xref: /linux/arch/x86/kernel/smpboot.c (revision 722ecdbce68a87de2d9296f91308f44ea900a039)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2  /*
3  *	x86 SMP booting functions
4  *
5  *	(c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
6  *	(c) 1998, 1999, 2000, 2009 Ingo Molnar <mingo@redhat.com>
7  *	Copyright 2001 Andi Kleen, SuSE Labs.
8  *
9  *	Much of the core SMP work is based on previous work by Thomas Radke, to
10  *	whom a great many thanks are extended.
11  *
12  *	Thanks to Intel for making available several different Pentium,
13  *	Pentium Pro and Pentium-II/Xeon MP machines.
14  *	Original development of Linux SMP code supported by Caldera.
15  *
16  *	Fixes
17  *		Felix Koop	:	NR_CPUS used properly
18  *		Jose Renau	:	Handle single CPU case.
19  *		Alan Cox	:	By repeated request 8) - Total BogoMIPS report.
20  *		Greg Wright	:	Fix for kernel stacks panic.
21  *		Erich Boleyn	:	MP v1.4 and additional changes.
22  *	Matthias Sattler	:	Changes for 2.1 kernel map.
23  *	Michel Lespinasse	:	Changes for 2.1 kernel map.
24  *	Michael Chastain	:	Change trampoline.S to gnu as.
25  *		Alan Cox	:	Dumb bug: 'B' step PPro's are fine
26  *		Ingo Molnar	:	Added APIC timers, based on code
27  *					from Jose Renau
28  *		Ingo Molnar	:	various cleanups and rewrites
29  *		Tigran Aivazian	:	fixed "0.00 in /proc/uptime on SMP" bug.
30  *	Maciej W. Rozycki	:	Bits for genuine 82489DX APICs
31  *	Andi Kleen		:	Changed for SMP boot into long mode.
32  *		Martin J. Bligh	: 	Added support for multi-quad systems
33  *		Dave Jones	:	Report invalid combinations of Athlon CPUs.
34  *		Rusty Russell	:	Hacked into shape for new "hotplug" boot process.
35  *      Andi Kleen              :       Converted to new state machine.
36  *	Ashok Raj		: 	CPU hotplug support
37  *	Glauber Costa		:	i386 and x86_64 integration
38  */
39 
40 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
41 
42 #include <linux/init.h>
43 #include <linux/smp.h>
44 #include <linux/export.h>
45 #include <linux/sched.h>
46 #include <linux/sched/topology.h>
47 #include <linux/sched/hotplug.h>
48 #include <linux/sched/task_stack.h>
49 #include <linux/percpu.h>
50 #include <linux/memblock.h>
51 #include <linux/err.h>
52 #include <linux/nmi.h>
53 #include <linux/tboot.h>
54 #include <linux/gfp.h>
55 #include <linux/cpuidle.h>
56 #include <linux/numa.h>
57 #include <linux/pgtable.h>
58 #include <linux/overflow.h>
59 
60 #include <asm/acpi.h>
61 #include <asm/desc.h>
62 #include <asm/nmi.h>
63 #include <asm/irq.h>
64 #include <asm/realmode.h>
65 #include <asm/cpu.h>
66 #include <asm/numa.h>
67 #include <asm/tlbflush.h>
68 #include <asm/mtrr.h>
69 #include <asm/mwait.h>
70 #include <asm/apic.h>
71 #include <asm/io_apic.h>
72 #include <asm/fpu/api.h>
73 #include <asm/setup.h>
74 #include <asm/uv/uv.h>
75 #include <linux/mc146818rtc.h>
76 #include <asm/i8259.h>
77 #include <asm/misc.h>
78 #include <asm/qspinlock.h>
79 #include <asm/intel-family.h>
80 #include <asm/cpu_device_id.h>
81 #include <asm/spec-ctrl.h>
82 #include <asm/hw_irq.h>
83 #include <asm/stackprotector.h>
84 #include <asm/sev.h>
85 
86 /* representing HT siblings of each logical CPU */
87 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
88 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
89 
90 /* representing HT and core siblings of each logical CPU */
91 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
92 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
93 
94 /* representing HT, core, and die siblings of each logical CPU */
95 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_die_map);
96 EXPORT_PER_CPU_SYMBOL(cpu_die_map);
97 
98 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
99 
100 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map);
101 
102 /* Per CPU bogomips and other parameters */
103 DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
104 EXPORT_PER_CPU_SYMBOL(cpu_info);
105 
106 /* Logical package management. We might want to allocate that dynamically */
107 unsigned int __max_logical_packages __read_mostly;
108 EXPORT_SYMBOL(__max_logical_packages);
109 static unsigned int logical_packages __read_mostly;
110 static unsigned int logical_die __read_mostly;
111 
112 /* Maximum number of SMT threads on any online core */
113 int __read_mostly __max_smt_threads = 1;
114 
115 /* Flag to indicate if a complete sched domain rebuild is required */
116 bool x86_topology_update;
117 
118 int arch_update_cpu_topology(void)
119 {
120 	int retval = x86_topology_update;
121 
122 	x86_topology_update = false;
123 	return retval;
124 }
125 
126 static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
127 {
128 	unsigned long flags;
129 
130 	spin_lock_irqsave(&rtc_lock, flags);
131 	CMOS_WRITE(0xa, 0xf);
132 	spin_unlock_irqrestore(&rtc_lock, flags);
133 	*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) =
134 							start_eip >> 4;
135 	*((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) =
136 							start_eip & 0xf;
137 }
138 
139 static inline void smpboot_restore_warm_reset_vector(void)
140 {
141 	unsigned long flags;
142 
143 	/*
144 	 * Paranoid:  Set warm reset code and vector here back
145 	 * to default values.
146 	 */
147 	spin_lock_irqsave(&rtc_lock, flags);
148 	CMOS_WRITE(0, 0xf);
149 	spin_unlock_irqrestore(&rtc_lock, flags);
150 
151 	*((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0;
152 }
153 
154 /*
155  * Report back to the Boot Processor during boot time or to the caller processor
156  * during CPU online.
157  */
158 static void smp_callin(void)
159 {
160 	int cpuid;
161 
162 	/*
163 	 * If waken up by an INIT in an 82489DX configuration
164 	 * cpu_callout_mask guarantees we don't get here before
165 	 * an INIT_deassert IPI reaches our local APIC, so it is
166 	 * now safe to touch our local APIC.
167 	 */
168 	cpuid = smp_processor_id();
169 
170 	/*
171 	 * the boot CPU has finished the init stage and is spinning
172 	 * on callin_map until we finish. We are free to set up this
173 	 * CPU, first the APIC. (this is probably redundant on most
174 	 * boards)
175 	 */
176 	apic_ap_setup();
177 
178 	/*
179 	 * Save our processor parameters. Note: this information
180 	 * is needed for clock calibration.
181 	 */
182 	smp_store_cpu_info(cpuid);
183 
184 	/*
185 	 * The topology information must be up to date before
186 	 * calibrate_delay() and notify_cpu_starting().
187 	 */
188 	set_cpu_sibling_map(raw_smp_processor_id());
189 
190 	ap_init_aperfmperf();
191 
192 	/*
193 	 * Get our bogomips.
194 	 * Update loops_per_jiffy in cpu_data. Previous call to
195 	 * smp_store_cpu_info() stored a value that is close but not as
196 	 * accurate as the value just calculated.
197 	 */
198 	calibrate_delay();
199 	cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
200 	pr_debug("Stack at about %p\n", &cpuid);
201 
202 	wmb();
203 
204 	notify_cpu_starting(cpuid);
205 
206 	/*
207 	 * Allow the master to continue.
208 	 */
209 	cpumask_set_cpu(cpuid, cpu_callin_mask);
210 }
211 
212 static int cpu0_logical_apicid;
213 static int enable_start_cpu0;
214 /*
215  * Activate a secondary processor.
