Merge branch 'topic/nhlt' into for-next
[linux-2.6-microblaze.git] / drivers / base / cpu.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * CPU subsystem support
4  */
5
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/sched.h>
10 #include <linux/cpu.h>
11 #include <linux/topology.h>
12 #include <linux/device.h>
13 #include <linux/node.h>
14 #include <linux/gfp.h>
15 #include <linux/slab.h>
16 #include <linux/percpu.h>
17 #include <linux/acpi.h>
18 #include <linux/of.h>
19 #include <linux/cpufeature.h>
20 #include <linux/tick.h>
21 #include <linux/pm_qos.h>
22 #include <linux/sched/isolation.h>
23
24 #include "base.h"
25
26 static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
27
28 static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
29 {
30         /* ACPI style match is the only one that may succeed. */
31         if (acpi_driver_match_device(dev, drv))
32                 return 1;
33
34         return 0;
35 }
36
37 #ifdef CONFIG_HOTPLUG_CPU
38 static void change_cpu_under_node(struct cpu *cpu,
39                         unsigned int from_nid, unsigned int to_nid)
40 {
41         int cpuid = cpu->dev.id;
42         unregister_cpu_under_node(cpuid, from_nid);
43         register_cpu_under_node(cpuid, to_nid);
44         cpu->node_id = to_nid;
45 }
46
47 static int cpu_subsys_online(struct device *dev)
48 {
49         struct cpu *cpu = container_of(dev, struct cpu, dev);
50         int cpuid = dev->id;
51         int from_nid, to_nid;
52         int ret;
53
54         from_nid = cpu_to_node(cpuid);
55         if (from_nid == NUMA_NO_NODE)
56                 return -ENODEV;
57
58         ret = cpu_device_up(dev);
59         /*
60          * When hot adding memory to memoryless node and enabling a cpu
61          * on the node, node number of the cpu may internally change.
62          */
63         to_nid = cpu_to_node(cpuid);
64         if (from_nid != to_nid)
65                 change_cpu_under_node(cpu, from_nid, to_nid);
66
67         return ret;
68 }
69
70 static int cpu_subsys_offline(struct device *dev)
71 {
72         return cpu_device_down(dev);
73 }
74
75 void unregister_cpu(struct cpu *cpu)
76 {
77         int logical_cpu = cpu->dev.id;
78
79         unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
80
81         device_unregister(&cpu->dev);
82         per_cpu(cpu_sys_devices, logical_cpu) = NULL;
83         return;
84 }
85
86 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
87 static ssize_t cpu_probe_store(struct device *dev,
88                                struct device_attribute *attr,
89                                const char *buf,
90                                size_t count)
91 {
92         ssize_t cnt;
93         int ret;
94
95         ret = lock_device_hotplug_sysfs();
96         if (ret)
97                 return ret;
98
99         cnt = arch_cpu_probe(buf, count);
100
101         unlock_device_hotplug();
102         return cnt;
103 }
104
105 static ssize_t cpu_release_store(struct device *dev,
106                                  struct device_attribute *attr,
107                                  const char *buf,
108                                  size_t count)
109 {
110         ssize_t cnt;
111         int ret;
112
113         ret = lock_device_hotplug_sysfs();
114         if (ret)
115                 return ret;
116
117         cnt = arch_cpu_release(buf, count);
118
119         unlock_device_hotplug();
120         return cnt;
121 }
122
123 static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
124 static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
125 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
126 #endif /* CONFIG_HOTPLUG_CPU */
127
128 struct bus_type cpu_subsys = {
129         .name = "cpu",
130         .dev_name = "cpu",
131         .match = cpu_subsys_match,
132 #ifdef CONFIG_HOTPLUG_CPU
133         .online = cpu_subsys_online,
134         .offline = cpu_subsys_offline,
135 #endif
136 };
137 EXPORT_SYMBOL_GPL(cpu_subsys);
138
139 #ifdef CONFIG_KEXEC
140 #include <linux/kexec.h>
141
142 static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr,
143                                 char *buf)
144 {
145         struct cpu *cpu = container_of(dev, struct cpu, dev);
146         ssize_t rc;
147         unsigned long long addr;
148         int cpunum;
149
150         cpunum = cpu->dev.id;
151
152         /*
153          * Might be reading other cpu's data based on which cpu read thread
154          * has been scheduled. But cpu data (memory) is allocated once during
155          * boot up and this data does not change there after. Hence this
156          * operation should be safe. No locking required.
