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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
26static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
27
28static 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
38static 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
47static 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
70static int cpu_subsys_offline(struct device *dev)
71{
72 return cpu_device_down(dev);
73}
74
75void 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
87static 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
105static 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
123static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
124static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
125#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
126#endif /* CONFIG_HOTPLUG_CPU */
127
128struct 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};
137EXPORT_SYMBOL_GPL(cpu_subsys);
138
139#ifdef CONFIG_KEXEC
140#include <linux/kexec.h>
141
142static 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}
162static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
163
164static 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}
173static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
174
175static struct attribute *crash_note_cpu_attrs[] = {
176 &dev_attr_crash_notes.attr,
177 &dev_attr_crash_notes_size.attr,
178 NULL
179};
180
181static struct attribute_group crash_note_cpu_attr_group = {
182 .attrs = crash_note_cpu_attrs,
183};
184#endif
185
186static const struct attribute_group *common_cpu_attr_groups[] = {
187#ifdef CONFIG_KEXEC
188 &crash_note_cpu_attr_group,
189#endif
190 NULL
191};
192
193static 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
204struct cpu_attr {
205 struct device_attribute attr;
206 const struct cpumask *const map;
207};
208
209static 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 */
222static 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 */
231static 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}
236static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
237
238/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
239unsigned int total_cpus;
240
241static 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}
269static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
270
271static 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}
288static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
289
290#ifdef CONFIG_NO_HZ_FULL
291static 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}
296static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
297#endif
298
299static 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
319static 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
341static 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 */
361int 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
393struct 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}
400EXPORT_SYMBOL_GPL(get_cpu_device);
401
402static void device_create_release(struct device *dev)
403{
404 kfree(dev);
405}
406
407__printf(4, 0)
408static 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
439error:
440 put_device(dev);
441 return ERR_PTR(retval);
442}
443
444struct 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}
456EXPORT_SYMBOL_GPL(cpu_device_create);
457
458#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
459static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
460#endif
461
462static 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
482static struct attribute_group cpu_root_attr_group = {
483 .attrs = cpu_root_attrs,
484};
485
486static const struct attribute_group *cpu_root_attr_groups[] = {
487 &cpu_root_attr_group,
488 NULL,
489};
490
491bool 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}
496EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
497
498#ifdef CONFIG_GENERIC_CPU_DEVICES
499static DEFINE_PER_CPU(struct cpu, cpu_devices);
500#endif
501
502static 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
516ssize_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
522ssize_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
528ssize_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
534ssize_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
540ssize_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
546ssize_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
552ssize_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
559ssize_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
565ssize_t __weak cpu_show_srbds(struct device *dev,
566 struct device_attribute *attr, char *buf)
567{
568 return sprintf(buf, "Not affected\n");
569}
570
571static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
572static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
573static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
574static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
575static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
576static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
577static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
578static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
579static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
580
581static struct attribute *cpu_root_vulnerabilities_attrs[] = {
582 &dev_attr_meltdown.attr,
583 &dev_attr_spectre_v1.attr,
584 &dev_attr_spectre_v2.attr,
585 &dev_attr_spec_store_bypass.attr,
586 &dev_attr_l1tf.attr,
587 &dev_attr_mds.attr,
588 &dev_attr_tsx_async_abort.attr,
589 &dev_attr_itlb_multihit.attr,
590 &dev_attr_srbds.attr,
591 NULL
592};
593
594static const struct attribute_group cpu_root_vulnerabilities_group = {
595 .name = "vulnerabilities",
596 .attrs = cpu_root_vulnerabilities_attrs,
597};
598
599static void __init cpu_register_vulnerabilities(void)
600{
601 if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
602 &cpu_root_vulnerabilities_group))
603 pr_err("Unable to register CPU vulnerabilities\n");
