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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/cpu.h>
11#include <linux/cpufreq.h>
12#include <linux/device.h>
13#include <linux/of.h>
14#include <linux/slab.h>
15#include <linux/string.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/percpu.h>
21#include <linux/rcupdate.h>
22#include <linux/sched.h>
23#include <linux/smp.h>
24
25static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data);
26static struct cpumask scale_freq_counters_mask;
27static bool scale_freq_invariant;
28
29static bool supports_scale_freq_counters(const struct cpumask *cpus)
30{
31 return cpumask_subset(cpus, &scale_freq_counters_mask);
32}
33
34bool topology_scale_freq_invariant(void)
35{
36 return cpufreq_supports_freq_invariance() ||
37 supports_scale_freq_counters(cpu_online_mask);
38}
39
40static void update_scale_freq_invariant(bool status)
41{
42 if (scale_freq_invariant == status)
43 return;
44
45 /*
46 * Task scheduler behavior depends on frequency invariance support,
47 * either cpufreq or counter driven. If the support status changes as
48 * a result of counter initialisation and use, retrigger the build of
49 * scheduling domains to ensure the information is propagated properly.
50 */
51 if (topology_scale_freq_invariant() == status) {
52 scale_freq_invariant = status;
53 rebuild_sched_domains_energy();
54 }
55}
56
57void topology_set_scale_freq_source(struct scale_freq_data *data,
58 const struct cpumask *cpus)
59{
60 struct scale_freq_data *sfd;
61 int cpu;
62
63 /*
64 * Avoid calling rebuild_sched_domains() unnecessarily if FIE is
65 * supported by cpufreq.
66 */
67 if (cpumask_empty(&scale_freq_counters_mask))
68 scale_freq_invariant = topology_scale_freq_invariant();
69
70 rcu_read_lock();
71
72 for_each_cpu(cpu, cpus) {
73 sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));
74
75 /* Use ARCH provided counters whenever possible */
76 if (!sfd || sfd->source != SCALE_FREQ_SOURCE_ARCH) {
77 rcu_assign_pointer(per_cpu(sft_data, cpu), data);
78 cpumask_set_cpu(cpu, &scale_freq_counters_mask);
79 }
80 }
81
82 rcu_read_unlock();
83
84 update_scale_freq_invariant(true);
85}
86EXPORT_SYMBOL_GPL(topology_set_scale_freq_source);
87
88void topology_clear_scale_freq_source(enum scale_freq_source source,
89 const struct cpumask *cpus)
90{
91 struct scale_freq_data *sfd;
92 int cpu;
93
94 rcu_read_lock();
95
96 for_each_cpu(cpu, cpus) {
97 sfd = rcu_dereference(*per_cpu_ptr(&sft_data, cpu));
98
99 if (sfd && sfd->source == source) {
100 rcu_assign_pointer(per_cpu(sft_data, cpu), NULL);
101 cpumask_clear_cpu(cpu, &scale_freq_counters_mask);
102 }
103 }
104
105 rcu_read_unlock();
106
107 /*
108 * Make sure all references to previous sft_data are dropped to avoid
109 * use-after-free races.
110 */
111 synchronize_rcu();
112
113 update_scale_freq_invariant(false);
114}
115EXPORT_SYMBOL_GPL(topology_clear_scale_freq_source);
116
117void topology_scale_freq_tick(void)
118{
119 struct scale_freq_data *sfd = rcu_dereference_sched(*this_cpu_ptr(&sft_data));
120
121 if (sfd)
122 sfd->set_freq_scale();
123}
124
125DEFINE_PER_CPU(unsigned long, arch_freq_scale) = SCHED_CAPACITY_SCALE;
126EXPORT_PER_CPU_SYMBOL_GPL(arch_freq_scale);
127
128void topology_set_freq_scale(const struct cpumask *cpus, unsigned long cur_freq,
129 unsigned long max_freq)
130{
131 unsigned long scale;
132 int i;
133
134 if (WARN_ON_ONCE(!cur_freq || !max_freq))
135 return;
136
137 /*
138 * If the use of counters for FIE is enabled, just return as we don't
139 * want to update the scale factor with information from CPUFREQ.
140 * Instead the scale factor will be updated from arch_scale_freq_tick.
