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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> |
9f13a1fd | 14 | #include <linux/percpu.h> |
1da177e4 | 15 | |
a1bdc7aa | 16 | #include "base.h" |
1da177e4 | 17 | |
8a25a2fd | 18 | struct bus_type cpu_subsys = { |
af5ca3f4 | 19 | .name = "cpu", |
8a25a2fd | 20 | .dev_name = "cpu", |
1da177e4 | 21 | }; |
8a25a2fd | 22 | EXPORT_SYMBOL_GPL(cpu_subsys); |
1da177e4 | 23 | |
8a25a2fd | 24 | static DEFINE_PER_CPU(struct device *, cpu_sys_devices); |
ad74557a | 25 | |
1da177e4 | 26 | #ifdef CONFIG_HOTPLUG_CPU |
8a25a2fd KS |
27 | static ssize_t show_online(struct device *dev, |
28 | struct device_attribute *attr, | |
4a0b2b4d | 29 | char *buf) |
1da177e4 | 30 | { |
8a25a2fd | 31 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
1da177e4 | 32 | |
8a25a2fd | 33 | return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id)); |
1da177e4 LT |
34 | } |
35 | ||
8a25a2fd KS |
36 | static ssize_t __ref store_online(struct device *dev, |
37 | struct device_attribute *attr, | |
38 | const char *buf, size_t count) | |
1da177e4 | 39 | { |
8a25a2fd | 40 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
1da177e4 LT |
41 | ssize_t ret; |
42 | ||
51badebd | 43 | cpu_hotplug_driver_lock(); |
1da177e4 LT |
44 | switch (buf[0]) { |
45 | case '0': | |
8a25a2fd | 46 | ret = cpu_down(cpu->dev.id); |
1da177e4 | 47 | if (!ret) |
312c004d | 48 | kobject_uevent(&dev->kobj, KOBJ_OFFLINE); |
1da177e4 LT |
49 | break; |
50 | case '1': | |
8a25a2fd | 51 | ret = cpu_up(cpu->dev.id); |
fb69c390 | 52 | if (!ret) |
312c004d | 53 | kobject_uevent(&dev->kobj, KOBJ_ONLINE); |
1da177e4 LT |
54 | break; |
55 | default: | |
56 | ret = -EINVAL; | |
57 | } | |
51badebd | 58 | cpu_hotplug_driver_unlock(); |
1da177e4 LT |
59 | |
60 | if (ret >= 0) | |
61 | ret = count; | |
62 | return ret; | |
63 | } | |
8a25a2fd | 64 | static DEVICE_ATTR(online, 0644, show_online, store_online); |
1da177e4 | 65 | |
6c847402 | 66 | static void __cpuinit register_cpu_control(struct cpu *cpu) |
1da177e4 | 67 | { |
8a25a2fd | 68 | device_create_file(&cpu->dev, &dev_attr_online); |
1da177e4 | 69 | } |
76b67ed9 | 70 | void unregister_cpu(struct cpu *cpu) |
1da177e4 | 71 | { |
8a25a2fd | 72 | int logical_cpu = cpu->dev.id; |
1da177e4 | 73 | |
76b67ed9 KH |
74 | unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); |
75 | ||
8a25a2fd | 76 | device_remove_file(&cpu->dev, &dev_attr_online); |
1da177e4 | 77 | |
8a25a2fd | 78 | device_unregister(&cpu->dev); |
e37d05da | 79 | per_cpu(cpu_sys_devices, logical_cpu) = NULL; |
1da177e4 LT |
80 | return; |
81 | } | |
12633e80 NF |
82 | |
83 | #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE | |
8a25a2fd KS |
84 | static ssize_t cpu_probe_store(struct device *dev, |
85 | struct device_attribute *attr, | |
67fc233f | 86 | const char *buf, |
12633e80 NF |
87 | size_t count) |
88 | { | |
89 | return arch_cpu_probe(buf, count); | |
90 | } | |
91 | ||
8a25a2fd KS |
92 | static ssize_t cpu_release_store(struct device *dev, |
93 | struct device_attribute *attr, | |
67fc233f | 94 | const char *buf, |
12633e80 NF |
95 | size_t count) |
96 | { | |
97 | return arch_cpu_release(buf, count); | |
98 | } | |
99 | ||
8a25a2fd KS |
100 | static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); |
101 | static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store); | |
12633e80 NF |
102 | #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ |
103 | ||
1da177e4 LT |
104 | #else /* ... !CONFIG_HOTPLUG_CPU */ |
105 | static inline void register_cpu_control(struct cpu *cpu) | |
106 | { | |
107 | } | |
108 | #endif /* CONFIG_HOTPLUG_CPU */ | |
109 | ||
51be5606 VG |
110 | #ifdef CONFIG_KEXEC |
111 | #include <linux/kexec.h> | |
112 | ||
8a25a2fd | 113 | static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr, |
4a0b2b4d | 114 | char *buf) |
51be5606 | 115 | { |
8a25a2fd | 116 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
51be5606 VG |
117 | ssize_t rc; |
118 | unsigned long long addr; | |
119 | int cpunum; | |
120 | ||
