1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright IBM Corp. 2007, 2011
4 */
5
6#define KMSG_COMPONENT "cpu"
7#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
8
9#include <linux/workqueue.h>
10#include <linux/memblock.h>
11#include <linux/uaccess.h>
12#include <linux/sysctl.h>
13#include <linux/cpuset.h>
14#include <linux/device.h>
15#include <linux/export.h>
16#include <linux/kernel.h>
17#include <linux/sched.h>
18#include <linux/sched/topology.h>
19#include <linux/delay.h>
20#include <linux/init.h>
21#include <linux/slab.h>
22#include <linux/cpu.h>
23#include <linux/smp.h>
24#include <linux/mm.h>
25#include <linux/nodemask.h>
26#include <linux/node.h>
27#include <asm/sysinfo.h>
28
29#define PTF_HORIZONTAL (0UL)
30#define PTF_VERTICAL (1UL)
31#define PTF_CHECK (2UL)
32
33enum {
34 TOPOLOGY_MODE_HW,
35 TOPOLOGY_MODE_SINGLE,
36 TOPOLOGY_MODE_PACKAGE,
37 TOPOLOGY_MODE_UNINITIALIZED
38};
39
40struct mask_info {
41 struct mask_info *next;
42 unsigned char id;
43 cpumask_t mask;
44};
45
46static int topology_mode = TOPOLOGY_MODE_UNINITIALIZED;
47static void set_topology_timer(void);
48static void topology_work_fn(struct work_struct *work);
49static struct sysinfo_15_1_x *tl_info;
50
51static DECLARE_WORK(topology_work, topology_work_fn);
52
53/*
54 * Socket/Book linked lists and cpu_topology updates are
55 * protected by "sched_domains_mutex".
56 */
57static struct mask_info socket_info;
58static struct mask_info book_info;
59static struct mask_info drawer_info;
60
61struct cpu_topology_s390 cpu_topology[NR_CPUS];
62EXPORT_SYMBOL_GPL(cpu_topology);
63
64static void cpu_group_map(cpumask_t *dst, struct mask_info *info, unsigned int cpu)
65{
66 static cpumask_t mask;
67
68 cpumask_clear(dstp: &mask);
69 if (!cpumask_test_cpu(cpu, cpumask: &cpu_setup_mask))
70 goto out;
71 cpumask_set_cpu(cpu, dstp: &mask);
72 switch (topology_mode) {
73 case TOPOLOGY_MODE_HW:
74 while (info) {
75 if (cpumask_test_cpu(cpu, cpumask: &info->mask)) {
76 cpumask_copy(dstp: &mask, srcp: &info->mask);
77 break;
78 }
79 info = info->next;
80 }
81 break;
82 case TOPOLOGY_MODE_PACKAGE:
83 cpumask_copy(dstp: &mask, cpu_present_mask);
84 break;
85 default:
86 fallthrough;
87 case TOPOLOGY_MODE_SINGLE:
88 break;
89 }
90 cpumask_and(dstp: &mask, src1p: &mask, src2p: &cpu_setup_mask);
91out:
92 cpumask_copy(dstp: dst, srcp: &mask);
93}
94
95static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
96{
97 static cpumask_t mask;
98 unsigned int max_cpu;
99
100 cpumask_clear(dstp: &mask);
101 if (!cpumask_test_cpu(cpu, cpumask: &cpu_setup_mask))
102 goto out;
103 cpumask_set_cpu(cpu, dstp: &mask);
104 if (topology_mode != TOPOLOGY_MODE_HW)
105 goto out;
106 cpu -= cpu % (smp_cpu_mtid + 1);
107 max_cpu = min(cpu + smp_cpu_mtid, nr_cpu_ids - 1);
108 for (; cpu <= max_cpu; cpu++) {
109 if (cpumask_test_cpu(cpu, cpumask: &cpu_setup_mask))
110 cpumask_set_cpu(cpu, dstp: &mask);
111 }
112out:
113 cpumask_copy(dstp: dst, srcp: &mask);
114}
115
116#define TOPOLOGY_CORE_BITS 64
117
118static void add_cpus_to_mask(struct topology_core *tl_core,
119 struct mask_info *drawer,
120 struct mask_info *book,
121 struct mask_info *socket)
122{
123 struct cpu_topology_s390 *topo;
124 unsigned int core;
