2 * SMP initialisation and IPI support
3 * Based on arch/arm/kernel/smp.c
5 * Copyright (C) 2012 ARM Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #include <linux/acpi.h>
21 #include <linux/delay.h>
22 #include <linux/init.h>
23 #include <linux/spinlock.h>
24 #include <linux/sched/mm.h>
25 #include <linux/sched/hotplug.h>
26 #include <linux/sched/task_stack.h>
27 #include <linux/interrupt.h>
28 #include <linux/cache.h>
29 #include <linux/profile.h>
30 #include <linux/errno.h>
32 #include <linux/err.h>
33 #include <linux/cpu.h>
34 #include <linux/smp.h>
35 #include <linux/seq_file.h>
36 #include <linux/irq.h>
37 #include <linux/percpu.h>
38 #include <linux/clockchips.h>
39 #include <linux/completion.h>
41 #include <linux/irq_work.h>
42 #include <linux/kexec.h>
44 #include <asm/alternative.h>
45 #include <asm/atomic.h>
46 #include <asm/cacheflush.h>
48 #include <asm/cputype.h>
49 #include <asm/cpu_ops.h>
50 #include <asm/mmu_context.h>
52 #include <asm/pgtable.h>
53 #include <asm/pgalloc.h>
54 #include <asm/processor.h>
55 #include <asm/smp_plat.h>
56 #include <asm/sections.h>
57 #include <asm/tlbflush.h>
58 #include <asm/ptrace.h>
61 #define CREATE_TRACE_POINTS
62 #include <trace/events/ipi.h>
64 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
65 EXPORT_PER_CPU_SYMBOL(cpu_number);
68 * as from 2.5, kernels no longer have an init_tasks structure
69 * so we need some other way of telling a new secondary core
70 * where to place its SVC stack
72 struct secondary_data secondary_data;
73 /* Number of CPUs which aren't online, but looping in kernel text. */
74 int cpus_stuck_in_kernel;
86 #ifdef CONFIG_HOTPLUG_CPU
87 static int op_cpu_kill(unsigned int cpu);
89 static inline int op_cpu_kill(unsigned int cpu)
97 * Boot a secondary CPU, and assign it the specified idle task.
98 * This also gives us the initial stack to use for this CPU.
100 static int boot_secondary(unsigned int cpu, struct task_struct *idle)
102 if (cpu_ops[cpu]->cpu_boot)
103 return cpu_ops[cpu]->cpu_boot(cpu);
108 static DECLARE_COMPLETION(cpu_running);
109 bool va52mismatch __ro_after_init;
111 int __cpu_up(unsigned int cpu, struct task_struct *idle)
117 * We need to tell the secondary core where to find its stack and the
120 secondary_data.task = idle;
121 secondary_data.stack = task_stack_page(idle) + THREAD_SIZE;
122 update_cpu_boot_status(CPU_MMU_OFF);
123 __flush_dcache_area(&secondary_data, sizeof(secondary_data));
126 * Now bring the CPU into our world.
128 ret = boot_secondary(cpu, idle);
131 * CPU was successfully started, wait for it to come online or
134 wait_for_completion_timeout(&cpu_running,
135 msecs_to_jiffies(1000));
137 if (!cpu_online(cpu)) {
138 pr_crit("CPU%u: failed to come online\n", cpu);
140 if (IS_ENABLED(CONFIG_ARM64_52BIT_VA) && va52mismatch)
141 pr_crit("CPU%u: does not support 52-bit VAs\n", cpu);
146 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
150 secondary_data.task = NULL;
151 secondary_data.stack = NULL;
152 status = READ_ONCE(secondary_data.status);
155 if (status == CPU_MMU_OFF)
156 status = READ_ONCE(__early_cpu_boot_status);
160 pr_err("CPU%u: failed in unknown state : 0x%lx\n",
164 if (!op_cpu_kill(cpu)) {
165 pr_crit("CPU%u: died during early boot\n", cpu);
169 pr_crit("CPU%u: may not have shut down cleanly\n", cpu);
170 case CPU_STUCK_IN_KERNEL:
171 pr_crit("CPU%u: is stuck in kernel\n", cpu);
172 cpus_stuck_in_kernel++;
174 case CPU_PANIC_KERNEL:
175 panic("CPU%u detected unsupported configuration\n", cpu);
183 * This is the secondary CPU boot entry. We're using this CPUs
184 * idle thread stack, but a set of temporary page tables.
