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/kernel_stat.h>
34 #include <linux/kexec.h>
35 #include <linux/kvm_host.h>
36 
37 #include <asm/alternative.h>
38 #include <asm/atomic.h>
39 #include <asm/cacheflush.h>
40 #include <asm/cpu.h>
41 #include <asm/cputype.h>
42 #include <asm/cpu_ops.h>
43 #include <asm/daifflags.h>
44 #include <asm/kvm_mmu.h>
45 #include <asm/mmu_context.h>
46 #include <asm/numa.h>
47 #include <asm/processor.h>
48 #include <asm/smp_plat.h>
49 #include <asm/sections.h>
50 #include <asm/tlbflush.h>
51 #include <asm/ptrace.h>
52 #include <asm/virt.h>
53 
54 #define CREATE_TRACE_POINTS
55 #include <trace/events/ipi.h>
56 
57 DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number);
58 EXPORT_PER_CPU_SYMBOL(cpu_number);
59 
60 /*
61  * as from 2.5, kernels no longer have an init_tasks structure
62  * so we need some other way of telling a new secondary core
63  * where to place its SVC stack
64  */
65 struct secondary_data secondary_data;
66 /* Number of CPUs which aren't online, but looping in kernel text. */
67 static int cpus_stuck_in_kernel;
68 
69 enum ipi_msg_type {
70 	IPI_RESCHEDULE,
71 	IPI_CALL_FUNC,
72 	IPI_CPU_STOP,
73 	IPI_CPU_CRASH_STOP,
74 	IPI_TIMER,
75 	IPI_IRQ_WORK,
76 	IPI_WAKEUP,
77 	NR_IPI
78 };
79 
80 static int ipi_irq_base __read_mostly;
81 static int nr_ipi __read_mostly = NR_IPI;
82 static struct irq_desc *ipi_desc[NR_IPI] __read_mostly;
83 
84 static void ipi_setup(int cpu);
85 
86 #ifdef CONFIG_HOTPLUG_CPU
87 static void ipi_teardown(int cpu);
88 static int op_cpu_kill(unsigned int cpu);
89 #else
op_cpu_kill(unsigned int cpu)90 static inline int op_cpu_kill(unsigned int cpu)
91 {
92 	return -ENOSYS;
93 }
94 #endif
95 
96 
97 /*
98  * Boot a secondary CPU, and assign it the specified idle task.
99  * This also gives us the initial stack to use for this CPU.
100  */
boot_secondary(unsigned int cpu,struct task_struct * idle)101 static int boot_secondary(unsigned int cpu, struct task_struct *idle)
102 {
103 	const struct cpu_operations *ops = get_cpu_ops(cpu);
104 
105 	if (ops->cpu_boot)
106 		return ops->cpu_boot(cpu);
107 
108 	return -EOPNOTSUPP;
109 }
110 
111 static DECLARE_COMPLETION(cpu_running);
112 
__cpu_up(unsigned int cpu,struct task_struct * idle)113 int __cpu_up(unsigned int cpu, struct task_struct *idle)
114 {
115 	int ret;
116 	long status;
117 
118 	/*
119 	 * We need to tell the secondary core where to find its stack and the
120 	 * page tables.
121 	 */
122 	secondary_data.task = idle;
123 	update_cpu_boot_status(CPU_MMU_OFF);
124 
125 	/* Now bring the CPU into our world */
126 	ret = boot_secondary(cpu, idle);
127 	if (ret) {
128 		pr_err("CPU%u: failed to boot: %d\n", cpu, ret);
129 		return ret;
130 	}
131 
132 	/*
133 	 * CPU was successfully started, wait for it to come online or
134 	 * time out.
