xref: /openbmc/linux/arch/s390/kernel/topology.c (revision e5f586c763a079349398e2b0c7c271386193ac34)
1 /*
2  *    Copyright IBM Corp. 2007, 2011
3  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
4  */
5 
6 #define KMSG_COMPONENT "cpu"
7 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
8 
9 #include <linux/workqueue.h>
10 #include <linux/bootmem.h>
11 #include <linux/cpuset.h>
12 #include <linux/device.h>
13 #include <linux/export.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/sched/topology.h>
17 #include <linux/delay.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/cpu.h>
21 #include <linux/smp.h>
22 #include <linux/mm.h>
23 #include <linux/nodemask.h>
24 #include <linux/node.h>
25 #include <asm/sysinfo.h>
26 #include <asm/numa.h>
27 
28 #define PTF_HORIZONTAL	(0UL)
29 #define PTF_VERTICAL	(1UL)
30 #define PTF_CHECK	(2UL)
31 
32 struct mask_info {
33 	struct mask_info *next;
34 	unsigned char id;
35 	cpumask_t mask;
36 };
37 
38 static void set_topology_timer(void);
39 static void topology_work_fn(struct work_struct *work);
40 static struct sysinfo_15_1_x *tl_info;
41 
42 static DECLARE_WORK(topology_work, topology_work_fn);
43 
44 /*
45  * Socket/Book linked lists and cpu_topology updates are
46  * protected by "sched_domains_mutex".
47  */
48 static struct mask_info socket_info;
49 static struct mask_info book_info;
50 static struct mask_info drawer_info;
51 
52 struct cpu_topology_s390 cpu_topology[NR_CPUS];
53 EXPORT_SYMBOL_GPL(cpu_topology);
54 
55 cpumask_t cpus_with_topology;
56 
57 static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
58 {
59 	cpumask_t mask;
60 
61 	cpumask_copy(&mask, cpumask_of(cpu));
62 	if (!MACHINE_HAS_TOPOLOGY)
63 		return mask;
64 	for (; info; info = info->next) {
65 		if (cpumask_test_cpu(cpu, &info->mask))
66 			return info->mask;
67 	}
68 	return mask;
69 }
70 
71 static cpumask_t cpu_thread_map(unsigned int cpu)
72 {
73 	cpumask_t mask;
74 	int i;
75 
76 	cpumask_copy(&mask, cpumask_of(cpu));
77 	if (!MACHINE_HAS_TOPOLOGY)
78 		return mask;
79 	cpu -= cpu % (smp_cpu_mtid + 1);
80 	for (i = 0; i <= smp_cpu_mtid; i++)
81 		if (cpu_present(cpu + i))
82 			cpumask_set_cpu(cpu + i, &mask);
83 	return mask;
84 }
85 
86 static void add_cpus_to_mask(struct topology_core *tl_core,
87 			     struct mask_info *drawer,
88 			     struct mask_info *book,
89 			     struct mask_info *socket)
90 {
91 	struct cpu_topology_s390 *topo;
92 	unsigned int core;
93 
94 	for_each_set_bit(core, &tl_core->mask[0], TOPOLOGY_CORE_BITS) {
95 		unsigned int rcore;
96 		int lcpu, i;
97 
98 		rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
99 		lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
100 		if (lcpu < 0)
101 			continue;
102 		for (i = 0; i <= smp_cpu_mtid; i++) {
103 			topo = &cpu_topology[lcpu + i];
104 			topo->drawer_id = drawer->id;
105 			topo->book_id = book->id;
106 			topo->socket_id = socket->id;
107 			topo->core_id = rcore;
108 			topo->thread_id = lcpu + i;
109 			cpumask_set_cpu(lcpu + i, &drawer->mask);
110 			cpumask_set_cpu(lcpu + i, &book->mask);
111 			cpumask_set_cpu(lcpu + i, &socket->mask);
112 			cpumask_set_cpu(lcpu + i, &cpus_with_topology);
113 			smp_cpu_set_polarization(lcpu + i, tl_core->pp);
