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Commit | Line | Data |
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1da177e4 | 1 | /* |
8a25a2fd | 2 | * CPU subsystem support |
1da177e4 LT |
3 | */ |
4 | ||
024f7846 | 5 | #include <linux/kernel.h> |
1da177e4 LT |
6 | #include <linux/module.h> |
7 | #include <linux/init.h> | |
f6a57033 | 8 | #include <linux/sched.h> |
1da177e4 LT |
9 | #include <linux/cpu.h> |
10 | #include <linux/topology.h> | |
11 | #include <linux/device.h> | |
76b67ed9 | 12 | #include <linux/node.h> |
5a0e3ad6 | 13 | #include <linux/gfp.h> |
fad12ac8 | 14 | #include <linux/slab.h> |
9f13a1fd | 15 | #include <linux/percpu.h> |
1da177e4 | 16 | |
a1bdc7aa | 17 | #include "base.h" |
1da177e4 | 18 | |
8a25a2fd | 19 | struct bus_type cpu_subsys = { |
af5ca3f4 | 20 | .name = "cpu", |
8a25a2fd | 21 | .dev_name = "cpu", |
1da177e4 | 22 | }; |
8a25a2fd | 23 | EXPORT_SYMBOL_GPL(cpu_subsys); |
1da177e4 | 24 | |
8a25a2fd | 25 | static DEFINE_PER_CPU(struct device *, cpu_sys_devices); |
ad74557a | 26 | |
1da177e4 | 27 | #ifdef CONFIG_HOTPLUG_CPU |
34640468 YI |
28 | static void change_cpu_under_node(struct cpu *cpu, |
29 | unsigned int from_nid, unsigned int to_nid) | |
30 | { | |
31 | int cpuid = cpu->dev.id; | |
32 | unregister_cpu_under_node(cpuid, from_nid); | |
33 | register_cpu_under_node(cpuid, to_nid); | |
34 | cpu->node_id = to_nid; | |
35 | } | |
36 | ||
8a25a2fd KS |
37 | static ssize_t show_online(struct device *dev, |
38 | struct device_attribute *attr, | |
4a0b2b4d | 39 | char *buf) |
1da177e4 | 40 | { |
8a25a2fd | 41 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
1da177e4 | 42 | |
8a25a2fd | 43 | return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id)); |
1da177e4 LT |
44 | } |
45 | ||
8a25a2fd KS |
46 | static ssize_t __ref store_online(struct device *dev, |
47 | struct device_attribute *attr, | |
48 | const char *buf, size_t count) | |
1da177e4 | 49 | { |
8a25a2fd | 50 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
34640468 YI |
51 | int cpuid = cpu->dev.id; |
52 | int from_nid, to_nid; | |
1da177e4 LT |
53 | ssize_t ret; |
54 | ||
51badebd | 55 | cpu_hotplug_driver_lock(); |
1da177e4 LT |
56 | switch (buf[0]) { |
57 | case '0': | |
34640468 | 58 | ret = cpu_down(cpuid); |
1da177e4 | 59 | if (!ret) |
312c004d | 60 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); |
1da177e4 LT |
61 | break; |
62 | case '1': | |
34640468 YI |
63 | from_nid = cpu_to_node(cpuid); |
64 | ret = cpu_up(cpuid); | |
65 | ||
66 | /* | |
67 | * When hot adding memory to memoryless node and enabling a cpu | |
68 | * on the node, node number of the cpu may internally change. | |
69 | */ | |
70 | to_nid = cpu_to_node(cpuid); | |
71 | if (from_nid != to_nid) | |
72 | change_cpu_under_node(cpu, from_nid, to_nid); | |
73 | ||
fb69c390 | 74 | if (!ret) |
312c004d | 75 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); |
1da177e4 LT |
76 | break; |
77 | default: | |
78 | ret = -EINVAL; | |
79 | } | |
51badebd | 80 | cpu_hotplug_driver_unlock(); |
1da177e4 LT |
81 | |
82 | if (ret >= 0) | |
83 | ret = count; | |
84 | return ret; | |
85 | } | |
8a25a2fd | 86 | static DEVICE_ATTR(online, 0644, show_online, store_online); |
1da177e4 | 87 | |
6c847402 | 88 | static void __cpuinit register_cpu_control(struct cpu *cpu) |
1da177e4 | 89 | { |
8a25a2fd | 90 | device_create_file(&cpu->dev, &dev_attr_online); |
1da177e4 | 91 | } |
76b67ed9 | 92 | void unregister_cpu(struct cpu *cpu) |
1da177e4 | 93 | { |
8a25a2fd | 94 | int logical_cpu = cpu->dev.id; |
1da177e4 | 95 | |
76b67ed9 KH |
96 | unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); |
97 | ||
