1058 /*
1059  * Prepare for SMP bootup.  The MP table or ACPI has been read
1060  * earlier.  Just do some sanity checking here and enable APIC mode.
1061  */
1062 void __init native_smp_prepare_cpus(unsigned int max_cpus)
1063 {
1064 	unsigned int i;
1065 
1066 	preempt_disable();
1067 	smp_cpu_index_default();
1068 	current_cpu_data = boot_cpu_data;
1069 	cpumask_copy(cpu_callin_mask, cpumask_of(0));
1070 	mb();
1071 	/*
1072 	 * Setup boot CPU information
1073 	 */
1074 	smp_store_cpu_info(0); /* Final full version of the data */
1075 #ifdef CONFIG_X86_32
1076 	boot_cpu_logical_apicid = logical_smp_processor_id();
1077 #endif
1078 	current_thread_info()->cpu = 0;  /* needed? */
1079 	for_each_possible_cpu(i) {
1080 		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
1081 		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
1082 		zalloc_cpumask_var(&cpu_data(i).llc_shared_map, GFP_KERNEL);
1083 	}
1084 	set_cpu_sibling_map(0);
1085 
1086 	enable_IR_x2apic();
1087 	default_setup_apic_routing();
1088 
1089 	if (smp_sanity_check(max_cpus) < 0) {
1090 		printk(KERN_INFO "SMP disabled\n");
1091 		disable_smp();
1092 		goto out;
1093 	}
1094 
1095 	preempt_disable();
1096 	if (read_apic_id() != boot_cpu_physical_apicid) {
1097 		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
1098 		     read_apic_id(), boot_cpu_physical_apicid);
1099 		/* Or can we switch back to PIC here? */
1100 	}
1101 	preempt_enable();
1102 
1103 	connect_bsp_APIC();
1104 
1105 	/*
1106 	 * Switch from PIC to APIC mode.
1107 	 */
1108 	setup_local_APIC();
1109 
1110 	/*
1111 	 * Enable IO APIC before setting up error vector
1112 	 */
1113 	if (!skip_ioapic_setup && nr_ioapics)
1114 		enable_IO_APIC();
1115 
1116 	end_local_APIC_setup();
1117 
1118 	map_cpu_to_logical_apicid();
1119 
1120 	if (apic->setup_portio_remap)
1121 		apic->setup_portio_remap();
1122 
1123 	smpboot_setup_io_apic();
1124 	/*
1125 	 * Set up local APIC timer on boot CPU.
1126 	 */
1127 
1128 	printk(KERN_INFO "CPU%d: ", 0);
1129 	print_cpu_info(&cpu_data(0));
1130 	x86_init.timers.setup_percpu_clockev();
1131 
1132 	if (is_uv_system())
1133 		uv_system_init();
1134 
1135 	set_mtrr_aps_delayed_init();
1136 out:
1137 	preempt_enable();
1138 }
1139 
1140 void arch_enable_nonboot_cpus_begin(void)
1141 {
1142 	set_mtrr_aps_delayed_init();
1143 }
1144 
1145 void arch_enable_nonboot_cpus_end(void)
1146 {
1147 	mtrr_aps_init();
1148 }
1149 
1150 /*
1151  * Early setup to make printk work.
1152  */
1153 void __init native_smp_prepare_boot_cpu(void)
1154 {
1155 	int me = smp_processor_id();
1156 	switch_to_new_gdt(me);
1157 	/* already set me in cpu_online_mask in boot_cpu_init() */
1158 	cpumask_set_cpu(me, cpu_callout_mask);
1159 	per_cpu(cpu_state, me) = CPU_ONLINE;
1160 }
1161 
1162 void __init native_smp_cpus_done(unsigned int max_cpus)
1163 {
1164 	pr_debug("Boot done.\n");
1165 
1166 	impress_friends();
1167 #ifdef CONFIG_X86_IO_APIC
1168 	setup_ioapic_dest();
1169 #endif
1170 	check_nmi_watchdog();
1171 	mtrr_aps_init();
1172 }
1173 
1174 static int __initdata setup_possible_cpus = -1;
1175 static int __init _setup_possible_cpus(char *str)
1176 {
1177 	get_option(&str, &setup_possible_cpus);
1178 	return 0;
1179 }
1180 early_param("possible_cpus", _setup_possible_cpus);
1181 
1182 
1183 /*
1184  * cpu_possible_mask should be static, it cannot change as cpu's
1185  * are onlined, or offlined. The reason is per-cpu data-structures
1186  * are allocated by some modules at init time, and dont expect to
1187  * do this dynamically on cpu arrival/departure.
1188  * cpu_present_mask on the other hand can change dynamically.
1189  * In case when cpu_hotplug is not compiled, then we resort to current
1190  * behaviour, which is cpu_possible == cpu_present.
1191  * - Ashok Raj
1192  *
1193  * Three ways to find out the number of additional hotplug CPUs:
1194  * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
1195  * - The user can overwrite it with possible_cpus=NUM
1196  * - Otherwise don't reserve additional CPUs.
1197  * We do this because additional CPUs waste a lot of memory.
