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1/*
2 * drivers/base/cpu.c - basic CPU class support
3 */
4
5#include <linux/sysdev.h>
6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/sched.h>
9#include <linux/cpu.h>
10#include <linux/topology.h>
11#include <linux/device.h>
12#include <linux/node.h>
13#include <linux/gfp.h>
14
15#include "base.h"
16
17static struct sysdev_class_attribute *cpu_sysdev_class_attrs[];
18
19struct sysdev_class cpu_sysdev_class = {
20 .name = "cpu",
21 .attrs = cpu_sysdev_class_attrs,
22};
23EXPORT_SYMBOL(cpu_sysdev_class);
24
25static DEFINE_PER_CPU(struct sys_device *, cpu_sys_devices);
26
27#ifdef CONFIG_HOTPLUG_CPU
28static ssize_t show_online(struct sys_device *dev, struct sysdev_attribute *attr,
29 char *buf)
30{
31 struct cpu *cpu = container_of(dev, struct cpu, sysdev);
32
33 return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id));
34}
35
36static ssize_t __ref store_online(struct sys_device *dev, struct sysdev_attribute *attr,
37 const char *buf, size_t count)
38{
39 struct cpu *cpu = container_of(dev, struct cpu, sysdev);
40 ssize_t ret;
41
42 cpu_hotplug_driver_lock();
43 switch (buf[0]) {
44 case '0':
45 ret = cpu_down(cpu->sysdev.id);
46 if (!ret)
47 kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
48 break;
49 case '1':
50 ret = cpu_up(cpu->sysdev.id);
51 if (!ret)
52 kobject_uevent(&dev->kobj, KOBJ_ONLINE);
53 break;
54 default:
55 ret = -EINVAL;
56 }
57 cpu_hotplug_driver_unlock();
58
59 if (ret >= 0)
60 ret = count;
61 return ret;
62}
63static SYSDEV_ATTR(online, 0644, show_online, store_online);
64
65static void __cpuinit register_cpu_control(struct cpu *cpu)
66{
67 sysdev_create_file(&cpu->sysdev, &attr_online);
68}
69void unregister_cpu(struct cpu *cpu)
70{
71 int logical_cpu = cpu->sysdev.id;
72
73 unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
74
75 sysdev_remove_file(&cpu->sysdev, &attr_online);
76
77 sysdev_unregister(&cpu->sysdev);
78 per_cpu(cpu_sys_devices, logical_cpu) = NULL;
79 return;
80}
81
82#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
83static ssize_t cpu_probe_store(struct sysdev_class *class,
84 struct sysdev_class_attribute *attr,
85 const char *buf,
86 size_t count)
87{
88 return arch_cpu_probe(buf, count);
89}
90
91static ssize_t cpu_release_store(struct sysdev_class *class,
92 struct sysdev_class_attribute *attr,
93 const char *buf,
94 size_t count)
95{
96 return arch_cpu_release(buf, count);
97}
98
99static SYSDEV_CLASS_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
100static SYSDEV_CLASS_ATTR(release, S_IWUSR, NULL, cpu_release_store);
101#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
102
103#else /* ... !CONFIG_HOTPLUG_CPU */
104static inline void register_cpu_control(struct cpu *cpu)
105{
106}
107#endif /* CONFIG_HOTPLUG_CPU */
108
109#ifdef CONFIG_KEXEC
110#include <linux/kexec.h>
111
112static ssize_t show_crash_notes(struct sys_device *dev, struct sysdev_attribute *attr,
113 char *buf)
114{
115 struct cpu *cpu = container_of(dev, struct cpu, sysdev);
116 ssize_t rc;
117 unsigned long long addr;
118 int cpunum;
119
120 cpunum = cpu->sysdev.id;
121
122 /*
123 * Might be reading other cpu's data based on which cpu read thread
124 * has been scheduled. But cpu data (memory) is allocated once during
125 * boot up and this data does not change there after. Hence this
126 * operation should be safe. No locking required.
