xref: /linux/arch/x86/kernel/smpboot.c (revision d39d0ed196aa1685bb24771e92f78633c66ac9cb)
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 #include <linux/stackprotector.h>
52 #include <linux/gfp.h>
53 
54 #include <asm/acpi.h>
55 #include <asm/desc.h>
56 #include <asm/nmi.h>
57 #include <asm/irq.h>
58 #include <asm/idle.h>
59 #include <asm/trampoline.h>
60 #include <asm/cpu.h>
61 #include <asm/numa.h>
62 #include <asm/pgtable.h>
63 #include <asm/tlbflush.h>
64 #include <asm/mtrr.h>
65 #include <asm/vmi.h>
66 #include <asm/apic.h>
67 #include <asm/setup.h>
68 #include <asm/uv/uv.h>
69 #include <linux/mc146818rtc.h>
70 
71 #include <asm/smpboot_hooks.h>
72 #include <asm/i8259.h>
73 
74 #ifdef CONFIG_X86_32
75 u8 apicid_2_node[MAX_APICID];
76 static int low_mappings;
77 #endif
78 
79 /* State of each CPU */
80 DEFINE_PER_CPU(int, cpu_state) = { 0 };
81 
82 /* Store all idle threads, this can be reused instead of creating
83 * a new thread. Also avoids complicated thread destroy functionality
84 * for idle threads.
85 */
86 #ifdef CONFIG_HOTPLUG_CPU
87 /*
88  * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
89  * removed after init for !CONFIG_HOTPLUG_CPU.
90  */
91 static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
92 #define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
93 #define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
94 #else
95 static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
96 #define get_idle_for_cpu(x)      (idle_thread_array[(x)])
97 #define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
98 #endif
99 
100 /* Number of siblings per CPU package */
101 int smp_num_siblings = 1;
102 EXPORT_SYMBOL(smp_num_siblings);
103 
104 /* Last level cache ID of each logical CPU */
105 DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID;
106 
107 /* representing HT siblings of each logical CPU */
108 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
109 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
110 
111 /* representing HT and core siblings of each logical CPU */
112 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
113 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
114 
115 /* Per CPU bogomips and other parameters */
116 DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
117 EXPORT_PER_CPU_SYMBOL(cpu_info);
118 
119 atomic_t init_deasserted;
120 
121 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_32)
122 /* which node each logical CPU is on */
123 int cpu_to_node_map[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 };
124 EXPORT_SYMBOL(cpu_to_node_map);
125 
126 /* set up a mapping between cpu and node. */
127 static void map_cpu_to_node(int cpu, int node)
128 {
129 	printk(KERN_INFO "Mapping cpu %d to node %d\n", cpu, node);
130 	cpumask_set_cpu(cpu, node_to_cpumask_map[node]);
131 	cpu_to_node_map[cpu] = node;
132 }
133 
134 /* undo a mapping between cpu and node. */
135 static void unmap_cpu_to_node(int cpu)
136 {
137 	int node;
138 
139 	printk(KERN_INFO "Unmapping cpu %d from all nodes\n", cpu);
140 	for (node = 0; node < MAX_NUMNODES; node++)
141 		cpumask_clear_cpu(cpu, node_to_cpumask_map[node]);
142 	cpu_to_node_map[cpu] = 0;
143 }
144 #else /* !(CONFIG_NUMA && CONFIG_X86_32) */
145 #define map_cpu_to_node(cpu, node)	({})
146 #define unmap_cpu_to_node(cpu)	({})
147 #endif
148 
149 #ifdef CONFIG_X86_32
150 static int boot_cpu_logical_apicid;
151 
152 u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly =
153 					{ [0 ... NR_CPUS-1] = BAD_APICID };
154 
155 static void map_cpu_to_logical_apicid(void)
156 {
157 	int cpu = smp_processor_id();
158 	int apicid = logical_smp_processor_id();
159 	int node = apic->apicid_to_node(apicid);
160 
161 	if (!node_online(node))
162 		node = first_online_node;
163 
164 	cpu_2_logical_apicid[cpu] = apicid;
165 	map_cpu_to_node(cpu, node);
166 }
167 
168 void numa_remove_cpu(int cpu)
169 {
170 	cpu_2_logical_apicid[cpu] = BAD_APICID;
171 	unmap_cpu_to_node(cpu);
172 }
173 #else
174 #define map_cpu_to_logical_apicid()  do {} while (0)
175 #endif
176 
177 /*
178  * Report back to the Boot Processor.
179  * Running on AP.
180  */
181 static void __cpuinit smp_callin(void)
182 {
183 	int cpuid, phys_id;
184 	unsigned long timeout;
185 
186 	/*
187 	 * If waken up by an INIT in an 82489DX configuration
188 	 * we may get here before an INIT-deassert IPI reaches
189 	 * our local APIC.  We have to wait for the IPI or we'll
190 	 * lock up on an APIC access.
191 	 */
192 	if (apic->wait_for_init_deassert)
193 		apic->wait_for_init_deassert(&init_deasserted);
194 
195 	/*
196 	 * (This works even if the APIC is not enabled.)
197 	 */
198 	phys_id = read_apic_id();
199 	cpuid = smp_processor_id();
200 	if (cpumask_test_cpu(cpuid, cpu_callin_mask)) {
201 		panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
202 					phys_id, cpuid);
203 	}
204 	pr_debug("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
205 
206 	/*
207 	 * STARTUP IPIs are fragile beasts as they might sometimes
208 	 * trigger some glue motherboard logic. Complete APIC bus
209 	 * silence for 1 second, this overestimates the time the
210 	 * boot CPU is spending to send the up to 2 STARTUP IPIs
211 	 * by a factor of two. This should be enough.
