1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * x86 SMP booting functions
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.
9 * Much of the core SMP work is based on previous work by Thomas Radke, to
10 * whom a great many thanks are extended.
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.
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
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
40 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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/kexec.h>
57 #include <linux/numa.h>
58 #include <linux/pgtable.h>
59 #include <linux/overflow.h>
60 #include <linux/stackprotector.h>
61 #include <linux/cpuhotplug.h>
62 #include <linux/mc146818rtc.h>
65 #include <asm/cacheinfo.h>
69 #include <asm/realmode.h>
72 #include <asm/tlbflush.h>
74 #include <asm/mwait.h>
76 #include <asm/io_apic.h>
77 #include <asm/fpu/api.h>
78 #include <asm/setup.h>
79 #include <asm/uv/uv.h>
80 #include <asm/microcode.h>
81 #include <asm/i8259.h>
83 #include <asm/qspinlock.h>
84 #include <asm/intel-family.h>
85 #include <asm/cpu_device_id.h>
86 #include <asm/spec-ctrl.h>
87 #include <asm/hw_irq.h>
88 #include <asm/stackprotector.h>
91 /* representing HT siblings of each logical CPU */
92 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
93 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
95 /* representing HT and core siblings of each logical CPU */
96 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
97 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
99 /* representing HT, core, and die siblings of each logical CPU */
100 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_die_map);
101 EXPORT_PER_CPU_SYMBOL(cpu_die_map);
103 /* Per CPU bogomips and other parameters */
104 DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
105 EXPORT_PER_CPU_SYMBOL(cpu_info);
107 /* CPUs which are the primary SMT threads */
108 struct cpumask __cpu_primary_thread_mask __read_mostly;
110 /* Representing CPUs for which sibling maps can be computed */
111 static cpumask_var_t cpu_sibling_setup_mask;
113 struct mwait_cpu_dead {
114 unsigned int control;
118 #define CPUDEAD_MWAIT_WAIT 0xDEADBEEF
119 #define CPUDEAD_MWAIT_KEXEC_HLT 0x4A17DEAD
122 * Cache line aligned data for mwait_play_dead(). Separate on purpose so
123 * that it's unlikely to be touched by other CPUs.
125 static DEFINE_PER_CPU_ALIGNED(struct mwait_cpu_dead, mwait_cpu_dead);
127 /* Logical package management. We might want to allocate that dynamically */
128 unsigned int __max_logical_packages __read_mostly;
129 EXPORT_SYMBOL(__max_logical_packages);
130 static unsigned int logical_packages __read_mostly;
131 static unsigned int logical_die __read_mostly;
133 /* Maximum number of SMT threads on any online core */
134 int __read_mostly __max_smt_threads = 1;
136 /* Flag to indicate if a complete sched domain rebuild is required */
137 bool x86_topology_update;
139 int arch_update_cpu_topology(void)
141 int retval = x86_topology_update;
143 x86_topology_update = false;
147 static unsigned int smpboot_warm_reset_vector_count;
149 static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
153 spin_lock_irqsave(&rtc_lock, flags);
154 if (!smpboot_warm_reset_vector_count++) {
155 CMOS_WRITE(0xa, 0xf);
156 *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) = start_eip >> 4;
157 *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = start_eip & 0xf;
159 spin_unlock_irqrestore(&rtc_lock, flags);
162 static inline void smpboot_restore_warm_reset_vector(void)
167 * Paranoid: Set warm reset code and vector here back
170 spin_lock_irqsave(&rtc_lock, flags);
171 if (!--smpboot_warm_reset_vector_count) {
173 *((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0;
175 spin_unlock_irqrestore(&rtc_lock, flags);
179 /* Run the next set of setup steps for the upcoming CPU */
180 static void ap_starting(void)
182 int cpuid = smp_processor_id();
184 /* Mop up eventual mwait_play_dead() wreckage */
185 this_cpu_write(mwait_cpu_dead.status, 0);
186 this_cpu_write(mwait_cpu_dead.control, 0);
189 * If woken up by an INIT in an 82489DX configuration the alive
190 * synchronization guarantees that the CPU does not reach this
191 * point before an INIT_deassert IPI reaches the local APIC, so it
192 * is now safe to touch the local APIC.
194 * Set up this CPU, first the APIC, which is probably redundant on
199 /* Save the processor parameters. */
200 smp_store_cpu_info(cpuid);
203 * The topology information must be up to date before
204 * notify_cpu_starting().
206 set_cpu_sibling_map(cpuid);
208 ap_init_aperfmperf();
210 pr_debug("Stack at about %p\n", &cpuid);
215 * This runs the AP through all the cpuhp states to its target
216 * state CPUHP_ONLINE.
218 notify_cpu_starting(cpuid);
221 static void ap_calibrate_delay(void)
224 * Calibrate the delay loop and update loops_per_jiffy in cpu_data.
225 * smp_store_cpu_info() stored a value that is close but not as
226 * accurate as the value just calculated.
228 * As this is invoked after the TSC synchronization check,
229 * calibrate_delay_is_known() will skip the calibration routine
230 * when TSC is synchronized across sockets.
233 cpu_data(smp_processor_id()).loops_per_jiffy = loops_per_jiffy;
237 * Activate a secondary processor.
239 static void notrace start_secondary(void *unused)
242 * Don't put *anything* except direct CPU state initialization
243 * before cpu_init(), SMP booting is too fragile that we want to
244 * limit the things done here to the most necessary things.