186 asmlinkage notrace void secondary_start_kernel(void)
188 struct mm_struct *mm = &init_mm;
191 cpu = task_cpu(current);
192 set_my_cpu_offset(per_cpu_offset(cpu));
195 * All kernel threads share the same mm context; grab a
196 * reference and switch to it.
199 current->active_mm = mm;
202 * TTBR0 is only used for the identity mapping at this stage. Make it
203 * point to zero page to avoid speculatively fetching new entries.
205 cpu_uninstall_idmap();
208 trace_hardirqs_off();
211 * If the system has established the capabilities, make sure
212 * this CPU ticks all of those. If it doesn't, the CPU will
213 * fail to come online.
215 check_local_cpu_capabilities();
217 if (cpu_ops[cpu]->cpu_postboot)
218 cpu_ops[cpu]->cpu_postboot();
221 * Log the CPU info before it is marked online and might get read.
226 * Enable GIC and timers.
228 notify_cpu_starting(cpu);
230 store_cpu_topology(cpu);
233 * OK, now it's safe to let the boot CPU continue. Wait for
234 * the CPU migration code to notice that the CPU is online
235 * before we continue.
237 pr_info("CPU%u: Booted secondary processor [%08x]\n",
238 cpu, read_cpuid_id());
239 update_cpu_boot_status(CPU_BOOT_SUCCESS);
240 set_cpu_online(cpu, true);
241 complete(&cpu_running);
244 local_async_enable();
247 * OK, it's off to the idle thread for us
249 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
252 #ifdef CONFIG_HOTPLUG_CPU
253 static int op_cpu_disable(unsigned int cpu)
256 * If we don't have a cpu_die method, abort before we reach the point
257 * of no return. CPU0 may not have an cpu_ops, so test for it.
259 if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_die)
263 * We may need to abort a hot unplug for some other mechanism-specific
266 if (cpu_ops[cpu]->cpu_disable)
267 return cpu_ops[cpu]->cpu_disable(cpu);
273 * __cpu_disable runs on the processor to be shutdown.
275 int __cpu_disable(void)
277 unsigned int cpu = smp_processor_id();
280 ret = op_cpu_disable(cpu);
285 * Take this CPU offline. Once we clear this, we can't return,
286 * and we must not schedule until we're ready to give up the cpu.
288 set_cpu_online(cpu, false);
291 * OK - migrate IRQs away from this CPU
293 irq_migrate_all_off_this_cpu();
298 static int op_cpu_kill(unsigned int cpu)
301 * If we have no means of synchronising with the dying CPU, then assume
302 * that it is really dead. We can only wait for an arbitrary length of
303 * time and hope that it's dead, so let's skip the wait and just hope.
305 if (!cpu_ops[cpu]->cpu_kill)
308 return cpu_ops[cpu]->cpu_kill(cpu);
312 * called on the thread which is asking for a CPU to be shutdown -
313 * waits until shutdown has completed, or it is timed out.
315 void __cpu_die(unsigned int cpu)
319 if (!cpu_wait_death(cpu, 5)) {
320 pr_crit("CPU%u: cpu didn't die\n", cpu);
323 pr_notice("CPU%u: shutdown\n", cpu);
326 * Now that the dying CPU is beyond the point of no return w.r.t.
327 * in-kernel synchronisation, try to get the firwmare to help us to
328 * verify that it has really left the kernel before we consider
329 * clobbering anything it might still be using.