212 	 */
213 
214 	/*
215 	 * Waiting 2s total for startup (udelay is not yet working)
216 	 */
217 	timeout = jiffies + 2*HZ;
218 	while (time_before(jiffies, timeout)) {
219 		/*
220 		 * Has the boot CPU finished it's STARTUP sequence?
221 		 */
222 		if (cpumask_test_cpu(cpuid, cpu_callout_mask))
223 			break;
224 		cpu_relax();
225 	}
226 
227 	if (!time_before(jiffies, timeout)) {
228 		panic("%s: CPU%d started up but did not get a callout!\n",
229 		      __func__, cpuid);
230 	}
231 
232 	/*
233 	 * the boot CPU has finished the init stage and is spinning
234 	 * on callin_map until we finish. We are free to set up this
235 	 * CPU, first the APIC. (this is probably redundant on most
236 	 * boards)
237 	 */
238 
239 	pr_debug("CALLIN, before setup_local_APIC().\n");
240 	if (apic->smp_callin_clear_local_apic)
241 		apic->smp_callin_clear_local_apic();
242 	setup_local_APIC();
243 	end_local_APIC_setup();
244 	map_cpu_to_logical_apicid();
245 
246 	/*
247 	 * Need to setup vector mappings before we enable interrupts.
248 	 */
249 	setup_vector_irq(smp_processor_id());
250 	/*
251 	 * Get our bogomips.
252 	 *
253 	 * Need to enable IRQs because it can take longer and then
254 	 * the NMI watchdog might kill us.
255 	 */
256 	local_irq_enable();
257 	calibrate_delay();
258 	local_irq_disable();
259 	pr_debug("Stack at about %p\n", &cpuid);
260 
261 	/*
262 	 * Save our processor parameters
263 	 */
264 	smp_store_cpu_info(cpuid);
265 
266 	notify_cpu_starting(cpuid);
267 
268 	/*
269 	 * Allow the master to continue.
270 	 */
271 	cpumask_set_cpu(cpuid, cpu_callin_mask);
272 }
273 
274 /*
275  * Activate a secondary processor.
276  */
277 notrace static void __cpuinit start_secondary(void *unused)
278 {
279 	/*
280 	 * Don't put *anything* before cpu_init(), SMP booting is too
281 	 * fragile that we want to limit the things done here to the
282 	 * most necessary things.
283 	 */
284 	vmi_bringup();
285 	cpu_init();
286 	preempt_disable();
287 	smp_callin();
288 
289 	/* otherwise gcc will move up smp_processor_id before the cpu_init */
290 	barrier();
291 	/*
292 	 * Check TSC synchronization with the BP:
293 	 */
294 	check_tsc_sync_target();
295 
296 	if (nmi_watchdog == NMI_IO_APIC) {
297 		legacy_pic->chip->mask(0);
298 		enable_NMI_through_LVT0();
299 		legacy_pic->chip->unmask(0);
300 	}
301 
302 #ifdef CONFIG_X86_32
303 	while (low_mappings)
304 		cpu_relax();
305 	__flush_tlb_all();
306 #endif
307 
308 	/* This must be done before setting cpu_online_mask */
309 	set_cpu_sibling_map(raw_smp_processor_id());
310 	wmb();
311 
312 	/*
313 	 * We need to hold call_lock, so there is no inconsistency
314 	 * between the time smp_call_function() determines number of
315 	 * IPI recipients, and the time when the determination is made
316 	 * for which cpus receive the IPI. Holding this
317 	 * lock helps us to not include this cpu in a currently in progress
318 	 * smp_call_function().
319 	 *
320 	 * We need to hold vector_lock so there the set of online cpus
321 	 * does not change while we are assigning vectors to cpus.  Holding
322 	 * this lock ensures we don't half assign or remove an irq from a cpu.
323 	 */
324 	ipi_call_lock();
325 	lock_vector_lock();
326 	set_cpu_online(smp_processor_id(), true);
327 	unlock_vector_lock();
328 	ipi_call_unlock();
329 	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
330 	x86_platform.nmi_init();
331 
332 	/* enable local interrupts */
333 	local_irq_enable();
334 
335 	/* to prevent fake stack check failure in clock setup */
336 	boot_init_stack_canary();
337 
338 	x86_cpuinit.setup_percpu_clockev();
339 
340 	wmb();
341 	cpu_idle();
342 }
343 
344 #ifdef CONFIG_CPUMASK_OFFSTACK
345 /* In this case, llc_shared_map is a pointer to a cpumask. */
346 static inline void copy_cpuinfo_x86(struct cpuinfo_x86 *dst,
347 				    const struct cpuinfo_x86 *src)
348 {
349 	struct cpumask *llc = dst->llc_shared_map;
350 	*dst = *src;
351 	dst->llc_shared_map = llc;
352 }
353 #else
354 static inline void copy_cpuinfo_x86(struct cpuinfo_x86 *dst,
355 				    const struct cpuinfo_x86 *src)
356 {
357 	*dst = *src;
358 }
359 #endif /* CONFIG_CPUMASK_OFFSTACK */
360 
361 /*
362  * The bootstrap kernel entry code has set these up. Save them for
363  * a given CPU
364  */
365 
366 void __cpuinit smp_store_cpu_info(int id)
367 {
368 	struct cpuinfo_x86 *c = &cpu_data(id);
369 
370 	copy_cpuinfo_x86(c, &boot_cpu_data);
371 	c->cpu_index = id;
372 	if (id != 0)
373 		identify_secondary_cpu(c);
374 }
375 
376 
377 void __cpuinit set_cpu_sibling_map(int cpu)
378 {
379 	int i;
380 	struct cpuinfo_x86 *c = &cpu_data(cpu);
381 
382 	cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