216  */
217 static void notrace start_secondary(void *unused)
218 {
219 	/*
220 	 * Don't put *anything* except direct CPU state initialization
221 	 * before cpu_init(), SMP booting is too fragile that we want to
222 	 * limit the things done here to the most necessary things.
223 	 */
224 	cr4_init();
225 
226 #ifdef CONFIG_X86_32
227 	/* switch away from the initial page table */
228 	load_cr3(swapper_pg_dir);
229 	__flush_tlb_all();
230 #endif
231 	cpu_init_secondary();
232 	rcu_cpu_starting(raw_smp_processor_id());
233 	x86_cpuinit.early_percpu_clock_init();
234 	smp_callin();
235 
236 	enable_start_cpu0 = 0;
237 
238 	/* otherwise gcc will move up smp_processor_id before the cpu_init */
239 	barrier();
240 	/*
241 	 * Check TSC synchronization with the boot CPU:
242 	 */
243 	check_tsc_sync_target();
244 
245 	speculative_store_bypass_ht_init();
246 
247 	/*
248 	 * Lock vector_lock, set CPU online and bring the vector
249 	 * allocator online. Online must be set with vector_lock held
250 	 * to prevent a concurrent irq setup/teardown from seeing a
251 	 * half valid vector space.
252 	 */
253 	lock_vector_lock();
254 	set_cpu_online(smp_processor_id(), true);
255 	lapic_online();
256 	unlock_vector_lock();
257 	cpu_set_state_online(smp_processor_id());
258 	x86_platform.nmi_init();
259 
260 	/* enable local interrupts */
261 	local_irq_enable();
262 
263 	x86_cpuinit.setup_percpu_clockev();
264 
265 	wmb();
266 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
267 }
268 
269 /**
270  * topology_is_primary_thread - Check whether CPU is the primary SMT thread
271  * @cpu:	CPU to check
272  */
273 bool topology_is_primary_thread(unsigned int cpu)
274 {
275 	return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu));
276 }
277 
278 /**
279  * topology_smt_supported - Check whether SMT is supported by the CPUs
280  */
281 bool topology_smt_supported(void)
282 {
283 	return smp_num_siblings > 1;
284 }
285 
286 /**
287  * topology_phys_to_logical_pkg - Map a physical package id to a logical
288  *
289  * Returns logical package id or -1 if not found
290  */
291 int topology_phys_to_logical_pkg(unsigned int phys_pkg)
292 {
293 	int cpu;
294 
295 	for_each_possible_cpu(cpu) {
296 		struct cpuinfo_x86 *c = &cpu_data(cpu);
297 
298 		if (c->initialized && c->phys_proc_id == phys_pkg)
299 			return c->logical_proc_id;
300 	}
301 	return -1;
302 }
303 EXPORT_SYMBOL(topology_phys_to_logical_pkg);
304 /**
305  * topology_phys_to_logical_die - Map a physical die id to logical
306  *
307  * Returns logical die id or -1 if not found
308  */
309 int topology_phys_to_logical_die(unsigned int die_id, unsigned int cur_cpu)
310 {
311 	int cpu;
312 	int proc_id = cpu_data(cur_cpu).phys_proc_id;
313 
314 	for_each_possible_cpu(cpu) {
315 		struct cpuinfo_x86 *c = &cpu_data(cpu);
316 
317 		if (c->initialized && c->cpu_die_id == die_id &&
318 		    c->phys_proc_id == proc_id)
319 			return c->logical_die_id;
320 	}
321 	return -1;
322 }
323 EXPORT_SYMBOL(topology_phys_to_logical_die);
324 
325 /**
326  * topology_update_package_map - Update the physical to logical package map
327  * @pkg:	The physical package id as retrieved via CPUID
328  * @cpu:	The cpu for which this is updated
329  */
330 int topology_update_package_map(unsigned int pkg, unsigned int cpu)
331 {
332 	int new;
333 
334 	/* Already available somewhere? */
335 	new = topology_phys_to_logical_pkg(pkg);
336 	if (new >= 0)
337 		goto found;
338 
339 	new = logical_packages++;
340 	if (new != pkg) {
341 		pr_info("CPU %u Converting physical %u to logical package %u\n",
342 			cpu, pkg, new);
343 	}
344 found:
345 	cpu_data(cpu).logical_proc_id = new;
346 	return 0;
347 }
348 /**
349  * topology_update_die_map - Update the physical to logical die map
350  * @die:	The die id as retrieved via CPUID
351  * @cpu:	The cpu for which this is updated
352  */
353 int topology_update_die_map(unsigned int die, unsigned int cpu)
354 {
355 	int new;
356 
357 	/* Already available somewhere? */
358 	new = topology_phys_to_logical_die(die, cpu);
359 	if (new >= 0)
360 		goto found;
361 
362 	new = logical_die++;
363 	if (new != die) {
364 		pr_info("CPU %u Converting physical %u to logical die %u\n",
365 			cpu, die, new);
366 	}
367 found:
368 	cpu_data(cpu).logical_die_id = new;
369 	return 0;
370 }
371 
372 void __init smp_store_boot_cpu_info(void)
373 {
374 	int id = 0; /* CPU 0 */
375 	struct cpuinfo_x86 *c = &cpu_data(id);
376 
377 	*c = boot_cpu_data;
378 	c->cpu_index = id;
379 	topology_update_package_map(c->phys_proc_id, id);
380 	topology_update_die_map(c->cpu_die_id, id);
381 	c->initialized = true;
382 }
383 
384 /*
385  * The bootstrap kernel entry code has set these up. Save them for
386  * a given CPU
387  */
388 void smp_store_cpu_info(int id)
389 {
390 	struct cpuinfo_x86 *c = &cpu_data(id);
391 
392 	/* Copy boot_cpu_data only on the first bringup */
393 	if (!c->initialized)
394 		*c = boot_cpu_data;
395 	c->cpu_index = id;
396 	/*
397 	 * During boot time, CPU0 has this setup already. Save the info when
398 	 * bringing up AP or offlined CPU0.
399 	 */
400 	identify_secondary_cpu(c);
401 	c->initialized = true;
402 }
403 
404 static bool
405 topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
406 {
407 	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
408 
409 	return (cpu_to_node(cpu1) == cpu_to_node(cpu2));
410 }
411 
412 static bool
413 topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name)
414 {
415 	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
416 
417 	return !WARN_ONCE(!topology_same_node(c, o),
418 		"sched: CPU #%d's %s-sibling CPU #%d is not on the same node! "
419 		"[node: %d != %d]. Ignoring dependency.\n",
420 		cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2));
421 }
422 
423 #define link_mask(mfunc, c1, c2)					\
424 do {									\
425 	cpumask_set_cpu((c1), mfunc(c2));				\
426 	cpumask_set_cpu((c2), mfunc(c1));				\
427 } while (0)
428 
429 static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
430 {
431 	if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
432 		int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
433 
434 		if (c->phys_proc_id == o->phys_proc_id &&
435 		    c->cpu_die_id == o->cpu_die_id &&
436 		    per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
437 			if (c->cpu_core_id == o->cpu_core_id)
438 				return topology_sane(c, o, "smt");
439 
440 			if ((c->cu_id != 0xff) &&
441 			    (o->cu_id != 0xff) &&
442 			    (c->cu_id == o->cu_id))
443 				return topology_sane(c, o, "smt");
444 		}
445 
446 	} else if (c->phys_proc_id == o->phys_proc_id &&
447 		   c->cpu_die_id == o->cpu_die_id &&
448 		   c->cpu_core_id == o->cpu_core_id) {
449 		return topology_sane(c, o, "smt");
450 	}
451 
452 	return false;
453 }
454 
455 static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
456 {
457 	if (c->phys_proc_id == o->phys_proc_id &&
458 	    c->cpu_die_id == o->cpu_die_id)
459 		return true;
460 	return false;
461 }
462 
463 static bool match_l2c(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
464 {
465 	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
466 
467 	/* If the arch didn't set up l2c_id, fall back to SMT */
468 	if (per_cpu(cpu_l2c_id, cpu1) == BAD_APICID)
469 		return match_smt(c, o);
470 
471 	/* Do not match if L2 cache id does not match: */
472 	if (per_cpu(cpu_l2c_id, cpu1) != per_cpu(cpu_l2c_id, cpu2))
473 		return false;
474 
475 	return topology_sane(c, o, "l2c");
476 }
477 
478 /*
479  * Unlike the other levels, we do not enforce keeping a
480  * multicore group inside a NUMA node.  If this happens, we will
481  * discard the MC level of the topology later.