331 err = op_cpu_kill(cpu);
333 pr_warn("CPU%d may not have shut down cleanly: %d\n",
338 * Called from the idle thread for the CPU which has been shutdown.
340 * Note that we disable IRQs here, but do not re-enable them
341 * before returning to the caller. This is also the behaviour
342 * of the other hotplug-cpu capable cores, so presumably coming
343 * out of idle fixes this.
347 unsigned int cpu = smp_processor_id();
353 /* Tell __cpu_die() that this CPU is now safe to dispose of */
354 (void)cpu_report_death();
357 * Actually shutdown the CPU. This must never fail. The specific hotplug
358 * mechanism must perform all required cache maintenance to ensure that
359 * no dirty lines are lost in the process of shutting down the CPU.
361 cpu_ops[cpu]->cpu_die(cpu);
368 * Kill the calling secondary CPU, early in bringup before it is turned
371 void cpu_die_early(void)
373 int cpu = smp_processor_id();
375 pr_crit("CPU%d: will not boot\n", cpu);
377 /* Mark this CPU absent */
378 set_cpu_present(cpu, 0);
380 #ifdef CONFIG_HOTPLUG_CPU
381 update_cpu_boot_status(CPU_KILL_ME);
382 /* Check if we can park ourselves */
383 if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_die)
384 cpu_ops[cpu]->cpu_die(cpu);
386 update_cpu_boot_status(CPU_STUCK_IN_KERNEL);
391 static void __init hyp_mode_check(void)
393 if (is_hyp_mode_available())
394 pr_info("CPU: All CPU(s) started at EL2\n");
395 else if (is_hyp_mode_mismatched())
396 WARN_TAINT(1, TAINT_CPU_OUT_OF_SPEC,
397 "CPU: CPUs started in inconsistent modes");
399 pr_info("CPU: All CPU(s) started at EL1\n");
402 void __init smp_cpus_done(unsigned int max_cpus)
404 pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
405 setup_cpu_features();
407 apply_alternatives_all();
408 mark_linear_text_alias_ro();
411 void __init smp_prepare_boot_cpu(void)
413 set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
415 * Initialise the static keys early as they may be enabled by the
419 cpuinfo_store_boot_cpu();
422 static u64 __init of_get_cpu_mpidr(struct device_node *dn)
428 * A cpu node with missing "reg" property is
429 * considered invalid to build a cpu_logical_map
432 cell = of_get_property(dn, "reg", NULL);
434 pr_err("%pOF: missing reg property\n", dn);
438 hwid = of_read_number(cell, of_n_addr_cells(dn));
440 * Non affinity bits must be set to 0 in the DT
442 if (hwid & ~MPIDR_HWID_BITMASK) {
443 pr_err("%pOF: invalid reg property\n", dn);
450 * Duplicate MPIDRs are a recipe for disaster. Scan all initialized
451 * entries and check for duplicates. If any is found just ignore the
452 * cpu. cpu_logical_map was initialized to INVALID_HWID to avoid
453 * matching valid MPIDR values.
