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Linux/arch/arm64/kernel/smp.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * SMP initialisation and IPI support
  4  * Based on arch/arm/kernel/smp.c
  5  *
  6  * Copyright (C) 2012 ARM Ltd.
  7  */
  8 
  9 #include <linux/acpi.h>
 10 #include <linux/arm_sdei.h>
 11 #include <linux/delay.h>
 12 #include <linux/init.h>
 13 #include <linux/spinlock.h>
 14 #include <linux/sched/mm.h>
 15 #include <linux/sched/hotplug.h>
 16 #include <linux/sched/task_stack.h>
 17 #include <linux/interrupt.h>
 18 #include <linux/cache.h>
 19 #include <linux/profile.h>
 20 #include <linux/errno.h>
 21 #include <linux/mm.h>
 22 #include <linux/err.h>
 23 #include <linux/cpu.h>
 24 #include <linux/smp.h>
 25 #include <linux/seq_file.h>
 26 #include <linux/irq.h>
 27 #include <linux/irqchip/arm-gic-v3.h>
 28 #include <linux/percpu.h>
 29 #include <linux/clockchips.h>
 30 #include <linux/completion.h>
 31 #include <linux/of.h>
 32 #include <linux/irq_work.h>
 33 #include <linux/kexec.h>
 34 #include <linux/kvm_host.h>
 35 
 36 #include <asm/alternative.h>
 37 #include <asm/atomic.h>
 38 #include <asm/cacheflush.h>
 39 #include <asm/cpu.h>
 40 #include <asm/cputype.h>
 41 #include <asm/cpu_ops.h>
 42 #include <asm/daifflags.h>
 43 #include <asm/kvm_mmu.h>
 44 #include <asm/mmu_context.h>
 45 #include <asm/numa.h>
 46 #include <asm/pgtable.h>
 47 #include <asm/pgalloc.h>
 48 #include <asm/processor.h>
 49 #include <asm/smp_plat.h>
 50 #include <asm/sections.h>
 51 #include <asm/tlbflush.h>
 52 #include <asm/ptrace.h>
 53 #include <asm/virt.h>
 54 
 55 #define CREATE_TRACE_POINTS
 56 #include <trace/events/ipi.h>
 57 
 58 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
 59 EXPORT_PER_CPU_SYMBOL(cpu_number);
 60 
 61 /*
 62  * as from 2.5, kernels no longer have an init_tasks structure
 63  * so we need some other way of telling a new secondary core
 64  * where to place its SVC stack
 65  */
 66 struct secondary_data secondary_data;
 67 /* Number of CPUs which aren't online, but looping in kernel text. */
 68 int cpus_stuck_in_kernel;
 69 
 70 enum ipi_msg_type {
 71         IPI_RESCHEDULE,
 72         IPI_CALL_FUNC,
 73         IPI_CPU_STOP,
 74         IPI_CPU_CRASH_STOP,
 75         IPI_TIMER,
 76         IPI_IRQ_WORK,
 77         IPI_WAKEUP
 78 };
 79 
 80 #ifdef CONFIG_HOTPLUG_CPU
 81 static int op_cpu_kill(unsigned int cpu);
 82 #else
 83 static inline int op_cpu_kill(unsigned int cpu)
 84 {
 85         return -ENOSYS;
 86 }
 87 #endif
 88 
 89 
 90 /*
 91  * Boot a secondary CPU, and assign it the specified idle task.
 92  * This also gives us the initial stack to use for this CPU.
 93  */
 94 static int boot_secondary(unsigned int cpu, struct task_struct *idle)
 95 {
 96         if (cpu_ops[cpu]->cpu_boot)
 97                 return cpu_ops[cpu]->cpu_boot(cpu);
 98 
 99         return -EOPNOTSUPP;
100 }
101 
102 static DECLARE_COMPLETION(cpu_running);
103 
104 int __cpu_up(unsigned int cpu, struct task_struct *idle)
105 {
106         int ret;
107         long status;
108 
109         /*
110          * We need to tell the secondary core where to find its stack and the
111          * page tables.
112          */
113         secondary_data.task = idle;
114         secondary_data.stack = task_stack_page(idle) + THREAD_SIZE;
115         update_cpu_boot_status(CPU_MMU_OFF);
116         __flush_dcache_area(&secondary_data, sizeof(secondary_data));
117 
118         /*
119          * Now bring the CPU into our world.