135 	 */
136 	wait_for_completion_timeout(&cpu_running,
137 				    msecs_to_jiffies(5000));
138 	if (cpu_online(cpu))
139 		return 0;
140 
141 	pr_crit("CPU%u: failed to come online\n", cpu);
142 	secondary_data.task = NULL;
143 	status = READ_ONCE(secondary_data.status);
144 	if (status == CPU_MMU_OFF)
145 		status = READ_ONCE(__early_cpu_boot_status);
146 
147 	switch (status & CPU_BOOT_STATUS_MASK) {
148 	default:
149 		pr_err("CPU%u: failed in unknown state : 0x%lx\n",
150 		       cpu, status);
151 		cpus_stuck_in_kernel++;
152 		break;
153 	case CPU_KILL_ME:
154 		if (!op_cpu_kill(cpu)) {
155 			pr_crit("CPU%u: died during early boot\n", cpu);
156 			break;
157 		}
158 		pr_crit("CPU%u: may not have shut down cleanly\n", cpu);
159 		fallthrough;
160 	case CPU_STUCK_IN_KERNEL:
161 		pr_crit("CPU%u: is stuck in kernel\n", cpu);
162 		if (status & CPU_STUCK_REASON_52_BIT_VA)
163 			pr_crit("CPU%u: does not support 52-bit VAs\n", cpu);
164 		if (status & CPU_STUCK_REASON_NO_GRAN) {
165 			pr_crit("CPU%u: does not support %luK granule\n",
166 				cpu, PAGE_SIZE / SZ_1K);
167 		}
168 		cpus_stuck_in_kernel++;
169 		break;
170 	case CPU_PANIC_KERNEL:
171 		panic("CPU%u detected unsupported configuration\n", cpu);
172 	}
173 
174 	return -EIO;
175 }
176 
init_gic_priority_masking(void)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 	WARN_ON(!(cpuflags & PSR_F_BIT));
188 
189 	gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
190 }
191 
192 /*
193  * This is the secondary CPU boot entry.  We're using this CPUs
194  * idle thread stack, but a set of temporary page tables.
195  */
secondary_start_kernel(void)196 asmlinkage notrace void secondary_start_kernel(void)
197 {
198 	u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
199 	struct mm_struct *mm = &init_mm;
200 	const struct cpu_operations *ops;
201 	unsigned int cpu = smp_processor_id();
202 
203 	/*
204 	 * All kernel threads share the same mm context; grab a
205 	 * reference and switch to it.
206 	 */
207 	mmgrab(mm);
208 	current->active_mm = mm;
209 
210 	/*
211 	 * TTBR0 is only used for the identity mapping at this stage. Make it
212 	 * point to zero page to avoid speculatively fetching new entries.
213 	 */
214 	cpu_uninstall_idmap();
215 
216 	if (system_uses_irq_prio_masking())
217 		init_gic_priority_masking();
218 
219 	rcu_cpu_starting(cpu);
220 	trace_hardirqs_off();
221 
222 	/*
223 	 * If the system has established the capabilities, make sure
224 	 * this CPU ticks all of those. If it doesn't, the CPU will
225 	 * fail to come online.
226 	 */
227 	check_local_cpu_capabilities();
228 
229 	ops = get_cpu_ops(cpu);
230 	if (ops->cpu_postboot)
231 		ops->cpu_postboot();
232 
233 	/*
234 	 * Log the CPU info before it is marked online and might get read.
235 	 */
236 	cpuinfo_store_cpu();
237 	store_cpu_topology(cpu);
238 
239 	/*
240 	 * Enable GIC and timers.
241 	 */
242 	notify_cpu_starting(cpu);
243 
244 	ipi_setup(cpu);
245 
246 	numa_add_cpu(cpu);
247 
248 	/*
249 	 * OK, now it's safe to let the boot CPU continue.  Wait for
250 	 * the CPU migration code to notice that the CPU is online
251 	 * before we continue.
252 	 */
253 	pr_info("CPU%u: Booted secondary processor 0x%010lx [0x%08x]\n",
254 					 cpu, (unsigned long)mpidr,
255 					 read_cpuid_id());
256 	update_cpu_boot_status(CPU_BOOT_SUCCESS);
257 	set_cpu_online(cpu, true);
258 	complete(&cpu_running);
259 
260 	local_daif_restore(DAIF_PROCCTX);
261 
262 	/*
263 	 * OK, it's off to the idle thread for us
264 	 */
265 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
266 }
267 
268 #ifdef CONFIG_HOTPLUG_CPU
op_cpu_disable(unsigned int cpu)269 static int op_cpu_disable(unsigned int cpu)
270 {
271 	const struct cpu_operations *ops = get_cpu_ops(cpu);
272 
273 	/*
274 	 * If we don't have a cpu_die method, abort before we reach the point
275 	 * of no return. CPU0 may not have an cpu_ops, so test for it.
276 	 */
277 	if (!ops || !ops->cpu_die)
278 		return -EOPNOTSUPP;
279 
280 	/*
281 	 * We may need to abort a hot unplug for some other mechanism-specific
282 	 * reason.
283 	 */
284 	if (ops->cpu_disable)
285 		return ops->cpu_disable(cpu);
286 
287 	return 0;
288 }
289 
290 /*
291  * __cpu_disable runs on the processor to be shutdown.