125
126 for_each_set_bit(core, &tl_core->mask, TOPOLOGY_CORE_BITS) {
127 unsigned int max_cpu, rcore;
128 int cpu;
129
130 rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
131 cpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
132 if (cpu < 0)
133 continue;
134 max_cpu = min(cpu + smp_cpu_mtid, nr_cpu_ids - 1);
135 for (; cpu <= max_cpu; cpu++) {
136 topo = &cpu_topology[cpu];
137 topo->drawer_id = drawer->id;
138 topo->book_id = book->id;
139 topo->socket_id = socket->id;
140 topo->core_id = rcore;
141 topo->thread_id = cpu;
142 topo->dedicated = tl_core->d;
143 cpumask_set_cpu(cpu, dstp: &drawer->mask);
144 cpumask_set_cpu(cpu, dstp: &book->mask);
145 cpumask_set_cpu(cpu, dstp: &socket->mask);
146 smp_cpu_set_polarization(cpu, tl_core->pp);
147 }
148 }
149}
150
151static void clear_masks(void)
152{
153 struct mask_info *info;
154
155 info = &socket_info;
156 while (info) {
157 cpumask_clear(dstp: &info->mask);
158 info = info->next;
159 }
160 info = &book_info;
161 while (info) {
162 cpumask_clear(dstp: &info->mask);
163 info = info->next;
164 }
165 info = &drawer_info;
166 while (info) {
167 cpumask_clear(dstp: &info->mask);
168 info = info->next;
169 }
170}
171
172static union topology_entry *next_tle(union topology_entry *tle)
173{
174 if (!tle->nl)
175 return (union topology_entry *)((struct topology_core *)tle + 1);
176 return (union topology_entry *)((struct topology_container *)tle + 1);
177}
178
179static void tl_to_masks(struct sysinfo_15_1_x *info)
180{
181 struct mask_info *socket = &socket_info;
182 struct mask_info *book = &book_info;
183 struct mask_info *drawer = &drawer_info;
184 union topology_entry *tle, *end;
185
186 clear_masks();
187 tle = info->tle;
188 end = (union topology_entry *)((unsigned long)info + info->length);
189 while (tle < end) {
190 switch (tle->nl) {
191 case 3:
192 drawer = drawer->next;
193 drawer->id = tle->container.id;
194 break;
195 case 2:
196 book = book->next;
197 book->id = tle->container.id;
198 break;
199 case 1:
200 socket = socket->next;
201 socket->id = tle->container.id;
202 break;
203 case 0:
204 add_cpus_to_mask(tl_core: &tle->cpu, drawer, book, socket);
205 break;
206 default:
207 clear_masks();
208 return;
209 }
210 tle = next_tle(tle);
211 }
212}
213
214static void topology_update_polarization_simple(void)
215{
216 int cpu;
217
218 for_each_possible_cpu(cpu)
219 smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
220}
221
222static int ptf(unsigned long fc)
223{
224 int rc;
225
226 asm volatile(
227 " .insn rre,0xb9a20000,%1,%1\n"
228 " ipm %0\n"
229 " srl %0,28\n"
230 : "=d" (rc)
231 : "d" (fc) : "cc");
232 return rc;
233}
234
235int topology_set_cpu_management(int fc)
236{
237 int cpu, rc;
238
239 if (!MACHINE_HAS_TOPOLOGY)
240 return -EOPNOTSUPP;
241 if (fc)
242 rc = ptf(PTF_VERTICAL);
243 else
244 rc = ptf(PTF_HORIZONTAL);
245 if (rc)
246 return -EBUSY;
247 for_each_possible_cpu(cpu)
248 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
249 return rc;
250}
251
252void update_cpu_masks(void)
253{
254 struct cpu_topology_s390 *topo, *topo_package, *topo_sibling;
255 int cpu, sibling, pkg_first, smt_first, id;
256
257 for_each_possible_cpu(cpu) {
258 topo = &cpu_topology[cpu];
