Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* ----------------------------------------------------------------------- * |
2b06ac86 PA |
2 | * |
3 | * Copyright 2000-2008 H. Peter Anvin - All Rights Reserved | |
ff55df53 | 4 | * Copyright 2009 Intel Corporation; author: H. Peter Anvin |
1da177e4 LT |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139, | |
9 | * USA; either version 2 of the License, or (at your option) any later | |
10 | * version; incorporated herein by reference. | |
11 | * | |
12 | * ----------------------------------------------------------------------- */ | |
13 | ||
14 | /* | |
1da177e4 LT |
15 | * x86 MSR access device |
16 | * | |
17 | * This device is accessed by lseek() to the appropriate register number | |
18 | * and then read/write in chunks of 8 bytes. A larger size means multiple | |
19 | * reads or writes of the same register. | |
20 | * | |
21 | * This driver uses /dev/cpu/%d/msr where %d is the minor number, and on | |
22 | * an SMP box will direct the access to CPU %d. | |
23 | */ | |
24 | ||
25 | #include <linux/module.h> | |
1da177e4 LT |
26 | |
27 | #include <linux/types.h> | |
28 | #include <linux/errno.h> | |
29 | #include <linux/fcntl.h> | |
30 | #include <linux/init.h> | |
31 | #include <linux/poll.h> | |
32 | #include <linux/smp.h> | |
1da177e4 LT |
33 | #include <linux/major.h> |
34 | #include <linux/fs.h> | |
35 | #include <linux/device.h> | |
36 | #include <linux/cpu.h> | |
37 | #include <linux/notifier.h> | |
448dd2fa | 38 | #include <linux/uaccess.h> |
5a0e3ad6 | 39 | #include <linux/gfp.h> |
1da177e4 LT |
40 | |
41 | #include <asm/processor.h> | |
42 | #include <asm/msr.h> | |
1da177e4 | 43 | |
8874b414 | 44 | static struct class *msr_class; |
1da177e4 | 45 | |
1da177e4 LT |
46 | static loff_t msr_seek(struct file *file, loff_t offset, int orig) |
47 | { | |
2b06ac86 PA |
48 | loff_t ret; |
49 | struct inode *inode = file->f_mapping->host; | |
1da177e4 | 50 | |
2b06ac86 | 51 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
52 | switch (orig) { |
53 | case 0: | |
54 | file->f_pos = offset; | |
55 | ret = file->f_pos; | |
56 | break; | |
57 | case 1: | |
58 | file->f_pos += offset; | |
59 | ret = file->f_pos; | |
2b06ac86 PA |
60 | break; |
61 | default: | |
62 | ret = -EINVAL; | |
1da177e4 | 63 | } |
2b06ac86 | 64 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
65 | return ret; |
66 | } | |
67 | ||
94a9fa41 PC |
68 | static ssize_t msr_read(struct file *file, char __user *buf, |
69 | size_t count, loff_t *ppos) | |
1da177e4 LT |
70 | { |
71 | u32 __user *tmp = (u32 __user *) buf; | |
72 | u32 data[2]; | |
1da177e4 | 73 | u32 reg = *ppos; |
aab4c5a5 | 74 | int cpu = iminor(file->f_path.dentry->d_inode); |
85f1cb60 PA |
75 | int err = 0; |
76 | ssize_t bytes = 0; | |
1da177e4 LT |
77 | |
78 | if (count % 8) | |
79 | return -EINVAL; /* Invalid chunk size */ | |
80 | ||
6926d570 | 81 | for (; count; count -= 8) { |
78a62d2c | 82 | err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]); |
0cc0213e | 83 | if (err) |
85f1cb60 | 84 | break; |
85f1cb60 PA |
85 | if (copy_to_user(tmp, &data, 8)) { |
86 | err = -EFAULT; | |
87 | break; | |
c6f31932 | 88 | } |
1da177e4 | 89 | tmp += 2; |
85f1cb60 | 90 | bytes += 8; |
1da177e4 LT |
91 | } |
92 | ||
85f1cb60 | 93 | return bytes ? bytes : err; |
1da177e4 LT |
94 | } |
95 | ||
96 | static ssize_t msr_write(struct file *file, const char __user *buf, | |
