Commit | Line | Data |
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1da177e4 | 1 | /* ----------------------------------------------------------------------- * |
2347d933 PA |
2 | * |
3 | * Copyright 2000-2008 H. Peter Anvin - All Rights Reserved | |
1da177e4 LT |
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 | * | |
2347d933 PA |
20 | * The lower 32 bits of the file position is used as the incoming %eax, |
21 | * and the upper 32 bits of the file position as the incoming %ecx, | |
22 | * the latter intended for "counting" eax levels like eax=4. | |
23 | * | |
1da177e4 LT |
24 | * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on |
25 | * an SMP box will direct the access to CPU %d. | |
26 | */ | |
27 | ||
28 | #include <linux/module.h> | |
1da177e4 LT |
29 | |
30 | #include <linux/types.h> | |
31 | #include <linux/errno.h> | |
32 | #include <linux/fcntl.h> | |
33 | #include <linux/init.h> | |
34 | #include <linux/poll.h> | |
35 | #include <linux/smp.h> | |
5119e92e | 36 | #include <linux/smp_lock.h> |
1da177e4 LT |
37 | #include <linux/major.h> |
38 | #include <linux/fs.h> | |
1da177e4 LT |
39 | #include <linux/device.h> |
40 | #include <linux/cpu.h> | |
41 | #include <linux/notifier.h> | |
f634fa94 | 42 | #include <linux/uaccess.h> |
1da177e4 LT |
43 | |
44 | #include <asm/processor.h> | |
45 | #include <asm/msr.h> | |
1da177e4 LT |
46 | #include <asm/system.h> |
47 | ||
8874b414 | 48 | static struct class *cpuid_class; |
1da177e4 | 49 | |
2347d933 PA |
50 | struct cpuid_regs { |
51 | u32 eax, ebx, ecx, edx; | |
1da177e4 LT |
52 | }; |
53 | ||
54 | static void cpuid_smp_cpuid(void *cmd_block) | |
55 | { | |
2347d933 | 56 | struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block; |
1da177e4 | 57 | |
2347d933 PA |
58 | cpuid_count(cmd->eax, cmd->ecx, |
59 | &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx); | |
1da177e4 LT |
60 | } |
61 | ||
1da177e4 LT |
62 | static loff_t cpuid_seek(struct file *file, loff_t offset, int orig) |
63 | { | |
64 | loff_t ret; | |
2b06ac86 | 65 | struct inode *inode = file->f_mapping->host; |
1da177e4 | 66 | |
2b06ac86 | 67 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
68 | switch (orig) { |
69 | case 0: | |
70 | file->f_pos = offset; | |
71 | ret = file->f_pos; | |
72 | break; | |
73 | case 1: | |
74 | file->f_pos += offset; | |
75 | ret = file->f_pos; | |
76 | break; | |
77 | default: | |
78 | ret = -EINVAL; | |
79 | } | |
2b06ac86 | 80 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
81 | return ret; |
82 | } | |
83 | ||
84 | static ssize_t cpuid_read(struct file *file, char __user *buf, | |
f634fa94 | 85 | size_t count, loff_t *ppos) |
1da177e4 LT |
86 | { |
87 | char __user *tmp = buf; | |
2347d933 | 88 | struct cpuid_regs cmd; |
aab4c5a5 | 89 | int cpu = iminor(file->f_path.dentry->d_inode); |
2347d933 | 90 | u64 pos = *ppos; |
9ea2b82e PA |
91 | ssize_t bytes = 0; |
92 | int err = 0; | |
1da177e4 LT |
93 | |
94 | if (count % 16) | |
95 | return -EINVAL; /* Invalid chunk size */ | |
96 | ||
6b7f430e | 97 | for (; count; count -= 16) { |
2347d933 PA |
98 | cmd.eax = pos; |
99 | cmd.ecx = pos >> 32; | |
4b46ca70 PA |
100 | err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1); |
101 | if (err) | |
9ea2b82e PA |
102 | break; |
103 | if (copy_to_user(tmp, &cmd, 16)) { | |
104 | err = -EFAULT; | |
105 | break; | |
106 | } | |
1da177e4 | 107 | tmp += 16; |
9ea2b82e | 108 | bytes += 16; |
2347d933 | 109 | *ppos = ++pos; |
1da177e4 LT |
110 | } |
111 | ||
9ea2b82e | 112 | return bytes ? bytes : err; |
1da177e4 LT |
113 | } |
114 | ||
115 | static int cpuid_open(struct inode *inode, struct file *file) | |
116 | { | |
5119e92e JC |
117 | unsigned int cpu; |
118 | struct cpuinfo_x86 *c; | |
119 | int ret = 0; | |
f634fa94 | 120 | |
5119e92e JC |
121 | lock_kernel(); |
122 | ||
123 | cpu = iminor(file->f_path.dentry->d_inode); | |
9628937d | 124 | if (cpu >= nr_cpu_ids || !cpu_online(cpu)) { |
5119e92e JC |
125 | ret = -ENXIO; /* No such CPU */ |
126 | goto out; | |
127 | } | |