259 cpu_thread_map(dst: &topo->thread_mask, cpu);
260 cpu_group_map(dst: &topo->core_mask, info: &socket_info, cpu);
261 cpu_group_map(dst: &topo->book_mask, info: &book_info, cpu);
262 cpu_group_map(dst: &topo->drawer_mask, info: &drawer_info, cpu);
263 topo->booted_cores = 0;
264 if (topology_mode != TOPOLOGY_MODE_HW) {
265 id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
266 topo->thread_id = cpu;
267 topo->core_id = cpu;
268 topo->socket_id = id;
269 topo->book_id = id;
270 topo->drawer_id = id;
271 }
272 }
273 for_each_online_cpu(cpu) {
274 topo = &cpu_topology[cpu];
275 pkg_first = cpumask_first(srcp: &topo->core_mask);
276 topo_package = &cpu_topology[pkg_first];
277 if (cpu == pkg_first) {
278 for_each_cpu(sibling, &topo->core_mask) {
279 topo_sibling = &cpu_topology[sibling];
280 smt_first = cpumask_first(srcp: &topo_sibling->thread_mask);
281 if (sibling == smt_first)
282 topo_package->booted_cores++;
283 }
284 } else {
285 topo->booted_cores = topo_package->booted_cores;
286 }
287 }
288}
289
290void store_topology(struct sysinfo_15_1_x *info)
291{
292 stsi(info, 15, 1, topology_mnest_limit());
293}
294
295static void __arch_update_dedicated_flag(void *arg)
296{
297 if (topology_cpu_dedicated(smp_processor_id()))
298 set_cpu_flag(CIF_DEDICATED_CPU);
299 else
300 clear_cpu_flag(CIF_DEDICATED_CPU);
301}
302
303static int __arch_update_cpu_topology(void)
304{
305 struct sysinfo_15_1_x *info = tl_info;
306 int rc = 0;
307
308 mutex_lock(&smp_cpu_state_mutex);
309 if (MACHINE_HAS_TOPOLOGY) {
310 rc = 1;
311 store_topology(info);
312 tl_to_masks(info);
313 }
314 update_cpu_masks();
315 if (!MACHINE_HAS_TOPOLOGY)
316 topology_update_polarization_simple();
317 mutex_unlock(lock: &smp_cpu_state_mutex);
318 return rc;
319}
320
321int arch_update_cpu_topology(void)
322{
323 struct device *dev;
324 int cpu, rc;
325
326 rc = __arch_update_cpu_topology();
327 on_each_cpu(func: __arch_update_dedicated_flag, NULL, wait: 0);
328 for_each_online_cpu(cpu) {
329 dev = get_cpu_device(cpu);
330 if (dev)
331 kobject_uevent(kobj: &dev->kobj, action: KOBJ_CHANGE);
332 }
333 return rc;
334}
335
336static void topology_work_fn(struct work_struct *work)
337{
338 rebuild_sched_domains();
339}
340
341void topology_schedule_update(void)
342{
343 schedule_work(work: &topology_work);
344}
345
346static void topology_flush_work(void)
347{
348 flush_work(work: &topology_work);
349}
350
351static void topology_timer_fn(struct timer_list *unused)
352{
353 if (ptf(PTF_CHECK))
354 topology_schedule_update();
355 set_topology_timer();
356}
357
358static struct timer_list topology_timer;
359
360static atomic_t topology_poll = ATOMIC_INIT(0);
361
362static void set_topology_timer(void)
363{
364 if (atomic_add_unless(v: &topology_poll, a: -1, u: 0))
365 mod_timer(timer: &topology_timer, expires: jiffies + msecs_to_jiffies(m: 100));
366 else
367 mod_timer(timer: &topology_timer, expires: jiffies + msecs_to_jiffies(m: 60 * MSEC_PER_SEC));
368}
369
370void topology_expect_change(void)
371{
372 if (!MACHINE_HAS_TOPOLOGY)
373 return;
374 /* This is racy, but it doesn't matter since it is just a heuristic.
375 * Worst case is that we poll in a higher frequency for a bit longer.