97 | size_t count, loff_t *ppos) | |
98 | { | |
99 | const u32 __user *tmp = (const u32 __user *)buf; | |
100 | u32 data[2]; | |
1da177e4 | 101 | u32 reg = *ppos; |
aab4c5a5 | 102 | int cpu = iminor(file->f_path.dentry->d_inode); |
85f1cb60 PA |
103 | int err = 0; |
104 | ssize_t bytes = 0; | |
1da177e4 LT |
105 | |
106 | if (count % 8) | |
107 | return -EINVAL; /* Invalid chunk size */ | |
108 | ||
f475ff35 | 109 | for (; count; count -= 8) { |
85f1cb60 PA |
110 | if (copy_from_user(&data, tmp, 8)) { |
111 | err = -EFAULT; | |
112 | break; | |
113 | } | |
78a62d2c | 114 | err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]); |
0cc0213e | 115 | if (err) |
85f1cb60 | 116 | break; |
1da177e4 | 117 | tmp += 2; |
85f1cb60 | 118 | bytes += 8; |
1da177e4 LT |
119 | } |
120 | ||
85f1cb60 | 121 | return bytes ? bytes : err; |
1da177e4 LT |
122 | } |
123 | ||
ff55df53 PA |
124 | static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg) |
125 | { | |
126 | u32 __user *uregs = (u32 __user *)arg; | |
127 | u32 regs[8]; | |
128 | int cpu = iminor(file->f_path.dentry->d_inode); | |
129 | int err; | |
130 | ||
131 | switch (ioc) { | |
132 | case X86_IOC_RDMSR_REGS: | |
133 | if (!(file->f_mode & FMODE_READ)) { | |
134 | err = -EBADF; | |
135 | break; | |
136 | } | |
137 | if (copy_from_user(®s, uregs, sizeof regs)) { | |
138 | err = -EFAULT; | |
139 | break; | |
140 | } | |
141 | err = rdmsr_safe_regs_on_cpu(cpu, regs); | |
142 | if (err) | |
143 | break; | |
144 | if (copy_to_user(uregs, ®s, sizeof regs)) | |
145 | err = -EFAULT; | |
146 | break; | |
147 | ||
148 | case X86_IOC_WRMSR_REGS: | |
149 | if (!(file->f_mode & FMODE_WRITE)) { | |
150 | err = -EBADF; | |
151 | break; | |
152 | } | |
153 | if (copy_from_user(®s, uregs, sizeof regs)) { | |
154 | err = -EFAULT; | |
155 | break; | |
156 | } | |
157 | err = wrmsr_safe_regs_on_cpu(cpu, regs); | |
158 | if (err) | |
159 | break; | |
160 | if (copy_to_user(uregs, ®s, sizeof regs)) | |
161 | err = -EFAULT; | |
162 | break; | |
163 | ||
164 | default: | |
165 | err = -ENOTTY; | |
166 | break; | |
167 | } | |
168 | ||
169 | return err; | |
170 | } | |
171 | ||
1da177e4 LT |
172 | static int msr_open(struct inode *inode, struct file *file) |
173 | { | |
494c2ebf PA |
174 | unsigned int cpu; |
175 | struct cpuinfo_x86 *c; | |
1da177e4 | 176 | |
5119e92e | 177 | cpu = iminor(file->f_path.dentry->d_inode); |
d6c30405 FW |
178 | if (cpu >= nr_cpu_ids || !cpu_online(cpu)) |
179 | return -ENXIO; /* No such CPU */ | |
180 | ||
5119e92e JC |
181 | c = &cpu_data(cpu); |
182 | if (!cpu_has(c, X86_FEATURE_MSR)) | |
d6c30405 FW |
183 | return -EIO; /* MSR not supported */ |
184 | ||
185 | return 0; | |
1da177e4 LT |
186 | } |
187 | ||
188 | /* | |
189 | * File operations we support | |
190 | */ | |
5dfe4c96 | 191 | static const struct file_operations msr_fops = { |
1da177e4 LT |
192 | .owner = THIS_MODULE, |
193 | .llseek = msr_seek, | |
194 | .read = msr_read, | |
195 | .write = msr_write, | |
196 | .open = msr_open, | |
ff55df53 PA |
197 | .unlocked_ioctl = msr_ioctl, |
198 | .compat_ioctl = msr_ioctl, | |
1da177e4 LT |
199 | }; |
200 | ||
38048983 | 201 | static int __cpuinit msr_device_create(int cpu) |
1da177e4 | 202 | { |
a271aaf1 | 203 | struct device *dev; |
1da177e4 | 204 | |
a9b12619 GKH |
205 | dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu), NULL, |
206 | "msr%d", cpu); | |
881a841f AM |
