2 * drivers/base/cpu.c - basic CPU class support
5 #include <linux/sysdev.h>
6 #include <linux/module.h>
7 #include <linux/init.h>
9 #include <linux/topology.h>
10 #include <linux/device.h>
14 struct sysdev_class cpu_sysdev_class
= {
17 EXPORT_SYMBOL(cpu_sysdev_class
);
19 static struct sys_device
*cpu_sys_devices
[NR_CPUS
];
21 #ifdef CONFIG_HOTPLUG_CPU
22 int __attribute__((weak
)) smp_prepare_cpu (int cpu
)
27 static ssize_t
show_online(struct sys_device
*dev
, char *buf
)
29 struct cpu
*cpu
= container_of(dev
, struct cpu
, sysdev
);
31 return sprintf(buf
, "%u\n", !!cpu_online(cpu
->sysdev
.id
));
34 static ssize_t
store_online(struct sys_device
*dev
, const char *buf
,
37 struct cpu
*cpu
= container_of(dev
, struct cpu
, sysdev
);
42 ret
= cpu_down(cpu
->sysdev
.id
);
44 kobject_uevent(&dev
->kobj
, KOBJ_OFFLINE
);
47 ret
= smp_prepare_cpu(cpu
->sysdev
.id
);
49 ret
= cpu_up(cpu
->sysdev
.id
);
51 kobject_uevent(&dev
->kobj
, KOBJ_ONLINE
);
61 static SYSDEV_ATTR(online
, 0600, show_online
, store_online
);
63 static void __devinit
register_cpu_control(struct cpu
*cpu
)
65 sysdev_create_file(&cpu
->sysdev
, &attr_online
);
67 void unregister_cpu(struct cpu
*cpu
, struct node
*root
)
69 int logical_cpu
= cpu
->sysdev
.id
;
72 sysfs_remove_link(&root
->sysdev
.kobj
,
73 kobject_name(&cpu
->sysdev
.kobj
));
74 sysdev_remove_file(&cpu
->sysdev
, &attr_online
);
76 sysdev_unregister(&cpu
->sysdev
);
77 cpu_sys_devices
[logical_cpu
] = NULL
;
80 #else /* ... !CONFIG_HOTPLUG_CPU */
81 static inline void register_cpu_control(struct cpu
*cpu
)
84 #endif /* CONFIG_HOTPLUG_CPU */
87 #include <linux/kexec.h>
89 static ssize_t
show_crash_notes(struct sys_device
*dev
, char *buf
)
91 struct cpu
*cpu
= container_of(dev
, struct cpu
, sysdev
);
93 unsigned long long addr
;
96 cpunum
= cpu
->sysdev
.id
;
99 * Might be reading other cpu's data based on which cpu read thread
100 * has been scheduled. But cpu data (memory) is allocated once during
101 * boot up and this data does not change there after. Hence this
102 * operation should be safe. No locking required.
104 addr
= __pa(per_cpu_ptr(crash_notes
, cpunum
));
105 rc
= sprintf(buf
, "%Lx\n", addr
);
108 static SYSDEV_ATTR(crash_notes
, 0400, show_crash_notes
, NULL
);
112 * register_cpu - Setup a driverfs device for a CPU.
113 * @cpu - Callers can set the cpu->no_control field to 1, to indicate not to
114 * generate a control file in sysfs for this CPU.
115 * @num - CPU number to use when creating the device.
117 * Initialize and register the CPU device.
119 int __devinit
register_cpu(struct cpu
*cpu
, int num
, struct node
*root
)
123 cpu
->node_id
= cpu_to_node(num
);
124 cpu
->sysdev
.id
= num
;
125 cpu
->sysdev
.cls
= &cpu_sysdev_class
;
127 error
= sysdev_register(&cpu
->sysdev
);
129 error
= sysfs_create_link(&root
->sysdev
.kobj
,
131 kobject_name(&cpu
->sysdev
.kobj
));
132 if (!error
&& !cpu
->no_control
)
133 register_cpu_control(cpu
);
135 cpu_sys_devices
[num
] = &cpu
->sysdev
;
139 error
= sysdev_create_file(&cpu
->sysdev
, &attr_crash_notes
);
144 struct sys_device
*get_cpu_sysdev(int cpu
)
147 return cpu_sys_devices
[cpu
];
151 EXPORT_SYMBOL_GPL(get_cpu_sysdev
);
153 int __init
cpu_dev_init(void)
155 return sysdev_class_register(&cpu_sysdev_class
);