Commit | Line | Data |
---|---|---|
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> |
ac212b69 | 16 | #include <linux/acpi.h> |
1da177e4 | 17 | |
a1bdc7aa | 18 | #include "base.h" |
1da177e4 | 19 | |
8a25a2fd | 20 | static DEFINE_PER_CPU(struct device *, cpu_sys_devices); |
ad74557a | 21 | |
ac212b69 RW |
22 | static int cpu_subsys_match(struct device *dev, struct device_driver *drv) |
23 | { | |
24 | /* ACPI style match is the only one that may succeed. */ | |
25 | if (acpi_driver_match_device(dev, drv)) | |
26 | return 1; | |
27 | ||
28 | return 0; | |
29 | } | |
30 | ||
1da177e4 | 31 | #ifdef CONFIG_HOTPLUG_CPU |
34640468 YI |
32 | static void change_cpu_under_node(struct cpu *cpu, |
33 | unsigned int from_nid, unsigned int to_nid) | |
34 | { | |
35 | int cpuid = cpu->dev.id; | |
36 | unregister_cpu_under_node(cpuid, from_nid); | |
37 | register_cpu_under_node(cpuid, to_nid); | |
38 | cpu->node_id = to_nid; | |
39 | } | |
40 | ||
0902a904 | 41 | static int __ref cpu_subsys_online(struct device *dev) |
1da177e4 | 42 | { |
8a25a2fd | 43 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
0902a904 RW |
44 | int cpuid = dev->id; |
45 | int from_nid, to_nid; | |
46 | int ret; | |
47 | ||
48 | cpu_hotplug_driver_lock(); | |
49 | ||
50 | from_nid = cpu_to_node(cpuid); | |
51 | ret = cpu_up(cpuid); | |
52 | /* | |
53 | * When hot adding memory to memoryless node and enabling a cpu | |
54 | * on the node, node number of the cpu may internally change. | |
55 | */ | |
56 | to_nid = cpu_to_node(cpuid); | |
57 | if (from_nid != to_nid) | |
58 | change_cpu_under_node(cpu, from_nid, to_nid); | |
1da177e4 | 59 | |
0902a904 RW |
60 | cpu_hotplug_driver_unlock(); |
61 | return ret; | |
1da177e4 LT |
62 | } |
63 | ||
0902a904 | 64 | static int cpu_subsys_offline(struct device *dev) |
1da177e4 | 65 | { |
0902a904 | 66 | int ret; |
1da177e4 | 67 | |
51badebd | 68 | cpu_hotplug_driver_lock(); |
0902a904 | 69 | ret = cpu_down(dev->id); |
51badebd | 70 | cpu_hotplug_driver_unlock(); |
1da177e4 LT |
71 | return ret; |
72 | } | |
1da177e4 | 73 | |
76b67ed9 | 74 | void unregister_cpu(struct cpu *cpu) |
1da177e4 | 75 | { |
8a25a2fd | 76 | int logical_cpu = cpu->dev.id; |
1da177e4 | 77 | |
76b67ed9 KH |
78 | unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu)); |
79 | ||
8a25a2fd | 80 | device_unregister(&cpu->dev); |
e37d05da | 81 | per_cpu(cpu_sys_devices, logical_cpu) = NULL; |
1da177e4 LT |
82 | return; |
83 | } | |
12633e80 NF |
84 | |
85 | #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE | |
8a25a2fd KS |
86 | static ssize_t cpu_probe_store(struct device *dev, |
87 | struct device_attribute *attr, | |
67fc233f | 88 | const char *buf, |
12633e80 NF |
89 | size_t count) |
90 | { | |
91 | return arch_cpu_probe(buf, count); | |
92 | } | |
93 | ||
8a25a2fd KS |
94 | static ssize_t cpu_release_store(struct device *dev, |
95 | struct device_attribute *attr, | |
67fc233f | 96 | const char *buf, |
12633e80 NF |
97 | size_t count) |
98 | { | |
99 | return arch_cpu_release(buf, count); | |
100 | } | |
101 | ||
8a25a2fd KS |
102 | static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store); |
103 | static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store); | |
12633e80 NF |
104 | #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */ |
105 | ||
1da177e4 LT |
106 | #endif /* CONFIG_HOTPLUG_CPU */ |
107 | ||
0902a904 RW |
108 | struct bus_type cpu_subsys = { |
109 | .name = "cpu", | |
110 | .dev_name = "cpu", | |
ac212b69 | 111 | .match = cpu_subsys_match, |
0902a904 RW |
112 | #ifdef CONFIG_HOTPLUG_CPU |
113 | .online = cpu_subsys_online, | |
114 | .offline = cpu_subsys_offline, | |
115 | #endif | |
116 | }; | |
117 | EXPORT_SYMBOL_GPL(cpu_subsys); | |
118 | ||
51be5606 VG |
119 | #ifdef CONFIG_KEXEC |
120 | #include <linux/kexec.h> | |
121 | ||
8a25a2fd | 122 | static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr, |
4a0b2b4d | 123 | char *buf) |
51be5606 | 124 | { |
8a25a2fd | 125 | struct cpu *cpu = container_of(dev, struct cpu, dev); |
51be5606 VG |
126 | ssize_t rc; |
127 | unsigned long long addr; | |
128 | int cpunum; | |
129 | ||
8a25a2fd | 130 | cpunum = cpu->dev.id; |
51be5606 VG |
131 | |
132 | /* | |
133 | * Might be reading other cpu's data based on which cpu read thread | |
134 | * has been scheduled. But cpu data (memory) is allocated once during | |
135 | * boot up and this data does not change there after. Hence this | |
136 | * operation should be safe. No locking required. | |
137 | */ | |
3b034b0d | 138 | addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum)); |
51be5606 | 139 | rc = sprintf(buf, "%Lx\n", addr); |
51be5606 VG |
140 | return rc; |
141 | } | |
8a25a2fd | 142 | static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL); |
eca4549f ZY |
143 | |
144 | static ssize_t show_crash_notes_size(struct device *dev, | |
145 | struct device_attribute *attr, | |
146 | char *buf) | |
147 | { | |
148 | ssize_t rc; | |
149 | ||
bcfb87fb | 150 | rc = sprintf(buf, "%zu\n", sizeof(note_buf_t)); |
eca4549f ZY |
151 | return rc; |
152 | } | |
153 | static DEVICE_ATTR(crash_notes_size, 0400, show_crash_notes_size, NULL); | |
51be5606 VG |
154 | #endif |
155 | ||
9d1fe323 MT |
156 | /* |
157 | * Print cpu online, possible, present, and system maps | |
158 | */ | |
265d2e2e AK |
159 | |
160 | struct cpu_attr { | |
8a25a2fd | 161 | struct device_attribute attr; |
265d2e2e AK |
162 | const struct cpumask *const * const map; |
163 | }; | |
164 | ||
8a25a2fd KS |
165 | static ssize_t show_cpus_attr(struct device *dev, |
166 | struct device_attribute *attr, | |
265d2e2e | 167 | char *buf) |
9d1fe323 | 168 | { |
265d2e2e AK |
169 | struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr); |
170 | int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map)); | |
9d1fe323 MT |
171 | |
172 | buf[n++] = '\n'; | |
173 | buf[n] = '\0'; | |
174 | return n; | |
175 | } | |
176 | ||
8a25a2fd KS |
177 | #define _CPU_ATTR(name, map) \ |
178 | { __ATTR(name, 0444, show_cpus_attr, NULL), map } | |
9d1fe323 | 179 | |
8a25a2fd | 180 | /* Keep in sync with cpu_subsys_attrs */ |
265d2e2e AK |
181 | static struct cpu_attr cpu_attrs[] = { |
182 | _CPU_ATTR(online, &cpu_online_mask), | |
183 | _CPU_ATTR(possible, &cpu_possible_mask), | |
184 | _CPU_ATTR(present, &cpu_present_mask), | |
185 | }; | |
9d1fe323 | 186 | |
e057d7ae MT |
187 | /* |
188 | * Print values for NR_CPUS and offlined cpus | |
189 | */ | |
8a25a2fd KS |
190 | static ssize_t print_cpus_kernel_max(struct device *dev, |
191 | struct device_attribute *attr, char *buf) | |