127 */
128 addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
129 rc = sprintf(buf, "%Lx\n", addr);
130 return rc;
131}
132static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL);
133#endif
134
135/*
136 * Print cpu online, possible, present, and system maps
137 */
138
139struct cpu_attr {
140 struct sysdev_class_attribute attr;
141 const struct cpumask *const * const map;
142};
143
144static ssize_t show_cpus_attr(struct sysdev_class *class,
145 struct sysdev_class_attribute *attr,
146 char *buf)
147{
148 struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
149 int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
150
151 buf[n++] = '\n';
152 buf[n] = '\0';
153 return n;
154}
155
156#define _CPU_ATTR(name, map) \
157 { _SYSDEV_CLASS_ATTR(name, 0444, show_cpus_attr, NULL), map }
158
159/* Keep in sync with cpu_sysdev_class_attrs */
160static struct cpu_attr cpu_attrs[] = {
161 _CPU_ATTR(online, &cpu_online_mask),
162 _CPU_ATTR(possible, &cpu_possible_mask),
163 _CPU_ATTR(present, &cpu_present_mask),
164};
165
166/*
167 * Print values for NR_CPUS and offlined cpus
168 */
169static ssize_t print_cpus_kernel_max(struct sysdev_class *class,
170 struct sysdev_class_attribute *attr, char *buf)
171{
172 int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
173 return n;
174}
175static SYSDEV_CLASS_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
176
177/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
178unsigned int total_cpus;
179
180static ssize_t print_cpus_offline(struct sysdev_class *class,
181 struct sysdev_class_attribute *attr, char *buf)
182{
183 int n = 0, len = PAGE_SIZE-2;
184 cpumask_var_t offline;
185
186 /* display offline cpus < nr_cpu_ids */
187 if (!alloc_cpumask_var(&offline, GFP_KERNEL))
188 return -ENOMEM;
189 cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
190 n = cpulist_scnprintf(buf, len, offline);
191 free_cpumask_var(offline);
192
193 /* display offline cpus >= nr_cpu_ids */
194 if (total_cpus && nr_cpu_ids < total_cpus) {
195 if (n && n < len)
196 buf[n++] = ',';
197
198 if (nr_cpu_ids == total_cpus-1)
199 n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
200 else
201 n += snprintf(&buf[n], len - n, "%d-%d",
202 nr_cpu_ids, total_cpus-1);
203 }
204
205 n += snprintf(&buf[n], len - n, "\n");
206 return n;
207}
208static SYSDEV_CLASS_ATTR(offline, 0444, print_cpus_offline, NULL);
209
210/*
211 * register_cpu - Setup a sysfs device for a CPU.
212 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
213 * sysfs for this CPU.
214 * @num - CPU number to use when creating the device.
215 *
216 * Initialize and register the CPU device.
217 */
218int __cpuinit register_cpu(struct cpu *cpu, int num)
219{
220 int error;
221 cpu->node_id = cpu_to_node(num);
222 cpu->sysdev.id = num;
223 cpu->sysdev.cls = &cpu_sysdev_class;
224
225 error = sysdev_register(&cpu->sysdev);
226
227 if (!error && cpu->hotpluggable)
228 register_cpu_control(cpu);
229 if (!error)
230 per_cpu(cpu_sys_devices, num) = &cpu->sysdev;
231 if (!error)
232 register_cpu_under_node(num, cpu_to_node(num));
233
234#ifdef CONFIG_KEXEC
235 if (!error)
236 error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes);
237#endif
238 return error;
239}
240
241struct sys_device *get_cpu_sysdev(unsigned cpu)
242{
243 if (cpu < nr_cpu_ids && cpu_possible(cpu))
244 return per_cpu(cpu_sys_devices, cpu);
245 else
246 return NULL;
247}
248EXPORT_SYMBOL_GPL(get_cpu_sysdev);
249
250int __init cpu_dev_init(void)
251{
252 int err;
253
254 err = sysdev_class_register(&cpu_sysdev_class);
255#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
256 if (!err)
257 err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);
258#endif
259
260 return err;
261}
262
263static struct sysdev_class_attribute *cpu_sysdev_class_attrs[] = {
264#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