120          */
121         ret = boot_secondary(cpu, idle);
122         if (ret == 0) {
123                 /*
124                  * CPU was successfully started, wait for it to come online or
125                  * time out.
126                  */
127                 wait_for_completion_timeout(&cpu_running,
128                                             msecs_to_jiffies(5000));
129 
130                 if (!cpu_online(cpu)) {
131                         pr_crit("CPU%u: failed to come online\n", cpu);
132                         ret = -EIO;
133                 }
134         } else {
135                 pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
136                 return ret;
137         }
138 
139         secondary_data.task = NULL;
140         secondary_data.stack = NULL;
141         __flush_dcache_area(&secondary_data, sizeof(secondary_data));
142         status = READ_ONCE(secondary_data.status);
143         if (ret && status) {
144 
145                 if (status == CPU_MMU_OFF)
146                         status = READ_ONCE(__early_cpu_boot_status);
147 
148                 switch (status & CPU_BOOT_STATUS_MASK) {
149                 default:
150                         pr_err("CPU%u: failed in unknown state : 0x%lx\n",
151                                         cpu, status);
152                         cpus_stuck_in_kernel++;
153                         break;
154                 case CPU_KILL_ME:
155                         if (!op_cpu_kill(cpu)) {
156                                 pr_crit("CPU%u: died during early boot\n", cpu);
157                                 break;
158                         }
159                         pr_crit("CPU%u: may not have shut down cleanly\n", cpu);
160                         /* Fall through */
161                 case CPU_STUCK_IN_KERNEL:
162                         pr_crit("CPU%u: is stuck in kernel\n", cpu);
163                         if (status & CPU_STUCK_REASON_52_BIT_VA)
164                                 pr_crit("CPU%u: does not support 52-bit VAs\n", cpu);
165                         if (status & CPU_STUCK_REASON_NO_GRAN)
166                                 pr_crit("CPU%u: does not support %luK granule \n", cpu, PAGE_SIZE / SZ_1K);
167                         cpus_stuck_in_kernel++;
168                         break;
169                 case CPU_PANIC_KERNEL:
170                         panic("CPU%u detected unsupported configuration\n", cpu);
171                 }
172         }
173 
174         return ret;
175 }
176 
177 static void init_gic_priority_masking(void)
178 {
179         u32 cpuflags;
180 
181         if (WARN_ON(!gic_enable_sre()))
182                 return;
183 
184         cpuflags = read_sysreg(daif);
185 
186         WARN_ON(!(cpuflags & PSR_I_BIT));
187 
188         gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
189 }
190 
191 /*
192  * This is the secondary CPU boot entry.  We're using this CPUs
193  * idle thread stack, but a set of temporary page tables.
194  */
195 asmlinkage notrace void secondary_start_kernel(void)
196 {
197         u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
198         struct mm_struct *mm = &init_mm;
199         unsigned int cpu;
200 
201         cpu = task_cpu(current);
202         set_my_cpu_offset(per_cpu_offset(cpu));
203 
204         /*
205          * All kernel threads share the same mm context; grab a
206          * reference and switch to it.
207          */
208         mmgrab(mm);
209         current->active_mm = mm;
210 
211         /*
212          * TTBR0 is only used for the identity mapping at this stage. Make it
213          * point to zero page to avoid speculatively fetching new entries.
214          */
215         cpu_uninstall_idmap();
216 
217         if (system_uses_irq_prio_masking())
218                 init_gic_priority_masking();
219 
220         preempt_disable();
221         trace_hardirqs_off();
222 
223         /*
224          * If the system has established the capabilities, make sure
225          * this CPU ticks all of those. If it doesn't, the CPU will
226          * fail to come online.
227          */
228         check_local_cpu_capabilities();
229 
230         if (cpu_ops[cpu]->cpu_postboot)
231                 cpu_ops[cpu]->cpu_postboot();
232 
233         /*
234          * Log the CPU info before it is marked online and might get read.
235          */
236         cpuinfo_store_cpu();
237 
238         /*
239          * Enable GIC and timers.
240          */
241         notify_cpu_starting(cpu);
242 
243         store_cpu_topology(cpu);
244         numa_add_cpu(cpu);
245 
246         /*
247          * OK, now it's safe to let the boot CPU continue.  Wait for
248          * the CPU migration code to notice that the CPU is online
249          * before we continue.