482  */
483 static bool match_pkg(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
484 {
485 	if (c->phys_proc_id == o->phys_proc_id)
486 		return true;
487 	return false;
488 }
489 
490 /*
491  * Define intel_cod_cpu[] for Intel COD (Cluster-on-Die) CPUs.
492  *
493  * Any Intel CPU that has multiple nodes per package and does not
494  * match intel_cod_cpu[] has the SNC (Sub-NUMA Cluster) topology.
495  *
496  * When in SNC mode, these CPUs enumerate an LLC that is shared
497  * by multiple NUMA nodes. The LLC is shared for off-package data
498  * access but private to the NUMA node (half of the package) for
499  * on-package access. CPUID (the source of the information about
500  * the LLC) can only enumerate the cache as shared or unshared,
501  * but not this particular configuration.
502  */
503 
504 static const struct x86_cpu_id intel_cod_cpu[] = {
505 	X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, 0),	/* COD */
506 	X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, 0),	/* COD */
507 	X86_MATCH_INTEL_FAM6_MODEL(ANY, 1),		/* SNC */
508 	{}
509 };
510 
511 static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
512 {
513 	const struct x86_cpu_id *id = x86_match_cpu(intel_cod_cpu);
514 	int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
515 	bool intel_snc = id && id->driver_data;
516 
517 	/* Do not match if we do not have a valid APICID for cpu: */
518 	if (per_cpu(cpu_llc_id, cpu1) == BAD_APICID)
519 		return false;
520 
521 	/* Do not match if LLC id does not match: */
522 	if (per_cpu(cpu_llc_id, cpu1) != per_cpu(cpu_llc_id, cpu2))
523 		return false;
524 
525 	/*
526 	 * Allow the SNC topology without warning. Return of false
527 	 * means 'c' does not share the LLC of 'o'. This will be
528 	 * reflected to userspace.
529 	 */
530 	if (match_pkg(c, o) && !topology_same_node(c, o) && intel_snc)
531 		return false;
532 
533 	return topology_sane(c, o, "llc");
534 }
535 
536 
537 #if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_CLUSTER) || defined(CONFIG_SCHED_MC)
538 static inline int x86_sched_itmt_flags(void)
539 {
540 	return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0;
541 }
542 
543 #ifdef CONFIG_SCHED_MC
544 static int x86_core_flags(void)
545 {
546 	return cpu_core_flags() | x86_sched_itmt_flags();
547 }
548 #endif
549 #ifdef CONFIG_SCHED_SMT
550 static int x86_smt_flags(void)
551 {
552 	return cpu_smt_flags() | x86_sched_itmt_flags();
553 }
554 #endif
555 #ifdef CONFIG_SCHED_CLUSTER
556 static int x86_cluster_flags(void)
557 {
558 	return cpu_cluster_flags() | x86_sched_itmt_flags();
559 }
560 #endif
561 #endif
562 
563 static struct sched_domain_topology_level x86_numa_in_package_topology[] = {
564 #ifdef CONFIG_SCHED_SMT
565 	{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
566 #endif
567 #ifdef CONFIG_SCHED_CLUSTER
568 	{ cpu_clustergroup_mask, x86_cluster_flags, SD_INIT_NAME(CLS) },
569 #endif
570 #ifdef CONFIG_SCHED_MC
571 	{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
572 #endif
573 	{ NULL, },
574 };
575 
576 static struct sched_domain_topology_level x86_hybrid_topology[] = {
577 #ifdef CONFIG_SCHED_SMT
578 	{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
579 #endif
580 #ifdef CONFIG_SCHED_MC
581 	{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
582 #endif
583 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
584 	{ NULL, },
585 };
586 
587 static struct sched_domain_topology_level x86_topology[] = {
588 #ifdef CONFIG_SCHED_SMT
589 	{ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
590 #endif
591 #ifdef CONFIG_SCHED_CLUSTER
592 	{ cpu_clustergroup_mask, x86_cluster_flags, SD_INIT_NAME(CLS) },
593 #endif
594 #ifdef CONFIG_SCHED_MC
595 	{ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
596 #endif
597 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
598 	{ NULL, },
599 };
600 
601 /*
602  * Set if a package/die has multiple NUMA nodes inside.
603  * AMD Magny-Cours, Intel Cluster-on-Die, and Intel
604  * Sub-NUMA Clustering have this.
605  */
606 static bool x86_has_numa_in_package;
607 
608 void set_cpu_sibling_map(int cpu)
609 {
610 	bool has_smt = smp_num_siblings > 1;
611 	bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
612 	struct cpuinfo_x86 *c = &cpu_data(cpu);
613 	struct cpuinfo_x86 *o;
614 	int i, threads;
615 
616 	cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
617 
618 	if (!has_mp) {
619 		cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu));
620 		cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
621 		cpumask_set_cpu(cpu, cpu_l2c_shared_mask(cpu));
622 		cpumask_set_cpu(cpu, topology_core_cpumask(cpu));
623 		cpumask_set_cpu(cpu, topology_die_cpumask(cpu));
624 		c->booted_cores = 1;
625 		return;
626 	}
627 
628 	for_each_cpu(i, cpu_sibling_setup_mask) {
629 		o = &cpu_data(i);
630 
631 		if (match_pkg(c, o) && !topology_same_node(c, o))
632 			x86_has_numa_in_package = true;
633 
634 		if ((i == cpu) || (has_smt && match_smt(c, o)))
635 			link_mask(topology_sibling_cpumask, cpu, i);
636 
637 		if ((i == cpu) || (has_mp && match_llc(c, o)))
638 			link_mask(cpu_llc_shared_mask, cpu, i);
639 
640 		if ((i == cpu) || (has_mp && match_l2c(c, o)))
641 			link_mask(cpu_l2c_shared_mask, cpu, i);
642 
643 		if ((i == cpu) || (has_mp && match_die(c, o)))
644 			link_mask(topology_die_cpumask, cpu, i);
645 	}
646 
647 	threads = cpumask_weight(topology_sibling_cpumask(cpu));
648 	if (threads > __max_smt_threads)
649 		__max_smt_threads = threads;
650 
651 	for_each_cpu(i, topology_sibling_cpumask(cpu))
652 		cpu_data(i).smt_active = threads > 1;
653 
654 	/*
655 	 * This needs a separate iteration over the cpus because we rely on all
656 	 * topology_sibling_cpumask links to be set-up.
657 	 */
658 	for_each_cpu(i, cpu_sibling_setup_mask) {
659 		o = &cpu_data(i);
660 
661 		if ((i == cpu) || (has_mp && match_pkg(c, o))) {
662 			link_mask(topology_core_cpumask, cpu, i);
663 
664 			/*
665 			 *  Does this new cpu bringup a new core?
666 			 */
667 			if (threads == 1) {
668 				/*
669 				 * for each core in package, increment
670 				 * the booted_cores for this new cpu
671 				 */
672 				if (cpumask_first(
673 				    topology_sibling_cpumask(i)) == i)
674 					c->booted_cores++;
675 				/*
676 				 * increment the core count for all
677 				 * the other cpus in this package
678 				 */
679 				if (i != cpu)
680 					cpu_data(i).booted_cores++;
681 			} else if (i != cpu && !c->booted_cores)
682 				c->booted_cores = cpu_data(i).booted_cores;
683 		}
684 	}
685 }
686 
687 /* maps the cpu to the sched domain representing multi-core */
688 const struct cpumask *cpu_coregroup_mask(int cpu)
689 {
690 	return cpu_llc_shared_mask(cpu);
691 }
692 
693 const struct cpumask *cpu_clustergroup_mask(int cpu)
694 {
695 	return cpu_l2c_shared_mask(cpu);
696 }
697 
698 static void impress_friends(void)
699 {
700 	int cpu;
701 	unsigned long bogosum = 0;
702 	/*
703 	 * Allow the user to impress friends.