292  */
__cpu_disable(void)293 int __cpu_disable(void)
294 {
295 	unsigned int cpu = smp_processor_id();
296 	int ret;
297 
298 	ret = op_cpu_disable(cpu);
299 	if (ret)
300 		return ret;
301 
302 	remove_cpu_topology(cpu);
303 	numa_remove_cpu(cpu);
304 
305 	/*
306 	 * Take this CPU offline.  Once we clear this, we can't return,
307 	 * and we must not schedule until we're ready to give up the cpu.
308 	 */
309 	set_cpu_online(cpu, false);
310 	ipi_teardown(cpu);
311 
312 	/*
313 	 * OK - migrate IRQs away from this CPU
314 	 */
315 	irq_migrate_all_off_this_cpu();
316 
317 	return 0;
318 }
319 
op_cpu_kill(unsigned int cpu)320 static int op_cpu_kill(unsigned int cpu)
321 {
322 	const struct cpu_operations *ops = get_cpu_ops(cpu);
323 
324 	/*
325 	 * If we have no means of synchronising with the dying CPU, then assume
326 	 * that it is really dead. We can only wait for an arbitrary length of
327 	 * time and hope that it's dead, so let's skip the wait and just hope.
328 	 */
329 	if (!ops->cpu_kill)
330 		return 0;
331 
332 	return ops->cpu_kill(cpu);
333 }
334 
335 /*
336  * called on the thread which is asking for a CPU to be shutdown -
337  * waits until shutdown has completed, or it is timed out.
338  */
__cpu_die(unsigned int cpu)339 void __cpu_die(unsigned int cpu)
340 {
341 	int err;
342 
343 	if (!cpu_wait_death(cpu, 5)) {
344 		pr_crit("CPU%u: cpu didn't die\n", cpu);
345 		return;
346 	}
347 	pr_debug("CPU%u: shutdown\n", cpu);
348 
349 	/*
350 	 * Now that the dying CPU is beyond the point of no return w.r.t.
351 	 * in-kernel synchronisation, try to get the firwmare to help us to
352 	 * verify that it has really left the kernel before we consider
353 	 * clobbering anything it might still be using.
354 	 */
355 	err = op_cpu_kill(cpu);
356 	if (err)
357 		pr_warn("CPU%d may not have shut down cleanly: %d\n", cpu, err);
358 }
359 
360 /*
361  * Called from the idle thread for the CPU which has been shutdown.
362  *
363  */
cpu_die(void)364 void cpu_die(void)
365 {
366 	unsigned int cpu = smp_processor_id();
367 	const struct cpu_operations *ops = get_cpu_ops(cpu);
368 
369 	idle_task_exit();
370 
371 	local_daif_mask();
372 
373 	/* Tell __cpu_die() that this CPU is now safe to dispose of */
374 	(void)cpu_report_death();
375 
376 	/*
377 	 * Actually shutdown the CPU. This must never fail. The specific hotplug
378 	 * mechanism must perform all required cache maintenance to ensure that
379 	 * no dirty lines are lost in the process of shutting down the CPU.
380 	 */
381 	ops->cpu_die(cpu);
382 
383 	BUG();
384 }
385 #endif
386 
__cpu_try_die(int cpu)387 static void __cpu_try_die(int cpu)
388 {
389 #ifdef CONFIG_HOTPLUG_CPU
390 	const struct cpu_operations *ops = get_cpu_ops(cpu);
391 
392 	if (ops && ops->cpu_die)
393 		ops->cpu_die(cpu);
394 #endif
395 }
396 
397 /*
398  * Kill the calling secondary CPU, early in bringup before it is turned
399  * online.
400  */
cpu_die_early(void)401 void cpu_die_early(void)
402 {
403 	int cpu = smp_processor_id();
404 
405 	pr_crit("CPU%d: will not boot\n", cpu);
406 
407 	/* Mark this CPU absent */
408 	set_cpu_present(cpu, 0);
409 	rcu_report_dead(cpu);
410 
411 	if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
412 		update_cpu_boot_status(CPU_KILL_ME);
413 		__cpu_try_die(cpu);
414 	}
415 
416 	update_cpu_boot_status(CPU_STUCK_IN_KERNEL);
417 
418 	cpu_park_loop();
419 }
420 
hyp_mode_check(void)421 static void __init hyp_mode_check(void)
422 {
423 	if (is_hyp_mode_available())
424 		pr_info("CPU: All CPU(s) started at EL2\n");
425 	else if (is_hyp_mode_mismatched())
426 		WARN_TAINT(1, TAINT_CPU_OUT_OF_SPEC,
427 			   "CPU: CPUs started in inconsistent modes");
428 	else
429 		pr_info("CPU: All CPU(s) started at EL1\n");
430 	if (IS_ENABLED(CONFIG_KVM) && !is_kernel_in_hyp_mode()) {
431 		kvm_compute_layout();
432 		kvm_apply_hyp_relocations();
433 	}
434 }
435 
smp_cpus_done(unsigned int max_cpus)436 void __init smp_cpus_done(unsigned int max_cpus)
437 {
438 	pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
439 	setup_cpu_features();
440 	hyp_mode_check();
441 	apply_alternatives_all();
442 	mark_linear_text_alias_ro();
443 }
444 
smp_prepare_boot_cpu(void)445 void __init smp_prepare_boot_cpu(void)
446 {
447 	/*
448 	 * The runtime per-cpu areas have been allocated by
449 	 * setup_per_cpu_areas(), and CPU0's boot time per-cpu area will be
450 	 * freed shortly, so we must move over to the runtime per-cpu area.