455 static bool __init is_mpidr_duplicate(unsigned int cpu, u64 hwid)
459 for (i = 1; (i < cpu) && (i < NR_CPUS); i++)
460 if (cpu_logical_map(i) == hwid)
466 * Initialize cpu operations for a logical cpu and
467 * set it in the possible mask on success
469 static int __init smp_cpu_setup(int cpu)
471 if (cpu_read_ops(cpu))
474 if (cpu_ops[cpu]->cpu_init(cpu))
477 set_cpu_possible(cpu, true);
482 static bool bootcpu_valid __initdata;
483 static unsigned int cpu_count = 1;
486 static struct acpi_madt_generic_interrupt cpu_madt_gicc[NR_CPUS];
488 struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu)
490 return &cpu_madt_gicc[cpu];
494 * acpi_map_gic_cpu_interface - parse processor MADT entry
496 * Carry out sanity checks on MADT processor entry and initialize
497 * cpu_logical_map on success
500 acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
502 u64 hwid = processor->arm_mpidr;
504 if (!(processor->flags & ACPI_MADT_ENABLED)) {
505 pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
509 if (hwid & ~MPIDR_HWID_BITMASK || hwid == INVALID_HWID) {
510 pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid);
514 if (is_mpidr_duplicate(cpu_count, hwid)) {
515 pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid);
519 /* Check if GICC structure of boot CPU is available in the MADT */
520 if (cpu_logical_map(0) == hwid) {
522 pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n",
526 bootcpu_valid = true;
527 cpu_madt_gicc[0] = *processor;
528 early_map_cpu_to_node(0, acpi_numa_get_nid(0, hwid));
532 if (cpu_count >= NR_CPUS)
535 /* map the logical cpu id to cpu MPIDR */
536 cpu_logical_map(cpu_count) = hwid;
538 cpu_madt_gicc[cpu_count] = *processor;
541 * Set-up the ACPI parking protocol cpu entries
542 * while initializing the cpu_logical_map to
543 * avoid parsing MADT entries multiple times for
544 * nothing (ie a valid cpu_logical_map entry should
545 * contain a valid parking protocol data set to
546 * initialize the cpu if the parking protocol is
547 * the only available enable method).
549 acpi_set_mailbox_entry(cpu_count, processor);
551 early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count, hwid));
557 acpi_parse_gic_cpu_interface(struct acpi_subtable_header *header,
558 const unsigned long end)
560 struct acpi_madt_generic_interrupt *processor;
562 processor = (struct acpi_madt_generic_interrupt *)header;
563 if (BAD_MADT_GICC_ENTRY(processor, end))
566 acpi_table_print_madt_entry(header);
568 acpi_map_gic_cpu_interface(processor);
573 #define acpi_table_parse_madt(...) do { } while (0)
577 * Enumerate the possible CPU set from the device tree and build the
578 * cpu logical map array containing MPIDR values related to logical
579 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
581 static void __init of_parse_and_init_cpus(void)
583 struct device_node *dn;
585 for_each_node_by_type(dn, "cpu") {
586 u64 hwid = of_get_cpu_mpidr(dn);
588 if (hwid == INVALID_HWID)
591 if (is_mpidr_duplicate(cpu_count, hwid)) {
592 pr_err("%pOF: duplicate cpu reg properties in the DT\n",
598 * The numbering scheme requires that the boot CPU
599 * must be assigned logical id 0. Record it so that
600 * the logical map built from DT is validated and can
603 if (hwid == cpu_logical_map(0)) {
605 pr_err("%pOF: duplicate boot cpu reg property in DT\n",
610 bootcpu_valid = true;
611 early_map_cpu_to_node(0, of_node_to_nid(dn));
614 * cpu_logical_map has already been
615 * initialized and the boot cpu doesn't need
616 * the enable-method so continue without
622 if (cpu_count >= NR_CPUS)
625 pr_debug("cpu logical map 0x%llx\n", hwid);
626 cpu_logical_map(cpu_count) = hwid;
628 early_map_cpu_to_node(cpu_count, of_node_to_nid(dn));
635 * Enumerate the possible CPU set from the device tree or ACPI and build the
636 * cpu logical map array containing MPIDR values related to logical
637 * cpus. Assumes that cpu_logical_map(0) has already been initialized.
639 void __init smp_init_cpus(void)
644 of_parse_and_init_cpus();
647 * do a walk of MADT to determine how many CPUs
648 * we have including disabled CPUs, and get information
649 * we need for SMP init
651 acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
652 acpi_parse_gic_cpu_interface, 0);
654 if (cpu_count > nr_cpu_ids)
655 pr_warn("Number of cores (%d) exceeds configured maximum of %u - clipping\n",
656 cpu_count, nr_cpu_ids);
658 if (!bootcpu_valid) {
659 pr_err("missing boot CPU MPIDR, not enabling secondaries\n");
664 * We need to set the cpu_logical_map entries before enabling
665 * the cpus so that cpu processor description entries (DT cpu nodes
666 * and ACPI MADT entries) can be retrieved by matching the cpu hwid
667 * with entries in cpu_logical_map while initializing the cpus.