383 
384 	if (smp_num_siblings > 1) {
385 		for_each_cpu(i, cpu_sibling_setup_mask) {
386 			struct cpuinfo_x86 *o = &cpu_data(i);
387 
388 			if (c->phys_proc_id == o->phys_proc_id &&
389 			    c->cpu_core_id == o->cpu_core_id) {
390 				cpumask_set_cpu(i, cpu_sibling_mask(cpu));
391 				cpumask_set_cpu(cpu, cpu_sibling_mask(i));
392 				cpumask_set_cpu(i, cpu_core_mask(cpu));
393 				cpumask_set_cpu(cpu, cpu_core_mask(i));
394 				cpumask_set_cpu(i, c->llc_shared_map);
395 				cpumask_set_cpu(cpu, o->llc_shared_map);
396 			}
397 		}
398 	} else {
399 		cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
400 	}
401 
402 	cpumask_set_cpu(cpu, c->llc_shared_map);
403 
404 	if (current_cpu_data.x86_max_cores == 1) {
405 		cpumask_copy(cpu_core_mask(cpu), cpu_sibling_mask(cpu));
406 		c->booted_cores = 1;
407 		return;
408 	}
409 
410 	for_each_cpu(i, cpu_sibling_setup_mask) {
411 		if (per_cpu(cpu_llc_id, cpu) != BAD_APICID &&
412 		    per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) {
413 			cpumask_set_cpu(i, c->llc_shared_map);
414 			cpumask_set_cpu(cpu, cpu_data(i).llc_shared_map);
415 		}
416 		if (c->phys_proc_id == cpu_data(i).phys_proc_id) {
417 			cpumask_set_cpu(i, cpu_core_mask(cpu));
418 			cpumask_set_cpu(cpu, cpu_core_mask(i));
419 			/*
420 			 *  Does this new cpu bringup a new core?
421 			 */
422 			if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) {
423 				/*
424 				 * for each core in package, increment
425 				 * the booted_cores for this new cpu
426 				 */
427 				if (cpumask_first(cpu_sibling_mask(i)) == i)
428 					c->booted_cores++;
429 				/*
430 				 * increment the core count for all
431 				 * the other cpus in this package
432 				 */
433 				if (i != cpu)
434 					cpu_data(i).booted_cores++;
435 			} else if (i != cpu && !c->booted_cores)
436 				c->booted_cores = cpu_data(i).booted_cores;
437 		}
438 	}
439 }
440 
441 /* maps the cpu to the sched domain representing multi-core */
442 const struct cpumask *cpu_coregroup_mask(int cpu)
443 {
444 	struct cpuinfo_x86 *c = &cpu_data(cpu);
445 	/*
446 	 * For perf, we return last level cache shared map.
447 	 * And for power savings, we return cpu_core_map
448 	 */
449 	if ((sched_mc_power_savings || sched_smt_power_savings) &&
450 	    !(cpu_has(c, X86_FEATURE_AMD_DCM)))
451 		return cpu_core_mask(cpu);
452 	else
453 		return c->llc_shared_map;
454 }
455 
456 static void impress_friends(void)
457 {
458 	int cpu;
459 	unsigned long bogosum = 0;
460 	/*
461 	 * Allow the user to impress friends.
462 	 */
463 	pr_debug("Before bogomips.\n");
464 	for_each_possible_cpu(cpu)
465 		if (cpumask_test_cpu(cpu, cpu_callout_mask))
466 			bogosum += cpu_data(cpu).loops_per_jiffy;
467 	printk(KERN_INFO
468 		"Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
469 		num_online_cpus(),
470 		bogosum/(500000/HZ),
471 		(bogosum/(5000/HZ))%100);
472 
473 	pr_debug("Before bogocount - setting activated=1.\n");
474 }
475 
476 void __inquire_remote_apic(int apicid)
477 {
478 	unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
479 	char *names[] = { "ID", "VERSION", "SPIV" };
480 	int timeout;
481 	u32 status;
482 
483 	printk(KERN_INFO "Inquiring remote APIC 0x%x...\n", apicid);
484 
485 	for (i = 0; i < ARRAY_SIZE(regs); i++) {
486 		printk(KERN_INFO "... APIC 0x%x %s: ", apicid, names[i]);
487 
488 		/*
489 		 * Wait for idle.
490 		 */
491 		status = safe_apic_wait_icr_idle();
492 		if (status)
493 			printk(KERN_CONT
494 			       "a previous APIC delivery may have failed\n");
495 
496 		apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
497 
498 		timeout = 0;
499 		do {
500 			udelay(100);
501 			status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
502 		} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
503 
504 		switch (status) {
505 		case APIC_ICR_RR_VALID:
506 			status = apic_read(APIC_RRR);
507 			printk(KERN_CONT "%08x\n", status);
508 			break;
509 		default:
510 			printk(KERN_CONT "failed\n");
511 		}
512 	}
513 }
514 
515 /*
516  * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
517  * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
518  * won't ... remember to clear down the APIC, etc later.
519  */
520 int __cpuinit
521 wakeup_secondary_cpu_via_nmi(int logical_apicid, unsigned long start_eip)
522 {
523 	unsigned long send_status, accept_status = 0;
524 	int maxlvt;
525 
526 	/* Target chip */
527 	/* Boot on the stack */
528 	/* Kick the second */
529 	apic_icr_write(APIC_DM_NMI | apic->dest_logical, logical_apicid);
530 
531 	pr_debug("Waiting for send to finish...\n");
532 	send_status = safe_apic_wait_icr_idle();
533 
534 	/*
535 	 * Give the other CPU some time to accept the IPI.