141 */
142 if (supports_scale_freq_counters(cpus))
143 return;
144
145 scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
146
147 for_each_cpu(i, cpus)
148 per_cpu(arch_freq_scale, i) = scale;
149}
150
151DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
152
153void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity)
154{
155 per_cpu(cpu_scale, cpu) = capacity;
156}
157
158DEFINE_PER_CPU(unsigned long, thermal_pressure);
159
160void topology_set_thermal_pressure(const struct cpumask *cpus,
161 unsigned long th_pressure)
162{
163 int cpu;
164
165 for_each_cpu(cpu, cpus)
166 WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
167}
168
169static ssize_t cpu_capacity_show(struct device *dev,
170 struct device_attribute *attr,
171 char *buf)
172{
173 struct cpu *cpu = container_of(dev, struct cpu, dev);
174
175 return sysfs_emit(buf, "%lu\n", topology_get_cpu_scale(cpu->dev.id));
176}
177
178static void update_topology_flags_workfn(struct work_struct *work);
179static DECLARE_WORK(update_topology_flags_work, update_topology_flags_workfn);
180
181static DEVICE_ATTR_RO(cpu_capacity);
182
183static int register_cpu_capacity_sysctl(void)
184{
185 int i;
186 struct device *cpu;
187
188 for_each_possible_cpu(i) {
189 cpu = get_cpu_device(i);
190 if (!cpu) {
191 pr_err("%s: too early to get CPU%d device!\n",
192 __func__, i);
193 continue;
194 }
195 device_create_file(cpu, &dev_attr_cpu_capacity);
196 }
197
198 return 0;
199}
200subsys_initcall(register_cpu_capacity_sysctl);
201
202static int update_topology;
203
204int topology_update_cpu_topology(void)
205{
206 return update_topology;
207}
208
209/*
210 * Updating the sched_domains can't be done directly from cpufreq callbacks
211 * due to locking, so queue the work for later.
212 */
213static void update_topology_flags_workfn(struct work_struct *work)
214{
215 update_topology = 1;
216 rebuild_sched_domains();
217 pr_debug("sched_domain hierarchy rebuilt, flags updated\n");
218 update_topology = 0;
219}
220
221static DEFINE_PER_CPU(u32, freq_factor) = 1;
222static u32 *raw_capacity;
223
224static int free_raw_capacity(void)
225{
226 kfree(raw_capacity);
227 raw_capacity = NULL;
228
229 return 0;
230}
231
232void topology_normalize_cpu_scale(void)
233{
234 u64 capacity;
235 u64 capacity_scale;
236 int cpu;
237
238 if (!raw_capacity)
239 return;
240
241 capacity_scale = 1;
242 for_each_possible_cpu(cpu) {
243 capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
244 capacity_scale = max(capacity, capacity_scale);
245 }
246
247 pr_debug("cpu_capacity: capacity_scale=%llu\n", capacity_scale);
248 for_each_possible_cpu(cpu) {
249 capacity = raw_capacity[cpu] * per_cpu(freq_factor, cpu);
250 capacity = div64_u64(capacity << SCHED_CAPACITY_SHIFT,
251 capacity_scale);
252 topology_set_cpu_scale(cpu, capacity);
253 pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n",
254 cpu, topology_get_cpu_scale(cpu));
255 }
256}
257
258bool __init topology_parse_cpu_capacity(struct device_node *cpu_node, int cpu)
259{
260 struct clk *cpu_clk;
261 static bool cap_parsing_failed;
262 int ret;
263 u32 cpu_capacity;
264
265 if (cap_parsing_failed)
266 return false;
267
268 ret = of_property_read_u32(cpu_node, "capacity-dmips-mhz",
269 &cpu_capacity);
270 if (!ret) {
271 if (!raw_capacity) {
272 raw_capacity = kcalloc(num_possible_cpus(),
273 sizeof(*raw_capacity),
274 GFP_KERNEL);
275 if (!raw_capacity) {
276 cap_parsing_failed = true;
277 return false;
278 }
279 }
280 raw_capacity[cpu] = cpu_capacity;
281 pr_debug("cpu_capacity: %pOF cpu_capacity=%u (raw)\n",
282 cpu_node, raw_capacity[cpu]);
283
284 /*
285 * Update freq_factor for calculating early boot cpu capacities.