249 * 32-bit specific. 64-bit reaches this code with the correct page
250 * table established. Yet another historical divergence.
252 if (IS_ENABLED(CONFIG_X86_32)) {
253 /* switch away from the initial page table */
254 load_cr3(swapper_pg_dir);
258 cpu_init_exception_handling();
261 * 32-bit systems load the microcode from the ASM startup code for
262 * historical reasons.
264 * On 64-bit systems load it before reaching the AP alive
265 * synchronization point below so it is not part of the full per
266 * CPU serialized bringup part when "parallel" bringup is enabled.
268 * That's even safe when hyperthreading is enabled in the CPU as
269 * the core code starts the primary threads first and leaves the
270 * secondary threads waiting for SIPI. Loading microcode on
271 * physical cores concurrently is a safe operation.
273 * This covers both the Intel specific issue that concurrent
274 * microcode loading on SMT siblings must be prohibited and the
275 * vendor independent issue`that microcode loading which changes
276 * CPUID, MSRs etc. must be strictly serialized to maintain
277 * software state correctness.
279 if (IS_ENABLED(CONFIG_X86_64))
283 * Synchronization point with the hotplug core. Sets this CPUs
284 * synchronization state to ALIVE and spin-waits for the control CPU to
285 * release this CPU for further bringup.
287 cpuhp_ap_sync_alive();
291 rcu_cpu_starting(raw_smp_processor_id());
292 x86_cpuinit.early_percpu_clock_init();
296 /* Check TSC synchronization with the control CPU. */
297 check_tsc_sync_target();
300 * Calibrate the delay loop after the TSC synchronization check.
301 * This allows to skip the calibration when TSC is synchronized
304 ap_calibrate_delay();
306 speculative_store_bypass_ht_init();
309 * Lock vector_lock, set CPU online and bring the vector
310 * allocator online. Online must be set with vector_lock held
311 * to prevent a concurrent irq setup/teardown from seeing a
312 * half valid vector space.
315 set_cpu_online(smp_processor_id(), true);
317 unlock_vector_lock();
318 x86_platform.nmi_init();
320 /* enable local interrupts */
323 x86_cpuinit.setup_percpu_clockev();
326 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
330 * topology_smt_supported - Check whether SMT is supported by the CPUs
332 bool topology_smt_supported(void)
334 return smp_num_siblings > 1;
338 * topology_phys_to_logical_pkg - Map a physical package id to a logical
339 * @phys_pkg: The physical package id to map
341 * Returns logical package id or -1 if not found
343 int topology_phys_to_logical_pkg(unsigned int phys_pkg)
347 for_each_possible_cpu(cpu) {
348 struct cpuinfo_x86 *c = &cpu_data(cpu);
350 if (c->initialized && c->phys_proc_id == phys_pkg)
351 return c->logical_proc_id;
355 EXPORT_SYMBOL(topology_phys_to_logical_pkg);
358 * topology_phys_to_logical_die - Map a physical die id to logical
359 * @die_id: The physical die id to map
360 * @cur_cpu: The CPU for which the mapping is done
362 * Returns logical die id or -1 if not found
364 static int topology_phys_to_logical_die(unsigned int die_id, unsigned int cur_cpu)
366 int cpu, proc_id = cpu_data(cur_cpu).phys_proc_id;
368 for_each_possible_cpu(cpu) {
369 struct cpuinfo_x86 *c = &cpu_data(cpu);
371 if (c->initialized && c->cpu_die_id == die_id &&
372 c->phys_proc_id == proc_id)
373 return c->logical_die_id;
379 * topology_update_package_map - Update the physical to logical package map
380 * @pkg: The physical package id as retrieved via CPUID
381 * @cpu: The cpu for which this is updated
383 int topology_update_package_map(unsigned int pkg, unsigned int cpu)
387 /* Already available somewhere? */
388 new = topology_phys_to_logical_pkg(pkg);
392 new = logical_packages++;
394 pr_info("CPU %u Converting physical %u to logical package %u\n",
398 cpu_data(cpu).logical_proc_id = new;
402 * topology_update_die_map - Update the physical to logical die map
403 * @die: The die id as retrieved via CPUID
404 * @cpu: The cpu for which this is updated
406 int topology_update_die_map(unsigned int die, unsigned int cpu)
410 /* Already available somewhere? */
411 new = topology_phys_to_logical_die(die, cpu);
417 pr_info("CPU %u Converting physical %u to logical die %u\n",
421 cpu_data(cpu).logical_die_id = new;
425 void __init smp_store_boot_cpu_info(void)
427 int id = 0; /* CPU 0 */
428 struct cpuinfo_x86 *c = &cpu_data(id);
432 topology_update_package_map(c->phys_proc_id, id);
433 topology_update_die_map(c->cpu_die_id, id);
434 c->initialized = true;
438 * The bootstrap kernel entry code has set these up. Save them for
441 void smp_store_cpu_info(int id)
443 struct cpuinfo_x86 *c = &cpu_data(id);
445 /* Copy boot_cpu_data only on the first bringup */
450 * During boot time, CPU0 has this setup already. Save the info when
453 identify_secondary_cpu(c);
454 c->initialized = true;
458 topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
460 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
462 return (cpu_to_node(cpu1) == cpu_to_node(cpu2));
466 topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name)
468 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
470 return !WARN_ONCE(!topology_same_node(c, o),