536 	 */
537 	udelay(200);
538 	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
539 		maxlvt = lapic_get_maxlvt();
540 		if (maxlvt > 3)			/* Due to the Pentium erratum 3AP.  */
541 			apic_write(APIC_ESR, 0);
542 		accept_status = (apic_read(APIC_ESR) & 0xEF);
543 	}
544 	pr_debug("NMI sent.\n");
545 
546 	if (send_status)
547 		printk(KERN_ERR "APIC never delivered???\n");
548 	if (accept_status)
549 		printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
550 
551 	return (send_status | accept_status);
552 }
553 
554 static int __cpuinit
555 wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
556 {
557 	unsigned long send_status, accept_status = 0;
558 	int maxlvt, num_starts, j;
559 
560 	maxlvt = lapic_get_maxlvt();
561 
562 	/*
563 	 * Be paranoid about clearing APIC errors.
564 	 */
565 	if (APIC_INTEGRATED(apic_version[phys_apicid])) {
566 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
567 			apic_write(APIC_ESR, 0);
568 		apic_read(APIC_ESR);
569 	}
570 
571 	pr_debug("Asserting INIT.\n");
572 
573 	/*
574 	 * Turn INIT on target chip
575 	 */
576 	/*
577 	 * Send IPI
578 	 */
579 	apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
580 		       phys_apicid);
581 
582 	pr_debug("Waiting for send to finish...\n");
583 	send_status = safe_apic_wait_icr_idle();
584 
585 	mdelay(10);
586 
587 	pr_debug("Deasserting INIT.\n");
588 
589 	/* Target chip */
590 	/* Send IPI */
591 	apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
592 
593 	pr_debug("Waiting for send to finish...\n");
594 	send_status = safe_apic_wait_icr_idle();
595 
596 	mb();
597 	atomic_set(&init_deasserted, 1);
598 
599 	/*
600 	 * Should we send STARTUP IPIs ?
601 	 *
602 	 * Determine this based on the APIC version.
603 	 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
604 	 */
605 	if (APIC_INTEGRATED(apic_version[phys_apicid]))
606 		num_starts = 2;
607 	else
608 		num_starts = 0;
609 
610 	/*
611 	 * Paravirt / VMI wants a startup IPI hook here to set up the
612 	 * target processor state.
613 	 */
614 	startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
615 			 (unsigned long)stack_start.sp);
616 
617 	/*
618 	 * Run STARTUP IPI loop.
619 	 */
620 	pr_debug("#startup loops: %d.\n", num_starts);
621 
622 	for (j = 1; j <= num_starts; j++) {
623 		pr_debug("Sending STARTUP #%d.\n", j);
624 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
625 			apic_write(APIC_ESR, 0);
626 		apic_read(APIC_ESR);
627 		pr_debug("After apic_write.\n");
628 
629 		/*
630 		 * STARTUP IPI
631 		 */
632 
633 		/* Target chip */
634 		/* Boot on the stack */
635 		/* Kick the second */
636 		apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
637 			       phys_apicid);
638 
639 		/*
640 		 * Give the other CPU some time to accept the IPI.
641 		 */
642 		udelay(300);
643 
644 		pr_debug("Startup point 1.\n");
645 
646 		pr_debug("Waiting for send to finish...\n");
647 		send_status = safe_apic_wait_icr_idle();
648 
649 		/*
650 		 * Give the other CPU some time to accept the IPI.
651 		 */
652 		udelay(200);
653 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
654 			apic_write(APIC_ESR, 0);
655 		accept_status = (apic_read(APIC_ESR) & 0xEF);
656 		if (send_status || accept_status)
657 			break;
658 	}
659 	pr_debug("After Startup.\n");
660 
661 	if (send_status)
662 		printk(KERN_ERR "APIC never delivered???\n");
663 	if (accept_status)
664 		printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
665 
666 	return (send_status | accept_status);
667 }
668 
669 struct create_idle {
670 	struct work_struct work;
671 	struct task_struct *idle;
672 	struct completion done;
673 	int cpu;
674 };
675 
676 static void __cpuinit do_fork_idle(struct work_struct *work)
677 {
678 	struct create_idle *c_idle =
679 		container_of(work, struct create_idle, work);
680 
681 	c_idle->idle = fork_idle(c_idle->cpu);
682 	complete(&c_idle->done);
683 }
684 
685 /* reduce the number of lines printed when booting a large cpu count system */
686 static void __cpuinit announce_cpu(int cpu, int apicid)
687 {
688 	static int current_node = -1;
689 	int node = early_cpu_to_node(cpu);
690 
691 	if (system_state == SYSTEM_BOOTING) {
692 		if (node != current_node) {
693 			if (current_node > (-1))
694 				pr_cont(" Ok.\n");
695 			current_node = node;
696 			pr_info("Booting Node %3d, Processors ", node);
697 		}
698 		pr_cont(" #%d%s", cpu, cpu == (nr_cpu_ids - 1) ? " Ok.\n" : "");
699 		return;
700 	} else
701 		pr_info("Booting Node %d Processor %d APIC 0x%x\n",
702 			node, cpu, apicid);
703 }
704 
705 /*
706  * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
707  * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
708  * Returns zero if CPU booted OK, else error code from
709  * ->wakeup_secondary_cpu.
710  */
711 static int __cpuinit do_boot_cpu(int apicid, int cpu)
712 {
713 	unsigned long boot_error = 0;
714 	unsigned long start_ip;
715 	int timeout;
716 	struct create_idle c_idle = {
717 		.cpu	= cpu,
718 		.done	= COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
719 	};
720 
721 	INIT_WORK_ON_STACK(&c_idle.work, do_fork_idle);
722 
723 	alternatives_smp_switch(1);
724 
725 	c_idle.idle = get_idle_for_cpu(cpu);
726 
727 	/*
728 	 * We can't use kernel_thread since we must avoid to
729 	 * reschedule the child.