286 * For non-clk CPU DVFS mechanism, there's no way to get the
287 * frequency value now, assuming they are running at the same
288 * frequency (by keeping the initial freq_factor value).
289 */
290 cpu_clk = of_clk_get(cpu_node, 0);
291 if (!PTR_ERR_OR_ZERO(cpu_clk)) {
292 per_cpu(freq_factor, cpu) =
293 clk_get_rate(cpu_clk) / 1000;
294 clk_put(cpu_clk);
295 }
296 } else {
297 if (raw_capacity) {
298 pr_err("cpu_capacity: missing %pOF raw capacity\n",
299 cpu_node);
300 pr_err("cpu_capacity: partial information: fallback to 1024 for all CPUs\n");
301 }
302 cap_parsing_failed = true;
303 free_raw_capacity();
304 }
305
306 return !ret;
307}
308
309#ifdef CONFIG_CPU_FREQ
310static cpumask_var_t cpus_to_visit;
311static void parsing_done_workfn(struct work_struct *work);
312static DECLARE_WORK(parsing_done_work, parsing_done_workfn);
313
314static int
315init_cpu_capacity_callback(struct notifier_block *nb,
316 unsigned long val,
317 void *data)
318{
319 struct cpufreq_policy *policy = data;
320 int cpu;
321
322 if (!raw_capacity)
323 return 0;
324
325 if (val != CPUFREQ_CREATE_POLICY)
326 return 0;
327
328 pr_debug("cpu_capacity: init cpu capacity for CPUs [%*pbl] (to_visit=%*pbl)\n",
329 cpumask_pr_args(policy->related_cpus),
330 cpumask_pr_args(cpus_to_visit));
331
332 cpumask_andnot(cpus_to_visit, cpus_to_visit, policy->related_cpus);
333
334 for_each_cpu(cpu, policy->related_cpus)
335 per_cpu(freq_factor, cpu) = policy->cpuinfo.max_freq / 1000;
336
337 if (cpumask_empty(cpus_to_visit)) {
338 topology_normalize_cpu_scale();
339 schedule_work(&update_topology_flags_work);
340 free_raw_capacity();
341 pr_debug("cpu_capacity: parsing done\n");
342 schedule_work(&parsing_done_work);
343 }
344
345 return 0;
346}
347
348static struct notifier_block init_cpu_capacity_notifier = {
349 .notifier_call = init_cpu_capacity_callback,
350};
351
352static int __init register_cpufreq_notifier(void)
353{
354 int ret;
355
356 /*
357 * on ACPI-based systems we need to use the default cpu capacity
358 * until we have the necessary code to parse the cpu capacity, so
359 * skip registering cpufreq notifier.
360 */
361 if (!acpi_disabled || !raw_capacity)
362 return -EINVAL;
363
364 if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL))
365 return -ENOMEM;
366
367 cpumask_copy(cpus_to_visit, cpu_possible_mask);
368
369 ret = cpufreq_register_notifier(&init_cpu_capacity_notifier,
370 CPUFREQ_POLICY_NOTIFIER);
371
372 if (ret)
373 free_cpumask_var(cpus_to_visit);
374
375 return ret;
376}
377core_initcall(register_cpufreq_notifier);
378
379static void parsing_done_workfn(struct work_struct *work)
380{
381 cpufreq_unregister_notifier(&init_cpu_capacity_notifier,
382 CPUFREQ_POLICY_NOTIFIER);
383 free_cpumask_var(cpus_to_visit);
384}
385
386#else
387core_initcall(free_raw_capacity);
388#endif
389
390#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
391/*
392 * This function returns the logic cpu number of the node.
393 * There are basically three kinds of return values:
394 * (1) logic cpu number which is > 0.
395 * (2) -ENODEV when the device tree(DT) node is valid and found in the DT but
396 * there is no possible logical CPU in the kernel to match. This happens
397 * when CONFIG_NR_CPUS is configure to be smaller than the number of
398 * CPU nodes in DT. We need to just ignore this case.
