xref: /linux/drivers/base/arch_topology.c (revision 7255fcc80d4b525cc10cfaaf7f485830d4ed2000)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Arch specific cpu topology information
4  *
5  * Copyright (C) 2016, ARM Ltd.
6  * Written by: Juri Lelli, ARM Ltd.
7  */
8 
9 #include <linux/acpi.h>
10 #include <linux/cacheinfo.h>
11 #include <linux/cpu.h>
12 #include <linux/cpufreq.h>
13 #include <linux/device.h>
14 #include <linux/of.h>
15 #include <linux/slab.h>
16 #include <linux/sched/topology.h>
17 #include <linux/cpuset.h>
18 #include <linux/cpumask.h>
19 #include <linux/init.h>
20 #include <linux/rcupdate.h>
21 #include <linux/sched.h>
22 #include <linux/units.h>
23 
24 #define CREATE_TRACE_POINTS
25 #include <trace/events/thermal_pressure.h>
26 
27 static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data);
28 static struct cpumask scale_freq_counters_mask;
29 static bool scale_freq_invariant;
30 DEFINE_PER_CPU(unsigned long, capacity_freq_ref) = 1;
31 EXPORT_PER_CPU_SYMBOL_GPL(capacity_freq_ref);
32 
33 static bool supports_scale_freq_counters(const struct cpumask *cpus)
34 {
35 	return cpumask_subset(cpus, &scale_freq_counters_mask);
36 }
37 
38 bool topology_scale_freq_invariant(void)
39 {
40 	return cpufreq_supports_freq_invariance() ||
41 	       supports_scale_freq_counters(cpu_online_mask);
42 }
43 
44 static void update_scale_freq_invariant(bool status)
45 {
46 	if (scale_freq_invariant == status)
47 		return;
48 
49 	/*
50 	 * Task scheduler behavior depends on frequency invariance support,
51 	 * either cpufreq or counter driven. If the support status changes as
52 	 * a result of counter initialisation and use, retrigger the build of
53 	 * scheduling domains to ensure the information is propagated properly.
54 	 */
55 	if (topology_scale_freq_invariant() == status) {
56 		scale_freq_invariant = status;
57 		rebuild_sched_domains_energy();
58 	}
59 }
60 
61 void topology_set_scale_freq_source(struct scale_freq_data *data,
62 				    const struct cpumask *cpus)
63 {
64 	struct scale_freq_data *sfd;
65 	int cpu;
66 
67 	/*
68 	 * Avoid calling rebuild_sched_domains() unnecessarily if FIE is
69 	 * supported by cpufreq.
70 	 */
71 	if (cpumask_empty(&scale_freq_counters_mask))
72 		scale_freq_invariant = topology_scale_freq_invariant();
73 
74 	rcu_read_lock();
75 
76 	for_each_cpu(cpu, cpus) {
77 		sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));
78 
79 		/* Use ARCH provided counters whenever possible */
80 		if (!sfd || sfd->source != SCALE_FREQ_SOURCE_ARCH) {
81 			rcu_assign_pointer(per_cpu(sft_data, cpu), data);
82 			cpumask_set_cpu(cpu, &scale_freq_counters_mask);
83 		}
84 	}
85 
86 	rcu_read_unlock();
87 
88 	update_scale_freq_invariant(true);
89 }
90 EXPORT_SYMBOL_GPL(topology_set_scale_freq_source);
91 
92 void topology_clear_scale_freq_source(enum scale_freq_source source,
93 				      const struct cpumask *cpus)
94 {
95 	struct scale_freq_data *sfd;
96 	int cpu;
97 
98 	rcu_read_lock();
99 
100 	for_each_cpu(cpu, cpus) {
101 		sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));
102 
103 		if (sfd && sfd->source == source) {
104 			rcu_assign_pointer(per_cpu(sft_data, cpu), NULL);
105 			cpumask_clear_cpu(cpu, &scale_freq_counters_mask);
106 		}
107 	}
108 
109 	rcu_read_unlock();
110 
111 	/*
112 	 * Make sure all references to previous sft_data are dropped to avoid
113 	 * use-after-free races.