730 	 */
731 	if (c_idle.idle) {
732 		c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
733 			(THREAD_SIZE +  task_stack_page(c_idle.idle))) - 1);
734 		init_idle(c_idle.idle, cpu);
735 		goto do_rest;
736 	}
737 
738 	schedule_work(&c_idle.work);
739 	wait_for_completion(&c_idle.done);
740 
741 	if (IS_ERR(c_idle.idle)) {
742 		printk("failed fork for CPU %d\n", cpu);
743 		destroy_work_on_stack(&c_idle.work);
744 		return PTR_ERR(c_idle.idle);
745 	}
746 
747 	set_idle_for_cpu(cpu, c_idle.idle);
748 do_rest:
749 	per_cpu(current_task, cpu) = c_idle.idle;
750 #ifdef CONFIG_X86_32
751 	/* Stack for startup_32 can be just as for start_secondary onwards */
752 	irq_ctx_init(cpu);
753 #else
754 	clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
755 	initial_gs = per_cpu_offset(cpu);
756 	per_cpu(kernel_stack, cpu) =
757 		(unsigned long)task_stack_page(c_idle.idle) -
758 		KERNEL_STACK_OFFSET + THREAD_SIZE;
759 #endif
760 	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
761 	initial_code = (unsigned long)start_secondary;
762 	stack_start.sp = (void *) c_idle.idle->thread.sp;
763 
764 	/* start_ip had better be page-aligned! */
765 	start_ip = setup_trampoline();
766 
767 	/* So we see what's up */
768 	announce_cpu(cpu, apicid);
769 
770 	/*
771 	 * This grunge runs the startup process for
772 	 * the targeted processor.
773 	 */
774 
775 	atomic_set(&init_deasserted, 0);
776 
777 	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
778 
779 		pr_debug("Setting warm reset code and vector.\n");
780 
781 		smpboot_setup_warm_reset_vector(start_ip);
782 		/*
783 		 * Be paranoid about clearing APIC errors.
784 		*/
785 		if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
786 			apic_write(APIC_ESR, 0);
787 			apic_read(APIC_ESR);
788 		}
789 	}
790 
791 	/*
792 	 * Kick the secondary CPU. Use the method in the APIC driver
793 	 * if it's defined - or use an INIT boot APIC message otherwise:
794 	 */
795 	if (apic->wakeup_secondary_cpu)
796 		boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
797 	else
798 		boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
799 
800 	if (!boot_error) {
801 		/*
802 		 * allow APs to start initializing.
803 		 */
804 		pr_debug("Before Callout %d.\n", cpu);
805 		cpumask_set_cpu(cpu, cpu_callout_mask);
806 		pr_debug("After Callout %d.\n", cpu);
807 
808 		/*
809 		 * Wait 5s total for a response
810 		 */
811 		for (timeout = 0; timeout < 50000; timeout++) {
812 			if (cpumask_test_cpu(cpu, cpu_callin_mask))
813 				break;	/* It has booted */
814 			udelay(100);
815 			/*
816 			 * Allow other tasks to run while we wait for the
817 			 * AP to come online. This also gives a chance
818 			 * for the MTRR work(triggered by the AP coming online)
819 			 * to be completed in the stop machine context.
820 			 */
821 			schedule();
822 		}
823 
824 		if (cpumask_test_cpu(cpu, cpu_callin_mask))
825 			pr_debug("CPU%d: has booted.\n", cpu);
826 		else {
827 			boot_error = 1;
828 			if (*((volatile unsigned char *)trampoline_base)
829 					== 0xA5)
830 				/* trampoline started but...? */
831 				pr_err("CPU%d: Stuck ??\n", cpu);
832 			else
833 				/* trampoline code not run */
834 				pr_err("CPU%d: Not responding.\n", cpu);
835 			if (apic->inquire_remote_apic)
836 				apic->inquire_remote_apic(apicid);
837 		}
838 	}
839 
840 	if (boot_error) {
841 		/* Try to put things back the way they were before ... */
842 		numa_remove_cpu(cpu); /* was set by numa_add_cpu */
843 
844 		/* was set by do_boot_cpu() */
845 		cpumask_clear_cpu(cpu, cpu_callout_mask);
846 
847 		/* was set by cpu_init() */
848 		cpumask_clear_cpu(cpu, cpu_initialized_mask);
849 
850 		set_cpu_present(cpu, false);
851 		per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
852 	}
853 
854 	/* mark "stuck" area as not stuck */
855 	*((volatile unsigned long *)trampoline_base) = 0;
856 
857 	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
858 		/*
859 		 * Cleanup possible dangling ends...
860 		 */
861 		smpboot_restore_warm_reset_vector();
862 	}
863 
864 	destroy_work_on_stack(&c_idle.work);
865 	return boot_error;
866 }
867 
868 int __cpuinit native_cpu_up(unsigned int cpu)
869 {
870 	int apicid = apic->cpu_present_to_apicid(cpu);
871 	unsigned long flags;
872 	int err;
873 
874 	WARN_ON(irqs_disabled());
875 
876 	pr_debug("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
877 
878 	if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid ||
879 	    !physid_isset(apicid, phys_cpu_present_map)) {
880 		printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu);
881 		return -EINVAL;
882 	}
883 
884 	/*
885 	 * Already booted CPU?