8a25a2fd | 98 | device_remove_file(&cpu->dev, &dev_attr_online); |
1da177e4 | 99 | |
8a25a2fd | 100 | device_unregister(&cpu->dev); |
e37d05da | 101 | per_cpu(cpu_sys_devices, logical_cpu) = NULL; |
1da177e4 LT |
102 | return; |
103 | } | |
12633e80 NF |
104 | |
105 | #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE | |
8a25a2fd KS |
106 | static ssize_t cpu_probe_store(struct device *dev, |
107 | struct device_attribute *attr, | |
67fc233f | 108 | const char *buf, |
12633e80 NF |
109 | size_t count) |
110 | { | |
111 | return arch_cpu_probe(buf, count); | |
112 | } | |
113 | ||
8a25a2fd KS |
114 | static ssize_t cpu_release_store(struct device *dev, |
115 | struct device_attribute *attr, | |
67fc233f | 116 | const char *buf, |
12633e80 NF |
117 | size_t count) |
118 | { | |
119 | return arch_cpu_release(buf, count); | |
120 | } | |
121 | ||
8a25a2fd KS |
122 | static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); |
123 | static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store); | |
12633e80 NF |
124 | #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ |
125 | ||
1da177e4 LT |
126 | #else /* ... !CONFIG_HOTPLUG_CPU */ |
127 | static inline void register_cpu_control(struct cpu *cpu) | |
128 | { | |
129 | } | |
130 | #endif /* CONFIG_HOTPLUG_CPU */ | |
131 | ||
51be5606 VG |
132 | #ifdef CONFIG_KEXEC |
133 | #include <linux/kexec.h> | |
134 | ||
8a25a2fd | 135 | static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr, |
4a0b2b4d | 136 | char *buf) |
51be5606 | 137 | { |
8a25a2fd | 138 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
51be5606 VG |
139 | ssize_t rc; |
140 | unsigned long long addr; | |
141 | int cpunum; | |
142 | ||
8a25a2fd | 143 | cpunum = cpu->dev.id; |
51be5606 VG |
144 | |
145 | /* | |
146 | * Might be reading other cpu's data based on which cpu read thread | |
147 | * has been scheduled. But cpu data (memory) is allocated once during | |
148 | * boot up and this data does not change there after. Hence this | |
149 | * operation should be safe. No locking required. | |
150 | */ | |
3b034b0d | 151 | addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum)); |
51be5606 | 152 | rc = sprintf(buf, "%Lx\n", addr); |
51be5606 VG |
153 | return rc; |
154 | } | |
8a25a2fd | 155 | static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL); |
eca4549f ZY |
156 | |
157 | static ssize_t show_crash_notes_size(struct device *dev, | |
158 | struct device_attribute *attr, | |
159 | char *buf) | |
160 | { | |
161 | ssize_t rc; | |
162 | ||
bcfb87fb | 163 | rc = sprintf(buf, "%zu\n", sizeof(note_buf_t)); |
eca4549f ZY |
164 | return rc; |
165 | } | |
166 | static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL); | |
c055da9f IM |
167 | |
168 | static struct attribute *crash_note_cpu_attrs[] = { | |
169 | &dev_attr_crash_notes.attr, | |
170 | &dev_attr_crash_notes_size.attr, | |
171 | NULL | |
172 | }; | |
173 | ||
174 | static struct attribute_group crash_note_cpu_attr_group = { | |
175 | .attrs = crash_note_cpu_attrs, | |
176 | }; | |
177 | #endif | |
178 | ||
179 | static const struct attribute_group *common_cpu_attr_groups[] = { | |
180 | #ifdef CONFIG_KEXEC | |
181 | &crash_note_cpu_attr_group, | |
51be5606 | 182 | #endif |
c055da9f IM |
183 | NULL |
184 | }; | |
51be5606 | 185 | |
9d1fe323 MT |
186 | /* |
187 | * Print cpu online, possible, present, and system maps | |
188 | */ | |
265d2e2e AK |
189 | |
190 | struct cpu_attr { | |
8a25a2fd | 191 | struct device_attribute attr; |
265d2e2e AK |
192 | const struct cpumask *const * const map; |
193 | }; | |
194 | ||
8a25a2fd KS |
195 | static ssize_t show_cpus_attr(struct device *dev, |
196 | struct device_attribute *attr, | |