471 "sched: CPU #%d's %s-sibling CPU #%d is not on the same node! "
472 "[node: %d != %d]. Ignoring dependency.\n",
473 cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2));
476 #define link_mask(mfunc, c1, c2) \
478 cpumask_set_cpu((c1), mfunc(c2)); \
479 cpumask_set_cpu((c2), mfunc(c1)); \
482 static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
484 if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
485 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
487 if (c->phys_proc_id == o->phys_proc_id &&
488 c->cpu_die_id == o->cpu_die_id &&
489 per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
490 if (c->cpu_core_id == o->cpu_core_id)
491 return topology_sane(c, o, "smt");
493 if ((c->cu_id != 0xff) &&
494 (o->cu_id != 0xff) &&
495 (c->cu_id == o->cu_id))
496 return topology_sane(c, o, "smt");
499 } else if (c->phys_proc_id == o->phys_proc_id &&
500 c->cpu_die_id == o->cpu_die_id &&
501 c->cpu_core_id == o->cpu_core_id) {
502 return topology_sane(c, o, "smt");
508 static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
510 if (c->phys_proc_id == o->phys_proc_id &&
511 c->cpu_die_id == o->cpu_die_id)
516 static bool match_l2c(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
518 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
520 /* If the arch didn't set up l2c_id, fall back to SMT */
521 if (per_cpu(cpu_l2c_id, cpu1) == BAD_APICID)
522 return match_smt(c, o);
524 /* Do not match if L2 cache id does not match: */
525 if (per_cpu(cpu_l2c_id, cpu1) != per_cpu(cpu_l2c_id, cpu2))
528 return topology_sane(c, o, "l2c");
532 * Unlike the other levels, we do not enforce keeping a
533 * multicore group inside a NUMA node. If this happens, we will
534 * discard the MC level of the topology later.
536 static bool match_pkg(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
538 if (c->phys_proc_id == o->phys_proc_id)
544 * Define intel_cod_cpu[] for Intel COD (Cluster-on-Die) CPUs.
546 * Any Intel CPU that has multiple nodes per package and does not
547 * match intel_cod_cpu[] has the SNC (Sub-NUMA Cluster) topology.
549 * When in SNC mode, these CPUs enumerate an LLC that is shared
550 * by multiple NUMA nodes. The LLC is shared for off-package data
551 * access but private to the NUMA node (half of the package) for
552 * on-package access. CPUID (the source of the information about
553 * the LLC) can only enumerate the cache as shared or unshared,
554 * but not this particular configuration.
557 static const struct x86_cpu_id intel_cod_cpu[] = {
558 X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, 0), /* COD */
559 X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, 0), /* COD */
560 X86_MATCH_INTEL_FAM6_MODEL(ANY, 1), /* SNC */
564 static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
566 const struct x86_cpu_id *id = x86_match_cpu(intel_cod_cpu);
567 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
568 bool intel_snc = id && id->driver_data;
570 /* Do not match if we do not have a valid APICID for cpu: */
571 if (per_cpu(cpu_llc_id, cpu1) == BAD_APICID)
574 /* Do not match if LLC id does not match: */
575 if (per_cpu(cpu_llc_id, cpu1) != per_cpu(cpu_llc_id, cpu2))
579 * Allow the SNC topology without warning. Return of false
580 * means 'c' does not share the LLC of 'o'. This will be
581 * reflected to userspace.
583 if (match_pkg(c, o) && !topology_same_node(c, o) && intel_snc)
586 return topology_sane(c, o, "llc");
590 #if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_CLUSTER) || defined(CONFIG_SCHED_MC)
591 static inline int x86_sched_itmt_flags(void)
593 return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0;
596 #ifdef CONFIG_SCHED_MC
597 static int x86_core_flags(void)
599 return cpu_core_flags() | x86_sched_itmt_flags();
602 #ifdef CONFIG_SCHED_SMT
603 static int x86_smt_flags(void)
605 return cpu_smt_flags();
608 #ifdef CONFIG_SCHED_CLUSTER
609 static int x86_cluster_flags(void)
611 return cpu_cluster_flags() | x86_sched_itmt_flags();
617 * Set if a package/die has multiple NUMA nodes inside.
618 * AMD Magny-Cours, Intel Cluster-on-Die, and Intel
619 * Sub-NUMA Clustering have this.
621 static bool x86_has_numa_in_package;
623 static struct sched_domain_topology_level x86_topology[6];
625 static void __init build_sched_topology(void)
629 #ifdef CONFIG_SCHED_SMT
630 x86_topology[i++] = (struct sched_domain_topology_level){
631 cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT)
634 #ifdef CONFIG_SCHED_CLUSTER
636 * For now, skip the cluster domain on Hybrid.
638 if (!cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) {
639 x86_topology[i++] = (struct sched_domain_topology_level){
640 cpu_clustergroup_mask, x86_cluster_flags, SD_INIT_NAME(CLS)
644 #ifdef CONFIG_SCHED_MC
645 x86_topology[i++] = (struct sched_domain_topology_level){
646 cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC)
650 * When there is NUMA topology inside the package skip the DIE domain
651 * since the NUMA domains will auto-magically create the right spanning
652 * domains based on the SLIT.
654 if (!x86_has_numa_in_package) {
655 x86_topology[i++] = (struct sched_domain_topology_level){
656 cpu_cpu_mask, SD_INIT_NAME(DIE)
661 * There must be one trailing NULL entry left.