886 	 */
887 	if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
888 		pr_debug("do_boot_cpu %d Already started\n", cpu);
889 		return -ENOSYS;
890 	}
891 
892 	/*
893 	 * Save current MTRR state in case it was changed since early boot
894 	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
895 	 */
896 	mtrr_save_state();
897 
898 	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
899 
900 #ifdef CONFIG_X86_32
901 	/* init low mem mapping */
902 	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
903 		min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
904 	flush_tlb_all();
905 	low_mappings = 1;
906 
907 	err = do_boot_cpu(apicid, cpu);
908 
909 	zap_low_mappings(false);
910 	low_mappings = 0;
911 #else
912 	err = do_boot_cpu(apicid, cpu);
913 #endif
914 	if (err) {
915 		pr_debug("do_boot_cpu failed %d\n", err);
916 		return -EIO;
917 	}
918 
919 	/*
920 	 * Check TSC synchronization with the AP (keep irqs disabled
921 	 * while doing so):
922 	 */
923 	local_irq_save(flags);
924 	check_tsc_sync_source(cpu);
925 	local_irq_restore(flags);
926 
927 	while (!cpu_online(cpu)) {
928 		cpu_relax();
929 		touch_nmi_watchdog();
930 	}
931 
932 	return 0;
933 }
934 
935 /*
936  * Fall back to non SMP mode after errors.
937  *
938  * RED-PEN audit/test this more. I bet there is more state messed up here.
939  */
940 static __init void disable_smp(void)
941 {
942 	init_cpu_present(cpumask_of(0));
943 	init_cpu_possible(cpumask_of(0));
944 	smpboot_clear_io_apic_irqs();
945 
946 	if (smp_found_config)
947 		physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
948 	else
949 		physid_set_mask_of_physid(0, &phys_cpu_present_map);
950 	map_cpu_to_logical_apicid();
951 	cpumask_set_cpu(0, cpu_sibling_mask(0));
952 	cpumask_set_cpu(0, cpu_core_mask(0));
953 }
954 
955 /*
956  * Various sanity checks.
957  */
958 static int __init smp_sanity_check(unsigned max_cpus)
959 {
960 	preempt_disable();
961 
962 #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
963 	if (def_to_bigsmp && nr_cpu_ids > 8) {
964 		unsigned int cpu;
965 		unsigned nr;
966 
967 		printk(KERN_WARNING
968 		       "More than 8 CPUs detected - skipping them.\n"
969 		       "Use CONFIG_X86_BIGSMP.\n");
970 
971 		nr = 0;
972 		for_each_present_cpu(cpu) {
973 			if (nr >= 8)
974 				set_cpu_present(cpu, false);
975 			nr++;
976 		}
977 
978 		nr = 0;
979 		for_each_possible_cpu(cpu) {
980 			if (nr >= 8)
981 				set_cpu_possible(cpu, false);
982 			nr++;
983 		}
984 
985 		nr_cpu_ids = 8;
986 	}
987 #endif
988 
989 	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
990 		printk(KERN_WARNING
991 			"weird, boot CPU (#%d) not listed by the BIOS.\n",
992 			hard_smp_processor_id());
993 
994 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
995 	}
996 
997 	/*
998 	 * If we couldn't find an SMP configuration at boot time,
999 	 * get out of here now!
1000 	 */
1001 	if (!smp_found_config && !acpi_lapic) {
1002 		preempt_enable();
1003 		printk(KERN_NOTICE "SMP motherboard not detected.\n");
1004 		disable_smp();
1005 		if (APIC_init_uniprocessor())
1006 			printk(KERN_NOTICE "Local APIC not detected."
1007 					   " Using dummy APIC emulation.\n");
1008 		return -1;
1009 	}
1010 
1011 	/*
1012 	 * Should not be necessary because the MP table should list the boot
1013 	 * CPU too, but we do it for the sake of robustness anyway.
1014 	 */
1015 	if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
1016 		printk(KERN_NOTICE
1017 			"weird, boot CPU (#%d) not listed by the BIOS.\n",
1018 			boot_cpu_physical_apicid);
1019 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
1020 	}
1021 	preempt_enable();
1022 
1023 	/*
1024 	 * If we couldn't find a local APIC, then get out of here now!
1025 	 */
1026 	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
1027 	    !cpu_has_apic) {
1028 		if (!disable_apic) {
1029 			pr_err("BIOS bug, local APIC #%d not detected!...\n",
1030 				boot_cpu_physical_apicid);
1031 			pr_err("... forcing use of dummy APIC emulation."
1032 				"(tell your hw vendor)\n");
1033 		}
1034 		smpboot_clear_io_apic();
1035 		arch_disable_smp_support();
1036 		return -1;
1037 	}
1038 
1039 	verify_local_APIC();
1040 
1041 	/*
1042 	 * If SMP should be disabled, then really disable it!
1043 	 */
1044 	if (!max_cpus) {
1045 		printk(KERN_INFO "SMP mode deactivated.\n");
1046 		smpboot_clear_io_apic();
1047 
1048 		localise_nmi_watchdog();
1049 
1050 		connect_bsp_APIC();
1051 		setup_local_APIC();
1052 		end_local_APIC_setup();
1053 		return -1;
1054 	}
1055 
1056 	return 0;
1057 }
1058 
1059 static void __init smp_cpu_index_default(void)
1060 {
1061 	int i;
1062 	struct cpuinfo_x86 *c;
1063 
1064 	for_each_possible_cpu(i) {
1065 		c = &cpu_data(i);
1066 		/* mark all to hotplug */
1067 		c->cpu_index = nr_cpu_ids;
1068 	}
1069 }
1070 
1071 /*
1072  * Prepare for SMP bootup.  The MP table or ACPI has been read
1073  * earlier.  Just do some sanity checking here and enable APIC mode.