668 * If the cpu set-up fails, invalidate the cpu_logical_map entry.
670 for (i = 1; i < nr_cpu_ids; i++) {
671 if (cpu_logical_map(i) != INVALID_HWID) {
672 if (smp_cpu_setup(i))
673 cpu_logical_map(i) = INVALID_HWID;
678 void __init smp_prepare_cpus(unsigned int max_cpus)
682 unsigned int this_cpu;
686 this_cpu = smp_processor_id();
687 store_cpu_topology(this_cpu);
688 numa_store_cpu_info(this_cpu);
691 * If UP is mandated by "nosmp" (which implies "maxcpus=0"), don't set
692 * secondary CPUs present.
698 * Initialise the present map (which describes the set of CPUs
699 * actually populated at the present time) and release the
700 * secondaries from the bootloader.
702 for_each_possible_cpu(cpu) {
704 per_cpu(cpu_number, cpu) = cpu;
706 if (cpu == smp_processor_id())
712 err = cpu_ops[cpu]->cpu_prepare(cpu);
716 set_cpu_present(cpu, true);
717 numa_store_cpu_info(cpu);
721 void (*__smp_cross_call)(const struct cpumask *, unsigned int);
723 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
725 __smp_cross_call = fn;
728 static const char *ipi_types[NR_IPI] __tracepoint_string = {
729 #define S(x,s) [x] = s
730 S(IPI_RESCHEDULE, "Rescheduling interrupts"),
731 S(IPI_CALL_FUNC, "Function call interrupts"),
732 S(IPI_CPU_STOP, "CPU stop interrupts"),
733 S(IPI_CPU_CRASH_STOP, "CPU stop (for crash dump) interrupts"),
734 S(IPI_TIMER, "Timer broadcast interrupts"),
735 S(IPI_IRQ_WORK, "IRQ work interrupts"),
736 S(IPI_WAKEUP, "CPU wake-up interrupts"),
739 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
741 trace_ipi_raise(target, ipi_types[ipinr]);
742 __smp_cross_call(target, ipinr);
745 void show_ipi_list(struct seq_file *p, int prec)
749 for (i = 0; i < NR_IPI; i++) {
750 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
751 prec >= 4 ? " " : "");
752 for_each_online_cpu(cpu)
753 seq_printf(p, "%10u ",
754 __get_irq_stat(cpu, ipi_irqs[i]));
755 seq_printf(p, " %s\n", ipi_types[i]);
759 u64 smp_irq_stat_cpu(unsigned int cpu)
764 for (i = 0; i < NR_IPI; i++)
765 sum += __get_irq_stat(cpu, ipi_irqs[i]);
770 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
772 smp_cross_call(mask, IPI_CALL_FUNC);
775 void arch_send_call_function_single_ipi(int cpu)
777 smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
780 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
781 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
783 smp_cross_call(mask, IPI_WAKEUP);
787 #ifdef CONFIG_IRQ_WORK
788 void arch_irq_work_raise(void)
790 if (__smp_cross_call)
791 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
796 * ipi_cpu_stop - handle IPI from smp_send_stop()
798 static void ipi_cpu_stop(unsigned int cpu)
800 set_cpu_online(cpu, false);
808 #ifdef CONFIG_KEXEC_CORE
809 static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
812 static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
814 #ifdef CONFIG_KEXEC_CORE
815 crash_save_cpu(regs, cpu);
817 atomic_dec(&waiting_for_crash_ipi);
821 #ifdef CONFIG_HOTPLUG_CPU
822 if (cpu_ops[cpu]->cpu_die)
823 cpu_ops[cpu]->cpu_die(cpu);
832 * Main handler for inter-processor interrupts
834 void handle_IPI(int ipinr, struct pt_regs *regs)
836 unsigned int cpu = smp_processor_id();
837 struct pt_regs *old_regs = set_irq_regs(regs);
839 if ((unsigned)ipinr < NR_IPI) {