704 	 */
705 	pr_debug("Before bogomips\n");
706 	for_each_possible_cpu(cpu)
707 		if (cpumask_test_cpu(cpu, cpu_callout_mask))
708 			bogosum += cpu_data(cpu).loops_per_jiffy;
709 	pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n",
710 		num_online_cpus(),
711 		bogosum/(500000/HZ),
712 		(bogosum/(5000/HZ))%100);
713 
714 	pr_debug("Before bogocount - setting activated=1\n");
715 }
716 
717 void __inquire_remote_apic(int apicid)
718 {
719 	unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
720 	const char * const names[] = { "ID", "VERSION", "SPIV" };
721 	int timeout;
722 	u32 status;
723 
724 	pr_info("Inquiring remote APIC 0x%x...\n", apicid);
725 
726 	for (i = 0; i < ARRAY_SIZE(regs); i++) {
727 		pr_info("... APIC 0x%x %s: ", apicid, names[i]);
728 
729 		/*
730 		 * Wait for idle.
731 		 */
732 		status = safe_apic_wait_icr_idle();
733 		if (status)
734 			pr_cont("a previous APIC delivery may have failed\n");
735 
736 		apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
737 
738 		timeout = 0;
739 		do {
740 			udelay(100);
741 			status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
742 		} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
743 
744 		switch (status) {
745 		case APIC_ICR_RR_VALID:
746 			status = apic_read(APIC_RRR);
747 			pr_cont("%08x\n", status);
748 			break;
749 		default:
750 			pr_cont("failed\n");
751 		}
752 	}
753 }
754 
755 /*
756  * The Multiprocessor Specification 1.4 (1997) example code suggests
757  * that there should be a 10ms delay between the BSP asserting INIT
758  * and de-asserting INIT, when starting a remote processor.
759  * But that slows boot and resume on modern processors, which include
760  * many cores and don't require that delay.
761  *
762  * Cmdline "init_cpu_udelay=" is available to over-ride this delay.
763  * Modern processor families are quirked to remove the delay entirely.
764  */
765 #define UDELAY_10MS_DEFAULT 10000
766 
767 static unsigned int init_udelay = UINT_MAX;
768 
769 static int __init cpu_init_udelay(char *str)
770 {
771 	get_option(&str, &init_udelay);
772 
773 	return 0;
774 }
775 early_param("cpu_init_udelay", cpu_init_udelay);
776 
777 static void __init smp_quirk_init_udelay(void)
778 {
779 	/* if cmdline changed it from default, leave it alone */
780 	if (init_udelay != UINT_MAX)
781 		return;
782 
783 	/* if modern processor, use no delay */
784 	if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
785 	    ((boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) && (boot_cpu_data.x86 >= 0x18)) ||
786 	    ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
787 		init_udelay = 0;
788 		return;
789 	}
790 	/* else, use legacy delay */
791 	init_udelay = UDELAY_10MS_DEFAULT;
792 }
793 
794 /*
795  * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
796  * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
797  * won't ... remember to clear down the APIC, etc later.
798  */
799 int
800 wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
801 {
802 	u32 dm = apic->dest_mode_logical ? APIC_DEST_LOGICAL : APIC_DEST_PHYSICAL;
803 	unsigned long send_status, accept_status = 0;
804 	int maxlvt;
805 
806 	/* Target chip */
807 	/* Boot on the stack */
808 	/* Kick the second */
809 	apic_icr_write(APIC_DM_NMI | dm, apicid);
810 
811 	pr_debug("Waiting for send to finish...\n");
812 	send_status = safe_apic_wait_icr_idle();
813 
814 	/*
815 	 * Give the other CPU some time to accept the IPI.
816 	 */
817 	udelay(200);
818 	if (APIC_INTEGRATED(boot_cpu_apic_version)) {
819 		maxlvt = lapic_get_maxlvt();
820 		if (maxlvt > 3)			/* Due to the Pentium erratum 3AP.  */
821 			apic_write(APIC_ESR, 0);
822 		accept_status = (apic_read(APIC_ESR) & 0xEF);
823 	}
824 	pr_debug("NMI sent\n");
825 
826 	if (send_status)
827 		pr_err("APIC never delivered???\n");
828 	if (accept_status)
829 		pr_err("APIC delivery error (%lx)\n", accept_status);
830 
831 	return (send_status | accept_status);
832 }
833 
834 static int
835 wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
836 {
837 	unsigned long send_status = 0, accept_status = 0;
838 	int maxlvt, num_starts, j;
839 
840 	maxlvt = lapic_get_maxlvt();
841 
842 	/*
843 	 * Be paranoid about clearing APIC errors.
844 	 */
845 	if (APIC_INTEGRATED(boot_cpu_apic_version)) {
846 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
847 			apic_write(APIC_ESR, 0);
848 		apic_read(APIC_ESR);
849 	}
850 
851 	pr_debug("Asserting INIT\n");
852 
853 	/*
854 	 * Turn INIT on target chip
855 	 */
856 	/*
857 	 * Send IPI
858 	 */
859 	apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
860 		       phys_apicid);
861 
862 	pr_debug("Waiting for send to finish...\n");
863 	send_status = safe_apic_wait_icr_idle();
864 
865 	udelay(init_udelay);
866 
867 	pr_debug("Deasserting INIT\n");
868 
869 	/* Target chip */
870 	/* Send IPI */
871 	apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
872 
873 	pr_debug("Waiting for send to finish...\n");
874 	send_status = safe_apic_wait_icr_idle();
875 
876 	mb();
877 
878 	/*
879 	 * Should we send STARTUP IPIs ?
880 	 *
881 	 * Determine this based on the APIC version.
882 	 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
883 	 */
884 	if (APIC_INTEGRATED(boot_cpu_apic_version))
885 		num_starts = 2;
886 	else
887 		num_starts = 0;
888 
889 	/*
890 	 * Run STARTUP IPI loop.
891 	 */
892 	pr_debug("#startup loops: %d\n", num_starts);
893 
894 	for (j = 1; j <= num_starts; j++) {
895 		pr_debug("Sending STARTUP #%d\n", j);
896 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
897 			apic_write(APIC_ESR, 0);
898 		apic_read(APIC_ESR);
899 		pr_debug("After apic_write\n");
900 
901 		/*
902 		 * STARTUP IPI
903 		 */
904 
905 		/* Target chip */
906 		/* Boot on the stack */
907 		/* Kick the second */
908 		apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
909 			       phys_apicid);
910 
911 		/*
912 		 * Give the other CPU some time to accept the IPI.
913 		 */
914 		if (init_udelay == 0)
915 			udelay(10);
916 		else
917 			udelay(300);
918 
919 		pr_debug("Startup point 1\n");
920 
921 		pr_debug("Waiting for send to finish...\n");
922 		send_status = safe_apic_wait_icr_idle();
923 
924 		/*
925 		 * Give the other CPU some time to accept the IPI.
