xref: /openbmc/linux/arch/s390/kernel/topology.c (revision 8684014d)
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/init.h>
17 #include <linux/delay.h>
18 #include <linux/cpu.h>
19 #include <linux/smp.h>
20 #include <linux/mm.h>
21 #include <asm/sysinfo.h>
22 
23 #define PTF_HORIZONTAL	(0UL)
24 #define PTF_VERTICAL	(1UL)
25 #define PTF_CHECK	(2UL)
26 
27 struct mask_info {
28 	struct mask_info *next;
29 	unsigned char id;
30 	cpumask_t mask;
31 };
32 
33 static void set_topology_timer(void);
34 static void topology_work_fn(struct work_struct *work);
35 static struct sysinfo_15_1_x *tl_info;
36 
37 static int topology_enabled = 1;
38 static DECLARE_WORK(topology_work, topology_work_fn);
39 
40 /* topology_lock protects the socket and book linked lists */
41 static DEFINE_SPINLOCK(topology_lock);
42 static struct mask_info socket_info;
43 static struct mask_info book_info;
44 
45 struct cpu_topology_s390 cpu_topology[NR_CPUS];
46 EXPORT_SYMBOL_GPL(cpu_topology);
47 
48 static cpumask_t cpu_group_map(struct mask_info *info, unsigned int cpu)
49 {
50 	cpumask_t mask;
51 
52 	cpumask_copy(&mask, cpumask_of(cpu));
53 	if (!topology_enabled || !MACHINE_HAS_TOPOLOGY)
54 		return mask;
55 	for (; info; info = info->next) {
56 		if (cpumask_test_cpu(cpu, &info->mask))
57 			return info->mask;
58 	}
59 	return mask;
60 }
61 
62 static struct mask_info *add_cpus_to_mask(struct topology_cpu *tl_cpu,
63 					  struct mask_info *book,
64 					  struct mask_info *socket,
65 					  int one_socket_per_cpu)
66 {
67 	unsigned int cpu;
68 
69 	for_each_set_bit(cpu, &tl_cpu->mask[0], TOPOLOGY_CPU_BITS) {
70 		unsigned int rcpu;
71 		int lcpu;
72 
73 		rcpu = TOPOLOGY_CPU_BITS - 1 - cpu + tl_cpu->origin;
74 		lcpu = smp_find_processor_id(rcpu);
75 		if (lcpu < 0)
76 			continue;
77 		cpumask_set_cpu(lcpu, &book->mask);
78 		cpu_topology[lcpu].book_id = book->id;
79 		cpumask_set_cpu(lcpu, &socket->mask);
80 		cpu_topology[lcpu].core_id = rcpu;
81 		if (one_socket_per_cpu) {
82 			cpu_topology[lcpu].socket_id = rcpu;
83 			socket = socket->next;
84 		} else {
85 			cpu_topology[lcpu].socket_id = socket->id;
86 		}
87 		smp_cpu_set_polarization(lcpu, tl_cpu->pp);
88 	}
89 	return socket;
90 }
91 
92 static void clear_masks(void)
93 {
94 	struct mask_info *info;
95 
96 	info = &socket_info;
97 	while (info) {
98 		cpumask_clear(&info->mask);
99 		info = info->next;
100 	}
101 	info = &book_info;
102 	while (info) {
103 		cpumask_clear(&info->mask);
104 		info = info->next;
105 	}
106 }
107 
108 static union topology_entry *next_tle(union topology_entry *tle)
109 {
110 	if (!tle->nl)
111 		return (union topology_entry *)((struct topology_cpu *)tle + 1);
112 	return (union topology_entry *)((struct topology_container *)tle + 1);
113 }
114 
115 static void __tl_to_masks_generic(struct sysinfo_15_1_x *info)
116 {
117 	struct mask_info *socket = &socket_info;
118 	struct mask_info *book = &book_info;
119 	union topology_entry *tle, *end;
120 
121 	tle = info->tle;
122 	end = (union topology_entry *)((unsigned long)info + info->length);