604}
605
606#else
607static inline void cpu_register_vulnerabilities(void) { }
608#endif
609
610void __init cpu_dev_init(void)
611{
612 if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
613 panic("Failed to register CPU subsystem");
614
615 cpu_dev_register_generic();
616 cpu_register_vulnerabilities();
617}
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
26static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
27
28static 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
38static 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
47static 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
70static int cpu_subsys_offline(struct device *dev)
71{
72 return cpu_device_down(dev);
73}
74
75void 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
87static 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
105static 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
123static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
124static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
125#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
126#endif /* CONFIG_HOTPLUG_CPU */
127
128struct 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};
137EXPORT_SYMBOL_GPL(cpu_subsys);
138
139#ifdef CONFIG_KEXEC
140#include <linux/kexec.h>
141
142static ssize_t crash_notes_show(struct device *dev,
143 struct device_attribute *attr,
144 char *buf)
145{
146 struct cpu *cpu = container_of(dev, struct cpu, dev);
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
160 return sysfs_emit(buf, "%llx\n", addr);
161}
162static DEVICE_ATTR_ADMIN_RO(crash_notes);
163
164static ssize_t crash_notes_size_show(struct device *dev,
165 struct device_attribute *attr,
166 char *buf)
167{
168 return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t));
169}
170static DEVICE_ATTR_ADMIN_RO(crash_notes_size);
171
172static struct attribute *crash_note_cpu_attrs[] = {
173 &dev_attr_crash_notes.attr,
174 &dev_attr_crash_notes_size.attr,
175 NULL
176};
177
178static const struct attribute_group crash_note_cpu_attr_group = {
179 .attrs = crash_note_cpu_attrs,
180};
181#endif
182
183static const struct attribute_group *common_cpu_attr_groups[] = {
184#ifdef CONFIG_KEXEC
185 &crash_note_cpu_attr_group,
186#endif
187 NULL
188};
189
190static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
191#ifdef CONFIG_KEXEC
192 &crash_note_cpu_attr_group,
193#endif
194 NULL
195};
196
197/*
198 * Print cpu online, possible, present, and system maps
199 */
200
201struct cpu_attr {
202 struct device_attribute attr;
203 const struct cpumask *const map;
204};
205
206static ssize_t show_cpus_attr(struct device *dev,
207 struct device_attribute *attr,
208 char *buf)
209{
210 struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
211
212 return cpumap_print_to_pagebuf(true, buf, ca->map);
213}
214
215#define _CPU_ATTR(name, map) \
216 { __ATTR(name, 0444, show_cpus_attr, NULL), map }
217
218/* Keep in sync with cpu_subsys_attrs */
219static struct cpu_attr cpu_attrs[] = {
220 _CPU_ATTR(online, &__cpu_online_mask),
221 _CPU_ATTR(possible, &__cpu_possible_mask),
222 _CPU_ATTR(present, &__cpu_present_mask),
223};
224
225/*
226 * Print values for NR_CPUS and offlined cpus
227 */
228static ssize_t print_cpus_kernel_max(struct device *dev,
229 struct device_attribute *attr, char *buf)
230{
231 return sysfs_emit(buf, "%d\n", NR_CPUS - 1);
232}
233static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
234
235/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
236unsigned int total_cpus;
237
238static ssize_t print_cpus_offline(struct device *dev,
239 struct device_attribute *attr, char *buf)
240{
241 int len = 0;
242 cpumask_var_t offline;
243
244 /* display offline cpus < nr_cpu_ids */
245 if (!alloc_cpumask_var(&offline, GFP_KERNEL))
246 return -ENOMEM;
247 cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
248 len += sysfs_emit_at(buf, len, "%*pbl", cpumask_pr_args(offline));
249 free_cpumask_var(offline);
250
251 /* display offline cpus >= nr_cpu_ids */
252 if (total_cpus && nr_cpu_ids < total_cpus) {
253 len += sysfs_emit_at(buf, len, ",");
254
255 if (nr_cpu_ids == total_cpus-1)
256 len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids);
257 else
258 len += sysfs_emit_at(buf, len, "%u-%d",
259 nr_cpu_ids, total_cpus - 1);
260 }
261
262 len += sysfs_emit_at(buf, len, "\n");
263
264 return len;
265}
266static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
267
268static ssize_t print_cpus_isolated(struct device *dev,
269 struct device_attribute *attr, char *buf)
270{
271 int len;
272 cpumask_var_t isolated;
273
274 if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
275 return -ENOMEM;
276
277 cpumask_andnot(isolated, cpu_possible_mask,
278 housekeeping_cpumask(HK_TYPE_DOMAIN));
279 len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated));
280
281 free_cpumask_var(isolated);
282
283 return len;
284}
285static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
286
287#ifdef CONFIG_NO_HZ_FULL
288static ssize_t print_cpus_nohz_full(struct device *dev,
289 struct device_attribute *attr, char *buf)
290{
291 return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
292}
293static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
294#endif
295
296static void cpu_device_release(struct device *dev)
297{
298 /*
299 * This is an empty function to prevent the driver core from spitting a
300 * warning at us. Yes, I know this is directly opposite of what the
301 * documentation for the driver core and kobjects say, and the author
302 * of this code has already been publically ridiculed for doing
303 * something as foolish as this. However, at this point in time, it is
304 * the only way to handle the issue of statically allocated cpu
305 * devices. The different architectures will have their cpu device
306 * code reworked to properly handle this in the near future, so this
307 * function will then be changed to correctly free up the memory held
308 * by the cpu device.