663 BUG_ON(i >= ARRAY_SIZE(x86_topology)-1);
665 set_sched_topology(x86_topology);
668 void set_cpu_sibling_map(int cpu)
670 bool has_smt = smp_num_siblings > 1;
671 bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
672 struct cpuinfo_x86 *c = &cpu_data(cpu);
673 struct cpuinfo_x86 *o;
676 cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
679 cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu));
680 cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
681 cpumask_set_cpu(cpu, cpu_l2c_shared_mask(cpu));
682 cpumask_set_cpu(cpu, topology_core_cpumask(cpu));
683 cpumask_set_cpu(cpu, topology_die_cpumask(cpu));
688 for_each_cpu(i, cpu_sibling_setup_mask) {
691 if (match_pkg(c, o) && !topology_same_node(c, o))
692 x86_has_numa_in_package = true;
694 if ((i == cpu) || (has_smt && match_smt(c, o)))
695 link_mask(topology_sibling_cpumask, cpu, i);
697 if ((i == cpu) || (has_mp && match_llc(c, o)))
698 link_mask(cpu_llc_shared_mask, cpu, i);
700 if ((i == cpu) || (has_mp && match_l2c(c, o)))
701 link_mask(cpu_l2c_shared_mask, cpu, i);
703 if ((i == cpu) || (has_mp && match_die(c, o)))
704 link_mask(topology_die_cpumask, cpu, i);
707 threads = cpumask_weight(topology_sibling_cpumask(cpu));
708 if (threads > __max_smt_threads)
709 __max_smt_threads = threads;
711 for_each_cpu(i, topology_sibling_cpumask(cpu))
712 cpu_data(i).smt_active = threads > 1;
715 * This needs a separate iteration over the cpus because we rely on all
716 * topology_sibling_cpumask links to be set-up.
718 for_each_cpu(i, cpu_sibling_setup_mask) {
721 if ((i == cpu) || (has_mp && match_pkg(c, o))) {
722 link_mask(topology_core_cpumask, cpu, i);
725 * Does this new cpu bringup a new core?
729 * for each core in package, increment
730 * the booted_cores for this new cpu
733 topology_sibling_cpumask(i)) == i)
736 * increment the core count for all
737 * the other cpus in this package
740 cpu_data(i).booted_cores++;
741 } else if (i != cpu && !c->booted_cores)
742 c->booted_cores = cpu_data(i).booted_cores;
747 /* maps the cpu to the sched domain representing multi-core */
748 const struct cpumask *cpu_coregroup_mask(int cpu)
750 return cpu_llc_shared_mask(cpu);
753 const struct cpumask *cpu_clustergroup_mask(int cpu)
755 return cpu_l2c_shared_mask(cpu);
758 static void impress_friends(void)
761 unsigned long bogosum = 0;
763 * Allow the user to impress friends.
765 pr_debug("Before bogomips\n");
766 for_each_online_cpu(cpu)
767 bogosum += cpu_data(cpu).loops_per_jiffy;
769 pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n",
772 (bogosum/(5000/HZ))%100);
774 pr_debug("Before bogocount - setting activated=1\n");
778 * The Multiprocessor Specification 1.4 (1997) example code suggests
779 * that there should be a 10ms delay between the BSP asserting INIT
780 * and de-asserting INIT, when starting a remote processor.
781 * But that slows boot and resume on modern processors, which include
782 * many cores and don't require that delay.
784 * Cmdline "init_cpu_udelay=" is available to over-ride this delay.
785 * Modern processor families are quirked to remove the delay entirely.
787 #define UDELAY_10MS_DEFAULT 10000
789 static unsigned int init_udelay = UINT_MAX;
791 static int __init cpu_init_udelay(char *str)
793 get_option(&str, &init_udelay);
797 early_param("cpu_init_udelay", cpu_init_udelay);
799 static void __init smp_quirk_init_udelay(void)
801 /* if cmdline changed it from default, leave it alone */
802 if (init_udelay != UINT_MAX)
805 /* if modern processor, use no delay */
806 if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
807 ((boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) && (boot_cpu_data.x86 >= 0x18)) ||
808 ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
812 /* else, use legacy delay */
813 init_udelay = UDELAY_10MS_DEFAULT;
817 * Wake up AP by INIT, INIT, STARTUP sequence.
819 static void send_init_sequence(int phys_apicid)
821 int maxlvt = lapic_get_maxlvt();
823 /* Be paranoid about clearing APIC errors. */
824 if (APIC_INTEGRATED(boot_cpu_apic_version)) {
825 /* Due to the Pentium erratum 3AP. */
827 apic_write(APIC_ESR, 0);
831 /* Assert INIT on the target CPU */
832 apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT, phys_apicid);
833 safe_apic_wait_icr_idle();
837 /* Deassert INIT on the target CPU */
838 apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
839 safe_apic_wait_icr_idle();
843 * Wake up AP by INIT, INIT, STARTUP sequence.
845 static int wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
847 unsigned long send_status = 0, accept_status = 0;
848 int num_starts, j, maxlvt;
851 maxlvt = lapic_get_maxlvt();
852 send_init_sequence(phys_apicid);
857 * Should we send STARTUP IPIs ?
859 * Determine this based on the APIC version.
860 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
862 if (APIC_INTEGRATED(boot_cpu_apic_version))
868 * Run STARTUP IPI loop.
870 pr_debug("#startup loops: %d\n", num_starts);
872 for (j = 1; j <= num_starts; j++) {
873 pr_debug("Sending STARTUP #%d\n", j);
874 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
875 apic_write(APIC_ESR, 0);
877 pr_debug("After apic_write\n");
884 /* Boot on the stack */
885 /* Kick the second */
886 apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
890 * Give the other CPU some time to accept the IPI.