265 &attr_probe,
266 &attr_release,
267#endif
268 &cpu_attrs[0].attr,
269 &cpu_attrs[1].attr,
270 &cpu_attrs[2].attr,
271 &attr_kernel_max,
272 &attr_offline,
273 NULL
274};
1/*
2 * CPU subsystem support
3 */
4
5#include <linux/kernel.h>
6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/sched.h>
9#include <linux/cpu.h>
10#include <linux/topology.h>
11#include <linux/device.h>
12#include <linux/node.h>
13#include <linux/gfp.h>
14#include <linux/slab.h>
15#include <linux/percpu.h>
16#include <linux/acpi.h>
17#include <linux/of.h>
18#include <linux/cpufeature.h>
19
20#include "base.h"
21
22static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
23
24static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
25{
26 /* ACPI style match is the only one that may succeed. */
27 if (acpi_driver_match_device(dev, drv))
28 return 1;
29
30 return 0;
31}
32
33#ifdef CONFIG_HOTPLUG_CPU
34static void change_cpu_under_node(struct cpu *cpu,
35 unsigned int from_nid, unsigned int to_nid)
36{
37 int cpuid = cpu->dev.id;
38 unregister_cpu_under_node(cpuid, from_nid);
39 register_cpu_under_node(cpuid, to_nid);
40 cpu->node_id = to_nid;
41}
42
43static int __ref cpu_subsys_online(struct device *dev)
44{
45 struct cpu *cpu = container_of(dev, struct cpu, dev);
46 int cpuid = dev->id;
47 int from_nid, to_nid;
48 int ret;
49
50 from_nid = cpu_to_node(cpuid);
51 if (from_nid == NUMA_NO_NODE)
52 return -ENODEV;
53
54 ret = cpu_up(cpuid);
55 /*
56 * When hot adding memory to memoryless node and enabling a cpu
57 * on the node, node number of the cpu may internally change.
58 */
59 to_nid = cpu_to_node(cpuid);
60 if (from_nid != to_nid)
61 change_cpu_under_node(cpu, from_nid, to_nid);
62
63 return ret;
64}
65
66static int cpu_subsys_offline(struct device *dev)
67{
68 return cpu_down(dev->id);
69}
70
71void unregister_cpu(struct cpu *cpu)
72{
73 int logical_cpu = cpu->dev.id;
74
75 unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
76
77 device_unregister(&cpu->dev);
78 per_cpu(cpu_sys_devices, logical_cpu) = NULL;
79 return;
80}
81
82#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
83static ssize_t cpu_probe_store(struct device *dev,
84 struct device_attribute *attr,
85 const char *buf,
86 size_t count)
87{
88 ssize_t cnt;
89 int ret;
90
91 ret = lock_device_hotplug_sysfs();
92 if (ret)
93 return ret;
94
95 cnt = arch_cpu_probe(buf, count);
96
97 unlock_device_hotplug();
98 return cnt;
99}
100
101static ssize_t cpu_release_store(struct device *dev,
102 struct device_attribute *attr,
103 const char *buf,
104 size_t count)
105{
106 ssize_t cnt;
107 int ret;
108
109 ret = lock_device_hotplug_sysfs();
110 if (ret)
111 return ret;
112
113 cnt = arch_cpu_release(buf, count);
114
115 unlock_device_hotplug();
116 return cnt;
117}
118
119static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
120static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
121#endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
122#endif /* CONFIG_HOTPLUG_CPU */
123
124struct bus_type cpu_subsys = {
125 .name = "cpu",
126 .dev_name = "cpu",
127 .match = cpu_subsys_match,
128#ifdef CONFIG_HOTPLUG_CPU
129 .online = cpu_subsys_online,
130 .offline = cpu_subsys_offline,
131#endif
132};
133EXPORT_SYMBOL_GPL(cpu_subsys);
134
135#ifdef CONFIG_KEXEC
136#include <linux/kexec.h>
137
138static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr,
139 char *buf)
140{
141 struct cpu *cpu = container_of(dev, struct cpu, dev);
142 ssize_t rc;
143 unsigned long long addr;
144 int cpunum;
145
146 cpunum = cpu->dev.id;
147
148 /*
149 * Might be reading other cpu's data based on which cpu read thread
150 * has been scheduled. But cpu data (memory) is allocated once during
151 * boot up and this data does not change there after. Hence this
152 * operation should be safe. No locking required.
