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 
cpu_subsys_match(struct device * dev,struct device_driver * drv)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
change_cpu_under_node(struct cpu * cpu,unsigned int from_nid,unsigned int to_nid)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 
cpu_subsys_online(struct device * dev)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 
cpu_subsys_offline(struct device * dev)70 static int cpu_subsys_offline(struct device *dev)
71 {
72 	return cpu_down(dev->id);
73 }
74 
unregister_cpu(struct cpu * cpu)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
cpu_probe_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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 
cpu_release_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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 
show_crash_notes(struct device * dev,struct device_attribute * attr,char * buf)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 
show_crash_notes_size(struct device * dev,struct device_attribute * attr,char * buf)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 
show_cpus_attr(struct device * dev,struct device_attribute * attr,char * buf)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  */
print_cpus_kernel_max(struct device * dev,struct device_attribute * attr,char * buf)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 
print_cpus_offline(struct device * dev,struct device_attribute * attr,char * buf)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 
print_cpus_isolated(struct device * dev,struct device_attribute * attr,char * buf)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
print_cpus_nohz_full(struct device * dev,struct device_attribute * attr,char * buf)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 
cpu_device_release(struct device * dev)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
print_cpu_modalias(struct device * dev,struct device_attribute * attr,char * buf)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 
cpu_uevent(struct device * dev,struct kobj_uevent_env * env)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  */
register_cpu(struct cpu * cpu,int num)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 
get_cpu_device(unsigned cpu)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 
device_create_release(struct device * dev)407 static void device_create_release(struct device *dev)
408 {
409 	kfree(dev);
410 }
411 
412 static struct device *
__cpu_device_create(struct device * parent,void * drvdata,const struct attribute_group ** groups,const char * fmt,va_list args)413 __cpu_device_create(struct device *parent, void *drvdata,
414 		    const struct attribute_group **groups,
415 		    const char *fmt, va_list args)
416 {
417 	struct device *dev = NULL;
418 	int retval = -ENODEV;
419 
420 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
421 	if (!dev) {
422 		retval = -ENOMEM;
423 		goto error;
424 	}
425 
426 	device_initialize(dev);
427 	dev->parent = parent;
428 	dev->groups = groups;
429 	dev->release = device_create_release;
430 	dev_set_drvdata(dev, drvdata);
431 
432 	retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
433 	if (retval)
434 		goto error;
435 
436 	retval = device_add(dev);
437 	if (retval)
438 		goto error;
439 
440 	return dev;
441 
442 error:
443 	put_device(dev);
444 	return ERR_PTR(retval);
445 }
446 
cpu_device_create(struct device * parent,void * drvdata,const struct attribute_group ** groups,const char * fmt,...)447 struct device *cpu_device_create(struct device *parent, void *drvdata,
448 				 const struct attribute_group **groups,
449 				 const char *fmt, ...)
450 {
451 	va_list vargs;
452 	struct device *dev;
453 
454 	va_start(vargs, fmt);
455 	dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
456 	va_end(vargs);
457 	return dev;
458 }
459 EXPORT_SYMBOL_GPL(cpu_device_create);
460 
461 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
462 static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
463 #endif
464 
465 static struct attribute *cpu_root_attrs[] = {
466 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
467 	&dev_attr_probe.attr,
468 	&dev_attr_release.attr,
469 #endif
470 	&cpu_attrs[0].attr.attr,
471 	&cpu_attrs[1].attr.attr,
472 	&cpu_attrs[2].attr.attr,
473 	&dev_attr_kernel_max.attr,
474 	&dev_attr_offline.attr,
475 	&dev_attr_isolated.attr,
476 #ifdef CONFIG_NO_HZ_FULL
477 	&dev_attr_nohz_full.attr,
478 #endif
479 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
480 	&dev_attr_modalias.attr,
481 #endif
482 	NULL
483 };
484 
485 static struct attribute_group cpu_root_attr_group = {
486 	.attrs = cpu_root_attrs,
487 };
488 
489 static const struct attribute_group *cpu_root_attr_groups[] = {
490 	&cpu_root_attr_group,
491 	NULL,
492 };
493 
cpu_is_hotpluggable(unsigned cpu)494 bool cpu_is_hotpluggable(unsigned cpu)
495 {
496 	struct device *dev = get_cpu_device(cpu);
497 	return dev && container_of(dev, struct cpu, dev)->hotpluggable
498 		&& tick_nohz_cpu_hotpluggable(cpu);
499 }
500 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
501 
502 #ifdef CONFIG_GENERIC_CPU_DEVICES
503 static DEFINE_PER_CPU(struct cpu, cpu_devices);
504 #endif
505 
cpu_dev_register_generic(void)506 static void __init cpu_dev_register_generic(void)
507 {
508 #ifdef CONFIG_GENERIC_CPU_DEVICES