265d2e2e | 197 | char *buf) |
9d1fe323 | 198 | { |
265d2e2e AK |
199 | struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr); |
200 | int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map)); | |
9d1fe323 MT |
201 | |
202 | buf[n++] = '\n'; | |
203 | buf[n] = '\0'; | |
204 | return n; | |
205 | } | |
206 | ||
8a25a2fd KS |
207 | #define _CPU_ATTR(name, map) \ |
208 | { __ATTR(name, 0444, show_cpus_attr, NULL), map } | |
9d1fe323 | 209 | |
8a25a2fd | 210 | /* Keep in sync with cpu_subsys_attrs */ |
265d2e2e AK |
211 | static struct cpu_attr cpu_attrs[] = { |
212 | _CPU_ATTR(online, &cpu_online_mask), | |
213 | _CPU_ATTR(possible, &cpu_possible_mask), | |
214 | _CPU_ATTR(present, &cpu_present_mask), | |
215 | }; | |
9d1fe323 | 216 | |
e057d7ae MT |
217 | /* |
218 | * Print values for NR_CPUS and offlined cpus | |
219 | */ | |
8a25a2fd KS |
220 | static ssize_t print_cpus_kernel_max(struct device *dev, |
221 | struct device_attribute *attr, char *buf) | |
e057d7ae | 222 | { |
8fd2d2d5 | 223 | int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1); |
e057d7ae MT |
224 | return n; |
225 | } | |
8a25a2fd | 226 | static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); |
e057d7ae MT |
227 | |
228 | /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */ | |
229 | unsigned int total_cpus; | |
230 | ||
8a25a2fd KS |
231 | static ssize_t print_cpus_offline(struct device *dev, |
232 | struct device_attribute *attr, char *buf) | |
e057d7ae MT |
233 | { |
234 | int n = 0, len = PAGE_SIZE-2; | |
235 | cpumask_var_t offline; | |
236 | ||
237 | /* display offline cpus < nr_cpu_ids */ | |
238 | if (!alloc_cpumask_var(&offline, GFP_KERNEL)) | |
239 | return -ENOMEM; | |
cdc6e3d3 | 240 | cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask); |
e057d7ae MT |
241 | n = cpulist_scnprintf(buf, len, offline); |
242 | free_cpumask_var(offline); | |
243 | ||
244 | /* display offline cpus >= nr_cpu_ids */ | |
245 | if (total_cpus && nr_cpu_ids < total_cpus) { | |
246 | if (n && n < len) | |
247 | buf[n++] = ','; | |
248 | ||
249 | if (nr_cpu_ids == total_cpus-1) | |
250 | n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids); | |
251 | else | |
252 | n += snprintf(&buf[n], len - n, "%d-%d", | |
253 | nr_cpu_ids, total_cpus-1); | |
254 | } | |
255 | ||
256 | n += snprintf(&buf[n], len - n, "\n"); | |
257 | return n; | |
258 | } | |
8a25a2fd | 259 | static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); |
e057d7ae | 260 | |
2885e25c GKH |
261 | static void cpu_device_release(struct device *dev) |
262 | { | |
263 | /* | |
264 | * This is an empty function to prevent the driver core from spitting a | |
265 | * warning at us. Yes, I know this is directly opposite of what the | |
266 | * documentation for the driver core and kobjects say, and the author | |
267 | * of this code has already been publically ridiculed for doing | |
268 | * something as foolish as this. However, at this point in time, it is | |
269 | * the only way to handle the issue of statically allocated cpu | |
270 | * devices. The different architectures will have their cpu device | |
271 | * code reworked to properly handle this in the near future, so this | |
272 | * function will then be changed to correctly free up the memory held | |
273 | * by the cpu device. | |
274 | * | |
275 | * Never copy this way of doing things, or you too will be made fun of | |
30a4840a | 276 | * on the linux-kernel list, you have been warned. |
2885e25c GKH |
277 | */ |
278 | } | |
279 | ||
1da177e4 | 280 | /* |
405ae7d3 | 281 | * register_cpu - Setup a sysfs device for a CPU. |
72486f1f SS |
282 | * @cpu - cpu->hotpluggable field set to 1 will generate a control file in |
