This source file includes following definitions.
- cpuid_smp_cpuid
- cpuid_read
- cpuid_open
- cpuid_device_create
- cpuid_device_destroy
- cpuid_devnode
- cpuid_init
- cpuid_exit
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23 #include <linux/module.h>
24
25 #include <linux/types.h>
26 #include <linux/errno.h>
27 #include <linux/fcntl.h>
28 #include <linux/init.h>
29 #include <linux/poll.h>
30 #include <linux/smp.h>
31 #include <linux/major.h>
32 #include <linux/fs.h>
33 #include <linux/device.h>
34 #include <linux/cpu.h>
35 #include <linux/notifier.h>
36 #include <linux/uaccess.h>
37 #include <linux/gfp.h>
38 #include <linux/completion.h>
39
40 #include <asm/processor.h>
41 #include <asm/msr.h>
42
43 static struct class *cpuid_class;
44 static enum cpuhp_state cpuhp_cpuid_state;
45
46 struct cpuid_regs_done {
47 struct cpuid_regs regs;
48 struct completion done;
49 };
50
51 static void cpuid_smp_cpuid(void *cmd_block)
52 {
53 struct cpuid_regs_done *cmd = cmd_block;
54
55 cpuid_count(cmd->regs.eax, cmd->regs.ecx,
56 &cmd->regs.eax, &cmd->regs.ebx,
57 &cmd->regs.ecx, &cmd->regs.edx);
58
59 complete(&cmd->done);
60 }
61
62 static ssize_t cpuid_read(struct file *file, char __user *buf,
63 size_t count, loff_t *ppos)
64 {
65 char __user *tmp = buf;
66 struct cpuid_regs_done cmd;
67 int cpu = iminor(file_inode(file));
68 u64 pos = *ppos;
69 ssize_t bytes = 0;
70 int err = 0;
71
72 if (count % 16)
73 return -EINVAL;
74
75 init_completion(&cmd.done);
76 for (; count; count -= 16) {
77 call_single_data_t csd = {
78 .func = cpuid_smp_cpuid,
79 .info = &cmd,
80 };
81
82 cmd.regs.eax = pos;
83 cmd.regs.ecx = pos >> 32;
84
85 err = smp_call_function_single_async(cpu, &csd);
86 if (err)
87 break;
88 wait_for_completion(&cmd.done);
89 if (copy_to_user(tmp, &cmd.regs, 16)) {
90 err = -EFAULT;
91 break;
92 }
93 tmp += 16;
94 bytes += 16;
95 *ppos = ++pos;
96 reinit_completion(&cmd.done);
97 }
98
99 return bytes ? bytes : err;
100 }
101
102 static int cpuid_open(struct inode *inode, struct file *file)
103 {
104 unsigned int cpu;
105 struct cpuinfo_x86 *c;
106
107 cpu = iminor(file_inode(file));
108 if (cpu >= nr_cpu_ids || !cpu_online(cpu))
109 return -ENXIO;
110
111 c = &cpu_data(cpu);
112 if (c->cpuid_level < 0)
113 return -EIO;
114
115 return 0;
116 }
117
118
119
120
121 static const struct file_operations cpuid_fops = {
122 .owner = THIS_MODULE,
123 .llseek = no_seek_end_llseek,
124 .read = cpuid_read,
125 .open = cpuid_open,
126 };
127
128 static int cpuid_device_create(unsigned int cpu)
129 {
130 struct device *dev;
131
132 dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL,
133 "cpu%d", cpu);
134 return PTR_ERR_OR_ZERO(dev);
135 }
136
137 static int cpuid_device_destroy(unsigned int cpu)
138 {
139 device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
140 return 0;
141 }
142
143 static char *cpuid_devnode(struct device *dev, umode_t *mode)
144 {
145 return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
146 }
147
148 static int __init cpuid_init(void)
149 {
150 int err;
151
152 if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
153 "cpu/cpuid", &cpuid_fops)) {
154 printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
155 CPUID_MAJOR);
156 return -EBUSY;
157 }
158 cpuid_class = class_create(THIS_MODULE, "cpuid");
159 if (IS_ERR(cpuid_class)) {
160 err = PTR_ERR(cpuid_class);
161 goto out_chrdev;
162 }
163 cpuid_class->devnode = cpuid_devnode;
164
165 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/cpuid:online",
166 cpuid_device_create, cpuid_device_destroy);
167 if (err < 0)
168 goto out_class;
169
170 cpuhp_cpuid_state = err;
171 return 0;
172
173 out_class:
174 class_destroy(cpuid_class);
175 out_chrdev:
176 __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
177 return err;
178 }
179 module_init(cpuid_init);
180
181 static void __exit cpuid_exit(void)
182 {
183 cpuhp_remove_state(cpuhp_cpuid_state);
184 class_destroy(cpuid_class);
185 __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
186 }
187 module_exit(cpuid_exit);
188
189 MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
190 MODULE_DESCRIPTION("x86 generic CPUID driver");
191 MODULE_LICENSE("GPL");