xref: /openbmc/linux/arch/s390/kernel/topology.c (revision 80483c3a)
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/cpuset.h>
11 #include <linux/device.h>
12 #include <linux/export.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/delay.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/cpu.h>
19 #include <linux/smp.h>
20 #include <linux/mm.h>
21 #include <linux/nodemask.h>
22 #include <linux/node.h>
23 #include <asm/sysinfo.h>
24 #include <asm/numa.h>
25 
26 #define PTF_HORIZONTAL	(0UL)
27 #define PTF_VERTICAL	(1UL)
28 #define PTF_CHECK	(2UL)
29 
30 struct mask_info {
31 	struct mask_info *next;
32 	unsigned char id;
33 	cpumask_t mask;
34 };
35 
36 static void set_topology_timer(void);
37 static void topology_work_fn(struct work_struct *work);
38 static struct sysinfo_15_1_x *tl_info;
39 
40 static bool topology_enabled = true;
41 static DECLARE_WORK(topology_work, topology_work_fn);
42 
43 /*
44  * Socket/Book linked lists and per_cpu(cpu_topology) updates are
45  * protected by "sched_domains_mutex".
46  */
47 static struct mask_info socket_info;
48 static struct mask_info book_info;
49 static struct mask_info drawer_info;
50 
51 DEFINE_PER_CPU(struct cpu_topology_s390, cpu_topology);
52 EXPORT_PER_CPU_SYMBOL_GPL(cpu_topology);
53 
54 static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
55 {
56 	cpumask_t mask;
57 
58 	cpumask_copy(&mask, cpumask_of(cpu));
59 	if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
60 		return mask;
61 	for (; info; info = info->next) {
62 		if (cpumask_test_cpu(cpu, &info->mask))
63 			return info->mask;
64 	}
65 	return mask;
66 }
67 
68 static cpumask_t cpu_thread_map(unsigned int cpu)
69 {
70 	cpumask_t mask;
71 	int i;
72 
73 	cpumask_copy(&mask, cpumask_of(cpu));
74 	if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
75 		return mask;
76 	cpu -= cpu % (smp_cpu_mtid + 1);
77 	for (i = 0; i <= smp_cpu_mtid; i++)
78 		if (cpu_present(cpu + i))
79 			cpumask_set_cpu(cpu + i, &mask);
80 	return mask;
81 }
82 
83 static void add_cpus_to_mask(struct topology_core *tl_core,
84 			     struct mask_info *drawer,
85 			     struct mask_info *book,
86 			     struct mask_info *socket)
87 {
88 	struct cpu_topology_s390 *topo;
89 	unsigned int core;
90 
91 	for_each_set_bit(core, &tl_core->mask[0], TOPOLOGY_CORE_BITS) {
92 		unsigned int rcore;
93 		int lcpu, i;
94 
95 		rcore = TOPOLOGY_CORE_BITS - 1 - core + tl_core->origin;
96 		lcpu = smp_find_processor_id(rcore << smp_cpu_mt_shift);
97 		if (lcpu < 0)
98 			continue;
99 		for (i = 0; i <= smp_cpu_mtid; i++) {
100 			topo = &per_cpu(cpu_topology, lcpu + i);
101 			topo->drawer_id = drawer->id;
102 			topo->book_id = book->id;
103 			topo->socket_id = socket->id;
104 			topo->core_id = rcore;
105 			topo->thread_id = lcpu + i;
106 			cpumask_set_cpu(lcpu + i, &drawer->mask);
107 			cpumask_set_cpu(lcpu + i, &book->mask);
108 			cpumask_set_cpu(lcpu + i, &socket->mask);
109 			smp_cpu_set_polarization(lcpu + i, tl_core->pp);
110 		}
111 	}
112 }
113 
114 static void clear_masks(void)
115 {
116 	struct mask_info *info;
117 
118 	info = &socket_info;
119 	while (info) {
120 		cpumask_clear(&info->mask);
121 		info = info->next;
122 	}
123 	info = &book_info;
124 	while (info) {
125 		cpumask_clear(&info->mask);
126 		info = info->next;
127 	}
128 	info = &drawer_info;
129 	while (info) {
130 		cpumask_clear(&info->mask);
131 		info = info->next;
132 	}
133 }
134 
135 static union topology_entry *next_tle(union topology_entry *tle)
136 {
137 	if (!tle->nl)
138 		return (union topology_entry *)((struct topology_core *)tle + 1);
139 	return (union topology_entry *)((struct topology_container *)tle + 1);
140 }
141 
142 static void tl_to_masks(struct sysinfo_15_1_x *info)
143 {
144 	struct mask_info *socket = &socket_info;
145 	struct mask_info *book = &book_info;