926 		 */
927 		if (init_udelay == 0)
928 			udelay(10);
929 		else
930 			udelay(200);
931 
932 		if (maxlvt > 3)		/* Due to the Pentium erratum 3AP.  */
933 			apic_write(APIC_ESR, 0);
934 		accept_status = (apic_read(APIC_ESR) & 0xEF);
935 		if (send_status || accept_status)
936 			break;
937 	}
938 	pr_debug("After Startup\n");
939 
940 	if (send_status)
941 		pr_err("APIC never delivered???\n");
942 	if (accept_status)
943 		pr_err("APIC delivery error (%lx)\n", accept_status);
944 
945 	return (send_status | accept_status);
946 }
947 
948 /* reduce the number of lines printed when booting a large cpu count system */
949 static void announce_cpu(int cpu, int apicid)
950 {
951 	static int current_node = NUMA_NO_NODE;
952 	int node = early_cpu_to_node(cpu);
953 	static int width, node_width;
954 
955 	if (!width)
956 		width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */
957 
958 	if (!node_width)
959 		node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */
960 
961 	if (cpu == 1)
962 		printk(KERN_INFO "x86: Booting SMP configuration:\n");
963 
964 	if (system_state < SYSTEM_RUNNING) {
965 		if (node != current_node) {
966 			if (current_node > (-1))
967 				pr_cont("\n");
968 			current_node = node;
969 
970 			printk(KERN_INFO ".... node %*s#%d, CPUs:  ",
971 			       node_width - num_digits(node), " ", node);
972 		}
973 
974 		/* Add padding for the BSP */
975 		if (cpu == 1)
976 			pr_cont("%*s", width + 1, " ");
977 
978 		pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);
979 
980 	} else
981 		pr_info("Booting Node %d Processor %d APIC 0x%x\n",
982 			node, cpu, apicid);
983 }
984 
985 static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs)
986 {
987 	int cpu;
988 
989 	cpu = smp_processor_id();
990 	if (cpu == 0 && !cpu_online(cpu) && enable_start_cpu0)
991 		return NMI_HANDLED;
992 
993 	return NMI_DONE;
994 }
995 
996 /*
997  * Wake up AP by INIT, INIT, STARTUP sequence.
998  *
999  * Instead of waiting for STARTUP after INITs, BSP will execute the BIOS
1000  * boot-strap code which is not a desired behavior for waking up BSP. To
1001  * void the boot-strap code, wake up CPU0 by NMI instead.
1002  *
1003  * This works to wake up soft offlined CPU0 only. If CPU0 is hard offlined
1004  * (i.e. physically hot removed and then hot added), NMI won't wake it up.
1005  * We'll change this code in the future to wake up hard offlined CPU0 if
1006  * real platform and request are available.
1007  */
1008 static int
1009 wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
1010 	       int *cpu0_nmi_registered)
1011 {
1012 	int id;
1013 	int boot_error;
1014 
1015 	preempt_disable();
1016 
1017 	/*
1018 	 * Wake up AP by INIT, INIT, STARTUP sequence.
1019 	 */
1020 	if (cpu) {
1021 		boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
1022 		goto out;
1023 	}
1024 
1025 	/*
1026 	 * Wake up BSP by nmi.
1027 	 *
1028 	 * Register a NMI handler to help wake up CPU0.
1029 	 */
1030 	boot_error = register_nmi_handler(NMI_LOCAL,
1031 					  wakeup_cpu0_nmi, 0, "wake_cpu0");
1032 
1033 	if (!boot_error) {
1034 		enable_start_cpu0 = 1;
1035 		*cpu0_nmi_registered = 1;
1036 		id = apic->dest_mode_logical ? cpu0_logical_apicid : apicid;
1037 		boot_error = wakeup_secondary_cpu_via_nmi(id, start_ip);
1038 	}
1039 
1040 out:
1041 	preempt_enable();
1042 
1043 	return boot_error;
1044 }
1045 
1046 int common_cpu_up(unsigned int cpu, struct task_struct *idle)
1047 {
1048 	int ret;
1049 
1050 	/* Just in case we booted with a single CPU. */
1051 	alternatives_enable_smp();
1052 
1053 	per_cpu(current_task, cpu) = idle;
1054 	cpu_init_stack_canary(cpu, idle);
1055 
1056 	/* Initialize the interrupt stack(s) */
1057 	ret = irq_init_percpu_irqstack(cpu);
1058 	if (ret)
1059 		return ret;
1060 
1061 #ifdef CONFIG_X86_32
1062 	/* Stack for startup_32 can be just as for start_secondary onwards */
1063 	per_cpu(cpu_current_top_of_stack, cpu) = task_top_of_stack(idle);
1064 #else
1065 	initial_gs = per_cpu_offset(cpu);
1066 #endif
1067 	return 0;
1068 }
1069 
1070 /*
1071  * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
1072  * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
1073  * Returns zero if CPU booted OK, else error code from
1074  * ->wakeup_secondary_cpu.
1075  */
1076 static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle,
1077 		       int *cpu0_nmi_registered)
1078 {
1079 	/* start_ip had better be page-aligned! */
1080 	unsigned long start_ip = real_mode_header->trampoline_start;
1081 
1082 	unsigned long boot_error = 0;
1083 	unsigned long timeout;
1084 
1085 #ifdef CONFIG_X86_64
1086 	/* If 64-bit wakeup method exists, use the 64-bit mode trampoline IP */
1087 	if (apic->wakeup_secondary_cpu_64)
1088 		start_ip = real_mode_header->trampoline_start64;
1089 #endif
1090 	idle->thread.sp = (unsigned long)task_pt_regs(idle);
1091 	early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu);
1092 	initial_code = (unsigned long)start_secondary;
1093 	initial_stack  = idle->thread.sp;
1094 
1095 	/* Enable the espfix hack for this CPU */
1096 	init_espfix_ap(cpu);
1097 
1098 	/* So we see what's up */
1099 	announce_cpu(cpu, apicid);
1100 
1101 	/*
1102 	 * This grunge runs the startup process for
1103 	 * the targeted processor.
1104 	 */
1105 
1106 	if (x86_platform.legacy.warm_reset) {
1107 
1108 		pr_debug("Setting warm reset code and vector.\n");
1109 
1110 		smpboot_setup_warm_reset_vector(start_ip);
1111 		/*
1112 		 * Be paranoid about clearing APIC errors.
1113 		*/
1114 		if (APIC_INTEGRATED(boot_cpu_apic_version)) {
1115 			apic_write(APIC_ESR, 0);
1116 			apic_read(APIC_ESR);
1117 		}
1118 	}
1119 
1120 	/*
1121 	 * AP might wait on cpu_callout_mask in cpu_init() with
1122 	 * cpu_initialized_mask set if previous attempt to online
1123 	 * it timed-out. Clear cpu_initialized_mask so that after
1124 	 * INIT/SIPI it could start with a clean state.
1125 	 */
1126 	cpumask_clear_cpu(cpu, cpu_initialized_mask);
1127 	smp_mb();
1128 
1129 	/*
1130 	 * Wake up a CPU in difference cases:
1131 	 * - Use a method from the APIC driver if one defined, with wakeup
1132 	 *   straight to 64-bit mode preferred over wakeup to RM.
1133 	 * Otherwise,
1134 	 * - Use an INIT boot APIC message for APs or NMI for BSP.
1135 	 */
1136 	if (apic->wakeup_secondary_cpu_64)
1137 		boot_error = apic->wakeup_secondary_cpu_64(apicid, start_ip);
1138 	else if (apic->wakeup_secondary_cpu)
1139 		boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
1140 	else
1141 		boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid,
1142 						     cpu0_nmi_registered);
1143 
1144 	if (!boot_error) {
1145 		/*
1146 		 * Wait 10s total for first sign of life from AP
1147 		 */
1148 		boot_error = -1;
1149 		timeout = jiffies + 10*HZ;
1150 		while (time_before(jiffies, timeout)) {
1151 			if (cpumask_test_cpu(cpu, cpu_initialized_mask)) {
1152 				/*
1153 				 * Tell AP to proceed with initialization
1154 				 */
1155 				cpumask_set_cpu(cpu, cpu_callout_mask);
1156 				boot_error = 0;
1157 				break;
1158 			}
1159 			schedule();
1160 		}
1161 	}
1162 
1163 	if (!boot_error) {
1164 		/*
1165 		 * Wait till AP completes initial initialization
1166 		 */
1167 		while (!cpumask_test_cpu(cpu, cpu_callin_mask)) {
1168 			/*
1169 			 * Allow other tasks to run while we wait for the
1170 			 * AP to come online. This also gives a chance
1171 			 * for the MTRR work(triggered by the AP coming online)
1172 			 * to be completed in the stop machine context.