157          */
158         addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
159         rc = sprintf(buf, "%Lx\n", addr);
160         return rc;
161 }
162 static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
163
164 static ssize_t show_crash_notes_size(struct device *dev,
165                                      struct device_attribute *attr,
166                                      char *buf)
167 {
168         ssize_t rc;
169
170         rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
171         return rc;
172 }
173 static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
174
175 static struct attribute *crash_note_cpu_attrs[] = {
176         &dev_attr_crash_notes.attr,
177         &dev_attr_crash_notes_size.attr,
178         NULL
179 };
180
181 static struct attribute_group crash_note_cpu_attr_group = {
182         .attrs = crash_note_cpu_attrs,
183 };
184 #endif
185
186 static const struct attribute_group *common_cpu_attr_groups[] = {
187 #ifdef CONFIG_KEXEC
188         &crash_note_cpu_attr_group,
189 #endif
190         NULL
191 };
192
193 static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
194 #ifdef CONFIG_KEXEC
195         &crash_note_cpu_attr_group,
196 #endif
197         NULL
198 };
199
200 /*
201  * Print cpu online, possible, present, and system maps
202  */
203
204 struct cpu_attr {
205         struct device_attribute attr;
206         const struct cpumask *const map;
207 };
208
209 static ssize_t show_cpus_attr(struct device *dev,
210                               struct device_attribute *attr,
211                               char *buf)
212 {
213         struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
214
215         return cpumap_print_to_pagebuf(true, buf, ca->map);
216 }
217
218 #define _CPU_ATTR(name, map) \
219         { __ATTR(name, 0444, show_cpus_attr, NULL), map }
220
221 /* Keep in sync with cpu_subsys_attrs */
222 static struct cpu_attr cpu_attrs[] = {
223         _CPU_ATTR(online, &__cpu_online_mask),
224         _CPU_ATTR(possible, &__cpu_possible_mask),
225         _CPU_ATTR(present, &__cpu_present_mask),
226 };
227
228 /*
229  * Print values for NR_CPUS and offlined cpus
230  */
231 static ssize_t print_cpus_kernel_max(struct device *dev,
232                                      struct device_attribute *attr, char *buf)
233 {
234         return sprintf(buf, "%d\n", NR_CPUS - 1);
235 }
236 static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
237
238 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
239 unsigned int total_cpus;
240
241 static ssize_t print_cpus_offline(struct device *dev,
242                                   struct device_attribute *attr, char *buf)
243 {
244         int n = 0, len = PAGE_SIZE-2;
245         cpumask_var_t offline;
246
247         /* display offline cpus < nr_cpu_ids */
248         if (!alloc_cpumask_var(&offline, GFP_KERNEL))
249                 return -ENOMEM;
250         cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
251         n = scnprintf(buf, len, "%*pbl", cpumask_pr_args(offline));
252         free_cpumask_var(offline);
253
254         /* display offline cpus >= nr_cpu_ids */
255         if (total_cpus && nr_cpu_ids < total_cpus) {
256                 if (n && n < len)
257                         buf[n++] = ',';
258
259                 if (nr_cpu_ids == total_cpus-1)
260                         n += scnprintf(&buf[n], len - n, "%u", nr_cpu_ids);
261                 else
262                         n += scnprintf(&buf[n], len - n, "%u-%d",
263                                                       nr_cpu_ids, total_cpus-1);
264         }
265
266         n += scnprintf(&buf[n], len - n, "\n");
267         return n;
268 }
269 static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
270
271 static ssize_t print_cpus_isolated(struct device *dev,
272                                   struct device_attribute *attr, char *buf)
273 {
274         int n;
275         cpumask_var_t isolated;
276
277         if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
278                 return -ENOMEM;
279
280         cpumask_andnot(isolated, cpu_possible_mask,
281                        housekeeping_cpumask(HK_FLAG_DOMAIN));
282         n = sprintf(buf, "%*pbl\n", cpumask_pr_args(isolated));
283
284         free_cpumask_var(isolated);
285
286         return n;
287 }
288 static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
289
290 #ifdef CONFIG_NO_HZ_FULL
291 static ssize_t print_cpus_nohz_full(struct device *dev,
292                                   struct device_attribute *attr, char *buf)
293 {
294         return sprintf(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
295 }
296 static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
297 #endif
298
299 static void cpu_device_release(struct device *dev)
300 {
301         /*
302          * This is an empty function to prevent the driver core from spitting a
303          * warning at us.  Yes, I know this is directly opposite of what the
304          * documentation for the driver core and kobjects say, and the author
305          * of this code has already been publically ridiculed for doing
306          * something as foolish as this.  However, at this point in time, it is
307          * the only way to handle the issue of statically allocated cpu
308          * devices.  The different architectures will have their cpu device
309          * code reworked to properly handle this in the near future, so this
310          * function will then be changed to correctly free up the memory held
311          * by the cpu device.