376 */
377 if (atomic_read(v: &topology_poll) > 60)
378 return;
379 atomic_add(i: 60, v: &topology_poll);
380 set_topology_timer();
381}
382
383static int cpu_management;
384
385static ssize_t dispatching_show(struct device *dev,
386 struct device_attribute *attr,
387 char *buf)
388{
389 ssize_t count;
390
391 mutex_lock(&smp_cpu_state_mutex);
392 count = sprintf(buf, fmt: "%d\n", cpu_management);
393 mutex_unlock(lock: &smp_cpu_state_mutex);
394 return count;
395}
396
397static ssize_t dispatching_store(struct device *dev,
398 struct device_attribute *attr,
399 const char *buf,
400 size_t count)
401{
402 int val, rc;
403 char delim;
404
405 if (sscanf(buf, "%d %c", &val, &delim) != 1)
406 return -EINVAL;
407 if (val != 0 && val != 1)
408 return -EINVAL;
409 rc = 0;
410 cpus_read_lock();
411 mutex_lock(&smp_cpu_state_mutex);
412 if (cpu_management == val)
413 goto out;
414 rc = topology_set_cpu_management(fc: val);
415 if (rc)
416 goto out;
417 cpu_management = val;
418 topology_expect_change();
419out:
420 mutex_unlock(lock: &smp_cpu_state_mutex);
421 cpus_read_unlock();
422 return rc ? rc : count;
423}
424static DEVICE_ATTR_RW(dispatching);
425
426static ssize_t cpu_polarization_show(struct device *dev,
427 struct device_attribute *attr, char *buf)
428{
429 int cpu = dev->id;
430 ssize_t count;
431
432 mutex_lock(&smp_cpu_state_mutex);
433 switch (smp_cpu_get_polarization(cpu)) {
434 case POLARIZATION_HRZ:
435 count = sprintf(buf, fmt: "horizontal\n");
436 break;
437 case POLARIZATION_VL:
438 count = sprintf(buf, fmt: "vertical:low\n");
439 break;
440 case POLARIZATION_VM:
441 count = sprintf(buf, fmt: "vertical:medium\n");
442 break;
443 case POLARIZATION_VH:
444 count = sprintf(buf, fmt: "vertical:high\n");
445 break;
446 default:
447 count = sprintf(buf, fmt: "unknown\n");
448 break;
449 }
450 mutex_unlock(lock: &smp_cpu_state_mutex);
451 return count;
452}
453static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
454
455static struct attribute *topology_cpu_attrs[] = {
456 &dev_attr_polarization.attr,
457 NULL,
458};
459
460static struct attribute_group topology_cpu_attr_group = {
461 .attrs = topology_cpu_attrs,
462};
463
464static ssize_t cpu_dedicated_show(struct device *dev,
465 struct device_attribute *attr, char *buf)
466{
467 int cpu = dev->id;
468 ssize_t count;
469
470 mutex_lock(&smp_cpu_state_mutex);
471 count = sprintf(buf, fmt: "%d\n", topology_cpu_dedicated(cpu));
472 mutex_unlock(lock: &smp_cpu_state_mutex);
473 return count;
474}
475static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
476
477static struct attribute *topology_extra_cpu_attrs[] = {
478 &dev_attr_dedicated.attr,
479 NULL,
480};
481
482static struct attribute_group topology_extra_cpu_attr_group = {
483 .attrs = topology_extra_cpu_attrs,
484};
485
486int topology_cpu_init(struct cpu *cpu)
487{
488 int rc;
489
490 rc = sysfs_create_group(kobj: &cpu->dev.kobj, grp: &topology_cpu_attr_group);
491 if (rc || !MACHINE_HAS_TOPOLOGY)
492 return rc;
493 rc = sysfs_create_group(kobj: &cpu->dev.kobj, grp: &topology_extra_cpu_attr_group);
494 if (rc)
495 sysfs_remove_group(kobj: &cpu->dev.kobj, grp: &topology_cpu_attr_group);
496 return rc;
497}
498
499static const struct cpumask *cpu_thread_mask(int cpu)
500{
501 return &cpu_topology[cpu].thread_mask;
502}
503
504
505const struct cpumask *cpu_coregroup_mask(int cpu)
506{
507 return &cpu_topology[cpu].core_mask;
508}
509
510static const struct cpumask *cpu_book_mask(int cpu)
511{
512 return &cpu_topology[cpu].book_mask;
513}
514
515static const struct cpumask *cpu_drawer_mask(int cpu)
516{
517 return &cpu_topology[cpu].drawer_mask;
518}
519
520static struct sched_domain_topology_level s390_topology[] = {
521 { cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
522 { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
523 { cpu_book_mask, SD_INIT_NAME(BOOK) },