114 	 */
115 	synchronize_rcu();
116 
117 	update_scale_freq_invariant(false);
118 }
119 EXPORT_SYMBOL_GPL(topology_clear_scale_freq_source);
120 
121 void topology_scale_freq_tick(void)
122 {
123 	struct scale_freq_data *sfd = rcu_dereference_sched(*this_cpu_ptr(&sft_data));
124 
125 	if (sfd)
126 		sfd->set_freq_scale();
127 }
128 
129 DEFINE_PER_CPU(unsigned long, arch_freq_scale) = SCHED_CAPACITY_SCALE;
130 EXPORT_PER_CPU_SYMBOL_GPL(arch_freq_scale);
131 
132 void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
133 			     unsigned long max_freq)
134 {
135 	unsigned long scale;
136 	int i;
137 
138 	if (WARN_ON_ONCE(!cur_freq || !max_freq))
139 		return;
140 
141 	/*
142 	 * If the use of counters for FIE is enabled, just return as we don't
143 	 * want to update the scale factor with information from CPUFREQ.
144 	 * Instead the scale factor will be updated from arch_scale_freq_tick.
145 	 */
146 	if (supports_scale_freq_counters(cpus))
147 		return;
148 
149 	scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
150 
151 	for_each_cpu(i, cpus)
152 		per_cpu(arch_freq_scale, i) = scale;
153 }
154 
155 DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
156 EXPORT_PER_CPU_SYMBOL_GPL(cpu_scale);
157 
158 void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
159 {
160 	per_cpu(cpu_scale, cpu) = capacity;
161 }
162 
163 DEFINE_PER_CPU(unsigned long, thermal_pressure);
164 
165 /**
166  * topology_update_thermal_pressure() - Update thermal pressure for CPUs
167  * @cpus        : The related CPUs for which capacity has been reduced
168  * @capped_freq : The maximum allowed frequency that CPUs can run at
169  *
170  * Update the value of thermal pressure for all @cpus in the mask. The
171  * cpumask should include all (online+offline) affected CPUs, to avoid
172  * operating on stale data when hot-plug is used for some CPUs. The
173  * @capped_freq reflects the currently allowed max CPUs frequency due to
174  * thermal capping. It might be also a boost frequency value, which is bigger
175  * than the internal 'capacity_freq_ref' max frequency. In such case the
176  * pressure value should simply be removed, since this is an indication that
177  * there is no thermal throttling. The @capped_freq must be provided in kHz.
178  */
179 void topology_update_thermal_pressure(const struct cpumask *cpus,
180 				      unsigned long capped_freq)
181 {
182 	unsigned long max_capacity, capacity, th_pressure;
183 	u32 max_freq;
184 	int cpu;
185 
186 	cpu = cpumask_first(cpus);
187 	max_capacity = arch_scale_cpu_capacity(cpu);
188 	max_freq = arch_scale_freq_ref(cpu);
189 
190 	/*
191 	 * Handle properly the boost frequencies, which should simply clean
192 	 * the thermal pressure value.
193 	 */
194 	if (max_freq <= capped_freq)
195 		capacity = max_capacity;
196 	else
197 		capacity = mult_frac(max_capacity, capped_freq, max_freq);
198 
199 	th_pressure = max_capacity - capacity;
200 
201 	trace_thermal_pressure_update(cpu, th_pressure);
202 
203 	for_each_cpu(cpu, cpus)
204 		WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
205 }
206 EXPORT_SYMBOL_GPL(topology_update_thermal_pressure);
207 
208 static ssize_t cpu_capacity_show(struct device *dev,
209 				 struct device_attribute *attr,
210 				 char *buf)
211 {
212 	struct cpu *cpu = container_of(dev, struct cpu, dev);
213 
214 	return sysfs_emit(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id));
215 }
216 
217 static void update_topology_flags_workfn(struct work_struct *work);
218 static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);
219 
220 static DEVICE_ATTR_RO(cpu_capacity);
221 
222 static int cpu_capacity_sysctl_add(unsigned int cpu)
223 {
224 	struct device *cpu_dev = get_cpu_device(cpu);
225 
226 	if (!cpu_dev)
227 		return -ENOENT;
228 
229 	device_create_file(cpu_dev, &dev_attr_cpu_capacity);
230 
231 	return 0;
232 }
233 
234 static int cpu_capacity_sysctl_remove(unsigned int cpu)
235 {
236 	struct device *cpu_dev = get_cpu_device(cpu);
237 
238 	if (!cpu_dev)
239 		return -ENOENT;
240 
241 	device_remove_file(cpu_dev, &dev_attr_cpu_capacity);
242 
243 	return 0;
244 }
245 
246 static int register_cpu_capacity_sysctl(void)
247 {
248 	cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "topology/cpu-capacity",
249 			  cpu_capacity_sysctl_add, cpu_capacity_sysctl_remove);
250 
251 	return 0;
252 }
253 subsys_initcall(register_cpu_capacity_sysctl);
254 
255 static int update_topology;
256 
257 int topology_update_cpu_topology(void)
258 {
259 	return update_topology;
260 }
261 
262 /*
263  * Updating the sched_domains can't be done directly from cpufreq callbacks
264  * due to locking, so queue the work for later.
