Commit | Line | Data |
---|---|---|
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> |
5a0e3ad6 | 43 | #include <linux/gfp.h> |
1da177e4 LT |
44 | |
45 | #include <asm/processor.h> | |
46 | #include <asm/msr.h> | |
1da177e4 LT |
47 | #include <asm/system.h> |
48 | ||
8874b414 | 49 | static struct class *cpuid_class; |
1da177e4 | 50 | |
2347d933 PA |
51 | struct cpuid_regs { |
52 | u32 eax, ebx, ecx, edx; | |
1da177e4 LT |
53 | }; |
54 | ||
55 | static void cpuid_smp_cpuid(void *cmd_block) | |
56 | { | |
2347d933 | 57 | struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block; |
1da177e4 | 58 | |
2347d933 PA |
59 | cpuid_count(cmd->eax, cmd->ecx, |
60 | &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx); | |
1da177e4 LT |
61 | } |
62 | ||
1da177e4 LT |
63 | static loff_t cpuid_seek(struct file *file, loff_t offset, int orig) |
64 | { | |
65 | loff_t ret; | |
2b06ac86 | 66 | struct inode *inode = file->f_mapping->host; |
1da177e4 | 67 | |
2b06ac86 | 68 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
69 | switch (orig) { |
70 | case 0: | |
71 | file->f_pos = offset; | |
72 | ret = file->f_pos; | |
73 | break; | |
74 | case 1: | |
75 | file->f_pos += offset; | |
76 | ret = file->f_pos; | |
77 | break; | |
78 | default: | |
79 | ret = -EINVAL; | |
80 | } | |
2b06ac86 | 81 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
82 | return ret; |
83 | } | |
84 | ||
85 | static ssize_t cpuid_read(struct file *file, char __user *buf, | |
f634fa94 | 86 | size_t count, loff_t *ppos) |
1da177e4 LT |
87 | { |
88 | char __user *tmp = buf; | |
2347d933 | 89 | struct cpuid_regs cmd; |
aab4c5a5 | 90 | int cpu = iminor(file->f_path.dentry->d_inode); |
2347d933 | 91 | u64 pos = *ppos; |
9ea2b82e PA |
92 | ssize_t bytes = 0; |
93 | int err = 0; | |
1da177e4 LT |
94 | |
95 | if (count % 16) | |
96 | return -EINVAL; /* Invalid chunk size */ | |
97 | ||
6b7f430e | 98 | for (; count; count -= 16) { |
2347d933 PA |
99 | cmd.eax = pos; |
100 | cmd.ecx = pos >> 32; | |
4b46ca70 PA |
101 | err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1); |
102 | if (err) | |
9ea2b82e PA |
103 | break; |
104 | if (copy_to_user(tmp, &cmd, 16)) { | |
105 | err = -EFAULT; | |
106 | break; | |
107 | } | |
1da177e4 | 108 | tmp += 16; |
9ea2b82e | 109 | bytes += 16; |
2347d933 | 110 | *ppos = ++pos; |
1da177e4 LT |
111 | } |
112 | ||
9ea2b82e | 113 | return bytes ? bytes : err; |
1da177e4 LT |
114 | } |
115 | ||
116 | static int cpuid_open(struct inode *inode, struct file *file) | |
117 | { | |
5119e92e JC |
118 | unsigned int cpu; |
119 | struct cpuinfo_x86 *c; | |
5119e92e JC |
120 | |
121 | cpu = iminor(file->f_path.dentry->d_inode); | |
5a943617 JK |
122 | if (cpu >= nr_cpu_ids || !cpu_online(cpu)) |
123 | return -ENXIO; /* No such CPU */ | |
124 | ||
5119e92e | 125 | c = &cpu_data(cpu); |
1da177e4 | 126 | if (c->cpuid_level < 0) |
5a943617 JK |
127 | return -EIO; /* CPUID not supported */ |
128 | ||
129 | return 0; | |
1da177e4 LT |
130 | } |
131 | ||
132 | /* | |
133 | * File operations we support | |
134 | */ | |
5dfe4c96 | 135 | static const struct file_operations cpuid_fops = { |
1da177e4 LT |
136 | .owner = THIS_MODULE, |
137 | .llseek = cpuid_seek, | |
138 | .read = cpuid_read, | |
139 | .open = cpuid_open, | |
140 | }; | |
141 | ||
1f503e77 | 142 | static __cpuinit int cpuid_device_create(int cpu) |
1da177e4 | 143 | { |
07accdc1 | 144 | struct device *dev; |
1da177e4 | 145 | |
a9b12619 GKH |