153 */
154 addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
155 rc = sprintf(buf, "%Lx\n", addr);
156 return rc;
157}
158static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
159
160static ssize_t show_crash_notes_size(struct device *dev,
161 struct device_attribute *attr,
162 char *buf)
163{
164 ssize_t rc;
165
166 rc = sprintf(buf, "%zu\n", sizeof(note_buf_t));
167 return rc;
168}
169static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL);
170
171static struct attribute *crash_note_cpu_attrs[] = {
172 &dev_attr_crash_notes.attr,
173 &dev_attr_crash_notes_size.attr,
174 NULL
175};
176
177static struct attribute_group crash_note_cpu_attr_group = {
178 .attrs = crash_note_cpu_attrs,
179};
180#endif
181
182static const struct attribute_group *common_cpu_attr_groups[] = {
183#ifdef CONFIG_KEXEC
184 &crash_note_cpu_attr_group,
185#endif
186 NULL
187};
188
189static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
190#ifdef CONFIG_KEXEC
191 &crash_note_cpu_attr_group,
192#endif
193 NULL
194};
195
196/*
197 * Print cpu online, possible, present, and system maps
198 */
199
200struct cpu_attr {
201 struct device_attribute attr;
202 const struct cpumask *const * const map;
203};
204
205static ssize_t show_cpus_attr(struct device *dev,
206 struct device_attribute *attr,
207 char *buf)
208{
209 struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
210 int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
211
212 buf[n++] = '\n';
213 buf[n] = '\0';
214 return n;
215}
216
217#define _CPU_ATTR(name, map) \
218 { __ATTR(name, 0444, show_cpus_attr, NULL), map }
219
220/* Keep in sync with cpu_subsys_attrs */
221static struct cpu_attr cpu_attrs[] = {
222 _CPU_ATTR(online, &cpu_online_mask),
223 _CPU_ATTR(possible, &cpu_possible_mask),
224 _CPU_ATTR(present, &cpu_present_mask),
225};
226
227/*
228 * Print values for NR_CPUS and offlined cpus
229 */
230static ssize_t print_cpus_kernel_max(struct device *dev,
231 struct device_attribute *attr, char *buf)
232{
233 int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
234 return n;
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 = cpulist_scnprintf(buf, len, 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 += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
261 else
262 n += snprintf(&buf[n], len - n, "%d-%d",
263 nr_cpu_ids, total_cpus-1);
264 }
265
266 n += snprintf(&buf[n], len - n, "\n");
267 return n;
268}
269static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
270
271static void cpu_device_release(struct device *dev)
272{
273 /*
274 * This is an empty function to prevent the driver core from spitting a
275 * warning at us. Yes, I know this is directly opposite of what the
276 * documentation for the driver core and kobjects say, and the author
277 * of this code has already been publically ridiculed for doing
278 * something as foolish as this. However, at this point in time, it is
279 * the only way to handle the issue of statically allocated cpu
280 * devices. The different architectures will have their cpu device
281 * code reworked to properly handle this in the near future, so this
282 * function will then be changed to correctly free up the memory held
283 * by the cpu device.
284 *
285 * Never copy this way of doing things, or you too will be made fun of
286 * on the linux-kernel list, you have been warned.