309 *
310 * Never copy this way of doing things, or you too will be made fun of
311 * on the linux-kernel list, you have been warned.
312 */
313}
314
315#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
316static ssize_t print_cpu_modalias(struct device *dev,
317 struct device_attribute *attr,
318 char *buf)
319{
320 int len = 0;
321 u32 i;
322
323 len += sysfs_emit_at(buf, len,
324 "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
325 CPU_FEATURE_TYPEVAL);
326
327 for (i = 0; i < MAX_CPU_FEATURES; i++)
328 if (cpu_have_feature(i)) {
329 if (len + sizeof(",XXXX\n") >= PAGE_SIZE) {
330 WARN(1, "CPU features overflow page\n");
331 break;
332 }
333 len += sysfs_emit_at(buf, len, ",%04X", i);
334 }
335 len += sysfs_emit_at(buf, len, "\n");
336 return len;
337}
338
339static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
340{
341 char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
342 if (buf) {
343 print_cpu_modalias(NULL, NULL, buf);
344 add_uevent_var(env, "MODALIAS=%s", buf);
345 kfree(buf);
346 }
347 return 0;
348}
349#endif
350
351/*
352 * register_cpu - Setup a sysfs device for a CPU.
353 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
354 * sysfs for this CPU.
355 * @num - CPU number to use when creating the device.
356 *
357 * Initialize and register the CPU device.
358 */
359int register_cpu(struct cpu *cpu, int num)
360{
361 int error;
362
363 cpu->node_id = cpu_to_node(num);
364 memset(&cpu->dev, 0x00, sizeof(struct device));
365 cpu->dev.id = num;
366 cpu->dev.bus = &cpu_subsys;
367 cpu->dev.release = cpu_device_release;
368 cpu->dev.offline_disabled = !cpu->hotpluggable;
369 cpu->dev.offline = !cpu_online(num);
370 cpu->dev.of_node = of_get_cpu_node(num, NULL);
371#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
372 cpu->dev.bus->uevent = cpu_uevent;
373#endif
374 cpu->dev.groups = common_cpu_attr_groups;
375 if (cpu->hotpluggable)
376 cpu->dev.groups = hotplugable_cpu_attr_groups;
377 error = device_register(&cpu->dev);
378 if (error) {
379 put_device(&cpu->dev);
380 return error;
381 }
382
383 per_cpu(cpu_sys_devices, num) = &cpu->dev;
384 register_cpu_under_node(num, cpu_to_node(num));
385 dev_pm_qos_expose_latency_limit(&cpu->dev,
386 PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
387
388 return 0;
389}
390
391struct device *get_cpu_device(unsigned int cpu)
392{
393 if (cpu < nr_cpu_ids && cpu_possible(cpu))
394 return per_cpu(cpu_sys_devices, cpu);
395 else
396 return NULL;
397}
398EXPORT_SYMBOL_GPL(get_cpu_device);
399
400static void device_create_release(struct device *dev)
401{
402 kfree(dev);
403}
404
405__printf(4, 0)
406static struct device *
407__cpu_device_create(struct device *parent, void *drvdata,
408 const struct attribute_group **groups,
409 const char *fmt, va_list args)
410{
411 struct device *dev = NULL;
412 int retval = -ENOMEM;
413
414 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
415 if (!dev)
416 goto error;
417
418 device_initialize(dev);
419 dev->parent = parent;
420 dev->groups = groups;
421 dev->release = device_create_release;
422 device_set_pm_not_required(dev);
423 dev_set_drvdata(dev, drvdata);
424
425 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
426 if (retval)
427 goto error;
428
429 retval = device_add(dev);
430 if (retval)
431 goto error;
432
433 return dev;
434
435error:
436 put_device(dev);
437 return ERR_PTR(retval);
438}
439
440struct device *cpu_device_create(struct device *parent, void *drvdata,
441 const struct attribute_group **groups,
442 const char *fmt, ...)