250          */
251         pr_info("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n",
252                                          cpu, (unsigned long)mpidr,
253                                          read_cpuid_id());
254         update_cpu_boot_status(CPU_BOOT_SUCCESS);
255         set_cpu_online(cpu, true);
256         complete(&cpu_running);
257 
258         local_daif_restore(DAIF_PROCCTX);
259 
260         /*
261          * OK, it's off to the idle thread for us
262          */
263         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
264 }
265 
266 #ifdef CONFIG_HOTPLUG_CPU
267 static int op_cpu_disable(unsigned int cpu)
268 {
269         /*
270          * If we don't have a cpu_die method, abort before we reach the point
271          * of no return. CPU0 may not have an cpu_ops, so test for it.
272          */
273         if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_die)
274                 return -EOPNOTSUPP;
275 
276         /*
277          * We may need to abort a hot unplug for some other mechanism-specific
278          * reason.
279          */
280         if (cpu_ops[cpu]->cpu_disable)
281                 return cpu_ops[cpu]->cpu_disable(cpu);
282 
283         return 0;
284 }
285 
286 /*
287  * __cpu_disable runs on the processor to be shutdown.
288  */
289 int __cpu_disable(void)
290 {
291         unsigned int cpu = smp_processor_id();
292         int ret;
293 
294         ret = op_cpu_disable(cpu);
295         if (ret)
296                 return ret;
297 
298         remove_cpu_topology(cpu);
299         numa_remove_cpu(cpu);
300 
301         /*
302          * Take this CPU offline.  Once we clear this, we can't return,
303          * and we must not schedule until we're ready to give up the cpu.
304          */
305         set_cpu_online(cpu, false);
306 
307         /*
308          * OK - migrate IRQs away from this CPU
309          */
310         irq_migrate_all_off_this_cpu();
311 
312         return 0;
313 }
314 
315 static int op_cpu_kill(unsigned int cpu)
316 {
317         /*
318          * If we have no means of synchronising with the dying CPU, then assume
319          * that it is really dead. We can only wait for an arbitrary length of
320          * time and hope that it's dead, so let's skip the wait and just hope.
321          */
322         if (!cpu_ops[cpu]->cpu_kill)
323                 return 0;
324 
325         return cpu_ops[cpu]->cpu_kill(cpu);
326 }
327 
328 /*
329  * called on the thread which is asking for a CPU to be shutdown -
330  * waits until shutdown has completed, or it is timed out.
331  */
332 void __cpu_die(unsigned int cpu)
333 {
334         int err;
335 
336         if (!cpu_wait_death(cpu, 5)) {
337                 pr_crit("CPU%u: cpu didn't die\n", cpu);
338                 return;
339         }
340         pr_notice("CPU%u: shutdown\n", cpu);
341 
342         /*
343          * Now that the dying CPU is beyond the point of no return w.r.t.
344          * in-kernel synchronisation, try to get the firwmare to help us to
345          * verify that it has really left the kernel before we consider
346          * clobbering anything it might still be using.
347          */
348         err = op_cpu_kill(cpu);
349         if (err)
350                 pr_warn("CPU%d may not have shut down cleanly: %d\n", cpu, err);
351 }
352 
353 /*
354  * Called from the idle thread for the CPU which has been shutdown.
355  *
356  */
357 void cpu_die(void)
358 {
359         unsigned int cpu = smp_processor_id();
360 
361         idle_task_exit();
362 
363         local_daif_mask();
364 
365         /* Tell __cpu_die() that this CPU is now safe to dispose of */
366         (void)cpu_report_death();
367 
368         /*
369          * Actually shutdown the CPU. This must never fail. The specific hotplug
370          * mechanism must perform all required cache maintenance to ensure that
371          * no dirty lines are lost in the process of shutting down the CPU.
372          */
373         cpu_ops[cpu]->cpu_die(cpu);
374 
375         BUG();
376 }
377 #endif
378 
379 /*
380  * Kill the calling secondary CPU, early in bringup before it is turned
381  * online.