e057d7ae | 192 | { |
8fd2d2d5 | 193 | int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1); |
e057d7ae MT |
194 | return n; |
195 | } | |
8a25a2fd | 196 | static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL); |
e057d7ae MT |
197 | |
198 | /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */ | |
199 | unsigned int total_cpus; | |
200 | ||
8a25a2fd KS |
201 | static ssize_t print_cpus_offline(struct device *dev, |
202 | struct device_attribute *attr, char *buf) | |
e057d7ae MT |
203 | { |
204 | int n = 0, len = PAGE_SIZE-2; | |
205 | cpumask_var_t offline; | |
206 | ||
207 | /* display offline cpus < nr_cpu_ids */ | |
208 | if (!alloc_cpumask_var(&offline, GFP_KERNEL)) | |
209 | return -ENOMEM; | |
cdc6e3d3 | 210 | cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask); |
e057d7ae MT |
211 | n = cpulist_scnprintf(buf, len, offline); |
212 | free_cpumask_var(offline); | |
213 | ||
214 | /* display offline cpus >= nr_cpu_ids */ | |
215 | if (total_cpus && nr_cpu_ids < total_cpus) { | |
216 | if (n && n < len) | |
217 | buf[n++] = ','; | |
218 | ||
219 | if (nr_cpu_ids == total_cpus-1) | |
220 | n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids); | |
221 | else | |
222 | n += snprintf(&buf[n], len - n, "%d-%d", | |
223 | nr_cpu_ids, total_cpus-1); | |
224 | } | |
225 | ||
226 | n += snprintf(&buf[n], len - n, "\n"); | |
227 | return n; | |
228 | } | |
8a25a2fd | 229 | static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL); |
e057d7ae | 230 | |
2885e25c GKH |
231 | static void cpu_device_release(struct device *dev) |
232 | { | |
233 | /* | |
234 | * This is an empty function to prevent the driver core from spitting a | |
235 | * warning at us. Yes, I know this is directly opposite of what the | |
236 | * documentation for the driver core and kobjects say, and the author | |
237 | * of this code has already been publically ridiculed for doing | |
238 | * something as foolish as this. However, at this point in time, it is | |
239 | * the only way to handle the issue of statically allocated cpu | |
240 | * devices. The different architectures will have their cpu device | |
241 | * code reworked to properly handle this in the near future, so this | |
242 | * function will then be changed to correctly free up the memory held | |
243 | * by the cpu device. | |
244 | * | |
245 | * Never copy this way of doing things, or you too will be made fun of | |
30a4840a | 246 | * on the linux-kernel list, you have been warned. |
2885e25c GKH |
247 | */ |
248 | } | |
249 | ||
1da177e4 | 250 | /* |
405ae7d3 | 251 | * register_cpu - Setup a sysfs device for a CPU. |
72486f1f SS |
252 | * @cpu - cpu->hotpluggable field set to 1 will generate a control file in |
253 | * sysfs for this CPU. | |
1da177e4 LT |
254 | * @num - CPU number to use when creating the device. |
255 | * | |
256 | * Initialize and register the CPU device. | |
257 | */ | |
33b5f31b | 258 | int __cpuinit register_cpu(struct cpu *cpu, int num) |
1da177e4 LT |
259 | { |
260 | int error; | |
76b67ed9 | 261 | |
8a25a2fd | 262 | cpu->node_id = cpu_to_node(num); |
29bb5d4f | 263 | memset(&cpu->dev, 0x00, sizeof(struct device)); |
8a25a2fd KS |
264 | cpu->dev.id = num; |
265 | cpu->dev.bus = &cpu_subsys; | |
