2 * CPU subsystem support
5 #include <linux/module.h>
6 #include <linux/init.h>
7 #include <linux/sched.h>
9 #include <linux/topology.h>
10 #include <linux/device.h>
11 #include <linux/node.h>
12 #include <linux/gfp.h>
16 struct bus_type cpu_subsys
= {
20 EXPORT_SYMBOL_GPL(cpu_subsys
);
22 static DEFINE_PER_CPU(struct device
*, cpu_sys_devices
);
24 #ifdef CONFIG_HOTPLUG_CPU
25 static ssize_t
show_online(struct device
*dev
,
26 struct device_attribute
*attr
,
29 struct cpu
*cpu
= container_of(dev
, struct cpu
, dev
);
31 return sprintf(buf
, "%u\n", !!cpu_online(cpu
->dev
.id
));
34 static ssize_t __ref
store_online(struct device
*dev
,
35 struct device_attribute
*attr
,
36 const char *buf
, size_t count
)
38 struct cpu
*cpu
= container_of(dev
, struct cpu
, dev
);
41 cpu_hotplug_driver_lock();
44 ret
= cpu_down(cpu
->dev
.id
);
46 kobject_uevent(&dev
->kobj
, KOBJ_OFFLINE
);
49 ret
= cpu_up(cpu
->dev
.id
);
51 kobject_uevent(&dev
->kobj
, KOBJ_ONLINE
);
56 cpu_hotplug_driver_unlock();
62 static DEVICE_ATTR(online
, 0644, show_online
, store_online
);
64 static void __cpuinit
register_cpu_control(struct cpu
*cpu
)
66 device_create_file(&cpu
->dev
, &dev_attr_online
);
68 void unregister_cpu(struct cpu
*cpu
)
70 int logical_cpu
= cpu
->dev
.id
;
72 unregister_cpu_under_node(logical_cpu
, cpu_to_node(logical_cpu
));
74 device_remove_file(&cpu
->dev
, &dev_attr_online
);
76 device_unregister(&cpu
->dev
);
77 per_cpu(cpu_sys_devices
, logical_cpu
) = NULL
;
81 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
82 static ssize_t
cpu_probe_store(struct device
*dev
,
83 struct device_attribute
*attr
,
87 return arch_cpu_probe(buf
, count
);
90 static ssize_t
cpu_release_store(struct device
*dev
,
91 struct device_attribute
*attr
,
95 return arch_cpu_release(buf
, count
);
98 static DEVICE_ATTR(probe
, S_IWUSR
, NULL
, cpu_probe_store
);
99 static DEVICE_ATTR(release
, S_IWUSR
, NULL
, cpu_release_store
);
100 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
102 #else /* ... !CONFIG_HOTPLUG_CPU */
103 static inline void register_cpu_control(struct cpu
*cpu
)
106 #endif /* CONFIG_HOTPLUG_CPU */
109 #include <linux/kexec.h>
111 static ssize_t
show_crash_notes(struct device
*dev
, struct device_attribute
*attr
,
114 struct cpu
*cpu
= container_of(dev
, struct cpu
, dev
);
116 unsigned long long addr
;
119 cpunum
= cpu
->dev
.id
;
122 * Might be reading other cpu's data based on which cpu read thread
123 * has been scheduled. But cpu data (memory) is allocated once during
124 * boot up and this data does not change there after. Hence this
125 * operation should be safe. No locking required.