451 	 */
452 	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
453 	cpuinfo_store_boot_cpu();
454 
455 	/*
456 	 * We now know enough about the boot CPU to apply the
457 	 * alternatives that cannot wait until interrupt handling
458 	 * and/or scheduling is enabled.
459 	 */
460 	apply_boot_alternatives();
461 
462 	/* Conditionally switch to GIC PMR for interrupt masking */
463 	if (system_uses_irq_prio_masking())
464 		init_gic_priority_masking();
465 
466 	kasan_init_hw_tags();
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  */
is_mpidr_duplicate(unsigned int cpu,u64 hwid)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  */
smp_cpu_setup(int cpu)489 static int __init smp_cpu_setup(int cpu)
490 {
491 	const struct cpu_operations *ops;
492 
493 	if (init_cpu_ops(cpu))
494 		return -ENODEV;
495 
496 	ops = get_cpu_ops(cpu);
497 	if (ops->cpu_init(cpu))
498 		return -ENODEV;
499 
500 	set_cpu_possible(cpu, true);
501 
502 	return 0;
503 }
504 
505 static bool bootcpu_valid __initdata;
506 static unsigned int cpu_count = 1;
507 
508 #ifdef CONFIG_ACPI
509 static struct acpi_madt_generic_interrupt cpu_madt_gicc[NR_CPUS];
510 
acpi_cpu_get_madt_gicc(int cpu)511 struct acpi_madt_generic_interrupt *acpi_cpu_get_madt_gicc(int cpu)
512 {
513 	return &cpu_madt_gicc[cpu];
514 }
515 EXPORT_SYMBOL_GPL(acpi_cpu_get_madt_gicc);
516 
517 /*
518  * acpi_map_gic_cpu_interface - parse processor MADT entry
519  *
520  * Carry out sanity checks on MADT processor entry and initialize
521  * cpu_logical_map on success
522  */
523 static void __init
acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt * processor)524 acpi_map_gic_cpu_interface(struct acpi_madt_generic_interrupt *processor)
525 {
526 	u64 hwid = processor->arm_mpidr;
527 
528 	if (!(processor->flags & ACPI_MADT_ENABLED)) {
529 		pr_debug("skipping disabled CPU entry with 0x%llx MPIDR\n", hwid);
530 		return;
531 	}
532 
533 	if (hwid & ~MPIDR_HWID_BITMASK || hwid == INVALID_HWID) {
534 		pr_err("skipping CPU entry with invalid MPIDR 0x%llx\n", hwid);
535 		return;
536 	}
537 
538 	if (is_mpidr_duplicate(cpu_count, hwid)) {
539 		pr_err("duplicate CPU MPIDR 0x%llx in MADT\n", hwid);
540 		return;
541 	}
542 
543 	/* Check if GICC structure of boot CPU is available in the MADT */
544 	if (cpu_logical_map(0) == hwid) {
545 		if (bootcpu_valid) {
546 			pr_err("duplicate boot CPU MPIDR: 0x%llx in MADT\n",
547 			       hwid);
548 			return;
549 		}
550 		bootcpu_valid = true;
551 		cpu_madt_gicc[0] = *processor;
552 		return;
553 	}
554 
555 	if (cpu_count >= NR_CPUS)
556 		return;
557 
558 	/* map the logical cpu id to cpu MPIDR */
559 	set_cpu_logical_map(cpu_count, hwid);
560 
561 	cpu_madt_gicc[cpu_count] = *processor;
562 
563 	/*
564 	 * Set-up the ACPI parking protocol cpu entries
565 	 * while initializing the cpu_logical_map to
566 	 * avoid parsing MADT entries multiple times for
567 	 * nothing (ie a valid cpu_logical_map entry should
568 	 * contain a valid parking protocol data set to
569 	 * initialize the cpu if the parking protocol is
570 	 * the only available enable method).