265  */
266 static void update_topology_flags_workfn(struct work_struct *work)
267 {
268 	update_topology = 1;
269 	rebuild_sched_domains();
270 	pr_debug("sched_domain hierarchy rebuilt, flags updated\n");
271 	update_topology = 0;
272 }
273 
274 static u32 *raw_capacity;
275 
276 static int free_raw_capacity(void)
277 {
278 	kfree(raw_capacity);
279 	raw_capacity = NULL;
280 
281 	return 0;
282 }
283 
284 void topology_normalize_cpu_scale(void)
285 {
286 	u64 capacity;
287 	u64 capacity_scale;
288 	int cpu;
289 
290 	if (!raw_capacity)
291 		return;
292 
293 	capacity_scale = 1;
294 	for_each_possible_cpu(cpu) {
295 		capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu);
296 		capacity_scale = max(capacity, capacity_scale);
297 	}
298 
299 	pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale);
300 	for_each_possible_cpu(cpu) {
301 		capacity = raw_capacity[cpu] * per_cpu(capacity_freq_ref, cpu);
302 		capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
303 			capacity_scale);
304 		topology_set_cpu_scale(cpu, capacity);
305 		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
306 			cpu, topology_get_cpu_scale(cpu));
307 	}
308 }
309 
310 bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
311 {
312 	struct clk *cpu_clk;
313 	static bool cap_parsing_failed;
314 	int ret;
315 	u32 cpu_capacity;
316 
317 	if (cap_parsing_failed)
318 		return false;
319 
320 	ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
321 				   &cpu_capacity);
322 	if (!ret) {
323 		if (!raw_capacity) {
324 			raw_capacity = kcalloc(num_possible_cpus(),
325 					       sizeof(*raw_capacity),
326 					       GFP_KERNEL);
327 			if (!raw_capacity) {
328 				cap_parsing_failed = true;
329 				return false;
330 			}
331 		}
332 		raw_capacity[cpu] = cpu_capacity;
333 		pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
334 			cpu_node, raw_capacity[cpu]);
335 
336 		/*
337 		 * Update capacity_freq_ref for calculating early boot CPU capacities.
338 		 * For non-clk CPU DVFS mechanism, there's no way to get the
339 		 * frequency value now, assuming they are running at the same
340 		 * frequency (by keeping the initial capacity_freq_ref value).
341 		 */
342 		cpu_clk = of_clk_get(cpu_node, 0);
343 		if (!PTR_ERR_OR_ZERO(cpu_clk)) {
344 			per_cpu(capacity_freq_ref, cpu) =
345 				clk_get_rate(cpu_clk) / HZ_PER_KHZ;
346 			clk_put(cpu_clk);
347 		}
348 	} else {
349 		if (raw_capacity) {
350 			pr_err("cpu_capacity: missing %pOF raw capacity\n",
351 				cpu_node);
352 			pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
353 		}
354 		cap_parsing_failed = true;
355 		free_raw_capacity();
356 	}
357 
358 	return !ret;
359 }
360 
361 void __weak freq_inv_set_max_ratio(int cpu, u64 max_rate)
362 {
363 }
364 
365 #ifdef CONFIG_ACPI_CPPC_LIB
366 #include <acpi/cppc_acpi.h>
367 
368 void topology_init_cpu_capacity_cppc(void)
369 {
370 	u64 capacity, capacity_scale = 0;
371 	struct cppc_perf_caps perf_caps;
372 	int cpu;
373 
374 	if (likely(!acpi_cpc_valid()))
375 		return;
376 
377 	raw_capacity = kcalloc(num_possible_cpus(), sizeof(*raw_capacity),
378 			       GFP_KERNEL);
379 	if (!raw_capacity)
380 		return;
381 
382 	for_each_possible_cpu(cpu) {
383 		if (!cppc_get_perf_caps(cpu, &perf_caps) &&
384 		    (perf_caps.highest_perf >= perf_caps.nominal_perf) &&
385 		    (perf_caps.highest_perf >= perf_caps.lowest_perf)) {
386 			raw_capacity[cpu] = perf_caps.highest_perf;
387 			capacity_scale = max_t(u64, capacity_scale, raw_capacity[cpu]);
388 
