Merge branch 'pcmcia-next' of git://git.kernel.org/pub/scm/linux/kernel/git/brodo...
[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_up(cpuid);
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_down(dev->id);
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         int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
235         return n;
236 }
237 static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
238
239 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
240 unsigned int total_cpus;
241
242 static ssize_t print_cpus_offline(struct device *dev,
243                                   struct device_attribute *attr, char *buf)
244 {
245         int n = 0, len = PAGE_SIZE-2;
246         cpumask_var_t offline;
247
248         /* display offline cpus < nr_cpu_ids */
249         if (!alloc_cpumask_var(&offline, GFP_KERNEL))
250                 return -ENOMEM;
251         cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
252         n = scnprintf(buf, len, "%*pbl", cpumask_pr_args(offline));
253         free_cpumask_var(offline);
254
255         /* display offline cpus >= nr_cpu_ids */
256         if (total_cpus && nr_cpu_ids < total_cpus) {
257                 if (n && n < len)
258                         buf[n++] = ',';
259
260                 if (nr_cpu_ids == total_cpus-1)
261                         n += snprintf(&buf[n], len - n, "%u", nr_cpu_ids);
262                 else
263                         n += snprintf(&buf[n], len - n, "%u-%d",
264                                                       nr_cpu_ids, total_cpus-1);
265         }
266
267         n += snprintf(&buf[n], len - n, "\n");
268         return n;
269 }
270 static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
271
272 static ssize_t print_cpus_isolated(struct device *dev,
273                                   struct device_attribute *attr, char *buf)
274 {
275         int n = 0, len = PAGE_SIZE-2;
276         cpumask_var_t isolated;
277
278         if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
279                 return -ENOMEM;
280
281         cpumask_andnot(isolated, cpu_possible_mask,
282                        housekeeping_cpumask(HK_FLAG_DOMAIN));
283         n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(isolated));
284
285         free_cpumask_var(isolated);
286
287         return n;
288 }
289 static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
290
291 #ifdef CONFIG_NO_HZ_FULL
292 static ssize_t print_cpus_nohz_full(struct device *dev,
293                                   struct device_attribute *attr, char *buf)
294 {
295         int n = 0, len = PAGE_SIZE-2;
296
297         n = scnprintf(buf, len, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
298
299         return n;
300 }
301 static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
302 #endif
303
304 static void cpu_device_release(struct device *dev)
305 {
306         /*
307          * This is an empty function to prevent the driver core from spitting a
308          * warning at us.  Yes, I know this is directly opposite of what the
309          * documentation for the driver core and kobjects say, and the author
310          * of this code has already been publically ridiculed for doing
311          * something as foolish as this.  However, at this point in time, it is
312          * the only way to handle the issue of statically allocated cpu
313          * devices.  The different architectures will have their cpu device
314          * code reworked to properly handle this in the near future, so this
315          * function will then be changed to correctly free up the memory held
316          * by the cpu device.
317          *
318          * Never copy this way of doing things, or you too will be made fun of
319          * on the linux-kernel list, you have been warned.
320          */
321 }
322
323 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
324 static ssize_t print_cpu_modalias(struct device *dev,
325                                   struct device_attribute *attr,
326                                   char *buf)
327 {
328         ssize_t n;
329         u32 i;
330
331         n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
332                     CPU_FEATURE_TYPEVAL);
333
334         for (i = 0; i < MAX_CPU_FEATURES; i++)
335                 if (cpu_have_feature(i)) {
336                         if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
337                                 WARN(1, "CPU features overflow page\n");
338                                 break;
339                         }
340                         n += sprintf(&buf[n], ",%04X", i);
341                 }
342         buf[n++] = '\n';
343         return n;
344 }
345
346 static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
347 {
348         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
349         if (buf) {
350                 print_cpu_modalias(NULL, NULL, buf);
351                 add_uevent_var(env, "MODALIAS=%s", buf);
352                 kfree(buf);
353         }
354         return 0;
355 }
356 #endif
357
358 /*
359  * register_cpu - Setup a sysfs device for a CPU.
360  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
361  *        sysfs for this CPU.
362  * @num - CPU number to use when creating the device.
363  *
364  * Initialize and register the CPU device.
365  */
366 int register_cpu(struct cpu *cpu, int num)
367 {
368         int error;
369
370         cpu->node_id = cpu_to_node(num);
371         memset(&cpu->dev, 0x00, sizeof(struct device));
372         cpu->dev.id = num;
373         cpu->dev.bus = &cpu_subsys;
374         cpu->dev.release = cpu_device_release;
375         cpu->dev.offline_disabled = !cpu->hotpluggable;
376         cpu->dev.offline = !cpu_online(num);
377         cpu->dev.of_node = of_get_cpu_node(num, NULL);
378 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
379         cpu->dev.bus->uevent = cpu_uevent;
380 #endif
381         cpu->dev.groups = common_cpu_attr_groups;
382         if (cpu->hotpluggable)
383                 cpu->dev.groups = hotplugable_cpu_attr_groups;
384         error = device_register(&cpu->dev);
385         if (error) {
386                 put_device(&cpu->dev);
387                 return error;
388         }
389
390         per_cpu(cpu_sys_devices, num) = &cpu->dev;
391         register_cpu_under_node(num, cpu_to_node(num));
392         dev_pm_qos_expose_latency_limit(&cpu->dev,
393                                         PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
394
395         return 0;
396 }
397
398 struct device *get_cpu_device(unsigned cpu)
399 {
400         if (cpu < nr_cpu_ids && cpu_possible(cpu))
401                 return per_cpu(cpu_sys_devices, cpu);
402         else
403                 return NULL;
404 }
405 EXPORT_SYMBOL_GPL(get_cpu_device);
406
407 static void device_create_release(struct device *dev)
408 {
409         kfree(dev);
410 }
411
412 __printf(4, 0)
413 static struct device *
414 __cpu_device_create(struct device *parent, void *drvdata,
415                     const struct attribute_group **groups,
416                     const char *fmt, va_list args)
417 {
418         struct device *dev = NULL;
419         int retval = -ENODEV;
420
421         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
422         if (!dev) {
423                 retval = -ENOMEM;
424                 goto error;
425         }
426
427         device_initialize(dev);
428         dev->parent = parent;
429         dev->groups = groups;
430         dev->release = device_create_release;
431         device_set_pm_not_required(dev);
432         dev_set_drvdata(dev, drvdata);
433
434         retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
435         if (retval)
436                 goto error;
437
438         retval = device_add(dev);
439         if (retval)
440                 goto error;
441
442         return dev;
443
444 error:
445         put_device(dev);
446         return ERR_PTR(retval);
447 }
448
449 struct device *cpu_device_create(struct device *parent, void *drvdata,
450                                  const struct attribute_group **groups,
451                                  const char *fmt, ...)
