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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 | /* | |
1da177e4 LT |
14 | * x86 CPUID access device |
15 | * | |
16 | * This device is accessed by lseek() to the appropriate CPUID level | |
17 | * and then read in chunks of 16 bytes. A larger size means multiple | |
18 | * reads of consecutive levels. | |
19 | * | |
20 | * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on | |
21 | * an SMP box will direct the access to CPU %d. | |
22 | */ | |
23 | ||
24 | #include <linux/module.h> | |
1da177e4 LT |
25 | |
26 | #include <linux/types.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/fcntl.h> | |
29 | #include <linux/init.h> | |
30 | #include <linux/poll.h> | |
31 | #include <linux/smp.h> | |
32 | #include <linux/major.h> | |
33 | #include <linux/fs.h> | |
34 | #include <linux/smp_lock.h> | |
1da177e4 LT |
35 | #include <linux/device.h> |
36 | #include <linux/cpu.h> | |
37 | #include <linux/notifier.h> | |
38 | ||
39 | #include <asm/processor.h> | |
40 | #include <asm/msr.h> | |
41 | #include <asm/uaccess.h> | |
42 | #include <asm/system.h> | |
43 | ||
8874b414 | 44 | static struct class *cpuid_class; |
1da177e4 | 45 | |
1da177e4 | 46 | struct cpuid_command { |
1da177e4 LT |
47 | u32 reg; |
48 | u32 *data; | |
49 | }; | |
50 | ||
51 | static void cpuid_smp_cpuid(void *cmd_block) | |
52 | { | |
53 | struct cpuid_command *cmd = (struct cpuid_command *)cmd_block; | |
54 | ||
ad4e680f | 55 | cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2], |
1da177e4 LT |
56 | &cmd->data[3]); |
57 | } | |
58 | ||
59 | static inline void do_cpuid(int cpu, u32 reg, u32 * data) | |
60 | { | |
61 | struct cpuid_command cmd; | |
62 | ||
4a40cb1e AK |
63 | cmd.reg = reg; |
64 | cmd.data = data; | |
1da177e4 | 65 | |
4a40cb1e | 66 | smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1); |
1da177e4 LT |
67 | } |
68 | ||
1da177e4 LT |
69 | static loff_t cpuid_seek(struct file *file, loff_t offset, int orig) |
70 | { | |
71 | loff_t ret; | |
72 | ||
73 | lock_kernel(); | |
74 | ||
75 | switch (orig) { | |
76 | case 0: | |
77 | file->f_pos = offset; | |
78 | ret = file->f_pos; | |
79 | break; | |
80 | case 1: | |
81 | file->f_pos += offset; | |
82 | ret = file->f_pos; | |
83 | break; | |
84 | default: | |
85 | ret = -EINVAL; | |
86 | } | |
87 | ||
88 | unlock_kernel(); | |
89 | return ret; | |
90 | } | |
91 | ||
92 | static ssize_t cpuid_read(struct file *file, char __user *buf, | |
93 | size_t count, loff_t * ppos) | |
94 | { | |
95 | char __user *tmp = buf; | |
96 | u32 data[4]; | |
1da177e4 | 97 | u32 reg = *ppos; |
aab4c5a5 | 98 | int cpu = iminor(file->f_path.dentry->d_inode); |
1da177e4 LT |
99 | |
100 | if (count % 16) | |
101 | return -EINVAL; /* Invalid chunk size */ | |
102 | ||
6b7f430e | 103 | for (; count; count -= 16) { |
1da177e4 LT |
104 | do_cpuid(cpu, reg, data); |
105 | if (copy_to_user(tmp, &data, 16)) | |
106 | return -EFAULT; | |
107 | tmp += 16; | |
108 | *ppos = reg++; | |
109 | } | |
110 | ||
111 | return tmp - buf; | |
112 | } | |
113 | ||
114 | static int cpuid_open(struct inode *inode, struct file *file) | |
115 | { | |
aab4c5a5 | 116 | unsigned int cpu = iminor(file->f_path.dentry->d_inode); |
92cb7612 | 117 | struct cpuinfo_x86 *c = &cpu_data(cpu); |
1da177e4 LT |
118 | |
119 | if (cpu >= NR_CPUS || !cpu_online(cpu)) | |
120 | return -ENXIO; /* No such CPU */ | |
121 | if (c->cpuid_level < 0) | |
122 | return -EIO; /* CPUID not supported */ | |
123 | ||
124 | return 0; | |
125 | } | |
126 | ||
127 | /* | |