128 | c = &cpu_data(cpu); | |
1da177e4 | 129 | if (c->cpuid_level < 0) |
5119e92e JC |
130 | ret = -EIO; /* CPUID not supported */ |
131 | out: | |
132 | unlock_kernel(); | |
133 | return ret; | |
1da177e4 LT |
134 | } |
135 | ||
136 | /* | |
137 | * File operations we support | |
138 | */ | |
5dfe4c96 | 139 | static const struct file_operations cpuid_fops = { |
1da177e4 LT |
140 | .owner = THIS_MODULE, |
141 | .llseek = cpuid_seek, | |
142 | .read = cpuid_read, | |
143 | .open = cpuid_open, | |
144 | }; | |
145 | ||
1f503e77 | 146 | static __cpuinit int cpuid_device_create(int cpu) |
1da177e4 | 147 | { |
07accdc1 | 148 | struct device *dev; |
1da177e4 | 149 | |
a9b12619 GKH |
150 | dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL, |
151 | "cpu%d", cpu); | |
1f503e77 AM |
152 | return IS_ERR(dev) ? PTR_ERR(dev) : 0; |
153 | } | |
154 | ||
155 | static void cpuid_device_destroy(int cpu) | |
156 | { | |
157 | device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu)); | |
1da177e4 LT |
158 | } |
159 | ||
1e32b073 SS |
160 | static int __cpuinit cpuid_class_cpu_callback(struct notifier_block *nfb, |
161 | unsigned long action, | |
162 | void *hcpu) | |
1da177e4 LT |
163 | { |
164 | unsigned int cpu = (unsigned long)hcpu; | |
1f503e77 | 165 | int err = 0; |
1da177e4 LT |
166 | |
167 | switch (action) { | |
1f503e77 | 168 | case CPU_UP_PREPARE: |
1f503e77 | 169 | err = cpuid_device_create(cpu); |
1da177e4 | 170 | break; |
1f503e77 | 171 | case CPU_UP_CANCELED: |
b844eba2 | 172 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 173 | case CPU_DEAD: |
1f503e77 | 174 | cpuid_device_destroy(cpu); |
1da177e4 LT |
175 | break; |
176 | } | |
1f503e77 | 177 | return err ? NOTIFY_BAD : NOTIFY_OK; |
1da177e4 LT |
178 | } |
179 | ||
c72258c7 | 180 | static struct notifier_block __refdata cpuid_class_cpu_notifier = |
1da177e4 LT |
181 | { |
182 | .notifier_call = cpuid_class_cpu_callback, | |
183 | }; | |
184 | ||
07e9bb8e KS |
185 | static char *cpuid_nodename(struct device *dev) |
186 | { | |
187 | return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt)); | |
188 | } | |
189 | ||
1da177e4 LT |
190 | static int __init cpuid_init(void) |
191 | { | |
192 | int i, err = 0; | |
193 | i = 0; | |
194 | ||
195 | if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) { | |
196 | printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n", | |
197 | CPUID_MAJOR); | |
198 | err = -EBUSY; | |
199 | goto out; | |
200 | } | |
8874b414 | 201 | cpuid_class = class_create(THIS_MODULE, "cpuid"); |
1da177e4 LT |
202 | if (IS_ERR(cpuid_class)) { |
203 | err = PTR_ERR(cpuid_class); | |
204 | goto out_chrdev; | |
205 | } | |
07e9bb8e | 206 | cpuid_class->nodename = cpuid_nodename; |
1da177e4 | 207 | for_each_online_cpu(i) { |
07accdc1 | 208 | err = cpuid_device_create(i); |
2347d933 | 209 | if (err != 0) |
1da177e4 LT |
210 | goto out_class; |
211 | } | |
b6a7c79a | 212 | register_hotcpu_notifier(&cpuid_class_cpu_notifier); |
1da177e4 LT |
213 | |
214 | err = 0; | |
215 | goto out; | |
216 | ||
217 | out_class: | |
218 | i = 0; | |
219 | for_each_online_cpu(i) { | |
1f503e77 | 220 | cpuid_device_destroy(i); |
1da177e4 | 221 | } |
8874b414 | 222 | class_destroy(cpuid_class); |
1da177e4 | 223 | out_chrdev: |
2347d933 | 224 | unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); |
1da177e4 LT |
225 | out: |
226 | return err; | |
227 | } | |
228 | ||
229 | static void __exit cpuid_exit(void) | |
230 | { | |
231 | int cpu = 0; | |
232 | ||
233 | for_each_online_cpu(cpu) | |
1f503e77 | 234 | cpuid_device_destroy(cpu); |
8874b414 | 235 | class_destroy(cpuid_class); |
1da177e4 | 236 | unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); |
b6a7c79a | 237 | unregister_hotcpu_notifier(&cpuid_class_cpu_notifier); |
1da177e4 LT |
238 | } |
239 | ||
240 | module_init(cpuid_init); | |
241 | module_exit(cpuid_exit); | |
242 | ||
243 | MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>"); | |
244 | MODULE_DESCRIPTION("x86 generic CPUID driver"); | |
245 | MODULE_LICENSE("GPL"); |