389 			per_cpu(capacity_freq_ref, cpu) = cppc_perf_to_khz(&perf_caps, raw_capacity[cpu]);
390 
391 			pr_debug("cpu_capacity: CPU%d cpu_capacity=%u (raw).\n",
392 				 cpu, raw_capacity[cpu]);
393 			continue;
394 		}
395 
396 		pr_err("cpu_capacity: CPU%d missing/invalid highest performance.\n", cpu);
397 		pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
398 		goto exit;
399 	}
400 
401 	for_each_possible_cpu(cpu) {
402 		freq_inv_set_max_ratio(cpu,
403 				       per_cpu(capacity_freq_ref, cpu) * HZ_PER_KHZ);
404 
405 		capacity = raw_capacity[cpu];
406 		capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
407 				     capacity_scale);
408 		topology_set_cpu_scale(cpu, capacity);
409 		pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
410 			cpu, topology_get_cpu_scale(cpu));
411 	}
412 
413 	schedule_work(&update_topology_flags_work);
414 	pr_debug("cpu_capacity: cpu_capacity initialization done\n");
415 
416 exit:
417 	free_raw_capacity();
418 }
419 #endif
420 
421 #ifdef CONFIG_CPU_FREQ
422 static cpumask_var_t cpus_to_visit;
423 static void parsing_done_workfn(struct work_struct *work);
424 static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
425 
426 static int
427 init_cpu_capacity_callback(struct notifier_block *nb,
428 			   unsigned long val,
429 			   void *data)
430 {
431 	struct cpufreq_policy *policy = data;
432 	int cpu;
433 
434 	if (val != CPUFREQ_CREATE_POLICY)
435 		return 0;
436 
437 	pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
438 		 cpumask_pr_args(policy->related_cpus),
439 		 cpumask_pr_args(cpus_to_visit));
440 
441 	cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
442 
443 	for_each_cpu(cpu, policy->related_cpus) {
444 		per_cpu(capacity_freq_ref, cpu) = policy->cpuinfo.max_freq;
445 		freq_inv_set_max_ratio(cpu,
446 				       per_cpu(capacity_freq_ref, cpu) * HZ_PER_KHZ);
447 	}
448 
449 	if (cpumask_empty(cpus_to_visit)) {
450 		if (raw_capacity) {
451 			topology_normalize_cpu_scale();
452 			schedule_work(&update_topology_flags_work);
453 			free_raw_capacity();
454 		}
455 		pr_debug("cpu_capacity: parsing done\n");
456 		schedule_work(&parsing_done_work);
457 	}
458 
459 	return 0;
460 }
461 
462 static struct notifier_block init_cpu_capacity_notifier = {
463 	.notifier_call = init_cpu_capacity_callback,
464 };
465 
466 static int __init register_cpufreq_notifier(void)
467 {
468 	int ret;
469 
470 	/*
471 	 * On ACPI-based systems skip registering cpufreq notifier as cpufreq
472 	 * information is not needed for cpu capacity initialization.
473 	 */
474 	if (!acpi_disabled)
475 		return -EINVAL;
476 
477 	if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL))
478 		return -ENOMEM;
479 
480 	cpumask_copy(cpus_to_visit, cpu_possible_mask);
481 
482 	ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
483 					CPUFREQ_POLICY_NOTIFIER);
484 
485 	if (ret)
486 		free_cpumask_var(cpus_to_visit);
487 
488 	return ret;
489 }
490 core_initcall(register_cpufreq_notifier);
491 
492 static void parsing_done_workfn(struct work_struct *work)
493 {
494 	cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
495 					 CPUFREQ_POLICY_NOTIFIER);
496 	free_cpumask_var(cpus_to_visit);
497 }
498 
499 #else
500 core_initcall(free_raw_capacity);
501 #endif
502 
503 #if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
504 /*
505  * This function returns the logic cpu number of the node.
506  * There are basically three kinds of return values:
507  * (1) logic cpu number which is > 0.