128 | * File operations we support | |
129 | */ | |
5dfe4c96 | 130 | static const struct file_operations cpuid_fops = { |
1da177e4 LT |
131 | .owner = THIS_MODULE, |
132 | .llseek = cpuid_seek, | |
133 | .read = cpuid_read, | |
134 | .open = cpuid_open, | |
135 | }; | |
136 | ||
1f503e77 | 137 | static __cpuinit int cpuid_device_create(int cpu) |
1da177e4 | 138 | { |
07accdc1 | 139 | struct device *dev; |
1da177e4 | 140 | |
1f503e77 AM |
141 | dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), |
142 | "cpu%d", cpu); | |
143 | return IS_ERR(dev) ? PTR_ERR(dev) : 0; | |
144 | } | |
145 | ||
146 | static void cpuid_device_destroy(int cpu) | |
147 | { | |
148 | device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu)); | |
1da177e4 LT |
149 | } |
150 | ||
1e32b073 SS |
151 | static int __cpuinit cpuid_class_cpu_callback(struct notifier_block *nfb, |
152 | unsigned long action, | |
153 | void *hcpu) | |
1da177e4 LT |
154 | { |
155 | unsigned int cpu = (unsigned long)hcpu; | |
1f503e77 | 156 | int err = 0; |
1da177e4 LT |
157 | |
158 | switch (action) { | |
1f503e77 AM |
159 | case CPU_UP_PREPARE: |
160 | case CPU_UP_PREPARE_FROZEN: | |
161 | err = cpuid_device_create(cpu); | |
1da177e4 | 162 | break; |
1f503e77 AM |
163 | case CPU_UP_CANCELED: |
164 | case CPU_UP_CANCELED_FROZEN: | |
1da177e4 | 165 | case CPU_DEAD: |
8bb78442 | 166 | case CPU_DEAD_FROZEN: |
1f503e77 | 167 | cpuid_device_destroy(cpu); |
1da177e4 LT |
168 | break; |
169 | } | |
1f503e77 | 170 | return err ? NOTIFY_BAD : NOTIFY_OK; |
1da177e4 LT |
171 | } |
172 | ||
74b85f37 | 173 | static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier = |
1da177e4 LT |
174 | { |
175 | .notifier_call = cpuid_class_cpu_callback, | |
176 | }; | |
177 | ||
178 | static int __init cpuid_init(void) | |
179 | { | |
180 | int i, err = 0; | |
181 | i = 0; | |
182 | ||
183 | if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) { | |
184 | printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n", | |
185 | CPUID_MAJOR); | |
186 | err = -EBUSY; | |
187 | goto out; | |
188 | } | |
8874b414 | 189 | cpuid_class = class_create(THIS_MODULE, "cpuid"); |
1da177e4 LT |
190 | if (IS_ERR(cpuid_class)) { |
191 | err = PTR_ERR(cpuid_class); | |
192 | goto out_chrdev; | |
193 | } | |
194 | for_each_online_cpu(i) { | |
07accdc1 | 195 | err = cpuid_device_create(i); |
1da177e4 LT |
196 | if (err != 0) |
197 | goto out_class; | |
198 | } | |
b6a7c79a | 199 | register_hotcpu_notifier(&cpuid_class_cpu_notifier); |
1da177e4 LT |
200 | |
201 | err = 0; | |
202 | goto out; | |
203 | ||
204 | out_class: | |
205 | i = 0; | |
206 | for_each_online_cpu(i) { | |
1f503e77 | 207 | cpuid_device_destroy(i); |
1da177e4 | 208 | } |
8874b414 | 209 | class_destroy(cpuid_class); |
1da177e4 LT |
210 | out_chrdev: |
211 | unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); | |
212 | out: | |
213 | return err; | |
214 | } | |
215 | ||
216 | static void __exit cpuid_exit(void) | |
217 | { | |
218 | int cpu = 0; | |
219 | ||
220 | for_each_online_cpu(cpu) | |
1f503e77 | 221 | cpuid_device_destroy(cpu); |
8874b414 | 222 | class_destroy(cpuid_class); |
1da177e4 | 223 | unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); |
b6a7c79a | 224 | unregister_hotcpu_notifier(&cpuid_class_cpu_notifier); |
1da177e4 LT |
225 | } |
226 | ||
227 | module_init(cpuid_init); | |
228 | module_exit(cpuid_exit); | |
229 | ||
230 | MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>"); | |
231 | MODULE_DESCRIPTION("x86 generic CPUID driver"); | |
232 | MODULE_LICENSE("GPL"); |