312          *
313          * Never copy this way of doing things, or you too will be made fun of
314          * on the linux-kernel list, you have been warned.
315          */
316 }
317
318 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
319 static ssize_t print_cpu_modalias(struct device *dev,
320                                   struct device_attribute *attr,
321                                   char *buf)
322 {
323         ssize_t n;
324         u32 i;
325
326         n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
327                     CPU_FEATURE_TYPEVAL);
328
329         for (i = 0; i < MAX_CPU_FEATURES; i++)
330                 if (cpu_have_feature(i)) {
331                         if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
332                                 WARN(1, "CPU features overflow page\n");
333                                 break;
334                         }
335                         n += sprintf(&buf[n], ",%04X", i);
336                 }
337         buf[n++] = '\n';
338         return n;
339 }
340
341 static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
342 {
343         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
344         if (buf) {
345                 print_cpu_modalias(NULL, NULL, buf);
346                 add_uevent_var(env, "MODALIAS=%s", buf);
347                 kfree(buf);
348         }
349         return 0;
350 }
351 #endif
352
353 /*
354  * register_cpu - Setup a sysfs device for a CPU.
355  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
356  *        sysfs for this CPU.
357  * @num - CPU number to use when creating the device.
358  *
359  * Initialize and register the CPU device.
360  */
361 int register_cpu(struct cpu *cpu, int num)
362 {
363         int error;
364
365         cpu->node_id = cpu_to_node(num);
366         memset(&cpu->dev, 0x00, sizeof(struct device));
367         cpu->dev.id = num;
368         cpu->dev.bus = &cpu_subsys;
369         cpu->dev.release = cpu_device_release;
370         cpu->dev.offline_disabled = !cpu->hotpluggable;
371         cpu->dev.offline = !cpu_online(num);
372         cpu->dev.of_node = of_get_cpu_node(num, NULL);
373 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
374         cpu->dev.bus->uevent = cpu_uevent;
375 #endif
376         cpu->dev.groups = common_cpu_attr_groups;
377         if (cpu->hotpluggable)
378                 cpu->dev.groups = hotplugable_cpu_attr_groups;
379         error = device_register(&cpu->dev);
380         if (error) {
381                 put_device(&cpu->dev);
382                 return error;
383         }
384
385         per_cpu(cpu_sys_devices, num) = &cpu->dev;
386         register_cpu_under_node(num, cpu_to_node(num));
387         dev_pm_qos_expose_latency_limit(&cpu->dev,
388                                         PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
389
390         return 0;
391 }
392
393 struct device *get_cpu_device(unsigned cpu)
394 {
395         if (cpu < nr_cpu_ids && cpu_possible(cpu))
396                 return per_cpu(cpu_sys_devices, cpu);
397         else
398                 return NULL;
399 }
400 EXPORT_SYMBOL_GPL(get_cpu_device);
401
402 static void device_create_release(struct device *dev)
403 {
404         kfree(dev);
405 }
406
407 __printf(4, 0)
408 static struct device *
409 __cpu_device_create(struct device *parent, void *drvdata,
410                     const struct attribute_group **groups,
411                     const char *fmt, va_list args)
412 {
413         struct device *dev = NULL;
414         int retval = -ENODEV;
415
416         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
417         if (!dev) {
418                 retval = -ENOMEM;
419                 goto error;
420         }
421
422         device_initialize(dev);
423         dev->parent = parent;
424         dev->groups = groups;
425         dev->release = device_create_release;
426         device_set_pm_not_required(dev);
427         dev_set_drvdata(dev, drvdata);
428
429         retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
430         if (retval)
431                 goto error;
432
433         retval = device_add(dev);
434         if (retval)
435                 goto error;
436
437         return dev;
438
439 error:
440         put_device(dev);
441         return ERR_PTR(retval);
442 }
443
444 struct device *cpu_device_create(struct device *parent, void *drvdata,
445                                  const struct attribute_group **groups,
446                                  const char *fmt, ...)