146 | dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL, |
147 | "cpu%d", cpu); | |
1f503e77 AM |
148 | return IS_ERR(dev) ? PTR_ERR(dev) : 0; |
149 | } | |
150 | ||
151 | static void cpuid_device_destroy(int cpu) | |
152 | { | |
153 | device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu)); | |
1da177e4 LT |
154 | } |
155 | ||
1e32b073 SS |
156 | static int __cpuinit cpuid_class_cpu_callback(struct notifier_block *nfb, |
157 | unsigned long action, | |
158 | void *hcpu) | |
1da177e4 LT |
159 | { |
160 | unsigned int cpu = (unsigned long)hcpu; | |
1f503e77 | 161 | int err = 0; |
1da177e4 LT |
162 | |
163 | switch (action) { | |
1f503e77 | 164 | case CPU_UP_PREPARE: |
1f503e77 | 165 | err = cpuid_device_create(cpu); |
1da177e4 | 166 | break; |
1f503e77 | 167 | case CPU_UP_CANCELED: |
b844eba2 | 168 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 169 | case CPU_DEAD: |
1f503e77 | 170 | cpuid_device_destroy(cpu); |
1da177e4 LT |
171 | break; |
172 | } | |
1f503e77 | 173 | return err ? NOTIFY_BAD : NOTIFY_OK; |
1da177e4 LT |
174 | } |
175 | ||
c72258c7 | 176 | static struct notifier_block __refdata cpuid_class_cpu_notifier = |
1da177e4 LT |
177 | { |
178 | .notifier_call = cpuid_class_cpu_callback, | |
179 | }; | |
180 | ||
e454cea2 | 181 | static char *cpuid_devnode(struct device *dev, mode_t *mode) |
07e9bb8e KS |
182 | { |
183 | return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt)); | |
184 | } | |
185 | ||
1da177e4 LT |
186 | static int __init cpuid_init(void) |
187 | { | |
188 | int i, err = 0; | |
189 | i = 0; | |
190 | ||
0b962d47 PA |
191 | if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS, |
192 | "cpu/cpuid", &cpuid_fops)) { | |
1da177e4 LT |
193 | printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n", |
194 | CPUID_MAJOR); | |
195 | err = -EBUSY; | |
196 | goto out; | |
197 | } | |
8874b414 | 198 | cpuid_class = class_create(THIS_MODULE, "cpuid"); |
1da177e4 LT |
199 | if (IS_ERR(cpuid_class)) { |
200 | err = PTR_ERR(cpuid_class); | |
201 | goto out_chrdev; | |
202 | } | |
e454cea2 | 203 | cpuid_class->devnode = cpuid_devnode; |
1da177e4 | 204 | for_each_online_cpu(i) { |
07accdc1 | 205 | err = cpuid_device_create(i); |
2347d933 | 206 | if (err != 0) |
1da177e4 LT |
207 | goto out_class; |
208 | } | |
b6a7c79a | 209 | register_hotcpu_notifier(&cpuid_class_cpu_notifier); |
1da177e4 LT |
210 | |
211 | err = 0; | |
212 | goto out; | |
213 | ||
214 | out_class: | |
215 | i = 0; | |
216 | for_each_online_cpu(i) { | |
1f503e77 | 217 | cpuid_device_destroy(i); |
1da177e4 | 218 | } |
8874b414 | 219 | class_destroy(cpuid_class); |
1da177e4 | 220 | out_chrdev: |
0b962d47 | 221 | __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid"); |
1da177e4 LT |
222 | out: |
223 | return err; | |
224 | } | |
225 | ||
226 | static void __exit cpuid_exit(void) | |
227 | { | |
228 | int cpu = 0; | |
229 | ||
230 | for_each_online_cpu(cpu) | |
1f503e77 | 231 | cpuid_device_destroy(cpu); |
8874b414 | 232 | class_destroy(cpuid_class); |
da482474 | 233 | __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid"); |
b6a7c79a | 234 | unregister_hotcpu_notifier(&cpuid_class_cpu_notifier); |
1da177e4 LT |
235 | } |
236 | ||
237 | module_init(cpuid_init); | |
238 | module_exit(cpuid_exit); | |
239 | ||
240 | MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>"); | |
241 | MODULE_DESCRIPTION("x86 generic CPUID driver"); | |
242 | MODULE_LICENSE("GPL"); |