508  * (2) -ENODEV when the device tree(DT) node is valid and found in the DT but
509  * there is no possible logical CPU in the kernel to match. This happens
510  * when CONFIG_NR_CPUS is configure to be smaller than the number of
511  * CPU nodes in DT. We need to just ignore this case.
512  * (3) -1 if the node does not exist in the device tree
513  */
514 static int __init get_cpu_for_node(struct device_node *node)
515 {
516 	struct device_node *cpu_node;
517 	int cpu;
518 
519 	cpu_node = of_parse_phandle(node, "cpu", 0);
520 	if (!cpu_node)
521 		return -1;
522 
523 	cpu = of_cpu_node_to_id(cpu_node);
524 	if (cpu >= 0)
525 		topology_parse_cpu_capacity(cpu_node, cpu);
526 	else
527 		pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n",
528 			cpu_node, cpumask_pr_args(cpu_possible_mask));
529 
530 	of_node_put(cpu_node);
531 	return cpu;
532 }
533 
534 static int __init parse_core(struct device_node *core, int package_id,
535 			     int cluster_id, int core_id)
536 {
537 	char name[20];
538 	bool leaf = true;
539 	int i = 0;
540 	int cpu;
541 	struct device_node *t;
542 
543 	do {
544 		snprintf(name, sizeof(name), "thread%d", i);
545 		t = of_get_child_by_name(core, name);
546 		if (t) {
547 			leaf = false;
548 			cpu = get_cpu_for_node(t);
549 			if (cpu >= 0) {
550 				cpu_topology[cpu].package_id = package_id;
551 				cpu_topology[cpu].cluster_id = cluster_id;
552 				cpu_topology[cpu].core_id = core_id;
553 				cpu_topology[cpu].thread_id = i;
554 			} else if (cpu != -ENODEV) {
555 				pr_err("%pOF: Can't get CPU for thread\n", t);
556 				of_node_put(t);
557 				return -EINVAL;
558 			}
559 			of_node_put(t);
560 		}
561 		i++;
562 	} while (t);
563 
564 	cpu = get_cpu_for_node(core);
565 	if (cpu >= 0) {
566 		if (!leaf) {
567 			pr_err("%pOF: Core has both threads and CPU\n",
568 			       core);
569 			return -EINVAL;
570 		}
571 
572 		cpu_topology[cpu].package_id = package_id;
573 		cpu_topology[cpu].cluster_id = cluster_id;
574 		cpu_topology[cpu].core_id = core_id;
575 	} else if (leaf && cpu != -ENODEV) {
576 		pr_err("%pOF: Can't get CPU for leaf core\n", core);
577 		return -EINVAL;
578 	}
579 
580 	return 0;
581 }
582 
583 static int __init parse_cluster(struct device_node *cluster, int package_id,
584 				int cluster_id, int depth)
585 {
586 	char name[20];
587 	bool leaf = true;
588 	bool has_cores = false;
589 	struct device_node *c;
590 	int core_id = 0;
591 	int i, ret;
592 
593 	/*
594 	 * First check for child clusters; we currently ignore any
595 	 * information about the nesting of clusters and present the
596 	 * scheduler with a flat list of them.