571 	 */
572 	acpi_set_mailbox_entry(cpu_count, processor);
573 
574 	cpu_count++;
575 }
576 
577 static int __init
acpi_parse_gic_cpu_interface(union acpi_subtable_headers * header,const unsigned long end)578 acpi_parse_gic_cpu_interface(union acpi_subtable_headers *header,
579 			     const unsigned long end)
580 {
581 	struct acpi_madt_generic_interrupt *processor;
582 
583 	processor = (struct acpi_madt_generic_interrupt *)header;
584 	if (BAD_MADT_GICC_ENTRY(processor, end))
585 		return -EINVAL;
586 
587 	acpi_table_print_madt_entry(&header->common);
588 
589 	acpi_map_gic_cpu_interface(processor);
590 
591 	return 0;
592 }
593 
acpi_parse_and_init_cpus(void)594 static void __init acpi_parse_and_init_cpus(void)
595 {
596 	int i;
597 
598 	/*
599 	 * do a walk of MADT to determine how many CPUs
600 	 * we have including disabled CPUs, and get information
601 	 * we need for SMP init.
602 	 */
603 	acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT,
604 				      acpi_parse_gic_cpu_interface, 0);
605 
606 	/*
607 	 * In ACPI, SMP and CPU NUMA information is provided in separate
608 	 * static tables, namely the MADT and the SRAT.
609 	 *
610 	 * Thus, it is simpler to first create the cpu logical map through
611 	 * an MADT walk and then map the logical cpus to their node ids
612 	 * as separate steps.
613 	 */
614 	acpi_map_cpus_to_nodes();
615 
616 	for (i = 0; i < nr_cpu_ids; i++)
617 		early_map_cpu_to_node(i, acpi_numa_get_nid(i));
618 }
619 #else
620 #define acpi_parse_and_init_cpus(...)	do { } while (0)
621 #endif
622 
623 /*
624  * Enumerate the possible CPU set from the device tree and build the
625  * cpu logical map array containing MPIDR values related to logical
626  * cpus. Assumes that cpu_logical_map(0) has already been initialized.
627  */
of_parse_and_init_cpus(void)628 static void __init of_parse_and_init_cpus(void)
629 {
630 	struct device_node *dn;
631 
632 	for_each_of_cpu_node(dn) {
633 		u64 hwid = of_get_cpu_hwid(dn, 0);
634 
635 		if (hwid & ~MPIDR_HWID_BITMASK)
636 			goto next;
637 
638 		if (is_mpidr_duplicate(cpu_count, hwid)) {
639 			pr_err("%pOF: duplicate cpu reg properties in the DT\n",
640 				dn);
641 			goto next;
642 		}
643 
644 		/*
645 		 * The numbering scheme requires that the boot CPU
646 		 * must be assigned logical id 0. Record it so that
647 		 * the logical map built from DT is validated and can
648 		 * be used.
649 		 */
650 		if (hwid == cpu_logical_map(0)) {
651 			if (bootcpu_valid) {
652 				pr_err("%pOF: duplicate boot cpu reg property in DT\n",
653 					dn);
654 				goto next;
655 			}
656 
657 			bootcpu_valid = true;
658 			early_map_cpu_to_node(0, of_node_to_nid(dn));
659 
660 			/*
661 			 * cpu_logical_map has already been
662 			 * initialized and the boot cpu doesn't need
663 			 * the enable-method so continue without
664 			 * incrementing cpu.
665 			 */
666 			continue;
667 		}
668 
669 		if (cpu_count >= NR_CPUS)
670 			goto next;
671 
672 		pr_debug("cpu logical map 0x%llx\n", hwid);
673 		set_cpu_logical_map(cpu_count, hwid);
674 
675 		early_map_cpu_to_node(cpu_count, of_node_to_nid(dn));
676 next:
677 		cpu_count++;
678 	}
679 }
680 
681 /*
682  * Enumerate the possible CPU set from the device tree or ACPI and build the
683  * cpu logical map array containing MPIDR values related to logical
684  * cpus. Assumes that cpu_logical_map(0) has already been initialized.
685  */
smp_init_cpus(void)686 void __init smp_init_cpus(void)
687 {
688 	int i;
689 
690 	if (acpi_disabled)
691 		of_parse_and_init_cpus();
692 	else
693 		acpi_parse_and_init_cpus();
694 
695 	if (cpu_count > nr_cpu_ids)
696 		pr_warn("Number of cores (%d) exceeds configured maximum of %u - clipping\n",
697 			cpu_count, nr_cpu_ids);
698 
699 	if (!bootcpu_valid) {
700 		pr_err("missing boot CPU MPIDR, not enabling secondaries\n");
701 		return;
702 	}
703 
704 	/*
705 	 * We need to set the cpu_logical_map entries before enabling
706 	 * the cpus so that cpu processor description entries (DT cpu nodes
707 	 * and ACPI MADT entries) can be retrieved by matching the cpu hwid
708 	 * with entries in cpu_logical_map while initializing the cpus.