892 if (init_udelay == 0)
897 pr_debug("Startup point 1\n");
899 pr_debug("Waiting for send to finish...\n");
900 send_status = safe_apic_wait_icr_idle();
903 * Give the other CPU some time to accept the IPI.
905 if (init_udelay == 0)
910 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
911 apic_write(APIC_ESR, 0);
912 accept_status = (apic_read(APIC_ESR) & 0xEF);
913 if (send_status || accept_status)
916 pr_debug("After Startup\n");
919 pr_err("APIC never delivered???\n");
921 pr_err("APIC delivery error (%lx)\n", accept_status);
924 return (send_status | accept_status);
927 /* reduce the number of lines printed when booting a large cpu count system */
928 static void announce_cpu(int cpu, int apicid)
930 static int width, node_width, first = 1;
931 static int current_node = NUMA_NO_NODE;
932 int node = early_cpu_to_node(cpu);
935 width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */
938 node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */
940 if (system_state < SYSTEM_RUNNING) {
942 pr_info("x86: Booting SMP configuration:\n");
944 if (node != current_node) {
945 if (current_node > (-1))
949 printk(KERN_INFO ".... node %*s#%d, CPUs: ",
950 node_width - num_digits(node), " ", node);
953 /* Add padding for the BSP */
955 pr_cont("%*s", width + 1, " ");
958 pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);
960 pr_info("Booting Node %d Processor %d APIC 0x%x\n",
964 int common_cpu_up(unsigned int cpu, struct task_struct *idle)
968 /* Just in case we booted with a single CPU. */
969 alternatives_enable_smp();
971 per_cpu(pcpu_hot.current_task, cpu) = idle;
972 cpu_init_stack_canary(cpu, idle);
974 /* Initialize the interrupt stack(s) */
975 ret = irq_init_percpu_irqstack(cpu);
980 /* Stack for startup_32 can be just as for start_secondary onwards */
981 per_cpu(pcpu_hot.top_of_stack, cpu) = task_top_of_stack(idle);
987 * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
988 * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
989 * Returns zero if startup was successfully sent, else error code from
990 * ->wakeup_secondary_cpu.
992 static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle)
994 unsigned long start_ip = real_mode_header->trampoline_start;
998 /* If 64-bit wakeup method exists, use the 64-bit mode trampoline IP */
999 if (apic->wakeup_secondary_cpu_64)
1000 start_ip = real_mode_header->trampoline_start64;
1002 idle->thread.sp = (unsigned long)task_pt_regs(idle);
1003 initial_code = (unsigned long)start_secondary;
1005 if (IS_ENABLED(CONFIG_X86_32)) {
1006 early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu);
1007 initial_stack = idle->thread.sp;
1008 } else if (!(smpboot_control & STARTUP_PARALLEL_MASK)) {
1009 smpboot_control = cpu;
1012 /* Enable the espfix hack for this CPU */
1013 init_espfix_ap(cpu);
1015 /* So we see what's up */
1016 announce_cpu(cpu, apicid);
1019 * This grunge runs the startup process for
1020 * the targeted processor.
1022 if (x86_platform.legacy.warm_reset) {
1024 pr_debug("Setting warm reset code and vector.\n");
1026 smpboot_setup_warm_reset_vector(start_ip);
1028 * Be paranoid about clearing APIC errors.
1030 if (APIC_INTEGRATED(boot_cpu_apic_version)) {
1031 apic_write(APIC_ESR, 0);
1032 apic_read(APIC_ESR);
1039 * Wake up a CPU in difference cases:
1040 * - Use a method from the APIC driver if one defined, with wakeup
1041 * straight to 64-bit mode preferred over wakeup to RM.
1043 * - Use an INIT boot APIC message
1045 if (apic->wakeup_secondary_cpu_64)
1046 ret = apic->wakeup_secondary_cpu_64(apicid, start_ip);
1047 else if (apic->wakeup_secondary_cpu)
1048 ret = apic->wakeup_secondary_cpu(apicid, start_ip);
1050 ret = wakeup_secondary_cpu_via_init(apicid, start_ip);
1052 /* If the wakeup mechanism failed, cleanup the warm reset vector */
1054 arch_cpuhp_cleanup_kick_cpu(cpu);
1058 int native_kick_ap(unsigned int cpu, struct task_struct *tidle)
1060 int apicid = apic->cpu_present_to_apicid(cpu);
1063 lockdep_assert_irqs_enabled();
1065 pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu);
1067 if (apicid == BAD_APICID ||
1068 !physid_isset(apicid, phys_cpu_present_map) ||
1069 !apic->apic_id_valid(apicid)) {
1070 pr_err("%s: bad cpu %d\n", __func__, cpu);
1075 * Save current MTRR state in case it was changed since early boot
1076 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
1080 /* the FPU context is blank, nobody can own it */
1081 per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL;
1083 err = common_cpu_up(cpu, tidle);
1087 err = do_boot_cpu(apicid, cpu, tidle);
1089 pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
1094 int arch_cpuhp_kick_ap_alive(unsigned int cpu, struct task_struct *tidle)
1096 return smp_ops.kick_ap_alive(cpu, tidle);
1099 void arch_cpuhp_cleanup_kick_cpu(unsigned int cpu)
1101 /* Cleanup possible dangling ends... */
1102 if (smp_ops.kick_ap_alive == native_kick_ap && x86_platform.legacy.warm_reset)
1103 smpboot_restore_warm_reset_vector();
1106 void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu)
1108 if (smp_ops.cleanup_dead_cpu)
1109 smp_ops.cleanup_dead_cpu(cpu);
1111 if (system_state == SYSTEM_RUNNING)
1112 pr_info("CPU %u is now offline\n", cpu);
1115 void arch_cpuhp_sync_state_poll(void)
1117 if (smp_ops.poll_sync_state)
1118 smp_ops.poll_sync_state();
1122 * arch_disable_smp_support() - Disables SMP support for x86 at boottime
1124 void __init arch_disable_smp_support(void)
1126 disable_ioapic_support();
1130 * Fall back to non SMP mode after errors.