127 addr
= per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes
, cpunum
));
128 rc
= sprintf(buf
, "%Lx\n", addr
);
131 static DEVICE_ATTR(crash_notes
, 0400, show_crash_notes
, NULL
);
135 * Print cpu online, possible, present, and system maps
139 struct device_attribute attr
;
140 const struct cpumask
*const * const map
;
143 static ssize_t
show_cpus_attr(struct device
*dev
,
144 struct device_attribute
*attr
,
147 struct cpu_attr
*ca
= container_of(attr
, struct cpu_attr
, attr
);
148 int n
= cpulist_scnprintf(buf
, PAGE_SIZE
-2, *(ca
->map
));
155 #define _CPU_ATTR(name, map) \
156 { __ATTR(name, 0444, show_cpus_attr, NULL), map }
158 /* Keep in sync with cpu_subsys_attrs */
159 static struct cpu_attr cpu_attrs
[] = {
160 _CPU_ATTR(online
, &cpu_online_mask
),
161 _CPU_ATTR(possible
, &cpu_possible_mask
),
162 _CPU_ATTR(present
, &cpu_present_mask
),
166 * Print values for NR_CPUS and offlined cpus
168 static ssize_t
print_cpus_kernel_max(struct device
*dev
,
169 struct device_attribute
*attr
, char *buf
)
171 int n
= snprintf(buf
, PAGE_SIZE
-2, "%d\n", NR_CPUS
- 1);
174 static DEVICE_ATTR(kernel_max
, 0444, print_cpus_kernel_max
, NULL
);
176 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
177 unsigned int total_cpus
;
179 static ssize_t
print_cpus_offline(struct device
*dev
,
180 struct device_attribute
*attr
, char *buf
)
182 int n
= 0, len
= PAGE_SIZE
-2;
183 cpumask_var_t offline
;
185 /* display offline cpus < nr_cpu_ids */
186 if (!alloc_cpumask_var(&offline
, GFP_KERNEL
))
188 cpumask_andnot(offline
, cpu_possible_mask
, cpu_online_mask
);
189 n
= cpulist_scnprintf(buf
, len
, offline
);
190 free_cpumask_var(offline
);
192 /* display offline cpus >= nr_cpu_ids */
193 if (total_cpus
&& nr_cpu_ids
< total_cpus
) {
197 if (nr_cpu_ids
== total_cpus
-1)
198 n
+= snprintf(&buf
[n
], len
- n
, "%d", nr_cpu_ids
);
200 n
+= snprintf(&buf
[n
], len
- n
, "%d-%d",
201 nr_cpu_ids
, total_cpus
-1);
204 n
+= snprintf(&buf
[n
], len
- n
, "\n");
207 static DEVICE_ATTR(offline
, 0444, print_cpus_offline
, NULL
);
210 * register_cpu - Setup a sysfs device for a CPU.
211 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
212 * sysfs for this CPU.
213 * @num - CPU number to use when creating the device.
215 * Initialize and register the CPU device.
217 int __cpuinit
register_cpu(struct cpu
*cpu
, int num
)
221 cpu
->node_id
= cpu_to_node(num
);
223 cpu
->dev
.bus
= &cpu_subsys
;
224 error
= device_register(&cpu
->dev
);
225 if (!error
&& cpu
->hotpluggable
)
226 register_cpu_control(cpu
);
228 per_cpu(cpu_sys_devices
, num
) = &cpu
->dev
;
230 register_cpu_under_node(num
, cpu_to_node(num
));
234 error
= device_create_file(&cpu
->dev
, &dev_attr_crash_notes
);
239 struct device
*get_cpu_device(unsigned cpu
)
241 if (cpu
< nr_cpu_ids
&& cpu_possible(cpu
))
242 return per_cpu(cpu_sys_devices
, cpu
);
246 EXPORT_SYMBOL_GPL(get_cpu_device
);
248 static struct attribute
*cpu_root_attrs
[] = {
249 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
250 &dev_attr_probe
.attr
,
251 &dev_attr_release
.attr
,
253 &cpu_attrs
[0].attr
.attr
,
254 &cpu_attrs
[1].attr
.attr
,
255 &cpu_attrs
[2].attr
.attr
,
256 &dev_attr_kernel_max
.attr
,
257 &dev_attr_offline
.attr
,
261 static struct attribute_group cpu_root_attr_group
= {
262 .attrs
= cpu_root_attrs
,
265 static const struct attribute_group
*cpu_root_attr_groups
[] = {
266 &cpu_root_attr_group
,
270 bool cpu_is_hotpluggable(unsigned cpu
)
272 struct device
*dev
= get_cpu_device(cpu
);
273 return dev
&& container_of(dev
, struct cpu
, dev
)->hotpluggable
;
275 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable
);
277 int __init
cpu_dev_init(void)
281 err
= subsys_system_register(&cpu_subsys
, cpu_root_attr_groups
);
285 #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
286 err
= sched_create_sysfs_power_savings_entries(cpu_subsys
.dev_root
);