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1da177e4 LT |
1 | /* ----------------------------------------------------------------------- * |
2 | * | |
3 | * Copyright 2000 H. Peter Anvin - All Rights Reserved | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139, | |
8 | * USA; either version 2 of the License, or (at your option) any later | |
9 | * version; incorporated herein by reference. | |
10 | * | |
11 | * ----------------------------------------------------------------------- */ | |
12 | ||
13 | /* | |
14 | * cpuid.c | |
15 | * | |
16 | * x86 CPUID access device | |
17 | * | |
18 | * This device is accessed by lseek() to the appropriate CPUID level | |
19 | * and then read in chunks of 16 bytes. A larger size means multiple | |
20 | * reads of consecutive levels. | |
21 | * | |
22 | * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on | |
23 | * an SMP box will direct the access to CPU %d. | |
24 | */ | |
25 | ||
26 | #include <linux/module.h> | |
27 | #include <linux/config.h> | |
28 | ||
29 | #include <linux/types.h> | |
30 | #include <linux/errno.h> | |
31 | #include <linux/fcntl.h> | |
32 | #include <linux/init.h> | |
33 | #include <linux/poll.h> | |
34 | #include <linux/smp.h> | |
35 | #include <linux/major.h> | |
36 | #include <linux/fs.h> | |
37 | #include <linux/smp_lock.h> | |
38 | #include <linux/fs.h> | |
39 | #include <linux/device.h> | |
40 | #include <linux/cpu.h> | |
41 | #include <linux/notifier.h> | |
42 | ||
43 | #include <asm/processor.h> | |
44 | #include <asm/msr.h> | |
45 | #include <asm/uaccess.h> | |
46 | #include <asm/system.h> | |
47 | ||
48 | static struct class_simple *cpuid_class; | |
49 | ||
50 | #ifdef CONFIG_SMP | |
51 | ||
52 | struct cpuid_command { | |
53 | int cpu; | |
54 | u32 reg; | |
55 | u32 *data; | |
56 | }; | |
57 | ||
58 | static void cpuid_smp_cpuid(void *cmd_block) | |
59 | { | |
60 | struct cpuid_command *cmd = (struct cpuid_command *)cmd_block; | |
61 | ||
62 | if (cmd->cpu == smp_processor_id()) | |
63 | cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2], | |
64 | &cmd->data[3]); | |
65 | } | |
66 | ||
67 | static inline void do_cpuid(int cpu, u32 reg, u32 * data) | |
68 | { | |
69 | struct cpuid_command cmd; | |
70 | ||
71 | preempt_disable(); | |
72 | if (cpu == smp_processor_id()) { | |
73 | cpuid(reg, &data[0], &data[1], &data[2], &data[3]); | |
74 | } else { | |
75 | cmd.cpu = cpu; | |
76 | cmd.reg = reg; | |
77 | cmd.data = data; | |
78 | ||
79 | smp_call_function(cpuid_smp_cpuid, &cmd, 1, 1); | |
80 | } | |
81 | preempt_enable(); | |
82 | } | |
83 | #else /* ! CONFIG_SMP */ | |
84 | ||
85 | static inline void do_cpuid(int cpu, u32 reg, u32 * data) | |
86 | { | |
87 | cpuid(reg, &data[0], &data[1], &data[2], &data[3]); | |
88 | } | |
89 | ||
90 | #endif /* ! CONFIG_SMP */ | |
91 | ||
92 | static loff_t cpuid_seek(struct file *file, loff_t offset, int orig) | |
93 | { | |
94 | loff_t ret; | |
95 | ||
96 | lock_kernel(); | |
97 | ||
98 | switch (orig) { | |
99 | case 0: | |
100 | file->f_pos = offset; | |
101 | ret = file->f_pos; | |
102 | break; | |
103 | case 1: | |
104 | file->f_pos += offset; | |
105 | ret = file->f_pos; | |
106 | break; | |
107 | default: | |
108 | ret = -EINVAL; | |
109 | } | |
110 | ||
111 | unlock_kernel(); | |
112 | return ret; | |
113 | } | |
114 | ||
115 | static ssize_t cpuid_read(struct file *file, char __user *buf, | |
116 | size_t count, loff_t * ppos) | |
117 | { | |
118 | char __user *tmp = buf; | |
119 | u32 data[4]; | |
120 | size_t rv; | |
121 | u32 reg = *ppos; | |
122 | int cpu = iminor(file->f_dentry->d_inode); | |
123 | ||
124 | if (count % 16) | |
125 | return -EINVAL; /* Invalid chunk size */ | |