114 		}
115 	}
116 }
117 
118 static void clear_masks(void)
119 {
120 	struct mask_info *info;
121 
122 	info = &socket_info;
123 	while (info) {
124 		cpumask_clear(&info->mask);
125 		info = info->next;
126 	}
127 	info = &book_info;
128 	while (info) {
129 		cpumask_clear(&info->mask);
130 		info = info->next;
131 	}
132 	info = &drawer_info;
133 	while (info) {
134 		cpumask_clear(&info->mask);
135 		info = info->next;
136 	}
137 }
138 
139 static union topology_entry *next_tle(union topology_entry *tle)
140 {
141 	if (!tle->nl)
142 		return (union topology_entry *)((struct topology_core *)tle + 1);
143 	return (union topology_entry *)((struct topology_container *)tle + 1);
144 }
145 
146 static void tl_to_masks(struct sysinfo_15_1_x *info)
147 {
148 	struct mask_info *socket = &socket_info;
149 	struct mask_info *book = &book_info;
150 	struct mask_info *drawer = &drawer_info;
151 	union topology_entry *tle, *end;
152 
153 	clear_masks();
154 	tle = info->tle;
155 	end = (union topology_entry *)((unsigned long)info + info->length);
156 	while (tle < end) {
157 		switch (tle->nl) {
158 		case 3:
159 			drawer = drawer->next;
160 			drawer->id = tle->container.id;
161 			break;
162 		case 2:
163 			book = book->next;
164 			book->id = tle->container.id;
165 			break;
166 		case 1:
167 			socket = socket->next;
168 			socket->id = tle->container.id;
169 			break;
170 		case 0:
171 			add_cpus_to_mask(&tle->cpu, drawer, book, socket);
172 			break;
173 		default:
174 			clear_masks();
175 			return;
176 		}
177 		tle = next_tle(tle);
178 	}
179 }
180 
181 static void topology_update_polarization_simple(void)
182 {
183 	int cpu;
184 
185 	mutex_lock(&smp_cpu_state_mutex);
186 	for_each_possible_cpu(cpu)
187 		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
188 	mutex_unlock(&smp_cpu_state_mutex);
189 }
190 
191 static int ptf(unsigned long fc)
192 {
193 	int rc;
194 
195 	asm volatile(
196 		"	.insn	rre,0xb9a20000,%1,%1\n"
197 		"	ipm	%0\n"
198 		"	srl	%0,28\n"
199 		: "=d" (rc)
200 		: "d" (fc)  : "cc");
201 	return rc;
202 }
203 
204 int topology_set_cpu_management(int fc)
205 {
206 	int cpu, rc;
207 
208 	if (!MACHINE_HAS_TOPOLOGY)
209 		return -EOPNOTSUPP;
210 	if (fc)
211 		rc = ptf(PTF_VERTICAL);
212 	else
213 		rc = ptf(PTF_HORIZONTAL);
214 	if (rc)
215 		return -EBUSY;
216 	for_each_possible_cpu(cpu)
217 		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
218 	return rc;
219 }
220 
221 static void update_cpu_masks(void)
222 {
223 	struct cpu_topology_s390 *topo;
224 	int cpu;
225 
226 	for_each_possible_cpu(cpu) {
227 		topo = &cpu_topology[cpu];
228 		topo->thread_mask = cpu_thread_map(cpu);
229 		topo->core_mask = cpu_group_map(&socket_info, cpu);
230 		topo->book_mask = cpu_group_map(&book_info, cpu);
231 		topo->drawer_mask = cpu_group_map(&drawer_info, cpu);
232 		if (!MACHINE_HAS_TOPOLOGY) {
233 			topo->thread_id = cpu;
234 			topo->core_id = cpu;
235 			topo->socket_id = cpu;
236 			topo->book_id = cpu;
237 			topo->drawer_id = cpu;
238 			if (cpu_present(cpu))
239 				cpumask_set_cpu(cpu, &cpus_with_topology);
240 		}
241 	}
242 	numa_update_cpu_topology();
243 }
244 
245 void store_topology(struct sysinfo_15_1_x *info)