146 	struct mask_info *drawer = &drawer_info;
147 	union topology_entry *tle, *end;
148 
149 	clear_masks();
150 	tle = info->tle;
151 	end = (union topology_entry *)((unsigned long)info + info->length);
152 	while (tle < end) {
153 		switch (tle->nl) {
154 		case 3:
155 			drawer = drawer->next;
156 			drawer->id = tle->container.id;
157 			break;
158 		case 2:
159 			book = book->next;
160 			book->id = tle->container.id;
161 			break;
162 		case 1:
163 			socket = socket->next;
164 			socket->id = tle->container.id;
165 			break;
166 		case 0:
167 			add_cpus_to_mask(&tle->cpu, drawer, book, socket);
168 			break;
169 		default:
170 			clear_masks();
171 			return;
172 		}
173 		tle = next_tle(tle);
174 	}
175 }
176 
177 static void topology_update_polarization_simple(void)
178 {
179 	int cpu;
180 
181 	mutex_lock(&smp_cpu_state_mutex);
182 	for_each_possible_cpu(cpu)
183 		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
184 	mutex_unlock(&smp_cpu_state_mutex);
185 }
186 
187 static int ptf(unsigned long fc)
188 {
189 	int rc;
190 
191 	asm volatile(
192 		"	.insn	rre,0xb9a20000,%1,%1\n"
193 		"	ipm	%0\n"
194 		"	srl	%0,28\n"
195 		: "=d" (rc)
196 		: "d" (fc)  : "cc");
197 	return rc;
198 }
199 
200 int topology_set_cpu_management(int fc)
201 {
202 	int cpu, rc;
203 
204 	if (!MACHINE_HAS_TOPOLOGY)
205 		return -EOPNOTSUPP;
206 	if (fc)
207 		rc = ptf(PTF_VERTICAL);
208 	else
209 		rc = ptf(PTF_HORIZONTAL);
210 	if (rc)
211 		return -EBUSY;
212 	for_each_possible_cpu(cpu)
213 		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
214 	return rc;
215 }
216 
217 static void update_cpu_masks(void)
218 {
219 	struct cpu_topology_s390 *topo;
220 	int cpu;
221 
222 	for_each_possible_cpu(cpu) {
223 		topo = &per_cpu(cpu_topology, cpu);
224 		topo->thread_mask = cpu_thread_map(cpu);
225 		topo->core_mask = cpu_group_map(&socket_info, cpu);
226 		topo->book_mask = cpu_group_map(&book_info, cpu);
227 		topo->drawer_mask = cpu_group_map(&drawer_info, cpu);
228 		if (!MACHINE_HAS_TOPOLOGY) {
229 			topo->thread_id = cpu;
230 			topo->core_id = cpu;
231 			topo->socket_id = cpu;
232 			topo->book_id = cpu;
233 			topo->drawer_id = cpu;
234 		}
235 	}
236 	numa_update_cpu_topology();
237 }
238 
239 void store_topology(struct sysinfo_15_1_x *info)
240 {
241 	stsi(info, 15, 1, min(topology_max_mnest, 4));
242 }
243 
244 int arch_update_cpu_topology(void)
245 {
246 	struct sysinfo_15_1_x *info = tl_info;
247 	struct device *dev;
248 	int cpu, rc = 0;
249 
250 	if (MACHINE_HAS_TOPOLOGY) {
251 		rc = 1;
252 		store_topology(info);
253 		tl_to_masks(info);
254 	}
255 	update_cpu_masks();
256 	if (!MACHINE_HAS_TOPOLOGY)
257 		topology_update_polarization_simple();
258 	for_each_online_cpu(cpu) {
259 		dev = get_cpu_device(cpu);
260 		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
261 	}
262 	return rc;
263 }
264 
265 static void topology_work_fn(struct work_struct *work)
266 {
267 	rebuild_sched_domains();
268 }
269 
270 void topology_schedule_update(void)
271 {
272 	schedule_work(&topology_work);
273 }
274 
275 static void topology_timer_fn(unsigned long ignored)
276 {
277 	if (ptf(PTF_CHECK))
278 		topology_schedule_update();
279 	set_topology_timer();
280 }
281 
282 static struct timer_list topology_timer =
283 	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
284 
285 static atomic_t topology_poll = ATOMIC_INIT(0);
286 
287 static void set_topology_timer(void)
288 {
289 	if (atomic_add_unless(&topology_poll, -1, 0))
290 		mod_timer(&topology_timer, jiffies + HZ / 10);
291 	else
292 		mod_timer(&topology_timer, jiffies + HZ * 60);
293 }
294 
295 void topology_expect_change(void)
296 {
297 	if (!MACHINE_HAS_TOPOLOGY)
298 		return;
299 	/* This is racy, but it doesn't matter since it is just a heuristic.
300 	 * Worst case is that we poll in a higher frequency for a bit longer.