382  */
383 void cpu_die_early(void)
384 {
385         int cpu = smp_processor_id();
386 
387         pr_crit("CPU%d: will not boot\n", cpu);
388 
389         /* Mark this CPU absent */
390         set_cpu_present(cpu, 0);
391 
392 #ifdef CONFIG_HOTPLUG_CPU
393         update_cpu_boot_status(CPU_KILL_ME);
394         /* Check if we can park ourselves */
395         if (cpu_ops[cpu] && cpu_ops[cpu]->cpu_die)
396                 cpu_ops[cpu]->cpu_die(cpu);
397 #endif
398         update_cpu_boot_status(CPU_STUCK_IN_KERNEL);
399 
400         cpu_park_loop();
401 }
402 
403 static void __init hyp_mode_check(void)
404 {
405         if (is_hyp_mode_available())
406                 pr_info("CPU: All CPU(s) started at EL2\n");
407         else if (is_hyp_mode_mismatched())
408                 WARN_TAINT(1, TAINT_CPU_OUT_OF_SPEC,
409                            "CPU: CPUs started in inconsistent modes");
410         else
411                 pr_info("CPU: All CPU(s) started at EL1\n");
412         if (IS_ENABLED(CONFIG_KVM_ARM_HOST))
413                 kvm_compute_layout();
414 }
415 
416 void __init smp_cpus_done(unsigned int max_cpus)
417 {
418         pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
419         setup_cpu_features();
420         hyp_mode_check();
421         apply_alternatives_all();
422         mark_linear_text_alias_ro();
423 }
424 
425 void __init smp_prepare_boot_cpu(void)
426 {
427         set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
428         cpuinfo_store_boot_cpu();
429 
430         /*
431          * We now know enough about the boot CPU to apply the
432          * alternatives that cannot wait until interrupt handling
433          * and/or scheduling is enabled.
434          */
435         apply_boot_alternatives();
436 
437         /* Conditionally switch to GIC PMR for interrupt masking */
438         if (system_uses_irq_prio_masking())
439                 init_gic_priority_masking();
440 }
441 
442 static u64 __init of_get_cpu_mpidr(struct device_node *dn)
443 {
444         const __be32 *cell;
445         u64 hwid;
446 
447         /*
448          * A cpu node with missing "reg" property is
449          * considered invalid to build a cpu_logical_map
450          * entry.
451          */
452         cell = of_get_property(dn, "reg", NULL);
453         if (!cell) {
454                 pr_err("%pOF: missing reg property\n", dn);
455                 return INVALID_HWID;
456         }
457 
458         hwid = of_read_number(cell, of_n_addr_cells(dn));
459         /*
460          * Non affinity bits must be set to 0 in the DT
461          */
462         if (hwid & ~MPIDR_HWID_BITMASK) {
463                 pr_err("%pOF: invalid reg property\n", dn);
464                 return INVALID_HWID;
465         }
466         return hwid;
467 }
468 
469 /*
470  * Duplicate MPIDRs are a recipe for disaster. Scan all initialized
471  * entries and check for duplicates. If any is found just ignore the
472  * cpu. cpu_logical_map was initialized to INVALID_HWID to avoid
473  * matching valid MPIDR values.
474  */
475 static bool __init is_mpidr_duplicate(unsigned int cpu, u64 hwid)
476 {
477         unsigned int i;
478 
479         for (i = 1; (i < cpu) && (i < NR_CPUS); i++)
480                 if (cpu_logical_map(i) == hwid)
481                         return true;
482         return false;
483 }
484 
485 /*
486  * Initialize cpu operations for a logical cpu and
487  * set it in the possible mask on success
488  */
489 static int __init smp_cpu_setup(int cpu)
490 {
491         if (cpu_read_ops(cpu))
492                 return -ENODEV;
493 
494         if (cpu_ops[cpu]->cpu_init(cpu))
495                 return -ENODEV;
496 
497         set_cpu_possible(cpu, true);
498 
499         return 0;
500 }
501 
502 static bool bootcpu_valid __initdata;
503 static unsigned int cpu_count = 1;
504 
505 #ifdef CONFIG_ACPI
506 static struct acpi_madt_generic_interrupt cpu_madt_gicc[NR_CPUS];
507 
508 struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu)
509 {
510         return &cpu_madt_gicc[cpu];
511 }
512 
513 /*
514  * acpi_map_gic_cpu_interface - parse processor MADT entry
515  *
516  * Carry out sanity checks on MADT processor entry and initialize
517  * cpu_logical_map on success
518  */
519 static void __init
520 acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
521 {
522         u64 hwid = processor->arm_mpidr;
523 
524         if (!(processor->flags & ACPI_MADT_ENABLED)) {
525                 pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
526                 return;
527         }
528 
529         if (hwid & ~MPIDR_HWID_BITMASK || hwid == INVALID_HWID) {
530                 pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid);
531                 return;
532         }
533 