123 	while (tle < end) {
124 		switch (tle->nl) {
125 		case 2:
126 			book = book->next;
127 			book->id = tle->container.id;
128 			break;
129 		case 1:
130 			socket = socket->next;
131 			socket->id = tle->container.id;
132 			break;
133 		case 0:
134 			add_cpus_to_mask(&tle->cpu, book, socket, 0);
135 			break;
136 		default:
137 			clear_masks();
138 			return;
139 		}
140 		tle = next_tle(tle);
141 	}
142 }
143 
144 static void __tl_to_masks_z10(struct sysinfo_15_1_x *info)
145 {
146 	struct mask_info *socket = &socket_info;
147 	struct mask_info *book = &book_info;
148 	union topology_entry *tle, *end;
149 
150 	tle = info->tle;
151 	end = (union topology_entry *)((unsigned long)info + info->length);
152 	while (tle < end) {
153 		switch (tle->nl) {
154 		case 1:
155 			book = book->next;
156 			book->id = tle->container.id;
157 			break;
158 		case 0:
159 			socket = add_cpus_to_mask(&tle->cpu, book, socket, 1);
160 			break;
161 		default:
162 			clear_masks();
163 			return;
164 		}
165 		tle = next_tle(tle);
166 	}
167 }
168 
169 static void tl_to_masks(struct sysinfo_15_1_x *info)
170 {
171 	struct cpuid cpu_id;
172 
173 	spin_lock_irq(&topology_lock);
174 	get_cpu_id(&cpu_id);
175 	clear_masks();
176 	switch (cpu_id.machine) {
177 	case 0x2097:
178 	case 0x2098:
179 		__tl_to_masks_z10(info);
180 		break;
181 	default:
182 		__tl_to_masks_generic(info);
183 	}
184 	spin_unlock_irq(&topology_lock);
185 }
186 
187 static void topology_update_polarization_simple(void)
188 {
189 	int cpu;
190 
191 	mutex_lock(&smp_cpu_state_mutex);
192 	for_each_possible_cpu(cpu)
193 		smp_cpu_set_polarization(cpu, POLARIZATION_HRZ);
194 	mutex_unlock(&smp_cpu_state_mutex);
195 }
196 
197 static int ptf(unsigned long fc)
198 {
199 	int rc;
200 
201 	asm volatile(
202 		"	.insn	rre,0xb9a20000,%1,%1\n"
203 		"	ipm	%0\n"
204 		"	srl	%0,28\n"
205 		: "=d" (rc)
206 		: "d" (fc)  : "cc");
207 	return rc;
208 }
209 
210 int topology_set_cpu_management(int fc)
211 {
212 	int cpu, rc;
213 
214 	if (!MACHINE_HAS_TOPOLOGY)
215 		return -EOPNOTSUPP;
216 	if (fc)
217 		rc = ptf(PTF_VERTICAL);
218 	else
219 		rc = ptf(PTF_HORIZONTAL);
220 	if (rc)
221 		return -EBUSY;
222 	for_each_possible_cpu(cpu)
223 		smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
224 	return rc;
225 }
226 
227 static void update_cpu_masks(void)
228 {
229 	unsigned long flags;
230 	int cpu;
231 
232 	spin_lock_irqsave(&topology_lock, flags);
233 	for_each_possible_cpu(cpu) {
234 		cpu_topology[cpu].core_mask = cpu_group_map(&socket_info, cpu);
235 		cpu_topology[cpu].book_mask = cpu_group_map(&book_info, cpu);
236 		if (!MACHINE_HAS_TOPOLOGY) {
237 			cpu_topology[cpu].core_id = cpu;
238 			cpu_topology[cpu].socket_id = cpu;
239 			cpu_topology[cpu].book_id = cpu;
240 		}
241 	}
242 	spin_unlock_irqrestore(&topology_lock, flags);
243 }
244 
245 void store_topology(struct sysinfo_15_1_x *info)
246 {
247 	if (topology_max_mnest >= 3)
248 		stsi(info, 15, 1, 3);
249 	else
250 		stsi(info, 15, 1, 2);
251 }
252 
253 int arch_update_cpu_topology(void)