301 	 */
302 	if (atomic_read(&topology_poll) > 60)
303 		return;
304 	atomic_add(60, &topology_poll);
305 	set_topology_timer();
306 }
307 
308 static int cpu_management;
309 
310 static ssize_t dispatching_show(struct device *dev,
311 				struct device_attribute *attr,
312 				char *buf)
313 {
314 	ssize_t count;
315 
316 	mutex_lock(&smp_cpu_state_mutex);
317 	count = sprintf(buf, "%d\n", cpu_management);
318 	mutex_unlock(&smp_cpu_state_mutex);
319 	return count;
320 }
321 
322 static ssize_t dispatching_store(struct device *dev,
323 				 struct device_attribute *attr,
324 				 const char *buf,
325 				 size_t count)
326 {
327 	int val, rc;
328 	char delim;
329 
330 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
331 		return -EINVAL;
332 	if (val != 0 && val != 1)
333 		return -EINVAL;
334 	rc = 0;
335 	get_online_cpus();
336 	mutex_lock(&smp_cpu_state_mutex);
337 	if (cpu_management == val)
338 		goto out;
339 	rc = topology_set_cpu_management(val);
340 	if (rc)
341 		goto out;
342 	cpu_management = val;
343 	topology_expect_change();
344 out:
345 	mutex_unlock(&smp_cpu_state_mutex);
346 	put_online_cpus();
347 	return rc ? rc : count;
348 }
349 static DEVICE_ATTR(dispatching, 0644, dispatching_show,
350 			 dispatching_store);
351 
352 static ssize_t cpu_polarization_show(struct device *dev,
353 				     struct device_attribute *attr, char *buf)
354 {
355 	int cpu = dev->id;
356 	ssize_t count;
357 
358 	mutex_lock(&smp_cpu_state_mutex);
359 	switch (smp_cpu_get_polarization(cpu)) {
360 	case POLARIZATION_HRZ:
361 		count = sprintf(buf, "horizontal\n");
362 		break;
363 	case POLARIZATION_VL:
364 		count = sprintf(buf, "vertical:low\n");
365 		break;
366 	case POLARIZATION_VM:
367 		count = sprintf(buf, "vertical:medium\n");
368 		break;
369 	case POLARIZATION_VH:
370 		count = sprintf(buf, "vertical:high\n");
371 		break;
372 	default:
373 		count = sprintf(buf, "unknown\n");
374 		break;
375 	}
376 	mutex_unlock(&smp_cpu_state_mutex);
377 	return count;
378 }
379 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
380 
381 static struct attribute *topology_cpu_attrs[] = {
382 	&dev_attr_polarization.attr,
383 	NULL,
384 };
385 
386 static struct attribute_group topology_cpu_attr_group = {
387 	.attrs = topology_cpu_attrs,
388 };
389 
390 int topology_cpu_init(struct cpu *cpu)
391 {
392 	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
393 }
394 
395 static const struct cpumask *cpu_thread_mask(int cpu)
396 {
397 	return &per_cpu(cpu_topology, cpu).thread_mask;
398 }
399 
400 
401 const struct cpumask *cpu_coregroup_mask(int cpu)
402 {
403 	return &per_cpu(cpu_topology, cpu).core_mask;
404 }
405 
406 static const struct cpumask *cpu_book_mask(int cpu)
407 {
408 	return &per_cpu(cpu_topology, cpu).book_mask;
409 }
410 
411 static const struct cpumask *cpu_drawer_mask(int cpu)
412 {
413 	return &per_cpu(cpu_topology, cpu).drawer_mask;
414 }
415 
416 static int __init early_parse_topology(char *p)
417 {
418 	return kstrtobool(p, &topology_enabled);
419 }
420 early_param("topology", early_parse_topology);
421 
422 static struct sched_domain_topology_level s390_topology[] = {
423 	{ cpu_thread_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
424 	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
425 	{ cpu_book_mask, SD_INIT_NAME(BOOK) },
426 	{ cpu_drawer_mask, SD_INIT_NAME(DRAWER) },
427 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
428 	{ NULL, },
429 };
430 
431 static void __init alloc_masks(struct sysinfo_15_1_x *info,
432 			       struct mask_info *mask, int offset)
433 {
434 	int i, nr_masks;
435 
436 	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
437 	for (i = 0; i < info->mnest - offset; i++)
438 		nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
439 	nr_masks = max(nr_masks, 1);
440 	for (i = 0; i < nr_masks; i++) {
441 		mask->next = kzalloc(sizeof(*mask->next), GFP_KERNEL);
442 		mask = mask->next;
443 	}
444 }
445 
446 static int __init s390_topology_init(void)
447 {
448 	struct sysinfo_15_1_x *info;
449 	int i;
450 
451 	if (!MACHINE_HAS_TOPOLOGY)
452 		return 0;
453 	tl_info = (struct sysinfo_15_1_x *)__get_free_page(GFP_KERNEL);
454 	info = tl_info;
455 	store_topology(info);
456 	pr_info("The CPU configuration topology of the machine is:");
457 	for (i = 0; i < TOPOLOGY_NR_MAG; i++)
458 		printk(KERN_CONT " %d", info->mag[i]);
459 	printk(KERN_CONT " / %d\n", info->mnest);
460 	alloc_masks(info, &socket_info, 1);
461 	alloc_masks(info, &book_info, 2);
462 	alloc_masks(info, &drawer_info, 3);
463 	set_sched_topology(s390_topology);
464 	return 0;
465 }
466 early_initcall(s390_topology_init);
467 
468 static int __init topology_init(void)
469 {
470 	if (MACHINE_HAS_TOPOLOGY)
471 		set_topology_timer();
472 	else
473 		topology_update_polarization_simple();
474 	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
475 }
476 device_initcall(topology_init);
477