1132 * RED-PEN audit/test this more. I bet there is more state messed up here.
1134 static __init void disable_smp(void)
1136 pr_info("SMP disabled\n");
1138 disable_ioapic_support();
1140 init_cpu_present(cpumask_of(0));
1141 init_cpu_possible(cpumask_of(0));
1143 if (smp_found_config)
1144 physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
1146 physid_set_mask_of_physid(0, &phys_cpu_present_map);
1147 cpumask_set_cpu(0, topology_sibling_cpumask(0));
1148 cpumask_set_cpu(0, topology_core_cpumask(0));
1149 cpumask_set_cpu(0, topology_die_cpumask(0));
1153 * Various sanity checks.
1155 static void __init smp_sanity_check(void)
1159 #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
1160 if (def_to_bigsmp && nr_cpu_ids > 8) {
1164 pr_warn("More than 8 CPUs detected - skipping them\n"
1165 "Use CONFIG_X86_BIGSMP\n");
1168 for_each_present_cpu(cpu) {
1170 set_cpu_present(cpu, false);
1175 for_each_possible_cpu(cpu) {
1177 set_cpu_possible(cpu, false);
1185 if (!physid_isset(read_apic_id(), phys_cpu_present_map)) {
1186 pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n",
1189 physid_set(read_apic_id(), phys_cpu_present_map);
1193 * Should not be necessary because the MP table should list the boot
1194 * CPU too, but we do it for the sake of robustness anyway.
1196 if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
1197 pr_notice("weird, boot CPU (#%d) not listed by the BIOS\n",
1198 boot_cpu_physical_apicid);
1199 physid_set(read_apic_id(), phys_cpu_present_map);
1204 static void __init smp_cpu_index_default(void)
1207 struct cpuinfo_x86 *c;
1209 for_each_possible_cpu(i) {
1211 /* mark all to hotplug */
1212 c->cpu_index = nr_cpu_ids;
1216 void __init smp_prepare_cpus_common(void)
1220 smp_cpu_index_default();
1223 * Setup boot CPU information
1225 smp_store_boot_cpu_info(); /* Final full version of the data */
1228 for_each_possible_cpu(i) {
1229 zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
1230 zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
1231 zalloc_cpumask_var(&per_cpu(cpu_die_map, i), GFP_KERNEL);
1232 zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
1233 zalloc_cpumask_var(&per_cpu(cpu_l2c_shared_map, i), GFP_KERNEL);
1236 set_cpu_sibling_map(0);
1239 #ifdef CONFIG_X86_64
1240 /* Establish whether parallel bringup can be supported. */
1241 bool __init arch_cpuhp_init_parallel_bringup(void)
1243 if (!x86_cpuinit.parallel_bringup) {
1244 pr_info("Parallel CPU startup disabled by the platform\n");
1248 smpboot_control = STARTUP_READ_APICID;
1249 pr_debug("Parallel CPU startup enabled: 0x%08x\n", smpboot_control);
1255 * Prepare for SMP bootup.
1256 * @max_cpus: configured maximum number of CPUs, It is a legacy parameter
1257 * for common interface support.
1259 void __init native_smp_prepare_cpus(unsigned int max_cpus)
1261 smp_prepare_cpus_common();
1265 switch (apic_intr_mode) {
1267 case APIC_VIRTUAL_WIRE_NO_CONFIG:
1270 case APIC_SYMMETRIC_IO_NO_ROUTING:
1272 /* Setup local timer */
1273 x86_init.timers.setup_percpu_clockev();
1275 case APIC_VIRTUAL_WIRE:
1276 case APIC_SYMMETRIC_IO:
1280 /* Setup local timer */
1281 x86_init.timers.setup_percpu_clockev();
1284 print_cpu_info(&cpu_data(0));
1288 smp_quirk_init_udelay();
1290 speculative_store_bypass_ht_init();
1292 snp_set_wakeup_secondary_cpu();
1295 void arch_thaw_secondary_cpus_begin(void)
1297 set_cache_aps_delayed_init(true);
1300 void arch_thaw_secondary_cpus_end(void)
1305 bool smp_park_other_cpus_in_init(void)
1307 unsigned int cpu, this_cpu = smp_processor_id();
1308 unsigned int apicid;
1310 if (apic->wakeup_secondary_cpu_64 || apic->wakeup_secondary_cpu)
1314 * If this is a crash stop which does not execute on the boot CPU,
1315 * then this cannot use the INIT mechanism because INIT to the boot
1316 * CPU will reset the machine.
1321 for_each_present_cpu(cpu) {
1322 if (cpu == this_cpu)
1324 apicid = apic->cpu_present_to_apicid(cpu);
1325 if (apicid == BAD_APICID)
1327 send_init_sequence(apicid);
1333 * Early setup to make printk work.