283 | * sysfs for this CPU. | |
1da177e4 LT |
284 | * @num - CPU number to use when creating the device. |
285 | * | |
286 | * Initialize and register the CPU device. | |
287 | */ | |
33b5f31b | 288 | int __cpuinit register_cpu(struct cpu *cpu, int num) |
1da177e4 LT |
289 | { |
290 | int error; | |
76b67ed9 | 291 | |
8a25a2fd | 292 | cpu->node_id = cpu_to_node(num); |
29bb5d4f | 293 | memset(&cpu->dev, 0x00, sizeof(struct device)); |
8a25a2fd KS |
294 | cpu->dev.id = num; |
295 | cpu->dev.bus = &cpu_subsys; | |
2885e25c | 296 | cpu->dev.release = cpu_device_release; |
fad12ac8 TR |
297 | #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE |
298 | cpu->dev.bus->uevent = arch_cpu_uevent; | |
299 | #endif | |
c055da9f | 300 | cpu->dev.groups = common_cpu_attr_groups; |
8a25a2fd | 301 | error = device_register(&cpu->dev); |
72486f1f | 302 | if (!error && cpu->hotpluggable) |
1da177e4 | 303 | register_cpu_control(cpu); |
ad74557a | 304 | if (!error) |
8a25a2fd | 305 | per_cpu(cpu_sys_devices, num) = &cpu->dev; |
76b67ed9 KH |
306 | if (!error) |
307 | register_cpu_under_node(num, cpu_to_node(num)); | |
51be5606 | 308 | |
1da177e4 LT |
309 | return error; |
310 | } | |
311 | ||
8a25a2fd | 312 | struct device *get_cpu_device(unsigned cpu) |
ad74557a | 313 | { |
e37d05da MT |
314 | if (cpu < nr_cpu_ids && cpu_possible(cpu)) |
315 | return per_cpu(cpu_sys_devices, cpu); | |
ad74557a AR |
316 | else |
317 | return NULL; | |
318 | } | |
8a25a2fd KS |
319 | EXPORT_SYMBOL_GPL(get_cpu_device); |
320 | ||
fad12ac8 TR |
321 | #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE |
322 | static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL); | |
323 | #endif | |
324 | ||
8a25a2fd KS |
325 | static struct attribute *cpu_root_attrs[] = { |
326 | #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE | |
327 | &dev_attr_probe.attr, | |
328 | &dev_attr_release.attr, | |
329 | #endif | |
330 | &cpu_attrs[0].attr.attr, | |
331 | &cpu_attrs[1].attr.attr, | |
332 | &cpu_attrs[2].attr.attr, | |
333 | &dev_attr_kernel_max.attr, | |
334 | &dev_attr_offline.attr, | |
fad12ac8 TR |
335 | #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE |
336 | &dev_attr_modalias.attr, | |
337 | #endif | |
8a25a2fd KS |
338 | NULL |
339 | }; | |
340 | ||
341 | static struct attribute_group cpu_root_attr_group = { | |
342 | .attrs = cpu_root_attrs, | |
343 | }; | |
344 | ||
345 | static const struct attribute_group *cpu_root_attr_groups[] = { | |
346 | &cpu_root_attr_group, | |
347 | NULL, | |
348 | }; | |
1da177e4 | 349 | |
2987557f JT |
350 | bool cpu_is_hotpluggable(unsigned cpu) |
351 | { | |
7affca35 LT |
352 | struct device *dev = get_cpu_device(cpu); |
353 | return dev && container_of(dev, struct cpu, dev)->hotpluggable; | |
2987557f JT |
354 | } |
355 | EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); | |
356 | ||
9f13a1fd BH |
357 | #ifdef CONFIG_GENERIC_CPU_DEVICES |
358 | static DEFINE_PER_CPU(struct cpu, cpu_devices); | |
359 | #endif | |
360 | ||
361 | static void __init cpu_dev_register_generic(void) | |
362 | { | |
363 | #ifdef CONFIG_GENERIC_CPU_DEVICES | |
364 | int i; | |
365 | ||
366 | for_each_possible_cpu(i) { | |
367 | if (register_cpu(&per_cpu(cpu_devices, i), i)) | |
368 | panic("Failed to register CPU device"); | |
369 | } | |
370 | #endif | |
371 | } | |
372 | ||
024f7846 | 373 | void __init cpu_dev_init(void) |
1da177e4 | 374 | { |
024f7846 BH |
375 | if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups)) |
376 | panic("Failed to register CPU subsystem"); | |
8a25a2fd | 377 | |
9f13a1fd | 378 | cpu_dev_register_generic(); |
1da177e4 | 379 | } |