399 * (3) -1 if the node does not exist in the device tree
400 */
401static int __init get_cpu_for_node(struct device_node *node)
402{
403 struct device_node *cpu_node;
404 int cpu;
405
406 cpu_node = of_parse_phandle(node, "cpu", 0);
407 if (!cpu_node)
408 return -1;
409
410 cpu = of_cpu_node_to_id(cpu_node);
411 if (cpu >= 0)
412 topology_parse_cpu_capacity(cpu_node, cpu);
413 else
414 pr_info("CPU node for %pOF exist but the possible cpu range is :%*pbl\n",
415 cpu_node, cpumask_pr_args(cpu_possible_mask));
416
417 of_node_put(cpu_node);
418 return cpu;
419}
420
421static int __init parse_core(struct device_node *core, int package_id,
422 int core_id)
423{
424 char name[20];
425 bool leaf = true;
426 int i = 0;
427 int cpu;
428 struct device_node *t;
429
430 do {
431 snprintf(name, sizeof(name), "thread%d", i);
432 t = of_get_child_by_name(core, name);
433 if (t) {
434 leaf = false;
435 cpu = get_cpu_for_node(t);
436 if (cpu >= 0) {
437 cpu_topology[cpu].package_id = package_id;
438 cpu_topology[cpu].core_id = core_id;
439 cpu_topology[cpu].thread_id = i;
440 } else if (cpu != -ENODEV) {
441 pr_err("%pOF: Can't get CPU for thread\n", t);
442 of_node_put(t);
443 return -EINVAL;
444 }
445 of_node_put(t);
446 }
447 i++;
448 } while (t);
449
450 cpu = get_cpu_for_node(core);
451 if (cpu >= 0) {
452 if (!leaf) {
453 pr_err("%pOF: Core has both threads and CPU\n",
454 core);
455 return -EINVAL;
456 }
457
458 cpu_topology[cpu].package_id = package_id;
459 cpu_topology[cpu].core_id = core_id;
460 } else if (leaf && cpu != -ENODEV) {
461 pr_err("%pOF: Can't get CPU for leaf core\n", core);
462 return -EINVAL;
463 }
464
465 return 0;
466}
467
468static int __init parse_cluster(struct device_node *cluster, int depth)
469{
470 char name[20];
471 bool leaf = true;
472 bool has_cores = false;
473 struct device_node *c;
474 static int package_id __initdata;
475 int core_id = 0;
476 int i, ret;
477
478 /*
479 * First check for child clusters; we currently ignore any
480 * information about the nesting of clusters and present the
481 * scheduler with a flat list of them.
482 */
483 i = 0;
484 do {
485 snprintf(name, sizeof(name), "cluster%d", i);
486 c = of_get_child_by_name(cluster, name);
487 if (c) {
488 leaf = false;
489 ret = parse_cluster(c, depth + 1);
490 of_node_put(c);
491 if (ret != 0)
492 return ret;
493 }
494 i++;
495 } while (c);
496
497 /* Now check for cores */
498 i = 0;
499 do {
500 snprintf(name, sizeof(name), "core%d", i);
501 c = of_get_child_by_name(cluster, name);
502 if (c) {
503 has_cores = true;
504
505 if (depth == 0) {
506 pr_err("%pOF: cpu-map children should be clusters\n",
507 c);
508 of_node_put(c);
509 return -EINVAL;
510 }
511
512 if (leaf) {
513 ret = parse_core(c, package_id, core_id++);
514 } else {
515 pr_err("%pOF: Non-leaf cluster with core %s\n",
516 cluster, name);
517 ret = -EINVAL;
518 }
519
520 of_node_put(c);
521 if (ret != 0)
522 return ret;
523 }
524 i++;
525 } while (c);
526
527 if (leaf && !has_cores)
528 pr_warn("%pOF: empty cluster\n", cluster);
529
530 if (leaf)
531 package_id++;
532
533 return 0;
534}
535
536static int __init parse_dt_topology(void)
537{
538 struct device_node *cn, *map;
539 int ret = 0;
540 int cpu;
541
542 cn = of_find_node_by_path("/cpus");
543 if (!cn) {
544 pr_err("No CPU information found in DT\n");
545 return 0;
546 }
547
548 /*
549 * When topology is provided cpu-map is essentially a root
550 * cluster with restricted subnodes.