1335 void __init native_smp_prepare_boot_cpu(void)
1337 int me = smp_processor_id();
1339 /* SMP handles this from setup_per_cpu_areas() */
1340 if (!IS_ENABLED(CONFIG_SMP))
1341 switch_gdt_and_percpu_base(me);
1343 native_pv_lock_init();
1346 void __init calculate_max_logical_packages(void)
1351 * Today neither Intel nor AMD support heterogeneous systems so
1352 * extrapolate the boot cpu's data to all packages.
1354 ncpus = cpu_data(0).booted_cores * topology_max_smt_threads();
1355 __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
1356 pr_info("Max logical packages: %u\n", __max_logical_packages);
1359 void __init native_smp_cpus_done(unsigned int max_cpus)
1361 pr_debug("Boot done\n");
1363 calculate_max_logical_packages();
1364 build_sched_topology();
1370 static int __initdata setup_possible_cpus = -1;
1371 static int __init _setup_possible_cpus(char *str)
1373 get_option(&str, &setup_possible_cpus);
1376 early_param("possible_cpus", _setup_possible_cpus);
1380 * cpu_possible_mask should be static, it cannot change as cpu's
1381 * are onlined, or offlined. The reason is per-cpu data-structures
1382 * are allocated by some modules at init time, and don't expect to
1383 * do this dynamically on cpu arrival/departure.
1384 * cpu_present_mask on the other hand can change dynamically.
1385 * In case when cpu_hotplug is not compiled, then we resort to current
1386 * behaviour, which is cpu_possible == cpu_present.
1389 * Three ways to find out the number of additional hotplug CPUs:
1390 * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
1391 * - The user can overwrite it with possible_cpus=NUM
1392 * - Otherwise don't reserve additional CPUs.
1393 * We do this because additional CPUs waste a lot of memory.
1396 __init void prefill_possible_map(void)
1400 /* No boot processor was found in mptable or ACPI MADT */
1401 if (!num_processors) {
1402 if (boot_cpu_has(X86_FEATURE_APIC)) {
1403 int apicid = boot_cpu_physical_apicid;
1404 int cpu = read_apic_id();
1406 pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
1408 /* Make sure boot cpu is enumerated */
1409 if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
1410 apic->apic_id_valid(apicid))
1411 generic_processor_info(apicid, boot_cpu_apic_version);
1414 if (!num_processors)
1418 i = setup_max_cpus ?: 1;
1419 if (setup_possible_cpus == -1) {
1420 possible = num_processors;
1421 #ifdef CONFIG_HOTPLUG_CPU
1423 possible += disabled_cpus;
1429 possible = setup_possible_cpus;
1431 total_cpus = max_t(int, possible, num_processors + disabled_cpus);
1433 /* nr_cpu_ids could be reduced via nr_cpus= */
1434 if (possible > nr_cpu_ids) {
1435 pr_warn("%d Processors exceeds NR_CPUS limit of %u\n",
1436 possible, nr_cpu_ids);
1437 possible = nr_cpu_ids;
1440 #ifdef CONFIG_HOTPLUG_CPU
1441 if (!setup_max_cpus)
1444 pr_warn("%d Processors exceeds max_cpus limit of %u\n",
1445 possible, setup_max_cpus);
1449 set_nr_cpu_ids(possible);
1451 pr_info("Allowing %d CPUs, %d hotplug CPUs\n",
1452 possible, max_t(int, possible - num_processors, 0));
1454 reset_cpu_possible_mask();
1456 for (i = 0; i < possible; i++)
1457 set_cpu_possible(i, true);
1460 /* correctly size the local cpu masks */
1461 void __init setup_cpu_local_masks(void)
1463 alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask);
1466 #ifdef CONFIG_HOTPLUG_CPU
1468 /* Recompute SMT state for all CPUs on offline */
1469 static void recompute_smt_state(void)
1471 int max_threads, cpu;
1474 for_each_online_cpu (cpu) {
1475 int threads = cpumask_weight(topology_sibling_cpumask(cpu));
1477 if (threads > max_threads)
1478 max_threads = threads;
1480 __max_smt_threads = max_threads;
1483 static void remove_siblinginfo(int cpu)
1486 struct cpuinfo_x86 *c = &cpu_data(cpu);
1488 for_each_cpu(sibling, topology_core_cpumask(cpu)) {
1489 cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
1491 * last thread sibling in this cpu core going down
1493 if (cpumask_weight(topology_sibling_cpumask(cpu)) == 1)
1494 cpu_data(sibling).booted_cores--;
1497 for_each_cpu(sibling, topology_die_cpumask(cpu))
1498 cpumask_clear_cpu(cpu, topology_die_cpumask(sibling));
1500 for_each_cpu(sibling, topology_sibling_cpumask(cpu)) {
1501 cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
1502 if (cpumask_weight(topology_sibling_cpumask(sibling)) == 1)
1503 cpu_data(sibling).smt_active = false;
1506 for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
1507 cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
1508 for_each_cpu(sibling, cpu_l2c_shared_mask(cpu))
1509 cpumask_clear_cpu(cpu, cpu_l2c_shared_mask(sibling));
1510 cpumask_clear(cpu_llc_shared_mask(cpu));
1511 cpumask_clear(cpu_l2c_shared_mask(cpu));
1512 cpumask_clear(topology_sibling_cpumask(cpu));
1513 cpumask_clear(topology_core_cpumask(cpu));
1514 cpumask_clear(topology_die_cpumask(cpu));
1516 c->booted_cores = 0;
1517 cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
1518 recompute_smt_state();
1521 static void remove_cpu_from_maps(int cpu)
1523 set_cpu_online(cpu, false);
1524 numa_remove_cpu(cpu);
1527 void cpu_disable_common(void)
1529 int cpu = smp_processor_id();
1531 remove_siblinginfo(cpu);
1533 /* It's now safe to remove this processor from the online map */
1535 remove_cpu_from_maps(cpu);
1536 unlock_vector_lock();
1541 int native_cpu_disable(void)
1545 ret = lapic_can_unplug_cpu();
1549 cpu_disable_common();
1552 * Disable the local APIC. Otherwise IPI broadcasts will reach
1553 * it. It still responds normally to INIT, NMI, SMI, and SIPI
1556 * Disabling the APIC must happen after cpu_disable_common()
1557 * which invokes fixup_irqs().