597 	 */
598 	i = 0;
599 	do {
600 		snprintf(name, sizeof(name), "cluster%d", i);
601 		c = of_get_child_by_name(cluster, name);
602 		if (c) {
603 			leaf = false;
604 			ret = parse_cluster(c, package_id, i, depth + 1);
605 			if (depth > 0)
606 				pr_warn("Topology for clusters of clusters not yet supported\n");
607 			of_node_put(c);
608 			if (ret != 0)
609 				return ret;
610 		}
611 		i++;
612 	} while (c);
613 
614 	/* Now check for cores */
615 	i = 0;
616 	do {
617 		snprintf(name, sizeof(name), "core%d", i);
618 		c = of_get_child_by_name(cluster, name);
619 		if (c) {
620 			has_cores = true;
621 
622 			if (depth == 0) {
623 				pr_err("%pOF: cpu-map children should be clusters\n",
624 				       c);
625 				of_node_put(c);
626 				return -EINVAL;
627 			}
628 
629 			if (leaf) {
630 				ret = parse_core(c, package_id, cluster_id,
631 						 core_id++);
632 			} else {
633 				pr_err("%pOF: Non-leaf cluster with core %s\n",
634 				       cluster, name);
635 				ret = -EINVAL;
636 			}
637 
638 			of_node_put(c);
639 			if (ret != 0)
640 				return ret;
641 		}
642 		i++;
643 	} while (c);
644 
645 	if (leaf && !has_cores)
646 		pr_warn("%pOF: empty cluster\n", cluster);
647 
648 	return 0;
649 }
650 
651 static int __init parse_socket(struct device_node *socket)
652 {
653 	char name[20];
654 	struct device_node *c;
655 	bool has_socket = false;
656 	int package_id = 0, ret;
657 
658 	do {
659 		snprintf(name, sizeof(name), "socket%d", package_id);
660 		c = of_get_child_by_name(socket, name);
661 		if (c) {
662 			has_socket = true;
663 			ret = parse_cluster(c, package_id, -1, 0);
664 			of_node_put(c);
665 			if (ret != 0)
666 				return ret;
667 		}
668 		package_id++;
669 	} while (c);
670 
671 	if (!has_socket)
672 		ret = parse_cluster(socket, 0, -1, 0);
673 
674 	return ret;
675 }
676 
677 static int __init parse_dt_topology(void)
678 {
679 	struct device_node *cn, *map;
680 	int ret = 0;
681 	int cpu;
682 
683 	cn = of_find_node_by_path("/cpus");
684 	if (!cn) {
685 		pr_err("No CPU information found in DT\n");
686 		return 0;
687 	}
688 
689 	/*
690 	 * When topology is provided cpu-map is essentially a root
691 	 * cluster with restricted subnodes.
692 	 */
693 	map = of_get_child_by_name(cn, "cpu-map");
694 	if (!map)
695 		goto out;
696 
697 	ret = parse_socket(map);
698 	if (ret != 0)
699 		goto out_map;
700 
701 	topology_normalize_cpu_scale();
702 
703 	/*
704 	 * Check that all cores are in the topology; the SMP code will
705 	 * only mark cores described in the DT as possible.
706 	 */
707 	for_each_possible_cpu(cpu)
708 		if (cpu_topology[cpu].package_id < 0) {
709 			ret = -EINVAL;
710 			break;
711 		}
712 
713 out_map:
714 	of_node_put(map);
715 out:
716 	of_node_put(cn);
717 	return ret;
718 }
719 #endif
720 
721 /*
722  * cpu topology table
723  */
724 struct cpu_topology cpu_topology[NR_CPUS];
725 EXPORT_SYMBOL_GPL(cpu_topology);
726 
727 const struct cpumask *cpu_coregroup_mask(int cpu)
728 {
729 	const cpumask_t *core_mask = cpumask_of_node(cpu_to_node(cpu));
730 
731 	/* Find the smaller of NUMA, core or LLC siblings */
732 	if (cpumask_subset(&cpu_topology[cpu].core_sibling, core_mask)) {
733 		/* not numa in package, lets use the package siblings */
734 		core_mask = &cpu_topology[cpu].core_sibling;
735 	}
736 
737 	if (last_level_cache_is_valid(cpu)) {
738 		if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask))
739 			core_mask = &cpu_topology[cpu].llc_sibling;
740 	}
741 
742 	/*
743 	 * For systems with no shared cpu-side LLC but with clusters defined,
744 	 * extend core_mask to cluster_siblings. The sched domain builder will
745 	 * then remove MC as redundant with CLS if SCHED_CLUSTER is enabled.
746 	 */
747 	if (IS_ENABLED(CONFIG_SCHED_CLUSTER) &&
748 	    cpumask_subset(core_mask, &cpu_topology[cpu].cluster_sibling))
749 		core_mask = &cpu_topology[cpu].cluster_sibling;
750 
751 	return core_mask;
752 }
753 
754 const struct cpumask *cpu_clustergroup_mask(int cpu)
755 {
756 	/*
757 	 * Forbid cpu_clustergroup_mask() to span more or the same CPUs as
758 	 * cpu_coregroup_mask().