246 {
247 	stsi(info, 15, 1, min(topology_max_mnest, 4));
248 }
249 
250 static int __arch_update_cpu_topology(void)
251 {
252 	struct sysinfo_15_1_x *info = tl_info;
253 	int rc = 0;
254 
255 	cpumask_clear(&cpus_with_topology);
256 	if (MACHINE_HAS_TOPOLOGY) {
257 		rc = 1;
258 		store_topology(info);
259 		tl_to_masks(info);
260 	}
261 	update_cpu_masks();
262 	if (!MACHINE_HAS_TOPOLOGY)
263 		topology_update_polarization_simple();
264 	return rc;
265 }
266 
267 int arch_update_cpu_topology(void)
268 {
269 	struct device *dev;
270 	int cpu, rc;
271 
272 	rc = __arch_update_cpu_topology();
273 	for_each_online_cpu(cpu) {
274 		dev = get_cpu_device(cpu);
275 		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
276 	}
277 	return rc;
278 }
279 
280 static void topology_work_fn(struct work_struct *work)
281 {
282 	rebuild_sched_domains();
283 }
284 
285 void topology_schedule_update(void)
286 {
287 	schedule_work(&topology_work);
288 }
289 
290 static void topology_timer_fn(unsigned long ignored)
291 {
292 	if (ptf(PTF_CHECK))
293 		topology_schedule_update();
294 	set_topology_timer();
295 }
296 
297 static struct timer_list topology_timer =
298 	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
299 
300 static atomic_t topology_poll = ATOMIC_INIT(0);
301 
302 static void set_topology_timer(void)
303 {
304 	if (atomic_add_unless(&topology_poll, -1, 0))
305 		mod_timer(&topology_timer, jiffies + HZ / 10);
306 	else
307 		mod_timer(&topology_timer, jiffies + HZ * 60);
308 }
309 
310 void topology_expect_change(void)
311 {
312 	if (!MACHINE_HAS_TOPOLOGY)
313 		return;
314 	/* This is racy, but it doesn't matter since it is just a heuristic.
315 	 * Worst case is that we poll in a higher frequency for a bit longer.
316 	 */
317 	if (atomic_read(&topology_poll) > 60)
318 		return;
319 	atomic_add(60, &topology_poll);
320 	set_topology_timer();
321 }
322 
323 static int cpu_management;
324 
325 static ssize_t dispatching_show(struct device *dev,
326 				struct device_attribute *attr,
327 				char *buf)
328 {
329 	ssize_t count;
330 
331 	mutex_lock(&smp_cpu_state_mutex);
332 	count = sprintf(buf, "%d\n", cpu_management);
333 	mutex_unlock(&smp_cpu_state_mutex);
334 	return count;
335 }
336 
337 static ssize_t dispatching_store(struct device *dev,
338 				 struct device_attribute *attr,
339 				 const char *buf,
340 				 size_t count)
341 {
342 	int val, rc;
343 	char delim;
344 
345 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
346 		return -EINVAL;
347 	if (val != 0 && val != 1)
348 		return -EINVAL;
349 	rc = 0;
350 	get_online_cpus();
351 	mutex_lock(&smp_cpu_state_mutex);
352 	if (cpu_management == val)
353 		goto out;
354 	rc = topology_set_cpu_management(val);
355 	if (rc)
356 		goto out;
357 	cpu_management = val;
358 	topology_expect_change();
359 out:
360 	mutex_unlock(&smp_cpu_state_mutex);
361 	put_online_cpus();
362 	return rc ? rc : count;
363 }
364 static DEVICE_ATTR(dispatching, 0644, dispatching_show,
365 			 dispatching_store);
366 
367 static ssize_t cpu_polarization_show(struct device *dev,
368 				     struct device_attribute *attr, char *buf)
369 {
370 	int cpu = dev->id;
371 	ssize_t count;
372 
373 	mutex_lock(&smp_cpu_state_mutex);
