xref: /openbmc/linux/arch/s390/kernel/topology.c (revision 9659281c)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *    Copyright IBM Corp. 2007, 2011
4  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
5  */
6 
7 #define KMSG_COMPONENT "cpu"
8 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
9 
10 #include <linux/workqueue.h>
11 #include <linux/memblock.h>
12 #include <linux/uaccess.h>
13 #include <linux/sysctl.h>
14 #include <linux/cpuset.h>
15 #include <linux/device.h>
16 #include <linux/export.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/sched/topology.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/slab.h>
23 #include <linux/cpu.h>
24 #include <linux/smp.h>
25 #include <linux/mm.h>
26 #include <linux/nodemask.h>
27 #include <linux/node.h>
28 #include <asm/sysinfo.h>
29 
30 #define PTF_HORIZONTAL	(0UL)
31 #define PTF_VERTICAL	(1UL)
32 #define PTF_CHECK	(2UL)
33 
34 enum {
35 	TOPOLOGY_MODE_HW,
36 	TOPOLOGY_MODE_SINGLE,
37 	TOPOLOGY_MODE_PACKAGE,
38 	TOPOLOGY_MODE_UNINITIALIZED
39 };
40 
41 struct mask_info {
42 	struct mask_info *next;
43 	unsigned char id;
44 	cpumask_t mask;
45 };
46 
47 static int topology_mode = TOPOLOGY_MODE_UNINITIALIZED;
48 static void set_topology_timer(void);
49 static void topology_work_fn(struct work_struct *work);
50 static struct sysinfo_15_1_x *tl_info;
51 
52 static DECLARE_WORK(topology_work, topology_work_fn);
53 
54 /*
55  * Socket/Book linked lists and cpu_topology updates are
56  * protected by "sched_domains_mutex".
57  */
58 static struct mask_info socket_info;
59 static struct mask_info book_info;
60 static struct mask_info drawer_info;
61 
62 struct cpu_topology_s390 cpu_topology[NR_CPUS];
63 EXPORT_SYMBOL_GPL(cpu_topology);
64 
65 static void cpu_group_map(cpumask_t *dst, struct mask_info *info, unsigned int cpu)
66 {
67 	static cpumask_t mask;
68 
69 	cpumask_clear(&mask);
70 	if (!cpu_online(cpu))
71 		goto out;
72 	cpumask_set_cpu(cpu, &mask);
73 	switch (topology_mode) {
74 	case TOPOLOGY_MODE_HW:
75 		while (info) {
76 			if (cpumask_test_cpu(cpu, &info->mask)) {
77 				cpumask_copy(&mask, &info->mask);
78 				break;
79 			}
80 			info = info->next;
81 		}
82 		break;
83 	case TOPOLOGY_MODE_PACKAGE:
84 		cpumask_copy(&mask, cpu_present_mask);
85 		break;
86 	default:
87 		fallthrough;
88 	case TOPOLOGY_MODE_SINGLE:
89 		break;
90 	}
91 	cpumask_and(&mask, &mask, cpu_online_mask);
92 out:
93 	cpumask_copy(dst, &mask);
94 }
95 
96 static void cpu_thread_map(cpumask_t *dst, unsigned int cpu)
97 {
98 	static cpumask_t mask;
99 	int i;
100 
101 	cpumask_clear(&mask);
102 	if (!cpu_online(cpu))
103 		goto out;
104 	cpumask_set_cpu(cpu, &mask);
105 	if (topology_mode != TOPOLOGY_MODE_HW)
106 		goto out;
107 	cpu -= cpu % (smp_cpu_mtid + 1);
108 	for (i = 0; i <= smp_cpu_mtid; i++)
109 		if (cpu_present(cpu + i))
110 			cpumask_set_cpu(cpu + i, &mask);
111 	cpumask_and(&mask, &mask, cpu_online_mask);
112 out:
113 	cpumask_copy(dst, &mask);
114 }
115 
116 #define TOPOLOGY_CORE_BITS	64
117 
118 static 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 rcore;
128 		int lcpu, i;
129 
130 		rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