1173 			 */
1174 			schedule();
1175 		}
1176 	}
1177 
1178 	if (x86_platform.legacy.warm_reset) {
1179 		/*
1180 		 * Cleanup possible dangling ends...
1181 		 */
1182 		smpboot_restore_warm_reset_vector();
1183 	}
1184 
1185 	return boot_error;
1186 }
1187 
1188 int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
1189 {
1190 	int apicid = apic->cpu_present_to_apicid(cpu);
1191 	int cpu0_nmi_registered = 0;
1192 	unsigned long flags;
1193 	int err, ret = 0;
1194 
1195 	lockdep_assert_irqs_enabled();
1196 
1197 	pr_debug("++++++++++++++++++++=_---CPU UP  %u\n", cpu);
1198 
1199 	if (apicid == BAD_APICID ||
1200 	    !physid_isset(apicid, phys_cpu_present_map) ||
1201 	    !apic->apic_id_valid(apicid)) {
1202 		pr_err("%s: bad cpu %d\n", __func__, cpu);
1203 		return -EINVAL;
1204 	}
1205 
1206 	/*
1207 	 * Already booted CPU?
1208 	 */
1209 	if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
1210 		pr_debug("do_boot_cpu %d Already started\n", cpu);
1211 		return -ENOSYS;
1212 	}
1213 
1214 	/*
1215 	 * Save current MTRR state in case it was changed since early boot
1216 	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
1217 	 */
1218 	mtrr_save_state();
1219 
1220 	/* x86 CPUs take themselves offline, so delayed offline is OK. */
1221 	err = cpu_check_up_prepare(cpu);
1222 	if (err && err != -EBUSY)
1223 		return err;
1224 
1225 	/* the FPU context is blank, nobody can own it */
1226 	per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL;
1227 
1228 	err = common_cpu_up(cpu, tidle);
1229 	if (err)
1230 		return err;
1231 
1232 	err = do_boot_cpu(apicid, cpu, tidle, &cpu0_nmi_registered);
1233 	if (err) {
1234 		pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
1235 		ret = -EIO;
1236 		goto unreg_nmi;
1237 	}
1238 
1239 	/*
1240 	 * Check TSC synchronization with the AP (keep irqs disabled
1241 	 * while doing so):
1242 	 */
1243 	local_irq_save(flags);
1244 	check_tsc_sync_source(cpu);
1245 	local_irq_restore(flags);
1246 
1247 	while (!cpu_online(cpu)) {
1248 		cpu_relax();
1249 		touch_nmi_watchdog();
1250 	}
1251 
1252 unreg_nmi:
1253 	/*
1254 	 * Clean up the nmi handler. Do this after the callin and callout sync
1255 	 * to avoid impact of possible long unregister time.
1256 	 */
1257 	if (cpu0_nmi_registered)
1258 		unregister_nmi_handler(NMI_LOCAL, "wake_cpu0");
1259 
1260 	return ret;
1261 }
1262 
1263 /**
1264  * arch_disable_smp_support() - disables SMP support for x86 at runtime
1265  */
1266 void arch_disable_smp_support(void)
1267 {
1268 	disable_ioapic_support();
1269 }
1270 
1271 /*
1272  * Fall back to non SMP mode after errors.
1273  *
1274  * RED-PEN audit/test this more. I bet there is more state messed up here.
1275  */
1276 static __init void disable_smp(void)
1277 {
1278 	pr_info("SMP disabled\n");
1279 
1280 	disable_ioapic_support();
1281 
1282 	init_cpu_present(cpumask_of(0));
1283 	init_cpu_possible(cpumask_of(0));
1284 
1285 	if (smp_found_config)
1286 		physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
1287 	else
1288 		physid_set_mask_of_physid(0, &phys_cpu_present_map);
1289 	cpumask_set_cpu(0, topology_sibling_cpumask(0));
1290 	cpumask_set_cpu(0, topology_core_cpumask(0));
1291 	cpumask_set_cpu(0, topology_die_cpumask(0));
1292 }
1293 
1294 /*
1295  * Various sanity checks.
1296  */
1297 static void __init smp_sanity_check(void)
1298 {
1299 	preempt_disable();
1300 
1301 #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
1302 	if (def_to_bigsmp && nr_cpu_ids > 8) {
1303 		unsigned int cpu;
1304 		unsigned nr;
1305 
1306 		pr_warn("More than 8 CPUs detected - skipping them\n"
1307 			"Use CONFIG_X86_BIGSMP\n");
1308 
1309 		nr = 0;
1310 		for_each_present_cpu(cpu) {
1311 			if (nr >= 8)
1312 				set_cpu_present(cpu, false);
1313 			nr++;
1314 		}
1315 
1316 		nr = 0;
1317 		for_each_possible_cpu(cpu) {
1318 			if (nr >= 8)
1319 				set_cpu_possible(cpu, false);
1320 			nr++;
1321 		}
1322 
1323 		nr_cpu_ids = 8;
1324 	}
1325 #endif
1326 
1327 	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
1328 		pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n",
1329 			hard_smp_processor_id());
1330 
1331 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
1332 	}
1333 
1334 	/*
1335 	 * Should not be necessary because the MP table should list the boot
1336 	 * CPU too, but we do it for the sake of robustness anyway.
1337 	 */
1338 	if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
1339 		pr_notice("weird, boot CPU (#%d) not listed by the BIOS\n",
1340 			  boot_cpu_physical_apicid);
1341 		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
1342 	}
1343 	preempt_enable();
1344 }
1345 
1346 static void __init smp_cpu_index_default(void)
1347 {
1348 	int i;
1349 	struct cpuinfo_x86 *c;
1350 
1351 	for_each_possible_cpu(i) {
1352 		c = &cpu_data(i);
1353 		/* mark all to hotplug */
1354 		c->cpu_index = nr_cpu_ids;
1355 	}
1356 }
1357 
1358 static void __init smp_get_logical_apicid(void)
1359 {
1360 	if (x2apic_mode)
1361 		cpu0_logical_apicid = apic_read(APIC_LDR);
1362 	else
1363 		cpu0_logical_apicid = GET_APIC_LOGICAL_ID(apic_read(APIC_LDR));
1364 }
1365 
1366 void __init smp_prepare_cpus_common(void)
1367 {
1368 	unsigned int i;
1369 
1370 	smp_cpu_index_default();
1371 
1372 	/*
1373 	 * Setup boot CPU information
1374 	 */
1375 	smp_store_boot_cpu_info(); /* Final full version of the data */
1376 	cpumask_copy(cpu_callin_mask, cpumask_of(0));
1377 	mb();
1378 
1379 	for_each_possible_cpu(i) {
1380 		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
1381 		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
1382 		zalloc_cpumask_var(&per_cpu(cpu_die_map, i), GFP_KERNEL);
1383 		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
1384 		zalloc_cpumask_var(&per_cpu(cpu_l2c_shared_map, i), GFP_KERNEL);
1385 	}
1386 
1387 	/*
1388 	 * Set 'default' x86 topology, this matches default_topology() in that
1389 	 * it has NUMA nodes as a topology level. See also
1390 	 * native_smp_cpus_done().
1391 	 *
1392 	 * Must be done before set_cpus_sibling_map() is ran.
1393 	 */
1394 	set_sched_topology(x86_topology);
1395 
1396 	set_cpu_sibling_map(0);
1397 }
1398 
1399 /*
1400  * Prepare for SMP bootup.
1401  * @max_cpus: configured maximum number of CPUs, It is a legacy parameter
1402  *            for common interface support.