126 | ||
127 | for (rv = 0; count; count -= 16) { | |
128 | do_cpuid(cpu, reg, data); | |
129 | if (copy_to_user(tmp, &data, 16)) | |
130 | return -EFAULT; | |
131 | tmp += 16; | |
132 | *ppos = reg++; | |
133 | } | |
134 | ||
135 | return tmp - buf; | |
136 | } | |
137 | ||
138 | static int cpuid_open(struct inode *inode, struct file *file) | |
139 | { | |
140 | unsigned int cpu = iminor(file->f_dentry->d_inode); | |
141 | struct cpuinfo_x86 *c = &(cpu_data)[cpu]; | |
142 | ||
143 | if (cpu >= NR_CPUS || !cpu_online(cpu)) | |
144 | return -ENXIO; /* No such CPU */ | |
145 | if (c->cpuid_level < 0) | |
146 | return -EIO; /* CPUID not supported */ | |
147 | ||
148 | return 0; | |
149 | } | |
150 | ||
151 | /* | |
152 | * File operations we support | |
153 | */ | |
154 | static struct file_operations cpuid_fops = { | |
155 | .owner = THIS_MODULE, | |
156 | .llseek = cpuid_seek, | |
157 | .read = cpuid_read, | |
158 | .open = cpuid_open, | |
159 | }; | |
160 | ||
161 | static int cpuid_class_simple_device_add(int i) | |
162 | { | |
163 | int err = 0; | |
164 | struct class_device *class_err; | |
165 | ||
166 | class_err = class_simple_device_add(cpuid_class, MKDEV(CPUID_MAJOR, i), NULL, "cpu%d",i); | |
167 | if (IS_ERR(class_err)) | |
168 | err = PTR_ERR(class_err); | |
169 | return err; | |
170 | } | |
171 | ||
172 | static int __devinit cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
173 | { | |
174 | unsigned int cpu = (unsigned long)hcpu; | |
175 | ||
176 | switch (action) { | |
177 | case CPU_ONLINE: | |
178 | cpuid_class_simple_device_add(cpu); | |
179 | break; | |
180 | case CPU_DEAD: | |
181 | class_simple_device_remove(MKDEV(CPUID_MAJOR, cpu)); | |
182 | break; | |
183 | } | |
184 | return NOTIFY_OK; | |
185 | } | |
186 | ||
187 | static struct notifier_block cpuid_class_cpu_notifier = | |
188 | { | |
189 | .notifier_call = cpuid_class_cpu_callback, | |
190 | }; | |
191 | ||
192 | static int __init cpuid_init(void) | |
193 | { | |
194 | int i, err = 0; | |
195 | i = 0; | |
196 | ||
197 | if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) { | |
198 | printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n", | |
199 | CPUID_MAJOR); | |
200 | err = -EBUSY; | |
201 | goto out; | |
202 | } | |
203 | cpuid_class = class_simple_create(THIS_MODULE, "cpuid"); | |
204 | if (IS_ERR(cpuid_class)) { | |
205 | err = PTR_ERR(cpuid_class); | |
206 | goto out_chrdev; | |
207 | } | |
208 | for_each_online_cpu(i) { | |
209 | err = cpuid_class_simple_device_add(i); | |
210 | if (err != 0) | |
211 | goto out_class; | |
212 | } | |
213 | register_cpu_notifier(&cpuid_class_cpu_notifier); | |
214 | ||
215 | err = 0; | |
216 | goto out; | |
217 | ||
218 | out_class: | |
219 | i = 0; | |
220 | for_each_online_cpu(i) { | |
221 | class_simple_device_remove(MKDEV(CPUID_MAJOR, i)); | |
222 | } | |
223 | class_simple_destroy(cpuid_class); | |
224 | out_chrdev: | |
225 | unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); | |
226 | out: | |
227 | return err; | |
228 | } | |
229 | ||
230 | static void __exit cpuid_exit(void) | |
231 | { | |
232 | int cpu = 0; | |
233 | ||
234 | for_each_online_cpu(cpu) | |
235 | class_simple_device_remove(MKDEV(CPUID_MAJOR, cpu)); | |
236 | class_simple_destroy(cpuid_class); | |
237 | unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); | |
238 | unregister_cpu_notifier(&cpuid_class_cpu_notifier); | |
239 | } | |
240 | ||
241 | module_init(cpuid_init); | |
242 | module_exit(cpuid_exit); | |
243 | ||
244 | MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>"); | |
245 | MODULE_DESCRIPTION("x86 generic CPUID driver"); | |
246 | MODULE_LICENSE("GPL"); |