709 	 * If the cpu set-up fails, invalidate the cpu_logical_map entry.
710 	 */
711 	for (i = 1; i < nr_cpu_ids; i++) {
712 		if (cpu_logical_map(i) != INVALID_HWID) {
713 			if (smp_cpu_setup(i))
714 				set_cpu_logical_map(i, INVALID_HWID);
715 		}
716 	}
717 }
718 
smp_prepare_cpus(unsigned int max_cpus)719 void __init smp_prepare_cpus(unsigned int max_cpus)
720 {
721 	const struct cpu_operations *ops;
722 	int err;
723 	unsigned int cpu;
724 	unsigned int this_cpu;
725 
726 	init_cpu_topology();
727 
728 	this_cpu = smp_processor_id();
729 	store_cpu_topology(this_cpu);
730 	numa_store_cpu_info(this_cpu);
731 	numa_add_cpu(this_cpu);
732 
733 	/*
734 	 * If UP is mandated by "nosmp" (which implies "maxcpus=0"), don't set
735 	 * secondary CPUs present.
736 	 */
737 	if (max_cpus == 0)
738 		return;
739 
740 	/*
741 	 * Initialise the present map (which describes the set of CPUs
742 	 * actually populated at the present time) and release the
743 	 * secondaries from the bootloader.
744 	 */
745 	for_each_possible_cpu(cpu) {
746 
747 		per_cpu(cpu_number, cpu) = cpu;
748 
749 		if (cpu == smp_processor_id())
750 			continue;
751 
752 		ops = get_cpu_ops(cpu);
753 		if (!ops)
754 			continue;
755 
756 		err = ops->cpu_prepare(cpu);
757 		if (err)
758 			continue;
759 
760 		set_cpu_present(cpu, true);
761 		numa_store_cpu_info(cpu);
762 	}
763 }
764 
765 static const char *ipi_types[NR_IPI] __tracepoint_string = {
766 	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
767 	[IPI_CALL_FUNC]		= "Function call interrupts",
768 	[IPI_CPU_STOP]		= "CPU stop interrupts",
769 	[IPI_CPU_CRASH_STOP]	= "CPU stop (for crash dump) interrupts",
770 	[IPI_TIMER]		= "Timer broadcast interrupts",
771 	[IPI_IRQ_WORK]		= "IRQ work interrupts",
772 	[IPI_WAKEUP]		= "CPU wake-up interrupts",
773 };
774 
775 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
776 
777 unsigned long irq_err_count;
778 
arch_show_interrupts(struct seq_file * p,int prec)779 int arch_show_interrupts(struct seq_file *p, int prec)
780 {
781 	unsigned int cpu, i;
782 
783 	for (i = 0; i < NR_IPI; i++) {
784 		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
785 			   prec >= 4 ? " " : "");
786 		for_each_online_cpu(cpu)
787 			seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu));
788 		seq_printf(p, "      %s\n", ipi_types[i]);
789 	}
790 
791 	seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
792 	return 0;
793 }
794 
arch_send_call_function_ipi_mask(const struct cpumask * mask)795 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
796 {
797 	smp_cross_call(mask, IPI_CALL_FUNC);
798 }
799 
arch_send_call_function_single_ipi(int cpu)800 void arch_send_call_function_single_ipi(int cpu)
801 {
802 	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC);
803 }
804 
805 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
arch_send_wakeup_ipi_mask(const struct cpumask * mask)806 void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
807 {
808 	smp_cross_call(mask, IPI_WAKEUP);
809 }
810 #endif
811 
812 #ifdef CONFIG_IRQ_WORK
arch_irq_work_raise(void)813 void arch_irq_work_raise(void)
814 {
815 	smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
816 }
817 #endif
818 
local_cpu_stop(void)819 static void local_cpu_stop(void)
820 {
821 	set_cpu_online(smp_processor_id(), false);
822 
823 	local_daif_mask();
824 	sdei_mask_local_cpu();
825 	cpu_park_loop();
826 }
827 
828 /*
829  * We need to implement panic_smp_self_stop() for parallel panic() calls, so
830  * that cpu_online_mask gets correctly updated and smp_send_stop() can skip
831  * CPUs that have already stopped themselves.