1403  */
1404 void __init native_smp_prepare_cpus(unsigned int max_cpus)
1405 {
1406 	smp_prepare_cpus_common();
1407 
1408 	smp_sanity_check();
1409 
1410 	switch (apic_intr_mode) {
1411 	case APIC_PIC:
1412 	case APIC_VIRTUAL_WIRE_NO_CONFIG:
1413 		disable_smp();
1414 		return;
1415 	case APIC_SYMMETRIC_IO_NO_ROUTING:
1416 		disable_smp();
1417 		/* Setup local timer */
1418 		x86_init.timers.setup_percpu_clockev();
1419 		return;
1420 	case APIC_VIRTUAL_WIRE:
1421 	case APIC_SYMMETRIC_IO:
1422 		break;
1423 	}
1424 
1425 	/* Setup local timer */
1426 	x86_init.timers.setup_percpu_clockev();
1427 
1428 	smp_get_logical_apicid();
1429 
1430 	pr_info("CPU0: ");
1431 	print_cpu_info(&cpu_data(0));
1432 
1433 	uv_system_init();
1434 
1435 	set_mtrr_aps_delayed_init();
1436 
1437 	smp_quirk_init_udelay();
1438 
1439 	speculative_store_bypass_ht_init();
1440 
1441 	snp_set_wakeup_secondary_cpu();
1442 }
1443 
1444 void arch_thaw_secondary_cpus_begin(void)
1445 {
1446 	set_mtrr_aps_delayed_init();
1447 }
1448 
1449 void arch_thaw_secondary_cpus_end(void)
1450 {
1451 	mtrr_aps_init();
1452 }
1453 
1454 /*
1455  * Early setup to make printk work.
1456  */
1457 void __init native_smp_prepare_boot_cpu(void)
1458 {
1459 	int me = smp_processor_id();
1460 	switch_to_new_gdt(me);
1461 	/* already set me in cpu_online_mask in boot_cpu_init() */
1462 	cpumask_set_cpu(me, cpu_callout_mask);
1463 	cpu_set_state_online(me);
1464 	native_pv_lock_init();
1465 }
1466 
1467 void __init calculate_max_logical_packages(void)
1468 {
1469 	int ncpus;
1470 
1471 	/*
1472 	 * Today neither Intel nor AMD support heterogeneous systems so
1473 	 * extrapolate the boot cpu's data to all packages.
1474 	 */
1475 	ncpus = cpu_data(0).booted_cores * topology_max_smt_threads();
1476 	__max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
1477 	pr_info("Max logical packages: %u\n", __max_logical_packages);
1478 }
1479 
1480 void __init native_smp_cpus_done(unsigned int max_cpus)
1481 {
1482 	pr_debug("Boot done\n");
1483 
1484 	calculate_max_logical_packages();
1485 
1486 	/* XXX for now assume numa-in-package and hybrid don't overlap */
1487 	if (x86_has_numa_in_package)
1488 		set_sched_topology(x86_numa_in_package_topology);
1489 	if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
1490 		set_sched_topology(x86_hybrid_topology);
1491 
1492 	nmi_selftest();
1493 	impress_friends();
1494 	mtrr_aps_init();
1495 }
1496 
1497 static int __initdata setup_possible_cpus = -1;
1498 static int __init _setup_possible_cpus(char *str)
1499 {
1500 	get_option(&str, &setup_possible_cpus);
1501 	return 0;
1502 }
1503 early_param("possible_cpus", _setup_possible_cpus);
1504 
1505 
1506 /*
1507  * cpu_possible_mask should be static, it cannot change as cpu's
1508  * are onlined, or offlined. The reason is per-cpu data-structures
1509  * are allocated by some modules at init time, and don't expect to
1510  * do this dynamically on cpu arrival/departure.
1511  * cpu_present_mask on the other hand can change dynamically.
1512  * In case when cpu_hotplug is not compiled, then we resort to current
1513  * behaviour, which is cpu_possible == cpu_present.
1514  * - Ashok Raj
1515  *
1516  * Three ways to find out the number of additional hotplug CPUs:
1517  * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
1518  * - The user can overwrite it with possible_cpus=NUM
1519  * - Otherwise don't reserve additional CPUs.
1520  * We do this because additional CPUs waste a lot of memory.
1521  * -AK
1522  */
1523 __init void prefill_possible_map(void)
1524 {
1525 	int i, possible;
1526 
1527 	/* No boot processor was found in mptable or ACPI MADT */
1528 	if (!num_processors) {
1529 		if (boot_cpu_has(X86_FEATURE_APIC)) {
1530 			int apicid = boot_cpu_physical_apicid;
1531 			int cpu = hard_smp_processor_id();
1532 
1533 			pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
1534 
1535 			/* Make sure boot cpu is enumerated */
1536 			if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
1537 			    apic->apic_id_valid(apicid))
1538 				generic_processor_info(apicid, boot_cpu_apic_version);
1539 		}
1540 
1541 		if (!num_processors)
1542 			num_processors = 1;
1543 	}
1544 
1545 	i = setup_max_cpus ?: 1;
1546 	if (setup_possible_cpus == -1) {
1547 		possible = num_processors;
1548 #ifdef CONFIG_HOTPLUG_CPU
1549 		if (setup_max_cpus)
1550 			possible += disabled_cpus;
1551 #else
1552 		if (possible > i)
1553 			possible = i;
1554 #endif
1555 	} else
1556 		possible = setup_possible_cpus;
1557 
1558 	total_cpus = max_t(int, possible, num_processors + disabled_cpus);
1559 
1560 	/* nr_cpu_ids could be reduced via nr_cpus= */
1561 	if (possible > nr_cpu_ids) {
1562 		pr_warn("%d Processors exceeds NR_CPUS limit of %u\n",
1563 			possible, nr_cpu_ids);
1564 		possible = nr_cpu_ids;
1565 	}
1566 
1567 #ifdef CONFIG_HOTPLUG_CPU
1568 	if (!setup_max_cpus)
1569 #endif
1570 	if (possible > i) {
1571 		pr_warn("%d Processors exceeds max_cpus limit of %u\n",
1572 			possible, setup_max_cpus);
1573 		possible = i;
1574 	}
1575 
1576 	nr_cpu_ids = possible;
1577 
1578 	pr_info("Allowing %d CPUs, %d hotplug CPUs\n",
1579 		possible, max_t(int, possible - num_processors, 0));
1580 
1581 	reset_cpu_possible_mask();
1582 
1583 	for (i = 0; i < possible; i++)
1584 		set_cpu_possible(i, true);
1585 }
1586 
1587 #ifdef CONFIG_HOTPLUG_CPU
1588 
1589 /* Recompute SMT state for all CPUs on offline */
1590 static void recompute_smt_state(void)
1591 {
1592 	int max_threads, cpu;
1593 
1594 	max_threads = 0;
1595 	for_each_online_cpu (cpu) {
1596 		int threads = cpumask_weight(topology_sibling_cpumask(cpu));
1597 
1598 		if (threads > max_threads)
1599 			max_threads = threads;
1600 	}
1601 	__max_smt_threads = max_threads;
1602 }
1603 
1604 static void remove_siblinginfo(int cpu)
1605 {
1606 	int sibling;
1607 	struct cpuinfo_x86 *c = &cpu_data(cpu);
1608 
1609 	for_each_cpu(sibling, topology_core_cpumask(cpu)) {
1610 		cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
1611 		/*/
1612 		 * last thread sibling in this cpu core going down
1613 		 */
1614 		if (cpumask_weight(topology_sibling_cpumask(cpu)) == 1)
1615 			cpu_data(sibling).booted_cores--;
1616 	}
1617 
1618 	for_each_cpu(sibling, topology_die_cpumask(cpu))
1619 		cpumask_clear_cpu(cpu, topology_die_cpumask(sibling));
1620 
1621 	for_each_cpu(sibling, topology_sibling_cpumask(cpu)) {
1622 		cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
1623 		if (cpumask_weight(topology_sibling_cpumask(sibling)) == 1)
1624 			cpu_data(sibling).smt_active = false;
1625 	}
1626 
1627 	for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
1628 		cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
1629 	for_each_cpu(sibling, cpu_l2c_shared_mask(cpu))
1630 		cpumask_clear_cpu(cpu, cpu_l2c_shared_mask(sibling));
1631 	cpumask_clear(cpu_llc_shared_mask(cpu));
1632 	cpumask_clear(cpu_l2c_shared_mask(cpu));
1633 	cpumask_clear(topology_sibling_cpumask(cpu));
1634 	cpumask_clear(topology_core_cpumask(cpu));
1635 	cpumask_clear(topology_die_cpumask(cpu));
1636 	c->cpu_core_id = 0;
1637 	c->booted_cores = 0;
1638 	cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
1639 	recompute_smt_state();
1640 }
1641 
1642 static void remove_cpu_from_maps(int cpu)
1643 {
1644 	set_cpu_online(cpu, false);
1645 	cpumask_clear_cpu(cpu, cpu_callout_mask);
1646 	cpumask_clear_cpu(cpu, cpu_callin_mask);
1647 	/* was set by cpu_init() */
1648 	cpumask_clear_cpu(cpu, cpu_initialized_mask);
1649 	numa_remove_cpu(cpu);
1650 }
1651 
1652 void cpu_disable_common(void)
1653 {
1654 	int cpu = smp_processor_id();
1655 
1656 	remove_siblinginfo(cpu);
1657 
1658 	/* It's now safe to remove this processor from the online map */
1659 	lock_vector_lock();
1660 	remove_cpu_from_maps(cpu);
1661 	unlock_vector_lock();
1662 	fixup_irqs();
1663 	lapic_offline();
1664 }
1665 
1666 int native_cpu_disable(void)
1667 {
1668 	int ret;
1669 
1670 	ret = lapic_can_unplug_cpu();
1671 	if (ret)
1672 		return ret;
1673 
1674 	cpu_disable_common();
1675 
1676         /*
1677          * Disable the local APIC. Otherwise IPI broadcasts will reach
1678          * it. It still responds normally to INIT, NMI, SMI, and SIPI
1679          * messages.