131 		lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
132 		if (lcpu < 0)
133 			continue;
134 		for (i = 0; i <= smp_cpu_mtid; i++) {
135 			topo = &cpu_topology[lcpu + i];
136 			topo->drawer_id = drawer->id;
137 			topo->book_id = book->id;
138 			topo->socket_id = socket->id;
139 			topo->core_id = rcore;
140 			topo->thread_id = lcpu + i;
141 			topo->dedicated = tl_core->d;
142 			cpumask_set_cpu(lcpu + i, &drawer->mask);
143 			cpumask_set_cpu(lcpu + i, &book->mask);
144 			cpumask_set_cpu(lcpu + i, &socket->mask);
145 			smp_cpu_set_polarization(lcpu + i, tl_core->pp);
146 		}
147 	}
148 }
149 
150 static void clear_masks(void)
151 {
152 	struct mask_info *info;
153 
154 	info = &socket_info;
155 	while (info) {
156 		cpumask_clear(&info->mask);
157 		info = info->next;
158 	}
159 	info = &book_info;
160 	while (info) {
161 		cpumask_clear(&info->mask);
162 		info = info->next;
163 	}
164 	info = &drawer_info;
165 	while (info) {
166 		cpumask_clear(&info->mask);
167 		info = info->next;
168 	}
169 }
170 
171 static union topology_entry *next_tle(union topology_entry *tle)
172 {
173 	if (!tle->nl)
174 		return (union topology_entry *)((struct topology_core *)tle + 1);
175 	return (union topology_entry *)((struct topology_container *)tle + 1);
176 }
177 
178 static void tl_to_masks(struct sysinfo_15_1_x *info)
179 {
180 	struct mask_info *socket = &socket_info;
181 	struct mask_info *book = &book_info;
182 	struct mask_info *drawer = &drawer_info;
183 	union topology_entry *tle, *end;
184 
185 	clear_masks();
186 	tle = info->tle;
187 	end = (union topology_entry *)((unsigned long)info + info->length);
188 	while (tle < end) {
189 		switch (tle->nl) {
190 		case 3:
191 			drawer = drawer->next;
192 			drawer->id = tle->container.id;
193 			break;
194 		case 2:
195 			book = book->next;
196 			book->id = tle->container.id;
197 			break;
198 		case 1:
199 			socket = socket->next;
200 			socket->id = tle->container.id;
201 			break;
202 		case 0:
203 			add_cpus_to_mask(&tle->cpu, drawer, book, socket);
204 			break;
205 		default:
206 			clear_masks();
207 			return;
208 		}
209 		tle = next_tle(tle);
210 	}
211 }
212 
213 static void topology_update_polarization_simple(void)
214 {
215 	int cpu;
216 
217 	for_each_possible_cpu(cpu)
218 		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
219 }
220 
221 static int ptf(unsigned long fc)
222 {
223 	int rc;
224 
225 	asm volatile(
226 		"	.insn	rre,0xb9a20000,%1,%1\n"
227 		"	ipm	%0\n"
228 		"	srl	%0,28\n"
229 		: "=d" (rc)
230 		: "d" (fc)  : "cc");
231 	return rc;
232 }
233 
234 int topology_set_cpu_management(int fc)
235 {
236 	int cpu, rc;
237 
238 	if (!MACHINE_HAS_TOPOLOGY)
239 		return -EOPNOTSUPP;
240 	if (fc)
241 		rc = ptf(PTF_VERTICAL);
242 	else
243 		rc = ptf(PTF_HORIZONTAL);
244 	if (rc)
245 		return -EBUSY;
246 	for_each_possible_cpu(cpu)
247 		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
248 	return rc;
249 }
250 
251 void update_cpu_masks(void)
252 {
253 	struct cpu_topology_s390 *topo, *topo_package, *topo_sibling;
254 	int cpu, sibling, pkg_first, smt_first, id;
255 
256 	for_each_possible_cpu(cpu) {
257 		topo = &cpu_topology[cpu];
258 		cpu_thread_map(&topo->thread_mask, cpu);