447 {
448         va_list vargs;
449         struct device *dev;
450
451         va_start(vargs, fmt);
452         dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
453         va_end(vargs);
454         return dev;
455 }
456 EXPORT_SYMBOL_GPL(cpu_device_create);
457
458 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
459 static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
460 #endif
461
462 static struct attribute *cpu_root_attrs[] = {
463 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
464         &dev_attr_probe.attr,
465         &dev_attr_release.attr,
466 #endif
467         &cpu_attrs[0].attr.attr,
468         &cpu_attrs[1].attr.attr,
469         &cpu_attrs[2].attr.attr,
470         &dev_attr_kernel_max.attr,
471         &dev_attr_offline.attr,
472         &dev_attr_isolated.attr,
473 #ifdef CONFIG_NO_HZ_FULL
474         &dev_attr_nohz_full.attr,
475 #endif
476 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
477         &dev_attr_modalias.attr,
478 #endif
479         NULL
480 };
481
482 static struct attribute_group cpu_root_attr_group = {
483         .attrs = cpu_root_attrs,
484 };
485
486 static const struct attribute_group *cpu_root_attr_groups[] = {
487         &cpu_root_attr_group,
488         NULL,
489 };
490
491 bool cpu_is_hotpluggable(unsigned cpu)
492 {
493         struct device *dev = get_cpu_device(cpu);
494         return dev && container_of(dev, struct cpu, dev)->hotpluggable;
495 }
496 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
497
498 #ifdef CONFIG_GENERIC_CPU_DEVICES
499 static DEFINE_PER_CPU(struct cpu, cpu_devices);
500 #endif
501
502 static void __init cpu_dev_register_generic(void)
503 {
504 #ifdef CONFIG_GENERIC_CPU_DEVICES
505         int i;
506
507         for_each_possible_cpu(i) {
508                 if (register_cpu(&per_cpu(cpu_devices, i), i))
509                         panic("Failed to register CPU device");
510         }
511 #endif
512 }
513
514 #ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
515
516 ssize_t __weak cpu_show_meltdown(struct device *dev,
517                                  struct device_attribute *attr, char *buf)
518 {
519         return sprintf(buf, "Not affected\n");
520 }
521
522 ssize_t __weak cpu_show_spectre_v1(struct device *dev,
523                                    struct device_attribute *attr, char *buf)
524 {
525         return sprintf(buf, "Not affected\n");
526 }
527
528 ssize_t __weak cpu_show_spectre_v2(struct device *dev,
529                                    struct device_attribute *attr, char *buf)
530 {
531         return sprintf(buf, "Not affected\n");
532 }
533
534 ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
535                                           struct device_attribute *attr, char *buf)
536 {
537         return sprintf(buf, "Not affected\n");
538 }
539
540 ssize_t __weak cpu_show_l1tf(struct device *dev,
541                              struct device_attribute *attr, char *buf)
542 {
543         return sprintf(buf, "Not affected\n");
544 }
545
546 ssize_t __weak cpu_show_mds(struct device *dev,
547                             struct device_attribute *attr, char *buf)
548 {
549         return sprintf(buf, "Not affected\n");
550 }
551
552 ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
553                                         struct device_attribute *attr,
554                                         char *buf)
555 {
556         return sprintf(buf, "Not affected\n");
557 }
558
559 ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
560                             struct device_attribute *attr, char *buf)
561 {
562         return sprintf(buf, "Not affected\n");
563 }
564
565 static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
566 static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
567 static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
568 static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
569 static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
570 static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
571 static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
572 static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
573
574 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
575         &dev_attr_meltdown.attr,
576         &dev_attr_spectre_v1.attr,
577         &dev_attr_spectre_v2.attr,
578         &dev_attr_spec_store_bypass.attr,
579         &dev_attr_l1tf.attr,
580         &dev_attr_mds.attr,
581         &dev_attr_tsx_async_abort.attr,
582         &dev_attr_itlb_multihit.attr,
583         NULL
584 };
585
586 static const struct attribute_group cpu_root_vulnerabilities_group = {
587         .name  = "vulnerabilities",
588         .attrs = cpu_root_vulnerabilities_attrs,
589 };
590
591 static void __init cpu_register_vulnerabilities(void)
592 {
593         if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
594                                &cpu_root_vulnerabilities_group))
595                 pr_err("Unable to register CPU vulnerabilities\n");
596 }
597
598 #else
599 static inline void cpu_register_vulnerabilities(void) { }
600 #endif
601
602 void __init cpu_dev_init(void)
603 {
604         if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
605                 panic("Failed to register CPU subsystem");
606
607         cpu_dev_register_generic();
608         cpu_register_vulnerabilities();
609 }