1198  * -AK
1199  */
1200 __init void prefill_possible_map(void)
1201 {
1202 	int i, possible;
1203 
1204 	/* no processor from mptable or madt */
1205 	if (!num_processors)
1206 		num_processors = 1;
1207 
1208 	if (setup_possible_cpus == -1)
1209 		possible = num_processors + disabled_cpus;
1210 	else
1211 		possible = setup_possible_cpus;
1212 
1213 	total_cpus = max_t(int, possible, num_processors + disabled_cpus);
1214 
1215 	if (possible > CONFIG_NR_CPUS) {
1216 		printk(KERN_WARNING
1217 			"%d Processors exceeds NR_CPUS limit of %d\n",
1218 			possible, CONFIG_NR_CPUS);
1219 		possible = CONFIG_NR_CPUS;
1220 	}
1221 
1222 	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
1223 		possible, max_t(int, possible - num_processors, 0));
1224 
1225 	for (i = 0; i < possible; i++)
1226 		set_cpu_possible(i, true);
1227 
1228 	nr_cpu_ids = possible;
1229 }
1230 
1231 #ifdef CONFIG_HOTPLUG_CPU
1232 
1233 static void remove_siblinginfo(int cpu)
1234 {
1235 	int sibling;
1236 	struct cpuinfo_x86 *c = &cpu_data(cpu);
1237 
1238 	for_each_cpu(sibling, cpu_core_mask(cpu)) {
1239 		cpumask_clear_cpu(cpu, cpu_core_mask(sibling));
1240 		/*/
1241 		 * last thread sibling in this cpu core going down
1242 		 */
1243 		if (cpumask_weight(cpu_sibling_mask(cpu)) == 1)
1244 			cpu_data(sibling).booted_cores--;
1245 	}
1246 
1247 	for_each_cpu(sibling, cpu_sibling_mask(cpu))
1248 		cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
1249 	cpumask_clear(cpu_sibling_mask(cpu));
1250 	cpumask_clear(cpu_core_mask(cpu));
1251 	c->phys_proc_id = 0;
1252 	c->cpu_core_id = 0;
1253 	cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
1254 }
1255 
1256 static void __ref remove_cpu_from_maps(int cpu)
1257 {
1258 	set_cpu_online(cpu, false);
1259 	cpumask_clear_cpu(cpu, cpu_callout_mask);
1260 	cpumask_clear_cpu(cpu, cpu_callin_mask);
1261 	/* was set by cpu_init() */
1262 	cpumask_clear_cpu(cpu, cpu_initialized_mask);
1263 	numa_remove_cpu(cpu);
1264 }
1265 
1266 void cpu_disable_common(void)
1267 {
1268 	int cpu = smp_processor_id();
1269 
1270 	remove_siblinginfo(cpu);
1271 
1272 	/* It's now safe to remove this processor from the online map */
1273 	lock_vector_lock();
1274 	remove_cpu_from_maps(cpu);
1275 	unlock_vector_lock();
1276 	fixup_irqs();
1277 }
1278 
1279 int native_cpu_disable(void)
1280 {
1281 	int cpu = smp_processor_id();
1282 
1283 	/*
1284 	 * Perhaps use cpufreq to drop frequency, but that could go
1285 	 * into generic code.
1286 	 *
1287 	 * We won't take down the boot processor on i386 due to some
1288 	 * interrupts only being able to be serviced by the BSP.
1289 	 * Especially so if we're not using an IOAPIC	-zwane
1290 	 */
1291 	if (cpu == 0)
1292 		return -EBUSY;
1293 
1294 	if (nmi_watchdog == NMI_LOCAL_APIC)
1295 		stop_apic_nmi_watchdog(NULL);
1296 	clear_local_APIC();
1297 
1298 	cpu_disable_common();
1299 	return 0;
1300 }
1301 
1302 void native_cpu_die(unsigned int cpu)
1303 {
1304 	/* We don't do anything here: idle task is faking death itself. */
1305 	unsigned int i;
1306 
1307 	for (i = 0; i < 10; i++) {
1308 		/* They ack this in play_dead by setting CPU_DEAD */
1309 		if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
1310 			if (system_state == SYSTEM_RUNNING)
1311 				pr_info("CPU %u is now offline\n", cpu);
1312 
1313 			if (1 == num_online_cpus())
1314 				alternatives_smp_switch(0);
1315 			return;
1316 		}
1317 		msleep(100);
1318 	}
1319 	pr_err("CPU %u didn't die...\n", cpu);
1320 }
1321 
1322 void play_dead_common(void)
1323 {
1324 	idle_task_exit();
1325 	reset_lazy_tlbstate();
1326 	irq_ctx_exit(raw_smp_processor_id());
1327 	c1e_remove_cpu(raw_smp_processor_id());
1328 
1329 	mb();
1330 	/* Ack it */
1331 	__get_cpu_var(cpu_state) = CPU_DEAD;
1332 
1333 	/*
1334 	 * With physical CPU hotplug, we should halt the cpu
1335 	 */
1336 	local_irq_disable();
1337 }
1338 
1339 void native_play_dead(void)
1340 {
1341 	play_dead_common();
1342 	tboot_shutdown(TB_SHUTDOWN_WFS);
1343 	wbinvd_halt();
1344 }
1345 
1346 #else /* ... !CONFIG_HOTPLUG_CPU */
1347 int native_cpu_disable(void)
1348 {
1349 	return -ENOSYS;
1350 }
1351 
1352 void native_cpu_die(unsigned int cpu)
1353 {
1354 	/* We said "no" in __cpu_disable */
1355 	BUG();
1356 }
1357 
1358 void native_play_dead(void)
1359 {
1360 	BUG();
1361 }
1362 
1363 #endif
1364