259 		cpu_group_map(&topo->core_mask, &socket_info, cpu);
260 		cpu_group_map(&topo->book_mask, &book_info, cpu);
261 		cpu_group_map(&topo->drawer_mask, &drawer_info, cpu);
262 		topo->booted_cores = 0;
263 		if (topology_mode != TOPOLOGY_MODE_HW) {
264 			id = topology_mode == TOPOLOGY_MODE_PACKAGE ? 0 : cpu;
265 			topo->thread_id = cpu;
266 			topo->core_id = cpu;
267 			topo->socket_id = id;
268 			topo->book_id = id;
269 			topo->drawer_id = id;
270 		}
271 	}
272 	for_each_online_cpu(cpu) {
273 		topo = &cpu_topology[cpu];
274 		pkg_first = cpumask_first(&topo->core_mask);
275 		topo_package = &cpu_topology[pkg_first];
276 		if (cpu == pkg_first) {
277 			for_each_cpu(sibling, &topo->core_mask) {
278 				topo_sibling = &cpu_topology[sibling];
279 				smt_first = cpumask_first(&topo_sibling->thread_mask);
280 				if (sibling == smt_first)
281 					topo_package->booted_cores++;
282 			}
283 		} else {
284 			topo->booted_cores = topo_package->booted_cores;
285 		}
286 	}
287 }
288 
289 void store_topology(struct sysinfo_15_1_x *info)
290 {
291 	stsi(info, 15, 1, topology_mnest_limit());
292 }
293 
294 static void __arch_update_dedicated_flag(void *arg)
295 {
296 	if (topology_cpu_dedicated(smp_processor_id()))
297 		set_cpu_flag(CIF_DEDICATED_CPU);
298 	else
299 		clear_cpu_flag(CIF_DEDICATED_CPU);
300 }
301 
302 static int __arch_update_cpu_topology(void)
303 {
304 	struct sysinfo_15_1_x *info = tl_info;
305 	int rc = 0;
306 
307 	mutex_lock(&smp_cpu_state_mutex);
308 	if (MACHINE_HAS_TOPOLOGY) {
309 		rc = 1;
310 		store_topology(info);
311 		tl_to_masks(info);
312 	}
313 	update_cpu_masks();
314 	if (!MACHINE_HAS_TOPOLOGY)
315 		topology_update_polarization_simple();
316 	mutex_unlock(&smp_cpu_state_mutex);
317 	return rc;
318 }
319 
320 int arch_update_cpu_topology(void)
321 {
322 	struct device *dev;
323 	int cpu, rc;
324 
325 	rc = __arch_update_cpu_topology();
326 	on_each_cpu(__arch_update_dedicated_flag, NULL, 0);
327 	for_each_online_cpu(cpu) {
328 		dev = get_cpu_device(cpu);
329 		if (dev)
330 			kobject_uevent(&dev->kobj, KOBJ_CHANGE);
331 	}
332 	return rc;
333 }
334 
335 static void topology_work_fn(struct work_struct *work)
336 {
337 	rebuild_sched_domains();
338 }
339 
340 void topology_schedule_update(void)
341 {
342 	schedule_work(&topology_work);
343 }
344 
345 static void topology_flush_work(void)
346 {
347 	flush_work(&topology_work);
348 }
349 
350 static void topology_timer_fn(struct timer_list *unused)
351 {
352 	if (ptf(PTF_CHECK))
353 		topology_schedule_update();
354 	set_topology_timer();
355 }
356 
357 static struct timer_list topology_timer;
358 
359 static atomic_t topology_poll = ATOMIC_INIT(0);
360 
361 static void set_topology_timer(void)
362 {
363 	if (atomic_add_unless(&topology_poll, -1, 0))
364 		mod_timer(&topology_timer, jiffies + msecs_to_jiffies(100));
365 	else
366 		mod_timer(&topology_timer, jiffies + msecs_to_jiffies(60 * MSEC_PER_SEC));
367 }
368 
369 void topology_expect_change(void)
370 {
371 	if (!MACHINE_HAS_TOPOLOGY)
372 		return;
373 	/* This is racy, but it doesn't matter since it is just a heuristic.
374 	 * Worst case is that we poll in a higher frequency for a bit longer.