287 */
288}
289
290#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
291static ssize_t print_cpu_modalias(struct device *dev,
292 struct device_attribute *attr,
293 char *buf)
294{
295 ssize_t n;
296 u32 i;
297
298 n = sprintf(buf, "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
299 CPU_FEATURE_TYPEVAL);
300
301 for (i = 0; i < MAX_CPU_FEATURES; i++)
302 if (cpu_have_feature(i)) {
303 if (PAGE_SIZE < n + sizeof(",XXXX\n")) {
304 WARN(1, "CPU features overflow page\n");
305 break;
306 }
307 n += sprintf(&buf[n], ",%04X", i);
308 }
309 buf[n++] = '\n';
310 return n;
311}
312
313static int cpu_uevent(struct device *dev, struct kobj_uevent_env *env)
314{
315 char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
316 if (buf) {
317 print_cpu_modalias(NULL, NULL, buf);
318 add_uevent_var(env, "MODALIAS=%s", buf);
319 kfree(buf);
320 }
321 return 0;
322}
323#endif
324
325/*
326 * register_cpu - Setup a sysfs device for a CPU.
327 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
328 * sysfs for this CPU.
329 * @num - CPU number to use when creating the device.
330 *
331 * Initialize and register the CPU device.
332 */
333int register_cpu(struct cpu *cpu, int num)
334{
335 int error;
336
337 cpu->node_id = cpu_to_node(num);
338 memset(&cpu->dev, 0x00, sizeof(struct device));
339 cpu->dev.id = num;
340 cpu->dev.bus = &cpu_subsys;
341 cpu->dev.release = cpu_device_release;
342 cpu->dev.offline_disabled = !cpu->hotpluggable;
343 cpu->dev.offline = !cpu_online(num);
344 cpu->dev.of_node = of_get_cpu_node(num, NULL);
345#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
346 cpu->dev.bus->uevent = cpu_uevent;
347#endif
348 cpu->dev.groups = common_cpu_attr_groups;
349 if (cpu->hotpluggable)
350 cpu->dev.groups = hotplugable_cpu_attr_groups;
351 error = device_register(&cpu->dev);
352 if (!error)
353 per_cpu(cpu_sys_devices, num) = &cpu->dev;
354 if (!error)
355 register_cpu_under_node(num, cpu_to_node(num));
356
357 return error;
358}
359
360struct device *get_cpu_device(unsigned cpu)
361{
362 if (cpu < nr_cpu_ids && cpu_possible(cpu))
363 return per_cpu(cpu_sys_devices, cpu);
364 else
365 return NULL;
366}
367EXPORT_SYMBOL_GPL(get_cpu_device);
368
369#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
370static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
371#endif
372
373static struct attribute *cpu_root_attrs[] = {
374#ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
375 &dev_attr_probe.attr,
376 &dev_attr_release.attr,
377#endif
378 &cpu_attrs[0].attr.attr,
379 &cpu_attrs[1].attr.attr,
380 &cpu_attrs[2].attr.attr,
381 &dev_attr_kernel_max.attr,
382 &dev_attr_offline.attr,
383#ifdef CONFIG_GENERIC_CPU_AUTOPROBE
384 &dev_attr_modalias.attr,
385#endif
386 NULL
387};
388
389static struct attribute_group cpu_root_attr_group = {
390 .attrs = cpu_root_attrs,
391};
392
393static const struct attribute_group *cpu_root_attr_groups[] = {
394 &cpu_root_attr_group,
395 NULL,
396};
397
398bool cpu_is_hotpluggable(unsigned cpu)
399{
400 struct device *dev = get_cpu_device(cpu);
401 return dev && container_of(dev, struct cpu, dev)->hotpluggable;
402}
403EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
404
405#ifdef CONFIG_GENERIC_CPU_DEVICES
406static DEFINE_PER_CPU(struct cpu, cpu_devices);
407#endif
408
409static void __init cpu_dev_register_generic(void)
410{
411#ifdef CONFIG_GENERIC_CPU_DEVICES
412 int i;
413
414 for_each_possible_cpu(i) {
415 if (register_cpu(&per_cpu(cpu_devices, i), i))
416 panic("Failed to register CPU device");
417 }
418#endif
419}
420
421void __init cpu_dev_init(void)
422{
423 if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
424 panic("Failed to register CPU subsystem");
425
426 cpu_dev_register_generic();
427}