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authorThomas Gleixner <tglx@linutronix.de>2007-10-11 05:17:01 -0400
committerThomas Gleixner <tglx@linutronix.de>2007-10-11 05:17:01 -0400
commit9a163ed8e0552fdcffe405d2ea7134819a81456e (patch)
treeb322fd2afbb812ba7ddfd22f3734aaab007c2aa5 /arch/x86/kernel/cpuid.c
parentf7627e2513987bb5d4e8cb13c4e0a478352141ac (diff)
i386: move kernel
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/cpuid.c')
-rw-r--r--arch/x86/kernel/cpuid.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
new file mode 100644
index 000000000000..5c2faa10e9fa
--- /dev/null
+++ b/arch/x86/kernel/cpuid.c
@@ -0,0 +1,242 @@
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
28#include <linux/types.h>
29#include <linux/errno.h>
30#include <linux/fcntl.h>
31#include <linux/init.h>
32#include <linux/poll.h>
33#include <linux/smp.h>
34#include <linux/major.h>
35#include <linux/fs.h>
36#include <linux/smp_lock.h>
37#include <linux/device.h>
38#include <linux/cpu.h>
39#include <linux/notifier.h>
40
41#include <asm/processor.h>
42#include <asm/msr.h>
43#include <asm/uaccess.h>
44#include <asm/system.h>
45
46static struct class *cpuid_class;
47
48#ifdef CONFIG_SMP
49
50struct cpuid_command {
51 u32 reg;
52 u32 *data;
53};
54
55static void cpuid_smp_cpuid(void *cmd_block)
56{
57 struct cpuid_command *cmd = (struct cpuid_command *)cmd_block;
58
59 cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2],
60 &cmd->data[3]);
61}
62
63static inline void do_cpuid(int cpu, u32 reg, u32 * data)
64{
65 struct cpuid_command cmd;
66
67 preempt_disable();
68 if (cpu == smp_processor_id()) {
69 cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
70 } else {
71 cmd.reg = reg;
72 cmd.data = data;
73
74 smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
75 }
76 preempt_enable();
77}
78#else /* ! CONFIG_SMP */
79
80static inline void do_cpuid(int cpu, u32 reg, u32 * data)
81{
82 cpuid(reg, &data[0], &data[1], &data[2], &data[3]);
83}
84
85#endif /* ! CONFIG_SMP */
86
87static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
88{
89 loff_t ret;
90
91 lock_kernel();
92
93 switch (orig) {
94 case 0:
95 file->f_pos = offset;
96 ret = file->f_pos;
97 break;
98 case 1:
99 file->f_pos += offset;
100 ret = file->f_pos;
101 break;
102 default:
103 ret = -EINVAL;
104 }
105
106 unlock_kernel();
107 return ret;
108}
109
110static ssize_t cpuid_read(struct file *file, char __user *buf,
111 size_t count, loff_t * ppos)
112{
113 char __user *tmp = buf;
114 u32 data[4];
115 u32 reg = *ppos;
116 int cpu = iminor(file->f_path.dentry->d_inode);
117
118 if (count % 16)
119 return -EINVAL; /* Invalid chunk size */
120
121 for (; count; count -= 16) {
122 do_cpuid(cpu, reg, data);
123 if (copy_to_user(tmp, &data, 16))
124 return -EFAULT;
125 tmp += 16;
126 *ppos = reg++;
127 }
128
129 return tmp - buf;
130}
131
132static int cpuid_open(struct inode *inode, struct file *file)
133{
134 unsigned int cpu = iminor(file->f_path.dentry->d_inode);
135 struct cpuinfo_x86 *c = &(cpu_data)[cpu];
136
137 if (cpu >= NR_CPUS || !cpu_online(cpu))
138 return -ENXIO; /* No such CPU */
139 if (c->cpuid_level < 0)
140 return -EIO; /* CPUID not supported */
141
142 return 0;
143}
144
145/*
146 * File operations we support
147 */
148static const struct file_operations cpuid_fops = {
149 .owner = THIS_MODULE,
150 .llseek = cpuid_seek,
151 .read = cpuid_read,
152 .open = cpuid_open,
153};
154
155static int cpuid_device_create(int i)
156{
157 int err = 0;
158 struct device *dev;
159
160 dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, i), "cpu%d",i);
161 if (IS_ERR(dev))
162 err = PTR_ERR(dev);
163 return err;
164}
165
166static int cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
167{
168 unsigned int cpu = (unsigned long)hcpu;
169
170 switch (action) {
171 case CPU_ONLINE:
172 case CPU_ONLINE_FROZEN:
173 cpuid_device_create(cpu);
174 break;
175 case CPU_DEAD:
176 case CPU_DEAD_FROZEN:
177 device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
178 break;
179 }
180 return NOTIFY_OK;
181}
182
183static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier =
184{
185 .notifier_call = cpuid_class_cpu_callback,
186};
187
188static int __init cpuid_init(void)
189{
190 int i, err = 0;
191 i = 0;
192
193 if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
194 printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
195 CPUID_MAJOR);
196 err = -EBUSY;
197 goto out;
198 }
199 cpuid_class = class_create(THIS_MODULE, "cpuid");
200 if (IS_ERR(cpuid_class)) {
201 err = PTR_ERR(cpuid_class);
202 goto out_chrdev;
203 }
204 for_each_online_cpu(i) {
205 err = cpuid_device_create(i);
206 if (err != 0)
207 goto out_class;
208 }
209 register_hotcpu_notifier(&cpuid_class_cpu_notifier);
210
211 err = 0;
212 goto out;
213
214out_class:
215 i = 0;
216 for_each_online_cpu(i) {
217 device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i));
218 }
219 class_destroy(cpuid_class);
220out_chrdev:
221 unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
222out:
223 return err;
224}
225
226static void __exit cpuid_exit(void)
227{
228 int cpu = 0;
229
230 for_each_online_cpu(cpu)
231 device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
232 class_destroy(cpuid_class);
233 unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
234 unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
235}
236
237module_init(cpuid_init);
238module_exit(cpuid_exit);
239
240MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
241MODULE_DESCRIPTION("x86 generic CPUID driver");
242MODULE_LICENSE("GPL");