207 | return IS_ERR(dev) ? PTR_ERR(dev) : 0; |
208 | } | |
209 | ||
210 | static void msr_device_destroy(int cpu) | |
211 | { | |
212 | device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu)); | |
1da177e4 LT |
213 | } |
214 | ||
761c4bf8 | 215 | static int __cpuinit msr_class_cpu_callback(struct notifier_block *nfb, |
e09793bb | 216 | unsigned long action, void *hcpu) |
1da177e4 LT |
217 | { |
218 | unsigned int cpu = (unsigned long)hcpu; | |
881a841f | 219 | int err = 0; |
1da177e4 LT |
220 | |
221 | switch (action) { | |
881a841f | 222 | case CPU_UP_PREPARE: |
881a841f | 223 | err = msr_device_create(cpu); |
1da177e4 | 224 | break; |
881a841f | 225 | case CPU_UP_CANCELED: |
b844eba2 | 226 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 227 | case CPU_DEAD: |
881a841f | 228 | msr_device_destroy(cpu); |
1da177e4 LT |
229 | break; |
230 | } | |
a94247e7 | 231 | return notifier_from_errno(err); |
1da177e4 LT |
232 | } |
233 | ||
c72258c7 | 234 | static struct notifier_block __refdata msr_class_cpu_notifier = { |
1da177e4 LT |
235 | .notifier_call = msr_class_cpu_callback, |
236 | }; | |
237 | ||
2c9ede55 | 238 | static char *msr_devnode(struct device *dev, umode_t *mode) |
07e9bb8e KS |
239 | { |
240 | return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt)); | |
241 | } | |
242 | ||
1da177e4 LT |
243 | static int __init msr_init(void) |
244 | { | |
245 | int i, err = 0; | |
246 | i = 0; | |
247 | ||
0b962d47 | 248 | if (__register_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr", &msr_fops)) { |
1da177e4 LT |
249 | printk(KERN_ERR "msr: unable to get major %d for msr\n", |
250 | MSR_MAJOR); | |
251 | err = -EBUSY; | |
252 | goto out; | |
253 | } | |
8874b414 | 254 | msr_class = class_create(THIS_MODULE, "msr"); |
1da177e4 LT |
255 | if (IS_ERR(msr_class)) { |
256 | err = PTR_ERR(msr_class); | |
257 | goto out_chrdev; | |
258 | } | |
e454cea2 | 259 | msr_class->devnode = msr_devnode; |
a2db672a | 260 | get_online_cpus(); |
1da177e4 | 261 | for_each_online_cpu(i) { |
a271aaf1 | 262 | err = msr_device_create(i); |
1da177e4 LT |
263 | if (err != 0) |
264 | goto out_class; | |
265 | } | |
e09793bb | 266 | register_hotcpu_notifier(&msr_class_cpu_notifier); |
a2db672a | 267 | put_online_cpus(); |
1da177e4 LT |
268 | |
269 | err = 0; | |
270 | goto out; | |
271 | ||
272 | out_class: | |
273 | i = 0; | |
274 | for_each_online_cpu(i) | |
881a841f | 275 | msr_device_destroy(i); |
a2db672a | 276 | put_online_cpus(); |
8874b414 | 277 | class_destroy(msr_class); |
1da177e4 | 278 | out_chrdev: |
0b962d47 | 279 | __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr"); |
1da177e4 LT |
280 | out: |
281 | return err; | |
282 | } | |
283 | ||
284 | static void __exit msr_exit(void) | |
285 | { | |
286 | int cpu = 0; | |
a2db672a | 287 | get_online_cpus(); |
1da177e4 | 288 | for_each_online_cpu(cpu) |
881a841f | 289 | msr_device_destroy(cpu); |
8874b414 | 290 | class_destroy(msr_class); |
da482474 | 291 | __unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr"); |
e09793bb | 292 | unregister_hotcpu_notifier(&msr_class_cpu_notifier); |
a2db672a | 293 | put_online_cpus(); |
1da177e4 LT |
294 | } |
295 | ||
296 | module_init(msr_init); | |
297 | module_exit(msr_exit) | |
298 | ||
299 | MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>"); | |
300 | MODULE_DESCRIPTION("x86 generic MSR driver"); | |
301 | MODULE_LICENSE("GPL"); |