452 {
453         va_list vargs;
454         struct device *dev;
455
456         va_start(vargs, fmt);
457         dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
458         va_end(vargs);
459         return dev;
460 }
461 EXPORT_SYMBOL_GPL(cpu_device_create);
462
463 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
464 static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
465 #endif
466
467 static struct attribute *cpu_root_attrs[] = {
468 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
469         &dev_attr_probe.attr,
470         &dev_attr_release.attr,
471 #endif
472         &cpu_attrs[0].attr.attr,
473         &cpu_attrs[1].attr.attr,
474         &cpu_attrs[2].attr.attr,
475         &dev_attr_kernel_max.attr,
476         &dev_attr_offline.attr,
477         &dev_attr_isolated.attr,
478 #ifdef CONFIG_NO_HZ_FULL
479         &dev_attr_nohz_full.attr,
480 #endif
481 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
482         &dev_attr_modalias.attr,
483 #endif
484         NULL
485 };
486
487 static struct attribute_group cpu_root_attr_group = {
488         .attrs = cpu_root_attrs,
489 };
490
491 static const struct attribute_group *cpu_root_attr_groups[] = {
492         &cpu_root_attr_group,
493         NULL,
494 };
495
496 bool cpu_is_hotpluggable(unsigned cpu)
497 {
498         struct device *dev = get_cpu_device(cpu);
499         return dev && container_of(dev, struct cpu, dev)->hotpluggable;
500 }
501 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
502
503 #ifdef CONFIG_GENERIC_CPU_DEVICES
504 static DEFINE_PER_CPU(struct cpu, cpu_devices);
505 #endif
506
507 static void __init cpu_dev_register_generic(void)
508 {
509 #ifdef CONFIG_GENERIC_CPU_DEVICES
510         int i;
511
512         for_each_possible_cpu(i) {
513                 if (register_cpu(&per_cpu(cpu_devices, i), i))
514                         panic("Failed to register CPU device");
515         }
516 #endif
517 }
518
519 #ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
520
521 ssize_t __weak cpu_show_meltdown(struct device *dev,
522                                  struct device_attribute *attr, char *buf)
523 {
524         return sprintf(buf, "Not affected\n");
525 }
526
527 ssize_t __weak cpu_show_spectre_v1(struct device *dev,
528                                    struct device_attribute *attr, char *buf)
529 {
530         return sprintf(buf, "Not affected\n");
531 }
532
533 ssize_t __weak cpu_show_spectre_v2(struct device *dev,
534                                    struct device_attribute *attr, char *buf)
535 {
536         return sprintf(buf, "Not affected\n");
537 }
538
539 ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
540                                           struct device_attribute *attr, char *buf)
541 {
542         return sprintf(buf, "Not affected\n");
543 }
544
545 ssize_t __weak cpu_show_l1tf(struct device *dev,
546                              struct device_attribute *attr, char *buf)
547 {
548         return sprintf(buf, "Not affected\n");
549 }
550
551 ssize_t __weak cpu_show_mds(struct device *dev,
552                             struct device_attribute *attr, char *buf)
553 {
554         return sprintf(buf, "Not affected\n");
555 }
556
557 ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
558                                         struct device_attribute *attr,
559                                         char *buf)
560 {
561         return sprintf(buf, "Not affected\n");
562 }
563
564 ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
565                             struct device_attribute *attr, char *buf)
566 {
567         return sprintf(buf, "Not affected\n");
568 }
569
570 static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
571 static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
572 static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
573 static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
574 static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
575 static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
576 static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
577 static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
578
579 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
580         &dev_attr_meltdown.attr,
581         &dev_attr_spectre_v1.attr,
582         &dev_attr_spectre_v2.attr,
583         &dev_attr_spec_store_bypass.attr,
584         &dev_attr_l1tf.attr,
585         &dev_attr_mds.attr,
586         &dev_attr_tsx_async_abort.attr,
587         &dev_attr_itlb_multihit.attr,
588         NULL
589 };
590
591 static const struct attribute_group cpu_root_vulnerabilities_group = {
592         .name  = "vulnerabilities",
593         .attrs = cpu_root_vulnerabilities_attrs,
594 };
595
596 static void __init cpu_register_vulnerabilities(void)
597 {
598         if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
599                                &cpu_root_vulnerabilities_group))
600                 pr_err("Unable to register CPU vulnerabilities\n");
601 }
602
603 #else
604 static inline void cpu_register_vulnerabilities(void) { }
605 #endif
606
607 void __init cpu_dev_init(void)
608 {
609         if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
610                 panic("Failed to register CPU subsystem");
611
612         cpu_dev_register_generic();
613         cpu_register_vulnerabilities();
614 }