1559 * Disabling the APIC preserves already set bits in IRR, but
1560 * an interrupt arriving after disabling the local APIC does not
1561 * set the corresponding IRR bit.
1563 * fixup_irqs() scans IRR for set bits so it can raise a not
1564 * yet handled interrupt on the new destination CPU via an IPI
1565 * but obviously it can't do so for IRR bits which are not set.
1566 * IOW, interrupts arriving after disabling the local APIC will
1569 apic_soft_disable();
1574 void play_dead_common(void)
1578 cpuhp_ap_report_dead();
1580 * With physical CPU hotplug, we should halt the cpu
1582 local_irq_disable();
1586 * We need to flush the caches before going to sleep, lest we have
1587 * dirty data in our caches when we come back up.
1589 static inline void mwait_play_dead(void)
1591 struct mwait_cpu_dead *md = this_cpu_ptr(&mwait_cpu_dead);
1592 unsigned int eax, ebx, ecx, edx;
1593 unsigned int highest_cstate = 0;
1594 unsigned int highest_subcstate = 0;
1597 if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
1598 boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
1600 if (!this_cpu_has(X86_FEATURE_MWAIT))
1602 if (!this_cpu_has(X86_FEATURE_CLFLUSH))
1604 if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
1607 eax = CPUID_MWAIT_LEAF;
1609 native_cpuid(&eax, &ebx, &ecx, &edx);
1612 * eax will be 0 if EDX enumeration is not valid.
1613 * Initialized below to cstate, sub_cstate value when EDX is valid.
1615 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
1618 edx >>= MWAIT_SUBSTATE_SIZE;
1619 for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
1620 if (edx & MWAIT_SUBSTATE_MASK) {
1622 highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
1625 eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
1626 (highest_subcstate - 1);
1629 /* Set up state for the kexec() hack below */
1630 md->status = CPUDEAD_MWAIT_WAIT;
1631 md->control = CPUDEAD_MWAIT_WAIT;
1637 * The CLFLUSH is a workaround for erratum AAI65 for
1638 * the Xeon 7400 series. It's not clear it is actually
1639 * needed, but it should be harmless in either case.
1640 * The WBINVD is insufficient due to the spurious-wakeup
1641 * case where we return around the loop.
1646 __monitor(md, 0, 0);
1650 if (READ_ONCE(md->control) == CPUDEAD_MWAIT_KEXEC_HLT) {
1652 * Kexec is about to happen. Don't go back into mwait() as
1653 * the kexec kernel might overwrite text and data including
1654 * page tables and stack. So mwait() would resume when the
1655 * monitor cache line is written to and then the CPU goes
1656 * south due to overwritten text, page tables and stack.
1658 * Note: This does _NOT_ protect against a stray MCE, NMI,
1659 * SMI. They will resume execution at the instruction
1660 * following the HLT instruction and run into the problem
1661 * which this is trying to prevent.
1663 WRITE_ONCE(md->status, CPUDEAD_MWAIT_KEXEC_HLT);
1671 * Kick all "offline" CPUs out of mwait on kexec(). See comment in
1672 * mwait_play_dead().
1674 void smp_kick_mwait_play_dead(void)
1676 u32 newstate = CPUDEAD_MWAIT_KEXEC_HLT;
1677 struct mwait_cpu_dead *md;
1678 unsigned int cpu, i;
1680 for_each_cpu_andnot(cpu, cpu_present_mask, cpu_online_mask) {
1681 md = per_cpu_ptr(&mwait_cpu_dead, cpu);
1683 /* Does it sit in mwait_play_dead() ? */
1684 if (READ_ONCE(md->status) != CPUDEAD_MWAIT_WAIT)
1687 /* Wait up to 5ms */
1688 for (i = 0; READ_ONCE(md->status) != newstate && i < 1000; i++) {
1689 /* Bring it out of mwait */
1690 WRITE_ONCE(md->control, newstate);
1694 if (READ_ONCE(md->status) != newstate)
1695 pr_err_once("CPU%u is stuck in mwait_play_dead()\n", cpu);
1699 void __noreturn hlt_play_dead(void)
1701 if (__this_cpu_read(cpu_info.x86) >= 4)
1708 void native_play_dead(void)
1711 tboot_shutdown(TB_SHUTDOWN_WFS);
1714 if (cpuidle_play_dead())
1718 #else /* ... !CONFIG_HOTPLUG_CPU */
1719 int native_cpu_disable(void)
1724 void native_play_dead(void)