8a25a2fd | 121 | cpunum = cpu->dev.id; |
51be5606 VG |
122 | |
123 | /* | |
124 | * Might be reading other cpu's data based on which cpu read thread | |
125 | * has been scheduled. But cpu data (memory) is allocated once during | |
126 | * boot up and this data does not change there after. Hence this | |
127 | * operation should be safe. No locking required. | |
128 | */ | |
3b034b0d | 129 | addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum)); |
51be5606 | 130 | rc = sprintf(buf, "%Lx\n", addr); |
51be5606 VG |
131 | return rc; |
132 | } | |
8a25a2fd | 133 | static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL); |
51be5606 VG |
134 | #endif |
135 | ||
9d1fe323 MT |
136 | /* |
137 | * Print cpu online, possible, present, and system maps | |
138 | */ | |
265d2e2e AK |
139 | |
140 | struct cpu_attr { | |
8a25a2fd | 141 | struct device_attribute attr; |
265d2e2e AK |
142 | const struct cpumask *const * const map; |
143 | }; | |
144 | ||
8a25a2fd KS |
145 | static ssize_t show_cpus_attr(struct device *dev, |
146 | struct device_attribute *attr, | |
265d2e2e | 147 | char *buf) |
9d1fe323 | 148 | { |
265d2e2e AK |
149 | struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr); |
150 | int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map)); | |
9d1fe323 MT |
151 | |
152 | buf[n++] = '\n'; | |
153 | buf[n] = '\0'; | |
154 | return n; | |
155 | } | |
156 | ||
8a25a2fd KS |
157 | #define _CPU_ATTR(name, map) \ |
158 | { __ATTR(name, 0444, show_cpus_attr, NULL), map } | |
9d1fe323 | 159 | |
8a25a2fd | 160 | /* Keep in sync with cpu_subsys_attrs */ |
265d2e2e AK |
161 | static struct cpu_attr cpu_attrs[] = { |
162 | _CPU_ATTR(online, &cpu_online_mask), | |
163 | _CPU_ATTR(possible, &cpu_possible_mask), | |
164 | _CPU_ATTR(present, &cpu_present_mask), | |
165 | }; | |
9d1fe323 | 166 | |
e057d7ae MT |
167 | /* |
168 | * Print values for NR_CPUS and offlined cpus | |
169 | */ | |
8a25a2fd KS |
170 | static ssize_t print_cpus_kernel_max(struct device *dev, |
171 | struct device_attribute *attr, char *buf) | |
e057d7ae | 172 | { |
8fd2d2d5 | 173 | int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1); |
e057d7ae MT |
174 | return n; |
175 | } | |
8a25a2fd | 176 | static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); |
e057d7ae MT |
177 | |
178 | /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */ | |
179 | unsigned int total_cpus; | |
180 | ||
8a25a2fd KS |
181 | static ssize_t print_cpus_offline(struct device *dev, |
182 | struct device_attribute *attr, char *buf) | |
e057d7ae MT |
183 | { |
184 | int n = 0, len = PAGE_SIZE-2; | |
185 | cpumask_var_t offline; | |
186 | ||
187 | /* display offline cpus < nr_cpu_ids */ | |
188 | if (!alloc_cpumask_var(&offline, GFP_KERNEL)) | |
189 | return -ENOMEM; | |
cdc6e3d3 | 190 | cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask); |
e057d7ae MT |
191 | n = cpulist_scnprintf(buf, len, offline); |
192 | free_cpumask_var(offline); | |
193 | ||
194 | /* display offline cpus >= nr_cpu_ids */ | |
195 | if (total_cpus && nr_cpu_ids < total_cpus) { | |
196 | if (n && n < len) | |
197 | buf[n++] = ','; | |
198 | ||
199 | if (nr_cpu_ids == total_cpus-1) | |
200 | n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids); | |
201 | else | |
202 | n += snprintf(&buf[n], len - n, "%d-%d", | |
203 | nr_cpu_ids, total_cpus-1); | |
204 | } | |
205 | ||
206 | n += snprintf(&buf[n], len - n, "\n"); | |
207 | return n; | |
208 | } | |
8a25a2fd | 209 | static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); |
e057d7ae | 210 | |
2885e25c GKH |
211 | static void cpu_device_release(struct device *dev) |
212 | { | |
213 | /* | |
214 | * This is an empty function to prevent the driver core from spitting a | |
215 | * warning at us. Yes, I know this is directly opposite of what the | |
216 | * documentation for the driver core and kobjects say, and the author | |
217 | * of this code has already been publically ridiculed for doing | |
218 | * something as foolish as this. However, at this point in time, it is | |