1074  */
1075 void __init native_smp_prepare_cpus(unsigned int max_cpus)
1076 {
1077 	unsigned int i;
1078 
1079 	preempt_disable();
1080 	smp_cpu_index_default();
1081 	current_cpu_data = boot_cpu_data;
1082 	cpumask_copy(cpu_callin_mask, cpumask_of(0));
1083 	mb();
1084 	/*
1085 	 * Setup boot CPU information
1086 	 */
1087 	smp_store_cpu_info(0); /* Final full version of the data */
1088 #ifdef CONFIG_X86_32
1089 	boot_cpu_logical_apicid = logical_smp_processor_id();
1090 #endif
1091 	current_thread_info()->cpu = 0;  /* needed? */
1092 	for_each_possible_cpu(i) {
1093 		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
1094 		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
1095 		zalloc_cpumask_var(&cpu_data(i).llc_shared_map, GFP_KERNEL);
1096 	}
1097 	set_cpu_sibling_map(0);
1098 
1099 	enable_IR_x2apic();
1100 	default_setup_apic_routing();
1101 
1102 	if (smp_sanity_check(max_cpus) < 0) {
1103 		printk(KERN_INFO "SMP disabled\n");
1104 		disable_smp();
1105 		goto out;
1106 	}
1107 
1108 	preempt_disable();
1109 	if (read_apic_id() != boot_cpu_physical_apicid) {
1110 		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
1111 		     read_apic_id(), boot_cpu_physical_apicid);
1112 		/* Or can we switch back to PIC here? */
1113 	}
1114 	preempt_enable();
1115 
1116 	connect_bsp_APIC();
1117 
1118 	/*
1119 	 * Switch from PIC to APIC mode.
1120 	 */
1121 	setup_local_APIC();
1122 
1123 	/*
1124 	 * Enable IO APIC before setting up error vector
1125 	 */
1126 	if (!skip_ioapic_setup && nr_ioapics)
1127 		enable_IO_APIC();
1128 
1129 	end_local_APIC_setup();
1130 
1131 	map_cpu_to_logical_apicid();
1132 
1133 	if (apic->setup_portio_remap)
1134 		apic->setup_portio_remap();
1135 
1136 	smpboot_setup_io_apic();
1137 	/*
1138 	 * Set up local APIC timer on boot CPU.
1139 	 */
1140 
1141 	printk(KERN_INFO "CPU%d: ", 0);
1142 	print_cpu_info(&cpu_data(0));
1143 	x86_init.timers.setup_percpu_clockev();
1144 
1145 	if (is_uv_system())
1146 		uv_system_init();
1147 
1148 	set_mtrr_aps_delayed_init();
1149 out:
1150 	preempt_enable();
1151 }
1152 
1153 void arch_enable_nonboot_cpus_begin(void)
1154 {
1155 	set_mtrr_aps_delayed_init();
1156 }
1157 
1158 void arch_enable_nonboot_cpus_end(void)
1159 {
1160 	mtrr_aps_init();
1161 }
1162 
1163 /*
1164  * Early setup to make printk work.
1165  */
1166 void __init native_smp_prepare_boot_cpu(void)
1167 {
1168 	int me = smp_processor_id();
1169 	switch_to_new_gdt(me);
1170 	/* already set me in cpu_online_mask in boot_cpu_init() */
1171 	cpumask_set_cpu(me, cpu_callout_mask);
1172 	per_cpu(cpu_state, me) = CPU_ONLINE;
1173 }
1174 
1175 void __init native_smp_cpus_done(unsigned int max_cpus)
1176 {
1177 	pr_debug("Boot done.\n");
1178 
1179 	impress_friends();
1180 #ifdef CONFIG_X86_IO_APIC
1181 	setup_ioapic_dest();
1182 #endif
1183 	check_nmi_watchdog();
1184 	mtrr_aps_init();
1185 }
1186 
1187 static int __initdata setup_possible_cpus = -1;
1188 static int __init _setup_possible_cpus(char *str)
1189 {
1190 	get_option(&str, &setup_possible_cpus);
1191 	return 0;
1192 }
1193 early_param("possible_cpus", _setup_possible_cpus);
1194 
1195 
1196 /*
1197  * cpu_possible_mask should be static, it cannot change as cpu's
1198  * are onlined, or offlined. The reason is per-cpu data-structures
1199  * are allocated by some modules at init time, and dont expect to
1200  * do this dynamically on cpu arrival/departure.
1201  * cpu_present_mask on the other hand can change dynamically.
1202  * In case when cpu_hotplug is not compiled, then we resort to current
1203  * behaviour, which is cpu_possible == cpu_present.
1204  * - Ashok Raj
1205  *
1206  * Three ways to find out the number of additional hotplug CPUs:
1207  * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
1208  * - The user can overwrite it with possible_cpus=NUM
1209  * - Otherwise don't reserve additional CPUs.
1210  * We do this because additional CPUs waste a lot of memory.