832  */
panic_smp_self_stop(void)833 void panic_smp_self_stop(void)
834 {
835 	local_cpu_stop();
836 }
837 
838 #ifdef CONFIG_KEXEC_CORE
839 static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
840 #endif
841 
ipi_cpu_crash_stop(unsigned int cpu,struct pt_regs * regs)842 static void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
843 {
844 #ifdef CONFIG_KEXEC_CORE
845 	crash_save_cpu(regs, cpu);
846 
847 	atomic_dec(&waiting_for_crash_ipi);
848 
849 	local_irq_disable();
850 	sdei_mask_local_cpu();
851 
852 	if (IS_ENABLED(CONFIG_HOTPLUG_CPU))
853 		__cpu_try_die(cpu);
854 
855 	/* just in case */
856 	cpu_park_loop();
857 #endif
858 }
859 
860 /*
861  * Main handler for inter-processor interrupts
862  */
do_handle_IPI(int ipinr)863 static void do_handle_IPI(int ipinr)
864 {
865 	unsigned int cpu = smp_processor_id();
866 
867 	if ((unsigned)ipinr < NR_IPI)
868 		trace_ipi_entry_rcuidle(ipi_types[ipinr]);
869 
870 	switch (ipinr) {
871 	case IPI_RESCHEDULE:
872 		scheduler_ipi();
873 		break;
874 
875 	case IPI_CALL_FUNC:
876 		generic_smp_call_function_interrupt();
877 		break;
878 
879 	case IPI_CPU_STOP:
880 		local_cpu_stop();
881 		break;
882 
883 	case IPI_CPU_CRASH_STOP:
884 		if (IS_ENABLED(CONFIG_KEXEC_CORE)) {
885 			ipi_cpu_crash_stop(cpu, get_irq_regs());
886 
887 			unreachable();
888 		}
889 		break;
890 
891 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
892 	case IPI_TIMER:
893 		tick_receive_broadcast();
894 		break;
895 #endif
896 
897 #ifdef CONFIG_IRQ_WORK
898 	case IPI_IRQ_WORK:
899 		irq_work_run();
900 		break;
901 #endif
902 
903 #ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL
904 	case IPI_WAKEUP:
905 		WARN_ONCE(!acpi_parking_protocol_valid(cpu),
906 			  "CPU%u: Wake-up IPI outside the ACPI parking protocol\n",
907 			  cpu);
908 		break;
909 #endif
910 
911 	default:
912 		pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr);
913 		break;
914 	}
915 
916 	if ((unsigned)ipinr < NR_IPI)
917 		trace_ipi_exit_rcuidle(ipi_types[ipinr]);
918 }
919 
ipi_handler(int irq,void * data)920 static irqreturn_t ipi_handler(int irq, void *data)
921 {
922 	do_handle_IPI(irq - ipi_irq_base);
923 	return IRQ_HANDLED;
924 }
925 
smp_cross_call(const struct cpumask * target,unsigned int ipinr)926 static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
927 {
928 	trace_ipi_raise(target, ipi_types[ipinr]);
929 	__ipi_send_mask(ipi_desc[ipinr], target);
930 }
931 
ipi_setup(int cpu)932 static void ipi_setup(int cpu)
933 {
934 	int i;
935 
936 	if (WARN_ON_ONCE(!ipi_irq_base))
937 		return;
938 
939 	for (i = 0; i < nr_ipi; i++)
940 		enable_percpu_irq(ipi_irq_base + i, 0);
941 }
942 
943 #ifdef CONFIG_HOTPLUG_CPU
ipi_teardown(int cpu)944 static void ipi_teardown(int cpu)
945 {
946 	int i;
947 
948 	if (WARN_ON_ONCE(!ipi_irq_base))
949 		return;
950 
951 	for (i = 0; i < nr_ipi; i++)
952 		disable_percpu_irq(ipi_irq_base + i);
953 }
954 #endif
955 
set_smp_ipi_range(int ipi_base,int n)956 void __init set_smp_ipi_range(int ipi_base, int n)
957 {
958 	int i;
959 
960 	WARN_ON(n < NR_IPI);
961 	nr_ipi = min(n, NR_IPI);
962 
963 	for (i = 0; i < nr_ipi; i++) {
964 		int err;
965 
966 		err = request_percpu_irq(ipi_base + i, ipi_handler,
967 					 "IPI", &cpu_number);
968 		WARN_ON(err);
969 
970 		ipi_desc[i] = irq_to_desc(ipi_base + i);
971 		irq_set_status_flags(ipi_base + i, IRQ_HIDDEN);
972 	}
973 
974 	ipi_irq_base = ipi_base;
975 
976 	/* Setup the boot CPU immediately */
977 	ipi_setup(smp_processor_id());
978 }
979 
smp_send_reschedule(int cpu)980 void smp_send_reschedule(int cpu)
981 {
982 	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
983 }
984 
985 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
tick_broadcast(const struct cpumask * mask)986 void tick_broadcast(const struct cpumask *mask)
987 {
988 	smp_cross_call(mask, IPI_TIMER);
989 }
990 #endif
991 
992 /*
993  * The number of CPUs online, not counting this CPU (which may not be
994  * fully online and so not counted in num_online_cpus()).