2885e25c | 266 | cpu->dev.release = cpu_device_release; |
0902a904 | 267 | cpu->dev.offline_disabled = !cpu->hotpluggable; |
fad12ac8 TR |
268 | #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE |
269 | cpu->dev.bus->uevent = arch_cpu_uevent; | |
270 | #endif | |
8a25a2fd | 271 | error = device_register(&cpu->dev); |
ad74557a | 272 | if (!error) |
8a25a2fd | 273 | per_cpu(cpu_sys_devices, num) = &cpu->dev; |
76b67ed9 KH |
274 | if (!error) |
275 | register_cpu_under_node(num, cpu_to_node(num)); | |
51be5606 VG |
276 | |
277 | #ifdef CONFIG_KEXEC | |
278 | if (!error) | |
8a25a2fd | 279 | error = device_create_file(&cpu->dev, &dev_attr_crash_notes); |
eca4549f ZY |
280 | if (!error) |
281 | error = device_create_file(&cpu->dev, | |
282 | &dev_attr_crash_notes_size); | |
51be5606 | 283 | #endif |
1da177e4 LT |
284 | return error; |
285 | } | |
286 | ||
8a25a2fd | 287 | struct device *get_cpu_device(unsigned cpu) |
ad74557a | 288 | { |
e37d05da MT |
289 | if (cpu < nr_cpu_ids && cpu_possible(cpu)) |
290 | return per_cpu(cpu_sys_devices, cpu); | |
ad74557a AR |
291 | else |
292 | return NULL; | |
293 | } | |
8a25a2fd KS |
294 | EXPORT_SYMBOL_GPL(get_cpu_device); |
295 | ||
fad12ac8 TR |
296 | #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE |
297 | static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL); | |
298 | #endif | |
299 | ||
8a25a2fd KS |
300 | static struct attribute *cpu_root_attrs[] = { |
301 | #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE | |
302 | &dev_attr_probe.attr, | |
303 | &dev_attr_release.attr, | |
304 | #endif | |
305 | &cpu_attrs[0].attr.attr, | |
306 | &cpu_attrs[1].attr.attr, | |
307 | &cpu_attrs[2].attr.attr, | |
308 | &dev_attr_kernel_max.attr, | |
309 | &dev_attr_offline.attr, | |
fad12ac8 TR |
310 | #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE |
311 | &dev_attr_modalias.attr, | |
312 | #endif | |
8a25a2fd KS |
313 | NULL |
314 | }; | |
315 | ||
316 | static struct attribute_group cpu_root_attr_group = { | |
317 | .attrs = cpu_root_attrs, | |
318 | }; | |
319 | ||
320 | static const struct attribute_group *cpu_root_attr_groups[] = { | |
321 | &cpu_root_attr_group, | |
322 | NULL, | |
323 | }; | |
1da177e4 | 324 | |
2987557f JT |
325 | bool cpu_is_hotpluggable(unsigned cpu) |
326 | { | |
7affca35 LT |
327 | struct device *dev = get_cpu_device(cpu); |
328 | return dev && container_of(dev, struct cpu, dev)->hotpluggable; | |
2987557f JT |
329 | } |
330 | EXPORT_SYMBOL_GPL(cpu_is_hotpluggable); | |
331 | ||
9f13a1fd BH |
332 | #ifdef CONFIG_GENERIC_CPU_DEVICES |
333 | static DEFINE_PER_CPU(struct cpu, cpu_devices); | |
334 | #endif | |
335 | ||
336 | static void __init cpu_dev_register_generic(void) | |
337 | { | |
338 | #ifdef CONFIG_GENERIC_CPU_DEVICES | |
339 | int i; | |
340 | ||
341 | for_each_possible_cpu(i) { | |
342 | if (register_cpu(&per_cpu(cpu_devices, i), i)) | |
343 | panic("Failed to register CPU device"); | |
344 | } | |
345 | #endif | |
346 | } | |
347 | ||
024f7846 | 348 | void __init cpu_dev_init(void) |
1da177e4 | 349 | { |
024f7846 BH |
350 | if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups)) |
351 | panic("Failed to register CPU subsystem"); | |
8a25a2fd | 352 | |
9f13a1fd | 353 | cpu_dev_register_generic(); |
1da177e4 | 354 | } |