374 	switch (smp_cpu_get_polarization(cpu)) {
375 	case POLARIZATION_HRZ:
376 		count = sprintf(buf, "horizontal\n");
377 		break;
378 	case POLARIZATION_VL:
379 		count = sprintf(buf, "vertical:low\n");
380 		break;
381 	case POLARIZATION_VM:
382 		count = sprintf(buf, "vertical:medium\n");
383 		break;
384 	case POLARIZATION_VH:
385 		count = sprintf(buf, "vertical:high\n");
386 		break;
387 	default:
388 		count = sprintf(buf, "unknown\n");
389 		break;
390 	}
391 	mutex_unlock(&smp_cpu_state_mutex);
392 	return count;
393 }
394 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
395 
396 static struct attribute *topology_cpu_attrs[] = {
397 	&dev_attr_polarization.attr,
398 	NULL,
399 };
400 
401 static struct attribute_group topology_cpu_attr_group = {
402 	.attrs = topology_cpu_attrs,
403 };
404 
405 int topology_cpu_init(struct cpu *cpu)
406 {
407 	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
408 }
409 
410 static const struct cpumask *cpu_thread_mask(int cpu)
411 {
412 	return &cpu_topology[cpu].thread_mask;
413 }
414 
415 
416 const struct cpumask *cpu_coregroup_mask(int cpu)
417 {
418 	return &cpu_topology[cpu].core_mask;
419 }
420 
421 static const struct cpumask *cpu_book_mask(int cpu)
422 {
423 	return &cpu_topology[cpu].book_mask;
424 }
425 
426 static const struct cpumask *cpu_drawer_mask(int cpu)
427 {
428 	return &cpu_topology[cpu].drawer_mask;
429 }
430 
431 static struct sched_domain_topology_level s390_topology[] = {
432 	{ cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
433 	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
434 	{ cpu_book_mask, SD_INIT_NAME(BOOK) },
435 	{ cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
436 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
437 	{ NULL, },
438 };
439 
440 static void __init alloc_masks(struct sysinfo_15_1_x *info,
441 			       struct mask_info *mask, int offset)
442 {
443 	int i, nr_masks;
444 
445 	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
446 	for (i = 0; i < info->mnest - offset; i++)
447 		nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
448 	nr_masks = max(nr_masks, 1);
449 	for (i = 0; i < nr_masks; i++) {
450 		mask->next = memblock_virt_alloc(sizeof(*mask->next), 8);
451 		mask = mask->next;
452 	}
453 }
454 
455 void __init topology_init_early(void)
456 {
457 	struct sysinfo_15_1_x *info;
458 
459 	set_sched_topology(s390_topology);
460 	if (!MACHINE_HAS_TOPOLOGY)
461 		goto out;
462 	tl_info = memblock_virt_alloc(PAGE_SIZE, PAGE_SIZE);
463 	info = tl_info;
464 	store_topology(info);
465 	pr_info("The CPU configuration topology of the machine is: %d %d %d %d %d %d / %d\n",
466 		info->mag[0], info->mag[1], info->mag[2], info->mag[3],
467 		info->mag[4], info->mag[5], info->mnest);
468 	alloc_masks(info, &socket_info, 1);
469 	alloc_masks(info, &book_info, 2);
470 	alloc_masks(info, &drawer_info, 3);
471 out:
472 	__arch_update_cpu_topology();
473 }
474 
475 static int __init topology_init(void)
476 {
477 	if (MACHINE_HAS_TOPOLOGY)
478 		set_topology_timer();
479 	else
480 		topology_update_polarization_simple();
481 	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
482 }
483 device_initcall(topology_init);
484