375 	 */
376 	if (atomic_read(&topology_poll) > 60)
377 		return;
378 	atomic_add(60, &topology_poll);
379 	set_topology_timer();
380 }
381 
382 static int cpu_management;
383 
384 static ssize_t dispatching_show(struct device *dev,
385 				struct device_attribute *attr,
386 				char *buf)
387 {
388 	ssize_t count;
389 
390 	mutex_lock(&smp_cpu_state_mutex);
391 	count = sprintf(buf, "%d\n", cpu_management);
392 	mutex_unlock(&smp_cpu_state_mutex);
393 	return count;
394 }
395 
396 static ssize_t dispatching_store(struct device *dev,
397 				 struct device_attribute *attr,
398 				 const char *buf,
399 				 size_t count)
400 {
401 	int val, rc;
402 	char delim;
403 
404 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
405 		return -EINVAL;
406 	if (val != 0 && val != 1)
407 		return -EINVAL;
408 	rc = 0;
409 	get_online_cpus();
410 	mutex_lock(&smp_cpu_state_mutex);
411 	if (cpu_management == val)
412 		goto out;
413 	rc = topology_set_cpu_management(val);
414 	if (rc)
415 		goto out;
416 	cpu_management = val;
417 	topology_expect_change();
418 out:
419 	mutex_unlock(&smp_cpu_state_mutex);
420 	put_online_cpus();
421 	return rc ? rc : count;
422 }
423 static DEVICE_ATTR_RW(dispatching);
424 
425 static ssize_t cpu_polarization_show(struct device *dev,
426 				     struct device_attribute *attr, char *buf)
427 {
428 	int cpu = dev->id;
429 	ssize_t count;
430 
431 	mutex_lock(&smp_cpu_state_mutex);
432 	switch (smp_cpu_get_polarization(cpu)) {
433 	case POLARIZATION_HRZ:
434 		count = sprintf(buf, "horizontal\n");
435 		break;
436 	case POLARIZATION_VL:
437 		count = sprintf(buf, "vertical:low\n");
438 		break;
439 	case POLARIZATION_VM:
440 		count = sprintf(buf, "vertical:medium\n");
441 		break;
442 	case POLARIZATION_VH:
443 		count = sprintf(buf, "vertical:high\n");
444 		break;
445 	default:
446 		count = sprintf(buf, "unknown\n");
447 		break;
448 	}
449 	mutex_unlock(&smp_cpu_state_mutex);
450 	return count;
451 }
452 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
453 
454 static struct attribute *topology_cpu_attrs[] = {
455 	&dev_attr_polarization.attr,
456 	NULL,
457 };
458 
459 static struct attribute_group topology_cpu_attr_group = {
460 	.attrs = topology_cpu_attrs,
461 };
462 
463 static ssize_t cpu_dedicated_show(struct device *dev,
464 				  struct device_attribute *attr, char *buf)
465 {
466 	int cpu = dev->id;
467 	ssize_t count;
468 
469 	mutex_lock(&smp_cpu_state_mutex);
470 	count = sprintf(buf, "%d\n", topology_cpu_dedicated(cpu));
471 	mutex_unlock(&smp_cpu_state_mutex);
472 	return count;
473 }
474 static DEVICE_ATTR(dedicated, 0444, cpu_dedicated_show, NULL);
475 
476 static struct attribute *topology_extra_cpu_attrs[] = {
477 	&dev_attr_dedicated.attr,
478 	NULL,
479 };
480 
481 static struct attribute_group topology_extra_cpu_attr_group = {
482 	.attrs = topology_extra_cpu_attrs,
483 };
484 
485 int topology_cpu_init(struct cpu *cpu)
486 {
487 	int rc;
488 
489 	rc = sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
490 	if (rc || !MACHINE_HAS_TOPOLOGY)
491 		return rc;
492 	rc = sysfs_create_group(&cpu->dev.kobj, &topology_extra_cpu_attr_group);
493 	if (rc)
494 		sysfs_remove_group(&cpu->dev.kobj, &topology_cpu_attr_group);
495 	return rc;
496 }
497 
498 static const struct cpumask *cpu_thread_mask(int cpu)
499 {
500 	return &cpu_topology[cpu].thread_mask;
501 }
502 
503 
504 const struct cpumask *cpu_coregroup_mask(int cpu)
505 {
506 	return &cpu_topology[cpu].core_mask;
507 }
508 
509 static const struct cpumask *cpu_book_mask(int cpu)
510 {
511 	return &cpu_topology[cpu].book_mask;
512 }
513 
514 static const struct cpumask *cpu_drawer_mask(int cpu)
515 {
516 	return &cpu_topology[cpu].drawer_mask;
517 }
518 
519 static struct sched_domain_topology_level s390_topology[] = {
520 	{ cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
521 	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
522 	{ cpu_book_mask, SD_INIT_NAME(BOOK) },