534         if (is_mpidr_duplicate(cpu_count, hwid)) {
535                 pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid);
536                 return;
537         }
538 
539         /* Check if GICC structure of boot CPU is available in the MADT */
540         if (cpu_logical_map(0) == hwid) {
541                 if (bootcpu_valid) {
542                         pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n",
543                                hwid);
544                         return;
545                 }
546                 bootcpu_valid = true;
547                 cpu_madt_gicc[0] = *processor;
548                 return;
549         }
550 
551         if (cpu_count >= NR_CPUS)
552                 return;
553 
554         /* map the logical cpu id to cpu MPIDR */
555         cpu_logical_map(cpu_count) = hwid;
556 
557         cpu_madt_gicc[cpu_count] = *processor;
558 
559         /*
560          * Set-up the ACPI parking protocol cpu entries
561          * while initializing the cpu_logical_map to
562          * avoid parsing MADT entries multiple times for
563          * nothing (ie a valid cpu_logical_map entry should
564          * contain a valid parking protocol data set to
565          * initialize the cpu if the parking protocol is
566          * the only available enable method).
567          */
568         acpi_set_mailbox_entry(cpu_count, processor);
569 
570         cpu_count++;
571 }
572 
573 static int __init
574 acpi_parse_gic_cpu_interface(union acpi_subtable_headers *header,
575                              const unsigned long end)
576 {
577         struct acpi_madt_generic_interrupt *processor;
578 
579         processor = (struct acpi_madt_generic_interrupt *)header;
580         if (BAD_MADT_GICC_ENTRY(processor, end))
581                 return -EINVAL;
582 
583         acpi_table_print_madt_entry(&header->common);
584 
585         acpi_map_gic_cpu_interface(processor);
586 
587         return 0;
588 }
589 
590 static void __init acpi_parse_and_init_cpus(void)
591 {
592         int i;
593 
594         /*
595          * do a walk of MADT to determine how many CPUs
596          * we have including disabled CPUs, and get information
597          * we need for SMP init.
598          */
599         acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
600                                       acpi_parse_gic_cpu_interface, 0);
601 
602         /*
603          * In ACPI, SMP and CPU NUMA information is provided in separate
604          * static tables, namely the MADT and the SRAT.
605          *
606          * Thus, it is simpler to first create the cpu logical map through
607          * an MADT walk and then map the logical cpus to their node ids
608          * as separate steps.
609          */
610         acpi_map_cpus_to_nodes();
611 
612         for (i = 0; i < nr_cpu_ids; i++)
613                 early_map_cpu_to_node(i, acpi_numa_get_nid(i));
614 }
615 #else
616 #define acpi_parse_and_init_cpus(...)   do { } while (0)
617 #endif
618 
619 /*
620  * Enumerate the possible CPU set from the device tree and build the
621  * cpu logical map array containing MPIDR values related to logical
622  * cpus. Assumes that cpu_logical_map(0) has already been initialized.
623  */
624 static void __init of_parse_and_init_cpus(void)
625 {
626         struct device_node *dn;
627 
628         for_each_of_cpu_node(dn) {
629                 u64 hwid = of_get_cpu_mpidr(dn);
630 
631                 if (hwid == INVALID_HWID)
632                         goto next;
633 
634                 if (is_mpidr_duplicate(cpu_count, hwid)) {
635                         pr_err("%pOF: duplicate cpu reg properties in the DT\n",
636                                 dn);
637                         goto next;
638                 }
639 
640                 /*
641                  * The numbering scheme requires that the boot CPU
642                  * must be assigned logical id 0. Record it so that
643                  * the logical map built from DT is validated and can
644                  * be used.
645                  */
646                 if (hwid == cpu_logical_map(0)) {
647                         if (bootcpu_valid) {
648                                 pr_err("%pOF: duplicate boot cpu reg property in DT\n",
649                                         dn);
650                                 goto next;
651                         }
652 
653                         bootcpu_valid = true;
654                         early_map_cpu_to_node(0, of_node_to_nid(dn));
655 
656                         /*
657                          * cpu_logical_map has already been
658                          * initialized and the boot cpu doesn't need
659                          * the enable-method so continue without
660                          * incrementing cpu.