509 	int i;
510 
511 	for_each_possible_cpu(i) {
512 		if (register_cpu(&per_cpu(cpu_devices, i), i))
513 			panic("Failed to register CPU device");
514 	}
515 #endif
516 }
517 
518 #ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
519 
cpu_show_meltdown(struct device * dev,struct device_attribute * attr,char * buf)520 ssize_t __weak cpu_show_meltdown(struct device *dev,
521 				 struct device_attribute *attr, char *buf)
522 {
523 	return sprintf(buf, "Not affected\n");
524 }
525 
cpu_show_spectre_v1(struct device * dev,struct device_attribute * attr,char * buf)526 ssize_t __weak cpu_show_spectre_v1(struct device *dev,
527 				   struct device_attribute *attr, char *buf)
528 {
529 	return sprintf(buf, "Not affected\n");
530 }
531 
cpu_show_spectre_v2(struct device * dev,struct device_attribute * attr,char * buf)532 ssize_t __weak cpu_show_spectre_v2(struct device *dev,
533 				   struct device_attribute *attr, char *buf)
534 {
535 	return sprintf(buf, "Not affected\n");
536 }
537 
cpu_show_spec_store_bypass(struct device * dev,struct device_attribute * attr,char * buf)538 ssize_t __weak cpu_show_spec_store_bypass(struct device *dev,
539 					  struct device_attribute *attr, char *buf)
540 {
541 	return sprintf(buf, "Not affected\n");
542 }
543 
cpu_show_l1tf(struct device * dev,struct device_attribute * attr,char * buf)544 ssize_t __weak cpu_show_l1tf(struct device *dev,
545 			     struct device_attribute *attr, char *buf)
546 {
547 	return sprintf(buf, "Not affected\n");
548 }
549 
cpu_show_mds(struct device * dev,struct device_attribute * attr,char * buf)550 ssize_t __weak cpu_show_mds(struct device *dev,
551 			    struct device_attribute *attr, char *buf)
552 {
553 	return sprintf(buf, "Not affected\n");
554 }
555 
cpu_show_tsx_async_abort(struct device * dev,struct device_attribute * attr,char * buf)556 ssize_t __weak cpu_show_tsx_async_abort(struct device *dev,
557 					struct device_attribute *attr,
558 					char *buf)
559 {
560 	return sprintf(buf, "Not affected\n");
561 }
562 
cpu_show_itlb_multihit(struct device * dev,struct device_attribute * attr,char * buf)563 ssize_t __weak cpu_show_itlb_multihit(struct device *dev,
564 			    struct device_attribute *attr, char *buf)
565 {
566 	return sprintf(buf, "Not affected\n");
567 }
568 
cpu_show_srbds(struct device * dev,struct device_attribute * attr,char * buf)569 ssize_t __weak cpu_show_srbds(struct device *dev,
570 			      struct device_attribute *attr, char *buf)
571 {
572 	return sprintf(buf, "Not affected\n");
573 }
574 
cpu_show_mmio_stale_data(struct device * dev,struct device_attribute * attr,char * buf)575 ssize_t __weak cpu_show_mmio_stale_data(struct device *dev,
576 					struct device_attribute *attr, char *buf)
577 {
578 	return sysfs_emit(buf, "Not affected\n");
579 }
580 
cpu_show_retbleed(struct device * dev,struct device_attribute * attr,char * buf)581 ssize_t __weak cpu_show_retbleed(struct device *dev,
582 				 struct device_attribute *attr, char *buf)
583 {
584 	return sysfs_emit(buf, "Not affected\n");
585 }
586 
cpu_show_gds(struct device * dev,struct device_attribute * attr,char * buf)587 ssize_t __weak cpu_show_gds(struct device *dev,
588 			    struct device_attribute *attr, char *buf)
589 {
590 	return sysfs_emit(buf, "Not affected\n");
591 }
592 
593 static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
594 static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
595 static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
596 static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
597 static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
598 static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
599 static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
600 static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
601 static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
602 static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
603 static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
604 static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
605 
606 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
607 	&dev_attr_meltdown.attr,
608 	&dev_attr_spectre_v1.attr,
609 	&dev_attr_spectre_v2.attr,
610 	&dev_attr_spec_store_bypass.attr,
611 	&dev_attr_l1tf.attr,
612 	&dev_attr_mds.attr,
613 	&dev_attr_tsx_async_abort.attr,
614 	&dev_attr_itlb_multihit.attr,
615 	&dev_attr_srbds.attr,
616 	&dev_attr_mmio_stale_data.attr,
617 	&dev_attr_retbleed.attr,
618 	&dev_attr_gather_data_sampling.attr,
619 	NULL
620 };
621 
622 static const struct attribute_group cpu_root_vulnerabilities_group = {
623 	.name  = "vulnerabilities",
624 	.attrs = cpu_root_vulnerabilities_attrs,
625 };
626 
cpu_register_vulnerabilities(void)627 static void __init cpu_register_vulnerabilities(void)
628 {
629 	if (sysfs_create_group(&cpu_subsys.dev_root->kobj,
630 			       &cpu_root_vulnerabilities_group))
631 		pr_err("Unable to register CPU vulnerabilities\n");
632 }
633 
634 #else
cpu_register_vulnerabilities(void)635 static inline void cpu_register_vulnerabilities(void) { }
636 #endif
637 
cpu_dev_init(void)638 void __init cpu_dev_init(void)
639 {
640 	if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
641 		panic("Failed to register CPU subsystem");
642 
643 	cpu_dev_register_generic();
644 	cpu_register_vulnerabilities();
645 }
646