524 { cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
525 { cpu_cpu_mask, SD_INIT_NAME(PKG) },
526 { NULL, },
527};
528
529static void __init alloc_masks(struct sysinfo_15_1_x *info,
530 struct mask_info *mask, int offset)
531{
532 int i, nr_masks;
533
534 nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
535 for (i = 0; i < info->mnest - offset; i++)
536 nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
537 nr_masks = max(nr_masks, 1);
538 for (i = 0; i < nr_masks; i++) {
539 mask->next = memblock_alloc(size: sizeof(*mask->next), align: 8);
540 if (!mask->next)
541 panic(fmt: "%s: Failed to allocate %zu bytes align=0x%x\n",
542 __func__, sizeof(*mask->next), 8);
543 mask = mask->next;
544 }
545}
546
547void __init topology_init_early(void)
548{
549 struct sysinfo_15_1_x *info;
550
551 set_sched_topology(s390_topology);
552 if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
553 if (MACHINE_HAS_TOPOLOGY)
554 topology_mode = TOPOLOGY_MODE_HW;
555 else
556 topology_mode = TOPOLOGY_MODE_SINGLE;
557 }
558 if (!MACHINE_HAS_TOPOLOGY)
559 goto out;
560 tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
561 if (!tl_info)
562 panic(fmt: "%s: Failed to allocate %lu bytes align=0x%lx\n",
563 __func__, PAGE_SIZE, PAGE_SIZE);
564 info = tl_info;
565 store_topology(info);
566 pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
567 info->mag[0], info->mag[1], info->mag[2], info->mag[3],
568 info->mag[4], info->mag[5], info->mnest);
569 alloc_masks(info, mask: &socket_info, offset: 1);
570 alloc_masks(info, mask: &book_info, offset: 2);
571 alloc_masks(info, mask: &drawer_info, offset: 3);
572out:
573 cpumask_set_cpu(cpu: 0, dstp: &cpu_setup_mask);
574 __arch_update_cpu_topology();
575 __arch_update_dedicated_flag(NULL);
576}
577
578static inline int topology_get_mode(int enabled)
579{
580 if (!enabled)
581 return TOPOLOGY_MODE_SINGLE;
582 return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
583}
584
585static inline int topology_is_enabled(void)
586{
587 return topology_mode != TOPOLOGY_MODE_SINGLE;
588}
589
590static int __init topology_setup(char *str)
591{
592 bool enabled;
593 int rc;
594
595 rc = kstrtobool(s: str, res: &enabled);
596 if (rc)
597 return rc;
598 topology_mode = topology_get_mode(enabled);
599 return 0;
600}
601early_param("topology", topology_setup);
602
603static int topology_ctl_handler(struct ctl_table *ctl, int write,
604 void *buffer, size_t *lenp, loff_t *ppos)
605{
606 int enabled = topology_is_enabled();
607 int new_mode;
608 int rc;
609 struct ctl_table ctl_entry = {
610 .procname = ctl->procname,
611 .data = &enabled,
612 .maxlen = sizeof(int),
613 .extra1 = SYSCTL_ZERO,
614 .extra2 = SYSCTL_ONE,
615 };
616
617 rc = proc_douintvec_minmax(table: &ctl_entry, write, buffer, lenp, ppos);
618 if (rc < 0 || !write)
619 return rc;
620
621 mutex_lock(&smp_cpu_state_mutex);
622 new_mode = topology_get_mode(enabled);
623 if (topology_mode != new_mode) {
624 topology_mode = new_mode;
625 topology_schedule_update();
626 }
627 mutex_unlock(&smp_cpu_state_mutex);
628 topology_flush_work();
629
630 return rc;
631}
632
633static struct ctl_table topology_ctl_table[] = {
634 {
635 .procname = "topology",
636 .mode = 0644,
637 .proc_handler = topology_ctl_handler,
638 },
639};
640
641static int __init topology_init(void)
642{
643 struct device *dev_root;
644 int rc = 0;
645
646 timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
647 if (MACHINE_HAS_TOPOLOGY)
648 set_topology_timer();
649 else
650 topology_update_polarization_simple();
651 register_sysctl("s390", topology_ctl_table);
652
653 dev_root = bus_get_dev_root(bus: &cpu_subsys);
654 if (dev_root) {
655 rc = device_create_file(device: dev_root, entry: &dev_attr_dispatching);
656 put_device(dev: dev_root);
657 }
658 return rc;
659}
660device_initcall(topology_init);
661

source code of linux/arch/s390/kernel/topology.c