661                          */
662                         continue;
663                 }
664 
665                 if (cpu_count >= NR_CPUS)
666                         goto next;
667 
668                 pr_debug("cpu logical map 0x%llx\n", hwid);
669                 cpu_logical_map(cpu_count) = hwid;
670 
671                 early_map_cpu_to_node(cpu_count, of_node_to_nid(dn));
672 next:
673                 cpu_count++;
674         }
675 }
676 
677 /*
678  * Enumerate the possible CPU set from the device tree or ACPI and build the
679  * cpu logical map array containing MPIDR values related to logical
680  * cpus. Assumes that cpu_logical_map(0) has already been initialized.
681  */
682 void __init smp_init_cpus(void)
683 {
684         int i;
685 
686         if (acpi_disabled)
687                 of_parse_and_init_cpus();
688         else
689                 acpi_parse_and_init_cpus();
690 
691         if (cpu_count > nr_cpu_ids)
692                 pr_warn("Number of cores (%d) exceeds configured maximum of %u - clipping\n",
693                         cpu_count, nr_cpu_ids);
694 
695         if (!bootcpu_valid) {
696                 pr_err("missing boot CPU MPIDR, not enabling secondaries\n");
697                 return;
698         }
699 
700         /*
701          * We need to set the cpu_logical_map entries before enabling
702          * the cpus so that cpu processor description entries (DT cpu nodes
703          * and ACPI MADT entries) can be retrieved by matching the cpu hwid
704          * with entries in cpu_logical_map while initializing the cpus.
705          * If the cpu set-up fails, invalidate the cpu_logical_map entry.
706          */
707         for (i = 1; i < nr_cpu_ids; i++) {
708                 if (cpu_logical_map(i) != INVALID_HWID) {
709                         if (smp_cpu_setup(i))
710                                 cpu_logical_map(i) = INVALID_HWID;
711                 }
712         }
713 }
714 
715 void __init smp_prepare_cpus(unsigned int max_cpus)
716 {
717         int err;
718         unsigned int cpu;
719         unsigned int this_cpu;
720 
721         init_cpu_topology();
722 
723         this_cpu = smp_processor_id();
724         store_cpu_topology(this_cpu);
725         numa_store_cpu_info(this_cpu);
726         numa_add_cpu(this_cpu);
727 
728         /*
729          * If UP is mandated by "nosmp" (which implies "maxcpus=0"), don't set
730          * secondary CPUs present.
731          */
732         if (max_cpus == 0)
733                 return;
734 
735         /*
736          * Initialise the present map (which describes the set of CPUs
737          * actually populated at the present time) and release the
738          * secondaries from the bootloader.
739          */
740         for_each_possible_cpu(cpu) {
741 
742                 per_cpu(cpu_number, cpu) = cpu;
743 
744                 if (cpu == smp_processor_id())
745                         continue;
746 
747                 if (!cpu_ops[cpu])
748                         continue;
749 
750                 err = cpu_ops[cpu]->cpu_prepare(cpu);
751                 if (err)
752                         continue;
753 
754                 set_cpu_present(cpu, true);
755                 numa_store_cpu_info(cpu);
756         }
757 }
758 
759 void (*__smp_cross_call)(const struct cpumask *, unsigned int);
760 
761 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
762 {
763         __smp_cross_call = fn;
764 }
765 
766 static const char *ipi_types[NR_IPI] __tracepoint_string = {
767 #define S(x,s)  [x] = s
768         S(IPI_RESCHEDULE, "Rescheduling interrupts"),
769         S(IPI_CALL_FUNC, "Function call interrupts"),
770         S(IPI_CPU_STOP, "CPU stop interrupts"),
771         S(IPI_CPU_CRASH_STOP, "CPU stop (for crash dump) interrupts"),
772         S(IPI_TIMER, "Timer broadcast interrupts"),
773         S(IPI_IRQ_WORK, "IRQ work interrupts"),
774         S(IPI_WAKEUP, "CPU wake-up interrupts"),
775 };
776 
777 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
778 {
779         trace_ipi_raise(target, ipi_types[ipinr]);
780         __smp_cross_call(target, ipinr);
781 }
782 
783 void show_ipi_list(struct seq_file *p, int prec)
784 {
785         unsigned int cpu, i;
786 
787         for (i = 0; i < NR_IPI; i++) {
788                 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
789                            prec >= 4 ? " " : "");
790                 for_each_online_cpu(cpu)
791                         seq_printf(p, "%10u ",
792                                    __get_irq_stat(cpu, ipi_irqs[i]));
793                 seq_printf(p, "      %s\n", ipi_types[i]);
794         }
795 }
796 