443{
444 va_list vargs;
445 struct device *dev;
446
447 va_start(vargs, fmt);
448 dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
449 va_end(vargs);
450 return dev;
451}
452EXPORT_SYMBOL_GPL(cpu_device_create);
453
454#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
455static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
456#endif
457
458static struct attribute *cpu_root_attrs[] = {
459#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
460 &dev_attr_probe.attr,
461 &dev_attr_release.attr,
462#endif
463 &cpu_attrs[0].attr.attr,
464 &cpu_attrs[1].attr.attr,
465 &cpu_attrs[2].attr.attr,
466 &dev_attr_kernel_max.attr,
467 &dev_attr_offline.attr,
468 &dev_attr_isolated.attr,
469#ifdef CONFIG_NO_HZ_FULL
470 &dev_attr_nohz_full.attr,
471#endif
472#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
473 &dev_attr_modalias.attr,
474#endif
475 NULL
476};
477
478static const struct attribute_group cpu_root_attr_group = {
479 .attrs = cpu_root_attrs,
480};
481
482static const struct attribute_group *cpu_root_attr_groups[] = {
483 &cpu_root_attr_group,
484 NULL,
485};
486
487bool cpu_is_hotpluggable(unsigned int cpu)
488{
489 struct device *dev = get_cpu_device(cpu);
490 return dev && container_of(dev, struct cpu, dev)->hotpluggable;
491}
492EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
493
494#ifdef CONFIG_GENERIC_CPU_DEVICES
495static DEFINE_PER_CPU(struct cpu, cpu_devices);
496#endif
497
498static void __init cpu_dev_register_generic(void)
499{
500#ifdef CONFIG_GENERIC_CPU_DEVICES
501 int i;
502
503 for_each_possible_cpu(i) {
504 if (register_cpu(&per_cpu(cpu_devices, i), i))
505 panic("Failed to register CPU device");
506 }
507#endif
508}
509
510#ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
511
512ssize_t __weak cpu_show_meltdown(struct device *dev,
513 struct device_attribute *attr, char *buf)
514{
515 return sysfs_emit(buf, "Not affected\n");
516}
517
518ssize_t __weak cpu_show_spectre_v1(struct device *dev,
519 struct device_attribute *attr, char *buf)
520{
521 return sysfs_emit(buf, "Not affected\n");
522}
523
524ssize_t __weak cpu_show_spectre_v2(struct device *dev,
525 struct device_attribute *attr, char *buf)
526{
527 return sysfs_emit(buf, "Not affected\n");
528}
529
530ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
531 struct device_attribute *attr, char *buf)
532{
533 return sysfs_emit(buf, "Not affected\n");
534}
535
536ssize_t __weak cpu_show_l1tf(struct device *dev,
537 struct device_attribute *attr, char *buf)
538{
539 return sysfs_emit(buf, "Not affected\n");
540}
541
542ssize_t __weak cpu_show_mds(struct device *dev,
543 struct device_attribute *attr, char *buf)
544{
545 return sysfs_emit(buf, "Not affected\n");
546}
547
548ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
549 struct device_attribute *attr,
550 char *buf)
551{
552 return sysfs_emit(buf, "Not affected\n");
553}
554
555ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
556 struct device_attribute *attr, char *buf)
557{
558 return sysfs_emit(buf, "Not affected\n");
559}
560
561ssize_t __weak cpu_show_srbds(struct device *dev,
562 struct device_attribute *attr, char *buf)
563{
564 return sysfs_emit(buf, "Not affected\n");
565}
566
567ssize_t __weak cpu_show_mmio_stale_data(struct device *dev,
568 struct device_attribute *attr, char *buf)
569{
570 return sysfs_emit(buf, "Not affected\n");
571}
572
573ssize_t __weak cpu_show_retbleed(struct device *dev,
574 struct device_attribute *attr, char *buf)
575{
576 return sysfs_emit(buf, "Not affected\n");
577}
578
579static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
580static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
581static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
582static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
583static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
584static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
585static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
586static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
587static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
588static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
589static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
590
591static struct attribute *cpu_root_vulnerabilities_attrs[] = {
592 &dev_attr_meltdown.attr,
593 &dev_attr_spectre_v1.attr,
594 &dev_attr_spectre_v2.attr,
595 &dev_attr_spec_store_bypass.attr,
596 &dev_attr_l1tf.attr,
597 &dev_attr_mds.attr,
598 &dev_attr_tsx_async_abort.attr,
599 &dev_attr_itlb_multihit.attr,
600 &dev_attr_srbds.attr,
601 &dev_attr_mmio_stale_data.attr,
602 &dev_attr_retbleed.attr,
603 NULL
604};
605
606static const struct attribute_group cpu_root_vulnerabilities_group = {
607 .name = "vulnerabilities",
608 .attrs = cpu_root_vulnerabilities_attrs,
609};
610
611static void __init cpu_register_vulnerabilities(void)
612{
613 if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
614 &cpu_root_vulnerabilities_group))
615 pr_err("Unable to register CPU vulnerabilities\n");
616}
617
618#else
619static inline void cpu_register_vulnerabilities(void) { }
620#endif
621
622void __init cpu_dev_init(void)
623{
624 if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
625 panic("Failed to register CPU subsystem");
626
627 cpu_dev_register_generic();
628 cpu_register_vulnerabilities();
629}