551 */
552 map = of_get_child_by_name(cn, "cpu-map");
553 if (!map)
554 goto out;
555
556 ret = parse_cluster(map, 0);
557 if (ret != 0)
558 goto out_map;
559
560 topology_normalize_cpu_scale();
561
562 /*
563 * Check that all cores are in the topology; the SMP code will
564 * only mark cores described in the DT as possible.
565 */
566 for_each_possible_cpu(cpu)
567 if (cpu_topology[cpu].package_id == -1)
568 ret = -EINVAL;
569
570out_map:
571 of_node_put(map);
572out:
573 of_node_put(cn);
574 return ret;
575}
576#endif
577
578/*
579 * cpu topology table
580 */
581struct cpu_topology cpu_topology[NR_CPUS];
582EXPORT_SYMBOL_GPL(cpu_topology);
583
584const struct cpumask *cpu_coregroup_mask(int cpu)
585{
586 const cpumask_t *core_mask = cpumask_of_node(cpu_to_node(cpu));
587
588 /* Find the smaller of NUMA, core or LLC siblings */
589 if (cpumask_subset(&cpu_topology[cpu].core_sibling, core_mask)) {
590 /* not numa in package, lets use the package siblings */
591 core_mask = &cpu_topology[cpu].core_sibling;
592 }
593 if (cpu_topology[cpu].llc_id != -1) {
594 if (cpumask_subset(&cpu_topology[cpu].llc_sibling, core_mask))
595 core_mask = &cpu_topology[cpu].llc_sibling;
596 }
597
598 return core_mask;
599}
600
601void update_siblings_masks(unsigned int cpuid)
602{
603 struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
604 int cpu;
605
606 /* update core and thread sibling masks */
607 for_each_online_cpu(cpu) {
608 cpu_topo = &cpu_topology[cpu];
609
610 if (cpuid_topo->llc_id == cpu_topo->llc_id) {
611 cpumask_set_cpu(cpu, &cpuid_topo->llc_sibling);
612 cpumask_set_cpu(cpuid, &cpu_topo->llc_sibling);
613 }
614
615 if (cpuid_topo->package_id != cpu_topo->package_id)
616 continue;
617
618 cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
619 cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
620
621 if (cpuid_topo->core_id != cpu_topo->core_id)
622 continue;
623
624 cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
625 cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
626 }
627}
628
629static void clear_cpu_topology(int cpu)
630{
631 struct cpu_topology *cpu_topo = &cpu_topology[cpu];
632
633 cpumask_clear(&cpu_topo->llc_sibling);
634 cpumask_set_cpu(cpu, &cpu_topo->llc_sibling);
635
636 cpumask_clear(&cpu_topo->core_sibling);
637 cpumask_set_cpu(cpu, &cpu_topo->core_sibling);
638 cpumask_clear(&cpu_topo->thread_sibling);
639 cpumask_set_cpu(cpu, &cpu_topo->thread_sibling);
640}
641
642void __init reset_cpu_topology(void)
643{
644 unsigned int cpu;
645
646 for_each_possible_cpu(cpu) {
647 struct cpu_topology *cpu_topo = &cpu_topology[cpu];
648
649 cpu_topo->thread_id = -1;
650 cpu_topo->core_id = -1;
651 cpu_topo->package_id = -1;
652 cpu_topo->llc_id = -1;
653
654 clear_cpu_topology(cpu);
655 }
656}
657
658void remove_cpu_topology(unsigned int cpu)
659{
660 int sibling;
661
662 for_each_cpu(sibling, topology_core_cpumask(cpu))
663 cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
664 for_each_cpu(sibling, topology_sibling_cpumask(cpu))
665 cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
666 for_each_cpu(sibling, topology_llc_cpumask(cpu))
667 cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling));
668
669 clear_cpu_topology(cpu);
670}
671
672__weak int __init parse_acpi_topology(void)
673{
674 return 0;
675}
676
677#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)
678void __init init_cpu_topology(void)
679{
680 reset_cpu_topology();
681
682 /*
683 * Discard anything that was parsed if we hit an error so we
684 * don't use partial information.
685 */
686 if (parse_acpi_topology())
687 reset_cpu_topology();
688 else if (of_have_populated_dt() && parse_dt_topology())
689 reset_cpu_topology();
690}
691#endif