797 u64 smp_irq_stat_cpu(unsigned int cpu)
798 {
799         u64 sum = 0;
800         int i;
801 
802         for (i = 0; i < NR_IPI; i++)
803                 sum += __get_irq_stat(cpu, ipi_irqs[i]);
804 
805         return sum;
806 }
807 
808 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
809 {
810         smp_cross_call(mask, IPI_CALL_FUNC);
811 }
812 
813 void arch_send_call_function_single_ipi(int cpu)
814 {
815         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
816 }
817 
818 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
819 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
820 {
821         smp_cross_call(mask, IPI_WAKEUP);
822 }
823 #endif
824 
825 #ifdef CONFIG_IRQ_WORK
826 void arch_irq_work_raise(void)
827 {
828         if (__smp_cross_call)
829                 smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
830 }
831 #endif
832 
833 static void local_cpu_stop(void)
834 {
835         set_cpu_online(smp_processor_id(), false);
836 
837         local_daif_mask();
838         sdei_mask_local_cpu();
839         cpu_park_loop();
840 }
841 
842 /*
843  * We need to implement panic_smp_self_stop() for parallel panic() calls, so
844  * that cpu_online_mask gets correctly updated and smp_send_stop() can skip
845  * CPUs that have already stopped themselves.
846  */
847 void panic_smp_self_stop(void)
848 {
849         local_cpu_stop();
850 }
851 
852 #ifdef CONFIG_KEXEC_CORE
853 static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
854 #endif
855 
856 static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
857 {
858 #ifdef CONFIG_KEXEC_CORE
859         crash_save_cpu(regs, cpu);
860 
861         atomic_dec(&waiting_for_crash_ipi);
862 
863         local_irq_disable();
864         sdei_mask_local_cpu();
865 
866 #ifdef CONFIG_HOTPLUG_CPU
867         if (cpu_ops[cpu]->cpu_die)
868                 cpu_ops[cpu]->cpu_die(cpu);
869 #endif
870 
871         /* just in case */
872         cpu_park_loop();
873 #endif
874 }
875 
876 /*
877  * Main handler for inter-processor interrupts
878  */
879 void handle_IPI(int ipinr, struct pt_regs *regs)
880 {
881         unsigned int cpu = smp_processor_id();
882         struct pt_regs *old_regs = set_irq_regs(regs);
883 
884         if ((unsigned)ipinr < NR_IPI) {
885                 trace_ipi_entry_rcuidle(ipi_types[ipinr]);
886                 __inc_irq_stat(cpu, ipi_irqs[ipinr]);
887         }
888 
889         switch (ipinr) {
890         case IPI_RESCHEDULE:
891                 scheduler_ipi();
892                 break;
893 
894         case IPI_CALL_FUNC:
895                 irq_enter();
896                 generic_smp_call_function_interrupt();
897                 irq_exit();
898                 break;
899 
900         case IPI_CPU_STOP:
901                 irq_enter();
902                 local_cpu_stop();
903                 irq_exit();
904                 break;
905 
906         case IPI_CPU_CRASH_STOP:
907                 if (IS_ENABLED(CONFIG_KEXEC_CORE)) {
908                         irq_enter();
909                         ipi_cpu_crash_stop(cpu, regs);
910 
911                         unreachable();
912                 }
913                 break;
914 
915 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
916         case IPI_TIMER:
917                 irq_enter();
918                 tick_receive_broadcast();
919                 irq_exit();
920                 break;
921 #endif
922 
923 #ifdef CONFIG_IRQ_WORK
924         case IPI_IRQ_WORK:
925                 irq_enter();
926                 irq_work_run();
927                 irq_exit();
928                 break;
929 #endif
930 
931 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
932         case IPI_WAKEUP:
933                 WARN_ONCE(!acpi_parking_protocol_valid(cpu),
934                           "CPU%u: Wake-up IPI outside the ACPI parking protocol\n",
935                           cpu);
936                 break;
937 #endif
938 
939         default:
940                 pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr);
941                 break;
942         }
943 
944         if ((unsigned)ipinr < NR_IPI)
945                 trace_ipi_exit_rcuidle(ipi_types[ipinr]);
946         set_irq_regs(old_regs);
947 }
948 
949 void smp_send_reschedule(int cpu)
950 {
951         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
952 }
953 
954 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
955 void tick_broadcast(const struct cpumask *mask)
956 {
957         smp_cross_call(mask, IPI_TIMER);
958 }
959 #endif
960 
961 /*
962  * The number of CPUs online, not counting this CPU (which may not be
963  * fully online and so not counted in num_online_cpus()).
