PM / Runtime: Fix rpm_resume() return value for power.no_callbacks set
[linux-2.6.git] / drivers / base / cpu.c
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
17 #include "base.h"
18
19 struct bus_type cpu_subsys = {
20         .name = "cpu",
21         .dev_name = "cpu",
22 };
23 EXPORT_SYMBOL_GPL(cpu_subsys);
24
25 static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
26
27 #ifdef CONFIG_HOTPLUG_CPU
28 static ssize_t show_online(struct device *dev,
29                            struct device_attribute *attr,
30                            char *buf)
31 {
32         struct cpu *cpu = container_of(dev, struct cpu, dev);
33
34         return sprintf(buf, "%u\n", !!cpu_online(cpu->dev.id));
35 }
36
37 static ssize_t __ref store_online(struct device *dev,
38                                   struct device_attribute *attr,
39                                   const char *buf, size_t count)
40 {
41         struct cpu *cpu = container_of(dev, struct cpu, dev);
42         ssize_t ret;
43
44         cpu_hotplug_driver_lock();
45         switch (buf[0]) {
46         case '0':
47                 ret = cpu_down(cpu->dev.id);
48                 if (!ret)
49                         kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
50                 break;
51         case '1':
52                 ret = cpu_up(cpu->dev.id);
53                 if (!ret)
54                         kobject_uevent(&dev->kobj, KOBJ_ONLINE);
55                 break;
56         default:
57                 ret = -EINVAL;
58         }
59         cpu_hotplug_driver_unlock();
60
61         if (ret >= 0)
62                 ret = count;
63         return ret;
64 }
65 static DEVICE_ATTR(online, 0644, show_online, store_online);
66
67 static void __cpuinit register_cpu_control(struct cpu *cpu)
68 {
69         device_create_file(&cpu->dev, &dev_attr_online);
70 }
71 void 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_remove_file(&cpu->dev, &dev_attr_online);
78
79         device_unregister(&cpu->dev);
80         per_cpu(cpu_sys_devices, logical_cpu) = NULL;
81         return;
82 }
83
84 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
85 static ssize_t cpu_probe_store(struct device *dev,
86                                struct device_attribute *attr,
87                                const char *buf,
88                                size_t count)
89 {
90         return arch_cpu_probe(buf, count);
91 }
92
93 static ssize_t cpu_release_store(struct device *dev,
94                                  struct device_attribute *attr,
95                                  const char *buf,
96                                  size_t count)
97 {
98         return arch_cpu_release(buf, count);
99 }
100
101 static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
102 static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
103 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
104
105 #else /* ... !CONFIG_HOTPLUG_CPU */
106 static inline void register_cpu_control(struct cpu *cpu)
107 {
108 }
109 #endif /* CONFIG_HOTPLUG_CPU */
110
111 #ifdef CONFIG_KEXEC
112 #include <linux/kexec.h>
113
114 static ssize_t show_crash_notes(struct device *dev, struct device_attribute *attr,
115                                 char *buf)
116 {
117         struct cpu *cpu = container_of(dev, struct cpu, dev);
118         ssize_t rc;
119         unsigned long long addr;
120         int cpunum;
121
122         cpunum = cpu->dev.id;
123
124         /*
125          * Might be reading other cpu's data based on which cpu read thread
126          * has been scheduled. But cpu data (memory) is allocated once during
127          * boot up and this data does not change there after. Hence this
128          * operation should be safe. No locking required.
129          */
130         addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
131         rc = sprintf(buf, "%Lx\n", addr);
132         return rc;
133 }
134 static DEVICE_ATTR(crash_notes, 0400, show_crash_notes, NULL);
135 #endif
136
137 /*
138  * Print cpu online, possible, present, and system maps
139  */
140
141 struct cpu_attr {
142         struct device_attribute attr;
143         const struct cpumask *const * const map;
144 };
145
146 static ssize_t show_cpus_attr(struct device *dev,
147                               struct device_attribute *attr,
148                               char *buf)
149 {
150         struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
151         int n = cpulist_scnprintf(buf, PAGE_SIZE-2, *(ca->map));
152
153         buf[n++] = '\n';
154         buf[n] = '\0';
155         return n;
156 }
157
158 #define _CPU_ATTR(name, map) \
159         { __ATTR(name, 0444, show_cpus_attr, NULL), map }
160
161 /* Keep in sync with cpu_subsys_attrs */
162 static struct cpu_attr cpu_attrs[] = {
163         _CPU_ATTR(online, &cpu_online_mask),
164         _CPU_ATTR(possible, &cpu_possible_mask),
165         _CPU_ATTR(present, &cpu_present_mask),
166 };
167
168 /*
169  * Print values for NR_CPUS and offlined cpus
170  */
171 static ssize_t print_cpus_kernel_max(struct device *dev,
172                                      struct device_attribute *attr, char *buf)
173 {
174         int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
175         return n;
176 }
177 static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
178
179 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
180 unsigned int total_cpus;
181
182 static ssize_t print_cpus_offline(struct device *dev,
183                                   struct device_attribute *attr, char *buf)
184 {
185         int n = 0, len = PAGE_SIZE-2;
186         cpumask_var_t offline;
187
188         /* display offline cpus < nr_cpu_ids */
189         if (!alloc_cpumask_var(&offline, GFP_KERNEL))
190                 return -ENOMEM;
191         cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
192         n = cpulist_scnprintf(buf, len, offline);
193         free_cpumask_var(offline);
194
195         /* display offline cpus >= nr_cpu_ids */
196         if (total_cpus && nr_cpu_ids < total_cpus) {
197                 if (n && n < len)
198                         buf[n++] = ',';
199
200                 if (nr_cpu_ids == total_cpus-1)
201                         n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
202                 else
203                         n += snprintf(&buf[n], len - n, "%d-%d",
204                                                       nr_cpu_ids, total_cpus-1);
205         }
206
207         n += snprintf(&buf[n], len - n, "\n");
208         return n;
209 }
210 static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
211
212 static void cpu_device_release(struct device *dev)
213 {
214         /*
215          * This is an empty function to prevent the driver core from spitting a
216          * warning at us.  Yes, I know this is directly opposite of what the
217          * documentation for the driver core and kobjects say, and the author
218          * of this code has already been publically ridiculed for doing
219          * something as foolish as this.  However, at this point in time, it is
220          * the only way to handle the issue of statically allocated cpu
221          * devices.  The different architectures will have their cpu device
222          * code reworked to properly handle this in the near future, so this
223          * function will then be changed to correctly free up the memory held
224          * by the cpu device.