219 | * the only way to handle the issue of statically allocated cpu | |
220 | * devices. The different architectures will have their cpu device | |
221 | * code reworked to properly handle this in the near future, so this | |
222 | * function will then be changed to correctly free up the memory held | |
223 | * by the cpu device. | |
224 | * | |
225 | * Never copy this way of doing things, or you too will be made fun of | |
226 | * on the linux-kerenl list, you have been warned. | |
227 | */ | |
228 | } | |
229 | ||
1da177e4 | 230 | /* |
405ae7d3 | 231 | * register_cpu - Setup a sysfs device for a CPU. |
72486f1f SS |
232 | * @cpu - cpu->hotpluggable field set to 1 will generate a control file in |
233 | * sysfs for this CPU. | |
1da177e4 LT |
234 | * @num - CPU number to use when creating the device. |
235 | * | |
236 | * Initialize and register the CPU device. | |
237 | */ | |
33b5f31b | 238 | int __cpuinit register_cpu(struct cpu *cpu, int num) |
1da177e4 LT |
239 | { |
240 | int error; | |
76b67ed9 | 241 | |
8a25a2fd KS |
242 | cpu->node_id = cpu_to_node(num); |
243 | cpu->dev.id = num; | |
244 | cpu->dev.bus = &cpu_subsys; | |
2885e25c | 245 | cpu->dev.release = cpu_device_release; |
8a25a2fd | 246 | error = device_register(&cpu->dev); |
72486f1f | 247 | if (!error && cpu->hotpluggable) |
1da177e4 | 248 | register_cpu_control(cpu); |
ad74557a | 249 | if (!error) |
8a25a2fd | 250 | per_cpu(cpu_sys_devices, num) = &cpu->dev; |
76b67ed9 KH |
251 | if (!error) |
252 | register_cpu_under_node(num, cpu_to_node(num)); | |
51be5606 VG |
253 | |
254 | #ifdef CONFIG_KEXEC | |
255 | if (!error) | |
8a25a2fd | 256 | error = device_create_file(&cpu->dev, &dev_attr_crash_notes); |
51be5606 | 257 | #endif |
1da177e4 LT |
258 | return error; |
259 | } | |
260 | ||
8a25a2fd | 261 | struct device *get_cpu_device(unsigned cpu) |
ad74557a | 262 | { |
e37d05da MT |
263 | if (cpu < nr_cpu_ids && cpu_possible(cpu)) |
264 | return per_cpu(cpu_sys_devices, cpu); | |
ad74557a AR |
265 | else |
266 | return NULL; | |
267 | } | |
8a25a2fd KS |
268 | EXPORT_SYMBOL_GPL(get_cpu_device); |
269 | ||
270 | static struct attribute *cpu_root_attrs[] = { | |
271 | #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE | |
272 | &dev_attr_probe.attr, | |
273 | &dev_attr_release.attr, | |
274 | #endif | |
275 | &cpu_attrs[0].attr.attr, | |
276 | &cpu_attrs[1].attr.attr, | |
277 | &cpu_attrs[2].attr.attr, | |
278 | &dev_attr_kernel_max.attr, | |
279 | &dev_attr_offline.attr, | |
280 | NULL | |
281 | }; | |
282 | ||
283 | static struct attribute_group cpu_root_attr_group = { | |
284 | .attrs = cpu_root_attrs, | |
285 | }; | |
286 | ||
287 | static const struct attribute_group *cpu_root_attr_groups[] = { | |
288 | &cpu_root_attr_group, | |
289 | NULL, | |
290 | }; | |
1da177e4 | 291 | |
2987557f JT |
292 | bool cpu_is_hotpluggable(unsigned cpu) |
293 | { | |
7affca35 LT |
294 | struct device *dev = get_cpu_device(cpu); |
295 | return dev && container_of(dev, struct cpu, dev)->hotpluggable; | |
2987557f JT |
296 | } |
297 | EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); | |
298 | ||
9f13a1fd BH |
299 | #ifdef CONFIG_GENERIC_CPU_DEVICES |
300 | static DEFINE_PER_CPU(struct cpu, cpu_devices); | |
301 | #endif | |
302 | ||
303 | static void __init cpu_dev_register_generic(void) | |
304 | { | |
305 | #ifdef CONFIG_GENERIC_CPU_DEVICES | |
306 | int i; | |
307 | ||
308 | for_each_possible_cpu(i) { | |
309 | if (register_cpu(&per_cpu(cpu_devices, i), i)) | |
310 | panic("Failed to register CPU device"); | |
311 | } | |
312 | #endif | |
313 | } | |
314 | ||
024f7846 | 315 | void __init cpu_dev_init(void) |
1da177e4 | 316 | { |
024f7846 BH |
317 | if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups)) |
318 | panic("Failed to register CPU subsystem"); | |
8a25a2fd | 319 | |
9f13a1fd BH |
320 | cpu_dev_register_generic(); |
321 | ||
5c45bf27 | 322 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
024f7846 | 323 | sched_create_sysfs_power_savings_entries(cpu_subsys.dev_root); |
5c45bf27 | 324 | #endif |
1da177e4 | 325 | } |