964  */
965 static inline unsigned int num_other_online_cpus(void)
966 {
967         unsigned int this_cpu_online = cpu_online(smp_processor_id());
968 
969         return num_online_cpus() - this_cpu_online;
970 }
971 
972 void smp_send_stop(void)
973 {
974         unsigned long timeout;
975 
976         if (num_other_online_cpus()) {
977                 cpumask_t mask;
978 
979                 cpumask_copy(&mask, cpu_online_mask);
980                 cpumask_clear_cpu(smp_processor_id(), &mask);
981 
982                 if (system_state <= SYSTEM_RUNNING)
983                         pr_crit("SMP: stopping secondary CPUs\n");
984                 smp_cross_call(&mask, IPI_CPU_STOP);
985         }
986 
987         /* Wait up to one second for other CPUs to stop */
988         timeout = USEC_PER_SEC;
989         while (num_other_online_cpus() && timeout--)
990                 udelay(1);
991 
992         if (num_other_online_cpus())
993                 pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
994                         cpumask_pr_args(cpu_online_mask));
995 
996         sdei_mask_local_cpu();
997 }
998 
999 #ifdef CONFIG_KEXEC_CORE
1000 void crash_smp_send_stop(void)
1001 {
1002         static int cpus_stopped;
1003         cpumask_t mask;
1004         unsigned long timeout;
1005 
1006         /*
1007          * This function can be called twice in panic path, but obviously
1008          * we execute this only once.
1009          */
1010         if (cpus_stopped)
1011                 return;
1012 
1013         cpus_stopped = 1;
1014 
1015         /*
1016          * If this cpu is the only one alive at this point in time, online or
1017          * not, there are no stop messages to be sent around, so just back out.
1018          */
1019         if (num_other_online_cpus() == 0) {
1020                 sdei_mask_local_cpu();
1021                 return;
1022         }
1023 
1024         cpumask_copy(&mask, cpu_online_mask);
1025         cpumask_clear_cpu(smp_processor_id(), &mask);
1026 
1027         atomic_set(&waiting_for_crash_ipi, num_other_online_cpus());
1028 
1029         pr_crit("SMP: stopping secondary CPUs\n");
1030         smp_cross_call(&mask, IPI_CPU_CRASH_STOP);
1031 
1032         /* Wait up to one second for other CPUs to stop */
1033         timeout = USEC_PER_SEC;
1034         while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--)
1035                 udelay(1);
1036 
1037         if (atomic_read(&waiting_for_crash_ipi) > 0)
1038                 pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
1039                         cpumask_pr_args(&mask));
1040 
1041         sdei_mask_local_cpu();
1042 }
1043 
1044 bool smp_crash_stop_failed(void)
1045 {
1046         return (atomic_read(&waiting_for_crash_ipi) > 0);
1047 }
1048 #endif
1049 
1050 /*
1051  * not supported here
1052  */
1053 int setup_profiling_timer(unsigned int multiplier)
1054 {
1055         return -EINVAL;
1056 }
1057 
1058 static bool have_cpu_die(void)
1059 {
1060 #ifdef CONFIG_HOTPLUG_CPU
1061         int any_cpu = raw_smp_processor_id();
1062 
1063         if (cpu_ops[any_cpu] && cpu_ops[any_cpu]->cpu_die)
1064                 return true;
1065 #endif
1066         return false;
1067 }
1068 
1069 bool cpus_are_stuck_in_kernel(void)
1070 {
1071         bool smp_spin_tables = (num_possible_cpus() > 1 && !have_cpu_die());
1072 
1073         return !!cpus_stuck_in_kernel || smp_spin_tables;
1074 }
1075 

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