759 	 */
760 	if (cpumask_subset(cpu_coregroup_mask(cpu),
761 			   &cpu_topology[cpu].cluster_sibling))
762 		return topology_sibling_cpumask(cpu);
763 
764 	return &cpu_topology[cpu].cluster_sibling;
765 }
766 
767 void update_siblings_masks(unsigned int cpuid)
768 {
769 	struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
770 	int cpu, ret;
771 
772 	ret = detect_cache_attributes(cpuid);
773 	if (ret && ret != -ENOENT)
774 		pr_info("Early cacheinfo allocation failed, ret = %d\n", ret);
775 
776 	/* update core and thread sibling masks */
777 	for_each_online_cpu(cpu) {
778 		cpu_topo = &cpu_topology[cpu];
779 
780 		if (last_level_cache_is_shared(cpu, cpuid)) {
781 			cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
782 			cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
783 		}
784 
785 		if (cpuid_topo->package_id != cpu_topo->package_id)
786 			continue;
787 
788 		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
789 		cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
790 
791 		if (cpuid_topo->cluster_id != cpu_topo->cluster_id)
792 			continue;
793 
794 		if (cpuid_topo->cluster_id >= 0) {
795 			cpumask_set_cpu(cpu, &cpuid_topo->cluster_sibling);
796 			cpumask_set_cpu(cpuid, &cpu_topo->cluster_sibling);
797 		}
798 
799 		if (cpuid_topo->core_id != cpu_topo->core_id)
800 			continue;
801 
802 		cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
803 		cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
804 	}
805 }
806 
807 static void clear_cpu_topology(int cpu)
808 {
809 	struct cpu_topology *cpu_topo = &cpu_topology[cpu];
810 
811 	cpumask_clear(&cpu_topo->llc_sibling);
812 	cpumask_set_cpu(cpu, &cpu_topo->llc_sibling);
813 
814 	cpumask_clear(&cpu_topo->cluster_sibling);
815 	cpumask_set_cpu(cpu, &cpu_topo->cluster_sibling);
816 
817 	cpumask_clear(&cpu_topo->core_sibling);
818 	cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
819 	cpumask_clear(&cpu_topo->thread_sibling);
820 	cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
821 }
822 
823 void __init reset_cpu_topology(void)
824 {
825 	unsigned int cpu;
826 
827 	for_each_possible_cpu(cpu) {
828 		struct cpu_topology *cpu_topo = &cpu_topology[cpu];
829 
830 		cpu_topo->thread_id = -1;
831 		cpu_topo->core_id = -1;
832 		cpu_topo->cluster_id = -1;
833 		cpu_topo->package_id = -1;
834 
835 		clear_cpu_topology(cpu);
836 	}
837 }
838 
839 void remove_cpu_topology(unsigned int cpu)
840 {
841 	int sibling;
842 
843 	for_each_cpu(sibling, topology_core_cpumask(cpu))
844 		cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
845 	for_each_cpu(sibling, topology_sibling_cpumask(cpu))
846 		cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
847 	for_each_cpu(sibling, topology_cluster_cpumask(cpu))
848 		cpumask_clear_cpu(cpu, topology_cluster_cpumask(sibling));
849 	for_each_cpu(sibling, topology_llc_cpumask(cpu))
850 		cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling));
851 
852 	clear_cpu_topology(cpu);
853 }
854 
855 __weak int __init parse_acpi_topology(void)
856 {
857 	return 0;
858 }
859 
860 #if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
861 void __init init_cpu_topology(void)
862 {
863 	int cpu, ret;
864 
865 	reset_cpu_topology();
866 	ret = parse_acpi_topology();
867 	if (!ret)
868 		ret = of_have_populated_dt() && parse_dt_topology();
869 
870 	if (ret) {
871 		/*
872 		 * Discard anything that was parsed if we hit an error so we
873 		 * don't use partial information. But do not return yet to give
874 		 * arch-specific early cache level detection a chance to run.
875 		 */
876 		reset_cpu_topology();
877 	}
878 
879 	for_each_possible_cpu(cpu) {
880 		ret = fetch_cache_info(cpu);
881 		if (!ret)
882 			continue;
883 		else if (ret != -ENOENT)
884 			pr_err("Early cacheinfo failed, ret = %d\n", ret);
885 		return;
886 	}
887 }
888 
889 void store_cpu_topology(unsigned int cpuid)
890 {
891 	struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
892 
893 	if (cpuid_topo->package_id != -1)
894 		goto topology_populated;
895 
896 	cpuid_topo->thread_id = -1;
897 	cpuid_topo->core_id = cpuid;
898 	cpuid_topo->package_id = cpu_to_node(cpuid);
899 
900 	pr_debug("CPU%u: package %d core %d thread %d\n",
901 		 cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
902 		 cpuid_topo->thread_id);
903 
904 topology_populated:
905 	update_siblings_masks(cpuid);
906 }
907 #endif
908