840 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
841 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
851 generic_smp_call_function_interrupt();
861 case IPI_CPU_CRASH_STOP:
862 if (IS_ENABLED(CONFIG_KEXEC_CORE)) {
864 ipi_cpu_crash_stop(cpu, regs);
870 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
873 tick_receive_broadcast();
878 #ifdef CONFIG_IRQ_WORK
886 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
888 WARN_ONCE(!acpi_parking_protocol_valid(cpu),
889 "CPU%u: Wake-up IPI outside the ACPI parking protocol\n",
895 pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr);
899 if ((unsigned)ipinr < NR_IPI)
900 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
901 set_irq_regs(old_regs);
904 void smp_send_reschedule(int cpu)
906 smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
909 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
910 void tick_broadcast(const struct cpumask *mask)
912 smp_cross_call(mask, IPI_TIMER);
917 * The number of CPUs online, not counting this CPU (which may not be
918 * fully online and so not counted in num_online_cpus()).
920 static inline unsigned int num_other_online_cpus(void)
922 unsigned int this_cpu_online = cpu_online(smp_processor_id());
924 return num_online_cpus() - this_cpu_online;
927 void smp_send_stop(void)
929 unsigned long timeout;
931 if (num_other_online_cpus()) {
934 cpumask_copy(&mask, cpu_online_mask);
935 cpumask_clear_cpu(smp_processor_id(), &mask);
937 if (system_state <= SYSTEM_RUNNING)
938 pr_crit("SMP: stopping secondary CPUs\n");
939 smp_cross_call(&mask, IPI_CPU_STOP);
942 /* Wait up to one second for other CPUs to stop */
943 timeout = USEC_PER_SEC;
944 while (num_other_online_cpus() && timeout--)
947 if (num_other_online_cpus())
948 pr_warning("SMP: failed to stop secondary CPUs %*pbl\n",
949 cpumask_pr_args(cpu_online_mask));
952 #ifdef CONFIG_KEXEC_CORE
953 void crash_smp_send_stop(void)
955 static int cpus_stopped;
957 unsigned long timeout;
960 * This function can be called twice in panic path, but obviously
961 * we execute this only once.
969 * If this cpu is the only one alive at this point in time, online or
970 * not, there are no stop messages to be sent around, so just back out.
972 if (num_other_online_cpus() == 0)
975 cpumask_copy(&mask, cpu_online_mask);
976 cpumask_clear_cpu(smp_processor_id(), &mask);
978 atomic_set(&waiting_for_crash_ipi, num_other_online_cpus());
980 pr_crit("SMP: stopping secondary CPUs\n");
981 smp_cross_call(&mask, IPI_CPU_CRASH_STOP);
983 /* Wait up to one second for other CPUs to stop */
984 timeout = USEC_PER_SEC;
985 while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--)
988 if (atomic_read(&waiting_for_crash_ipi) > 0)
989 pr_warning("SMP: failed to stop secondary CPUs %*pbl\n",
990 cpumask_pr_args(&mask));
993 bool smp_crash_stop_failed(void)
995 return (atomic_read(&waiting_for_crash_ipi) > 0);
1000 * not supported here
1002 int setup_profiling_timer(unsigned int multiplier)
1007 static bool have_cpu_die(void)
1009 #ifdef CONFIG_HOTPLUG_CPU
1010 int any_cpu = raw_smp_processor_id();
1012 if (cpu_ops[any_cpu] && cpu_ops[any_cpu]->cpu_die)
1018 bool cpus_are_stuck_in_kernel(void)
1020 bool smp_spin_tables = (num_possible_cpus() > 1 && !have_cpu_die());
1022 return !!cpus_stuck_in_kernel || smp_spin_tables;