1680          *
1681          * Disabling the APIC must happen after cpu_disable_common()
1682          * which invokes fixup_irqs().
1683          *
1684          * Disabling the APIC preserves already set bits in IRR, but
1685          * an interrupt arriving after disabling the local APIC does not
1686          * set the corresponding IRR bit.
1687          *
1688          * fixup_irqs() scans IRR for set bits so it can raise a not
1689          * yet handled interrupt on the new destination CPU via an IPI
1690          * but obviously it can't do so for IRR bits which are not set.
1691          * IOW, interrupts arriving after disabling the local APIC will
1692          * be lost.
1693          */
1694 	apic_soft_disable();
1695 
1696 	return 0;
1697 }
1698 
1699 int common_cpu_die(unsigned int cpu)
1700 {
1701 	int ret = 0;
1702 
1703 	/* We don't do anything here: idle task is faking death itself. */
1704 
1705 	/* They ack this in play_dead() by setting CPU_DEAD */
1706 	if (cpu_wait_death(cpu, 5)) {
1707 		if (system_state == SYSTEM_RUNNING)
1708 			pr_info("CPU %u is now offline\n", cpu);
1709 	} else {
1710 		pr_err("CPU %u didn't die...\n", cpu);
1711 		ret = -1;
1712 	}
1713 
1714 	return ret;
1715 }
1716 
1717 void native_cpu_die(unsigned int cpu)
1718 {
1719 	common_cpu_die(cpu);
1720 }
1721 
1722 void play_dead_common(void)
1723 {
1724 	idle_task_exit();
1725 
1726 	/* Ack it */
1727 	(void)cpu_report_death();
1728 
1729 	/*
1730 	 * With physical CPU hotplug, we should halt the cpu
1731 	 */
1732 	local_irq_disable();
1733 }
1734 
1735 /**
1736  * cond_wakeup_cpu0 - Wake up CPU0 if needed.
1737  *
1738  * If NMI wants to wake up CPU0, start CPU0.
1739  */
1740 void cond_wakeup_cpu0(void)
1741 {
1742 	if (smp_processor_id() == 0 && enable_start_cpu0)
1743 		start_cpu0();
1744 }
1745 EXPORT_SYMBOL_GPL(cond_wakeup_cpu0);
1746 
1747 /*
1748  * We need to flush the caches before going to sleep, lest we have
1749  * dirty data in our caches when we come back up.
1750  */
1751 static inline void mwait_play_dead(void)
1752 {
1753 	unsigned int eax, ebx, ecx, edx;
1754 	unsigned int highest_cstate = 0;
1755 	unsigned int highest_subcstate = 0;
1756 	void *mwait_ptr;
1757 	int i;
1758 
1759 	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
1760 	    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
1761 		return;
1762 	if (!this_cpu_has(X86_FEATURE_MWAIT))
1763 		return;
1764 	if (!this_cpu_has(X86_FEATURE_CLFLUSH))
1765 		return;
1766 	if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
1767 		return;
1768 
1769 	eax = CPUID_MWAIT_LEAF;
1770 	ecx = 0;
1771 	native_cpuid(&eax, &ebx, &ecx, &edx);
1772 
1773 	/*
1774 	 * eax will be 0 if EDX enumeration is not valid.
1775 	 * Initialized below to cstate, sub_cstate value when EDX is valid.
1776 	 */
1777 	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
1778 		eax = 0;
1779 	} else {
1780 		edx >>= MWAIT_SUBSTATE_SIZE;
1781 		for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
1782 			if (edx & MWAIT_SUBSTATE_MASK) {
1783 				highest_cstate = i;
1784 				highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
1785 			}
1786 		}
1787 		eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
1788 			(highest_subcstate - 1);
1789 	}
1790 
1791 	/*
1792 	 * This should be a memory location in a cache line which is
1793 	 * unlikely to be touched by other processors.  The actual
1794 	 * content is immaterial as it is not actually modified in any way.
1795 	 */
1796 	mwait_ptr = &current_thread_info()->flags;
1797 
1798 	wbinvd();
1799 
1800 	while (1) {
1801 		/*
1802 		 * The CLFLUSH is a workaround for erratum AAI65 for
1803 		 * the Xeon 7400 series.  It's not clear it is actually
1804 		 * needed, but it should be harmless in either case.
1805 		 * The WBINVD is insufficient due to the spurious-wakeup
1806 		 * case where we return around the loop.
1807 		 */
1808 		mb();
1809 		clflush(mwait_ptr);
1810 		mb();
1811 		__monitor(mwait_ptr, 0, 0);
1812 		mb();
1813 		__mwait(eax, 0);
1814 
1815 		cond_wakeup_cpu0();
1816 	}
1817 }
1818 
1819 void hlt_play_dead(void)
1820 {
1821 	if (__this_cpu_read(cpu_info.x86) >= 4)
1822 		wbinvd();
1823 
1824 	while (1) {
1825 		native_halt();
1826 
1827 		cond_wakeup_cpu0();
1828 	}
1829 }
1830 
1831 void native_play_dead(void)
1832 {
1833 	play_dead_common();
1834 	tboot_shutdown(TB_SHUTDOWN_WFS);
1835 
1836 	mwait_play_dead();	/* Only returns on failure */
1837 	if (cpuidle_play_dead())
1838 		hlt_play_dead();
1839 }
1840 
1841 #else /* ... !CONFIG_HOTPLUG_CPU */
1842 int native_cpu_disable(void)
1843 {
1844 	return -ENOSYS;
1845 }
1846 
1847 void native_cpu_die(unsigned int cpu)
1848 {
1849 	/* We said "no" in __cpu_disable */
1850 	BUG();
1851 }
1852 
1853 void native_play_dead(void)
1854 {
1855 	BUG();
1856 }
1857 
1858 #endif
1859