995  */
num_other_online_cpus(void)996 static inline unsigned int num_other_online_cpus(void)
997 {
998 	unsigned int this_cpu_online = cpu_online(smp_processor_id());
999 
1000 	return num_online_cpus() - this_cpu_online;
1001 }
1002 
smp_send_stop(void)1003 void smp_send_stop(void)
1004 {
1005 	unsigned long timeout;
1006 
1007 	if (num_other_online_cpus()) {
1008 		cpumask_t mask;
1009 
1010 		cpumask_copy(&mask, cpu_online_mask);
1011 		cpumask_clear_cpu(smp_processor_id(), &mask);
1012 
1013 		if (system_state <= SYSTEM_RUNNING)
1014 			pr_crit("SMP: stopping secondary CPUs\n");
1015 		smp_cross_call(&mask, IPI_CPU_STOP);
1016 	}
1017 
1018 	/* Wait up to one second for other CPUs to stop */
1019 	timeout = USEC_PER_SEC;
1020 	while (num_other_online_cpus() && timeout--)
1021 		udelay(1);
1022 
1023 	if (num_other_online_cpus())
1024 		pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
1025 			cpumask_pr_args(cpu_online_mask));
1026 
1027 	sdei_mask_local_cpu();
1028 }
1029 
1030 #ifdef CONFIG_KEXEC_CORE
crash_smp_send_stop(void)1031 void crash_smp_send_stop(void)
1032 {
1033 	static int cpus_stopped;
1034 	cpumask_t mask;
1035 	unsigned long timeout;
1036 
1037 	/*
1038 	 * This function can be called twice in panic path, but obviously
1039 	 * we execute this only once.
1040 	 */
1041 	if (cpus_stopped)
1042 		return;
1043 
1044 	cpus_stopped = 1;
1045 
1046 	/*
1047 	 * If this cpu is the only one alive at this point in time, online or
1048 	 * not, there are no stop messages to be sent around, so just back out.
1049 	 */
1050 	if (num_other_online_cpus() == 0) {
1051 		sdei_mask_local_cpu();
1052 		return;
1053 	}
1054 
1055 	cpumask_copy(&mask, cpu_online_mask);
1056 	cpumask_clear_cpu(smp_processor_id(), &mask);
1057 
1058 	atomic_set(&waiting_for_crash_ipi, num_other_online_cpus());
1059 
1060 	pr_crit("SMP: stopping secondary CPUs\n");
1061 	smp_cross_call(&mask, IPI_CPU_CRASH_STOP);
1062 
1063 	/* Wait up to one second for other CPUs to stop */
1064 	timeout = USEC_PER_SEC;
1065 	while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--)
1066 		udelay(1);
1067 
1068 	if (atomic_read(&waiting_for_crash_ipi) > 0)
1069 		pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
1070 			cpumask_pr_args(&mask));
1071 
1072 	sdei_mask_local_cpu();
1073 }
1074 
smp_crash_stop_failed(void)1075 bool smp_crash_stop_failed(void)
1076 {
1077 	return (atomic_read(&waiting_for_crash_ipi) > 0);
1078 }
1079 #endif
1080 
have_cpu_die(void)1081 static bool have_cpu_die(void)
1082 {
1083 #ifdef CONFIG_HOTPLUG_CPU
1084 	int any_cpu = raw_smp_processor_id();
1085 	const struct cpu_operations *ops = get_cpu_ops(any_cpu);
1086 
1087 	if (ops && ops->cpu_die)
1088 		return true;
1089 #endif
1090 	return false;
1091 }
1092 
cpus_are_stuck_in_kernel(void)1093 bool cpus_are_stuck_in_kernel(void)
1094 {
1095 	bool smp_spin_tables = (num_possible_cpus() > 1 && !have_cpu_die());
1096 
1097 	return !!cpus_stuck_in_kernel || smp_spin_tables ||
1098 		is_protected_kvm_enabled();
1099 }
1100