254 {
255 	struct sysinfo_15_1_x *info = tl_info;
256 	struct device *dev;
257 	int cpu;
258 
259 	if (!MACHINE_HAS_TOPOLOGY) {
260 		update_cpu_masks();
261 		topology_update_polarization_simple();
262 		return 0;
263 	}
264 	store_topology(info);
265 	tl_to_masks(info);
266 	update_cpu_masks();
267 	for_each_online_cpu(cpu) {
268 		dev = get_cpu_device(cpu);
269 		kobject_uevent(&dev->kobj, KOBJ_CHANGE);
270 	}
271 	return 1;
272 }
273 
274 static void topology_work_fn(struct work_struct *work)
275 {
276 	rebuild_sched_domains();
277 }
278 
279 void topology_schedule_update(void)
280 {
281 	schedule_work(&topology_work);
282 }
283 
284 static void topology_timer_fn(unsigned long ignored)
285 {
286 	if (ptf(PTF_CHECK))
287 		topology_schedule_update();
288 	set_topology_timer();
289 }
290 
291 static struct timer_list topology_timer =
292 	TIMER_DEFERRED_INITIALIZER(topology_timer_fn, 0, 0);
293 
294 static atomic_t topology_poll = ATOMIC_INIT(0);
295 
296 static void set_topology_timer(void)
297 {
298 	if (atomic_add_unless(&topology_poll, -1, 0))
299 		mod_timer(&topology_timer, jiffies + HZ / 10);
300 	else
301 		mod_timer(&topology_timer, jiffies + HZ * 60);
302 }
303 
304 void topology_expect_change(void)
305 {
306 	if (!MACHINE_HAS_TOPOLOGY)
307 		return;
308 	/* This is racy, but it doesn't matter since it is just a heuristic.
309 	 * Worst case is that we poll in a higher frequency for a bit longer.
310 	 */
311 	if (atomic_read(&topology_poll) > 60)
312 		return;
313 	atomic_add(60, &topology_poll);
314 	set_topology_timer();
315 }
316 
317 static int __init early_parse_topology(char *p)
318 {
319 	if (strncmp(p, "off", 3))
320 		return 0;
321 	topology_enabled = 0;
322 	return 0;
323 }
324 early_param("topology", early_parse_topology);
325 
326 static void __init alloc_masks(struct sysinfo_15_1_x *info,
327 			       struct mask_info *mask, int offset)
328 {
329 	int i, nr_masks;
330 
331 	nr_masks = info->mag[TOPOLOGY_NR_MAG - offset];
332 	for (i = 0; i < info->mnest - offset; i++)
333 		nr_masks *= info->mag[TOPOLOGY_NR_MAG - offset - 1 - i];
334 	nr_masks = max(nr_masks, 1);
335 	for (i = 0; i < nr_masks; i++) {
336 		mask->next = alloc_bootmem_align(
337 			roundup_pow_of_two(sizeof(struct mask_info)),
338 			roundup_pow_of_two(sizeof(struct mask_info)));
339 		mask = mask->next;
340 	}
341 }
342 
343 void __init s390_init_cpu_topology(void)
344 {
345 	struct sysinfo_15_1_x *info;
346 	int i;
347 
348 	if (!MACHINE_HAS_TOPOLOGY)
349 		return;
350 	tl_info = alloc_bootmem_pages(PAGE_SIZE);
351 	info = tl_info;
352 	store_topology(info);
353 	pr_info("The CPU configuration topology of the machine is:");
354 	for (i = 0; i < TOPOLOGY_NR_MAG; i++)
355 		printk(KERN_CONT " %d", info->mag[i]);
356 	printk(KERN_CONT " / %d\n", info->mnest);
357 	alloc_masks(info, &socket_info, 1);
358 	alloc_masks(info, &book_info, 2);
359 }
360 
361 static int cpu_management;
362 
363 static ssize_t dispatching_show(struct device *dev,
364 				struct device_attribute *attr,
365 				char *buf)
366 {