523 	{ cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
524 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
525 	{ NULL, },
526 };
527 
528 static void __init alloc_masks(struct sysinfo_15_1_x *info,
529 			       struct mask_info *mask, int offset)
530 {
531 	int i, nr_masks;
532 
533 	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
534 	for (i = 0; i < info->mnest - offset; i++)
535 		nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
536 	nr_masks = max(nr_masks, 1);
537 	for (i = 0; i < nr_masks; i++) {
538 		mask->next = memblock_alloc(sizeof(*mask->next), 8);
539 		if (!mask->next)
540 			panic("%s: Failed to allocate %zu bytes align=0x%x\n",
541 			      __func__, sizeof(*mask->next), 8);
542 		mask = mask->next;
543 	}
544 }
545 
546 void __init topology_init_early(void)
547 {
548 	struct sysinfo_15_1_x *info;
549 
550 	set_sched_topology(s390_topology);
551 	if (topology_mode == TOPOLOGY_MODE_UNINITIALIZED) {
552 		if (MACHINE_HAS_TOPOLOGY)
553 			topology_mode = TOPOLOGY_MODE_HW;
554 		else
555 			topology_mode = TOPOLOGY_MODE_SINGLE;
556 	}
557 	if (!MACHINE_HAS_TOPOLOGY)
558 		goto out;
559 	tl_info = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
560 	if (!tl_info)
561 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
562 		      __func__, PAGE_SIZE, PAGE_SIZE);
563 	info = tl_info;
564 	store_topology(info);
565 	pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
566 		info->mag[0], info->mag[1], info->mag[2], info->mag[3],
567 		info->mag[4], info->mag[5], info->mnest);
568 	alloc_masks(info, &socket_info, 1);
569 	alloc_masks(info, &book_info, 2);
570 	alloc_masks(info, &drawer_info, 3);
571 out:
572 	__arch_update_cpu_topology();
573 	__arch_update_dedicated_flag(NULL);
574 }
575 
576 static inline int topology_get_mode(int enabled)
577 {
578 	if (!enabled)
579 		return TOPOLOGY_MODE_SINGLE;
580 	return MACHINE_HAS_TOPOLOGY ? TOPOLOGY_MODE_HW : TOPOLOGY_MODE_PACKAGE;
581 }
582 
583 static inline int topology_is_enabled(void)
584 {
585 	return topology_mode != TOPOLOGY_MODE_SINGLE;
586 }
587 
588 static int __init topology_setup(char *str)
589 {
590 	bool enabled;
591 	int rc;
592 
593 	rc = kstrtobool(str, &enabled);
594 	if (rc)
595 		return rc;
596 	topology_mode = topology_get_mode(enabled);
597 	return 0;
598 }
599 early_param("topology", topology_setup);
600 
601 static int topology_ctl_handler(struct ctl_table *ctl, int write,
602 				void *buffer, size_t *lenp, loff_t *ppos)
603 {
604 	int enabled = topology_is_enabled();
605 	int new_mode;
606 	int rc;
607 	struct ctl_table ctl_entry = {
608 		.procname	= ctl->procname,
609 		.data		= &enabled,
610 		.maxlen		= sizeof(int),
611 		.extra1		= SYSCTL_ZERO,
612 		.extra2		= SYSCTL_ONE,
613 	};
614 
615 	rc = proc_douintvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
616 	if (rc < 0 || !write)
617 		return rc;
618 
619 	mutex_lock(&smp_cpu_state_mutex);
620 	new_mode = topology_get_mode(enabled);
621 	if (topology_mode != new_mode) {
622 		topology_mode = new_mode;
623 		topology_schedule_update();
624 	}
625 	mutex_unlock(&smp_cpu_state_mutex);
626 	topology_flush_work();
627 
628 	return rc;
629 }
630 
631 static struct ctl_table topology_ctl_table[] = {
632 	{
633 		.procname	= "topology",
634 		.mode		= 0644,
635 		.proc_handler	= topology_ctl_handler,
636 	},
637 	{ },
638 };
639 
640 static struct ctl_table topology_dir_table[] = {
641 	{
642 		.procname	= "s390",
643 		.maxlen		= 0,
644 		.mode		= 0555,
645 		.child		= topology_ctl_table,
646 	},
647 	{ },
648 };
649 
650 static int __init topology_init(void)
651 {
652 	timer_setup(&topology_timer, topology_timer_fn, TIMER_DEFERRABLE);
653 	if (MACHINE_HAS_TOPOLOGY)
654 		set_topology_timer();
655 	else
656 		topology_update_polarization_simple();
657 	register_sysctl_table(topology_dir_table);
658 	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
659 }
660 device_initcall(topology_init);
661