225          *
226          * Never copy this way of doing things, or you too will be made fun of
227          * on the linux-kerenl list, you have been warned.
228          */
229 }
230
231 /*
232  * register_cpu - Setup a sysfs device for a CPU.
233  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
234  *        sysfs for this CPU.
235  * @num - CPU number to use when creating the device.
236  *
237  * Initialize and register the CPU device.
238  */
239 int __cpuinit register_cpu(struct cpu *cpu, int num)
240 {
241         int error;
242
243         cpu->node_id = cpu_to_node(num);
244         memset(&cpu->dev, 0x00, sizeof(struct device));
245         cpu->dev.id = num;
246         cpu->dev.bus = &cpu_subsys;
247         cpu->dev.release = cpu_device_release;
248 #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
249         cpu->dev.bus->uevent = arch_cpu_uevent;
250 #endif
251         error = device_register(&cpu->dev);
252         if (!error && cpu->hotpluggable)
253                 register_cpu_control(cpu);
254         if (!error)
255                 per_cpu(cpu_sys_devices, num) = &cpu->dev;
256         if (!error)
257                 register_cpu_under_node(num, cpu_to_node(num));
258
259 #ifdef CONFIG_KEXEC
260         if (!error)
261                 error = device_create_file(&cpu->dev, &dev_attr_crash_notes);
262 #endif
263         return error;
264 }
265
266 struct device *get_cpu_device(unsigned cpu)
267 {
268         if (cpu < nr_cpu_ids && cpu_possible(cpu))
269                 return per_cpu(cpu_sys_devices, cpu);
270         else
271                 return NULL;
272 }
273 EXPORT_SYMBOL_GPL(get_cpu_device);
274
275 #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
276 static DEVICE_ATTR(modalias, 0444, arch_print_cpu_modalias, NULL);
277 #endif
278
279 static struct attribute *cpu_root_attrs[] = {
280 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
281         &dev_attr_probe.attr,
282         &dev_attr_release.attr,
283 #endif
284         &cpu_attrs[0].attr.attr,
285         &cpu_attrs[1].attr.attr,
286         &cpu_attrs[2].attr.attr,
287         &dev_attr_kernel_max.attr,
288         &dev_attr_offline.attr,
289 #ifdef CONFIG_ARCH_HAS_CPU_AUTOPROBE
290         &dev_attr_modalias.attr,
291 #endif
292         NULL
293 };
294
295 static struct attribute_group cpu_root_attr_group = {
296         .attrs = cpu_root_attrs,
297 };
298
299 static const struct attribute_group *cpu_root_attr_groups[] = {
300         &cpu_root_attr_group,
301         NULL,
302 };
303
304 bool cpu_is_hotpluggable(unsigned cpu)
305 {
306         struct device *dev = get_cpu_device(cpu);
307         return dev && container_of(dev, struct cpu, dev)->hotpluggable;
308 }
309 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
310
311 #ifdef CONFIG_GENERIC_CPU_DEVICES
312 static DEFINE_PER_CPU(struct cpu, cpu_devices);
313 #endif
314
315 static void __init cpu_dev_register_generic(void)
316 {
317 #ifdef CONFIG_GENERIC_CPU_DEVICES
318         int i;
319
320         for_each_possible_cpu(i) {
321                 if (register_cpu(&per_cpu(cpu_devices, i), i))
322                         panic("Failed to register CPU device");
323         }
324 #endif
325 }
326
327 void __init cpu_dev_init(void)
328 {
329         if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
330                 panic("Failed to register CPU subsystem");
331
332         cpu_dev_register_generic();
333
334 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
335         sched_create_sysfs_power_savings_entries(cpu_subsys.dev_root);
336 #endif
337 }