367 	ssize_t count;
368 
369 	mutex_lock(&smp_cpu_state_mutex);
370 	count = sprintf(buf, "%d\n", cpu_management);
371 	mutex_unlock(&smp_cpu_state_mutex);
372 	return count;
373 }
374 
375 static ssize_t dispatching_store(struct device *dev,
376 				 struct device_attribute *attr,
377 				 const char *buf,
378 				 size_t count)
379 {
380 	int val, rc;
381 	char delim;
382 
383 	if (sscanf(buf, "%d %c", &val, &delim) != 1)
384 		return -EINVAL;
385 	if (val != 0 && val != 1)
386 		return -EINVAL;
387 	rc = 0;
388 	get_online_cpus();
389 	mutex_lock(&smp_cpu_state_mutex);
390 	if (cpu_management == val)
391 		goto out;
392 	rc = topology_set_cpu_management(val);
393 	if (rc)
394 		goto out;
395 	cpu_management = val;
396 	topology_expect_change();
397 out:
398 	mutex_unlock(&smp_cpu_state_mutex);
399 	put_online_cpus();
400 	return rc ? rc : count;
401 }
402 static DEVICE_ATTR(dispatching, 0644, dispatching_show,
403 			 dispatching_store);
404 
405 static ssize_t cpu_polarization_show(struct device *dev,
406 				     struct device_attribute *attr, char *buf)
407 {
408 	int cpu = dev->id;
409 	ssize_t count;
410 
411 	mutex_lock(&smp_cpu_state_mutex);
412 	switch (smp_cpu_get_polarization(cpu)) {
413 	case POLARIZATION_HRZ:
414 		count = sprintf(buf, "horizontal\n");
415 		break;
416 	case POLARIZATION_VL:
417 		count = sprintf(buf, "vertical:low\n");
418 		break;
419 	case POLARIZATION_VM:
420 		count = sprintf(buf, "vertical:medium\n");
421 		break;
422 	case POLARIZATION_VH:
423 		count = sprintf(buf, "vertical:high\n");
424 		break;
425 	default:
426 		count = sprintf(buf, "unknown\n");
427 		break;
428 	}
429 	mutex_unlock(&smp_cpu_state_mutex);
430 	return count;
431 }
432 static DEVICE_ATTR(polarization, 0444, cpu_polarization_show, NULL);
433 
434 static struct attribute *topology_cpu_attrs[] = {
435 	&dev_attr_polarization.attr,
436 	NULL,
437 };
438 
439 static struct attribute_group topology_cpu_attr_group = {
440 	.attrs = topology_cpu_attrs,
441 };
442 
443 int topology_cpu_init(struct cpu *cpu)
444 {
445 	return sysfs_create_group(&cpu->dev.kobj, &topology_cpu_attr_group);
446 }
447 
448 const struct cpumask *cpu_coregroup_mask(int cpu)
449 {
450 	return &cpu_topology[cpu].core_mask;
451 }
452 
453 static const struct cpumask *cpu_book_mask(int cpu)
454 {
455 	return &cpu_topology[cpu].book_mask;
456 }
457 
458 static struct sched_domain_topology_level s390_topology[] = {
459 	{ cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
460 	{ cpu_book_mask, SD_INIT_NAME(BOOK) },
461 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
462 	{ NULL, },
463 };
464 
465 static int __init topology_init(void)
466 {
467 	if (MACHINE_HAS_TOPOLOGY)
468 		set_topology_timer();
469 	else
470 		topology_update_polarization_simple();
471 	return device_create_file(cpu_subsys.dev_root, &dev_attr_dispatching);
472 }
473 device_initcall(topology_init);
474 
475 static int __init early_topology_init(void)
476 {
477 	set_sched_topology(s390_topology);
478 	return 0;
479 }
480 early_initcall(early_topology_init);
481