1211  * -AK
1212  */
1213 __init void prefill_possible_map(void)
1214 {
1215 	int i, possible;
1216 
1217 	/* no processor from mptable or madt */
1218 	if (!num_processors)
1219 		num_processors = 1;
1220 
1221 	i = setup_max_cpus ?: 1;
1222 	if (setup_possible_cpus == -1) {
1223 		possible = num_processors;
1224 #ifdef CONFIG_HOTPLUG_CPU
1225 		if (setup_max_cpus)
1226 			possible += disabled_cpus;
1227 #else
1228 		if (possible > i)
1229 			possible = i;
1230 #endif
1231 	} else
1232 		possible = setup_possible_cpus;
1233 
1234 	total_cpus = max_t(int, possible, num_processors + disabled_cpus);
1235 
1236 	/* nr_cpu_ids could be reduced via nr_cpus= */
1237 	if (possible > nr_cpu_ids) {
1238 		printk(KERN_WARNING
1239 			"%d Processors exceeds NR_CPUS limit of %d\n",
1240 			possible, nr_cpu_ids);
1241 		possible = nr_cpu_ids;
1242 	}
1243 
1244 #ifdef CONFIG_HOTPLUG_CPU
1245 	if (!setup_max_cpus)
1246 #endif
1247 	if (possible > i) {
1248 		printk(KERN_WARNING
1249 			"%d Processors exceeds max_cpus limit of %u\n",
1250 			possible, setup_max_cpus);
1251 		possible = i;
1252 	}
1253 
1254 	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
1255 		possible, max_t(int, possible - num_processors, 0));
1256 
1257 	for (i = 0; i < possible; i++)
1258 		set_cpu_possible(i, true);
1259 	for (; i < NR_CPUS; i++)
1260 		set_cpu_possible(i, false);
1261 
1262 	nr_cpu_ids = possible;
1263 }
1264 
1265 #ifdef CONFIG_HOTPLUG_CPU
1266 
1267 static void remove_siblinginfo(int cpu)
1268 {
1269 	int sibling;
1270 	struct cpuinfo_x86 *c = &cpu_data(cpu);
1271 
1272 	for_each_cpu(sibling, cpu_core_mask(cpu)) {
1273 		cpumask_clear_cpu(cpu, cpu_core_mask(sibling));
1274 		/*/
1275 		 * last thread sibling in this cpu core going down
1276 		 */
1277 		if (cpumask_weight(cpu_sibling_mask(cpu)) == 1)
1278 			cpu_data(sibling).booted_cores--;
1279 	}
1280 
1281 	for_each_cpu(sibling, cpu_sibling_mask(cpu))
1282 		cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
1283 	cpumask_clear(cpu_sibling_mask(cpu));
1284 	cpumask_clear(cpu_core_mask(cpu));
1285 	c->phys_proc_id = 0;
1286 	c->cpu_core_id = 0;
1287 	cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
1288 }
1289 
1290 static void __ref remove_cpu_from_maps(int cpu)
1291 {
1292 	set_cpu_online(cpu, false);
1293 	cpumask_clear_cpu(cpu, cpu_callout_mask);
1294 	cpumask_clear_cpu(cpu, cpu_callin_mask);
1295 	/* was set by cpu_init() */
1296 	cpumask_clear_cpu(cpu, cpu_initialized_mask);
1297 	numa_remove_cpu(cpu);
1298 }
1299 
1300 void cpu_disable_common(void)
1301 {
1302 	int cpu = smp_processor_id();
1303 
1304 	remove_siblinginfo(cpu);
1305 
1306 	/* It's now safe to remove this processor from the online map */
1307 	lock_vector_lock();
1308 	remove_cpu_from_maps(cpu);
1309 	unlock_vector_lock();
1310 	fixup_irqs();
1311 }
1312 
1313 int native_cpu_disable(void)
1314 {
1315 	int cpu = smp_processor_id();
1316 
1317 	/*
1318 	 * Perhaps use cpufreq to drop frequency, but that could go
1319 	 * into generic code.
1320 	 *
1321 	 * We won't take down the boot processor on i386 due to some
1322 	 * interrupts only being able to be serviced by the BSP.
1323 	 * Especially so if we're not using an IOAPIC	-zwane
1324 	 */
1325 	if (cpu == 0)
1326 		return -EBUSY;
1327 
1328 	if (nmi_watchdog == NMI_LOCAL_APIC)
1329 		stop_apic_nmi_watchdog(NULL);
1330 	clear_local_APIC();
1331 
1332 	cpu_disable_common();
1333 	return 0;
1334 }
1335 
1336 void native_cpu_die(unsigned int cpu)
1337 {
1338 	/* We don't do anything here: idle task is faking death itself. */
1339 	unsigned int i;
1340 
1341 	for (i = 0; i < 10; i++) {
1342 		/* They ack this in play_dead by setting CPU_DEAD */
1343 		if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
1344 			if (system_state == SYSTEM_RUNNING)
1345 				pr_info("CPU %u is now offline\n", cpu);
1346 
1347 			if (1 == num_online_cpus())
1348 				alternatives_smp_switch(0);
1349 			return;
1350 		}
1351 		msleep(100);
1352 	}
1353 	pr_err("CPU %u didn't die...\n", cpu);
1354 }
1355 
1356 void play_dead_common(void)
1357 {
1358 	idle_task_exit();
1359 	reset_lazy_tlbstate();
1360 	irq_ctx_exit(raw_smp_processor_id());
1361 	c1e_remove_cpu(raw_smp_processor_id());
1362 
1363 	mb();
1364 	/* Ack it */
1365 	__get_cpu_var(cpu_state) = CPU_DEAD;
1366 
1367 	/*
1368 	 * With physical CPU hotplug, we should halt the cpu
1369 	 */
1370 	local_irq_disable();
1371 }
1372 
1373 void native_play_dead(void)
1374 {
1375 	play_dead_common();
1376 	tboot_shutdown(TB_SHUTDOWN_WFS);
1377 	wbinvd_halt();
1378 }
1379 
1380 #else /* ... !CONFIG_HOTPLUG_CPU */
1381 int native_cpu_disable(void)
1382 {
1383 	return -ENOSYS;
1384 }
1385 
1386 void native_cpu_die(unsigned int cpu)
1387 {
1388 	/* We said "no" in __cpu_disable */
1389 	BUG();
1390 }
1391 
1392 void native_play_dead(void)
1393 {
1394 	BUG();
1395 }
1396 
1397 #endif
1398